Guidance for
Federal Land Management
in the Chesapeake Bay Watershed
-------
Jane Thomas/Integration and
Application Network (IAN),
University of Maryland Center for
Environmental Science
Mary Hollinger/NOAA
Photo Library
Ben Longstaff/lntegration and
Application Network (IAN),
University of Maryland Center for
Environmental Science
istockphoto.com
istockphoto.com
Jane Hawkey/Integration and
Application Network (IAN),
University of Maryland Center for
Environmental Science
Jane Thomas/Integration and
Application Network (IAN),
University of Maryland Center for
Environmental Science
Emily Nauman/lntegration and Application Network (IAN),
University of Maryland Center for Environmental Science
-------
Guidance for
Federal Land Management
in the Chesapeake Bay Watershed
EPA 841-R-10-002
May 12, 2010
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
Chapter 1.
Introduction
1 Background
On May 12, 2009, President Barack Obama signed Executive Order 13508, which recognizes
the Chesapeake Bay as a national treasure and calls on the federal government to lead a
renewed effort to restore and protect the nation's largest estuary and its watershed. In the
Executive Order, the President states that despite significant efforts by federal, state, and local
governments and other interested parties, water pollution in the Chesapeake Bay prevents the
attainment of existing state water quality standards and the fishable and swimmable goals of the
Clean Water Act. The President further notes that at the current level and scope of pollution
control within the Chesapeake Bay's watershed, restoration of the Chesapeake Bay is not
expected for many years. Nutrients (forms of both nitrogen and phosphorus) and sediment
delivered from the Chesapeake Bay watershed are the pollutants largely responsible for the
continued degradation and restoration complexities of the Chesapeake Bay.
The Executive Order expresses the great challenge facing our renewed efforts to restore the
health of the Chesapeake Bay,
Restoration of the health of the Chesapeake Bay will require a renewed
commitment to controlling pollution from all sources as well as protecting and
restoring habitat and living resources, conserving lands, and improving
management of natural resources, all of which contribute to improved water
quality and ecosystem health.
To meet that challenge, the Executive Order lays out a series of steps. One of the first key steps
requires the federal agencies to define the "next generation of tools and actions to restore water
quality in the Chesapeake Bay and describe the changes to be made to regulations, programs,
and policies to implement these actions." The Executive Order assigns the lead responsibility to
the U.S. Environmental Protection Agency (EPA), and the federal government published the
final report on November 24, 2009. The report is at http://executiveorder.chesapeakebay.net
(President Barack Obama 2009).
Chapter 1. Introduction 1-1
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
Another key step in the Executive Order is for EPA to publish this guidance document. Section
502 of the Executive Order states,
The Administrator of the EPA shall, within 1 year of the date of this order and
after consulting with the Committee and providing for public review and
comment, publish guidance for Federal land management in the Chesapeake
Bay watershed describing proven, cost-effective tools and practices that reduce
water pollution, including practices that are available for use by Federal
agencies.
2 Purpose of This Document
This document provides information and data on land management practices for federal
agencies with land, facilities, or installation management responsibilities affecting 10 or more
acres within the watershed of the Chesapeake Bay to contribute toward the restoration of the
Chesapeake Bay and its watershed. The ultimate goal of the Executive Order—to restore the
health of the Chesapeake Bay—is very high. Yet, as the Executive Order states, the
Chesapeake Bay is, "one of the largest and most biologically productive estuaries in the world."
It is certainly deserving of the ambitious effort laid out in the Executive Order.
However, we cannot underestimate the challenge. In particular, abating nonpoint source1
pollution, which is the focus of this document, presents a huge challenge to the recovery of the
Bay. Unless we adequately address the vast majority of nonpoint source pollution, the
Chesapeake Bay will not be restored. Consider the following:
• Almost half of all the nitrogen and phosphorus pollution delivered to the Chesapeake
Bay derive from agricultural sources, from both livestock production and row crop land.
• In addition to contributing 31 percent of phosphorus loads and 11 percent of nitrogen
loads to the Bay, urban runoff and stormwater sources compose the only significant
pollutant source category that is increasing in the Bay watershed.
• River basins with the highest percentage of agricultural lands yield the highest overall
amount of sediment each year, while basins with the highest percentage of forest cover
yield the lowest amount of sediment.
1 This document uses the term nonpoint source broadly, as EPA has in the past, to refer to sources that are treated
as nonpoint sources in EPA's implementation of section 319 of the Clean Water Act. Some of those sources may
legally be made subject to regulation as point sources under section 402(p) of the Clean Water Act. EPA has
designated several categories of those stormwater sources for regulation, such as small municipal separate storm
sewer systems, and may designate others for regulation in the future.
1-2 Chapter 1. Introduction
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
• On a per-acre basis, construction sites can contribute the most sediment of all land
uses—as much as 10 to 20 times that of agricultural lands.
• A large percentage of riparian buffers in the Chesapeake Bay have been lost or
degraded. While the Chesapeake Bay Commission set a goal in 2004 to achieve buffer
along 70 percent of riparian lands, the percentage currently stands at 60 percent.
For those and other reasons, it is critically important that we achieve, at a minimum, the
nonpoint source implementation measures set forth in this document for the various land
management categories. The implementation measures are designed to promote the use of the
best, cost-effective and reasonable practices available to achieve the Executive Order's broad
and ambitious goals for the Chesapeake Bay. In turn, the practices and actions described and
recommended in this document are those that are indicated by the current, state-of-the-art
scientific and technical literature to be the most effective and cost-effective in achieving the
Chesapeake Bay goals. Thus, the information presented in this document will enable
practitioners to design and implement on-the-ground solutions that collectively will move the
entire watershed toward achieving the goals.
Note: This document provides guidance regarding practices that may be used to reduce
nonpoint source pollution in the Chesapeake Bay and other waterbodies. At times, this
document refers to statutory and regulatory provisions that contain legally binding requirements.
This document does not substitute for those provisions or regulations, nor is it a regulation itself.
Thus, it does not impose legally binding requirements on EPA, other federal agencies, or any
other entity and might not apply to a particular situation according to the circumstances. EPA,
other Federal agencies and any other user of this document retain the discretion to adopt
approaches to control nonpoint source pollution that differ from this guidance where appropriate.
EPA may change this guidance in the future.
3 Scope
As required by Section 502 of the Executive Order, this document (1) provides guidance for
federal land management in the Chesapeake Bay and (2) describes proven, cost-effective tools
and practices that reduce water pollution, including practices that are available for use by
federal agencies. Federal agencies in the Chesapeake Bay watershed will find this guidance
useful in managing their lands, ranging from the development and redevelopment of federal
facilities to managing agricultural, forested, riparian, and other land areas the federal
government owns or manages.
Chapter 1. Introduction 1-3
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
At the same time, the great majority of land in the Chesapeake Bay watershed is nonfederal
land that private landowners, states, and local governments manage. Indeed, the vast majority
of actions to restore the Chesapeake Bay will need to take place on nonfederal lands, and
nonfederal actors will be implementing them. From the perspective of land management and
water quality restoration/protection, the same set of "proven cost-effective tools and practices
that reduce water pollution" are appropriate for both federal and nonfederal land managers to
restore and protect the Chesapeake Bay.
Therefore, states and others (e.g., states, local governments, conservation districts, watershed
groups, developers, farmers and other citizens in the Chesapeake Bay watershed) may choose
to use this guidance document to the extent that they find it relevant and useful to their needs.
The document presents practices and actions that are not unique to federal lands and thus will
often be applicable to lands that are managed by nonfederal land managers. Thus, while this
document has been written specifically to address the needs of federal land managers, other
parties may also find it to provide a useful guide to implementing the most effective and cost-
effective practices available to restore and protect the Chesapeake Bay.
In addition, many of the nutrient and sediment sources in the Chesapeake Bay watershed are
similar to sources in other watersheds around the country. Many of the practices needed to
protect and restore the Bay are the same as or very similar to those used in other large-scale,
multistate watersheds in the country. Indeed, while great efforts have been made in preparing
this document to assure the consideration of all relevant data on the Chesapeake Bay
watershed, data from outside the Bay watershed have also been used when deemed relevant
and applicable to the Bay. For that reason, much of the information provided in this document is
relevant to other areas of the United States. Therefore, practitioners outside the watershed may
wish consider this guidance document as they develop and implement their own watershed
plans and strategies to address nutrient and sediment pollution from nonpoint sources.
This document provides information pertaining to all the major categories and subcategories of
nonpoint source pollution that are relevant to the Chesapeake Bay. Those categories include
agriculture, urban and suburban development, hydromodification, decentralized wastewater
treatment, forestry, and riparian streamside areas.
Each chapter describes the problem presented by the relevant nonpoint source category or
subcategory of activity and its relevance to the Chesapeake Bay's recovery. Each chapter
states the key goals that readers should strive to achieve to attain the ambitious overall goals
for the Chesapeake Bay set forth in the Executive Order. The goals are accompanied by
information and data on the cost-effective tools and practices that practitioners can employ to
help achieve the goals. It also provides available effectiveness data and cost data.
1-4 Chapter 1. Introduction
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
4 Relationship to Previous Documents
EPA has produced a considerable amount of technical information regarding the effectiveness
and costs of various measures and practices to address nonpoint source pollution in the past. In
1993, as required by section 6217 of the Coastal Zone Act Amendments of 1990, EPA
published the Guidance Specifying Management Measures for Sources of Nonpoint Pollution in
Coastal Waters (USEPA 1993), which contains chapters on agriculture, forestry, urban runoff,
marinas and recreational boating, hydromodification, and wetlands and riparian areas (see
http://www.epa.gov/owow/nps/MMGI/). Section 6217 defines management measures as,
"economically achievable measures for the control of the addition of pollutants...which reflect the
greatest degree of pollutant reduction achievable through the application of the best available
nonpoint pollution control practices, technologies, processes, siting criteria, operating methods,
or other alternatives." The 1993 guidance includes a set of management measures in each
chapter and then provides information on available practices, their effectiveness, and their
costs.
The National Management Measures volumes expand a chapter from the 1993 coastal
guidance into an entire book series that contains national management measures patterned
after the coastal guidance, complete with updated data (see
http://www.epa.gov/owow/nps/pubs.html). All the practices and actions in the National
Management Measures books are based on those established in the 1993 publication, but the
newer publications provide updated information and addresses to some extent select newly
emerging issues and practices. The six National Management Measures books are
• National Management Measures for the Control of Nonpoint Pollution from Agriculture
(USEPA 2003)
• National Management Measures to Control Nonpoint Sources of Pollution from Forestry
(USEPA 2005b)
• National Management Measures to Protect and Restore Wetlands and Riparian Areas
for the Abatement of Nonpoint Source Pollution (USEPA 2005c)
• National Management Measures to Control Nonpoint Source Pollution from Urban Areas
(USEPA 2005d)
• Handbook for Managing Onsite and Clustered (Decentralized) Wastewater Treatment
Systems (USEPA 2005a)
• National Management Measures to Control Nonpoint Source Pollution from
Hydromodification (USEPA 2007)
Chapter 1. Introduction 1-5
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
This guidance document builds on those two earlier efforts but also differs in significant ways. It
focuses to a considerable extent on newer, more effective approaches to controlling some of the
most significant aspects of nonpoint pollution in the Chesapeake Bay watershed. Most
importantly, it responds to the imperative of implementing in the Chesapeake Bay watershed
those "next generation tools and actions" that reflect, in the words of the Executive Order, "a
renewed commitment to controlling pollution from all sources as well as protecting and restoring
habitat and living resources, conserving lands, and improving management of natural
resources, all of which contribute to improved water quality and ecosystem health."
5 Some Topics Receive New or Special Emphasis
The key areas in which this document focuses on next-generation tools and actions that go
beyond the previous nonpoint source guidance documents are the following:
1. Nutrient Management. This document focuses specifically on significantly expanding on
practices and actions that control the delivery of nutrients and sediment from agriculture by
employing a whole-farm nutrient management planning approach from source control and
avoidance, in-field control, and edge-of-field trapping and treatment. The practices and actions
presented here build from the most recent, state-of-the-art literature in nutrient management
planning and provide information on achieving reduced nutrient losses from both livestock
production on animal feeding operations and row crop agricultural lands.
2. Control of Urban Runoff and Stormwater. In this document, EPA recognizes and
emphasizes that hydrology is the principal driver of water quality impairments in developed and
developing areas. From that understanding, EPA establishes in this document a primary focus
on the goal of maintaining and restoring predevelopment hydrology to the maximum extent
technically feasible (METF). The guidance presents background information, data, examples,
and resources that demonstrate how practitioners can achieve that goal by implementing low
impact development (LID) and other green infrastructure techniques that infiltrate,
evapotranspire, and use rainwater on-site.
3. Turf Management. At 3.8 million acres, the total cultivated area for turf makes it the number
one crop grown in the Chesapeake Bay watershed. A significant portion of the turf is grown in a
manner that includes high inputs of fertilizers. Thus, turf management practices can at present
contribute a substantial amount of nutrient to the Chesapeake Bay. Therefore, this document
includes implementation measures that can help reduce nutrient runoff from turf.
4. Decentralized Wastewater Treatment Systems. This document presents an increased
emphasis on reducing nitrogen from decentralized systems, because of both the need to reduce
1-6 Chapter 1. Introduction
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
nutrient delivery to the Chesapeake Bay and the rapidly advancing state of the art. In addition,
this document uses the term decentralized systems rather than onsite systems, reflecting the
technical, feasibility, and management advantages of cluster treatment systems that treat
effluent from multiple lots at nearby off-site locations.
6 Some Topics are Addressed by Reference to
Existing Documents
Some nonpoint source practices remain important, but EPA has already adequately addressed
them in previous management measures documents and in other published literature. In those
cases, this document does not repetitively include details on those practices. (The six National
Management Measures books total approximately 1,500 pages.) Instead, this document briefly
acknowledges the issue or subject and then refers the reader to the appropriate existing
documents.
7 References
President Barack Obama. 2009. Executive Order 13508: Chesapeake Bay Protection and
Restoration. The White House, Office of the Press Secretary, Washington, DC.
. Accessed January 28, 2010.
USEPA (U.S. Environmental Protection Agency). 1993. Guidance Specifying Management
Measures for Sources of Nonpoint Pollution in Coastal Waters. EPA 840-B-92-002.
U.S. Environmental Protection Agency, Washington, DC.
USEPA (U.S. Environmental Protection Agency). 2003. National Management Measures to
Control Nonpoint Pollution from Agriculture. EPA 841-F-05-001. U.S. Environmental
Protection Agency, Washington, DC.
USEPA (U.S. Environmental Protection Agency). 2005a. Handbook for Managing Onsite and
Clustered (Decentralized) Wastewater Treatment Systems. EPA 832-B-05-001. Office of
Wastewater Management. Washington, DC.
USEPA (U.S. Environmental Protection Agency). 2005b. National Management Measures to
Control Nonpoint Sources of Pollution from Forestry. EPA 841-B-05-001.
U.S. Environmental Protection Agency, Office of Water, Washington, DC.
Chapter 1. Introduction 1-7
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
USEPA (U.S. Environmental Protection Agency). 2005c. National Management Measures to
Protect and Restore Wetlands and Riparian Areas for the Abatement ofNonpoint Source
Pollution. EPA 841-B-05-003. U.S. Environmental Protection Agency, Office of Water,
Washington, DC.
USEPA (U.S. Environmental Protection Agency). 2005d. National Management Measures to
Control Nonpoint Source Pollution from Urban Areas. EPA 841-B-05-004.
U.S. Environmental Protection Agency, Office of Water, Washington, DC.
USEPA (U.S. Environmental Protection Agency). 2007. National Management Measures to
Control Nonpoint Source Pollution from Hydromodification. EPA 841-B-07-002.
U.S. Environmental Protection Agency, Office of Water, Washington, DC.
1-8 Chapter 1. Introduction
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
Chapter 2.
Agriculture
Contents
1 Purpose and Overview 2-3
1.1 Need for an Agricultural Chapter 2-3
1.1.1 Purpose 2-3
1.1.2 Intended Audience 2-4
1.1.3 Water Quality Significance of Agricultural Runoff in the Chesapeake Bay
Watershed 2-4
1.1.4 Managing Agricultural Runoff to Reduce Nutrient and Sediment Loss 2-6
1.2 Overview of the Agriculture Chapter 2-7
1.2.1 Management Practices and Management Practice Systems 2-8
1.2.2 Implementation Measures for Agriculture in the Chesapeake Bay
Watershed to Control Nonpoint Source Nutrient and Sediment Pollution....2-12
2 Implementation Measures and Practices for Source Control and Avoidance 2-16
2.1 Cropland Agriculture 2-16
2.1.1 Nutrient Imbalance in the Chesapeake Bay Watershed 2-16
2.1.2 Nutrient Management 2-18
2.1.3 Alternative Crops 2-26
2.1.4 Land Retirement 2-27
2.1.5 Commercial Fertilizer Use 2-29
2.2 Animal Agriculture 2-31
2.2.1 Animal Feed Management 2-31
2.2.2 Manure Storage and Transport 2-35
2.2.3 Livestock Exclusion from Streams 2-38
2.2.4 Wastewater and Animal Wastes 2-41
3 Implementation Measures and Practices for Cropland In-Field Control 2-61
3.1 Field Nutrient Management 2-61
3.2 Sediment and Erosion Control 2-83
Chapter 2. Agriculture 2-1
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
3.3 Cover Crops 2-92
3.4 Pasture Land Management 2-102
3.5 Drainage System Design 2-109
4 Implementation Measures and Practices for Cropland Edge-of-Field Trapping and
Treatment 2-113
4.1 Buffers and Minimum Setbacks 2-113
4.2 Soil Amendment 2-122
4.3 Wetlands 2-123
4.4 Drainage Water Management 2-128
4.5 Animal Agriculture 2-140
5 References 2-147
Appendix 1: USDA National Conservation Practice Standards (Practice Codes) 2-181
Appendix 2: Agricultural Tools in Support of Section 502 Technical Guidance 2-223
I. Software and Models 2-226
II. Calculators, Spreadsheets, and Graphical Tools 2-233
III. Compilations of Tools 2-235
IV. Guidance and Other Technical Resources 2-236
2-2 Chapter 2. Agriculture
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
1 Purpose and Overview
1.1 Need for an Agricultural Chapter
1.1.1 Purpose
Approximately 87,000 farm operations and 8.5 million acres of cropland, or nearly a quarter of
the watershed, in the Chesapeake Bay watershed provide food and fiber, as well as significant
natural areas and aesthetic and environmental benefits. Farms in the Chesapeake Bay
watershed are very diverse. They vary greatly in size and produce a wide variety of products.
Today, according to the U.S. Department of Agriculture (USDA), more than 50 commodities are
produced in this region. The area's primary crops include corn, soybeans, wheat, hay, pasture,
vegetables, and fruits. The eastern part of the region is also home to a rapidly expanding
nursery and greenhouse industry.
On federal lands in the Chesapeake Bay watershed, approximately 30,396 acres are managed
for agricultural production. Specifically
• National Park Service: 14,669 acres
• USDA: 7,000 acres1
• Department of Defense: 5,588 acres
• Fish and Wildlife Service: 1,259 acres
The purpose of this document is to present an overview of the practices and information
resources available for federal land managers and others to achieve water quality goals in the
most cost-effective and potentially successful manner, with the overall objective of improving
water quality, habitat, and the environmental and economic resources of the Chesapeake Bay
and its tributaries.
This chapter provides a host of practices and actions that can be employed to reduce the
loadings of nitrogen (N), phosphorus (P), and sediment from agricultural activities to local
waters and the Chesapeake Bay. This chapter focuses on nutrient management on cropland
and the prevention of soil erosion from cropland, and on nutrient management in the production
1 USDA manages a number of large facilities in the Chesapeake Bay watershed. The Beltsville Agricultural Research
Center in Maryland is a leader in agricultural research and, at approximately 7,000 acres, serves as a laboratory for
state-of-the-art conservation practices. The National Arboretum in Washington, DC, managed by USDA's Agricultural
Research Service, sits on more than 440 acres and is intensively managed for horticultural purposes. USDA
manages additional smaller sites around the watershed and provides technical assistance for agricultural practices on
small acreages of federal lands managed by other agencies.
Chapter 2. Agriculture 2-3
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
area of animal feeding operations (AFOs). It is important to note that planning and implementing
successful conservation or control measures depends on site-specific considerations and
information. Consequently, the practices and actions presented here are a general guide to
inform development of more detailed plan or approach tailored to a specific facility, activity, or
location.
This chapter does not address the management of agricultural lands to protect and restore
water quality by reducing impacts from pesticides and from irrigation; for information on those
subjects, see the chapters devoted to those activities in the National Management Measures for
the Control ofNonpoint Pollution from Agriculture (USEPA 2003). This chapter does not
thoroughly cover losses of N to air, but it does provide some information on volatilization
controls. Finally, while recognizing the need to create new markets and alternative manure
uses, this chapter does not cover the emerging technologies and financial mechanisms that are
being developed to address those needs.
1.1.2 Intended Audience
The primary audience for this document is land managers in federal agencies who are
responsible for meeting water quality goals and implementing water quality programs on
agricultural land. In addition, State and local agencies may use this guidance in developing
Watershed Implementation Plans to meet water quality goals. Others who can benefit from the
information in this document include conservation districts; the agricultural services community;
farm owners, operators, and managers; local public officials responsible for land use and water
quality decision making; environmental and community organizations; and the business
community.
1.1.3 Water Quality Significance of Agricultural Runoff in the
Chesapeake Bay Watershed
Agriculture is the single largest source of nutrients and sediments to the Chesapeake Bay, and
according to the Chesapeake Bay model, it is responsible for approximately 43 percent of the N,
approximately 45 percent of the P, and approximately 60 percent of the sediment loads. Much
of that load is delivered from Pennsylvania (Susquehanna River), Virginia (Shenandoah and
Potomac rivers), and the Delmarva Peninsula of Maryland, Delaware, and Virginia. Chemical
fertilizer accounts for 17 percent of the N and 19 percent of the P load, and manure accounts for
19 percent of the N and 26 percent of the P load. Seven percent of the total nitrogen (TN) load
comes from air deposition from livestock and soil emissions from agriculture.
Implementing agricultural management practices might not provide nutrient load reductions to
the Chesapeake Bay as quickly as implementing actions by other sectors; however, reductions
2-4 Chapter 2. Agriculture
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
in agricultural loads are the most cost-effective means to restore the Bay over time. Excess N
from cropland is transported to the Bay via groundwater with a lag time of years or decades,
depending on the location in the watershed. Additionally, reductions in P loads from agricultural
lands might not be seen immediately after implementing P-control practices because of current
P saturation in cropland soils in areas with high animal densities. Protecting the Bay and its
watershed is costly and will require a variety of cost-share and economic support measures as
the next generation of tools and practices are expanded.
Historical Context of Agricultural Land in the Chesapeake Bay Watershed
Since European settlement, agriculture has played an important role in sustaining the people of
the Chesapeake Bay watershed. In the 1650s, the land was first broadly cleared for timber and
agriculture. The land was able to support the growing population and in the 1700s, as
agriculture expanded, the first signs of environmental degradation were noted. By the 1750s,
20 to 30 percent of the forested areas were stripped for settlement, and the shipping ports
began to fill with eroded sediment. By the 1800s, plows were used widely in agriculture,
beginning the widespread use of tillage, preventing reforestation and encouraging soil erosion.
In the first half of the 1800s, the Chesapeake and Delaware canal project encouraged even
broader expansion of agriculture. Half of the forests were cleared for agriculture and settlement,
wetlands were drained, and the first imported fertilizers (bird guano) were introduced from the
Caribbean and from nitrate (NO3) deposits on the northern Chilean coast.
Agriculture in the Chesapeake Bay Watershed Today
Immediately following World War II, chemical fertilizer use became widespread, and as
suburban expansion began in the 1950s, wetlands continued to be drained and filled. In the
1980s, nutrient management efforts began to take hold in agriculture, and in the 1990s,
Chesapeake Bay tributary strategies were put in place, setting goals for reductions of nutrient
and sediment loadings to the Bay. Today, for assessment purposes, the Bay and its tidal
tributaries are broken into 92 segments. The states have identified those segments as being
impaired because they do not meet water quality standards, and a total maximum daily load
(TMDL) will be prepared for each of the segments, collectively adding up to the Chesapeake
TMDL. A TMDL is a calculation of the maximum amount of a pollutant that the Bay can receive
and still safely meet water quality standards.
Approximately 25 percent of the land in the Chesapeake Bay watershed is used for agriculture.
Some practices used to maximize crop yields can cause deterioration in the quality of the Bay
and its watershed. Improperly applied fertilizers and pesticides can flow off the land and deliver
excess N, P, and chemicals to the Bay. The nutrients and bacteria in animal manure, which is
used for fertilizer, can seep into groundwater and run into waterways if managed improperly
Chapter 2. Agriculture 2-5
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
on site at an AFO or off-site on cropland or elsewhere. Poor tilling and irrigation practices can
promote erosion and can lead to additional sediment loads being delivered to waterbodies. The
outflow of the tile or the edge of drain creates a high potential for loss of streamside vegetation
and sediment scouring (see chapters 5 and 7). Those practices can be improved, enhanced, or
modified as appropriate to reduce pollutant loads from agriculture throughout the Chesapeake
Bay watershed. Also, an imbalance of nutrients in the Chesapeake Bay watershed must be
addressed through agriculture.
1.1.4 Managing Agricultural Runoff to Reduce Nutrient and Sediment
Loss
Recommended Water Pollution Control Strategy: Implement Next
Generation of Tools and Actions
To reach the Bay goals, the Chesapeake Bay Executive Order calls for implementation of the
next generation of tools and actions (Chesapeake Bay Program Office 2010). While nutrient
management planning (NMP) has been a part of farm operations since the 1980s because of
state program requirements, this document presents a description of the next generation of
NMP based on state-of-the-art science and understanding of the farm landscape today. The
NMPs will provide a strong link between production, nutrient management on the land, and
water quality. The NMPs described in this document will enable producers to achieve their
expected yields and reduce waste of the valuable, finite resources of nutrients and sediments,
while reducing the losses of the nutrients and sediments to surface water that eventually enters
the Chesapeake Bay.
Although agriculture is a key part of the solution to the Chesapeake Bay restoration given the
magnitude of loads and the relative cost-effectiveness of practices, we must overcome
significant barriers to reach broad-scale implementation in agriculture. While the draft Executive
Order section 203 Federal Strategy notes that restoration of the Chesapeake Bay or its
watershed is not expected for many years, restoration will require a renewed commitment and
therefore actions taken throughout the agricultural landscape will need to become more
strategic, coordinated, and goal-oriented to meet the Bay goals (Federal Leadership Committee
2009).
The most significant improvement in agricultural production needed to restore the Chesapeake
Bay is to change how excess manure nutrients are handled. Therefore, the major focus of this
chapter is on nutrient management, accompanied by practices and actions for AFO production
areas as well as sediment and erosion control on cropland. The practices, taken together, can
greatly reduce the introduction of nutrients to the Chesapeake Bay.
2-6 Chapter 2. Agriculture
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
The most effective practices to reduce pollution inputs of nutrients to the Chesapeake Bay focus
around controlling the rate, timing, method and form of nutrient application. This guidance
presents the implementation measures component of NMPs that would maximize reductions by
agriculture. The current practices in the Chesapeake Bay watershed being reported by states
should be expanded. The Chesapeake Bay Program Office has compiled a great deal of
information on the effectiveness of those practices,
http://www.chesapeakebay.net/marylandbmp. aspx?menuitem=34449.
Achieving Multiple Benefits
The benefits and services provided by well-managed agriculture in the Chesapeake Bay
watershed are numerous and include sustained crop yields; restored waterbodies for drinking
water, recreational, and other beneficial uses; habitat benefits; a functioning ecosystem;
reduced vulnerability to invasive species; and a continued healthy and productive agricultural
economy in the Chesapeake Bay watershed. When effective land cover from agriculture occurs
year-round, those systems can store carbon and minimize soil erosion that fills local waters and
the Bay. A healthy agricultural network in the Bay watershed will provide for key connections
across the landscape for animals and birds, as well as reduce the watershed's vulnerability to
flooding and the effects of climate change.
Readers of this chapter should also see Chapters 4 and 5 regarding Forestry and Riparian
Buffers. While this chapter focuses on source control and treatment options for cropland and
animal production areas in agriculture, it is essential that a holistic restoration of the
Chesapeake Bay watershed also achieve the benefits that can be reaped when all these
systems are operating together to serve the watershed.
1.2 Overview of the Agriculture Chapter
This chapter provides recommendations in the form of implementation measures for the suite of
practices that can be implemented on agricultural lands. While these recommendations are
made from state-of-the-art literature, the chapter expands on the National Management
Measures to Control Nonpoint Pollution from Agriculture (USEPA 2003).
Information on the effectiveness of practices included in this chapter is largely taken from
literature published after 2000 to build on the earlier literature that was used in developing the
National Management Measures to Control Nonpoint Pollution from Agriculture (USEPA 2003).
For some practices, however, the literature search went back further in time. This includes, for
example, drainage water management, a practice not addressed to a significant extent in EPA's
2003 guidance. The bulk of literature used in this chapter comes from professional journal
publications (e.g., Journal of Environmental Quality), but information is also derived from
Chapter 2. Agriculture 2-7
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
government documents and resources (e.g., USDA conservation practice standards), books,
Cooperative Extension publications, proceedings from professional meetings, and online
publications by professional groups and industry. Most literature was found through keyword
searches of sources such as the National Agricultural Library Catalog and specific professional
journals. Literature specific to the Chesapeake Bay watershed states was given top priority, but
relevant literature from across the United States and from other countries was included to
provide as complete coverage as possible on each of the topics addressed in this chapter.
Practice cost data taken from the literature and other sources were converted to 2010 dollars
using the conversion factors provided by the U.S. Inflation Calculator (2010). Exceptions are
that cost data provided for fiscal year 2010 by states were not changed, and aggregate cost
data expressed over a range of years were not converted to 2010 dollars. Unless specified, the
year of publication was used as the initial year for conversion of dollars.
1.2.1 Management Practices and Management Practice Systems
To best plan and implement practices that will benefit water quality, producers should have in
place a conservation plan. A conservation plan based on an evaluation of the soil, water, air,
plant, and animal resources should present the practices, tools, and actions that will be used on
the agricultural land to benefit water quality. This plan outlines the management practices to be
implemented and maintained.
Management practices are implemented on agricultural lands for a variety of purposes,
including protecting water resources, human health, terrestrial or aquatic wildlife habitat, and
land from degradation by wind, salt, and toxic levels of metals. The primary focus of this
guidance is on agricultural management practices that reduce the delivery of pollutants into
water resources by reducing pollutant generation or by remediating or intercepting pollutants
before they enter water resources. This guidance generally refers to the term management
practice, and this encompasses all agricultural practices, including structural, cultural, and
traditional management practices.
The Natural Resources Conservation Service (NRCS) maintains a National Handbook of
Conservation Practices (USDA-NRCS 1977), updated continuously, which details nationally
accepted management practices. Those practices are on the USDA-NRCS Web site at
http://www.nrcs.usda.gov/technical/efotg/. Each state adopts and tailors those standards to
meet state and local conditions and criteria, and the state-adopted standards could be more
restrictive than the national criteria referenced in this guidance. In addition to the NRCS
standards, many states use locally determined management practices that are not reflected in
the NRCS handbook. Note that while a wide variety of practices are available, all require regular
inspection and maintenance to ensure continued performance at expected levels. Readers
2-8 Chapter 2. Agriculture
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
interested in obtaining information on management practices used in their area should contact
their local Soil and Water Conservation District or local USDA office. Two very helpful
handbooks are 60 Ways Farmers Can Protect Surface Water (Hirschi et al. 1997), and 50 Ways
Farmers Can Protect their Ground Water (Hirschi et al. 1993).
Management practices are used to control a pollutant type from specific land uses. For
example, conservation tillage is used to control erosion from irrigated or non-irrigated cropland.
Management practices can also provide secondary benefits by controlling other pollutants,
depending on how the pollutants are generated or transported. For example, practices that
reduce erosion and sediment delivery often reduce P losses because P is strongly adsorbed to
silt and clay particles. Thus, conservation tillage reduces erosion and reduces transport of
particulate P.
In some cases, a management practice can provide environmental benefits beyond those linked
to water quality. For example, riparian buffers, which reduce P and sediment delivery to
waterbodies, can also serve as habitat for many species of birds and plants where the design
and width provide for this use.
Sometimes, however, management practices used to control one pollutant might inadvertently
increase the generation, transport, or delivery of another pollutant; management practices
should be implemented through a systems approach to ensure balance. Conservation tillage,
because it creates increased soil porosity (i.e., large pore spaces), can increase water transport
through the soil. Without crop growth and the associated root system that would take up
available N, increased water transport through the soil can also lead to increased N leaching
particularly where fertilizer N is applied not as part of the management plan that accounts for the
timing and amount of crop N needs. Tile drains, used to reduce surface runoff and increase soil
drainage, can also have the undesirable effect of concentrating and delivering N directly to
streams (Hirschi et al. 1997). To reduce the N pollution caused by tile drains, other
management practices, such as nutrient management for source reduction, cover crops and
biofilters that treat the outflow of the tile drains, might be needed. On the other hand, practices
that reduce runoff might contribute to reduced in-stream flows, which have the potential to
adversely affect habitat. Therefore, management practices should be chosen only in the context
of a holistic evaluation of both the benefits and potential adverse effects of the suite of practices,
or management system, to be implemented at a site.
Some management practice systems include both repetitive treatment by the same practice at
different places in a field as well as diversification of practices to enhance all the benefits of
each. An example of such a system is an animal waste management system in which some
components are included to help others function. For example, diversions and subsurface
drains might be necessary to convey runoff and wastes to a waste treatment lagoon for
Chapter 2. Agriculture 2-9
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
treatment. While the diversions and subsurface drains might not provide any measurable
pollution control of their own, they are essential to the overall performance of the animal waste
management system. Other components, such as lagoons and waste utilization plans, are
added to provide repetitive treatment.
Note on Practice Effectiveness: The effectiveness of any management practice is a function of a
variety of factors including the characteristics of the baseline condition (e.g., influent water
quality, soil nutrient levels, and current management practices), slope, soil type, climate, crops,
and weather conditions during the study. Further, the monitoring and assessment approach
used in a study imparts significant limitations to interpreting the findings. For example, inflow-
outflow studies can be used to assess pollutant removal but only if the outflow and inflow
measurements pertain to the same parcel of water. Load and concentration reductions have
different meanings and utility, and it is particularly important to have full understanding of the
comparison or benchmark against which the reduction is measured. This chapter's summary of
literature findings on the effectiveness of agricultural management practices and systems must
be interpreted carefully, and EPA strongly recommends that the reader review full reports before
applying the findings to any specific situation, because the information presented represents
general examples applicable to the site and situation studied and the effects of conservation
tools and approaches applied depends on a number of variables site specific to the farm
operation.
This chapter is divided into three sections regarding specific control options. Three types of
practices are necessary in agricultural production to control nutrients and sediments; through
these types of practices, the path of nutrients and sediment can be controlled. These three
types avoid, control, and trap pollutants (ACT), and practices that suit each should be
implemented in agricultural production.
• Section 2: Nutrient and sediment source control and avoidance from cropland and
animal production areas
• Section 3: Cropland in-field controls
• Section 4: Cropland edge-of-field trapping and treatment
This guidance separately discusses source control and avoidance practices for the two critical
topics of cropland agriculture and animal agriculture. However, the link between ensuring
adequate storage and developing appropriate land application practices is one of the most
critical considerations in successfully developing and implementing a site-specific nutrient
management plan for manure, litter and process wastewater on animal agriculture operations
that rely on cropland agriculture. Therefore, while the specific management practices are
separately discussed in this guidance, it should be understood that those two aspects of
2-10 Chapter 2. Agriculture
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
agriculture are intricately linked and must be implemented through a systems approach to
ensure a reduction in nutrient delivery to the Bay watershed.
Controlling the sources of nutrients and sediment entering the Chesapeake Bay through a
variety of approaches at the field or production area, farm, and watershed scale will minimize
the pollutants available throughout the agricultural operation. Source control and avoidance
pertains to a crop's ability to use the nutrients available throughout the growing season,
cropping cycles, feed management, manure management, and chemical fertilizer management.
Source control approaches for cropland carefully evaluate the proper rate, timing, method, and
form of nutrient application.
The cropland in-field controls focus on nutrient and sediment controls throughout the field itself.
In-field practices will impede the transport or delivery (or both) of pollutants, either by reducing
water transported, and thus the amount of the pollutant transported, or by transforming the
pollutant into less harmful forms into the soil or atmosphere.
Wetlands, drainage water management, and buffers and setbacks are examples of important
edge-of-field or end-of-pipe measures to prevent nutrient loads to the Chesapeake Bay.
This chapter presents a set of implementation measures that are organized by the pathway in
which nutrient and sediment controls can be implemented. While the implementation measures
are discussed independently from one other, they are intended to be implemented together as a
comprehensive management system. The implementation measures are organized into the
three components of source control and avoidance, in-field control, and edge-of-field trapping
and treatment. The specific set of practices to be chosen by an agricultural producer to achieve
pollutant reductions will necessarily be tailored as appropriate on the basis of a variety of factors
related to the landscape, agricultural operation, and other similar factors; the practices chosen
should link controls at the source, in the field, and at the edge of the field.
Chapter 2. Agriculture 2-11
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
1.2.2 Implementation Measures for Agriculture in the Chesapeake
Bay Watershed to Control Nonpoint Source Nutrient and
Sediment Pollution
Source Control and Avoidance
Cropland Agriculture
Implementation Measures:
A-l. Base P application on P saturation in soils as follows:
• If the soil P saturation percentage is above 20 percent, do not apply
manure or commercial fertilizer that contains P to cropland, grazing or
pasture land.
• When soil P saturation percentage allows for application (i.e., is below
20 percent saturation), apply up to an N-based rate.
• Also, implement a soil P monitoring plan to ensure that soil-P levels are
staying steady over time.
• If soil P saturation percentage is increasing, adjust manure applications
to P-based rate and use commercial N fertilizer to make up the
difference; if levels exceed 20 percent P saturation, no longer apply P.
A-2. Maximize N fertilizer use efficiency to maximize the net benefit from the
lowest-needed amount of manure, biosolids, or commercial N fertilizer
entering the cropland system. Whenever N fertilizer is applied where
manure has already been applied, reduce N fertilizer rates according to the
N credit of the manure that was applied. That N credit will vary depending
on the amount, timing, type, and method of manure that was applied.
A-3. Replace high nutrient loading crops in high-risk areas for water quality
effects with sound alternatives.
A-4. (1) Retire highly erodible lands (HELs) from cropland and replace the crop
with perennial native vegetation, or (2) develop and implement a soil
conservation plan to reduce sheet and rill erosion to the Soil Loss Tolerance
Level (T) as well as a nutrient management plan.
A-5. When using commercial fertilizer, give credit for manure nutrients. When
commercial fertilizer is used, provide for the proper storage, calibration, and
operation of chemical fertilizer nutrient application equipment.
2-12 Chapter 2. Agriculture
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
Animal Agriculture
Implementation Measures:
A-6. Formulate animal feeds to reduce nutrient concentration in manure,
improve the manure N:P ratio in relation to crop needs, and/or eliminate
toxic substances such as arsenic in manure used as fertilizer. Align the N:P
ratio of the manure to be equal to (or greater than) the N:P ratio of the crop
need.
A-7. Safely and strategically apply (with properly calibrated equipment), store,
and transport manure.
• Liquid manure storage systems including tanks, ponds, and lagoons
(e.g., NRCS Practice Code 313 Waste Storage Facility) should be designed
and operated to safely store the entire quantity and contents of animal
manure and wastewater generated, contaminated runoff from the
facility, and the direct precipitation from events in the geographic area,
including chronic rain.
• Dry manure (i.e., stackable, greater than or equal to 20 percent dry
matter), such as that produced in poultry and certain cattle operations,
should be stored in production buildings, storage facilities, or otherwise
covered to prevent precipitation from coming into direct contact with the
manure and to prevent the occurrence of contaminated runoff. When
necessary, temporary field storage of dry manure (e.g., poultry litter)
may be possible under protective guidelines (e.g., NRCS Practice Code
633 Waste Utilization).
• For manure and litter storage, the AFO should maintain sufficient
storage capacity for minimum critical storage period consistent with
planned utilization rates or utilization practices and schedule.
A-8. Exclude livestock from streams and streambanks and provide alternative
watering facilities and stream crossings to reduce nutrient inputs,
streambank erosion, and sediment inputs and to improve animal health.
A-9. Process/treat through physical, chemical, and biological processes facility
wastewater and animal wastes to reduce as much as practicable the volume
of manure and loss of nutrients.
Chapter 2. Agriculture 2-13
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
Cropland In-Field Control
Implementation Measures:
A-10. Manage nutrient applications to cropland to minimize nutrients available for
runoff. In doing so
• Apply manure and chemical fertilizer during the growing season only
• Do not apply any manure or fertilizer to saturated, snow-covered, or
frozen ground
• Inject or otherwise incorporate manure or organic fertilizer to minimize
the available dissolved P and volatilized N
• Apply nutrients to HELs only as directed by the nutrient management
plan, while at the same time implementing all aspects of the soil
conservation plan
A-ll. Use soil amendments such as alum, gypsum, or water treatment residuals
(WTR) to increase P adsorption capacity of soils, reduce desorption of water-
soluble P, and decrease P concentration in runoff.
A-12. Use conservation tillage or continuous no-till on cropland to reduce soil
erosion and sediment loads except on those lands that have no erosion or
sediment loss.
A-13. Use the most suitable cover crops to scavenge excess nutrients and prevent
erosion at the site on acres that have received any manure or chemical
fertilizer application. Cover crops should be used during a non-growing
season (including winters) or when there is bare soil in a field.
A-14. Minimize nutrient and soil loss from pasture land by maintaining uniform
livestock distribution, keeping livestock away from riparian areas, and
managing stocking rates and vegetation to prevent pollutant losses through
erosion and runoff.
A-15. Where drainage is added to an agricultural field, design the system to
minimize the discharge of N.
2-14 Chapter 2. Agriculture
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
Cropland Edge-of-Field Trapping and Treatment
Implementation Measures:
A-16. Establish manure and chemical fertilizer application buffers or minimum
setbacks from in-field ditches, intermittent streams, tributaries, surface
waters, open tile line intake structures, sinkholes, agricultural well heads, or
other conduits to surface waters.
A-17. Treat buffer or riparian soils with alum, WTR, gypsum, or other materials to
adsorb P before field runoff enters receiving waters.
A-18. Restore wetlands and riparian areas from adverse effects. Maintain nonpoint
source abatement function while protecting other existing functions of the
wetlands and riparian areas such as vegetative composition and cover,
hydrology of surface water and groundwater, geochemistry of the substrate,
and species composition.
A-19. For both new and existing surface (ditch) and subsurface (pipe) drainage
systems, use controlled drainage, ditch management, and bioreactors as
necessary to minimize off-farm transport of nutrients.
A-20. Manage runoff from livestock production areas under grazing and pasture
to minimize off-farm transport of nutrients and sediment.
Chapter 2. Agriculture 2-15
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
2 Implementation Measures and Practices for
Source Control and Avoidance
2.1 Cropland Agriculture
2.1.1 Nutrient Imbalance in the Chesapeake Bay Watershed
In the Chesapeake Bay watershed, the overall delivery of agriculture-based nutrients to the Bay
needs to decrease significantly to protect the quality of the Chesapeake Bay. Unfortunately, a
significant nutrient imbalance exists in the Bay watershed. More P is produced and imported
into the watershed than is needed to fertilize crops, resulting in the imbalance and excess N and
P available for delivery to the Bay through surface and ground waters. Nationwide, 1997 USDA
estimates show that most U.S. counties (78 percent) need to move manure P from at least
some animal operations to avoid P accumulation. Also, 1997 USDA estimates show that poultry
operations account for two-thirds of N on farms and half of the excess P because generally,
poultry litter has a high P-content, and poultry operations have less land than other operations
for application. Dairy and hog operations also contribute to excess on-farm P. While manure as
fertilizer does provide benefits to the soil in the form of amendments and carbon, the controlled
use of manure is imperative to protecting water quality in the Bay watershed.
The Mid-Atlantic Water Program (MAWP), a consortium of land grant universities in the
Chesapeake Bay watershed, developed nutrient budgets and balances by county and state for
2007 (MAWP 2007). Nutrient budgets are, "a summary of the major nutrient inputs and outputs
to the cropland in a geographic region." Nutrient balances are defined as "the difference
between nutrient inputs and outputs." When the nutrient balance is close to zero, nutrients
applied from manure and commercial fertilizer are closely matched to crop use. When the
nutrient balance is positive, nutrient inputs exceed outputs and excess nutrients are available
that can reach the Bay. When the nutrient balance is negative, nutrient outputs exceed inputs.
The MAWP also developed maps, in which nutrient input equals the amount of manure and
fertilizer nutrient available for application, and nutrient output is determined by the amount of
nutrient taken up by the crop, measured in the plant biomass harvested. The maps do not
account for the level of nutrients that are already in the soil before application of additional
nutrient inputs and also do not account for the N and P chemical fertilizers that are applied to
crops annually; however, in places where there is a zero balance and it might seem that
nutrients are being appropriately managed, high soil nutrients are available in those areas that
could lead to nutrient loss to the Bay because P-saturation is not part of the consideration. The
analysis identifies three such hotspots in the Chesapeake Bay watershed: the Shenandoah
2-16 Chapter 2. Agriculture
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
River Valley in Virginia, the Eastern Shore of Maryland, and Lancaster County and surrounding
areas in Pennsylvania (Figures 2-1 and 2-2).
2007
N balance (tons)
(2445)-(51)
(50)-121
122-592
593-1333
1334-27155
Source: MAWP 2007, Note: The darkest color indicates counties with the highest N balances.
Figure 2-1. The map shows the N balance for cropland in Mid-Atlantic counties in 2007.
2007
P balance (tons)
State Boundaries
-300 - 0
0-1000
1001-2000
2001 - 3000
3001 -10000
Source: MAWP 2007, Note: The darkest color indicates counties with the highest P balances.
Figure 2-2. The map shows the P balance for cropland in Mid-Atlantic counties in 2007.
Chapter 2. Agriculture
2-17
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
Realistic production goals should guide nutrient rate reductions in agriculture and are critical for
reducing N and P export from agricultural lands and moving toward a nutrient-balanced
Chesapeake Bay watershed. The current model for nutrient use maximizes plant uptake by
saturating nutrients through application, especially for N; this should be adjusted to account for
non-optimum weather patterns. Because optimum weather conditions occur on average once
every 5 to 7 years, an excess of N and P is in the fields in most years (those with non-optimum
weather).
The following section details practices and actions that can minimize excess nutrients from
entering the agricultural production system and achieve a nutrient balance.
2.1.2 Nutrient Management
The management tools and practices in widespread use in the Chesapeake Bay watershed for
both organic (manure, sludge, and such) and inorganic (commercial fertilizer) nutrient
application are insufficient to prevent over-application and the resulting nutrient loading to the
Chesapeake Bay. However, NMP in line with those implementation measures, if broadly applied
in the watershed, will significantly reduce nutrients available as runoff into local waters and the
Chesapeake Bay. Controlling the rate of nutrient application is the first defense to limiting the
amount of nutrients that might be able to leave the land throughout the production process.
The goals of NMP are to apply nutrients at rates necessary to achieve realistic crop yields,
improve the timing of nutrient application, employ appropriate tools to determine application
rate, method and form (manure or inorganic), and to reduce the risks of nutrients moving from
the land and production area to local waters. When manure is the source of fertilizer, both the
nutrient value and the rate of availability of the nutrients should be determined. With commercial
fertilizer, that information is on the label. Where legume crops (e.g., soybeans) are planted, the
N contribution of the crop should be determined and credited to the following crop.
NMP is implemented to increase the efficiency with which crops use applied nutrients, thereby
reducing the amount available to be transported to both surface and ground waters. Controlling
nutrient inputs (source) by practicing effective nutrient management is imperative, and reducing
the nutrient inputs to the agricultural system will effectively minimize nutrient losses from
cropland occurring at the edge-of-field by runoff and by leaching from the root zone. Once N, P,
or other nutrients are applied to the soil, their movement is largely controlled by the movement
of soil and water and must therefore be managed through other control systems such as erosion
control and water management. That is usually achieved by developing a nutrient budget for the
crop, applying nutrients at the proper time with proper methods, applying only the types and
amounts of nutrients necessary to produce a crop, and considering the environmental hazards
of the site. In cases where manure is used as a nutrient source, manure storage will be needed
2-18 Chapter 2. Agriculture
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
to provide capability to apply manure at optimal times. Even with proper nutrient management,
rain can cause nutrients to move into waterways if the rain is heavy, frequent, or comes soon
after nutrient applications. Therefore nutrient management needs to be supplemented with in-
field and edge-of-field controls.
In many instances, NMP results in using lower application rates of commercial fertilizer because
of the availability of manure nutrients and, therefore, a reduction in production costs. However
the agriculture system in the watershed has a general imbalance of nutrients due to excess
manure generated annually by the combination of all AFOs in the watershed. Thus, for any
cropland where there has not been a balanced use of nutrients in the past, NMP should
incorporate the options for source control presented in this section—the reduction of nutrients
for input into the agricultural production system—to reduce the possibility of excess nutrients
being applied out of need to reduce capacity of manure.
Nutrient management planning should consider all aspects of the rate, timing, method, and form
of nutrients, consistently using the host of data available through effective use of nutrient use
tools. Nutrient management plans typically focus on N and P, the nutrients of greatest concern
for water quality, and it is important to consider all sources of those nutrients as input to the
agricultural system. The major sources of nutrients include the following:
• Commercial fertilizers
• Manures, sludges, and other organic materials
• Crop residues and legumes in rotation
• Irrigation water
• Atmospheric deposition of N
• Soil reserves
Good and strategic NMP can significantly reduce costs. For example when manure is used, the
total cost of a nutrient management system are those costs associated with manure nutrient
application, plus the disposal of alternative use cost for manure that cannot be applied within a
reasonable local transport area, less the savings incurred by reduced commercial fertilizer.
Maximizing the nutrient use efficiency (NUE), the measure of how much crop is produced per
unit of nutrient supplied, should always be a part of NMP. A greater NUE of a crop leaves less N
and P available for transport to waterbodies. NUE consists of two main components:
• Crop removal efficiency or the removal of nutrient in a harvested crop as a percent of
nutrient applied to the crop (Mosier et al. 2004)
• The increase in residual nutrients available to the crop from the soil (Ladha et al. 2005)
Chapter 2. Agriculture 2-19
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
Because N and P behave very differently, basic understanding of how N and P are cycled in the
soil-crop system is an important foundation for effective nutrient management. The National
Management Measures to Control Nonpoint Pollution from Agriculture (USEPA 2003) is an
excellent source describing the technical details of each of the nutrient sources and cycles in
agriculture. Figures 2-3 and 2-4 depict the N and P cycles, respectively.
Atmospheric
Nitrogen
(legume plants) (commercial fertilizer)
Animal & Plant Uptake by All
Plants
Leaching Loss
Figure 2-3. The N cycle.
2-20
Chapter 2. Agriculture
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
Available
Soil
Phosphorus
Figure 2-4. The P cycle.
N is continually cycled among plants, soil organisms, soil organic matter, water, and the
atmosphere in a complex series of biochemical transformations. Some N forms are highly
mobile, while others are not. At any time, most of the N in the soil is held in soil organic matter
(decayed plant and animal tissue) and the soil humus. Regeneration processes slowly transform
the N in soil organic matter by microbial decomposition to ammonium ions (NH4+), releasing
them into the soil where they can be strongly adsorbed and kept relatively immobile. Plants can
use the ammonium, however, and it can be moved with sediment or suspended matter.
Nitrification by soil microorganisms transforms ammonium ions (either mineralized from soil
organic matter or added in fertilizer) to nitrite (NO2-) and then quickly to nitrate (NO3-), which is
easily taken up by plant roots. NO3, the form of N most often associated with water quality
problems, is soluble and mobile in water. Plant uptake includes processes by which ammonium
and NO3 ions are converted to organic-N, through uptake by plants or microorganisms, and by
binding with the soil. Denitrification converts NO3 into nitrite (NO2) and then to nitrous oxide
(N2O) and gaseous N through microbial action in an anaerobic environment. Volatilization is the
loss of ammonia gas (NH3) to the atmosphere.
An N atom can pass through the cycle many times in the same field. The processes in the N
cycle can occur simultaneously and are controlled by soil organisms, temperature, and
availability of oxygen and carbon in the soil. The balance among the processes determines how
much N is available for plant growth and how much will be lost to groundwater, surface water, or
the atmosphere.
P lacks an atmospheric connection (although it can be transported via airborne soil particles)
and is much less subject to biological transformation, rendering the P cycle considerably
Chapter 2. Agriculture
2-21
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
simpler. Most of the P in soil occurs as a mixture of mineral and organic materials, and P exists
largely in a single valence state, unlike N. A large amount of P (50-75 percent) is held in soil
organic matter, which is slowly broken down by soil microorganisms. Some of the organic P is
released into soil solution as phosphate that is immediately available to plants. The phosphate
released by decomposition or added in fertilizers is strongly adsorbed to soil particles and is
rapidly converted into forms that are unavailable to plants. The equilibrium level of dissolved P
in the soil solution is controlled by the chemical environment of the soil (e.g., pH, oxidation-
reduction, iron and aluminum concentration) and by the P content of the soil. Plant-available P
is measured by varying methods, and this guidance references P measurements made with the
following extractable solutions: Mehlich 1, Mehlich 3, Bray 1, and modified Morgan.
Throughout the Chesapeake Bay watershed, those cycling processes are constantly occurring
throughout agricultural lands. To effectively plan, design, and implement controls, it is
imperative to understand these basic nutrient cycles.
Practice Costs
An analysis of the more than $3.5 billion spent toward nutrient controls in the Chesapeake Bay
watershed between 1985 and 1996 found that nutrient management (e.g., USDA-NRCS
Conservation Practice Code 590) was the least costly practice for nutrient control (Butt and Brown
2000). The estimated average unit cost in fiscal year (FY) 2010 for development and record
keeping for a comprehensive nutrient management plan in Virginia is $1,190 (USDA-NRCS 2010).
Phosphorus
Implementation Measure A-1:
Base P application on P saturation in soils as follows:
• If the soil P saturation percentage is above 20 percent, do not apply
manure or commercial fertilizer that contains P to cropland, grazing or
pasture land.
• When soil P saturation percentage allows for application (i.e., is below
20 percent saturation), apply up to an N-based rate.
• Also, implement a soil P monitoring plan to ensure that soil-P levels are
staying steady over time.
• If soil P saturation percentage is increasing, adjust manure applications
to P-based rate and use commercial N fertilizer to make up the
difference; if levels exceed 20 percent P saturation, no longer apply P.
2-22 Chapter 2. Agriculture
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
In the Chesapeake Bay watershed, where animal manure is a dominant and available source of
fertilizer, an overabundance of P exists, as described in Section 2.1.1.
Because P attaches to soil particles, P levels can build up in the soil, and the P saturation
(P-sat) percentage increases. (P-sat is a tool that can estimate the degree to which P sorbing
sites are saturated with P.) Thus, P fertilizer application is dependent on the existing soil P-sat
percentage. When P is attached to the soil, it poses a risk to water quality if soil erosion is not
controlled appropriately, because it will move off-site with the soil. For an environmental risk to
exist from P transport to surface waters, P must be in a form that can be released to water. The
P-sat percentage does not measure directly the risk for P loss in runoff; the P-sat percentage
indicates the amount of P that is desorbed and moved into solution when the soil comes into
contact with water (Kovzelove et al. 2010). This is only one mechanism by which P will be
released from a soil mineral. While P will cease to sorb to mineral surfaces if binding sites are
saturated, P can also be released if the sorbing complexes solubilize. Various environmental
conditions control the solubility of such complexes. For example, iron, when oxidized, forms
strong insoluble complexes with P, but if iron becomes reduced, the complex will solubilize and
release P. When P bound to soil sediments via iron complexes are eroded to surface waters,
the iron will become reduced and release P. While this is one pathway for P to move into the
water solution if there are no more places for P to bind to on the mineral, there are other
pathways for loss as well.
Butler and Coale (2005) describe how the amount of P released from soil when in contact with
water increases exponentially once the P-sat percentage is between 20-30 percent (Figure 2-5).
Soil Test P:
200ppm or
400lb/acre
•Keyport sandy loam
Donlonton sandy
loam
Matapcakc siltloam
50 75 100
Degree of P Saturation (%}
Pox/0.5(Feox+Alox)
125
Source: adapted from Butler and Coale 2005
Figure 2-5. The chart shows the relationship between P-saturation
and dissolved P release to water.
Chapter 2. Agriculture
2-23
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
EPA recommends that P fertilizer not be applied to soils that are above 20 percent where P
desorption and loss as runoff can occur. In addition, it is important for the nutrient management
plan to address the slope and movement patterns for water as runoff in a field by implementing
cropland in-field controls (as described below in Section 3 of this chapter), because P-sat
percentage does not dictate the probability of P in runoff to move to a ditch or local waterbody.
Tools can be used to plan for the applicable rate, timing, form, and method of P fertilizer
application. Understanding P-sat percentages in soils throughout the field is necessary to
ensure that the farmer is not applying P that is above the level needed for the crop and dually
affecting water quality. When testing for soil P, depth of measurement below the surface is an
important consideration, to account for buildup on the surface when manure is applied (but not
incorporated); a host of soil P of testing options are available, including Mehlich 1, Mehlich 3,
Bray 1, and modified Morgan, all of which must be fully understood because they are not
immediately exchangeable. P-sat percentage calculations can be implemented with the
assistance of USDA-NRCS staff, extension agents, Technical Service Providers (TSPs), or
other private industry consultants and researchers.
Beck et al. (2004) have calculated for three major physiographic regions of Virginia the degree
of P-sat as a function of Mehlich 1 extractable P for soils. That calculation provides a useful
model that can be adopted throughout the Chesapeake Bay watershed. Future research should
include calculation of the degree of P-sat in major soil types, starting in the areas of the Bay
watershed where there is a significant P imbalance (Figure 2-2).
Nitrogen
Implementation Measure A-2:
Maximize N fertilizer use efficiency to maximize the net benefit from the lowest-
needed amount of manure, biosolids, or commercial N fertilizer entering the
cropland system. Whenever N fertilizer is applied where manure has already been
applied, reduce N fertilizer rates according to the N credit of the manure that was
applied. That N credit will vary depending on the amount, timing, type, and method
of manure that was applied.
The NUE should be maximized to the extent practicable, and the expected NUE based on the
tests described here should be incorporated into the NMP. A host of tools can assist nutrient
management planners in developing the N application rate on the basis of in-field variability. By
using tools to increase crop NUE, N loss is minimized through reductions in leaching, surface
flow, ammonia volatilization, nitrification and denitrification, and soil erosion by calibrating the N
2-24 Chapter 2. Agriculture
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
input to the yield potential and crop needs. NUE is maximized to reduce N loss when the crop-
removal efficiency (the efficiency of the crop to take in all N made available to it) works in
tandem with the increase in residual nutrients available from the soil during the time the crop is
growing.
Use of N use efficiency tools reduces over-applied N from leaving the production field and
entering local waterways. Good N use efficiency is critical because higher use efficiency
reduces the level of excess N available to create potential environmental problems, especially
after the fall crop harvest during groundwater recharge events.
Improving the N application rate of a nutrient management plan for any cropland should use
NUE tools as a guide through a series of steps to determine the rate, realistic production goals,
and precision/decision agriculture systems and tools to efficiently apply N though improved
materials, timing, placement, and use. A variety of in-field tests can be used to adjust inputs to
meet the optimum yield of the plant in a manner in which N loss to the environment is
minimized.
Maryland and Delaware have determined a suite of tools that make up a decision agriculture
program, and other states in the Chesapeake Bay watershed are actively considering similar
approaches; a broad range of effective tools can be used where applicable. The tools have
varying degrees of technical needs and can all be implemented with the assistance of NRCS,
extension agents, TSPs, or other private industry consultants and researchers. Many of the
tools can be implemented at a scale broader than the field level, so it can be financially
beneficial if neighboring smaller farms collaborate in implementation. Those include the
following decision agriculture tools (additional tools and references are in Appendix 2):
• Stalk nitrate tests for field corn production is one of the most accurate methods to
estimate N application rate for subsequent years when used over time to make better
and more confident N management decisions. The test is done at the end-of-season and
provides field specific data to know if the N available for crop uptake was deficient,
marginal, optimal, or in excess for the plant to produce the optimum yield. The results of
the test can be used to improve the NUE practice, and the NUE effectiveness is
enhanced when the results are shared among localized area farmers with comparable
cropland production conditions (Blackmerand Mallarino 1996).
• Crop testing is a broader approach for a wider diversity of crops than the stalk NO3 test.
Crop testing is used generally to detect the relative plant available N by sight with a leaf
color chart or chlorophyll meter, measuring plant available soil N with the Pre-Sidedress
Nitrate Test (PSNT) or employing real time chlorophyll measurement for variable rate
application in the field.
Chapter 2. Agriculture 2-25
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
• Fertilizer prescription rate maps can be a very useful NUE tool; they are developed
using strategic soil testing (e.g., PSNT) and global positioning system (GPS) crop yield
monitoring data. Soil tests are conducted throughout a field and GPS crop yield data
maps are joined, to chart the field variability of N availability, to determine realistic crop
production levels, and to help determine the subsequent season's appropriate nutrient
prescriptive application rates.
• To maintain existing soil fertility levels, crop nutrient removal can be used to measure
the difference between the application rate and the plant uptake rate. Simple charts can
be devised to employ this tool, or software programs are available to ease the
calculations.
• Aerial imagery and strip trials are effective individual tools, but when coupled at the
end of a season, can provide an effective means to understand the spatial variability of a
field remotely. This can also help identify field areas where there are signs of planter or
applicator skips, diseased or pest-damaged areas, weed infestations and other non-
uniform areas, which can decrease the amount of plant available N required to meet
crop needs. While strip trials are conducted throughout the season, aerial imagery is
generally done during the growth phase of the crop (as opposed to when the crop is
mature).
• Nutrient source integration is used generally with organic fertilizer (manure), as a part
of developing a manure management plan. This tool provides multiple benefits and is
used to determine subsequent season's manure needs and can simplify manure
application records.
• A tool being developed for the future is environmental risk assessment. It considers
the location of the field and its potential to impair local or far-field areas using known
transport factors.
2.1.3 Alternative Crops
Implementation Measure A-3:
Replace high nutrient loading crops in high-risk areas for water quality effects with
sound alternatives.
High-risk areas exist in places where there is intense animal agriculture because of the resulting
imbalance in nutrients (see Section 2.1.1). High nutrient loading crops, such as corn and
soybean, should be replaced with alternatives in environmentally sensitive areas such as those
in close proximity to local waters or in areas where there is a recorded nutrient imbalance for N
2-26 Chapter 2. Agriculture
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
or P. High risk areas include such agricultural lands as sandy soils, which allow for easy N
transport. When shifting high nutrient loading crops out of the sensitive areas, the viability and
market for the replacement crops will play an important role in deciding on which crops to grow.
Local agricultural contacts such as extension agents, conservation district staff, and TSPs can
provide the best assistance in choosing alternative crops while meeting production goals. In
Maryland, the document Alternative Agriculture in Maryland: A Guide to Evaluate Farm-Based
Enterprises (Musser et al. 1999) provides a workbook with 78 separate decision worksheets.
The USDA National Agricultural Library document Alternative Crops & Enterprises for Small
Farm Diversification (Gold and Thompson 2009) provides a broad range of information on
alternative crops.
2.1.4 Land Retirement
Implementation Measure A-4:
(1) Retire highly credible lands (HELs) from cropland and replace the crop with
perennial native vegetation, or (2) Develop and implement a soil conservation plan to
reduce sheet and rill erosion to the Soil Loss Tolerance Level (T) as well as a nutrient
management plan.
Highly erodible land (HEL) is defined by the Sodbuster, Conservation Reserve, and
Conservation Compliance parts of the Food Security Act of 1985 and the Food, Agriculture,
Conservation, and Trade Act of 1990 (USDA-NRCS 201 Ob). A soil map unit with an erodibility
index (El) of 8 or greater is HEL. The El for a soil map unit is determined by dividing the
potential erodibility for the soil map unit by the soil loss tolerance (T) (USDA-NRCS 201 Oc) T is
an integer value from 1 through 5 tons/acre/year. T of 1 ton/acre/year is for shallow or otherwise
fragile soils, and 5 tons/acre/year is for deep soils that are least subject to damage by erosion.
The classes of T are 1, 2, 3, 4, and 5. A field is considered HEL if either one-third or more of the
field has an El value of 8 or greater or if the HEL in the field totals 50 acres or more (USDA-
NRCS 201 Oa).
Sheet and Rill Equation
R x K x LS = El
T
Chapter 2. Agriculture 2-27
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
where
T = soil loss tolerance, or the maximum rate of annual soil erosion that will permit crop
productivity to be sustained economically and indefinitely (tons/acre/year)
R = rainfall/runoff factor, quantifying the effect of raindrop impact and the amount and rate of
runoff associated with the rain, based on long term rainfall record
K= soil erodibility factor based on the combined effects of soil properties influencing erosion
rates
LS = slope length factor, a combination of slope gradient and continuous extent
The methodology used in implementing the Farm Bill Conservation Reserve Program has
encouraged the retirement of HELs from cropland and replacing the crop with perennial
vegetation.
When the lands are retired through the federal program, a suite of environmental benefit
indicators are considered:
• Water quality benefits from reduced erosion, runoff, and leaching
• Wildlife habitat benefits resulting from covers on contract acreage
• On-farm benefits from reduced erosion
• Benefits that will likely endure
• Air quality benefits from reduced wind erosion
• Cost
Those indicators can be used to assess environmentally sensitive areas as well as USDA-
identified HELs to determine where they are in the Chesapeake Bay watershed. Nutrients
should not be applied to HELs, even if the lands are in continuous cropland production.
For HELs adjacent to stream channels, employ the recommendations from Chapters 5 and 7
(Riparian and Hydromodification) as the perennial vegetation. For information on federal
programs that can assist landowners through the process of land retirement, see Chapter 5.
Emerging and alternative markets can be used in conjunction with this recommendation to make
this viable for the producer.
2-28 Chapter 2. Agriculture
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
When the retirement of HEL will significantly affect the sustainability of the farm and after all
native vegetation markets are considered, a conservation plan to reduce sheet and rill erosion
to T as well as a nutrient management plan should be implemented.
2.1.5 Commercial Fertilizer Use
Implementation Measure A-5:
When using commercial fertilizer, give credit for manure nutrients. When
commercial fertilizer is used, provide for the proper storage, calibration, and
operation of chemical fertilizer nutrient application equipment.
Commercial fertilizers represent the largest single source of N and P applied to most cropland in
the United States. In the Chesapeake Bay watershed, commercial fertilizers are used when
manure is not readily available or undesirable, and are an important source of inorganic nutrient.
Commercial fertilizers can be a tool used to abate the nutrient imbalance in the Chesapeake
Bay watershed; where soils have a high range of P-sat percentage, but are below 20 percent,
commercial N fertilizer can be applied so that manure can be applied at the P rate.
Major commercial fertilizer N sources include anhydrous ammonia, urea, ammonium nitrate
(NH4NO3), and ammonium sulfate [(NH4)2SO4]. Major commercial P fertilizer sources include
monoammonium phosphate, diammonium phosphate, triple superphosphate, ammonium
phosphate sulfate, and liquids. Descriptions of common commercial fertilizer materials are given
in Table 2-1.
Also, where soils have a high range of P-sat below 20 percent, apply commercial N fertilizer to
apply manure at the P rate.
Commercial fertilizers offer the advantage of allowing exact formulation and delivery of nutrient
quantities specifically tailored to the site, crop, and time of application in concentrated, readily
available forms. The use of any particular material or blend is governed by the characteristics of
the formulation (such as volatilization potential and availability rate), suitability for the particular
crop, crop needs, existing soil test levels, economics, application timing and equipment, and
handling preferences of the producer.
Chapter 2. Agriculture 2-29
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
Table 2-1. Common commercial fertilizer minerals
Common name chemical formula
N materials
Ammonium nitrate NH4NO3
Ammonium sulfate (NH4)2SO4
Ammonium nitrate-urea NH4NO3+(NH2)2CO
Anhydrous ammonia NH3
Aqua ammonia NH4OH
Urea (NH2)2CO
Phosphate materials
Superphosphate Ca(H2PO4)2
Ammoniated superphosphate Ca(NH4H2PO4)2
Monoammonium phosphate NH4H2PO4
Diammonium phosphate (NH4)2HPO4
Urea-ammonium phosphate
(NH2)2CO+(NH4)2HP04
Potassium materials
Muriate of potash KCI
Monopotassium phosphate KH2PO4
Potassium hydroxide KOH
Potassium nitrate KNO3
Potassium sulfate K2SO4
Analysis
(%)
N
34%
21%
32%
82%
20%
46%
0%
5%
13%
18%
28%
0%
0%
0%
13%
0%
P205
0%
0%
0%
0%
0%
0%
20%-46%
40%
52%
46%
28%
0%
50%
0%
0%
0%
K2O
0%
0%
0%
0%
0%
0%
0%
0%
0%
0%
0%
60%
40%
70%
45%
50%
Note: Adapted from Pennsylvania State University (1997) and Cornell Cooperative Extension
(1997)
However, because of the nutrient imbalance from the amount of livestock manure produced in
the Chesapeake Bay watershed, EPA recommends that use of commercial fertilizer be
minimized by applying it only to the extent that manure nutrients are not available to be used.
EPA also recommends that provisions be in place for storing fertilizer, as well as regularly
calibrating and properly operating commercial fertilizer application equipment. That
recommendation encourages considering manure as the first-choice source of nutrients. While
there could be an upfront equipment cost, the benefits previously mentioned that manure can
bring to the soil should be considered. Moreover, such an approach will help reduce the
imbalance of nutrients that exists in significant portions of the Chesapeake Bay watershed that
has resulted from the existing excess supply of manure in the watershed.
2-30
Chapter 2. Agriculture
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
2.2 Animal Agriculture
In the Chesapeake Bay watershed, because of the intensity of animal agriculture and manure
generation, it is imperative to control all nutrient sources in the livestock production area. All
AFOs should provide the capacity to properly store for the minimum critical storage period
(dictated by the size of the storage facility) (1) all manure generated, (2) all contaminated runoff
generated, and (3) for open liquid manure storage structures, the direct precipitation from
events in the geographic area, including chronic rain. Proper storage of dry manure, such as
that produced at poultry operations, means covered storage, e.g., in production buildings or
storage sheds. All AFO personnel should also ensure no runoff of pollutants is occurring from
the production area or discharged through conveyances to local waters, including any
precipitation-related water that comes into contact with the animals, animal by-products, litter, or
feed. Proximity to waterbodies, floodplains, HELs, and other environmentally sensitive areas is
a critical consideration in siting manure storage systems.
Strategies for source control associated with animal agriculture focus on containing and treating
feed, manure, and facility wastewater and preventing their movement to surface waters. Four
general principles can help control sources of nutrients and other pollutants from animal
agriculture: animal feed management, manure storage and transport, treatment or processing of
wastes, and management of grazing livestock. NRCS Practice Standards exist for those four
general principles and are referenced throughout this section.
2.2.1 Animal Feed Management
Important feeding strategies for livestock production focus on adjustment of feed additives,
formulations, phase feeding (matching feed to growth stage), or feeding methods to reduce the
nutrient content, change the form of nutrient excreted in manure, and feed as close to animal
requirements as possible (NRCS Practice Code 592 ). Decreasing the P and N content of
manure through diet modification is a powerful, effective approach to reducing the nutrient
balance and nutrient losses from livestock farms (Knowlton et al. 2004; Maguire et al. 2007;
Swink et al. 2009). Reduction of P and N overfeeding, use of feed additives to enhance dietary
P and N utilization, and development of grains in which a high proportion of the P is available
(high-available P, or HAP, grains) have all been shown to decrease P and N excretion without
impairing animal performance (Maguire et al. 2005). Phytase, a feed additive generally used in
poultry or swine feed, is an enzyme that breaks down the form of phosphorus (phytate) that is
found in grains so that the phosphorus can be digested and used by the animal. The phytase
enzyme is regularly produced and is present naturally in ruminants (e.g., dairy and beef cattle).
The ratio of N to P in manure applied to the land is a critical issue. Manures used as fertilizers
on fields commonly contain N:P ratios of approximately 3:1, whereas most major crops require
Chapter 2. Agriculture 2-31
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
N:P ratios of approximately 8:1. Application of manure to meet N requirements consequently
tends to apply excess P. Two major factors contributing to the low N:P ratio in manure are the
loss of N through ammonia volatilization and the presence of excess P in the diets of farm
animals. In addition to reducing the P content of manure through feed management, the
combination of reducing N volatilization losses and immobilization of P through manure or litter
amendment can significantly increase the final N:P ratio of land applied manure (Lefcourt and
Meisinger2001).
Finally, some feed additives that pass through the animal and reside in the manure can be
problematic in the environment. For example, most of the arsenic used as an antibiotic in
commercial broiler production remains in the litter. As a result, higher levels of arsenic tend to
be found in soils that receive poultry litter compared to areas where litter is not applied.
Reducing or eliminating arsenic in poultry feed can reduce this problem.
Implementation Measure A-6:
Formulate animal feeds to reduce nutrient concentration in manure, improve the
manure N:P ratio in relation to crop needs, or eliminate toxic substances such as
arsenic in manure used as fertilizer. Align the N:P ratio of the manure to be equal to
(or greater than) the N:P ratio of the crop need.
Practice Effectiveness
Several studies have shown that reducing the nutrients in feed has a significant effect on the
manure nutrient content.
Arriaga et al. (2009) estimated that dietary manipulation in Spain could decrease dairy herd N
excretion by 11 percent per hectare, whereas P would be decreased by 17 percent. On two
New York dairy farms, Cerosaletti et al. (2004) reported that fecal P concentrations decreased
33 percent following dietary adjustments; milk production was not adversely affected. In a
modeling study of the same New York farms, precision feed management reduced the P
imbalance on each farm and reduced the soluble P lost to the environment by 18 percent
(Ghebremichael et al. 2007). Ebeling et al. (2002) applied dairy manure from two dietary P levels
to corn land in Wisconsin and reported that at equivalent manure rates, dissolved P concentration
in runoff from the high P diet manure was 10 times higher (2.84 versus 0.30 mg/L) than the low P
diet manure, and four times higher (1.18 versus 0.30 mg/L) when applied at equivalent P rates.
In a review, Graham et al. (2003) reported that including xylanase or phytase in poultry feeds can
reduce manure volume by up to 14 percent and N and P outputs by up to 13 percent and
70 percent, respectively. A review by Powers and Angel (2008) reported that for each one percent
2-32 Chapter 2. Agriculture
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
reduction in dietary crude protein, estimated NH3 losses are decreased by 10 percent, creating the
potential for a 20-40 percent reduction in NH3 emissions from poultry houses. For P, under
commercial conditions, broiler litter P was decreased by 30 percent when diet P was decreased
by 10 percent. In North Carolina, Leytem et al. (2008) reported that inclusion of phytase in poultry
diets at the expense of inorganic P or reductions in dietary available P decreased litter total
phosphorus (TP) by 28 to 43 percent. Litter water-soluble P decreased by up to 73 percent with
an increasing dietary Ca/available P ratio, irrespective of phytase addition. Nahm (2009) found
that phytase addition to simple gastric animal diets in South Korea can decrease the litter water-
soluble P concentration by 30-35 percent. In Arkansas, Smith et al. (2004) showed that phytase
and HAP corn diets reduced litter-dissolved P content in broiler litter by 10 and 35 percent,
respectively, compared with the normal diet (789 mg P/kg). P concentrations in runoff water were
highest from plots receiving poultry litter from the normal diet, whereas plots receiving poultry litter
from phytase and HAP corn diets had reduced P concentrations.
In Canada, Emiola et al. (2009) showed that complete removal of inorganic P from growing pig
diets coupled with phytase supplementation improves digestibility and retention of P and N, thus
reducing manure P excretion without any negative effect on pig performance. In another
Canadian study, Grandhi (2001) reported that replacing inorganic P with phytase and lowering
the dietary protein level while supplementing amino acids in swine diets can decrease the
excretion of P up to 44 percent and N up to 28 percent in manure with no adverse effect on
performance of pigs. In a Danish study, replacing inorganic phosphates with phytase in pig feed
reduced the concentration of P in slurry by 35 percent (Sommer et al. 2008). In Europe, Aarnink
and Verstegen (2007) found that a combination of lowering crude protein intake and increasing
fermentable carbohydrates, and other modifications to feeding strategies could reduce ammonia
emission from growing-finishing pigs by 70 percent.
Despite ample research evidence that phytase addition, use of HAP feeds, and other
approaches can significantly reduce N and P content in manure, marketing and adoption of
such feeds has been slow. Recent survey data in Delaware suggest that poultry producers with
high soil P levels are willing to adopt HAP corn, despite increased costs and yield loss (Bernard
and Pesek 2007). It is possible that the lack of economic return for sales of HAP seed has
inhibited production and marketing of modified seed by suppliers. There is an apparent need for
additional work in this area to determine how to effectively get this promising technology into
wider production and use.
Dao (1999) reported that treatment of cattle manure with alum and other amendments can
increase the effective N:P ratio in manure, bringing it into a range suitable for using manure as a
balanced source of nutrients for crop production. Alum addition to stockpiled and composted
cattle manure reduced water-extractable P (WEP) in the manure by 85-93 percent. Worley and
Das (2000) reported that separation of solids from flushed swine manure and subsequent
Chapter 2. Agriculture 2-33
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
amendment with alum removed 75 percent of P and only small amounts of N from the manure.
As a result, the N:P ratio of the effluent entering the lagoon improved from 3.6 without
separation to 8 with separation and to 16.7 with separation and alum amendment.
Table 2-2. Summary of reported practice effects resulting from changes in animal feeding
strategies
Location
Spain
New York
New York
Wisconsin
Many
Many
North
Carolina
S Korea
Arkansas
Canada
Canada
Denmark
Europe
Study
type
Farms
Farm
Model
Field
Review
Review
Animal
trials
Review
Farm/
Plot
Animal
trials
Animal
trials
Farm
Review
Practice
Dairy feed
formulation
Dairy dietary
management
Dairy precision
feeding
Dairy dietary
management
Phytase in
poultry feed
Poultry feed
formulation
Phytase in
poultry feed
Phytase in
poultry feed
Phytase and
high available
P corn in
poultry feed
Swine diet
Swine diet
Phytase in
swine diet
Swine feeding
strategies01
Practice effects
11% reduction in N excretion;
17% reduction in P excretion
33% reduction in manure P concentration
18% reduction in soluble P lost from farm
75% reduction in dissolved P in runoff from
land applied manure3
14% reduction in manure volume; 13%
reduction in litter N, 70% reduction in litter P
10% reduction in NH3 losses per 1%
decrease in dietary crude protein; 30%
reduction in litter P with 10% reduction in
dietary P
28%-43% decrease in litter TP;
Up to 73% reduction in litter water-soluble Pb
30%-35% reduction in litter water-soluble P
10% reduction in litter dissolved Pwith
phytase; 35% reduction with high available P
cornc
Removal of inorganic P from diet plus
phytase supplementation improved
digestibility and retention of P and N,
reduced manure P excretion without
negative effects on growth
44% reduction in P excretion, 28% reduction
in N excretion from replacing inorganic P
with phytase and lowering dietary protein
35% reduction in P in slurry
70% reduction in ammonia emissions from
growing-finishing operations
Source
Arriaga et al. 2009
Cerosaletti et al.
2004
Ghebremichael et
al. 2007
Ebeling et al. 2002
Graham et al. 2003
Powers and Angel
2008
Leytem et al. 2008
Nahm2009
Smith et al. 2004
Emiola et al. 2009
Grandhi 2001
Sommeretal. 2008
Aarninkand
Verstegen 2007
Notes:
a. High-P diet manure and low-P diet manure applied at equivalent P rates
b. With increasing Ca/available P in feed, irrespective of phytase
c. Study also reported that P concentrations in plot runoff were reduced where litter from modified
d. Feeding changes included lowering crude protein intake, increasing fermentable carbohydrates
acidifying salts
diets was applied
, and addition of
2-34
Chapter 2. Agriculture
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
Practice Costs
In an experiment in India, Khose et al. (2003) reported that the cost of broiler production per kg
live weight was lowest in the group fed the diet with a 50 percent reduction in feed dicalcium
phosphate supplemented with phytase. Osei et al. (2008) used an integrated economic and
environmental modeling system to evaluate effects of N- and P-based manure application rates
in Texas. Results of the study indicate that edge-of-field TP losses can be reduced by about
0.8 kg/ha/year or 14 percent when manure applications are calibrated to supply all the
recommended crop P requirements from manure TP sources only versus manure applications
at the recommended crop N agronomic rate. Corresponding economic effects are projected to
average a 4,852 (2010 dollars) annual cost increase per farm.
2.2.2 Manure Storage and Transport
Implementation Measure A-7:
Safely and strategically apply (with properly calibrated equipment), store, and
transport manure.
• Liquid manure storage systems including tanks, ponds, and lagoons
(e.g., NRCS Practice Code 313 Waste Storage Facility) should be designed
and operated to safely store the entire quantity and contents of animal
manure and wastewater generated, contaminated runoff from the
facility, and the direct precipitation from events in the geographic area,
including chronic rain.
• Dry manure (i.e., stackable, greater than or equal to 20 percent dry
matter), such as that produced in poultry and certain cattle operations,
should be stored in production buildings, storage facilities, or otherwise
covered to prevent precipitation from coming into direct contact with the
manure and to prevent the occurrence of contaminated runoff. When
necessary, temporary field storage of dry manure (e.g., poultry litter)
may be possible under protective guidelines (e.g., NRCS Practice Code
633 Waste Utilization).
• For manure and litter storage, the AFO should maintain sufficient
storage capacity for minimum critical storage period consistent with
planned utilization rates or utilization practices and schedule.
Chapter 2. Agriculture 2-35
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
The manure and other wastes generated by livestock production should be contained and
management should prevent runoff losses from the facility. Key measures and some component
practices (including some as USDA-NRCS National Practice Codes) include the following:
• Ensure that the farm has sufficient storage for all manure.
- Waste storage facility (NRCS Practice Code 313): A waste impoundment made by
constructing an embankment, excavating a pit or dugout, or by fabricating a
structure.
- Waste treatment lagoon (NRCS Practice Code 359): An impoundment made by
excavation or earth fill for biological treatment of animal or other agricultural wastes.
• Ensure that manure and litter are stockpiled safely.
- Waste Utilization (NRCS Practice Code 6332): Using agricultural wastes, such as
manure and wastewater, or other organic residues (including temporary field
storage).
• Minimize the need for temporary storage by scheduling clean-outs as close to utilization
as possible.
• Locate storage on level ground not subject to flooding and away from surface waters and
wells.
• Stack manure on an impermeable pad or in areas with adequate separation from the
groundwater table.
• Rotate temporary storage areas to avoid buildup of salts and nutrients in a single
location.
• Cover stockpiles when practical. Although data on the benefits of covering poultry litter is
mixed (Poultry Litter Experts Science Forum 2008), there is evidence that dry broiler
litter should be covered to protect litter quality and to prevent extensive nutrient runoff
(Mitchell et al. 2007). Most Extension recommendations call for covering field stockpiles
of poultry litter and other solid manure (e.g., Carter and Poore 1998, Arkansas
Cooperative Extension Service 2006, Ogejo 2009).
• Minimize stockpile footprint and provide grass filter strip to protect downslope areas.
- Set total (whole-house) clean-out schedules that ensure no poultry litter stockpiling
during times of the year with the greatest environmental losses (e.g., winter).
2 NRCS Practice Code 633 is being revised at the national level. If the practice cannot be isolated as a unique
technology different from the technology delivered by NRCS Code 590, it may be abandoned or redefined. Interested
parties should be advised that the 590 is under revision and that 633 practice will be redefined or abandoned.
2-36 Chapter 2. Agriculture
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
- Divert clean water away from waste storage areas.
- Diversion (NRCS Practice Code 362): A channel constructed across the slope with
a supporting ridge on the lower side.
- Roof runoff management (NRCS Practice Code 558): A facility for controlling and
disposing of runoff water from roofs.
• Ensure that any recipient of manure generated has planned effectively to meet, at a
minimum, the same performance goals as those of the sourced manure.
- Areas receiving manure should be managed in accordance with meeting the goals
for erosion and sediment control, irrigation, and grazing management applicable,
including practices such as crop and grazing management practices to minimize
movement of applied nutrient and organic materials, and buffers or other practices to
trap, store, and process materials that might move during precipitation events.
- Waste utilization (NRCS Practice Code 633): Using agricultural wastes or other
wastes on land in an environmentally acceptable manner while maintaining or
improving soil and plant resources.
Measures for manure storage protect the wastes from precipitation and runoff and provide
opportunities for further treatment (see Section 2.2.4) or for subsequent manure management
according to a nutrient management plan (see Section 2.1.1). Thus, little recent literature exists
quantifying the effectiveness of waste storage alone. General pollutant reductions associated
with containment structures were reported (TP 60 percent, TN 65 percent, sediment 70 percent,
and fecal coliform 90 percent) in National Management Measures to Control Nonpoint Pollution
from Agriculture (USEPA 2003) based on information published by Pennsylvania State
University (PSU 1992). Mitchell etal. (2007) reported high nutrient losses in runoff from
uncovered poultry litter. Habersack (2002) studied runoff from uncovered and covered poultry
manure stockpiles and concluded that even protecting litter piles with the common 95 percent
plastic coverage technique was unsuccessful in reducing environmental pollution. It was
recommended that poultry litter be stored in a litter shed that prevents all contact from
precipitation and runoff. Reductions of fecal coliform bacteria numbers of two to three orders of
magnitude have been reported with manure storage for 2 to 6 months (Patni et al. 1985; Moore
etal. 1988).
Practice Costs
Concrete pits for storing wet animal waste can cost from $42.50/yd3 for pits larger than 1,000
yd3 to $159/yd3 for pits smaller than 370 yd3, with typical total costs ranging from $42,800 for
smaller pits to over $200,000 for larger pits (USDA-NRCS 2010). The cost of earthen ponds
ranges from $9.92/yd3 for ponds larger than 1,000 yd3 to $13.65/yd3 for smaller ponds. A typical
Chapter 2. Agriculture 2-37
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
small, earthen pond costs about $12,500, while a larger pond could cost just under $17,000.
Earthen floor storage for dry waste costs from $41.50 to $55.90 per cubic yard, with typical
small (less than or equal to 1,000 yd3) structures costing just over $37,000 and larger structures
costing nearly $50,000. Storage of dry wastes costs more with concrete floors ($70.90 to $106
per cubic yard); structures with a capacity of less than or equal to 500 yd3 typically cost around
$50,000 whereas larger structures cost nearly $70,000. Loose housing for dry waste storage
costs about $207 per cubic yard, and typical structures holding 1,150 cubic yards cost about
$240,000. Waste field storage consisting of fabric and gravel with a tarp costs $1.62/ft2 while a
concrete slab and tarp goes for $3.67/ft2 in Virginia, with typical total costs of $11,310 and
$14,665, respectively (USDA-NRCS 2010).
Waste treatment lagoons with earthen bottoms cost about $13 per cubic yard, and lagoons
typically cost about $21,440 (USDA-NRCS 2010). Pond sealing or lining with flexible membrane
($1.38/ft2), soil dispersant ($1.52/ft2), or bentonite clay ($1.52/ft2) are improvement options in
Virginia for which total costs are typically in the range of $6,700 to $7,500. Sealing with
compacted clay costs about $6.91 or $16.63 per cubic yard of earth moved for on-site and off-
site clay sources, respectively. Typical total costs for compacted clay liners are about $2,300 for
on-site clay and $5,500 for off-site clay.
Earthen diversions cost about $2.70 per linear foot. Roof runoff structure costs range from
$1.84/gallon for underground cisterns with hookup, to $4.54/ft for downspouts and drain lines, to
$6.00/ft for 6-inch gutters. Dry poultry spreading generally costs about $33.90/ac, whereas
spreading of liquid dairy waste costs about $12.50/ac. Waste utilization via lagoons and
irrigation systems cost about $377/ac, with typical systems running about $66,000.
2.2.3 Livestock Exclusion from Streams
Implementation Measure A-8:
Exclude livestock from streams and streambanks to reduce nutrient inputs,
streambank erosion, and sediment inputs and to improve animal health.
Grazing livestock should be excluded from streams and riparian areas to reduce direct nutrient
and pathogen inputs, prevent streambank damage and resulting sediment inputs, and improve
animal health (NRCS Practice Code 472). Fencing is the most reliable way to protect streams
and riparian areas from the effects of livestock, and can be woven wire or electric (NRCS
Practice Code 382). Cost-share programs might require permanent fencing, rather than
temporary or movable fence. Management intensive or rotational grazing could, however,
involve using movable fences to create temporary paddocks to direct livestock away from a
water course. If complete fencing is not possible, the most sensitive streambank areas should
2-38 Chapter 2. Agriculture
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
be fenced, while providing an alternate watering source (NRCS Practice Code 614) for access
to drinking water for grazing animals. Some trials have documented success in keeping
livestock out of streams without continuous fencing by providing drinking water and/or shade
away from the stream to encourage livestock to congregate away from riparian areas.
Practice Effectiveness
Livestock exclusion fencing
Line et al. (2000) documented 33, 78, 76, and 82 percent reductions in weekly nitrate + nitrite,
total Kjeldahl nitrogen (TKN), TP, and sediment loads, respectively, resulting from fencing dairy
cows from a 10- to 16-m wide riparian corridor along a small North Carolina stream. In the same
system, Line (2003) showed that fecal coliform and enterococci levels decreased 65.9 percent
and 57.0 percent, respectively, after livestock exclusion.
In Vermont streams draining dairy pastures, Meals (2002) reported 20-50 percent reductions in
nutrient and suspended solids loads and 40-60 percent reductions in fecal bacteria counts
following livestock exclusion and riparian restoration with bioengineering techniques.
James et al. (2007) estimated 32 percent reduction of in-stream deposition of fecal P by grazing
dairy cattle in New York following livestock exclusion under the CREP.
In central Pennsylvania, Carline and Walsh (2007) reported that following riparian treatments,
consisting of fencing, 3- to 4-m buffer strips, stream bank stabilization, and rock-lined stream
crossings, stream bank vegetation increased from 50 percent or less to 100 percent in formerly
grazed riparian buffers, suspended sediments during base flow and storm flow decreased
47-87 percent, and macroinvertebrate densities increased in two treated streams.
However, Agouridis et al. (2005) reported that incorporation of an alternate water source or
fenced riparian area along a central Kentucky stream did not significantly alter stream cross-
sectional area where the measures were applied. The authors suggested that riparian recovery
within the exclosures from pretreatment grazing practices might require decades, or greater
intervention (i.e., stream restoration), before a substantial reduction in streambank erosion is
noted.
Chapter 2. Agriculture 2-39
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
Table 2-3. Summary of reported practice effects resulting from livestock exclusion
Location
North
Carolina
North
Carolina
Vermont
New
York
Pennsyl-
vania
Georgia
North
Carolina
Study type
Small
watershed
Small
watershed
Small
watersheds
Stream
Small
watersheds
Stream
Stream
Practice
Fencing dairy
cattle
Fencing dairy
cattle
Fencing dairy
cattle; riparian
restoration
Fencing dairy
cattle3
Fencing, buffer
strips, stream
bank stabilization,
rock-lined stream
crossings
Off-stream water
supply
Off-stream water
supply
Practice effects
Load reductions: 33% NO2+NO3-N,
78% TKN, 76% TP, and 82%
sediment
Reductions: 66% fecal coliform, 57%
enterococci
Load reductions: 20-50% TP, TKN,
TSS
Reductions: 40-60% fecal coliform,
fecal strep., and E. coli
32% reduction in deposition of fecal P
in stream
Streambank vegetation increase from
<50% to 100%; 47-87% reduction in
SS concentrations; increase in
macroinvertebrate densities
63% decrease time cattle spent in
riparian zones
No significant changes in physical
water quality parameters or bacteria
counts
Source
Line et al. 2000
Line 2003
Meals 2002
James et al. 2007
Carline and Walsh
2007
Franklin et al.
2009
Line 2003
Note:
a. Livestock exclusion under Conservation Reserve Enhancement Program (CREP)
Alternative water supply
In Georgia, Franklin et al. (2009) found that when the temperature and humidity index ranged
between 62 and 72, providing cattle with water troughs outside of riparian zones tended to
decrease time cattle spent in riparian zones by 63 percent. The study suggests that water
troughs placed away from unfenced streams can improve water quality by reducing the amount
of time cattle spend in riparian zones.
However, Line (2003) reported that levels of most measured physical parameters and bacteria
were not significantly different following the installation of alternate water supply in a North
Carolina pasture.
Practice Costs
Fence costs range from $0.49/ft for 1-strand, stainless steel electric poly wire used as
temporary fencing, to $8.77/ft for 4-foot chain-link fence with one strand of barbed wire (USDA-
NRCS 2010). Most fencing falls within the range of about $2/ft to $3/ft, with typical total costs of
about $3,000 to $4,000. Watering facilities cost about $812 each for converted heavy truck tires
2-40
Chapter 2. Agriculture
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
to as much as $1,700 for 4-hole, freeze-proof troughs including gravel and a concrete pad.
Portable shade structures for livestock cost $4.85/ft2 for a typical total cost of $1,940.Graded
stream crossings made of gravel and fabric cost under $2.50/ft2, while stream crossings with
concrete access or culverts cost about $4.10/ft2 and $4.90/ft2, respectively (USDA-NRCS 2010).
Typical total costs for graded stream crossings range from $1,700 to $2,900 for gravel and
fabric, to $4,300 with concrete access, to just over $5,100 for culverts.
2.2.4 Wastewater and Animal Wastes
Implementation Measure A-9:
Process/treat through physical, chemical, and biological processes facility wastewater
and animal wastes to reduce as much as practicable the volume of manure and loss
of nutrients.
Manure and wastewater stored on farms has a significant pollution potential even after wastes
are collected and stored appropriately. Researchers have recommended a variety of practices
to manage the effects of animal wastes, focusing on treating waste to change its physical,
chemical, or biological properties; remove potential pollutants; or improve handling
characteristics (Bicudo and Goyal 2003; Ritter et al. 2003; Martinez et al. 2009).
Such practices include the following:
• Waste treatment and processing—treating manure or farm wastewater to separate
liquids and solids, immobilize pollutants, or remove nutrients from the waste stream
• Digestion—processing animal wastes to capture biogas for use as fuel, reducing bulk of
remaining residuals for further management. The digestion process removes only
carbon, hydrogen, and water from the animal waste; the residuals from digestion contain
all the N, P, and trace minerals and about half of the carbon of the original manure.
• Composting—composting of animal wastes, possibly combined with other green
wastes, to reduce bulk, stabilize nutrient forms, and facilitate export and land application
of animal wastes. High temperatures during composting kill manure microorganisms,
largely eliminating the risk of contaminating crops with pathogens where composted
manure is land-applied. Composting reduces the mass and volume of manure
significantly, while P content remains essentially unchanged. Substantial N losses can
occur, however, through volatilization of ammonia N created by decomposition of
organic N and by conversion of organic N to NO3 followed by leaching.
• Constructed Wetland treatment—to remove nutrients by plant uptake and promotion of
denitrification
Chapter 2. Agriculture 2-41
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
• Other biological treatments—treatment systems using microorganisms, algae, or other
plants to break down wastes and absorb nutrients
• Air quality management—practices to reduce or capture airborne pollutants like
ammonia or fine particulates from animal housing
Practice Effectiveness
Waste treatment and processing—manure and wastewater amendment
Amending poultry litter with alum [AI3(SO4)2-14H2O] is a method of economically reducing
ammonia volatilization in the poultry house and soluble P in runoff waters (e.g., Amendments for
Treatment of Agricultural Waste, NRCS Practice Code 591). In South Korea, Do et al. (2005)
reported that application of aluminum chloride (AICI3-6H2O) to litter lowered atmospheric
ammonia concentrations at 42 days by 97.2 percent, whereas ferrous sulfate (FeSO4-7H2O)
lowered it by 91 percent. Ammonia concentrations were reduced by 86, 79, 76, and 69 percent
by alum, alum + CaCO3, aluminum chloride + CaCO3, and potassium permanganate (KMnO4),
respectively, when compared with a control at 42 days. The addition of 6.25 percent zeolite or
2.5 percent alum to dairy slurry in Maryland reduced ammonia emissions by nearly 50 and 60
percent, respectively. Alum treatment retained ammonia by reducing the slurry pH to 5 or less.
In contrast, zeolite, (a cation exchange medium) adsorbed ammonium and reduced dissolved
ammonia gas (Lefcourt and Meisinger 2001).
In Arkansas, Moore et al. (1999 and 2000) reported that reductions in litter pH in alum-treated
broiler litter reduced NH3 volatilization by 97 percent, which led to reductions in atmospheric
NH3 in the alum-treated houses. Broilers grown on alum-treated litter were significantly heavier
than controls (1.73 kg versus 1.66 kg). Soluble reactive P (SRP) concentrations in runoff from
pastures fertilized with alum-treated litter were 75 percent lower than those from normal litter.
Also in Arkansas, Smith et al. (2001) found that alum and aluminum chloride amendment to
swine manure reduced SRP concentrations in runoff by 84 percent that were not statistically
different from SRP concentrations in runoff from unfertilized control plots. Smith et al. (2004)
reported that the addition of alum to various poultry litters reduced P runoff by 52 to 69 percent
from pastures where the litter was applied; the greatest reduction occurred when alum was used
in conjunction with dietary modification with HAP corn and phytase.
In Pennsylvania, Dou et al. (2003) reported reductions of soluble P in dairy, swine, and broiler
manures of 80 to 99 percent at treatment rates of 100 to 250 g alum/kg manure dry matter.
Fluidized bed combustion fly ash reduced readily soluble P by 50 to 60 percent at a rate of
400 g/kg for all three manures. Flue gas desulfurization by-product reduced soluble P by nearly
80 percent when added to swine manure and broiler litter at 150 and 250 g/kg.
2-42 Chapter 2. Agriculture
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
Table 2-4. Summary of reported practice effects resulting from waste amendment
Location
Korea
Maryland
Arkansas
Arkansas
Arkansas
Pennsyl-
vania
Unknown
Unknown
Ohio
Vermont
Idaho
Taiwan
Study type
Poultry
house
Dairy farm
Poultry
houses
Field
Plots
Laboratory
Laboratory
Laboratory
Laboratory
Laboratory
Field
Laboratory
Practice
Poultry litter
amendments
Dairy slurry
amendments
Alum
amendment
Alum and
aluminum
chloride treated
poultry litter
Alum and
aluminum
chloride treated
swine manure
Dairy, swine,
broiler manure
amendments
Dairy
wastewater
amendment
Dairy manure
amendment
Dairy manure
amendment
Dairy manure
amendment
Cattle, swine
manure
amendment
Swine
wastewater
amendment
Practice effects
Atmospheric ammonia concentration
reductions:
97% (Aluminum chloride), 91% (Ferrous
sulfate), 86% (alum), 79% (alum+CaCO3),
76% (aluminum chloride+CaCO3),
69% (KMn04)
50% ammonia emissions reduction (zeolite),
60% ammonia emissions reduction (alum)
97% ammonia volatilization; 75% reduction
in soluble P in runoff from pastures receiving
treated litter
52%-69% reduction in P concentration in
runoff from pastures where treated litter
applied3
84% reduction in soluble P concentration in
runoff from plots receiving treated manure; P
concentration not significantly different from
un-manured control plots
Manure soluble P reductions: 80-99%
(alum), 50%-60% (fly ash), 80% (flue gas
desulfurization byproduct
93%-99% reduction in ortho-P with alum
treatment; ortho-P reduced to <1 mg P/L by
alum and PAM combined
Liquid from separated manure amended with
alum and polymer had 82% less TP, 36%
less TS, and 71% lower COD than untreated
manure
Amending dairy manure with WTR reduced
CaCI2-extractable P >75%
Amending dairy manure with alum-based
WTR reduced manure soluble P up to 79%,
TP up to 50%
Amending manure with PAM, alum, and CaO
treatments reduced fecal bacteria 90->99%
in runoff from application sites compared to
untreated manure control
Amending swine wastewater with alum, ferric
chloride, calcium hydroxide, and
polyaluminum chloride reduced COD by 54%
Source
Do et al. 2005
Lefcourt and
Meisinger
2001
Moore et al.
1999 and 2000
Smith et al.
2004
Smith et al.
2001
Dou et al.
2003
Jones and
Brown 2000
Oh et al. 2005
Dayton and
Basta 2005
Meals et al.
2007
Entry and
Sojka 2000
Cheng 2001
Note:
a. Greatest P reductions when alum used in conjunction with dietary modification
Chapter 2. Agriculture
2-43
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
In laboratory studies, alum reduced ortho-P in dairy wastewater 93-99 percent at rates less
than three g alum/L. Ortho-P was reduced to one mg P/L or less by a combination of alum and
polyacrylamide (PAM) treatment (Jones and Brown 2000).
Oh et al. (2005) reported that alum and polymer addition improved the efficacy of mechanical
separation of dairy manure. When compared to the control, waste amended with alum and
polymer had 82 percent less TP in the press liquor, which indicates that P was partitioned into
the press cake. The combined alum/polymer treatment also resulted in a 36 percent reduction in
total solids (TS) and a 71 percent reduction in chemical oxygen demand (COD) in the press
liquor when compared to the control.
Codling et al. (2000) recommended substituting Al-rich drinking WTR for alum for reducing
water-soluble P in poultry litter. In Ohio, Dayton and Basta (2005) reported that blending WTR to
manure at 250 g/kg reduced CaCI2-extractable P by greater than 75 percent. In a Vermont
study, Meals et al. (2007) found that additions of alum-based WTR to liquid dairy manure could
reduce manure soluble P concentrations up to 79 percent and TP concentrations by up to
50 percent.
In Idaho, Entry and Sojka (2000) reported that treatment of cattle and swine manure with
combinations of PAM, aluminum sulfate (AI(SO4)3), and calcium oxide (CaO) treatments
reduced fecal bacteria counts by 10- to 1,000-fold in water flowing downstream of treated
manure application sites, compared to the untreated manure control.
In Taiwan, Cheng (2001) was able to reduce COD levels in swine wastewater by 54 percent to
190 mg/L using coagulants such as aluminum chloride, ferric chloride, calcium hydroxide, and
polyaluminum chloride.
Waste treatment and processing—waste separation
Note that waste separation does not treat wastes in the sense of removing or inactivating
pollutants; rather, the process of separation produces a separate liquid and solid waste stream
that could facilitate handling, transport, and further use of waste components.
An inclined stationary screen separator removed 61 percent of the TS, 63 percent of the volatile
solids, 49 percent of the TKN, 52 percent of the organic-N, and 53 percent of the TP from South
Carolina dairy manure in a flush system; the complete manure treatment system consisting of
the screen separator, separator, a two-chambered settling basin, and a lagoon removed
93 percent of the TS, 96 percent of the VS, 74 percent of the TKN, 91 percent of the organic-N,
and 86 percent of the TP (Chastain et al. 2001).
2-44 Chapter 2. Agriculture
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
In Wisconsin, Converse and Karthikeyan (2004) reported that long-term settling of flushed dairy
manure will remove 75 to 80 percent of TP from raw flushed manure or separator effluent and
concentrate it in the bottom 25 percent of the volume. Cantrell et al. (2008) reported that
geotextile filtration of liquid dairy manure in South Carolina reduced volume to less than one
percent of total influent volume, concentrated the solids and nutrients in the dewatered material
16 to 21 times greater than the influent, and retained 38 percent of TS, 26 percent of TKN, and
45 percent of TP. In South Carolina, Garcia et al. (2009) used the natural flocculant chitosan to
improve the performance of screen separation efficiencies for flushed dairy manure to greater
than 95 percent for total suspended sediment (TSS), greater than 73 percent for TKN, and
greater than 54 percent for TP.
Table 2-5. Summary of reported practice effects resulting from waste separation
State
South
Carolina
South
Carolina
Wisconsin
South
Carolina
South
Carolina
North
Carolina
North
Carolina
Study type
Farm
Farm
Laboratory
Farm
Farm
Farm
Farm
Practice
Inclined
stationary
screen
separator
Separator +
settling basin
+ lagoon
Long-term
settling
Geotextile
separation
Flocculation +
separation
PAM +
screening
Flocculation +
filtration
Practice effects
For flush-system dairy manure, separator
removed 61% of TS, 63% of the volatile
solids, 49% of the TKN, 52% of the organic-
N, and 53% of the TP
For flush-system dairy manure, full system
removed 93% of TS, 96% of the volatile
solids, 74% of the TKN, 91% of the organic-
N, and 86% of the TP
75%-80% of TP removed from raw flushed
dairy manure, concentrated in 25% of
original volume
For liquid dairy manure, reduced volume to
< 1% of influent volume and retained 38% of
TS, 26% of TN, and 45% of TP
Use of natural flocculant chitosan improved
performance of screen separation
efficiencies for flushed dairy manure to
>95% for TSS, > 73% for TKN, and > 54%
forTP
For swine waste, addition of PAM before
screening increased separation efficiencies
to 95% TSS and VSS, 92% organic P, 85%
organic N, 69% COD, and 59% BOD5;
System removed 97% of TSS and VSS, 85%
of BOD, 83% of COD, 61% TKN, and 72% of
TP from flushed swine manure
Source
Chastain et
al. 2001
Chastain et
al. 2001
Converse
and
Karthikeyan
2004
Cantrell et al.
2008
Garcia et al.
2009
Vanotti et al.
2002
Vanotti et al.
2005
Chapter 2. Agriculture
2-45
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
Although screening alone was not effective for separating swine waste in a North Carolina
study, Vanotti et al. (2002) found that adding RAM before screening increased separation
efficiencies to 95 percent TSS and volatile suspended solids (VSS), 92 percent organic P,
85 percent organic N, 69 percent COD, and 59 percent BOD5; the N:P ratio was improved from
4.79 to 12.11, resulting in a more balanced effluent for fertilizing crops. In a subsequent study,
Vanotti et al. (2005) reported that a combined flocculation and filtration treatment system
removed 97 percent of TSS and VSS, 85 percent of BOD, 83 percent of COD, 61 percent TKN,
and 72 percent of TP from flushed swine manure.
Waste treatment and processing—lagoon treatment
Waste treatment processes typically leave a residual material after producing a cleaner effluent;
thus, the reductions cited in the literature generally refer to the treated effluent compared to the
original waste. In all cases, the residual should be managed properly to prevent pollution
impacts.
Aerobic lagoon treatment of swine waste in Nova Scotia accomplished removals of 59-71
percent TSS, 59-73 percent VSS, 42-60 percent TKN, and 42-51 percent NH4-N (Trias et al.
2004). In France, combined aerobic/anoxic treatment of swine manure wastewater achieved
86 percent reduction in TSS, 90 percent reduction in TN and COD (Prado et al. 2009);
50 percent of soluble P was biologically removed by an intermittent aerobic/anoxic sequence.
In Korea, Ra et al. (1998) reported that a two-stage sequencing batch reactor system achieved
removal efficiencies of 98 percent total organic carbon (TOC), 100 percent NH4-N, 98 percent
TKN, 97 percent ortho-P, 98 percent TP, 97 percent suspended solids (SS) and 97 percent
VSS.
Vanotti and Szogi (2008) tested a new swine waste treatment system combining liquid-solids
separation with biological N and P removal in North Carolina and reported removal of 73-98
percent TSS, 40-76 percent of TS, 77-100 percent of BOD5, 85-98 percent of TKN and NH4-N,
38-95 percent of TP, and 37-99 percent of Zn and Cu. A second-generation version of the
system removed 98 percent TSS, 97 percent NH4-N, 95 percent TP, 99 percent Zn and Cu,
99.9 percent odors, and 99.99 percent pathogens (Vanotti et al. 2009).
2-46 Chapter 2. Agriculture
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
Table 2-6. Summary of reported practice effects resulting from lagoon treatment
Location
Nova
Scotia
France
Korea
North
Carolina
North
Carolina
Study
type
Farm
Farm
Farm
Farm
Farm
Practice
Aerobic lagoon
Aerobic/anoxic
lagoons
Two- stage
sequencing batch
reactor
Solids separation +
biological N and P
removal
Solids separation +
biological N and P
removal (2nd
generation)
Practice effects
For swine waste, removals of 59%-71% TSS,
59%-73% VSS, 42%-60% TKN, and 42%-
51% NH4-N
For swine manure wastewater, achieved
86% TSS reduction, 90% TN and COD
reduction; 50% of soluble P was biologically
removed by an intermittent aerobic/anoxic
sequence.
Removal efficiencies of 98% TOC, 100% NH4-
N, 98% TKN, 97% ortho-P, 98% TP, 97%
suspended solids, and 97% volatile
suspended solids from swine waste
For swine waste treatment, removal of
73-98% TSS, 40%-76% of TS, 77%-100% of
BOD5, 85-98% of TKN and NH4-N, 38%-95%
of TP, and 37%-99% of Zn and Cu.
For swine waste treatment, removal of 98%
TSS, 97% NH4-N, 95% TP, 99% Zn and Cu,
99.9% odors, and 99.99% pathogens
Source
Trias et al.
2004
Prado et al.
2009
Ra et al.
1998
Vanotti and
Szogi 2008
Vanotti and
Szogi 2009
Waste treatment and processing—other treatment
Masse et al. (2007) reviewed the most recent literature on membrane filtration for manure
concentration and treatment and found studies of ultrafiltration of manure that reported up to
100 percent removal of coliform and SS, 87 percent P reduction, but no effect on soluble COD
from ultrafiltration (0.01 u,m) and lower efficiency from microfiltration (0.2 urn), e.g., 75 percent
SS removal.
In Ireland, Healy et al. (2004) tested recirculating sand filters for treatment of dairy wastewater
and reported TN reduction of 27 to 41 percent; TN reduction increased to 83 percent when sand
filter effluent was recirculated through an anoxic zone. A subsequent study (Healy et al. 2007)
reported consistent COD and TSS removals of greater than 99 percent, and an 86 percent
reduction in TN.
Lee and Song (2006) reported average removal of 81 percent COD, 92 percent SS, 68 percent
TN, and 95 percent TP using ozone to treat livestock wastewater through a dissolved air
flotation system in Korea. Separation, collection, and treatment of swine waste with an ammonia
recovery process using a metal ion treated resin bed achieved greater than 90 percent
reduction in ammonia content in North Carolina (Loeffler and van Kempen 2003). Removal of up
Chapter 2. Agriculture
2-47
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
to 90 percent of P from swine waste treated by chemical precipitation with struvite and
hydroxyapatite was reported in South Korea (Choi et al. 2008).
Table 2-7. Summary of reported practice effects resulting from other wastewater treatment
Location
Numerous
Ireland
Ireland
Korea
North
Carolina
Korea
Study
type
Review
Farm
Farm
Farm
Farm
Farm
Practice
Membrane
filtration
Recirculating
sand filter
Recirculating
sand filter
Ozone dissolved
air flotation
system
Separation +
ammonia
recovery3
Chemical
precipitation13
Practice effects
Ultrafiltration (0.01 jam) of manure: up to 100%
removal of coliform and SS, 87% P reduction, no
effect on soluble COD; lower efficiency from
microfiltration (0.2um: 75% SS removal.
For dairy wastewater, reported TN reduction of
27 to 41%; TN reduction increased to 83% when
sand filter effluent was recirculated through an
anoxic zone
For dairy wastewater, COD and TSS removals of
> 99%, and an 86% reduction in TN
Average removals of 81% COD, 92% SS, 68%
TN, and 95% TP removal from livestock
wastewater
Achieved > 90% reduction in ammonia content
in swine waste
Up to 90% removal of P from swine waste
Source
Masse et al.
2007
Healy et al.
2004
Healy et al.
2007
Lee and
Song 2006
Loeffler and
van Kempen
2003
Choi et al.
2008
Notes:
a. Ammonia recovery using a metal ion treated resin bed
b. Struvite and hydroxyapatite
Digestion
Anaerobic digestion of manure can offer substantial benefits, both economic and intangible, to
animal feeding operators and surrounding communities, such as renewable energy generation;
reduction in bulk and improvement of handling characteristics; production of stable, liquid
fertilizer and high-quality solid soil amendment; reduction in odors; reduction of greenhouse
gasses (GHGs); and reduction in ground and surface water contaminants (Demirer and Chen
2005; Cantrell et al. 2008; Garrison and Richard 2005). There is ample literature concerning
digester performance and yield, but not all studies report performance relevant to water quality
concerns. It should be noted that digestion does not generally remove nutrients from the original
waste material, and the residuals from digestion require further management.
2-48
Chapter 2. Agriculture
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
Costa et al. (2007) evaluated the efficiency of the anaerobic digestion in reducing the organic
load of swine waste. Results showed an average reduction of COD of 58 percent.
In Turkey, Gungor-Demirci and Demirer (2004) investigated the potential biogas generation
from anaerobic digestion of broiler and cattle manure. The efficiency of total COD removal was
32^3 percent and 40-50 percent for initial COD concentrations of 12,000 and 53,500 mg/L,
respectively. The biogas yields observed for initial COD concentrations of 12,000 and
53,500 mg/L were 180-270 and 223-368 ml_ gas/g COD added, respectively.
A thermochemical conversion process applied to the treatment of swine manure for oil
production in Illinois achieved a 75 percent reduction in COD (He et al. 2000). Lansing et al.
(2008a) reported 84 percent reduction in COD and a 78 percent increase in dissolved NH4-N
concentration in a study of seven low-cost digesters in Costa Rica. In a companion study of very
small farms, Lansing et al. (2008b) reported reductions in COD of 86 percent for dairy digester
and 92 percent for a swine digester.
Thermophilic aerobic digestion reduced volatile solids by 28-54 percent in Ireland, while
producing Class A biosolids suitable for land application (Layden et al. 2007). Anaerobic
digestion of poultry feces in Nigeria achieved greater than 99 percent reductions in E. coli
bacteria counts compared to an undigested, but equal-aged control (Yongabi et al. 2009).
In China, adding undigested swine wastewater to digested wastewater in a sequencing batch
reactor process significantly improved COD removal to greater than 80 percent and NH4-N
removal up to 99 percent (Deng et al. 2005). The effluent COD concentration was in the range
of 250 mg/L to 350 mg/L and effluent NH4-N concentration was less than 10 m/L. A pilot-scale
sequencing batch reactor built to treat swine waste in Australia achieved NH4-N and odor
reductions of greater than 99 percent as well as 79 percent removal of COD and a 49 percent
reduction of PO4-P on a mass balance basis because of struvite formation within the reactor
(Edgerton et al. 2000).
In China, enhancement of a traditional sequencing batch reactor for swine waste with two-step
feeding and low-intensity aeration at laboratory scale yielded reductions of 94 percent TN,
99 percent TP, and 99.9 percent BOD5, possibly reflecting the activity of denitrifying P-
accumulating organisms (Lue et al. 2008; Lu et al. 2009).
Chapter 2. Agriculture 2-49
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
Table 2-8. Summary of reported practice effects resulting from manure digestion
Location
Unknown
Turkey
Illinois
Costa
Rica
Costa
Rica
Ireland
Nigeria
China
Australia
China
Study
type
Farm
Pilot
Pilot
Farms
Farms
Farm
Farm
Farm
Pilot
Laboratory
Practice
Anaerobic
digestion
Anaerobic
digestion
Thermochemical
conversion
Anaerobic
digestion
Anaerobic
digestion
Thermophilic
aerobic digestion
Anaerobic
digestion
Sequencing
batch reactor
Sequencing
batch reactor
Enhanced
sequencing
batch reactord
Practice effects
Average reduction of COD of 58%.
For digestion of broiler and cattle manure,
COD removal was 32%-43% and 40%-
50% for initial COD concentrations of
12,000 and 53,500 mg/L, respectively. The
biogas yields observed for initial COD
concentrations of 12,000 and 53,500 mg/L
were 180-270 and 223-368 mL gas/g COD
added, respectively
75% reduction in COD of swine manure
84% reduction of COD; 78% increase in
NH4-N
86% reductions of COD for dairy digester
92% reductions of COD for a swine
digester
28%-54% reduction in volatile solids3
> 99% reductions in £. co/;*
Adding additional undigested swine
wastewaterto digested wastewater in a
sequencing batch reactor process
significantly improved with COD removal to
> 80% and NH4-N removal up to 99%
For swine waste, > 99% NH4-N and odor
reductions, 79% removal of COD, and a
49% reduction of PO4-P on a mass balance
basis0
Reductions of 94% TN, 99% TP, and
99.9% BOD5, possibly from growth of
denitrifying P-accumulating organisms
Source
Costa et al.
2007
Gungor-
Demirci and
Demirer2004
He et al. 2000
Lansing et al.
2008a
Lansing et al.
2008b
Layden et al.
2007
Yongabi et al.
2009
Deng et al.
2005
Edgerton et al.
2000
Lueetal. 2008;
Lu et al. 2009
Notes:
a. Produced Class A biosolids suitable for direct land application
b. Compared to an undigested, but equal-aged control
c. Due to struvite formation within the reactor
d. Addition of two-step feeding and low-intensity aeration to traditional SBR
2-50
Chapter 2. Agriculture
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
Composting
Composting of animal manure can reduce bulk, kill microorganisms, improve handling, and
provide a value-added product (Brodie et al. 2000). While significant quantities of N can be lost
through volatilization in the composting process (consider air quality issues), composting has no
net effect on the TP content of the material.
In Texas, Bekele et al. (2006) documented a 19-23 percent decrease in soluble P in streams
draining areas where significant quantities of manure had been composted and removed from
the watershed. While composting did not change the P content of the end product, composting
facilitated transport and marketing of the final product.
Gibbs et al. (2002) measured nutrient losses from aerobic composting of cattle manure in the
UK. Total mass loss ranged from 23 percent for an unturned static composting to 67 percent of
the initial mass for the indoor composting turned three times. N losses from the manure heaps
ranged from 8 to 68 percent of the initial total manure N content. Gaseous N losses, primarily as
NH3, accounted for between 7 and 67 percent of the initial manure N content.
Table 2-9. Summary of reported practice effects resulting from manure composting
Location
Texas
U.K.
Canada
Georgia
Study
type
Watershed
Farm
Farm
Farm
Practice
Composting +
export
Aerobic
composting
Aerobic
composting
Co-
composting
Practice effects
19%-23% decrease in soluble P in streams
draining areas where significant quantities of
manure had been composted and removed
from the watershed
23% mass loss for an unturned static
composting;
67% mass loss for the indoor composting
turned 3 times
Compost piles lost 8%-68% of initial TN;
gaseous N losses, primarily as NH3, accounted
for7%-67% of the initial manure N
Exposure to temperatures > 55 °C for 15 d
inactivated Giardia cysts and Cryptosporidium
oocysts in beef feedlot manure
Co-composting of chicken hatchery waste and
poultry litter was effective in eliminating 99.99%
of £. co/; bacteria
Source
Bekele et al.
2006
Gibbs et al.
2002
Larney and
Hao 2007
Das et al.
2002
In beef feedlot manure composting in Alberta, Canada, Larney and Hao (2007) reported that
exposure of manure to temperatures above 55 °C for a period of 15 days appears to be an
effective method of inactivating both Giardia cysts and Cryptosporidium oocysts in feedlot
Chapter 2. Agriculture
2-51
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
manure. The authors report mean carbon and N concentrations in eight feedlot manure
composts: total carbon 228 g/kg, TN 16.0 g/kg, soluble carbon11.3 g/kg, soluble N 1.6 g/kg.
Das et al. (2002) reported that co-composting of chicken hatchery waste and poultry litter was
effective in eliminating 99.99 percent of E. coli bacteria in Georgia. Koenig et al. (2005) reported
that alum and process controls such as moisture content, carbon source and particle size have
the potential to reduce NH3 loss from poultry manure composted inside high-rise layer structures.
Constructed wetland treatment
N in wastewater from dairy and swine operations has been successfully treated in constructed
wetlands (Hunt and Poach 2001). Plants are an integral part of wetlands. Cattails and bulrushes
are commonly used in constructed wetlands for nutrient uptake, surface area, and oxygen
transport to sediment. Improved oxidation and nitrification can also be obtained by using the
open water of marsh-pond-marsh designed wetlands. High levels of N removal by denitrification
have been reported from constructed wetlands, especially when the wastewater is partially
nitrified (Hunt et al. 2009). Manure solids must be removed before wetland treatment is
essential for the wetland to function long term.
A constructed wetland to treat incoming barnyard runoff in Ireland retained greater than
60 percent of the P load delivered to the wetland (Dunne et al. 2004). A subsequent study
(Dunne et al. 2005) reported that P retention by the wetland varied with season (5-84 percent)
with lowest retention occurring in winter.
In a review of 12 constructed wetlands treating livestock wastewater on the south coast of Ireland,
Harrington and Mclnnes (2009) reported that over an 8-year period, mean reduction of total and
soluble P exceeded 95 percent and the mean removal of ammonium-N exceeded 98 percent.
Mustafa et al. (2009) reported removal efficiencies of 98 percent BOD, 95 percent COD,
94 percent SS, 99 percent ammonia N, 74 percent NO3-N, and 92 percent soluble P in dairy
wastewater treatment through a constructed wetland system in Ireland.
Lee et al. (2004) reported that average reduction efficiencies in subsurface flow constructed
wetlands in Taiwan were SS 96-99 percent, COD 77-84 percent, TP 47-59 percent, and TN
10-24 percent. While physical mechanisms were dominant in removing pollutants, the
contributions of microbial mechanisms increased with the duration of wetland use, achieving
48 percent of COD removed and 16 percent of TN removed in the last phase. Water hyacinth
made only a minimal contribution to the removal of nutrients.
2-52 Chapter 2. Agriculture
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
In Kansas, Mankin and Ikenberry (2004) evaluated a constructed wetland without vegetation as
a sequencing batch reactor. Using 3-week batch periods without plants, overall mass removal
averaged 54 percent for COD, 58 percent for TSS, 90 percent for TN, 72 percent for NH4,
-54 percent for NO3, 38 percent for TP, and -8 percent for PO4.
Prantner et al. (2001) reported that a U.K. wetland system treating liquid swine manure after
soil infiltration removed 94 percent of the NH3-N and NH4-N, 95 percent of the NO3-N, and
84 percent of the TP.
Table 2-10. Summary of reported practice effects resulting from wetland treatment
Location
Ireland
Ireland
Ireland
Taiwan
Kansas
U.K.
Maryland
Nova
Scotia
Nova
Scotia
Vermont
Study
type
Farm
Review
Farm
Review
Wetland
Farm
Farm
Farm
Farm
Farm
Practice
Constructed
wetland
Constructed
wetland
Constructed
wetland
Constructed
wetlands
(subsurface flow)
Constructed
wetland without
vegetation
Constructed
wetland
Constructed
wetland
Constructed
wetland
Constructed
wetland
Subsurface flow
constructed
wetland with slag
filter
Practice effects
Retained > 60% of the P load delivered in
barnyard runoff; P retention by the wetland varied
with season (5%-84%) with lowest retention
occurring in winter
8-year mean reduction of total and soluble P
> 95% and the mean removal of ammonium-N
> 98%.
Removal efficiencies of 98% BOD, 95% COD,
94% SS, 99% ammonia N, 74% NO3-N, and 92%
soluble P in dairy wastewater treatment
Average reduction efficiencies in subsurface flow
constructed wetlands in Taiwan were SS 96-99%,
COD 77-84%, TP 47-59%, and TN 10-24%a
Mass removal averaged 54% COD, 58% TSS,
90% TN, 72% NH4, -54% NO3, 38% TP, and
-8% PO4
Treating liquid swine manure after soil infiltration
removed 94% of NH3-N and NH4-N, 95% of NO3-
N, and 84% of TP.
Treating dairy wastewater TN reduced 98%,
ammonia 56%, TP 96%, ortho-P 84%, SS 96%,
and BOD 97%; NO3/ NO2 increased 82%
Load reductions from 62-99% for BOD, TSS, TP,
and NH3-N treating agricultural wastewater
Load reductions of 54% TP and 53% soluble P
treating milkhouse wash water and liquid manure
Removed 75% of P mass from dairy barnyard
runoff and milk parlor waste
Source
Dunne et al.
2004, 2005
Harrington
and Mclnnes
2009
Mustafa et al.
2009
Lee et al.
2004
Mankin and
Ikenberry
2004
Prantner et
al. 2001
Schaafsma et
al. 2000
Smith et al.
2006
Wood et al.
2008
Weber et al.
2007
Note:
a. Physical mechanisms were dominant in removing pollutants; the contributions of microbial mechanisms increased with
the duration of wetland use. Water hyacinth made only a minimal contribution to the removal of nutrients.
Chapter 2. Agriculture
2-53
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
Flow of dairy wastewater through the wetland system in Maryland resulted in significant
reductions in concentrations of all analytes except NO3/ NO2 (Schaafsma et al. 2000). Relative
to initial concentrations, TN was reduced 98 percent, ammonia 56 percent, TP 96 percent,
ortho-P 84 percent, SS 96 percent, and BOD 97 percent. NO3/ NO2 increased by 82 percent,
although mean concentrations were much lower than concentrations of ammonia or TN.
In Nova Scotia, Smith et al. (2006) reported load reductions from 62 to 99 percent for BOD,
TSS, TP, and NH3-N in wetlands treating agricultural wastewater. Also in Nova Scotia, Wood et
al. (2008) reported mass reductions of 54 percent for TP and 53 percent soluble P over 4 years
in a surface flow constructed wetland milkhouse wash water and liquid manure. In Vermont, a
subsurface flow constructed wetland with a slag filter removed 75 percent of P mass from dairy
barnyard runoff and milk parlor waste (Weber et al. 2007).
Other biological treatment
A multiple-pond system (APS) treating dairy milking parlor effluent in New Zealand produced
effluent with 50-60 percent less BOD, TSS, TKN and ammonia-N than equivalently sized
two-pond systems with medians of 43, 87, 61, and 39 mg/L, respectively. TP was reduced by
70 percent to 19 mg/L. E. co//were reduced in the APS by two orders of magnitude to
918 MPN/100 ml_ (Bolan et al. 2009).
In Morocco, El Hafiane et al. (2003) reported average removals of 70 percent for N and
40 percent for P in a high-rate algal pond treating wastewater. Water hyacinth ponds were
reported to achieve approximately 50 percent removal of applied organic loads (COD, BOD, TN,
and TP) from swine waste in Brazil (Costa et al. 2000).
In Scotland, an algal-based bioreactor achieved sustained nutrient removal efficiencies (up to
99 percent and 86 percent for NH4-N and PO4-P, respectively) from swine wastewater while total
COD was removed up to 75 percent (Gonzalez et al. 2008). Lu et al. (2008) augmented a wetland
treating duck waste in China with water hyacinth and reported removal of 64 percent of COD,
22 percent TN, and 23 percent TP loads. The hyacinth was harvested and recycled as duck feed.
Anaerobically digested dairy manure effluent was treated with algal turf scrubber raceways in
Maryland (Mulbry et al. 2008). Removal rates of 70 to 90 percent of input N and P were
achieved at loading rates below one g TN, 0.15 g TP /m2/d; N and P removal rates decreased to
50-80 percent at higher loading rates.
2-54 Chapter 2. Agriculture
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
Table 2-11. Summary of reported practice effects resulting from other biological treatment
Location
New
Zealand
Morocco
Brazil
Scotland
China
Maryland
Hawaii
Study
type
Farm
Farm
Farm
Farm
Farm
Farm
Farm
Practice
Multiple pond
system
High-rate algal
pond
Water hyacinth
ponds
Algal bio-reactor
Water hyacinth
wetland
Algal turf
scrubber
Entrapped
mixed microbial
cells process
Practice effects
Treating dairy milking parlor effluent produced
effluent with 50%-60% less BOD, TSS, TKN
and ammonia-N than equivalently sized two-
pond systems. TP was reduced by 70% to
19 mg/L. E. coli reduced by two orders of
magnitude.
averaged removals of 70% N and 40% P
About 50% removal of applied organic loads
(COD, BOD, TN, TP) from swine waste
Removed 99% NH4-N, 86% of PO4-P, and 75%
of COD mass from swine wastewater
Removed 64% COD, 22% TN, and 23% TP
loads from duck waste3
Treating anaerobically digested dairy manure
effluent, removal rates of 70-90% of input N and
P were achieved at loading rates below 1 g TN,
0.15 g TP /m2/d; N and P removal rates
decreased to 50-80% at higher loading rates.
Removed 84% of COD and 98% of TP from
dilute swine wastewater
Source
Bolan et al.
2009
El Hafiane et
al. 2003
Costa et al.
2000
Gonzalez et
al. 2008
Lu et al.
2008
Mulbry et al.
2008
Yang et al.
2003
Note:
a. Water hyacinth was harvested and recycled as duck feed.
An entrapped mixed microbial cells process was used to investigate the simultaneous removal
of carbon and N from dilute swine wastewater in Hawaii (Yang, Chen et al. 2003). COD removal
efficiencies were 84 percent and TP removal efficiencies of 98 percent were achieved.
Air quality
Ammonia, dust, and odors associated with animal agriculture—especially on large facilities—
can be important local air pollutants. For example, Melse and Timmerman (2009) reported that
N emissions in exhaust air from pig houses in the Netherlands can represent as much as
25 percent of the TN excretion by the animals. Airborne ammonia can also become a significant
water pollutant when deposited in local waterbodies. Indoor air quality can affect animal health
as well, especially at large poultry and hog facilities. Animal production facilities can be
important producers of greenhouse gases (van der Meer 2008).
Chapter 2. Agriculture
2-55
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
Ullman et al. (2004) reviewed abatement technologies available to reduce atmospheric
emissions from animal production facilities and summarized the following:
• Scrubbers have been shown to reduce odors by 60-85 percent and to reduce ammonia
by 15-45 percent.
• Filter systems can reduce airborne dust from broiler operations by up to 50 percent.
• Biofilters can exhibit 90 percent or better reductions of odor-causing chemicals such as
hydrogen sulfide, methanethiol, dimethyl sulfide, and dimethyl disulfide.
• lonization systems can reduce dust concentrations 68-92 percent.
• Indoor ozone systems can decrease total dust concentrations by 60 percent and
ammonia levels by 58 percent compared to similar buildings without ozone treatment.
The authors added that poultry litter amendments such as sodium bisulfate and alum can
reduce odor and ammonia emissions and natural windbreaks can provide an entrapment
mechanism for odorous compounds that require minimal maintenance. Windbreaks placed
downwind of exhaust fans and litter storage areas can provide an economical management
practice for broiler producers when used in conjunction with other air-cleaning practices.
In Kentucky, Singh et al. (2009) reported that adding a commercially available urease inhibitor
to poultry litter resulted in a significant reduction in equilibrium ammonia concentration over time
by disrupting the enzymatic degradation of uric acid.
Melse and Timmerman (2009) reported average ammonia removal efficiencies of 70-96 percent
for farm-scale operated acid scrubbers on swine facilities in the Netherlands. Reported average
removal efficiency for odor was only 31 percent and showed a large variation. Multi-pollutant
scrubbers removed an average of 66 percent of ammonia, 42 percent of odor, 50 percent of
PM10, and 57 percent of PM2.s.
Adrizal et al. (2008) evaluated the potential of trees planted around Pennsylvania commercial
poultry farms to trap ammonia and dust or particulate matter. Results indicated that poplar,
hybrid willow, and Streamco willow are appropriate species to absorb poultry house aerial NH3-
N, whereas spruce and hybrid willow are effective traps for dust and its associated odors.
Koenig et al. (2005) reported that alum and process controls such as moisture content, carbon
source and particle size have the potential to reduce ammonia loss from poultry manure
composted inside high-rise layer structures. Although both low moisture and temperature
reduced NH3 capture, managing temperature and moisture to achieve low NH3 would adversely
affect microbial activity and other desired benefits of composting.
2-56 Chapter 2. Agriculture
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
In a Texas laboratory study, Shi et al. (2001) evaluated amendments for reducing ammonia
emissions from open-lot beef cattle feedlots and found that cumulative ammonia emissions after
21 days compared to the untreated control were 2-8 percent for alum, 22-29 percent for CaCI2,
32-40 percent for humate, 34-36 percent for a urease-inhibitor NBPT, and 68-74 percent for a
commercial product.
In North Carolina, Szogi and Vanotti (2007) demonstrated that solid-liquid separation
technologies can substantially reduce ammonia emissions from anaerobic swine lagoons.
Ammonia emissions from a lagoon with solid-liquid separation had 73 percent lower ammonia
emissions compared to an anaerobic lagoon.
Table 2-12. Summary of reported practice effects for air quality issues
Location
Numerous
Netherlands
Pennsylvania
Texas
North
Carolina
North
Carolina
Study
type
Review
Farm
Farm
Laboratory
Farm
Farm
Practice
Various
Acid
scrubbers
Tree
windbreaks
Beef feedlot
amendments
Liquid-solid
separation
Aerobic
lagoon
Practice effects
Scrubbers can reduce odors by 60%-85% and
reduce ammonia by 15%-45%
Filter systems can reduce airborne dust from
broiler operations by up to 50%
Biofilters can exhibit 90% or better reductions
of odor-causing chemicals
lonization systems can reduce dust
concentrations 68%-92%
Indoor ozone systems can decrease total dust
concentrations by 60% and ammonia levels by
58% compared to similar buildings without
ozone treatment
Average 70%-96% ammonia removal, 31%
odor removal on swine facilities; multi-pollutant
scrubbers removed 66% of ammonia, 42%
odor, 50% PM10 removal, and 57% PM25
Poplar, hybrid willow, and Streamco willow
absorb poultry house aerial NH3-N; whereas
spruce and hybrid willow are effective traps for
dust and odors.
21 -day cumulative ammonia emissions
compared to untreated control were: 2%-8%
for alum, 22%-29% for CaCI2, 32%-40% for
humate, 34%-36% for a urease-inhibitor
NBPT, and 68%-74% for a commercial
product.
Ammonia emissions from a lagoon with solid-
liquid separation had 73% lower ammonia
emissions compared to an anaerobic lagoon.
Reduced GHG emissions 96.9%, from 4,972 t
to 1 53 1 of carbon dioxide equivalents
(C02-eq)/yr
Source
Ullman et al.
2004
Melse and
Timmerman
2009
Adrizal et al.
2008
Shietal.
2001
Szogi and
Vanotti 2007
Vanotti et al.
2008
Chapter 2. Agriculture
2-57
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
Replacing swine waste lagoon technology with cleaner aerobic technology in North Carolina
reduced GHG emissions 96.9 percent—from 4,972 metric tons (MT) to 153 MT of carbon
dioxide equivalents (CO2-eq)/yr (Vanotti et al. 2008).
Practice Costs
Systematic cost data for most practices are rarely given in the scientific literature; better cost
data might be available on a state or county basis from producers, groups, or agencies funding
or managing implementation. Among reported cost data, there is a lack of consistency in unit
costs (e.g., $/cow, $/kg P removed, or $/!_ of waste treated) that sometimes makes comparison
among practices difficult. Cost figures are reported in dollars for the year given by the authors.
In laboratory studies, Jones and Brown (2000) estimated chemical cost (2010 dollars) for
combinations of alum and PAM of $74-200/kg ortho-P removed from dairy wastewater. For
supplementary precipitation of soluble P in the treatment of dairy manure by mechanical
separation, Oh et al. (2005) estimated costs for alum and polymer addition of about $3.21 per
1,000 L (2010 dollars) of treated manure slurry.
Moore et al. (2000) found that alum applications to poultry litter was cost-effective, with a
benefit/cost ratio of 1.96 partly from heavier birds, better feed conversion, and lower energy use
to vent ammonia from the houses.
In a cost analysis of anaerobic digestion and methane production, Garrison and Richard (2005)
noted that the economic feasibility of the energy conversion technology varies widely with scale,
with significant advantages for larger facilities. Farrow-to-finish and finishing swine operations
needed more than 20,000 head and 5,000 head, respectively, to be economically feasible. Dairy
operations in the midwestern United States hold considerably more economic promise, with
feasible herd counts in the 150- to 350-head range for electricity prices of $0.13/kWh (2010
dollars). Results indicate that increased energy prices and financial assistance will be needed to
encourage significant numbers of facilities to recover energy from manure.
In Virginia, covered lagoon anaerobic digesters run from about $112/head for swine to about
$318/head for dairy, with plug-flow digesters for dairy costing just under $700/head (USDA-
NRCS 2010). Typical total costs are about $112,000 for covered lagoons for swine, $240,000
for covered lagoons for dairy, and just over $512,000 for plug-flow anaerobic digesters for dairy.
Brodie et al. (2000) studied technologies to manufacture compost from poultry litter and
reported that screened compost was produced at an operational cost of $37 (2010 dollars) while
unscreened compost could be produced for about $25 per ton of compost. A production scheme
2-58 Chapter 2. Agriculture
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
where poultry litter is a static pile composted on farms for later transport to regional processing
centers appeared feasible.
Kemper and Goodwin (2009) reported that in composting poultry litter and eggshell waste into a
marketable soil amendment, compost could be produced at an average cost of $17.73 to
$20.38/ton (2010 dollars) for small-scale and large-scale systems, respectively. The cost for
disposing of eggshell waste in landfills was $25.36/ton (2010 dollars).
Static pile/windrow composting facilities with a concrete floor that are used for vegetative
materials cost about $55/yd3, with typical facilities costing about $18,100 (USDA-NRCS 2010).
Animal mortality composting facilities cost about $330/yd3 for either poultry or swine. Typical
dead-poultry composting facilities cost about $12,000, whereas typical dead-swine composting
facilities cost much more—about $35,000. A static pile/window composter with a concrete floor
for animal mortality is a lower cost option that runs about $107/yd3, with typical total costs of
under $9,500. Larger (1,500-lb capacity) dead-animal incinerators cost about $10.60 per pound
of capacity, while smaller incinerators (400-lb capacity) cost $23.44 per pound of capacity, with
typical costs of about $16,000 and $9,500 each for larger and smaller incinerators, respectively.
Gasification units are a higher-end option for dead animals, ranging from just over $58 to nearly
$150 per pound of capacity, with units typically costing $40,000 to $70,000 depending on size.
Even more expensive are forced aeration composters. They can cost from about $900 to
$1,300/yd3 depending on capacity and whether a grinder is included, with typical facility costs
ranging from about $130,000 each to just over $250,000 each.
In a study of using filamentous green algae grown in outdoor raceways to treat dairy manure
effluent, Mulbry et al. (2008) projected annual operational costs of $788 per cow (2010 dollars).
For comparison, the operational costs of $11.12 per kg N removed are well below the costs
cited for upgrading existing water treatment plants.
Vegetative environmental buffers (strategically planted trees and shrubs) around poultry houses
cost $4.05/ft in the form of containerized plants, with typical costs reaching $4,055 in Virginia
(USDA-NRCS 2010). Windbreaks or shelterbelts consisting of pines, hardwoods, and mixed
shrubs cost $82.50, $909, and $1,453 per acre, respectively, with respective typical total costs
of $41.25, $456, and $726.
Shi et al. (2001) calculated the costs of six amendments for reducing ammonia emissions from
open-lot beef cattle feedlots, ranging from $0.15 to $6.81 (2010 dollars) per application per
head. Only one treatment had a benefit/cost ratio greater than 1.0. Results suggest that
amendments can reduce ammonia emissions from open feedlots, but the costs might be
prohibitive.
Chapter 2. Agriculture 2-59
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
Vanotti et al. (2008) analyzed GHG emission reductions from implementing aerobic technology
on swine farms in North Carolina and estimated emission reductions of 4,776.6 MT CO2-eq per
year or 1.10 MT CO2-eq/head per year. The dollar value from implementation was $19,312/year
(2010 dollars) using current Chicago Climate Exchange trading values of $4.04/t CO2 (2010
dollars). That translates into a direct economic benefit to the producer of $1.77 (2010 dollars)
per finished pig. The authors suggest that GHG emission reductions and credits can help
compensate for the higher installation cost of cleaner aerobic technologies and facilitate
producer adoption of environmentally superior technologies to replace current anaerobic
lagoons.
In studies of poultry litter amendments to reduce odor and ammonia volatilization, Ullman et al.
(2004) found that sodium bisulfate and alum treatments ranged in price from $253 to $530 per
ton (2010 dollars), resulting in a cost of $13 to $18 for 92.9 m2 (1,000ft2) at recommended
application rates. Another cost benefit analysis showed that ammonia reduction by ventilation
during cold periods would cost $4,400 per flock (19,000 birds weighing four Ib each).
Unit and typical total costs for various amendments to treat agricultural waste are the following
(USDA-NRCS2010):
• Ferric sulfate or alum for broiler house litter: $0.199/ft2, $3,750 total
• Ferric sulfate or alum for turkey or rooster house litter: $0.159/ft2, $3,000 total
• Liquid alum treatment for very dry broiler house litter: $0.268/ft2, $5,060 total
• Liquid alum treatment for turkey or rooster house litter: $0.214/ft2, $4,050 total
• Sodium bisulfate treatment for broiler house litter: $0.205/ft2, $3,880 total
• Sodium bisulfate treatment for turkey or rooster house litter: $0.164/ft2, $3,100 total
2-60 Chapter 2. Agriculture
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
3 Implementation Measures and Practices for
Cropland In-Field Control
The best approach to minimize nutrient transport to local waters depends on whether the
nutrient is in the dissolved phase or is attached to soil particles. For dissolved nutrients,
effective management includes source reduction and reduction of water runoff or leaching.
Erosion and sediment transport controls are necessary to reduce transport of nutrients attached
to soil particles. Practices that focus on controlling the transport of smaller soil particle sizes
(e.g., clays and silts) are most effective because they are the soil fractions that transport the
greatest share of adsorbed nutrients.
3.1 Field Nutrient Management
Strategies for in-field control on cropland focus on managing the form, application method, and
timing of waste and nutrient applications and on controlling soil conditions to reduce the
potential for runoff of nutrients. Pasture management strategies address managing animal
stocking rates and timing as well as maintaining vigorous vegetation to provide for soil stability
and nutrient recycling.
Implementation Measure A-10:
Manage nutrient applications to cropland to minimize nutrients available for runoff.
In doing so
• Apply manure and chemical fertilizer during the growing season only
• Do not apply any manure or fertilizer to saturated, snow-covered, or
frozen ground
• Inject or otherwise incorporate manure or organic fertilizer to minimize
the available dissolved P and volatilized N
• Apply nutrients to HELs only as directed by the nutrient management
plan, while at the same time implementing all aspects of the soil
conservation plan
In many crop areas, nutrient imports into the watershed from feed and fertilizers exceed nutrient
exports in crops and livestock produced; that imbalance often exists at both the individual field
and the watershed level (Beegle 2000). In such circumstances, nutrients can accumulate in
soils from over-application of fertilizer or animal waste relative to crop need. Excessive soil
Chapter 2. Agriculture 2-61
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
nutrient levels have been linked to high P losses in runoff and leaching losses of N, especially in
areas of animal-based agriculture.
Nutrient management is an important tool to match nutrient inputs more closely to crop needs.
The USDA-NRCS Nutrient Management Practice (NRCS Practice Code 590) generally defines
nutrient management as, "managing the amount, source, placement, form and timing of the
application of nutrients and soil amendments." The Nutrient Management Practice can be
applied for a number of purposes:
• To budget and supply nutrients for plant production
• To properly use manure and organic byproducts or biosolids as a plant nutrient source
• To minimize agricultural nonpoint source pollution of surface and ground water resources
• To protect air quality by reducing N emissions and the formation of atmospheric
particulates
• To maintain or improve the physical, chemical, and biological condition of soil
This section presents information concerning several management practices to manage
nutrients on cropland to reduce nutrient losses:
• Manure and fertilizer form and rate—selecting the form (N and P amounts in solid,
semi-solid, or liquid manure) and rate of nutrients applied to cropland to reduce runoff or
leaching losses
• Nutrient application methods and timing—selecting the method and timing of manure
or fertilizer application to cropland to support crop growth and reduce runoff or leaching
losses
• Nutrient management planning—preparing and implementing a comprehensive plan to
manage nutrients from all sources to provide for crop growth while minimizing runoff and
leaching losses of nutrients
• Soil and manure amendment—treating soils or manure to reduce the availability or
mobility of nutrients
Using the products and methods described in this section should be considered carefully
relative to existing practices because timing and placement of fertilizers play an important role in
maximizing NUE. For example, if a producer replaces side dressing with use of a urease
inhibitor, the timing and fertilizer placement must be a factor in the decision to switch. Also,
emerging technologies will allow producers who use no-till on their cropland to inject manure so
that no-till is continuous. That type of technology is welcome and should continue to be
developed and widely implemented.
2-62 Chapter 2. Agriculture
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
Reference documents are available that provide guidance on selection of practices with
consideration for fertilizer source as well as timing, placement, and rate of application. Some
examples are listed below (all Web sites were accessed April 24, 2010). Other regional- or
state-specific guidance should be available from NRCS Field Offices and Land Grant
Universities in each state.
• EPA's National Management Measures for the Control of Nonpoint Pollution from
Agriculture
• NRCS Agricultural Waste Management Field Handbook
• extension Resource Areas including Animal Manure Management and several industry-
specific resource areas (http://www.extension.org/main/communities)
• Fertilizer Nitrogen BMPs to Limit Losses that Contribute to Global Warming (Snyder
2008)
• Best Management for Fertilizers on Northeastern Dairy Farms (Bruulsema and
Ketterings 2008)
• Optimizing Nitrogen Fertilizer Decisions (Nielsen 2001)
• Cornell University's Whole Farm Nutrient Management Tutorials
(http://instruct1.cit.cornell.edu/Courses/css412/index.htm)
• Penn State Cooperative Extension Nutrient Management Planning Tools and Resources
(http://panutrientmgmt.cas.psu.edu/main planning tools.htm)
• Penn State Agronomy Guide, Section 2 Soil Fertility Management,
(http://agguide.agronomy.psu.edu/cm/sec2/sec2toc.cfm)
• Delaware Nutrient Management Program Publications and Resources
(http://dda.delaware.gov/nutrients/NM Pubs resources.shtml)
• University of Maryland Agricultural Nutrient Management Program
(http://anmp.umd.edu/)
• West Virginia University Extension Service Nutrient/Waste Management Web page
(http://www.wvu.edu/~agexten/wastmang/index.html)
EPA encourages producers to consult with crop advisors, nutrient management planners,
NRCS Field Offices and Cooperative Extension Services for assistance in evaluating the
relative costs and benefits of a particular practice or system.
Chapter 2. Agriculture 2-63
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
Practice Effectiveness
Manure and fertilizer form and rate
Chien et al. (2009) reviewed recent developments of fertilizer production and use that improve
nutrient efficiency and minimize environmental impact. Improving N use efficiency includes
using the following:
• Controlled-release coated urea products
• Nitrification inhibitors (Nl) to reduce NO3 leaching and denitrification
• Urease inhibitors to reduce ammonia hydrolysis from urea, with subsequent volatilization
• Ammonium sulfate to enhance N efficiency of urea by reducing ammonia volatilization
from urea
As indicated above, field conditions and relative benefits must be carefully considered when
evaluating use of these products to improve N use efficiency. Nielsen (2006) reports that, even
when compared to urease inhibitors or nitrification inhibitors, using a more traditional sidedress
application strategy remains one of the easiest and least expensive ways to maximize N use
efficiency because other application methods need to be carefully matched to the N fertilizer
source to minimize the risk of N loss before plant uptake.
Little research is available that directly compares the effectiveness of ammonium sulfate versus
urease inhibitors in reducing ammonia volatilization from urea. A widely used and intensively
researched urease inhibitor has been shown to reduce ammonia volatilization by an average of
60 percent compared to urea alone (Cantarella et al. 2005). Other studies (Fleisher and Hagin
1981, Kumar and Aggarwal 1998, and Goos and Cruz 1999) found that application of
ammonium sulfate 2 to 4 weeks in advance of urea reduced ammonia volatilization by
approximately 50 percent.
Practicality and cost are also important considerations. Goos and Cruz (1999) suggest that
application of ammonium sulfate in advance of urea could be limited in practical application
because it is not always possible to replicate the fertilizer applications in the same field location.
Other studies (Lara-Cabezas et al. 1992, 1997; Oenema and Velthof 1993; Vitti et al. 2002)
suggest that substituting ammonium sulfate for part of the urea mixture at application could be
effective in reducing ammonia volatilization but as Chien et al. (2009) point out this use must be
weighed in terms of its relative cost including an increase in the transportation cost for
ammonium sulfate compared to urea because ammonium sulfate contains less N.
Chien et al. (2009) report that slow-release urea-aldehyde polymer fertilizers are generally more
efficient than soluble N sources when the gradual supply of N is an advantage to crops. Under
2-64 Chapter 2. Agriculture
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
certain conditions, however, using slow-release urea-aldehyde polymer products might provide
no production advantage. For example, Cahill et al. (2007) reported that grain yield and N use
efficiency with urea NH4NO3 solution was statistically similar to or better than with urea
formaldehyde polymer. Shaviv (2005) reports that the high cost of slow-release polymers limits
their use in agriculture, but the potential for increased use is high where the products have been
shown to increase nutrient recovery, sustain high yields, and reduce nutrient losses and
associated environmental impacts based on reduced application levels and the ability to match
release characteristics with plant demand. Bundick et al. (2009) describe advantages for the
use of controlled-release fertilizers including reduced leaching, denitrification or volatilization
losses, and more uniform crop growth because of reduced risk of seedling burn or salt damage.
Disadvantages include cost, ineffectiveness when a quick release is needed (e.g., when side
dressing corn at the 6-leaf stage).
Using urea supergranules for deep placement has been shown to improve N use efficiency
used in small-scale rice production where plants are fertilized by hand. If problems related to
labor cost and difficulty in deep placement of urea supergranules in upland soils can be solved,
Chien et al. (2009) expect that deep placement of urea supergranules should also perform well
as an N source for upland food crops.
Using nonconventional P fertilizers includes phosphate rock (PR) for direct application, a
mixture of PR and water-soluble P sources, and nonconventional acidulated P fertilizers
containing water-insoluble P compounds (Chien et al. 2009). PR has been studied for
agronomic use for more than 50 years and can be agronomically beneficial depending on the
solubility of PR, soil properties, management practices, climate, and crop species. For example,
is most effective where the PR is highly reactive and when used in acidic soils or tropical
climates. Several decision support systems (PRDSS) have been developed to help integrate
such factors to evaluate the effectiveness of PR for direct application under specific conditions.
Where use of PR is not as feasible as water-soluble P sources, PR can be mixed with water-
soluble P sources to economically achieve the same results as use of the water-soluble P
source or PR alone because the water-soluble P source has a starter effect that allows for
better initial root development, resulting in more effective PR utilization. Recent research has
focused on eutrophication reduction when PR is used to replace water soluble P sources as well
as the use of PR in organic farming. Several studies have been conducted under controlled
conditions to determine the relative effectiveness of nonconventional acidulated fertilizers made
from lower quality PR ore compared to those with a higher proportion of water-soluble P. The
review stresses that additional field studies are needed to adequately evaluate the agronomic
use of PR under a variety of conditions.
Chien et al. (2009) indicate that using fluid P fertilizers can improve the efficiency of
conventional P fertilizers, although additional research is needed. Recent research in Australia
Chapter 2. Agriculture 2-65
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
indicates that fluid P fertilizers were more effective than the commercial granular P fertilizers
using the same P compound in increasing crop yield in calcareous and alkaline soils (Holloway
et al. 2001) and that total and labile phosphorus from fluid sources diffused further into the soil
than when granular sources are used (Hettiarachchi et al. 2006; Lombi et al. 2004). However, a
number of earlier studies also showed no difference in phosphorus use efficiency between liquid
and granular forms.
Slow-release fertilizer (SRF) and controlled-release fertilizer (CRF) materials can improve
nutrient uptake efficiency and reduce the leaching potential of nutrients (Morgan et al. 2009).
Those considerations are particularly important for crops grown on sandy soils with relatively
low nutrient- and water-holding capacities.
In New Zealand, Sojka (2009) compared the efficacy of matrix-based fertilizers (MBFs)
formulated to reduce NO3, ammonium, and TP leaching with conventional SRFs, and an
unfertilized control. SRF leachate contained higher amounts of NO3, ammonium, and TP than
leachate from all other fertilizers. There were no consistent differences in the amount of NO3,
ammonium, and TP in the MBF leachates compared to the control leachate.
Penn et al. (2004) tested the effects of phytase enzyme and HAP corn supplemented diets on
runoff P concentrations from Virginia pasture soils receiving surface applications of turkey
manure. The alternative diets caused a decrease in manure total and water-soluble P compared
with the standard diet. Runoff dissolved P concentrations were significantly higher from HAP
manure-amended soils while dissolved P losses from other manure treatments were not
significantly different from each other.
In a laboratory study, Loria and Sawyer (2005) compared the effect of raw and digested liquid
swine manure application on soil test P and inorganic N. Raw and digested manure produced
the same NH4-N disappearance, NO3-N formation, net inorganic N, and an increase in soil test
P. Routine soil test P methods estimated similar P recovery with both manure sources.
In Iowa, Loria et al. (2007) found no difference between raw swine manure and manure
digested for biogas as a source of N for plant use in the year of application or in the residual
year; equivalence to fertilizer N was the same with both raw and digested swine manure.
In Georgia, Risse and Gilley (2000) reported that runoff was reduced from one to 68 percent,
and soil loss decreased from 13 to 77 percent for locations on which manure was added
annually. Measured runoff and soil loss values were found to be strongly influenced by manure
application rates. Regression equations were developed relating reductions in runoff and soil
loss to manure application rates.
2-66 Chapter 2. Agriculture
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
In Colorado, Shoji et al. (1999) conducted field trials on CRFs and an Nl to show their potential
to increase NUE. TN fertilizer losses averaged 15 and 10 percent in the Nl and urea treatments,
respectively. On the other hand, those from the CRF treatment averaged only 1.9 percent,
indicating that CRF showed the highest potential to increase N use efficiency.
King and Torbert (2007) designed an Ohio plot study to compare temporal losses of NO3-N and
NH4-N from three SRFs (sulfur-coated urea, composted dairy manure, and poultry litter) and
one fast-release fertilizer (NH4NO3) applied to Bermuda grass turf. Cumulative NO3-N loss from
plots receiving application of the manufactured (NH4NO3 and sulfur-coated urea) products was
significantly greater than the measured losses from plots receiving application of composted
dairy manure and poultry litter. The cumulative NO3-N recovered in the runoff expressed as a
proportion of applied N was 0.37 for NH4NO3, 0.25 for sulfur-coated urea, 0.10 for composted
dairy manure, and 0.07 for poultry litter.
Table 2-13. Summary of reported practice effects resulting from management of manure and
fertilizer form and rate
Location
New
Zealand
Brazil
North
Carolina
Australia
Study
type
Plot
Field
Field
Field
Practice
Fertilizer
formulation
Urease
inhibitor
Slow-release
urea
formaldehyde
polymer
Fluid P
fertilizer
Practice effects
Leachate from conventional SRFs contained
higher amounts of NO3, ammonium, and TP than
leachate from all other fertilizers
The percentage of reduction in volatilization due
to NBPT application ranged from 15% to 78%
depending on the weather conditions during the
days following application of N. Addition of NBPT
to urea helped to control ammonia losses, but
the inhibitor was less effective when rain
sufficient to incorporate urea into the soil
occurred only 10 to 15 days or latter after
fertilizer application.
In all cases aqueous urea ammonium nitrate
(DAN) outperformed or was statistically similar to
urea formaldehyde polymer (UFP). UFP would
only be economically viable if priced similar to
DAN. UFP released N on a time scale similar to
DAN (1 to 2 weeks). Similarity of the two N
sources might have been because the release
rate of UFP might not be optimal for the crops or
varieties at the chose application timings.
70 of 1 03 wheat experiments showed positive
yield increases compared to granular P sources
when fluids were applied over calcareous soils.
The positive increase rate with fluids was much
greater when micronutrients were applied in
solution with P and N.
Source
Sojka 2009
Cantarella et
al. 2005
Cahill etal.
2007
Holloway et
al. 2001
Chapter 2. Agriculture
2-67
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
Table 2-13. Summary of reported practice effects resulting from management of manure and
fertilizer form and rate (continued)
Location
Australia
Virginia
Iowa
Iowa
Georgia
Colorado
Ohio
Study
type
Laboratory
Field
Plot
Plot
Fields
Field trials
Plot
Practice
Fluid P
fertilizer
Poultry litter
from phytase
and HAP
feeding
Slow release
fertilizers
Raw vs.
digested
swine manure
Manure
application
rates
CRF, NIs
SRFs
Practice effects
When P is supplied in granular form, P diffusion
and isotopic lability in calcareous soils are
reduced compared with equivalent liquid fertilizer
formulations, probably due to precipitation
reactions induced by osmotically induced flow of
soil moisture into the fertilizer granule.
Alternative diets decreased manure total and
water-soluble P compared with the standard diet.
Runoff dissolved P concentrations were
significantly higher from HAP manure-amended
soils than from phytase manure applications,
while dissolved P losses from other manure
treatments were not significantly different from
each other.
Raw and digested manure produced the same
NH4-N disappearance, NO3-N formation, net
inorganic N, and an increase in soil test P.
Routine soil test P methods estimated similar P
recovery with both manure sources.
No difference between raw swine manure and
manure digested for biogas as a source of N for
plant use in the year of application or in the
residual year; equivalence to fertilizer N was the
same with both raw and digested swine manure.
Runoff was reduced from 1%-68%, and soil loss
decreased from 13%-77% where manure was
added annually. Measured runoff and soil loss
values were found to be strongly influenced by
manure application rates; regression equations
were developed relating reductions in runoff and
soil loss to manure application rates.
TN fertilizer losses averaged 15% and 10% in
the Nl and urea treatments, respectively. N
losses from the controlled release fertilizer
treatment averaged only 1 .9%
Cumulative NO3-N loss from plots receiving
application of manufactured (NH4NO3 and sulfur-
coated urea) products was significantly greater
than the measured losses from plots receiving
application of composted dairy manure and
poultry litter. The cumulative NO3-N recovered in
the runoff expressed as a proportion of applied N
was 0.37 for NH4NO3, 0.25 for sulfur-coated
urea, 0.10 for composted dairy manure, and 0.07
for poultry litter.
Source
Hettiarachchi
et al. 2006;
Lombi et al.
2004
Penn et al.
2004
Loria and
Sawyer 2005
Loria et al.
2007
Risse and
Gilley2000
Shoji et al.
1999
King and
Torbert 2007
2-68
Chapter 2. Agriculture
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
Nutrient application methods and timing
In soil column and field studies in New York, Geohring et al. (2001) reported that high P
concentrations observed in tile drain effluent soon after dairy manure application can be
attributed to macropore transport processes. Plowing-in manure apparently disturbs these
macropores and promotes matrix flow, resulting in greatly reduced P concentrations in the
drainage effluent.
In New York, Lewis and Makarewicz (2009) reported significant decreases in winter
concentrations of TP, soluble P, TKN, and NO3-N but not TSS following cessation of winter dairy
manure application to cropland.
Chen and Samson (2002) investigated the effects of fertilizer source and manure application
timing, rate, and method on soil nutrient concentrations, corn grain yields, and groundwater NO3
concentrations in Ontario, Canada. In general, higher NO3-N concentrations were observed in
those plots where N sources had been applied shortly before soil sampling. Trends of residual
NO3-N concentrations varied among experiments, and results were inconclusive. Two-fold
higher P concentrations were observed in the manured plots than in the inorganically fertilized
plots as a result of higher P2O5 inputs from swine manure.
In Kansas plots, Reiman et al. (2009) tested the effect of manure placement depth on corn and
soybean yield and N retention in soil. The net effect of placement on TN was that deep manure
injection treatments had 31-59 more kg N/ha than the shallow injection treatment 12 to 30
months after application. Higher corn yield in the deep-injected treatment was attributed to
increased N use efficiency. Higher inorganic N amounts in the deep injection treatment were
attributed to reduced N losses through ammonia volatilization, leaching, or denitrification.
AN et al. (2007) tested simplified surface irrigation of dairy farm effluents in Quebec, Canada,
and reported that seepage losses represented less than one percent of the total volume of
effluents (nutrients and bacteria) applied; nutrients and bacteria applied were lost in subsurface
drainage, implying a treatment efficiency of greater than 99 percent compared to conventional
land spreading.
On-farm trials were conducted near Ottawa, Ontario, to determine the effect of preplant and
sidedress fertilizer N application on corn yield, N uptake and N2O gas emission (Ma 2007). Data
showed that for each kg N applied, 70-77 kg ha"1 of yield was produced for sidedress compared
to 46-66 kg of yield for preplant N application. When the same amount of fertilizer was applied,
significantly greater yield (7.6-10.6 percent) was produced with sidedress than preplant N
application. Ebelhar et al. (2009) tested nine different N sources in part to determine the N use
efficiencies for new fertilizer technologies and evaluate their effects on crop yields. In general,
Chapter 2. Agriculture 2-69
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
for wet sites, the sidedress injection of N provided the highest corn yields and best N use
efficiencies (with a polymer coated urea product second). Note that the sidedress treatment at
dry locations appear to be a detriment, likely because dry conditions prevented N from reaching
the corn roots when needed.
Harmel et al. (2004) conducted a paired watershed study to evaluate the impact of variable rate
N fertilizer application on surface water quality. Few water quality differences were observed
during the first year, but overall median NO3 + NO2-N concentrations were significantly lower for
the variable rate field receiving sidedress N applications in the second year.
In an Ontario, Canada, plot study, Coelho et al. (2006) determined the effects of rate and
method of sidedress application of liquid swine manure on N recovery by corn using in-row
injection ortopdressing to sidedress manure. Coelho et al. (2006) measured grain N uptake and
NO3-N in drainage water, stalks, and topsoil postharvest. Apparent recovery of manure TN was
greater with injection (59 percent) than topdress (41 percent) and transport of N to groundwater
and surface water was minimized when side dressed at or below rates for optimal yield. When
injected N exceeded crop demand, NO3-N increased to more than 10 mg/kg in topsoil, 20 mg/L
in drainage water, and to excessive (3.6 g/kg) levels in stalks.
Drainage NO3-N concentration and load increased linearly by 0.69 mg NO3-N/L and 4.6 kg NO3-
N/ha, respectively, for each 10 kg N/ha applied over the minimum of 275 kg N/ha in trials of
swine waste application to corn in Spain (Dauden et al.2004). An increase in irrigation efficiency
did not induce a significant increase of leachate concentration and the amount of NO3 leached
decreased about 65 percent. Application of low manure doses before sowing complemented
with side dressing N application and good irrigation management were found to be key factors
to reduce NO3 contamination of water courses.
Hebbar et al. (2004) compared fertigation with various fertilizer sources, rates, and application
methods with drip- and flood-irrigated controls in a red sandy loam soil in India. They found that
fertigation with 100 percent water-soluble fertilizer (WSF), subsurface drip fertigation, N-
potassium fertigation, and half soil-half fertigation increased the hybrid tomato yield significantly
over the controls. Significant yield reduction was recorded with 75 percent rate fertigation and
normal fertilizer fertigation compared to WSF fertigation. WSF fertigation resulted in a
significantly higher number of fruits per plant and fertilizer use efficiency compared to drip- and
furrow-irrigated controls. Fertigation also resulted in less leaching of NO3-N and K to deeper soil
layers. Subsurface drip fertigation resulted in higher assimilable P in deeper soil layers. Root
growth and NPK uptake was increased by WSF fertigation. Tan et al. (2003) studied the effects
of drip irrigation and fertigation on yield, quality, and water and NUE of tomatoes. They found no
significant difference in marketable tomato yields between broadcast fertilizer and fertigation for
both subsurface and surface drip irrigation on a loamy sand soil.
2-70 Chapter 2. Agriculture
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
Various micro-irrigation systems were used to evaluate the impact of fertigation and soil type on
the potential for NO3 leaching to groundwater (Gardenas et al. 2005). Seasonal leaching was
found to be highest for coarse-textured soils. Modeling also showed that fertigation at the
beginning of the irrigation cycle tends to increase seasonal NO3 leaching, whereas fertigation at
the end of the irrigation cycle reduced the potential for NO3 leaching. Long fertigation times
resulted in uniform NO3 distributions in the wetted regions for three of the four irrigation
systems. Surface-applied irrigation on finer-textured soils enhanced lateral spreading of water
and nitrates with subsequent infiltration downwards and horizontal spreading of soil NO3 near
the soil surface. Leaching potential increased with the difference between the extent of the
wetted soil volume and rooting zone.
Soil injection of swine manure on soybeans in Illinois compared with surface application resulted
in runoff concentration decreases of 93, 82, and 94 percent, and load decreases of 99, 94, and
99 percent for dissolved P, TP and algal-available P, respectively (Daverede et al. 2004).
Incorporating inorganic P fertilizer also reduced P concentration in runoff significantly. Runoff P
concentration and load from incorporated amendments did not differ from the control.
Allen and Mallarino (2008) assessed total runoff P, bioavailable P, and dissolved P
concentrations and loads in surface runoff after liquid swine manure application with or without
incorporation into soil and different timing of rainfall in Illinois. For events 24 hours after
application, P concentrations were two to five times higher for unincorporated manure than for
incorporated manure; P loads were 3.8 to 7.7, and 3.6 times higher. A 10- to 16-day rainfall
delay resulted in P concentrations that were about three times lower than for 24-hour events
across all unincorporated P rates.
Andraski et al. (2003) investigated the effects of manure history and tillage on P levels in runoff
from continuous corn in Wisconsin. Soil P levels increased with the frequency of manure
applications and P stratification was greater near the surface in no-till than in chisel plow. In
chisel plow, soil test P level was linearly related to dissolved P and bioavailable P loads in
runoff. In no-till, P loads were reduced by an average of 57 percent for dissolved P, 70 percent
for bioavailable P, and 91 percent for TP compared with chisel plow.
In an Iowa plot study, Bakhsh et al. (2009) determined the effects of swine manure application
to corn and soybeans on NO3-N concentrations in subsurface drainage water and corn-soybean
yields. Average flow-weighted NO3-N concentrations and leaching losses increased by greater
than 50 percent when manure was applied to both corn and soybean compared to manure
application to corn only, while yield differences were less than 4 percent. Those results suggest
that fall manure application to both corn and soybean is likely to increase NO3-N leaching to
shallow groundwater without resulting in significant yield benefits.
Chapter 2. Agriculture 2-71
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
Kleinman et al. (2009) evaluated losses of P in subsurface and surface flow as a function of
dairy manure application to no-till soils in Pennsylvania. Incorporation of manure by tillage
lowered P loss in leachate relative to broadcast application because of the destruction of
preferential flow pathways. In contrast, rainfall simulations on runoff plots showed that TP losses
in surface runoff differed significantly by soil but not by application method. Results confirm the
near-term benefits of incorporating manure by tillage to protect groundwater quality but suggest
that for surface water quality, avoiding soils prone to runoff is more important.
Warren et al. (2008) compared surface broadcast litter application and subsurface litter banding
on grassland in Alabama. Subsurface band applications resulted in forage yields equivalent to
those achieved by conventional broadcast litter applications and did not significantly alter the
Mehlich 3 extractable P content of soils collected at a depth of 0 to 15 cm.
In Arkansas, Pote et al. (2003) determined the effects of poultry litter incorporation into Bermuda
grass and mixed forage plots on quantity and quality of runoff water. Nutrient concentrations
and mass losses in runoff from incorporated litter were 80-95 percent less than in runoff from
surface-applied litter. Litter-incorporated soils had greater rain infiltration rates, water-holding
capacities, and sediment retention than soils receiving surface-applied litter. In a subsequent
study, Pote et al. (2009) confirmed that fully mechanized litter subsurface banding increased
forage yield while decreasing nutrient N and P loss in runoff by at least 90 percent compared to
surface-broadcast litter.
Sistani et al. (2009) evaluated the effect of broiler litter application method and the runoff timing
on nutrient and E. coli losses from Alabama perennial grassland. TP, inorganic N, and E. coli
concentrations in runoff from broadcast litter application were all significantly greater than from
subsurface litter banding. TP losses from broadcast litter applications averaged 6.8 times
greater than those from subsurface litter applications. Average NO3-N and TSS losses from
subsurface banding were reduced by 64 percent and 68 percent, respectively, compared to the
broadcast method.
In soil columns, Quo et al. (2009) evaluated nutrient release dynamics of Delmarva poultry litter
under local weather conditions. Release of most nutrients occurred principally in the first
100 days, but for P, release would last for years. The nutrient supply capacity of surface-applied
Delmarva poultry litter was predicted at 10.9 kg N/Mg (kilograms per megagram) and 6.5 kg
P/Mg. The results suggest that Delmarva poultry litter should be applied to conservation tillage
systems at 6.6 Mg/ha, which would furnish 25 kg P/ha and 63 kg N/ha to seasonal crops. In
repeated annual applications, the rate should be reduced to 5.2 Mg/ha, with supplemental N
fertilization to meet crop N requirements.
2-72 Chapter 2. Agriculture
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
Table 2-14. Summary of reported practice effects resulting from management of nutrient
application methods and timing
Location
New York
New York
Ontario
Ontario
Illinois
Kansas
Quebec,
Canada
Study
type
Soil
\J\Jll
column,
fipld
1 1 t?IU
Field
Plots
Field
Field
Plots
Fields
1 ItxIUO
Practice
Manure
incorporation
Cessation of
winter
manure
spreading
Nutrient
source and
timing
Sidedress N
application
Sidedress N
application
IWI Q n 1 1 rp
IVIdl 1 U 1 G
placement
rlpnth
ucpu i
Irrigation of
dairy effluent
Practice effects
Plowing-in manure apparently disturbs
macropores and promotes matrix flow, resulting in
greatly reduced P concentrations in tile drainage
effluent.
Significant decreases in winter concentrations of
TP, soluble P, TKN, and NO3-N but not TSS
following cessation of winter dairy manure
application to cropland.
Higher NO3-N concentrations observed in plots
where N sources applied shortly before soil
sampling. Trends of residual NO3-N concentrations
varied among experiments, and results were
inconclusive. Two-fold higher P concentrations
were observed in the manured plots than in the
inorganically fertilized plots as a result of higher
P2O5 inputs from swine manure.
For each kg N applied, 70-77 kg ha-1 of yield was
produced for Sidedress compared to 46-66 kg of
yield for preplant N application. When the same
amount of fertilizer was applied, significantly
greater yield (7.6%-10.6%) was produced with
Sidedress than preplant N application.
Of nine different N sources tested, the Sidedress
injection of N provided the highest corn yields (164
bu/a) and best N use efficiencies (0.96 Ib N/bu) at
locations receiving > 12 inches rainfall over the 15
week period after fertilizer application.
Deep manure injection treatments had 31-59
more kg N/ha than the shallow injection treatment
12-30 months after application. Higher corn yield
in the deep injected treatment attributed to
increased N use efficiency. Higher inorganic N
amounts in deep injection treatment attributed to
reduced N losses through ammonia volatilization,
leaching, ordenitrification
Seepage losses represented < 1% of the total
volume of effluents, nutrients and bacteria applied
implying a treatment efficiency of >99% compared
to conventional land spreading.
Source
Geohring et
al. 2001
Lewis and
Makarewicz
2009
^\j\j\j
Chen and
Samson
2002
Ma 2007
Ebelharet
al. 2009
Reiman et
al. 2009
All et al.
2007
Chapter 2. Agriculture
2-73
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
Table 2-14. Summary of reported practice effects resulting from management of nutrient
application methods and timing (continued)
Location
Ontario,
Canada
Spain
India
California
Illinois
Iowa
Study
type
Plot
Plot
Field
Modeling
Plots
Plot
Practice
Liquid
manure
injection
Waste
irrigation
Fertigation
Fertigation
Manure
injection
Manure
incorporation
Practice effects
Apparent recovery of manure TN was greater with
injection (59%) than topdress (41%) and transport
of N to ground- and surface waters was minimized
when side dressed at or below rates for optimal
yield. When injected N exceeded crop demand,
NO3-N increased to over 10 mg/kg in topsoil,
20 mg/L in drainage water, and to excessive
(3.6 g/kg) levels in stalks
Drainage NO3-N concentration and load increased
linearly by 0.69 mg NO3-N/L and 4.6 kg NO3-N/ha,
respectively, for each 10 kg N/ha applied over the
minimum of 275 kg N/ha. An increase in irrigation
efficiency did not induce a significant increase of
leachate concentration and the amount of NO3
leached decreased about 65%.
Water-soluble fertilizer (WSF) fertigation recorded
significantly higher total dry matter (1 81 .9 g) and
leaf area index (3.69) over the drip irrigation
control. Fertigation with 100% WSF increased the
fruit yield by 24.8% over the furrow- irrigated
control and by 9.2% over drip irrigation. WSF
fertigation resulted in significantly fertilizer-use
efficiency (226.48 kg yield/kg NPK) compared to
drip- and furrow- irrigated controls. Fertigation
resulted in less leaching of NO3-N and Kto deeper
layer of soil and subsurface drip fertigation caused
higher assimilable P in deeper layers. Root growth
and NPK uptake was increased by WSF
fertigation.
An adapted version of the computer simulation
model, Hydrus-2D was used to evaluate NO3
leaching potential under various combinations of
micro-irrigation systems, fertigation scenarios, and
soil types typical of California conditions. The
study concluded that fertigation at the beginning of
the irrigation cycle tends to increase seasonal NO3
leaching.
Soil injection of manure on soybeans compared
with surface application resulted in runoff P
concentration decreases of 82%-99%.
For events 24-hours after application, P
concentrations were 2 to 5 times higher for
unincorporated manure than for incorporated
manure; P loads were 3.8 to 7.7, and 3.6 times
higher.
Source
Coelho et al.
2006
Dauden et
al.2004
Hebbaret al.
2004
Cardenas et
al. 2005
Daverede et
al. 2004
Bakhsh et al.
2009
2-74
Chapter 2. Agriculture
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
Table 2-14. Summary of reported practice effects resulting from management of nutrient
application methods and timing (continued)
Location
Wisconsin
Iowa
Pennsyl-
\/Q n i a
VCII 1 ICI
Alabama
Arkansas
Alabama
Delmarva
Peninsula
Study
type
Field
Plot
Plots
Field
Plots
Plots
Plot
Practice
Manure
history,
tillage
IWI Q n 1 1 rp
IVIdl 1 U 1 G
application
timinn
in i MI ly
Manure
incorporation
by tillage
Subsurface
banding of
poultry litter
Litter
application
ratp
1 QIC/
Subsurface
banding of
poultry litter
Soil aeration
Practice effects
Soil P levels increased with the frequency of
manure applications. In no-till, P loads were
reduced by an average of 57% for dissolved P,
70% for bioavailable P, and 91% forTP compared
with chisel plow
NO3-N concentrations and leaching losses
increased by > 50% when manure applied to both
corn and soybean compared to manure application
to corn only, while yield differences were less than
4%. Fall manure application to both corn and
soybean is likely to increase NO3-N leaching to
shallow groundwater without resulting in significant
yield benefits.
Incorporating manure by tillage lowered P loss in
leachate relative to broadcast application from the
destruction of preferential flow pathways; TP
losses in surface runoff differed significantly by soil
but not by application method
Subsurface band applications resulted in forage
yields equivalent to conventional broadcast litter
applications and did not significantly alter the
Mehlich 3 extractable nutrient content of soils.
Nutrient concentrations and mass losses in runoff
from incorporated litter were 80%-95% less than
in runoff from surface-applied litter. Litter-
incorporated soils had greater infiltration rates,
water-holding capacities, and sediment retention
than soils receiving surface-applied litter
TP, inorganic N, and E. coli concentrations in
runoff from broadcast litter application exceeded
those from subsurface litter banding. TP losses
from broadcast litter applications averaged 6.8
times greater than those from subsurface litter
applications. Average NO3-N and TSS losses from
subsurface banding were reduced by 64% and
68%, respectively, compared to the broadcast
method.
Soil aeration reduced runoff volume by 27% in the
first runoff event but the effect disappeared after 1
month; aeration did not affect the mass losses of
DRP, TKN, or NH4-N from plots fertilized with
either inorganic fertilizer or poultry litter
Source
AnHracki pt
/^llUldOIVI GL
al 2003
Cll . ^\J\J\J
Bakhsh et al.
2009
Pote et al.
2009
^\j\j *j
Warren et al.
2008
Guo et al.
(2009
Kai^pr pt al
1 \CllOtxl GL Cll .
2009
^\J\J *J
Guo et al.
2006
Chapter 2. Agriculture
2-75
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
Table 2-14. Summary of reported practice effects resulting from management of nutrient
application methods and timing (continued)
Location
Iowa
Georgia
Georgia
Georgia
British
Columbia,
Canada
Study
type
Field
Plot
Field
Plots
Field
Practice
Soil aeration,
broiler litter
Soil aeration
Soil aeration
Soil aeration
Soil aeration
Practice effects
Unincorporated manure consistently increased
concentrations of all runoff P fractions in five sites;
on average manure increased dissolved P,
bioavailable P, and TP 32, 23, and 12 times,
respectively, over the control. Tillage to
incorporate manure reduced dissolved P,
bioavailable P, and TP by 88, 89, and 77% on
average
Soil aeration reduced runoff volume by 27% in the
first runoff event but the effect disappeared after
one month; aeration did not affect the mass losses
of DRP, TKN, or NH4-N from plots fertilized with
either inorganic fertilizer or poultry litter
On well-drained soils, grassland aeration reduced
surface runoff volume and mass losses of DRP in
runoff by 35%. However, on poorly drained soils,
grassland aeration increased runoff volume and
mass losses of dissolved and TP
Core aeration reduced TP export by 55%,
dissolved P by 61 %, and bioavailable P by 54%
plots with applied broiler litter. Core and no-till disk
aeration also showed potential for reducing P
export from applied dairy slurry.
For mechanically aerating grassland before liquid
manure application, annual runoff amounts were
reduced by 47%-81%, suspended and volatile
solid loads by 48%-69% and 42%-83%,
respectively, TKN loads by 56%-81%, and TP
loads by 25%-75%. Loads of the soluble nutrient
NH4-N, DRP, and K were reduced by 41%-83%.
Source
Kaiser et al.
2009
Butler et al.
2006
Franklin et
al. 2007
Butler et al.
2008a
van Vliet et
al. 2006
Kaiser et al. (2009) assessed P loss immediately after poultry manure application to soybean
residue with and without tillage at eight Iowa fields. Unincorporated manure consistently
increased concentrations of all runoff P fractions in five sites. On average, non-incorporated
manure increased dissolved P, bioavailable P, and TP 32, 23, and 12 times, respectively, over
the control. Tillage to incorporate manure reduced dissolved P, bioavailable P, and TP by 88,
89, and 77 percent on average, respectively.
In a Georgia plot study, Franklin et al. (2006) reported that soil aeration reduced runoff volume
by 27 percent in the first runoff event but the effect disappeared after one month; aeration did
2-76
Chapter 2. Agriculture
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
not affect the mass losses of dissolved reactive P (DRP), TKN, or NH4-N from plots fertilized
with either inorganic fertilizer or poultry litter.
Franklin et al. (2007) evaluated the effects of slit aeration on runoff volume and P losses from
fescue fertilized with broiler litter in Georgia. In the field with mostly well-drained soils, grassland
aeration reduced surface runoff volume and mass losses of DRP in runoff by 35 percent.
However, on poorly drained soils, grassland aeration increased runoff volume and mass losses
of dissolved and TP.
Butler et al. (2008a) evaluated the effects of three aeration treatments on export of TSS and P
from grassland plots receiving broiler litter and dairy slurry in Georgia. Core aeration reduced
export of TP by 55 percent, dissolved P by 61 percent, and bioavailable P 54 percent on plots
with applied broiler litter as compared with the control. Core and no-till disk aeration also
showed potential for reducing P export from applied dairy slurry.
In British Columbia, Canada, van Vliet et al. (2006) studied the effect of mechanically aerating
grassland before liquid manure application on surface runoff and transport of nutrients and
solids. Annual runoff amounts were reduced by 47-81 percent, suspended and volatile solid
loads by 48-69 percent and 42-83 percent, respectively, TKN loads by 56-81 percent, and TP
loads by 25-75 percent. Loads of the soluble nutrient NH4-N, DRP, and K were reduced by
41-83 percent.
So/7 and manure amendment
Implementation Measure A-11:
Use soil amendments such as alum, gypsum, or water treatment residuals (WTR) to
increase P adsorption capacity of soils, reduce desorption of water-soluble P, and
decrease P concentration in runoff.
Because runoff losses of P are strongly influenced by the quantity and form of P in the soil
(Sharpley 1995; Pote etal. 1996), reducing P runoff from cropland can be accomplished by
influencing soil test P levels through soil amendments that change the availability of P and
through NMP.
In Arkansas plots, Haustein et al. (2000) surface application of treatment residuals and HiClay11
Alumina to soil plots high in P decreased Mehlich 3 soil test P levels and the two highest rates
of WTR decreased runoff P levels below those of the control plots.
Chapter 2. Agriculture 2-77
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
From a Texas field experiment, Brauer et al. (2005) reported that annual additions of gypsum at
5.0 Mg/ha significantly reduced soil-dissolved P, although soil amendment did not affect Bray 1
P values. Elliott et al. (2002) conducted laboratory and greenhouse studies of the ability of WTR
to alter P solubility and leaching in a Texas soil amended with biosolids and triple
superphosphate. Without residual amendment, 21 percent of soluble P and 11 percent of
biosolids TP leached over 4 months. With co-applied residuals, soluble P losses were reduced
to less than 1-3.5 percent of applied P. Amendment with residuals retarded downward P flux
such that leachate P was not statistically different than for control (soil only) columns.
In North Carolina, Novak and Watts (2004) conducted laboratory experiments to determine if
WTR mixed into soils could significantly increase their P sorption capacities. Mixing residuals
into soils increased their P-max values several-fold (between 1.7 to 8.5 mg P/g) relative to soils
with no WTR addition. The authors suggested that WTR incorporation into sandy soils has the
potential to be a new chemical-based best management practice (BMP) for reducing off-site P
transport.
In Oklahoma, Peters and Basta (1996) reported that alum-based WTR applied at 30-100 g/kg
soil reduced Mehlich 3 extractable P in soils from 553 mg/kg to 250 mg/kg (55 percent) in one
soil and from 296 mg/kg to 110 mg/kg (63 percent) in another soil. Reductions of soluble P
followed similar trends. Treatments did not result in excessive soil pH or increase in soil salinity,
soil extractable Al, or heavy metals.
In a Maryland study, Codling et al. (2000) reported that addition of poultry litter amended with
alum-based WTR led to significant reductions in water soluble P concentrations in several soils.
The authors reported reductions in water-soluble P of 72-99 percent in soils amended with
10-50 g/ha treated poultry litter after 2 to 4 weeks. Reductions of 27-89 percent in Bray 1 P
were reported in the same soils.
Cornwell et al. (2000) reported a 34 percent reduction in available soil P after application of
alum WTR at a rate of 25.7 dry t/ha to Pennsylvania agricultural soils with soil P levels six times
higher than optimum level for soybean production.
Novak and Watts (2005) evaluated the ability of alum-based WTR to reduce soil P
concentrations in three P-enriched North Carolina Coastal Plain soils. Incorporating residuals
into the soils caused a near linear and significant reduction in soil P concentrations. In two soils,
6 percent WTR application caused a soil Mehlich 3 P concentration decrease to below the soil P
threshold.
Adding WTR to Oklahoma soil plots treated with poultry litter reduced runoff P by 14-85 percent
(Dayton et al. 2003). Reductions in runoff P were strongly correlated with P-max and Al-ox.
2-78 Chapter 2. Agriculture
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
Performance of treatment residuals as a P sorbent to reduce runoff P from manured land can be
estimated from their P-max or Al-ox content.
In a Connecticut laboratory study, Hyde and Morris (2000) reported that WTR significantly
reduced Mehlich 3 P concentrations when added to soils. Adding residuals to soils reduced soil
P concentrations by 23-64 percent, depending on how the residuals were dewatered.
Adler and Sibrell (2003) tested the use of flocculants (floes) resulting from neutralizing acid mine
drainage (AMD) (as a possible low-cost amendment to reduce the loss of soluble P from
agricultural fields and animal wastewater) in West Virginia. About 70 percent of WEP was
sequestered by the floe when applied to agricultural soils at a rate of 20 g floe/kg soil, whereas
plant-available P decreased by 30 percent. Under anaerobic conditions simulating manure
storage basins, all AMD floes reduced soluble P by greater than 95 percent.
At two Michigan field sites with a history of heavy manure applications, amendment with WTR
reduced water-soluble P concentration by greater than or equal to 60 percent as compared to
the control plots, and the residuals-immobilized P remained stable 7.5 years after residuals
application (Agyin-Birikorang et al. 2007).
Staats et al. (2004) investigated the efficacy of alum-amended poultry litter in reducing P
release from three Delaware Coastal Plain soils. Long-term desorption (25 days) of the
incubated material resulted in about 13 percent reductions in cumulative P desorbed when
comparing soil treated with unamended poultry litter. In addition, the P release from the soil
treated with alum-amended litter was not significantly different from the control (soil alone).
Zvomuya et al. (2006) tested the P-binding ability of various amendment materials in a
laboratory soil incubation experiment. Lysimeter breakthrough tests using tertiary-treated
potato-processing wastewater showed that alum application reduced leachate TP and SRP
concentrations by 27 percent and 25 percent, respectively.
Stout et al. (1999) reported that a 10 g/kg application of a gypsum byproduct to Pennsylvania
soils reduced the concentration of water-soluble P by 50 percent. Projection of these results
over an agricultural watershed indicated that treating only four percent of the watershed could
reduce the loss of water-soluble P by 30 percent. In an Indiana lab study, Favaretto et al. (2006)
showed that gypsum addition to soils significantly decreased the mass loss in runoff of dissolved
reactive P, TP, soluble NH4-N, and total N by 85, 60, 80, and 59 percent, respectively. The
concentration of these constituents was also significantly decreased by 83, 52, 79, and 50
percent, respectively. Murphy et al. (2010) reported that gypsum addition decreased reactive P
solubility by 14-56 percent and organic P solubility by 10-53 percent in five Irish soils.
Chapter 2. Agriculture 2-79
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
Table 2-15. Summary of reported practice effects resulting from soil and manure amendment
Location
Arkansas
Texas
Oklahoma
Maryland
Pennsyl-
vania
Texas
North
Carolina
North
Carolina
Oklahoma
Study type
Plot
Field
Field
Field
Field
Laboratory,
greenhouse
Laboratory
Laboratory
Plots
Practice
Soil
amendments
Gypsum
amendment
WTR
WTR
WTR
WTR
WTR
WTR
WTR
Practice effects
Surface application of treatment residuals and
HiClay® Alumina to high P soils decreased
soil test P levels; the highest rates of WTR
decreased runoff P levels below those of the
control plots.
Annual additions of gypsum at 5.0 Mg/ha
significantly reduced soil dissolved P,
although soil amendment did not affect Brayl
P values.
Alum-based WTRs applied at 30-100 g/kg
soil reduced Mehlich 3 extractable P in soils
from 55% to 63%.
Addition of poultry litter amended with alum-
based WTRs led to 72%-99% reductions in
water-soluble P and 27%-89% reductions in
Bray 1 P of in soils amended with 1 0-50 g/ha
treated poultry litter after 2 to 4 weeks.
34% reduction in available soil P after
application of alum WTRs at a rate of 25.7 dry
t/ha to soils with soil P levels six times higher
than optimum level for soybean production.
Without residual amendment, 21% of soluble
P and 1 1 % of biosolids TP leached over 4
months; with co-applied residuals, soluble P
losses were reduced to < 1%-3.5% of applied
P. Amendment with residuals retarded
downward P flux such that leachate P was not
statistically different than for control (soil only)
columns.
Mixing residuals into soils increased their P-
max values several-fold (between 1 .7 to 8.5
mg P/g) relative to soils with no WTR
addition.
Incorporation of residuals into soils caused a
near linear and significant reduction in soil P
concentrations. In two soils, 6% WTR
application caused a soil Mehlich 3 P
concentration decrease to below the soil P
threshold.
Addition of WTR to OK soil plots treated with
poultry litter reduced runoff P by from 14%-
85% Reductions in runoff P were strongly
correlated with P-max and Al-ox.
Performance of treatment residuals as a P
sorbent to reduce runoff P from manured land
can be estimated from their P-max or Al-ox
content.
Source
Haustein et al.
2000
Brauer et al.
2005
Peters and
Basta 1 996
Codling et al.
2000
Cornwell et al.
2000
Elliott et al.
2002
Novak and
Watts 2004
Novak and
Watts 2005
Dayton et al.
2003
2-80
Chapter 2. Agriculture
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
Table 2-15. Summary of reported practice effects resulting from soil and manure amendment
(continued)
Location
Connect-
icut
Pennsyl-
vania,
Oklahoma,
Colorado
West
Virginia
Michigan
Delaware
Various
Pennsyl-
vania
Indiana
Ireland
Study type
Laboratory
Field
Laboratory
Field
Laboratory
Laboratory
Laboratory
Laboratory
Laboratory
Practice
WTR
WTR
Neutralized
AMD floes
WTR
Alum
amendment
Alum soil
amendment
Gypsum
amendment
Gypsum
amendment
Gypsum
amendment
Practice effects
Adding residuals to soils reduced soil P
concentrations by 23%-64%, depending on
how the residuals were dewatered.
WTRs reduced Mehlich 3 soil test P to less
than 200 mg/kg at a 10% loading rate after 1
wk of incubation time. Reductions of soluble P
(CaCI2 extraction) were greater than
reductions in Mehlich 3 P.
About 70% of WEP was sequestered by the
floe when applied to agricultural soils at a rate
of 20 g floe/kg soil; plant-available P
decreased by 30%. Under anaerobic
conditions simulating manure storage basins,
AMD floes reduced soluble P by > 95%.
Amendment reduced water-soluble P
concentration by > 60% vs. control plots, and
the residuals-immobilized P remained stable
for 7. 5 yr.
About 13% reductions in cumulative P
desorbed vs. soil treated with unamended
poultry litter. P release from soil treated with
alum-amended litter was not significantly
different from the control (soil alone).
Lysimeter breakthrough tests showed that
alum application reduced leachate TP and
SRP concentrations by 27% and 25%,
respectively
10 g/kg application of a gypsum byproduct to
Pennsylvania soils reduced the concentration
of water-soluble P by 50%.
Gypsum addition to soils significantly
decreased the mass loss in runoff of
dissolved reactive P (85%), TP (60%), soluble
NH4-N (80%), and total N (59%).
Gypsum addition decreased reactive P
solubility by 14%-56% and organic P
solubility by 10%-53%.
Source
Hyde and
Morris 2000
DeWolfe 2006
Adlerand
Sibrell 2003
Agyin-
Birikorang et
al. 2007
Staats et al.
(2004)
Zvomuya et
al. 2006
Stout et al.
1999
Favaretto et
al. 2006
Murphy et al.
2010
Nutrient management planning
In a Virginia field study, Maguire et al. (2008) investigated how changing poultry litter application
rates from an N to a P basis affected crop yields and soil properties in high P soils over a 7-year
period. After 7 years, Mehlich 1 P and water-soluble P were greatest in soils under the N-based
Chapter 2. Agriculture
2-81
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
treatments, smallest in the no-P treatment, and intermediate in the P-based treatments; there
were no significant differences between inorganic fertilizer and poultry litter nutrient sources.
The results show that soil test P can be decreased in high-P soils over a few years by changing
from an N-based to a P-based nutrient management plan or by stopping P applications without
negatively affecting yields.
In Quebec, Canada, Giroux and Royer (2007) measured the effect of three P fertilizer rates on
crop yields and evolution of the soil test values, saturation and P solubility. Soil test P values
decreased by 11-33 percent over 8 years, even at P application rates above crop removal
rates. Annual rates of P-sat decrease were 1.087, 0.891 and 0.750 percent/year respectively for
the 0, 30, and 60 kg P2O5/ha fertilizer rates. The P-sat value of 13.1 percent of the Quebec
regulation was achieved after 10 years for the 0 kg P2O5/ha rate.
Table 2-16. Summary of reported practice effects resulting from nutrient application planning
Location
Virginia
Quebec,
Canada
Texas
Texas
Texas
Study
type
Field
Field
Field
Plot
Model
Practice
P-based
nutrient
management
P fertilizer
rates
Turfgrass sod
export
Zero P fertilizer
P-based
manure
management
Practice effects
After? years, Mehlich 1 P and water soluble P
were greatest in soils under the N-based
treatments, smallest in the no P treatment, and
intermediate in the P-based treatments. Soil test P
can be decreased in high-P soils by changing from
an N-based to a P-based nutrient management
plan or stopping P applications without negatively
affecting yields.
Soil test P values decreased by 11%-33% over 8
years, even at P application rates above crop
removal. Annual rates of P-sat decrease were
1.087, 0.891 and 0.750%/yr, respectively, for the
0, 30, and 60 kg P2O5/ha fertilizer rates. The P-sat
value of 13.1% of the Quebec regulation is
achieved after 10 years for the 0 kg P2O5/ha rate
46%-77% of the applied manure P removed in a
single turfgrass sod harvest. Total dissolved P
concentrations in the runoff were directly related to
P concentrations in the soil. 3.8% of the applied P
from composted dairy manure was lost in the
surface runoff.
Using only commercial N on soils with high
extractable P levels decreased P loadings in edge-
of-field runoff by > 40%.
Edge-of-field TP losses can be reduced by about
0.8 kg/ha/year or 14% when manure applications
are calibrated to supply all the recommended crop
P requirements from manure TP sources only, vs
manure applications at N agronomic rate.
Source
Maguire et
al. 2008
Giroux and
Royer 2007
Choi et al.
2003
McFarland
and Hauck
2004
Osei et al.
2008
2-82
Chapter 2. Agriculture
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
In Texas, Choi et al. (2003) reported that 46-77 percent of the applied manure P was removed
in a single turfgrass sod harvest. Total dissolved P concentrations in the runoff were directly
related to P concentrations in the soil. A total of 3.8 percent of the applied P from composted
dairy manure was lost in the surface runoff.
From Texas plot studies, McFarland and Hauck (2004) reported that using only commercial N
on soils with high extractable P levels decreased P loadings in edge-of-field runoff by greater
than or equal to 40 percent. However, no notable changes in extractable soil P concentrations
were observed after 5 years of monitoring because of drought conditions limiting forage uptake
and removal.
In a Texas study using an integrated economic and environmental modeling system across
multiple ecoregions, Osei et al. (2008) suggested that edge-of-field TP losses can be reduced
by about 0.8 kg/ha/year or 14 percent when manure applications are calibrated to supply all the
recommended crop P requirements from manure TP sources only, when compared to manure
applications at the recommended crop N agronomic rate.
3.2 Sediment and Erosion Control
Sediment loss is the result of erosion. It is the solid material, both mineral and organic, that is in
suspension, is being transported, or has been moved from its site of origin by wind, water,
gravity, or ice. The types of erosion associated with agriculture that produce sediment are
(1) sheet and rill erosion, (2) ephemeral and classic gully erosion, (3) wind erosion, and
(4) streambank erosion. Soil erosion can be characterized as the transport of particles that are
detached by rainfall, flowing water, or wind. Eroded soil is either redeposited on the same field
or transported from the field in runoff or by wind.
The strategies for controlling erosion and sedimentation involve reducing soil detachment,
reducing sediment transport, and trapping sediment before it reaches water. The first objective
for both water and wind erosion is to keep soil on the field, and the easiest and often most
effective strategy to accomplish that is to reduce soil detachment. Detachment occurs when
water splashes onto the soil surface and dislodges soil particles or when wind reaches sufficient
velocity to dislodge soil particles on the surface.
Crop residues (e.g., straw) or living vegetative cover (e.g., cover crops, grasses) on the soil
surface protect against detachment by intercepting and/or dissipating the energy of falling
raindrops. A layer of plant material also creates a thick layer of still air next to the soil to buffer
against wind erosion. In some areas, crops that maintain a greater surface coverage could be
substituted for existing crops to control erosion.
Chapter 2. Agriculture 2-83
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
Implementing tillage practices such as continuous no-till or other forms of conservation tillage
also preserves or increases organic matter and soil structure, resulting in improved water
infiltration and surface stability. In addition, creating a rough soil surface through practices such
as surface roughening will break the force of raindrops and trap water, reducing runoff velocity
and erosive forces.
Sediment transport can be reduced in several ways, including using crop residues or
conservation buffers. Vegetation slows runoff, increases infiltration and traps sediment.
Reductions in slope length and steepness reduce runoff velocity, thereby reducing sediment
carrying capacity as well. Practices are also typically needed to trap sediment leaving the field
before it reaches a wetland or riparian area. Deposition of sediment is achieved by practices
that slow water velocity or increase infiltration.
Properly functioning natural wetlands and riparian areas can significantly reduce nonpoint
source pollution by intercepting surface runoff and subsurface flow and by settling, filtering, or
storing sediment and associated pollutants. Wetlands and riparian areas typically occur as
natural buffers between uplands and adjacent waterbodies. Loss of these systems allows a
more direct contribution of nonpoint source pollutants to receiving waters. Degraded wetlands
and riparian areas can even become pollutant sources. Thus, natural wetlands and riparian
areas should be protected and should not be used as designated erosion control practices.
Their nonpoint source control functions are most effective as part of an integrated land
management system focusing on nutrient, sediment, and erosion control practices applied to
upland areas.
Additional descriptions of erosion and sediment control practices are in previous guidance
(USEPA 2003). Also, NRCS provides a host of Practice Codes that can be used to implement
sediment and erosion controls.
Implementation Measure A-12:
Use conservation tillage or continuous no-till on cropland to reduce soil erosion and
sediment loads except on those lands that have no erosion or sediment loss.
Conservation tillage includes a variety of tillage systems that leave varying amounts of residue
on a field. Continuous no-till leaves all residue after harvest on the field, protecting the soil. In
general, conservation tillage is any tillage system that maintains 30 percent or more of the soil
surface with crop residue after planting (USDA-NRCS 201 Od). The amount of residue needed to
achieve erosion and sediment reduction goals, however, is dependent on numerous factors; the
2-84 Chapter 2. Agriculture
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
Revised Universal Soil Loss Equation (RUSLE) is a tool that can help determine the amount left
on the field.
Water erosion rates are affected by rainfall energy, soil properties, slope, slope length,
vegetative and residue cover, and land management practices. Rainfall impacts provide the
energy that causes initial detachment of soil particles. Soil properties like particle size
distribution, texture, and composition influence the susceptibility of soil particles to be moved by
flowing water. Vegetative cover and residue can protect the soil surface from rainfall impact or
the force of moving water. Those factors are used in the RUSLE, an empirical formula widely
used to predict soil loss in sheet and rill erosion from agricultural fields, primarily crop land and
pasture, and construction sites (USDA-ARS 2005):
Revised Universal Soil Loss Equation (RUSLE)
where
A = estimated average annual soil loss (tons/acre/year)
R = rainfall/runoff factor, quantifying the effect of raindrop impact and the amount and rate of
runoff associated with the rain, based on long-term rainfall record
K= soil erodibility factor based on the combined effects of soil properties influencing erosion
rates
LS = slope length factor, a combination of slope gradient and continuous extent
C = cover and management factor, incorporating influences of crop sequence, residue
management, and tillage
P= practice factor, incorporating influences of conservation practices such as contouring or
terraces
Practice Effectiveness
Past reviews of the effectiveness of sediment control measures have concluded that reduced
tillage systems reduce TP losses by 45 percent, TN losses by 55 percent, and sediment losses
by 75 percent (USEPA 2003).
Harmel et al. (2006, 2008) have compiled measured annual N and P load data representing
field scale transport from agricultural land uses. The 2006 compilation includes results from
40 scientifically peer-reviewed studies but draws heavily from the 1980s. The more recent data
(2008 update) include 15 additional studies. In all, the database contains 1,677 watershed years
of data for various agricultural land uses and practices. Most data are from the Southeast and
Chapter 2. Agriculture 2-85
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
upper Midwest, with only one study from the Chesapeake Bay Drainage area. Table 2-17,
below, provides a summary of median N and P export coeffcients from Harmel et al. (2006) from
which N and P reductions could be estimated. The current version is at
http://www.ars.usda.gov/spa/manage-nutrient.
Table 2-17. Median N and P export coefficients
Table 4. Median annual dissolved, particulate, and TN and P export coefficient
selected treatments
Treatment*
Tillage
Conventional
Conservation
No-Till
Pasture/Range
Conservation Practice
None
One Practice
2+ Practices
Soil Texture
Clay
Loam
Sand
TN
(kg/ha)
7.88a
7.70a
1.32b
0.97b
2.19a
6.73b
8.72b
4.93a
4.05a
2.74a
Dissolved N
(kg/ha)
2.41a
2.30ac
4.20c
0.32b
1.60a
1.33a
2.61b
4.47a
1.64b
1.70ab
Particulate N
(kg/ha)
7.04a
3.40c
1.80bc
0.62b
1.70a
14.80a
3.30a
2.00a
5.78b
**
TP
(kg/ha)
1.05a
1.18ac
0.63c
0.22b
0.41a
0.61 ab
1.22b
0.92a
0.41b
1.50ab
values (kg/ha) for
Dissolved P
(kg/ha)
0.19b
0.65ac
1.00c
0.15b
0.26ab
0.14a
O.SOb
O.SOa
0.18b
0.07ab
Particulate P
(kg/ha)
0.64a
1.00a
O.SOa
O.OOb
0.64ab
0.37a
0.75b
0.55a
0.93a
**
Source: Harmel et al. 2006
* For each nutrient form within a treatment, medians followed by a different letter are significantly different (a - 0.05).
** No particulate N or P data were available for sandy soils.
In another literature review, Merriman et al. (2009) developed a compilation of BMP
effectiveness results. Table 2-18 presents a listing of individual results for conservation tillage
practices along with percent reductions for TP, TN, and sediment. Additional data on reductions
for particulate P, dissolved P, NO3-N, and ammonium are also available.
Soil loss and ortho-P transport were measured from a conventional and two conservation tillage
treatments (zero and ridge tillage) from January 1988 to September 1990 in southwestern
Ontario (Gaynor and Findlay 1995). Compared to conventional tillage, conservation tillage
reduced average soil loss by 49 percent (899 kg/ha) and increased ortho-P concentrations in
runoff 2.2 times (0.25 mg/L).
2-86
Chapter 2. Agriculture
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
Table 2-18. TP, TN, and sediment reductions for various conservation tillage practices
Reference
(as cited by
Merriman et al.
2009)
Zhuetal. 1989
Zhuetal. 1989
Zhuetal. 1989
Dabney et al.
1993
Dabney et al.
1979
Dabney et al.
1979
Dabney et al.
1993
Yooetal. 1988
Mutchler et al.
1985
Meyer et al. 1999
McGregor and
Greer 1982
Yooetal. 1986
Meyer et al. 1999
Meyer et al. 1999
Hairston et al.
1984
McGregor et al.
1975
McGregor et al.
1975
Mutchler and
Greer 1984
Hairston et al.
1984
Langdale et al.
1979
Truman et al.
1979
Dabney et al.
1993
Dabney et al.
1993
Dabney et al.
1993
State
Missouri
Georgia
Georgia
Mississippi
Georgia
Georgia
Mississippi
Alabama
Mississippi
Mississippi
Virginia
Alabama
Virginia
Louisiana
Virginia
Virginia
Mississippi
Mississippi
Mississippi
Georgia
Georgia
Mississippi
Mississippi
Mississippi
BMP name
No-till
No-till
No-till
No-till
No-till
No-till
No-till
No-till
No-till
No-till
No-till
No-till
No-till
No-till
No-till
No-till
No-till
No-till
No-till
No-till
No-till
No-till
No-till
No-till
Study scale
Field plot
Field plot
Field plot
Field plot
Field plot
Field plot
Field
Field plot
Field plot
Field plot
Field plot
Field plot
Field plot
Field plot
Field plot
Field plot
Field plot
Field plot
Field plot
Field plot
Field plot
Field plot
Field plot
Field plot
3-8
3
3
3
3-8
3
3
3-8
3-8
3-8
3-8
8
8
8
3-8
3-8
8
3-8
3-8
3-8
3-8
3-8
3-8
3-8
3-8
C
D
D
D
C
B
C
B
B
C
C
C
B
C
C
D
B
C
C
C
B
C
C
C
C
5%
84%
TN%
7.6%
90%
-2.76%
Total
sediment
%
92%
90%
92%
72.3%
86%
86%
95.49%
20.8%
47%
99%
95.49%
54.44%
85.11%
90.84%
16.28%
85.71%
85.71%
94.08%
92.7%
86%
86%
56.76%
50%
66.67%
Chapter 2. Agriculture
2-87
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
Table 2-18. TP, TN, and sediment reductions for various conservation tillage practices (continued)
Reference
(as cited by
Merriman et al.
2009)
Dabney et al.
1993
Yooetal. 1988
Schreiber and
Cullum 1998
Meyer et al. 1999
Mostaghimi,
Dillaha,
Shanholtz1988
Mostaghimi et al.
1992
Mostaghimi et al.
1991
Feagley et al.
1992
Daniels and
Gilliam 1996
Mostaghimi et al.
1991
McGregor and
Greer 1982
McGregor and
Greer 1982
Hairston et al.
1984
Mutchler and
Greer 1984
Truman et al.
2003
State
Mississippi
Alabama
Mississippi
Mississippi
Virginia
Virginia
Virginia
Louisiana
Virginia
Virginia
Mississippi
Mississippi
Mississippi
Mississippi
Alabama
BMP name
No-till
No-till
No-till
No-till
No-till
No-till
No-till
No-till
No-till with
subsurface
injection
No-till with
subsurface
injection
Reduced
Tillage
Reduced
Tillage
Reduced
Tillage
Reduced
Tillage
Cover crop
(general)
Study scale
Field plot
Field plot
Large watershed
Field plot
Field plot
Field plot
Field plot
Field plot
Field plot
Field plot
Field plot
Field plot
Field plot
Field plot
Field plot
3-8
3-8
3-8
3-8
3-8
8-15
8-15
8-15
N/A
3-8
8-15
3-8
3-8
3-8
3-8
N/A
C
c
B
C
C
C
C
C
D
B
C
C
B
D
C
B
22.5%
76.52%
97%
65.52%
91%
TN%
23.8%
67.68%
90.55%
90.55%
95.42%
Total
sediment
%
83.33%
52.3%
88.47%
98%
69.47%
94.75%
74.25%
92%
91.84%
91.84%
13.85%
58.78%
46%
Source: Merriman etal. 2009
Using a rain simulator on plots, Avalos et al. (2007) found that corn straw residue decreased N
losses from 88.82 to 16.65 kg/ha (81 percent reduction) and decreased TP losses from 7.87 to
1.72 kg/ha (78 percent reduction). In another plot study using rainfall simulation, it was found
that under no-till conditions, plots with corn residue and grass hedges averaged 52 percent less
runoff and 53 percent less soil loss than similar plots without grass hedges (Gilley et al. 2000).
Under tilled conditions, the plots with corn residue and grass hedges averaged 22 percent less
runoff and 57 percent less soil loss than comparable plots without grass hedges. The plots with
2-88
Chapter 2. Agriculture
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
corn residue removed but with grass hedges present averaged 41 percent less runoff and
63 percent less soil loss than similar plots without grass hedges.
One alternative to reduce compaction and restricted infiltration under long periods of no-till is
rotational tillage (Smith et al. 2007). In the first year of converting from long-term, no-till to
rotational tillage on small plots that had been in a no-till corn-soybean rotation for 15 years,
runoff volumes and nutrient concentrations for NH4-N, NO3-N, and dissolved P (DP) were
greater from the no-till field. Before fertilization, no-till resulted in 83 g/ha greater NH4-N and
32.4 g/ha greater dissolved P losses than rotational tillage. After fertilization, no-till was
observed to lose 5.3 kg/ha more NH4-N, 1.3 kg/ha more NO3-N, and 2.4 kg/ha more dissolved P
than rotational tillage.
Conventional tillage, conservation tillage with cover crop, and no-till with cover crop were
compared in a small grain-corn rotation in Austria in a field study from 1994 to 1999 (Klik et al.
2001). The field plots ranged from 3-4 m in width and 15-m long, and slope ranged from 6 to 16
percent. Runoff was not statistically different among the practices, but nutrient losses from April
to October were 13.7 kg/ha for conventional tillage, 9.1 kg/ha (34 percent decrease) for
conservation tillage, and 7.7 kg/ha (44 percent decrease) for no-till. P losses were 6.5, 3.1
(52 percent decrease), and 2.0 kg/ha (69 percent decrease), respectively. In a 9-year field study
in Finland, Puustinen etal. (2005) found that traditional cultivation treatments produced the
highest TSS concentrations (1.38 and 1.18 mg/L, respectively), whereas values between
0.44 and 0.53 mg/L were measured for three treatments with reduced (or no) tillage. Particle-
bound P concentrations closely followed those of TSS, but DRP showed contrasting behavior.
Finnish researchers (Turtola et al. 2007) found that the frequency of tillage, rather than the
depth of tillage, has a greater effect on erosion on clayey soils. Shallow autumn tillage produced
erosion as high as moldboard plowing (407-1700 kg/ha-yr), but 48 percent and 12 percent
lower erosion levels were measured from plots left untilled in autumn, covered by grass or
barley residues, respectively. In a companion study, Uusitalo et al. (2007) found that stubble
treatment yielded higher DRP losses (104-259 g/ha-yr) than autumn plowing (77-96 g/ha-yr),
and equally high particulate P (PP) losses (mean 660, 235-1,300 g/ha-yr). Shallow autumn
tillage produced 28 percent higher DRP losses (mean 120, 107-136 g/ha-yr) than plowing
(83-117 g/ha-yr) and 11 percent higher PP losses (mean 1,090, 686-1,336 g/ha-yr) than
plowing (783-1253 g/ha-yr).
Practice Costs
In an analysis of various combinations of practices to control sediment loss in a 12-ha
subwatershed of the Mississippi Delta Management System Evaluation Area using the
Annualized Agricultural Nonpoint Source pollutant loading model (AnnAGNPS 2.1), it was found
Chapter 2. Agriculture 2-89
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
that the most cost-effective practices were management of volunteer winter weeds as cover
crops and various types of edge-of-field, grade-control pipes (Yuan et al. 2002; Dabney et al.
2001). The average marginal cost using practices for sediment yield reduction was about
$10/MT (2010 dollars) for conventional and reduced tillage. The cost was higher, about $13/MT
for no-till because the practice of no-till alone reduced sediment yield by half, and further
marginal reductions were more expensive.
Using the Water Erosion Prediction Project, or WEPP, model calibrated to a 6.4-ha site within
Four Mile Creek watershed in eastern Iowa, Zhou et al. (2009) compared the cost of lost soil for
chisel plow, disk tillage, and no-tillage. The value of lost soil resulting from soil erosion ranged
between $11 and $139/ha-yr (2010 dollars) for the simulated scenarios in the study when a soil
value of $6.19/t was considered. When factoring in the value of soil, no-tillage was the most
efficient practice with the highest net benefit of $95.86/ha-yr.
Both national and selected state costs for a number of common erosion control practices are
presented in Table 2-19. The variability in costs for practices can be accounted for primarily
through differences in site-specific applications and costs, differences in the reporting units
used, and differences in the interpretation of reporting units. For example, grassed waterways in
Virginia cost $3,237/ac and terraces cost $0.59/ft with typical total costs of $2,972 and $295,
respectively (USDA-NRCS 2010).
Table 2-19. Representative costs of selected erosion control practices
Practice
Diversions
Terraces
Waterways
Permanent
Vegetative Cover
Conservation
Tillage
Unit
ft
ft
a.s.b
ft
ac
a.e.c
ac
ac
Range of capital
costs3
$2.63-$7.36
$4.43-$19.75
$32.24-$89.15
$7.85-$11.84
$151 -$5684
$1669-$2902
$92-$360
$12.68-$84.58
References
Sanders et al. 1991
Smolen and Humenik 1989
Smolen and Humenik 1989
Russell and Christiansen 1984
Sanders et al. 1991
Barbarika 1987; NCAES 1982; Smolen and
Humenik 1989
Russell and Christiansen 1984
Barbarika 1987; Russell and Christiansen 1984;
Sanders et al. 1 991 ; Smolen and Humenik 1 989
NCAES 1982; Russell and Christiansen 1984;
Smolen and Humenik 1989
Notes:
a. Reported costs inflated to 1998 dollars by the ratio of indices of prices paid by farmers for all production items, 1991 =
100. 1998 dollars then converted to 2010 dollars.
b. acre served
c. acre established
[Note: 1991 dollars from CZARA were adjusted by +15%, based on ratio of 1998 Prices Paid by Farmers/1991 Prices Paid
by Farmers, according to USDA National Agricultural Statistics Service, http://www.usda.gov/nass/sources.htm, 28
September 1998]. 1998 dollars then converted to 2010 dollars.
2-90
Chapter 2. Agriculture
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
The cost estimates for control of erosion and sediment transport from agricultural lands in Table
2-20 are based on experiences in the Chesapeake Bay Program.
Table 2-20. Annualized cost estimates and life spans for selected management practices from
Chesapeake Bay installations3
Practice
Nutrient Management
Strip-cropping
Terraces
Diversions
Sediment Retention Water Control Structures
Grassed Filter Strips
Cover Crops
Permanent Vegetative Cover on Critical Areas
Conservation Tillage01
Reforestation of Crop and Pastured
Grassed Waterways6
Animal Waste Systemf
Practice life span
3
5
10
10
10
5
1
5
1
10
10
10
Median annual costs'3
(Years) (EAC°)
($/acre/yr)
4.00
19.32
140.75
86.74
148.56
12.17
16.65
117.72
28.87
77.69
1 .67/LF/yr
6.26/ton/yr
Source: Camacho 1991
Notes:
a. Median costs (1990 dollars) obtained from the Chesapeake Bay Program Office (CBPO) BMP tracking data base
and Chesapeake Bay Agreement Jurisdictions' unit data cost. Costs per acre are for acres benefited by the practice.
1990 dollars converted to 2010 dollars.
b. Annualized BMP total cost including O&M, planning, and technical assistance costs.
c. EAC = equivalent annual cost: annualized total; costs for the life span. Interest rate = 10%.
d. Government incentive costs.
e. Annualized unit cost per linear foot of constructed waterway.
f. Units for animal waste are given as $/ton of manure treated.
Practice Savings
It is important to note that for some practices, such as conservation tillage, the net costs often
approach zero and in some cases can be negative because of the savings in labor and energy.
In fact, it is reported that cotton growers can lower their cost per acre by $88/ha (2010 dollars)
because of lower fixed costs associated with conservation tillage (Zeneca 1994).
Chapter 2. Agriculture
2-91
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
3.3 Cover Crops
Implementation Measure A-13:
Use the most suitable cover crops to scavenge excess nutrients and prevent erosion at
the site on acres that have received any manure or chemical fertilizer application.
Cover crops should be used during a non-growing season (including winters) or
when there is bare soil in a field.
A cover crop is any crop grown to provide soil cover, primarily to prevent soil erosion by wind
and water (Sullivan 2003) (NRCS Practice Code 340). Cover crops can be annual, biennial, or
perennial plants grown in a pure or mixed stand during all or part of the year to provide ground
cover, fix N (legumes), suppress weeds, reduce insect pests and diseases, and reduce nutrient
leaching following a main crop. The Midwest Cover Crop Council Web site
(www.mccc.msu.edu/CCinfo/cropbycrop.html) provides information on a variety of options for
planting cover crops, and describes the various plant species available. Cover crops come in
several forms, depending on the situation and objectives.
A winter cover crop is planted in late summer or fall to provide soil cover during the winter; a
legume is often planted to generate N for the subsequent crop (Sullivan 2003). Legumes,
however, are not recommended for reducing NO3 leaching. In general, a winter cover crop is
planted shortly before or soon after the main crop is harvested and remains on the field through
the winter. It is then killed or removed before or soon after planting of the subsequent season's
main crop.
A summer green manure is a warm-season cover crop used to fill a niche in crop rotations, to
improve the conditions of poor soils, or to prepare land for a perennial crop (Sullivan 2003).
Legumes such as cowpeas, soybeans, annual sweet clover, sesbania, guar, crotalaria, or velvet
beans are often grown to add N and organic matter, while non-legumes such as sorghum-
sudangrass, millet, forage sorghum, or buckwheat are grown for biomass, to smother weeds,
and to improve soil tilth.
A living mulch is a cover crop that is interplanted with an annual or perennial cash crop to
suppress weeds, reduce soil erosion, enhance soil fertility, and improve water infiltration
(Sullivan 2003). Producers should plant a species that is suppressed during the intensive
growth period of the main crop and is taking in excess available nutrients and is growing as the
main crop matures or after it is harvested. Living mulches can be incorporated into bare earthen
rows during a cropping season for corn, vegetables and many other crops grown in the
Chesapeake Bay. For example, New York vegetable growers can interseed ryegrass or clover
2-92 Chapter 2. Agriculture
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
into a standing vegetable crop or plant barley windbreaks in muck-grown onions (Stivers et al.
1998).
A catch crop is a cover crop established after harvesting the main crop and is used primarily to
reduce nutrient leaching from the soil profile but can also be used to fill a niche within a crop
rotation (Sullivan 2003). When applying cover crops for the purpose of capturing and recycling
excess nutrients in the soil profile, NRCS Practice Code 340 specifies that they should be
established and actively growing before the expected period(s) of nutrient leaching and that
cover crop species will be selected for their ability to take up large amounts of nutrients from the
rooting profile of the soil. Deep-rooted crops, such as winter annual grasses (rye, wheat, and
barley) can absorb excess nutrients from the soil and then release them through decomposition
for the subsequent crop, in effect capturing nitrates that could otherwise leach through the root
zone to groundwater (Poole 2004). Greater amounts of N can be taken up by cover crops when
a drought-stricken summer crop has failed to use most of the fertilizer applied or on soils that
mineralize large amounts of N in the fall because of previous manure applications (Weil et al.
2009).
According to the Sustainable Agriculture Network, an excellent resource for information on
cover crops, the best cover crops to use for NO3 conservation are non-legumes (e.g., rye,
sorghum-sudan) that form deep, extensive root systems quickly after cash crops are harvested
(SAN 2007). Cereal rye is the best choice for catching nutrients after a summer crop over much
of the United States. Rye has cold tolerance that allows it to continue to grow in late fall and
develop roots to a depth of 3 feet or more; rye can also grow through mild winter months. Weil
et al. (2009) report that because of their exceptionally deep root system, rapid growth, and
heavy N feeding, forage radish cover crops can take up most of the soluble N left in the soil
profile after summer crops have ceased their uptake. The forage radish takes up N from both
the topsoil and from deep soil layers, typically taking up 112 to 168 kg/ha of N if planted while
soils are warm. Brassica cover crops (e.g., forage radish, oilseed radish, and rape) are new to
the mid-Atlantic region, however, and one of their limitations is the need for early planting.
Farmers in the region have successfully planted Brassica cover crops after harvest of corn
silage, small grains, and sweet corn, but their application in the widespread corn grain-soybean
rotations might require a more risky broadcast seeding into standing crop canopies.
In summary, the top N scavengers include the following (SAN 2007):
1. Excellent N scavengers
a. Rye
b. Sorghum-sudan
c. Radish
Chapter 2. Agriculture 2-93
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
2. Very good N scavengers
d. Annual ryegrass
e. Barley
f. Oats
g. Wheat
h. Rapeseed
i. Berseem clover
3. Good N scavengers
j. Mustards
k. Crimson clover
I. Red clover
m. Woolly pod vetch
If the objective is to best synchronize the use of a cover crop to cycle nutrients, factors such as
the carbon:nitrogen ratio (C:N) should be considered to determine the kill date to match the
release of nutrients with uptake by a following cash crop. Killing or plowing down the cover crop
when the crop is still relatively young is important for N availability because decomposition will
be slower when the plant is in boot stage or later (Bosworth 2006). If the C:N ratio is over 30:1,
N will generally be immobilized during the early stages of the decomposition process (SAN
2007). The C:N ratio of small grain residues is generally lower in young plant tissue, but if the
cover crop is killed too early, this lower C:N ratio results in rapid decomposition of a smaller
amount of residue, reducing ground coverage. The wide C:N ratio of small grain residues,
therefore, must be taken into account for best nutrient management.
In their study of Brassica cover crops Dean and Weil (2009) recommend that the choice of
cover crop should take into consideration both the timing of N release in relation to the N
demands of the subsequent crop and the impact of soil texture on the susceptibility of NO3-N to
leaching in fall and spring. The forage radish, a cover crop that freeze-kills in the Mid-Atlantic
region, releases N from plant tissues early in spring. Although this early N availability can
provide an agronomic advantage for the summer crop, significant amounts of NO3-N can be lost
to leaching if a main crop is not planted early enough to recapture this N. Early planting of a
subsequent summer crop is especially important to minimize spring leaching losses in coarse-
textured, well- to excessively drained soils. Rape, which continues to capture soil NO3-N until
terminated in spring, could be a more appropriate choice of cover crop on coarse-textured soils
when the summer crop will not be planted until late spring.
2-94 Chapter 2. Agriculture
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
Practice Effectiveness
Staver and Brinsfield (1998) investigated the effects of cereal grain winter cover crops on NO3
leaching rates, profile NO3 storage, and NO3 concentrations in shallow groundwater in two
Chesapeake Bay field-scale watersheds planted continuously in corn from 1984 through 1996.
Rye winter cover crops planted after corn harvest consistently reduced NO3-N concentrations in
root zone leachate to less than 1 mg/L during most of the groundwater recharge period and
reduced annual nitrate leaching losses by approximately 80 percent relative to winter-fallow
treatments. Shallow groundwater NO3-N concentrations under long-term continuous corn
production decreased from the 10 to 20 mg/L range to less than 5 mg/L after 7 years of cover
crop use.
In a Maryland study comparing N uptake ability and potential to reduce N leaching, three
Brassica cover crops (forage radish, oilseed radish, and rape) and rye all decreased soil mineral
N losses compared with winter weed control plots by storage of N in plant tissues throughout
the fall and early winter (Dean and Weil 2009). Averaged across three site-years, forage radish
and rape shoots had greater dry matter production and captured more N in fall than rye shoots.
Compared with a weedy fallow control, rape and rye caused similar decreases in soil NO3-N in
fall and spring throughout the sampled profile. During the spring on coarse textured soil, pore
water NO3-N concentrations in freeze-killed radish plots were greater than in control and
overwintering rape and rye plots. On fine textured soil, all cover crops provided a similar
decrease in pore water NO3-N concentration compared with the control. The authors conclude
that on coarse-textured soils, freeze-killed Brassica cover crops should be followed by an early
planted spring main crop but that additional research is needed to determine the optimal
agronomic management of the new cover crops in various types of cropping systems in the
region.
A 2-year study comparing sediment, N, and P runoff losses for cotton managed with winter
fallow and conventional tillage versus cotton managed with a winter wheat cover crop and strip-
tillage, found that the cover crop/strip-till treatment reduced sediment loss for all sampling dates,
especially in 2000 when sediment losses were less than half of those with conventional tillage.
Sediment loss was also reduced with cover crop/strip-til I during the early growing season,
before crop canopy closure, and vegetative field borders further reduced runoff of sediment and
sediment-attached P (Hoyt2005).
Hairy vetch, a legume, was shown to not be effective in reducing NO3 losses on tomato lands in
a study conducted on a Norfolk sandy loam in central Georgia (Sainju 1999). Although hairy
vetch increased tomato N uptake and recovery, it was not effective in reducing NO3-N content
and movement compared with N fertilizer.
Chapter 2. Agriculture 2-95
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
In a field study to determine the potential of a Bermuda grass/ryegrass combination to reduce
the level of Mehlich 3 P that had accumulated in a Savannah soil from broiler litter application
over 30 years, coupled with antecedent litter rates of 0, 4.48, 8.96, 17.9, and 35.8 Mg/ha, Read
et al. (2009) found that annual dry matter (DM) yield and P uptake generally increased as litter
rate increased up to 17.9 Mg/ha. Analysis of Mehlich 3 P in surface soil (0-15 cm depth) at four
sampling dates over 19 months showed reductions of 25, 27, 22, 26, and 29 percent at the five
antecedent litter rates, respectively. Ryegrass-Bermuda grass significantly increased DM yield
and P uptake but did not increase reductions in Mehlich 3 P, as compared to Bermuda grass
winter fallow, and both forage systems removed about 49 kg/ha P and reduced Mehlich 3 P by
about 26 mg/kg annually via five harvests per year.
Sharma and Sahi (2005) examined the phytoremediation potential of Gulf and Marshall ryegrass
grown in a greenhouse under varying conditions of soil P concentration, pH, and temperature,
finding that an increase in plant biomass was proportional to the increasing concentrations of P
up to a level of 10 g of P/kg of soil. Significant effects of both soil pH and temperature on plant
uptake of P were measured, and the researchers concluded that Gulf and Marshall ryegrass
can accumulate high P under optimal conditions and thus reduce soil P concentrations in
successive cropping.
A 3-year field experiment was conducted on sandy loam soils in southwestern Michigan to
investigate the combined effects of N fertilization rates and rye cover crops on NO3 leaching in
inbred maize fields (Rasse et al. 2000). Annual NO3 leaching losses to groundwater in
lysimeters fertilized at 202 kg N/ha averaged 88 kg NO3-N/ha, but rye interseeded with inbred
maize fertilized at 202 kg N/ha sequestered from 46 to 56 kg/ha of excess fertilizer N. Well-
established rye cover crops reduced NO3 leaching by as much as 65 kg N/ha when sediment
losses were less than half of those with conventional tillage. Sediment loss was also reduced
with cover crop/strip-till during the early growing season, before crop canopy closure, and corn
yield. Although fall (but not spring) cover crop DM was 26 percent lower with manure than
without manure, no difference was detected for N (9.4 kg/ha) or P (1.4 kg/ha) uptake. Shoot DM
and N, P, and K uptake increased 29, 41, 31, and 25 percent, respectively, from the cover crop
manure 112 kg N/ha treatment to the cover crop manure 224 kg N/ha treatment, with no
increase above the cover crop manure 224 kg N/ha treatment. Cover crop N, P, and K uptake
were all higher in cover crop manure versus no manure (60.1 versus 35.6 kg N/ha, 9.2 versus
6.6 kg P/ha and 41.3 versus 30.0 kg K/ha, respectively), while corn yield was unaffected by
cover crop and responded positively to manure application (11,022 with manure versus
9,845 kg/ha without manure).
A comparison of a rye winter cover crop and strips of gamagrass (3.05-m wide) placed above
subsurface tiles under a no-till corn and soybean management system on drained fields in Iowa
showed that rye winter cover crops have the potential to reduce the NO3 concentrations and
2-96 Chapter 2. Agriculture
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
loads delivered to surface waters by subsurface drainage systems (Kaspar et al. 2007).
Averaged over 4 years, the rye cover crop treatment reduced flow-weighted NO3-N
concentrations by 59 percent and loads by 61 percent, with no significant reduction in
cumulative drainage. The gamagrass strips did not significantly reduce cumulative drainage, the
average annual flow-weighted NO3 concentrations, or cumulative NO3 loads averaged over the
4-year period.
A winter rye cover crop following corn in Minnesota did not affect subsequent soybean yield but
reduced subsurface tile drainage discharge, flow-weighted mean NO3 concentration, and NO3-N
loss relative to winter fallow, with the magnitude of the effect varying considerably with annual
precipitation (Strock et al. 2004). Over 3 years, subsurface tile-drainage discharge was reduced
11 percent and NO3-N loss was reduced 13 percent for a corn-soybean cropping system with a
rye cover crop following corn versus no rye cover crop.
An incubation experiment designed to assess the effect of freeze-thaw-cycle duration and
frequency on the release of P from catch crop biomass (ryegrass), illustrated the trade-offs of
establishing catch crops in frigid climates, which can enhance P uptake by biomass and reduce
erosion potential but increase dissolved P runoff (Bechmann et al. 2005). Before freezing and
thawing, TP in runoff from catch-cropped soils was lower than from manured and bare soils
because of lower erosion. Repeated freezing and thawing significantly increased WEP from
catch crop biomass and resulted in significantly elevated concentrations of dissolved P in runoff
(9.7 mg/L) compared with manured (0.18 mg/L) and bare soils (0.14 mg/L). Catch crop WEP
was strongly correlated with the number of freeze-thaw cycles. Freezing and thawing did not
change the WEP of soils mixed with manures, nor were differences observed in subsurface
losses of P between catch-cropped and bare soils before or after manure application.
A 2-year field lysimeter study was established in Uppsala, Sweden, to evaluate the effect of a
perennial ryegrass cover crop interseeded in barley on NO3-N leaching and availability of N to
the main crop (Bergstrom and Jokela 2001). Barley yields and total fertilizer N uptake in year
one (1992) were unaffected by cover crop. Study results clearly show that a ryegrass cover
crop, interseeded in spring barley for one season, substantially reduced NO3-N leaching. In that
case, leaching was reduced by two-thirds in the first year and by more than 50 percent over a
2-year period. The cover crop reduced NO3-N concentration in the leachate to levels (about
3 mg/L) well below the U.S. and European drinking water standards, compared with
approximately 15 mg/L without a cover crop. Barley yield was not significantly affected by the
presence of the interseeded ryegrass cover crop during the first year, although it was reduced
somewhat during the residual year.
In a 2-year lysimeter study in Switzerland, three non-winter hardy catch crops (sunflower, yellow
mustard, and phacelia) were compared with fallow at low (4 g N/m2/yr) and high (29 g N/m2/yr)
Chapter 2. Agriculture 2-97
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
N input levels in a spring wheat-catch crop succession (Herrera and Liedgens 2009). Catch
crops reduced N leaching by 31-36 percent and by 16-24 percent versus fallow at the low-N
and high-N input levels, respectively, but the capacity of the catch crop for recycling N in situ
and to increase grain yield and N uptake of the successive spring wheat varied among catch
crop species and depended on the level of N input. Although the catch crops reduced N
leaching for the entire crop succession, it was mostly from reductions during the periods when
water percolation and NO3 concentration in the soil solution were high (i.e., winter and autumn).
A significant amount of the N saved from leaching during autumn and winter was lost during the
spring wheat season.
Brandi-Dohrn et al. (1997) used a randomized complete-block split plot design with three N
application rates (0 to 280 kg N/ha/yr) to compare winter NO3-N leaching losses under winter-
fallow and a winter cereal rye cover crop following the harvest of sweet corn or broccoli. At the
recommended N rate for the summer crops, NO3 leaching losses were 48 kg N/ha under sweet
corn-winter-fallow for winter 1992-1993, 55 kg N/ha under broccoli-winter-fallow for winter 1993-
1994, and 103 kg N/ha under sweet corn-winter-fallow for winter 1994-1995, which were reduced
to 32, 21, and 69 kg N/ha, respectively, under winter cereal rye. For the first two winters, most of
the variation (61 percent) in NO3 leaching was explained by N rate (29 percent), cereal rye N
uptake (17 percent), and volume of leachate (15 percent). Seasonal, flow-weighted concentrations
at the recommended N rate were 13.4 mg N/L under sweet corn-winter-fallow (1992-1993),
21.9 mg N/L under broccoli-winter-fallow, and 17.8 mg N/L under sweet corn-winter-fallow (1994-
1995), which were reduced by 39, 58, and 22 percent, respectively, under winter cereal rye.
In Denmark, a 24-year-old permanent field trial on coarse sand with spring-sown crops (wheat)
was used in a NO3 leaching study to determine both the effect of long-term cover crop use
compared with the introduction of perennial ryegrass as a cover crop on plots with a history of
no previous cover crop use as well as the effect of discontinuing long-term use of ryegrass as a
cover crop compared with no previous cover crop use (Hansen et al. 2000). From the 4-year
average for two N rates (60 and 120 kg/N ha/yr), it was found that leaching was 14 kg/N ha/yr or
29 percent higher in plots with long-term previous cover crop use than in plots without. The
effect of previous long-term use of ryegrass as a cover crop lasted at least 4 years, and the
authors concluded that if the higher N mineralization from long-term use of a cover crop is not
taken into consideration by adjusting the cropping system, the reduction in NO3 leaching caused
by the cover crop might not be as significant in the long term.
Van Vliet et al. (2002) compared different fall-manure application strategies on runoff and
contaminant transport from silage corn land in the Lower Fraser Valley of British Columbia.
They had three treatments: a control that did not receive manure in the fall, manure broadcast in
the fall on corn stubble, and manure broadcast in the fall on corn stubble with an established
relay crop. Runoff, solids, and nutrients loads from natural precipitation were measured on
2-98 Chapter 2. Agriculture
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
replicated experimental plots (0.0125 ha) from 1996 to 1998. Fall-applied manure on 3-5
percent sloping silage corn without a relay crop yielded high suspended solids export of
between 7 and 14 Mg/ha/yr and high nutrient transport with mean annual TKN, P, and K losses
of 98, 21, and 63 kg/ha respectively. Compared with no relay crop, intercropping silage corn
with a relay crop of Italian ryegrass reduced the mean annual runoff and suspended solid load
by 53 and 74 percent, respectively, TKN load by 56 percent, P load by 42 percent, K load by
31 percent, and Cu load by 57 percent. Even though total nutrient loads were lower with the
relay crop treatment, all fall manure treatments including the relay crop resulted in nutrient loads
above local guidelines for the first three runoff events immediately following application.
Practice Costs
The Chesapeake Bay Commission (2004) evaluated 34 nutrient and sediment-reduction
practices representing a wide range of specific actions associated with wastewater treatment
plants, agriculture, urban stormwater, land preservation, forestry, and air pollution. The analysis
resulted in identifying six measures that could achieve a substantial portion of the N, P, and
sediment-reduction goals set for the period 2002-2010 in the Chesapeake 2000 agreement.
One of those practices is enhanced adoption of late cover crops and use of early cover crops to
absorb excess nutrients in the soil. The report estimates that implementing fall cover crops at
the maximum extent feasible (0.83 million hectares) in the watershed could achieve annual N
reductions of 6,893 Mg of N at $9.54/kg (2010 dollars), 99.8 Mg of P, and 49.9 Mg of sediment
at no additional cost. Maximum feasible implementation of early cover crops could provide
annual reductions of 3,673 Mg of N at $5.90/kg and 99.8 Mg of P and 049.9 Mg of sediment at
no additional cost.
Factors affecting the economics of cover crop use consist of the following (SAN 2007):
• The cash crop grown
• The cover crop selected
• Time and method of establishment
• Method of termination
• The cash value applied to the environment, soil productivity, and soil protection benefits
derived from the cover crop
• The cost of N fertilizer and the fertilizer value of the cover crop
• The cost of fuel
The economic picture is most affected by seed costs, energy costs and N fertility dynamics in
cover crop systems (SAN 2007). Cover crop seed costs vary considerably from year to year and
Chapter 2. Agriculture 2-99
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
from region to region, but historically, legume cover crops cost about twice as much to establish
as small grain covers. The increased cost of the legume cover crop seed can be offset by the
value of N that legumes can replace. Depending on the system in place on a farm, legume
cover crops can replace 50 to 112 kg N/ha. On the other hand, a rye cover crop terminated at a
late stage of growth might require an additional 22-34 kg N/ha because of N immobilization by
the wide C:N ratio rye residue. Thus, the difference in cost between a rye cover crop and a
legume cover crop would be offset by the value of 73 to 140 kg N/ha. At a price of $0.21/kg N
(2010 dollars), it would be worth $75/ha to $145/ha.
The highest cost for annual cover crops is for the seed, with hairy vetch and crimson clover
typically ranging from $1.30 to $3.90/kg (2010 dollars) (Sullivan 2003). With a 22.4-kg/ha
seeding rate, seed costs range from $30 to $86/ha. With a 28-kg/ha seeding rate at $2.22/kg
and a $7.69 no-till drilling cost, it would cost $82/ha to plant this cover crop.
Saleh et al. (2005) used the modified SWAT (SWAT-M) and FEM (Farm-level Economic Model)
models to evaluate the environmental and economic impacts of various BMP scenarios often
adopted by local farmers to reduce sediment and nutrient loadings (in particular NO3-N).
Measured values of water quality indicators from the Walnut Creek watershed in central Iowa
were used to verify the capability of SWAT-M to predict the impact of late-spring NO3 test
(LSNT) and rye cover crop management on NO3-N reduction at the subbasin level. The results
obtained from SWAT-M simulation results, similar to field measurement data, indicated a
25 percent reduction in NO3-N under the LSNT scenario. FEM results indicated a corresponding
increased annual cost of $6.69/ha (2010 dollars) across all farms in the watershed. Simulating
other scenarios, including winter cover cropping and a combination of LSNT and cover cropping
at different adoption rates within WCW, resulted in a progressive reduction in sediment and
nutrient losses as adoption rates increased. Using the rye cover crop added about $28/ha to
$39/ha to the annual cost of the average farm, indicating that some cost-share support might be
necessary to encourage farmers to use winter cover crops.
In an application of the Annualized Agricultural Nonpoint Source pollutant loading model
(AnnAGNPS 2.1) to a 12-ha Mississippi Delta Management System Evaluation Area (MDMSEA)
subwatershed, cover crops, filter strips, grade control pipes, and impoundments were modeled
in combination with three tillage systems: conventional tillage, reduced tillage, and no-till (Yuan
et al. 2002). Costs of management practices were estimated using 2001 state average prices
for Mississippi, and amortized fixed costs—using a 25-year planning horizon and interest rates
of both 5 percent and 10 percent—were combined with direct annual costs into total annual cost
estimates. AnnAGNPS predicted that no-till alone, reduced tillage with winter cover and an
edge-of-field pipe, or conventional tillage with a small permanent impoundment (covering less
than 3 percent of the watershed) would all reduce sediment yield by at least 50 percent. The
most cost-effective BMPs were managing volunteer winter weeds as cover crops and various
2-100 Chapter 2. Agriculture
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
types of edge-of-field grade-control pipes. The average marginal cost using BMPs for sediment
yield reduction was about S9.84/MT ($8.98/t) (2010 dollars) for conventional and reduced tillage.
The cost was higher, about S13.16/MT ($11.93/t), for no-till because the practice of no-till alone
reduced sediment yield by half, and further marginal reductions were more expensive.
An assessment of options to address NO3 problems in the Neuse River Basin of North Carolina
concluded that cover crops can reduce N loading to shallow groundwater by 5 to 15 percent
(Wossink2001). Conservation tillage, including cover crops, is identified as one of the three
best options for N reduction in the Piedmont region, and the cost of a wheat cover crop is
estimated at $230/ha with $0 in net receipts, for a net revenue of -$230/ha.
Franzluebbers (2005) summarizes research on some of the key components that could produce
viable integrated crop-livestock production systems in the Southeast: sod-based crop rotation,
cover cropping, intercropping, and conservation tillage. Despite its agronomic benefits, adopting
cover cropping appears to be limited because of cost without immediate economic benefit, but
the author suggests that grazing of cover crops could provide such an immediate economic
benefit to producers. On the basis of the research reviewed, barriers to adopting integrated
crop-livestock systems include lack of experience or time to manage both the crops and
livestock. Franzluebbers reviewed several studies regarding economic returns from grazing
livestock and found the following:
• Livestock increased labor required on an average North Dakota farm by about
50 percent, but only about 30 percent of the additional time competed directly during
critical crop management. Net economic return attributed to livestock increased whole
farm income by about 20 percent.
• Ten steers and heifers were grazed on a 4-ha area of rye or ryegrass cover crop at the
Sunbelt Agricultural Exposition near Moultrie, Georgia. The equivalent of $346 ±$69/ha
(2010 dollars) greater gross income was generated in the value of animal gain
(assuming $1.95/kg animal gain).
• A 3-year experiment was conducted at Headland, Alabama, to compare the effect of oat
and ryegrass winter cover crops under cattle grazing on cotton and peanut production
managed under different tillage systems. Net return from winter grazing of cover crops
(5 head/ha for 80 d) was $206 to $223/ha/yr.
• Using an economic model comparing a conventional system (53 ha cotton, 27 ha
peanut) with a sod-based rotation system (20 ha cotton, 20 ha peanut, 40 ha
bahiagrass) on a typical small farm in Florida, net profit was expected to be
$17,483/year on a conventional farm and $49,967/year on a sod-based farm with cattle
grazing the second year bahiagrass.
Chapter 2. Agriculture 2-101
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
3.4 Pasture Land Management
Implementation Measure A-14:
Minimize nutrient and soil loss from pasture land by maintaining uniform livestock
distribution, keeping livestock away from riparian areas, and managing stocking
rates and vegetation to prevent pollutant losses through erosion and runoff.
Livestock can obtain their nutrients through feed supplied to them in a confined livestock facility,
through forage, or through a combination of forage and feed supplements. Forage systems can
be pasture-based or rangeland-based.
There are important differences between rangeland and pasture. Range/and refers to those
lands on which the native or introduced vegetation (climax or natural potential plant community)
is predominantly grasses, grass-like plants, forbs, or shrubs suitable for grazing or browsing.
Rangeland includes natural grassland, savannas, many wetlands, some deserts, tundra, and
certain forb and shrub communities. Pastures are those improved lands that have been seeded,
irrigated, and fertilized and are primarily used for producing adapted, domesticated forage
plants for livestock. Other grazing lands include grazable forests, native pastures, and crop
lands producing forage.
The major differences between rangeland and pasture are the kind of vegetation and level of
management that each land area receives. In most cases, range supports native vegetation that
is extensively managed through the control of livestock rather than by agronomy practices, such
as fertilization, mowing, or irrigation. Rangeland also includes areas that have been seeded with
introduced species (e.g., clover or crested wheatgrass) but are managed with the same
methods as native range. For both rangeland and pasture, the key to good grazing practice is
vegetative management, i.e., timing of grazing should be managed to ensure adequate
vegetative regrowth and soil stability.
Pastures are represented by those lands that have been seeded, usually with introduced
species (e.g., legumes or tall fescue) or in some cases with native plants (e.g., switchgrass or
needle grass), and that are intensively managed using agronomy practices and control of
livestock. Permanent pastures are typically based on perennial, warm-season (e.g., Bermuda
grass) or cool-season (e.g., tall fescue) grasses and legumes (e.g., warm-season alfalfa, cool-
season red clover), while temporary pastures are generally plowed and seeded each year with
annual legumes (e.g., warm-season lespedezas, cool-season crimson clover) and grasses such
as warm-season pearl millet and cool-season rye (Johnson et al. 1997). Plants for pastures
should be selected on the basis of climate, soil type, soil condition, drainage, livestock type and
expected forage intake rates, and the type of pasture management to be used. Management of
2-102 Chapter 2. Agriculture
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
pH and soil fertility is essential to both establishing and maintaining pastures (Johnson et al.
1997). In some climates (e.g., Georgia), overseeding of summer perennials with winter annuals
is done to provide adequate forage for the period from mid-winter to the following summer.
Pollutant runoff from pasture land can be controlled by managing animal stocking rates and
maintaining vigorous vegetation to provide for soil stability and nutrient recycling. Osmond et al.
(2007) recommend using those practices that encourage more uniform livestock distribution
over the pasture; riparian areas should not be used as shade paddocks, holding areas, or
feeding areas; and access to riparian areas should be limited and should not occur when soils
are wet or boggy and when acceptable forage is available on non-riparian sites within the same
grazing unit. Good pasture management maintains stocking rates and vegetation to prevent
pollutant losses through erosion and runoff, and silvopasture techniques integrate trees into
pastures to improve nutrient uptake and vegetation stability. Forestry practices and
methodologies that can be incorporated into silvopasture are described in Chapter 4.
Practice Effectiveness
Pasture management
In a Georgia plot study, Butler et al. (2008b) compared runoff and sediment and nutrient export
from poorly drained and well-drained riparian soils where heavy or light grazing pressure by
cattle was simulated. Runoff volume was generally greater from heavily grazed areas than from
lightly grazed areas. Light-use plots were effective at minimizing export of TSS on both soils
(less than 30 kg/ha). Mean TP export was fourfold greater from heavy-use plots than from light-
use plots on both soils. While export of NO3-N was unaffected by grazing pressure and soil
drainage, mean NH4-N and TN export from poorly drained heavy-use plots was greater than
fivefold that from well-drained light-use plots. Results indicate that livestock heavy-use areas in
the riparian zone can export substantial TSS and nutrients, especially on poorly drained soils.
However, when full ground cover is maintained on well-drained soils, TSS and nutrient losses
can be limited.
Sistani et al. (2008) investigated the effect of pasture management and broiler litter application
rate on nutrient runoff from Bermuda grass pasture plots in Kentucky. Runoff was 29 percent
greater from grazed than hayed pastures regardless of the litter application rate. There was
greater inorganic N in the runoff from grazed paddocks when litter rate was based on N rather
than P. The mean TP loss per runoff event for all treatments ranged from 7 to 45 g/ha, and the
grazed treatment with litter applied on an N basis had the greatest TP loss. The SRP was
greater for treatments with litter applied on an N basis regardless of pasture management. Litter
can be applied on an N basis if the pasture is hayed and the soil P is low. In contrast, litter rates
should be applied on a P-basis if the pasture is grazed.
Chapter 2. Agriculture 2-103
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
Cattle did not cause substantial damage to the soil when they were put on fields to graze cover
crops in Georgia (Franzluebbers and Stuedemann 2008). The grazing had little effect on soil
bulk density or the stability of macroaggregates in. There was a slight tendency for water
infiltration rate to be lower with grazing of cover crops (5.6 mm/min) than when ungrazed
(6.9 mm/min).
In New Zealand, McDowell and Houlbrooke (2009) assessed restricted grazing and applying
alum for their potential to decrease contaminant loss from winter grazing of forage crops.
Volumes of surface runoff and loss of P and sediment showed significant differences between
the control treatments (i.e., no mitigation) with cattle crop (88 mm surface runoff) greater than
sheep crop (67 mm) and greater than sheep pasture (33 mm). Restricted winter grazing and
alum application after grazing significantly decreased P losses in surface runoff under cattle
(from 1.4 to 0.9 kg P/ha, 36 percent) and sheep (from 1.0 to 0.7 kg/P/ha, 30 percent). In cattle-
grazed plots, restricted grazing also decreased suspended sediments by 60 percent.
Owens and Shipitalo (2009) evaluated two systems of over-wintering cattle in Ohio. Vegetative
cover in the continuous wintering area frequently decreased to less than 50 percent by late
winter/early spring while it remained at or near 100 percent in the rotational system. Annual
runoff from the rotational wintering system was 69 percent lower than from the continuous
wintering system; sediment loss was also reduced by 91 percent under the rotational system
compared to continuous wintering. Surface runoff losses of N from the continuous system were
double those from the rotational system during the dormant season. Some of the differences
could be attributed to higher cattle occupancy rate in the continuous wintering system.
In North Carolina, Butler et al. (2007) reported that mean NO3. export was greatest from bare
ground and was reduced by 31 percent at 45 percent cover. Mean TN export was greatest from
bare ground and was reduced by at least 85 percent at cover levels from 45 to 95 percent.
Whereas site did not affect N export, results indicate that cover and time of rainfall following
manure deposition are important determinants of the effect of riparian grazing.
In a review of experimental data from the Northeast United States, Stout et al. (2000) assessed
the relationships between stocking rate and NO3-N leaching losses beneath an intensively
grazed pasture. A relatively low cumulative seasonal stocking rate of about 200 mature Holstein
per hectare could result in a 10 mg/L NO3-N concentration in the leachate beneath a fertilized,
intensively grazed pasture. That means that while management intensive grazing can improve
farm profitability and help control erosion, it can have a significant negative effect on water
quality beneath pastures.
Lyons et al. (2000) compared bank erosion, fish habitat characteristics, trout abundance, and a
fish-based index of biotic integrity (IBI) among stations with riparian continuous grazing,
2-104 Chapter 2. Agriculture
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
intensive rotational grazing, grassy buffers, or woody buffers along 23 trout stream reaches in
Wisconsin. After statistically factoring out watershed effects, stations with intensive rotational
grazing or grassy buffers had the least bank erosion and fine substrate in the channel.
Continuous grazing stations had significantly more erosion and, with woody buffers, more fine
substrate. Station riparian land use had no significant effect on width/depth ratio, cover, percent
pools, habitat quality index, trout abundance, or IBI score.
From Minnesota, Magner et al. (2008) reported that low IBI scores were associated with
streams draining continuously grazed pasture, while higher IBI scores occurred on ungrazed
sites. Ungrazed sites were associated with reduced soil compaction and higher bank stability,
whereas continuously grazed sites showed increased soil compaction and lower bank stability.
Short-duration grazing sites were intermediate.
Table 2-21. Summary of reported practice effects resulting from pasture management
Location
Georgia
Kentucky
Georgia
New
Zealand
Study
type
Plots
Plots
Field
Field
Practice
Stocking rate
Pasture
management,
litter
application rate
Grazing cover
crops
Restricted
grazing, alum
Practice effects
Runoff volume was greater from heavy use
than from light use. Light-use plots were
effective at minimizing export of TSS. Mean TP
export was fourfold greater from heavy-use
plots than from light-use plots. While export of
NO3-N was unaffected by grazing pressure
and soil drainage, mean NH4-N and TN export
from poorly drained heavy-use plots was
greater than fivefold that from well-drained
light-use plots.
Runoff was 29% greater from grazed than
hayed pastures regardless of litter application
rate. There was greater inorganic N in the
runoff from grazed paddocks when litter rate
was based on N rather than P. The mean TP
loss per runoff event for all treatments ranged
from 7 to 45 g/ha and the grazed treatment
with litter applied on N basis had the greatest
TP loss.
Grazing of cover crops had little effect on soil
bulk density; stability of macroaggregates in
water was unaffected by grazing of cover
crops.
Restricted winter grazing and alum application
after grazing significantly decreased P losses
in surface runoff under cattle (from 1 .4 to 0.9
kg P/ha, 36%) and sheep (from 1 .0 to 0.7
kg/P/ha, 30%). In cattle grazed plots, restricted
grazing also decreased suspended sediments
by 60%.
Source
Butler et al.
2008b
Sistani et al.
2008
Franzluebbers
& Stuedemann
2008
McDowell and
Houlbrooke
2009
Chapter 2. Agriculture
2-105
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
Table 2-21. Summary of reported practice effects resulting from pasture management
(continued)
Location
Ohio
North
Carolina
Northeast
U.S.
Wisconsin
Minnesota
Study
type
Field
Plots
Review
Field
Field
Practice
Cattle wintering
systems
Vegetative
cover
Intensive
grazing
Rotational
grazing
Short-duration
grazing
Practice effects
Annual runoff from the rotational wintering
system was 69% lower than from the
continuous wintering system; sediment loss
was also reduced by 91% under the rotational
system vs. continuous wintering. Surface
runoff losses of N from the continuous system
were double those from the rotational system
during the dormant season.3
Mean NO3-N export from bare ground plots
was greatest from bare ground and was
reduced by 31% at 45% cover. Mean TN
export was greatest from bare ground and was
reduced by at least 85% at cover levels from
45%-95%.
A relatively low cumulative seasonal stocking
rate of about 200 mature Holstein/ha could
result in a 10 mg/L NO3-N concentration in the
leachate beneath a fertilized, intensively
grazed pasture.
Stations with intensive rotational grazing or
grassy buffers had the least bank erosion and
fine substrate in the channel. Continuous
grazing stations had significantly more erosion
and more fine substrate. Station riparian land
use had no significant effect on width/depth
ratio, cover, percent pools, habitat quality
index, trout abundance, or IBI score.
Low IBI scores associated with streams
draining continuously grazed pasture; higher
IBM scores occurred on ungrazed sites.
Ungrazed sites associated with reduced soil
compaction and higher bank stability;
continuously grazed sites showed increased
soil compaction and lower bank stability. Short-
duration grazing sites were intermediate.
Source
Owens and
Shipitalo 2009
Butler et al.
2007
Stout et al.
2000
Lyons et al.
2000
Magneret al.
2008
Note:
a. Some of the differences could be attributed to higher cattle occupancy rate in the continuous wintering system
Silvopasture
In Missouri, Garrett et al. (2004) reported that many cool-season forages benefit from
40 percent to 60 percent shade, and grazing trials in such conditions have proven to be
successful. Also in Missouri, Kallenbach et al. (2006) reported that cumulative forage production
in annual ryegrass/cereal rye planted into a 6- to 7-year-old forested stand was reduced by
2-106
Chapter 2. Agriculture
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
approximately 20 percent compared to the same forages planted in open pasture. However,
beef heifer average daily gain and gain/ha were equal for both treatments, suggesting that a
silvopasture system likely would not sacrifice livestock production in the system. In Florida,
Bambo et al. (2009) documented 56 percent reduction in NO3 concentrations under silvopasture
compared to conventional open pasture.
Blazier et al. (2008) evaluated soil nutrient dynamics, loblolly pine nutrient composition, and
loblolly pine growth of an annually fertilized silvopasture on a well drained soil in Louisiana in
response to fertilizer type, litter application rate, and subterranean clover. Litter stimulated
loblolly pine growth, and neither litter treatment produced soil test P concentrations above runoff
potential threshold ranges. However, both litter treatments led to accumulation of P in upper soil
horizons relative to inorganic fertilizer and unfertilized control treatments. Subterranean clover
kept more P sequestered in the upper soil horizon and conferred some growth benefits to
loblolly pine. The authors concluded that although the silvopasture systems had a high capacity
for nutrient use and retention, litter should be applied less frequently than in their study to
reduce environmental risks.
In Florida, Michel et al. (2007) reported that water-soluble P concentrations in the upper soil
layer ranged from 4 to 11 mg/kg for the silvopasture sites and 10 to 23 mg/kg in the treeless
pasture sites, with higher P concentrations in the treeless pasture at each location. TP storage
capacity in the upper 1-m depth ranged from 342 to 657 kg/ha in the silvopasture sites and 60 to
926 kg/ha in the treeless pasture sites (a negative value indicates that the soil is a P source).
The results suggest that P builds up within the soil profile (P-sat increases) and therefore the
chances for loss of P from soil to waterbodies were less from silvopastures than from treeless
pastures.
Nair et al. (2007) monitored soil N and P concentrations under a treeless pasture, a pasture
under 20-year-old trees, and a pasture of native vegetation under pine trees in Florida. P
concentrations were higher in treeless pasture (mean: 9.11 mg/kg in the surface) compared to
silvopastures (mean: 2.51 mg/kg), and ammonium-N and NO3-N concentrations were higher in
the surface horizon of treeless pasture. The more extensive rooting zones of the combined
stand of tree + forage might have caused higher nutrient uptake from silvopastures than
treeless system. Further, compared to treeless system, soils under silvopasture showed higher
P storage capacity.
Chapter 2. Agriculture 2-107
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
Table 2-22. Summary of reported practice effects resulting from silvopasture
State
Missouri
Missouri
Florida
Louisiana
Florida
Florida
Study
type
Field
Field
Field
Field
Field
Field
Practice
Forage planted
in forest stand
Forage planted
in forest stand
Silvopasture
Silvopasture
fertilized with
poultry litter
Silvopasture
Silvopasture
Practice effects
Cool-season forages benefit from 40% to 60%
shade and grazing trials in such conditions have
proven to be successful
Cumulative forage production in annual
ryegrass/cereal rye planted into a 6-7 year-old
forested stand was reduced by about 20% vs. the
same forages planted in open pasture. However,
beef heifer average daily gain and gain/ha were
equal for both treatments.
56% reduction in NO3 concentrations under
silvopasture compared to conventional open
pasture
Litter stimulated tree growth, and did not produce
soil test P concentrations above runoff potential
threshold ranges. However, litter treatments led
to accumulation of P in upper soil horizons vs.
inorganic fertilizer and unfertilized control
treatments. Subterranean clover kept more P
sequestered in the upper soil horizon and
conferred some growth benefits to loblolly pine.
Water-soluble P concentrations in the upper soil
layer on treeless sites (1 0 to 23 mg/kg) exceeded
those on silvopasture sites (4 to 1 1 mg/kg) at
each location. TP storage capacity in the upper
1-m depth was 342 to 657 kg/ha in the
silvopasture sites and -60 to 926 kg/ha in the
treeless pasture sites (a negative value indicates
that the soil is a P source).
Surface soil P concentrations were higher in
treeless pasture (mean: 9.11 mg/kg) compared to
silvopastures (mean: 2.51 mg/kg), and
ammonium-N and NO3-N concentrations were
higher in the surface horizon of treeless pasture.
The more extensive rooting zones of the
combined stand of tree + forage might have
caused higher nutrient uptake from silvopastures
than treeless system. Further, compared to
treeless system, soils under silvopasture showed
higher P storage capacity.
Source
Garrett et al.
2004
Kallenbach et
al. 2006
Bambo et al.
2009
Blazier et al.
2008
Michel et al.
2007
Nairetal.2007
Practice Costs
Giasson et al. (2003) examined the cost-effectiveness and the risk of P loss associated with
various combinations of manure management options for a typical mid-sized dairy farm in New
York using mathematical programming techniques and utility functions to select optimum
2-108
Chapter 2. Agriculture
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
management practices. Compared with current practices, the recommended combination of
practices resulted in an approximate 45 percent reduction in the mean area-weighted P index
(64.2 versus 36.1) for a cost (2008 dollars) increase of less than 2 percent ($173,086 versus
$175,740) (2010 dollars).
Prescribed grazing plan development costs about $7.50/ac in Virginia, with typical total costs of
about $900 (USDA-NRCS 2010). Implementing the plan runs about $70/ac with total costs
typically in the neighborhood of $8,300. Forage harvest management costs are about $28/ac for
record keeping and forage tissue testing ($421 typical total cost), and about $17/ac for record
keeping and monitoring only ($260 typical total cost). Grass establishment for pasture and hay
land costs are approximately $260/ac for native warm season grass and $330/ac for cool
season grass, with typical total costs of about $2,600 for warm-season grass and $3,300 for
cool-season grass. Renovating pasture and hay land with legumes costs nearly $30/ac for
broadcast and $40/ac for drilling; typical total costs in Virginia are just under $300 for broadcast
and $400 for drilling.
3.5 Drainage System Design
Reduction of nutrient loads from agricultural drainage water has elements of source control
(e.g., nutrient management, crop rotations), in-field control (e.g., the drainage system), and
edge-of-field control (e.g., controlled drainage, bioreactors). Basic subsurface drainage system
design consists of field or lateral drains to collect drainage from the fields, collectors or mains to
collect the water from the lateral drains, and a ditch or other conveyance to convey the collected
water away from the field. The size, depth, and spacing of the drains are key determinants of
the drainage rate or drainage intensity.
Implementation Measure A-15:
Where drainage is added to an agricultural field, design the system to minimize the
discharge of N.
Practice Effectiveness
Several studies performed under different conditions document significant reductions in both
discharge volume and NO3 loads for shallower and more widely spaced drains compared to
deeper and more closely spaced drains (Table 2-23). However, other studies show no
significant effect or increases in NO3 loads.
Chapter 2. Agriculture 2-109
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
Table 2-23. Measured effects of changes in drain depth and spacing
State
North
Carolina
Minnesota
Illinois'
Indiana
Soils and
crops
Swine
wastewater
applied
Poorly
drained
soils; corn-
soybean0
Poorly
drained
soils;
soybeans-
corn
Clermont
silt loam,
corn for
9 yr, then
6 yr corn-
soybean
Study
type
Plot
Plot
Plot
Plot
Practice
Depth
(m)
0.75
0.9
0.9
1.2
0.61
0.61
0.91
0.75
0.75
0.75
Spacing
(m)
12.5
15.24
15.24
30.48
20
20
10
Drainage
Intensity
(mm/d)
13
13
13
Reference practice
Depth
(m)
1.5
1.2
0.9
1.2
0.91
1.22
1.22
0.75
0.75
0.75
Spacing
(m)
25
30.48
30.48
30.48
5
10
5
Drainage
Intensity
(mm/d)
51
51
51
Reduction vs.
reference practice
Q
42%
20%d
24%d
N/S
N/S
43%9
62%9
33%9
42%i
19%!
28%i
N03-N
Cone.
-217%a
N/S
N/S
19%e
-1 5%e
N/Se
N/Se
N/Se
N/S
N/S
N/S
N03-N
Load
26%b
18%d
23%d
48%
-1%
37%h
51%h
22%h
44%!
21%!
28%!
Source
Burchell et
al. 2005
Sands et
al. 2008
Cooke, et
al. 2002
Kladivko et
al. 2004
KEY: Q=drainage water discharge, N/S=no significant change
Notes:
a. Significant increase in 2001 (7.6 mg/L shallow vs. 2.4 mg/L deep), but not significant in 2002 (15.7 mg/L vs. 12.8 mg/L).
b. Significant decrease in 2002 (27.3 kg NO3-N/ha shallow vs. 36.9 kg NO3-N/ha deep) but N/S over a 21-month period.
c. NO3 concentration (4.4 mg/L greater for corn) and load (45% greater for corn) were significantly affected by crop type.
d. Using adjusted means.
e. Flow-weighted concentrations.
f. Findings based on only 1 year of monitoring data.
g. Changes in cumulative flow were greater than changes in flow for discrete events.
h. Similar load reductions were achieved for discrete events.
i. Average of two blocks over 15 years.
A detailed analysis of published field data and simulation results demonstrated that N losses
increase with drainage rates or drainage intensity because of lowered water tables, increased
mineralization of organic matter, reduced denitrification, and increased rates of subsurface
water movement to surface waters (Skaggs et al. 2005). Factors affecting drainage rates
include drain depth, drain spacing, soil properties, hydraulic conductivity, drainable porosity, the
depth of the profile through which water moves to the drains, surface depressional storage,
drain diameter, drain envelopes, the size and configuration of openings in the drain tube walls,
the hydraulic capacity of the drainage network to remove water from the field, and management
(e.g., controlled drainage) of the drainage outlet. Additional factors affecting NO3 losses through
drain tiles include climate, fertilization rate, and crop rotations.
2-110
Chapter 2. Agriculture
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
In a North Carolina study of the effect of subsurface drain depth on NO3 losses from plots
receiving swine wastewater applications, the shallow drainage system (0.75 m deep and 12.5 m
apart) had 42 percent less outflow than the deeper drainage system (1.5 m deep and 25 m
apart), and NO3 export from the shallow drains (8 kg/ha in 2001 and 27 kg/ha in 2002) was
significantly (p = 0.10) lower than from the deeper drains (6 kg/ha in 2001 and 37 kg/ha in 2002)
in 2002, but not for the entire 21-month period (Burchell et al. 2005). Lower NO3 concentrations
were observed in the shallow groundwater beneath the shallow drainage plots because of
higher water tables and likely increased denitrification, but NO3 concentrations in the drainage
water from the shallow drains increased, possibly because of preferential flow paths to the
drains from the surface (hence, shorter retention times) and soil pore flushing near the shallow
drains.
Nine subsurface drainage plots in Minnesota were monitored for 5 years to investigate the role
of subsurface drainage depth and drainage intensity on NO3 loads to subsurface drains (Sands
et al. 2008). Three plots had a depth of 120 cm (conventional depth) and a spacing of 24 m,
resulting in a calculated drainage intensity of 13 mm/d (conventional rate), while two plots had a
depth of 90 cm and a spacing of 18 m that was calculated to also achieve the conventional
drainage intensity of 13 mm/d. Two plots each had depth/spacing combinations of 120 cm/12 m
and 90 cm/9 m, designed to simulate the intensification of drainage systems experienced in the
area. Analysis of aggregated data showed that both shallower and less intense drain systems
reduced both discharge (20 percent and 24 percent, respectively) and NO3 loading (18 percent
and 23 percent, respectively), but not flow-weighted NO3-N concentration. Interaction effects,
however, indicated that intense drainage increased NO3 concentration for shallow drainage but
diluted NO3 concentrations for drains at conventional depth. Because of that, NO3 loads
increased significantly for shallow drainage when combined with increased drainage intensity,
while NO3 loads for conventional drainage depth remained at a similar level despite increased
drainage intensity.
In a one-year study of tile effluent from drainage tiles installed at different depths in a 16-ha field
in Illinois, Cooke et al. (2002) found that tile discharge decreased with decreasing tile depth for
tiles at 0.61 m, 0.91 m, and 1.22 m depth. Cumulative discharge from the monitored tile lines at
0.61 m and 0.91m depth were 43 percent and 33 percent less, respectively, than discharge from
the tile line at 1.22 m. Average NO3 load reductions for the 0.61 m and 0.91 m tile lines, when
compared to the tile line at 1.22 m, were 51 percent and 22 percent, respectively. There was no
relationship between flow-weighted NO3 concentration and tile depth, and the authors noted a
need for more data to validate the findings.
A 15-year drainage study in Indiana to evaluate three drain spacings (5, 10, and 20 m) installed
at a depth of 0.75 m showed that both discharge and NO3 load were reduced significantly as
drain spacing increased but that flow-weighted NO3 concentration did not vary with drain
Chapter 2. Agriculture 2-111
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
spacing (Kladivko et al. 2004). Differences in NO3 loads with spacing occurred primarily during
the years with continuous corn, high fertilizer N rates, and no cover crop.
Drury et al. (2009) concluded that the lower flow volumes measured for controlled drainage
systems were due to the shallower effective tile depth (0.3 m) relative to uncontrolled drainage
(0.6 m) because the water level in the soil must reach the 0.3-m level before any water would
drain from the tiles. Hence, there is additional storage capacity for water in the soil from the
0.6-m depth to the 0.3-m effective depth with controlled drainage.
2-112 Chapter 2. Agriculture
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
4 Implementation Measures and Practices for
Cropland Edge-of-Field Trapping and Treatment
Edge-of-field practices remediate or intercept the pollutant before or after it is delivered to the
water resource if the pollutants have not been effectively controlled at the source or in the field.
Buffers and setbacks, soil amendments, wetlands, drainage water management, and controls in
animal agriculture are examples of important edge-of-field or end-of-pipe measures to prevent
nutrient loads to the Chesapeake Bay.
4.1 Buffers and Minimum Setbacks
Buffers are the areas between the cropland or other agricultural land use and the adjacent
waterbodies. Buffers are described in detail in Chapter 5 of this document.
Implementation Measure A-16:
Establish manure and chemical fertilizer application buffers or minimum setbacks
from in-field ditches, intermittent streams, tributaries, surface waters, open tile line
intake structures, sinkholes, agricultural well heads or other conduits to surface
waters.
Practice Effectiveness
Merriman et al. (2009) developed a compilation of BMP effectiveness results. Table 2-24
presents a listing of individual results for conservation buffer practices along with percent
reductions for TP, TN, and sediment. Additional data on reductions for particulate P, dissolved
P, NO3-N, and ammonium are also available in the document.
Liu et al. (2008) performed an extensive review of sediment trapping efficiencies from more than
80 representative BMP experiments. A summary of their data is presented in Table 2-25. Their
analysis of the data indicate that regardless of the area ratio of buffer to agricultural field, a 10-m
buffer and a 9 percent slope optimize the sediment-trapping capability of vegetated buffers.
Chapter 2. Agriculture 2-113
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
Table 2-24. TP, TN, and sediment reductions for various conservation buffer practices
Reference (as
cited by Merriman
etal. 1980
Binghamet al. 1980
Binghamet al. 1980
Udawatta et al. 2002
Udawatta et al. 2002
Meyer et al. 1999
Meyer et al. 1995
Sheridan etal. 1999
Sheridan etal. 1999
Sheridan 2005
Blanco-Canqui et al.
2004
Dillaha et al. 2004
Dillahaetal. 1988
Srivastava et al.
1996
Dillahaetal. 1996
Dillahaetal. 1988
Feagley et al. 1992
Chaubey etal. 1995
Sanderson et al.
2001
Chaubey etal. 2001
Chaubey etal. 1995
Daniels and Gilliam.
1996
Chaubey etal. 2004
Chaubey etal. 1995
Mendez et al. 2001
Mendez etal. 1999
Dillahaetal. 1989
Dillahaetal. 1989
Dillahaetal. 1988
Dillahaetal. 1989
Chaubey etal. 1995
Chaubey etal. 1995
State
NC
MO
MO
MO
MS
GA
GA
GA
GA
GA
MO
VA
AR
AR
VA
AR
TX
TX
TX
AR
MO
MO
AR
VA
VA
VA
VA
VA
VA
AR
AR
BMP name
Contour Buffer Strip (3 m)
Contour Buffer Strip (3 m)
Contour Buffer Strip (4.5 m)
Hedgerow Planting
Hedgerow Planting
Hedgerow Planting
Riparian Forest Buffer
Riparian Forest Buffer
Riparian Forest Buffer
Riparian Forest Buffer
Vegetated Filter Strip (VFS)
VFS
VFS
VFS
VFS
VFS
VFS (15.2m)
VFS (16.4m)
VFS (16.4m)
VFS (21. 4m)
VFS (3 m)
VFS (4 m)
VFS (4 m)
VFS (4 m)
VFS (4.3 m)
VFS (4.6 m)
VFS (4.6 m)
VFS (4.6 m)
VFS (4.6 m)
VFS (6 m)
VFS (6.1 m)
Field plot
Field plot
Field plot
Small
watershed
Field plot
Lab plot
Field
Field
Field
Farm
Farm
Field plot
Field plot
Field plot
Field plot
Field plot
Field plot
Field plot
Field plot
Field plot
Field
Field
Field plot
Field plot
Field plot
Field plot
Field plot
Field plot
Field plot
Field
Field
Field plot
3-8
3-8
3
3
3-8
3-8
3
0-3
0-3
0-3
3
3-8
3-8
3-8
8
8-15
N/A
3-8
N/A
N/A
3-8
3-8
3-8
3-8
N/A
3-8
8
15
15-25
3-8
3-8
3-8
B
B
B
D
D
C
B
N/A
N/A
N/A
D
D
C
C
C
C
D
C
C
C
C
B
D
C
N/A
C
C
C
C
C
B
C
TP%
52.77%
7.91%
26%
26%
56%
2%
65.5%
36%
63%
86.8%
47%
76%
91 .2%
55%
39.6%
50%
85%
73%
52%
49%
65%
58.4%
TN%
18.6%
14.53%
20%
20%
37%
1%
67.2%
43.9%
64%
75.7%
80.5%
40%
77%
39.2%
50%
55.6%
84%
73%
69%
47%
48%
53.5%
Total
sediment
19%
19%
76%
80%
95%
74%
68%
95%
31%
87%
78.49%
53%
91%
81.9%
83%
86%
76%
53%
68%
2-114
Chapter 2. Agriculture
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
Table 2-24. TP, TN, and sediment reductions for various conservation buffer practices (continued)
Reference (as
cited by Merriman
etal. 1980
Mendez etal. 1996
Coyne etal. 1999
Coyne etal. 1995
Dillahaetal. 1988
Dillahaetal. 1989
Dillahaetal. 1988
Dillahaetal. 1989
Dillahaetal. 1988
Dillahaetal. 1989
Chaubey etal. 1995
State
AR
VA
KY
VA
VA
VA
VA
VA
VA
AR
BMP name
VFS(6.1 m)
VFS (8.5 m)
VFS (9 m)
VFS (9.1m)
VFS (9.1m)
VFS (9.1m)
VFS (9.1m)
VFS (9.1m)
VFS (9.1m)
VFS (9.2 m)
Field plot
Field plot
Field plot
Field plot
Field plot
Field plot
Field plot
Field plot
Field plot
Field plot
Field plot
3-8
3-8
15
8
3-8
8
8-15
15
15-25
3-8
3-8
B
C
C
B
C
C
C
C
C
C
C
TP%
25.5%
19%
87
80%
93%
57%
65%
74%
TN%
21.4%
81.5%
9%
81%
80%
93%
72%
59%
66.6%
Total
sediment
90.2%
99%
58%
93%
95%
98%
88%
70%
Source: Merriman etal. 2009
Table 2-25. Summary of Vegetated Filter Strip (VFS) characteristics and corresponding sediment-
trapping efficiencies
Paper source
Young etal. (1980)
Hall etal. (1983)
Hayes and Hairston
(1983)
Dillahaetal. (1989)
Magette etal. (1989)
Partons etal. (1990)
Parsons etal. (1994)
Coyne etal. (1995)
Arora etal. (1996)
BMP
VFSt
VFS
VFS
VFS
VFS
VFS
VFS
VFS
VFS
VFS
VFS
VFS
VFS
VFS
VFS
VFS
VFS
VFS
VFS
VFS
VFS
VFS
Location
Pennsylvania
Mississippi
Virginia
Virginia
Virginia
Virginia
Virginia
Virginia
Maryland
Maryland
Maryland
Maryland
Maryland
Maryland
North Carolina
North Carolina
North Carolina
North Carolina
Kentucky
Iowa
Iowa
Buffer
width
4.06
6
2.6
9.1
4.6
9.1
4.6
9.1
4.6
9.2
4.6
9.2
4.6
9.2
4.6
4.3
8.5
4.3
8.5
4.6
20.12
20.12
Area
ratio
hi iffpr/nlnl
UUIlCl/UIUI
0.028
0.27
0.5
0.25
0.5
0.25
0.5
0.25
0.42
0.21
0.42
0.21
0.42
0.21
0.12
0.23
0.12
0.23
0.4
0.033
0.067
i
Slope
4
14
2.35
11
11
16
16
5
5
2.7
2.7
2.7
2.7
4.1
4.1
3.25
3.25
1.9
1.9
9
3
3
Sediment
trapping
efficacy
y
/o-
79
76
60
97.5
86
70.5
53.5
93
83.5
92.4
82.8
88.3
64.3
80.3
65.8
75
85
78
81
99
83.6
87.6
Mass
sediment
Inflow Outflow reduction
kn
y
35.37 6.4 28.97
0.000008 0.000002 0.000006
70.8 5.4 65.4
70.8 12.2 58.6
16.2 1.9 14.3
13.6 4.97 11.23
13.6 2.68 10.92
4.65 8.95
0.014 0.002 0.012
Chapter 2. Agriculture
2-115
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
Table 2-25. Summary of Vegetated Filter Strip (VFS) characteristics and corresponding sediment-
trapping efficiencies (continued)
Paper source
Daniels and Gilliam
(1996)
Robinson etal. (1996)
Van Dijketal. (1996)
Patty etal. (1997)
Barfield etal. (1998)
Coyne etal. (1998)
Tingle etal. 1998)
Munoz-Carpenaetal.
(1999)
Schmitt etal. (1999)
BMP
VFS
VFS
VFS
VFS
VFS
VFS
VFS
VFS
VFS
VFS
VFS
VFS
VFS
VFS
VFS
VFS
VFS
VFS
VFS
VFS
VFS
VFS
VFS
VFS
VFS
VFS
VFS
VFS
VFS
VFS
VFS
VFS
VFS
VFS
VFS
VFS
VFS
VFS
VFS
VFS
Location
North Carolina
North Carolina
North Carolina
North Carolina
Iowa
Iowa
Iowa
Iowa
Netherlands
Netherlands
Netherlands
Netherlands
Netherlands
Netherlands
Netherlands
Netherlands
Brittan, France
Brittan, France
Brittan, France
Brittan, France
Brittan, France
Brittan, France
Brittan, France
Brittan, France
Brittan, France
Kentucky
Kentucky
Kentucky
Kentucky
Kentucky
Kentucky
Mississippi
Mississippi
Mississippi
Mississippi
Mississippi
North Carolina
North Carolina
Nebraska
Nebraska
Buffer
width
m
3
6
3
6
3
3
9.1
9.1
1
4
5
10
5
10
5
10
6
12
18
6
12
18
6
12
18
4.57
9.14
13.72
9
4.5
9
0.5
1
2
3
4
4.3
8.5
7.5
15
Area
ratio
buffer/plot
0.034
0.071
0.034
0.071
0.05
0.05
0.15
0.15
0.12
0.24
0.36
0.12
0.24
0.36
0.12
0.24
0.36
0.21
0.41
0.62
0.41
0.24
0.67
0.018
0.045
0.09
0.14
0.18
0.11
0.22
0.093
0.19
Slope
4.9
4.9
2.1
2.1
7
12
12
7
5.2
5.2
2.3
2.3
2.5
2.5
8.5
8.5
7
7
7
10
10
10
15
15
10
9
9
9
9
9
9
3
3
3
3
3
6
6
6.5
6.5
Sediment
trapping
efficacy
%-
59
61
45
57
70
80
85
85
49.5
78.5
73
94
64.5
99
92
97.5
98.9
99
99.9
87
100
100
91
97
98
97
99.9
99.7
99
95
98
88
93
94
96
98
86
93
85
96
Inflow
493.2
493.2
493.2
20.4
20.4
20.4
309.16
309.16
309.16
258
212
361
0.018
0.036
0.072
0.108
0.144
64.76
54.88
3.99
3.01
Outflow
kn
K9
5.44
3.7
0.37
2.53
0
0
28.71
8.21
4.8
8.44
1.1
2.06
0.0022
0.0024
0.004
0.0048
0.0032
1.74
3.99
1.3
0.84
Mass
sediment
reduction
487.76
489.5
492.83
17.87
20.4
20.4
280.45
300.95
304.36
249.56
210.9
358.94
0.0158
0.0336
0.068
0.1032
0.1408
63.02
50.89
2.69
2.17
2-116
Chapter 2. Agriculture
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
Table 2-25. Summary of Vegetated Filter Strip (VFS) characteristics and corresponding sediment-
trapping efficiencies (continued)
Paper source
Sheridan etal. (1999)
Lee etal. (2000)
Abu-Zreig et al. (2004)
Blanco-Canquietal.
(2004)
Borin etal. (2005)
Helmers etal. (2005)
Gharabaghi etal. (2006)
Young etal. (1980)
Peterjohn and Correll
(1984)
Dillaha etal. (1988)
Dillha etal. (1989)
Fiener and Auerswald
(2003)
Fiener and Auerswald
(2005)
BMP
VFS
VFS
VFS
VFS
VFS
VFS
VFS
VFS
VFS
Riparian buffer
Riparian buffer
Riparian buffer
Riparian buffer
Riparian buffer
Riparian buffer
Riparian buffer
Riparian buffer
Riparian buffer
Riparian buffer
Riparian buffer
Riparian buffer
Grassed
waterways
Grassed
waterways
Grassed
waterways
Location
Georgia
Iowa
Canada
Canada
Columbia,
Missouri
Northeast Italy
Nebraska
Ontario,
Canada
Ontario,
Canada
Maryland
Maryland
Munich
Munich
Central Europe
Buffer Area
width ratio
mhi iffpr/nlnt
UUIlCl/UIUL
8 0.03
7.1 0.32
2 0.2
15 0.025
8 0.09
6
13 0.06
2.5
20
21.3
27.4
19
60
4.6
4.6
9.1
9.1
4.6
4.6
9.1
9.1
35 0.16
17.5 0.12
18.5 0.076
Slope
2.5
5
2.3
2.3
5
1.8
1
4
4
5
5
11
16
11
16
11
16
11
16
9.3
9
3.6
Sediment
trapping
efficacy
%-
81
70
68
98
90
94
80
50
98
78
79
90
94
87
76
95
88
86
53
98
70
97
77
93
Inflow
2.82
5887
9324
1.6*10-8
3450
147
3.99
o.no-6
2.3*1 0-7
2*io-7
4.5*10-7
330.72
175.74
Outflow
kn
Kg
0.85
1876
219
1.3*10-10
200
29
1.3
0.2*1 0-7
1.1*10-7
o.no-7
1.4*10-7
7.42
40.02
Mass
sediment
reduction
1.97
4011
9105
1.58*10-8
3250
118
2.69
0.8*1 0-7
1.2*10-7
1.9*10-7
3.1*10-7
323.3
135.72
t VFS represents vegetated filter strips.
Source: Liu etal. 2008
Ghadiri et al. (2001) developed a set of laboratory experiments with a tilting flume to investigate
the effects of buffer strips on flow hydrology and sediment transport/deposition in and around
the strips. The investigators found that flow retardation initiates above the strip and can begin to
remove sediment. The results summarized in Table 2-26 show sediment deposition ranging
from 18 to 77 percent, but caution is advised when applying those laboratory results to field
conditions. In a study of simulated filter strips, Jin et al. (2002) found that adding a mulch barrier
increased the sediment trapping efficiency of filter strips by 10-60 percent compared with the
Chapter 2. Agriculture
2-117
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
same flow, slope, and filter strip conditions without mulch. The observed interactions of crop
residue mulches and filter strips suggest that combining residue management systems with
vegetative buffer strips containing an upslope edge of strong vegetation offer potential synergies
for increased conservation effectiveness. Jin and Romkens (2001) found that over 80 percent of
the sediment trapped by a vegetative (or vegetated) filter strip (VFS) was deposited in the
approach channel to the VFS and in the upper half of the VFS. As the slope increased,
deposition moved downstream and deposited sediment became larger.
Table 2-26. Effect of high-density grass strip on sediment concentration on different slopes
Slope
(%)
1.5
2.0
3.4
5.2
Sediment concentration
(9/L)
Unaffected
flow
1.25
4.30
17.44
78.63
In the
backwater
1.02
3.11
10.76
18.15
After grass
strip
1.06
3.20
11.01
16.81
Sediment deposited
(%)
In the
backwater
18
28
38
77
Inside grass
strip
-4
+ 3
-2
+ 7
Source: Ghadiri et al. 2001
In a field experiment in Ontario, Gharabaghi et al. (2001) compared sediment removal efficiency
using a variety of filter widths (2.44, 4.88, 9.67 and 19.52 m), flow rates, and slopes. They found
that sediment removal ranged from 50 to 98 percent and generally found little improvement for
widths greater than 10m. Sediment removals are depicted in Figure 2-6.
Fig. 1 : Average Sediment Removal Efficiency of Vegetative Filter Strips
(U
Q.
53
0!
IT
0 S 10 IS
Flow Path Length, i.e. Width of the VFS (m)
Source: Gharabaghi et al. 2001
Figure 2-6. Average sediment-removal efficiency of VFS.
2-118
Chapter 2. Agriculture
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
In a Raritan Basin (New Jersey) case study, Qiu et al. (2009) compared the placement of fixed-
width buffers using regulatory rules, variable-width buffers according to watershed initiatives,
and variable source area-based conservation buffer placement strategy derived from an
alternative concept of watershed hydrology. The authors showed that there is little difference in
cost-effectiveness between fixed- and variable-width buffers but that the variable source area-
based buffer placement strategy, which targets the most hydrologically critical source areas in a
watershed tier buffer placement, is more cost-effective.
In a riparian buffer in Connecticut, one-half of a 35 m by 250 m riparian buffer cropped in corn
was seeded with fine-leaf fescue and allowed to remain idle (Clausen et al. 2000). TKN and TP
concentrations significantly (P less than 0.05) increased as groundwater flowed through the
restored buffer, while NO3 concentrations declined significantly with most (52 percent) of the
decrease occurring within a 2.5-m wetland adjacent to the stream. An N mass balance for the
2.5-m strip indicated that denitrification accounted for only one percent of the N losses and plant
uptake accounted for 7-13 percent of the N losses annually. Groundwater was the dominant
source of N to the buffer and also the dominant loss pathway. Restoring the riparian buffer
decreased (p less than 0.05) overland flow concentrations of TKN by 70 percent, NO3-N by
83 percent, TP by 73 percent, and TSS by 92 percent as compared with the control. Restoration
reduced (P less than 0.05) NO3-N concentrations in groundwater by 35 percent as compared
with the control. Underestimated denitrification and dilution by upwelling groundwater in the
wetland area adjacent to the stream were believed to be primarily responsible for the lower
NO3-N concentrations observed.
In a plot study, Dosskey et al. (2007) examined whether filter strip effectiveness changes over
time and if temporal change depends on vegetation type. Plots containing all-grass (New Grass)
and grass with trees and shrubs (New Forest) were established in 1995 among plots that
contained either grass since 1970 (Old Grass) or were recultivated and replanted annually with
grain sorghum (Crop). Once each summer, in 1995, 1996, 1997, 2003, and 2004, identically
prepared solutions containing sediment, N and P fertilizer, and bromide tracer were applied to
the upper end of each plot during a simulated rainfall event. The authors concluded that filter
strip performance improves over time, with most of the change occurring within three growing
seasons after establishment. Infiltration characteristics account for most of that change, and
grass and forest vegetation are equally effective as filter strips for at least 10 growing seasons
after establishment.
Lee et al. (2003) used a field plot study to determine the effectiveness of an established multi-
species buffer in trapping sediment, N, and P from cropland runoff during natural rainfall events.
A switchgrass buffer removed 95 percent of the sediment, 80 percent of the N, 62 percent of the
NO3-N, 78 percent of the P, and 58 percent of the phosphate-phosphorus (PO4-P), while a
switchgrass/woody buffer removed 97 percent of the sediment, 94 percent of the TN, 85 percent
Chapter 2. Agriculture 2-119
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
of the NO3-N, 91 percent of the TP, and 80 percent of the PO4-P in the runoff. In an earlier study
using the same plots, Lee et al. (2000) found generally similar results; during a 2-hour rainfall
simulation at 25 mm/h, the switchgrass buffer removed 64, 61, 72, and 44 percent of the
incoming TN, NO3-N, TP, and PO4-P, respectively. The switchgrass-woody buffer removed 80,
92, 93, and 85 percent of the incoming TN, NO3-N, TP, and PO4-P, respectively. During a
1-hour rainfall simulation at 69 mm/h, the switchgrass buffer removed 50, 41, 46, and 28
percent of the incoming TN, NO3-N, TP, and PO4-P, respectively, The switchgrass-woody plant
buffer removed 73, 68, 81, and 35 percent of the incoming TN, NO3-N, TP, and PO4-P,
respectively. In both studies, the switchgrass buffer was effective in trapping coarse sediment
and sediment-bound nutrients, but the additional buffer width with high infiltration capacity
provided by the deep-rooted woody plant zone was effective in trapping the clay and soluble
nutrients.
Using a set of 36 field lysimeters with six different ground covers (bare ground, orchardgrass,
tall fescue, smooth bromegrass, timothy, and switchgrass), Lin et al. (2007) evaluated the ability
of grasses to reduce nutrient levels in soils and shallow groundwater. The leachate from each
lysimeter was collected after major rainfall events during a 25-day period, and soil was collected
from each lysimeter at the end of the 25-day period. Grass treatments reduced NO3-N levels in
leachate by 74.5 to 99.7 percent compared to the bare ground control, but timothy was
significantly less effective at reducing NO3-N leaching than the other grasses. Switchgrass
decreased PO4-P leaching to the greatest extent, reducing it by 60.0 to 74.2 percent compared
to the control. In a separate study, Bedard-Haughn et al. (2005) found that cutting vegetative
buffers increased the uptake of NO3-N 2.3 times that of uncut buffers.
The influence of vegetation characteristics, buffer width, slope, and stubble height on sediment
retention was evaluated in a Montana study using three vegetation types (sedge wetland, rush
transition, bunchgrass upland) on plots spanning 2 to 20 percent slopes (Hook 2003). Sediment
retention was affected strongly by buffer width and moderately by vegetation type and slope, but
it was not affected by stubble height. Mean sediment retention ranged from 63 to greater than
99 percent for different combinations of buffer width and vegetation type, with 94 to 99 percent
retention in 6-m-wide buffers regardless of vegetation type or slope. Results suggest that
rangeland riparian buffers should be at least 6 m wide, with dense vegetation, to be effective
and reliable.
Mankin et al. (2007) studied the effectiveness of established grass-shrub riparian buffer systems
in reducing TSS, P, and N using simulated runoff on nine plots with buffer widths ranging from
8.3 to 16.1 m. Vegetation types were all natural selection grasses (control), a 2-segment buffer
with native grasses and plum shrub, and a 2-segment buffer with natural selection grasses and
plum shrub. Removal efficiencies were strongly linked to infiltration, with TSS mass and
concentration reductions averaging 99.7 percent and 97.9 percent, TP reductions of
2-120 Chapter 2. Agriculture
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
91.8 percent and 42.9 percent, and TN reductions at 92.1 percent and 44.4 percent. Mankin et
al. (2007) concluded that adequately designed and implemented grass-shrub buffers with widths
of 8 m provide for water quality improvement, particularly if adequate infiltration is achieved.
Hoffman et al. (2009) examined the main hydrological pathways for P losses from and P
retention in riparian buffers. They determined that P retention rates of up to 128 kg P/ha-yr can
be accounted for by sedimentation, while plant uptake can temporarily immobilize up to 15 kg
P/ha-yr. Dissolved P retention is often below 0.5 kg P/ha-yr, and the authors note that several
studies have shown significant release of dissolved P up to 8 kg P/ha-yr.
In Finland, the effects of 10-m-wide, annually cut grass buffer zones and vegetated buffer
zones under natural vegetation were compared on 70-m-long by 18-m-wide plots with no buffer
zone (Uusi-Kamppa 2006). Retention of TS, TP, and PP was greater than 50, 40, and greater
than 45 percent, respectively, for both treatments.
In northeast Italy, a 5-m-wide grass strip and a 1-m-wide row of trees were evaluated with corn
and wheat from 1997 to 1999 (Borin and Bigon 2002). Under a variety of fertilization levels and
tree sizes, water discharged from the strip was always below 2 mg/L NO3-N. Tree size showed
no evident effect on the reduction of the concentration. In a companion study from 1998 to
2001, Borin et al. (2005) evaluated 6-m buffer strips with adjoining fields of corn-wheat-
soybeans. The buffer strip was composed of two rows of regularly alternating trees and shrubs,
with grass in the inter-rows. Total runoff was reduced by 78 percent. TSS concentrations at the
control was 2-7 times greater than the TSS of 0.14 mg/L from the buffer strip. N concentrations
through the buffer strip were higher than control, but mass export was reduced from 17.3 to
4.5 kg/ha.
Practice Costs
Contour buffer strips cost about $270/ac in Virginia, and typical total costs are about $2,700
(USDA-NRCS 2010). Filter strips cost about $262 and $322 per acre for warm-season and cool-
season grasses, respectively. Total costs are typically $524 for warm-season grasses and $645
for cool-season grasses.
Field borders using grasses cost about $210/ac for warm-season grasses and $330/ac for cool-
season grasses, with typical total costs of about $420 and $650, respectively (USDA-NRCS
2010). Various mixtures of peas, mixed shrubs, and Indian grass cost about $300/ac to $400/ac,
with total costs of $600 to $800. High-end mixtures including wildflowers can cost $1,300/ac, for
a typical total cost of about $2,600. Hedgerow planting with hardwoods costs are approximately
$910/ac ($455 total), whereas hedgerow planting with mixed shrub seedlings can range from
Chapter 2. Agriculture 2-121
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
$951 to $1,419 per acre ($476 to $709 total cost) depending on the shrubs used (USDA-NRCS
2010).
Riparian forest buffers incorporating hardwoods generally cost around $900 to $1500 per acre
in Virginia, with typical total costs ranging from $6,400 to $10,600 (USDA-NRCS 2010).
4.2 Soil Amendment
Implementation Measure A-17:
Treat buffer or riparian soils with alum, WTR, gypsum, or other materials to adsorb
P before field runoff enters receiving waters.
It has been widely observed that adding materials like alum, alum-based residuals, gypsum, and
other materials to soils can be effective in reducing water-soluble P concentrations in manure-
treated soils. Some researchers have evaluated the ability of such soil amendment—either as
area-wide applications or as buffer strips—to reduce or intercept nutrient runoff before delivery
from upland fields into adjacent waterways.
Gallimore et al. (1999) reported that dissolved P in runoff was reduced by 46 percent by a buffer
strip treated with WTR on the lower 25 percent of plots. Soluble NH4-N was also reduced
significantly. Dayton and Basta (2005b) found that adding alum-based residuals to soils as an
enhanced buffer strip reduced mean dissolved P in runoff water by 3-38 percent for a 5 Mg/ha
application, by 25-50 percent for a 10 Mg/ha addition, and by 67-86 percent for a 20 Mg/ha
addition.
DeWolfe (2006) reported that surface application of WTR to soils (previously amended with
poultry litter) at 10 Mg/ha decreased runoff P from 53-69 percent; application at 20 Mg/ha
decreased runoff P from 68-87 percent. Penn and Bryant (2006) tested several sorbing
materials including alum, gypsum, and fly ash to reduce P losses from streamside cattle loafing
areas. All amendments reduced runoff dissolved P concentrations initially—alum (98-99
percent), WTR (81 percent), gypsum (74-88 percent) and fly ash (60 percent); however, after
28 days, runoff P concentrations were not significantly different from untreated plots.
Promising research is underway on using materials such as gypsum (Feyeriesen et al. 2008)
and steel slag (Weber et al. 2007) for sorption of P in field runoff.
2-122 Chapter 2. Agriculture
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
4.3 Wetlands
Implementation Measure A-18:
Restore wetlands and riparian areas from adverse effects. Maintain nonpoint source
abatement function while protecting other existing functions of the wetlands and
riparian areas such as vegetative composition and cover, hydrology of surface water
and groundwater, geochemistry of the substrate, and species composition.
Properly functioning natural wetlands and riparian areas (discussed in Chapter 5) can
significantly reduce nonpoint source pollution by intercepting surface runoff and subsurface flow
and by settling, filtering, or storing sediment and associated pollutants. Wetlands and riparian
areas typically occur as natural buffers between uplands and adjacent waterbodies. Loss of
natural wetlands and riparian areas allows a more direct contribution of nonpoint source
pollutants to receiving waters. Degraded wetlands and riparian areas can even become
pollutant sources. Thus, natural wetlands and riparian areas should be protected and should not
be used as designated erosion control practices. Their nonpoint source control functions are
most effective as part of an integrated land management system focusing on nutrient, sediment,
and erosion control practices applied to upland areas.
Protection of the full range of functions for wetlands and riparian areas are discussed in National
Management Measures to Protect and Restore Wetlands and Riparian Areas for the Abatement
of Nonpoint Source Pollution (USEPA 2005). Protection of wetlands and riparian areas should
allow for both nonpoint source pollution control and maintenance of other benefits of other
ecosystem services such as wildlife habitat, flood mitigation, and water storage.
The following practices can protect wetlands and riparian areas:
• Identify existing functions of those wetlands and riparian areas with significant nonpoint
source control potential when implementing management practices.
• Do not alter wetlands or riparian areas to improve their water quality functions at the
expense of their other functions.
• Use appropriate preliminary treatment practices such as erosion control, vegetated
treatment systems or detention, or retention basins to prevent adverse effects on
wetland functions that affect nonpoint source pollutant abatement from hydrologic
changes, sedimentation, or contaminants.
Wetlands and Acreman (2004) gathered data from 57 wetlands from around the world to
evaluate nutrient removal efficacy. Table 2-27 displays a list of those wetlands, and Figure 2-7
Chapter 2. Agriculture 2-123
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
displays the removal efficiencies for N and phosphorous as a function of loading. The
correlation for N is statistically significant while the regression line for P is not.
Table 2-27. Summary of wetlands evaluated
Summary of references studied showing wetland name, wetland type and country of location. References are split into those
showing an increase in nutrient loading, decrease in nutrient loading and those showing no change.
Author(s)
Date
NorP
Wetland name
Wetland type
Country
Nutrient Retention
Raisin and Mitchell
Raisin and Mitchell
Jacobs and Gilliam
Cooper and Gilliam
Lowrance et al.
Cooke
Bugenyi
Patruno and Russell
Baker and Maltby
Peterjohn and Correll
Jordan et al.
Gehrels and
Mulamootth
Burt el al.
Haycock and Burt
Cooper
Prior
Haycock and Pinay
Chauvelon
Maltby et al.
Osborne and Totome
Cooper
Lindkvist and
Hakansson
Lindkvist
Mander et al.
Nunez Delgado et al.
Mander et al.
Downes et al.
Brinson et al.
Brunet
Tilton and Kadlec
Burke
Boyt et al.
Spangler
Yonika and Lowry
1995
1995
1985
1987
1984
1994
1993
1994
1995
1984
1993
1989
1998
1993
1994
1998
1993
1998
1995
1994
1990
1993
1992
1991
1997
1997
1997
1984
1994
1979
1975
1977
1977
1979
TPN
TP
NO3
P
NO3
P, NO3
N, P
N, P
NO3, NO4
SOlP
NO3, TP
TP
NO3
N03
NO3
N, P
N03
N, P
N
TP, SRP, NH4
N03
TP
TP
TP
N03
N, P
NO3
N, P
PN
N, P
N, P
P
P
N
Humphrey's wetland
Reid's wetland
Unknown
Unknown
Unknown
Unknown
Unknown
Yamba wetland
Kismeldon Meadows and
Bradford Mill
Rhode River drainage basin
Chester River catchment
Unknown
R. Leach floodplain
R. Leach floodplain
Unknown
R. Lambourn floodplain
R. Leach floodplain
Rhone river delta
Floodplains in Devon
Waigani
Scotsman Valley, NZ
Unknown
Unknown
Unknown
Unknown
Porijogi River catchment
Whangamata Stream
Tar River floodplain
Adour River floodplain
Unknown
Unknown
Unknown
Unknown
Unknown
Mash/swamp
Mash/swamp
Riparian
Riparian
Riparian
Mash/swamp
Riparian
Marsh/swamp
Riparian
Riparian
Floodplain
Marsh/swamp
Floodplain
Floodplain
Swamp
Floodplain
Riparian
Riverine delta
Floodplain
Marsh/swamp
Riparian
Unknown
Unknown
Various
Riparian
Riparian
Riparian
Riparian
Floodplain
Fen
Peat land
Marsh/swamp
Marsh/swamp
Marsh/swamp
Australia
Australia
USA
USA
USA
New Zealand
Uganda
Australia
UK
USA
USA
USA
UK
UK
NZ
UK
UK
France
UK
Papua N. Guinea
New Zealand
Sweden
Sweden
Estonia
Spain
Estonia
New Zealand
USA
France
USA
Ireland
USA
USA
USA
2-124
Chapter 2. Agriculture
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
Table 2-27. Summary of wetlands evaluated (continued)
Author(s)
Semkin et a/.
Semkin et al.
Johnston et al.
Johnston et al.
Pinay and Decamps
Jordon et al.
Mwanuzi et al.
Rzepecki
Zhang et al.
Bratli et al.
Kellog and Bridgeham
Kansiime and Nalubega
Kansiime and Nalubega
Chescheir et al.
Dorge
Dorge
Dorge
Schlosser and Karr
Hanson et al.
Schwer and Clausen
Daniels and Gilliam
Date
1976
1976
1984
1984
1988
2003
2003
2002
2000
1999
2003
1999
1999
1991
1994
1994
1994
1981
1994
1989
1996
NorP
N, P
N, P
N, P
N, P
N
TN, TP
P04
SOlP
TN, TP
N, P
P04
N
N
TP, NO3
N03
N03
NO3
TP
N03
TP, TN
N, P
Wetland name
Unknown
Unknown
nr White Clay Lake
nr White Clay Lake
Garonne Valley
Kent Island
Unknown
Unknown
Unknown
Unknown
Unknown
Unknown
Unknown
Unknown
Rabis Baek
Syvbaek
Glumso
Champaign-Urbana
nr Kingston
nr Charlotte
Cecil soil area
Wetland type
Marsh/swamp
Marsh/swamp
Marsh/swamp
Riparian
Riparian
Marsh/swamp
Riparian
Riparian
Marsh/swamp
Marsh/swamp
Peat land
Marsh/swamp
Marsh/swamp
Riparian
Peat land
Riparian
Marsh/swamp
Riparian
Riparian
Riparian
Riparian
Country
USA
USA
USA
USA
France
USA
Tanzania
Poland
USA
Norway
USA
Uganda
Uganda
USA
Denmark
Denmark
Denmark
USA
USA
USA
USA
Nutrient Addition
Cook
Peterjohn and Correll
Jordan et al.
Mulamootth
Prior
Osborne and Totome
Downes et al.
Clausen et al.
Daniels and Gilliam
1994
1984
1993
1989
1998
1994
1997
1993
1996
N03
SOlP
N, P
SOlP
TON, TOP
NO2, NO3
NO3, SRP
TN
N, P
Unknown
Unknown
Chester River catchment
Unknown
R. Lambourne floodplain
Waigani
Whangamata Stream
Unknown
Georgeville soil area
Riparian
Floodplain
Marsh/swamp
Floodplain
Marsh/swamp
Riparian
Riparian
Riparian
New Zealand
USA
USA
USA
UK
Papua N. Guinea
New Zealand
USA
USA
No Nutrient Retention/Addition
Raisin and Mitchell
Kadlec
Elder
Ontkean et al.
Daniels and Gilliam
1995
1985
1985
2003
1996
TPN
P
N
N, P
TP, PO4
Reid's wetland
Unknown
Apalachicola River floodplain
Hilton Wetland
Georgeville soil area
Marsh/swamp
Marsh/swamp
Floodplain
Pond
Riparian
Australia
USA
USA
Canada
USA
Source: Adapted from Fisher and Acreman 2004
Notes: N = several N species, P = several P species, TP = total phosphorus, TN = total or Kjeldahl N, sol = soluble N or P,
SRP = soluble reactive P, TPN = total particulate N, PN = particulate N, PO4 = orthophosphate, NO3 = nitrate, NO2 = nitrate
and NH4 = ammonium, including ammonium-N.
Chapter 2. Agriculture
2-125
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
100
90
80
70
60
50
40
30
20
10
0
ff = 0.3534
1 10 100 1000 10000
N loading to weland (Iog0) (kg ha'1 y ')
100
90
80
70
60
50
40
30
20
10
0
R2 = 0.0503
10
100
1000
10000
P loading to wetland (Iog0) (kg ha y
Fig. 4. Relationship between nutrient reduction within wetlands and the amount of a) N loading to wetlands and b) P loading to wetlands
reported in a study, (t - TN, O - nitrate and x = several ;V species and
b) F loading to wetlands, • -TP, D - onhophosphate and 4 - several P species).
Source: Fisher and Acreman 2004
Figure 2-7. Percent nutrient reduction as a function of loading.
On Kent Island, Maryland, a 1.3-ha restored wetland received the unregulated inflows from a
14-ha agricultural watershed (Jordan et al. 2003), and the ability of the wetland to remove
nutrients was examined over 2 years after its restoration. Most nutrient removal occurred in the
first year, which included a 3-month period of decreasing water level in the wetland. In that year,
the wetland removed 59 percent of the TP, 38 percent of the TN, and 41 percent of the TOC it
received. However, in the second year, which lacked a drying period, there was no significant (P
greater than 0.05) net removal of TN or P, although 30 percent of the TOC input was removed.
For the entire 2-year period, the wetland removed 25 percent of the ammonium, 52 percent of
the NO3, and 34 percent of the organic carbon it received, but there was no significant net
removal of TSS or other forms of N and P.
A wetland mesocosm experiment was conducted in eastern North Carolina to determine if
organic matter (OM) addition to soils used for in-stream constructed wetlands would increase
NO3-N treatment (Burchell et al. 2007). Four batch studies, with initial NO3-N concentrations
ranging from 30 to 120 mg/L, were conducted in 2002 in 21 surface-flow wetland mesocosms.
The results indicated that increasing the OM content of a Cape Fear loam soil from 50 g/kg to
110 g/kg enhanced NO3-N wetland treatment efficiency in spring and summer batch studies, but
increases to 160 g/kg OM did not. Increased OM addition and biosolids to the Cape Fear loam
significantly increased biomass growth in the second growing season when compared to no OM
addition. Those findings indicate that increased OM in the substrate will reduce the area
required for in-stream constructed wetlands to treat drainage water in humid regions.
A small-scale wetland system was constructed and monitored for several years to quantify
nutrient removal near Steamboat Creek, a tributary of the Truckee River in Nevada (Chavan et
al. 2007). Results indicated seasonal variations in nutrient removal with 40-75 percent of TN
2-126
Chapter 2. Agriculture
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
and 30-60 percent of TP being removed, with highest removals during summer and lowest
removals during winter. In a following study to evaluate the effectiveness of a large-scale
wetland, 10 parallel pilot-scale wetland mesocosms were used to test the effects of drying and
rewetting, hydraulic retention time (HRT), and high N loading on the efficiency of nutrient and
TSS removal (Chavan et al. 2008). During increased influent N loading (9.5 +/- 2.4 mg/L),
manipulated mesocosms functioned as sinks for TN with removal efficiency increasing from
45 +/-13 percent to 87 +/- 9 percent. The average change in TN concentration was 9.1 +/- 2.2
mg/L. TP removal was associated with TSS removal.
Wetlands dominated by submerged aquatic vegetations (SAVs) can take up nutrients,
particularly P, from surface flow with high efficiency. In a 1999-2001 study in South Florida,
samples were collected from four small constructed test cells (wetlands) (Gu 2008). Test cells
receiving higher TP (average = 75 ug/L) displayed a removal efficiency of 60 percent while test
cells receiving lower TP (average = 23 ug/L) had a 20 percent removal efficiency. In a similar
study, Gu and Dreschel (2008) evaluated the effectiveness of constructed wetlands from
2002-2004. Test cells receiving higher TP (average = 72 ug/L) displayed a removal efficiency of
56-65 percent while test cells receiving lower TP (average = 43 ug/L) had a 35-62 percent
removal efficiency with a hydraulic loading rate of 9.27 in/yr.
The restoration plan for the Everglades includes construction of large stormwater treatment
areas (STAs) to intercept and treat relatively high nutrient water down to very low TP
concentrations (White et al. 2006). One such STA has been in operation for approximately
10 years and contains both emergent aquatic vegetation (EAV) and SAV communities. The
authors investigated the interaction of vegetation type (EAV or SAV) and hydrology
(continuously flooded or periodic drawdown) on the P removal capacity in mesocosms packed
with peat soil obtained from the STA. The surface water had low TP concentrations with an
annual mean of 23 ug/L. For SRP and TP, hydrologic fluctuations had no discernable effect on
P treatment while vegetation type showed a significant effect. Influent SRP decreased by
49 percent for the SAV treatments compared with 41 percent for the EAV treatments,
irrespective of hydrology treatment. The reduction of dissolved organic P was also higher for the
SAV treatment, averaging 33 percent, while showing a reduction of 11 percent for the EAV
treatments. There was no significant difference in the treatment efficiency of particulate P
across the treatments. The SAV treatments removed 45 percent of TP while EAV removed
significantly less at 34 percent of TP. By mass calculations, the EAV required 85 percent more
P for plant growth than was removed from the water column in one year compared with only
47 percent for the SAV. Therefore, the EAV mined substantially more P from the relatively
stable peat soil, translocating it into the detrital pool.
In an examination of benefits to water quality provided by a natural, flow-through wetland and a
degraded, channelized wetland within the flood-irrigation agricultural landscape of the Sierra
Chapter 2. Agriculture 2-127
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
Nevada foothills of northern California, Knox et al. (2008) found that the nondegraded, reference
wetland significantly improved water quality by reducing loads of TSS, NO3, and E. coli on
average by 77, 60, and 68 percent, respectively. Retention of TN, TP, and SRP was between
35 and 42 percent of loads entering the reference wetland. Retention of pollutant loads by the
channelized wetland was significantly lower than by the reference wetland for all pollutants
except SRP. A net export of sediment and NO3 was observed from the channelized wetland.
Decreased irrigation inflow rates significantly improved retention efficiencies for NO3, E. coli,
and sediments in the reference wetland. It is suggested that maintaining such natural wetlands
and regulating inflow rates can be important aspects of a BMP to improve water quality in runoff
from irrigated pastures.
Practice Costs
Wetland enhancements costs in Virginia include $0.47/ft2 ($2,575 typical total cost) for
excavated seasonal pools in hydric soil sites, $0.026/ft2 ($145 total) for broadcasting a wetland
plant seed mixture, and $0.98/ac ($5,370 total) for wetland plant plugs (USDA-NRCS 2010).
4.4 Drainage Water Management
Subsurface drainage is a water management practice that is commonly used on many highly
productive fields in areas such as the Atlantic Coastal Plain and the Midwest, but because NO3
carried in drainage water contributes to water quality problems in the Chesapeake Bay (as well
as some other waterbodies such as the Gulf of Mexico), strategies are needed to reduce the
NO3 loads while maintaining adequate drainage for crop production (Frankenberger et al. 2006).
Drainage is generally achieved with open ditches or buried pipe accompanied by either gravity-
based or pumped outlets. Practices that can reduce NO3 loads on tile-drained soils include the
following (Frankenberger et al. 2006):
• Fine-tuned fertilizer application rates and timing
• Winter forage or cover crops
• Controlled drainage and water table management
• Ditch management
• Bioreactors to treat drainage water
• Constructed wetlands
Fertilizer management and cover crops are addressed in this document in Sections 2.1 and 3.3
respectively, whereas the other practices are addressed here. In addition, irrigation tailwater
recovery systems are not included in this document.
2-128 Chapter 2. Agriculture
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
Controlled drainage is the control of surface and subsurface water through use of drainage
facilities and water control structures. Water table management is any combination of
management, control, or regulation of soil-water conditions in the profile of agricultural soils
through the use of water management structures (e.g., subsurface drains, water control
structures, and water conveyance facilities) and strategies designed specifically for the given
site conditions (Brown 1997) (NRCS Practice Code 554). Graded ditches are used to collect or
intercept excess surface or subsurface water and convey it to an outlet (USDA-NRCS 2008).
Ditch management includes managing cleanouts and vegetation within the ditch. Bioreactors
are one form of edge-of-field treatment of drainage water in which the drainage is diverted into a
trench filled with wood chips (Minnesota Department of Agriculture No date). Constructed
wetlands are constructed, shallow, earthen impoundments containing hydrophytic vegetation
designed to treat both point and nonpoint sources of water (USDA-NRCS 2002).
In drainage water management, a water control structure in a main, sub-main, or lateral drain is
used to manipulate the depth of the drainage outlet (Frankenberger et al. 2006). The water table
must rise above the outlet depth for drainage to occur, as illustrated in Figure 2-8. The outlet
depth, as determined by the control structure, is
• Raised after harvest to limit drainage outflow and reduce the delivery of NO3 to ditches
and streams during the off-season (1 in Figure 2-8)
• Lowered in early spring and again in the fall so the drain can flow freely before field
operations such as planting or harvest (2 in Figure 2-8)
• Raised again after planting and spring field operations to create a potential to store water
for the crop to use in midsummer (3 in Figure 2-8)
Source: Frankenberger et al. 2006; used with permission
Figure 2-8. Drainage control structure.
Chapter 2. Agriculture
2-129
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
Implementation Measure A-19:
For both new and existing surface (ditch) and subsurface (pipe) drainage systems,
use controlled drainage, ditch management, and bioreactors as necessary to
minimize off-farm transport of nutrients.
Practice Effectiveness
Controlled drainage and water table management practice effectiveness
Numerous studies of the effects of controlled drainage have been conducted in North Carolina,
the Midwest, and Canada (Table 2-28). The studies have shown that controlled drainage can
significantly reduce discharge volume and NO3 concentrations.
Table 2-28. Measured effectiveness of controlled drainage
Location
North
Carolina
North
Carolina
Illinois
Ohio
Ontario,
Canada
Ontario,
Canada
Ontario,
Canada
Ontario,
Canada
Ontario,
Canada
Ontario,
Canada
Soils and crops
Moderately well
drained soils
Poorly drained
soils
Corn-soybean,
poorly drained
Corn
Corn
Corn
Corn, soybeans
Sandy loam
Clay loam
Study
type
Field
Field
Field
Plot
Field
Field
Plot
Plot
Field
Plot
Practice
CD-
flashboar
d riser
CD-
flashboar
d riser
CD
CD
CDS
CDS-CT
CDS
CDS
CDS
CDS
Reference
practice
UD
UD
UD
UD
UD
UD-MP
UD
UD
UD
UD
Reduction vs. reference practice
Discharge
85%
50%
40%
24%
-8%
36%
0%
50%
NO3-N
cone.
25%d
41%d
14%d
38%d
32%
NO3-N
load
85%a
50%b
< 47%c
45%
43%
49%
36%
27%e
37%
66%
Source
Gilliam et al.
1979
Gilliam et al.
1979
Kalita et al.
2007
Fausey 2005
Drury et al.
1996
Drury et al.
1996
Ng et al.
2001
Tan et al.
2003
Tan et al.
2004
2-130
Chapter 2. Agriculture
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
Table 2-28. Measured effectiveness of controlled drainage (continued)
Location
Ontario,
Canada
Ontario,
Canada
North
Carolina
Various
Various
Soils and crops
Corn (150 kg
N/ha)-soybean
(no N), clay loam
Corn (200 kg
N/ha)-soybean
(50 kg N/ha), clay
loam
Corn (150 kg
N/ha)-soybean
(no N), clay loam
Corn (200 kg
N/ha)-soybean
(50 kg N/ha), clay
loam
Silt loam, Corn-
soybean strip-
cropping
Various
Various
Various
Study
type
Field
Field
Field
Field
Field
RevieW
RevieW
RevieW
Practice
CD
CD
CDS
CDS
CDS -.05
m
CDS-
.075m
CD
CD
CD
Reference
practice
UD
UD
UD
UD
UD
UD
UD
UD
UD
Reduction vs. reference practice
Discharge
-555% to
58%g'h
-583% to -
70%g'h
30%kJ
17%-85%
NO3-N
cone.
61%-
84%g
52%-
77%g
<20%''m
NO3-N
load
44%f
31 %f
66%f
68%f
0%-94%gj
0%-30%gj
45%''"
50%
18%-85%
Source
Drury et al.
2009
Drury et al.
2009
Mejia and
Mandramoot
oo 1998
Evans et al.
1996
Appelboom
and Fouss
2006
Skaggs and
Youssef 2008
KEY: CD = controlled drainage, UD = Uncontrolled or traditional or free-tile drainage, CDS = controlled drainage-
subirrigation, CDS-CT = controlled drainage-subirrigation with conservation tillage, UD-MP = Uncontrolled or traditional
drainage with moldboard plowing.
Notes:
a. Load reduction due solely to discharge reduction; no change in NOs-N concentration.
b. Reductions due to increased penetration to deeper soil horizons where denitrification occurred.
c. NOs load reductions due mostly to discharge reductions. Phosphate load reductions of up to 83%
d. Flow-weighted mean
e. Also reduced dissolved organic (47%) and dissolved inorganic (54%) P loads
f. TN
g. Monitoring only during growing season (April/May-November).
h. Increased discharge due to lack of management, subirrigation, and high rainfall, resulting in little storage for rainfall under
CDS.
i. No significant difference in 1995 (0%), but significant difference in 1996 (94%, 30%).
j. Reviews include some of the field and plot studies shown.
k. When managed year-around; < 15% reduction during growing season.
I. Varies with soil type, rainfall, type of drainage, and management intensity
m. TKN concentration increases slightly. Decreases P concentration for surface drainage systems, but increases P
concentration for subsurface systems.
n. NO3-N + TKN; TP reduced by 35%
Chapter 2. Agriculture
2-131
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
Flashboard riser-type water level control structures installed in tile mains or outlet ditches on
moderately well-drained soils in the Coastal Plain of North Carolina reduced NO3 movement
through the ditches by 80-95 percent (from 25-40 kg/ha to 1-7 kg/ha) because of a reduction in
effluent volume with no indication of increased denitrification in the field (Gilliam et al. 1979).
The authors note that the reduction in transport through ditches does not necessarily prevent
runoff from entering surface waters through other pathways, but ditch transport would increase
the chance of the NO3 being lost through denitrification or being absorbed by plants as the
groundwater moves toward a seep at a lower elevation. In poorly drained soils, a 50 percent
reduction in NO3 movement through the drainage ditches was attributed to increased water
movement into and through deeper soil horizons (below one m) where denitrification occurred.
Factors considered to explain the reduction in flow volume through ditches were leaking or
bypassing of control structures, evapotranspiration, and deep seepage. The authors conclude
that evapotranspiration would likely explain some of the difference during the summer but that
most of the difference in flow volume was due to an increase in lateral flow from the controlled
fields through the sandy layers below the B horizon and above the aquiclude where essentially
all the NO3 would be denitrified. They therefore conclude that the decreased quantities of NO3-N
moving through the ditches in the poorly drained soils under controlled water conditions
represented a real decrease in the amount of N entering surface waters.
Variability in the effectiveness of controlled drainage was reflected in two modeling studies in
the coastal plain of North Carolina. In one study, it was assumed that controlled drainage
reduced N by 40 percent but only if the slope in the channel is less than one percent and where
the water table can be kept within 0.9 m of the soil surface for 50 percent of the field area
(Wossink and Osmond 2001). Long-term modeling of Core Creek using the DRAINMOD-N
model after calibration on a field-by-field basis with monitoring data from 4.5 years indicated that
controlled drainage could reduce NO3 loads by 10-12 percent, and a combination of controlled
drainage and nutrient management could reduce NO3 loads by 25-33 percent (Smeltz et al.
2005). Modeling predicted that controlled drainage would reduce the drainage outflow by
21.3 percent annually versus conventional drainage (accounting for 11.5 percent of the
reduction in NO3-N leaving the watershed), and that there was a potential for 30 percent and
75 percent NO3 reductions for cotton or soybeans, respectively, as compared to corn.
Studies in the Midwest measured similar NO3 load reductions from controlled drainage. A review
of subsurface drainage in the Midwest revealed that drainage water management has achieved
load reductions of up to 47 percent and 83 percent for NO3 and phosphate, respectively (Kalita
et al. 2007). In a replicated field plot experiment to examine the hydrology, water quality, and
crop yield effects of controlled drainage, uncontrolled drainage, and subirrigation drainage on
Hoytville silty clay soil in Ohio, it was found that controlled drainage during the non-growing
season reduced annual flows by 40 percent, yielding a 45 percent reduction in annual NO3
loads from a corn-soybean production system (Fausey 2005).
2-132 Chapter 2. Agriculture
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
In a 3-year study on Nicollet loam and silt-loam soils in Iowa, water-table depths of 0.3, 0.6, and
0.9 m were maintained in field lysimeters at one site, and water-table depths averaging 0.2, 0.3,
0.6, 0.9, and 1.1m were maintained at a second site to determine the effects of controlled
drainage-subirrigation (CDS) on NO3 concentrations in groundwater (Kalita and Kanwar 1993).
The lowest NO3 concentrations in groundwater were observed under the shallow water-table
depths, with NO3 concentrations in groundwater generally decreasing with increased depths, but
average corn yields were 30 percent lower under the shallow water-table depths of 0.2 to 0.3 m
compared to depths of 0.9 to 1.1 m.
A fairly large number of studies were conducted in Ontario, Canada, to determine the water
quality and yield benefits of controlled drainage systems. In a 3-year evaluation of CDS,
conservation tillage, and corn production practices, annual tile drainage volumes were reduced
by 24 percent with CDS compared with traditional drainage (UD) (Drury et al. 1996). Flow-
weighted mean NO3 concentration and average annual NO3 loss in tile drainage water were
reduced by 25 and 43 percent, respectively, when using CDS (7.9 mg/L N, 14.6 kg/ha N)
instead of UD. The combination of conservation tillage and CDS reduced annual NO3 losses by
49 percent (11.6 kg/ha N) when compared with conventional moldboard plow tillage and UD.
Most (88-95 percent) of the NO3 losses from all treatments occurred in the non-cropping period
from November through April. The increase in NO3 loss through surface runoff for CDS
(1.9 kg/ha N) compared to UD (1.4 kg/ha N) was less than 5 percent of the decrease in loss
through tile drainage.
Measurements from a plot study on a sandy loam soil in Southwestern Ontario, Canada,
showed an 8 percent greater cumulative drainage water volume from the CDS treatment versus
the free-tile drainage (UD) treatment but a 41 percent lower flow-weighted mean NO3
concentration (11.3 mg/L N versus 19.2 mg/L N), a 36 percent lower NO3 export coefficient
(36.8 kg/ha N versus 57.9 kg/ha N), and a 64 percent greater average corn yield (11.0 Mg/ha
versus 6.7 Mg/ha) for CDS versus UD (Ng et al. 2001).
A plot study of a wetland-reservoir system for controlled drainage and subirrigation in
southwestern Ontario found that a CDS system reduced drainage volume by 36 percent, flow-
weighted mean NO3 concentration in tile drainage water by 14 percent, total NO3 loss by
27 percent (46.3 kg N/ha versus 63.6 kg N/ha), dissolved organic P by 47 percent, and dissolved
inorganic P by 54 percent compared to a free drainage system (UD) (Tan et al. 2003). Tile
drainage water and surface runoff water from agricultural fields were routed into a wetland
reservoir and then recycled back through the CDS to provide subsurface irrigation during times of
crop water deficit. NO3 uptake by plants and algae in the reservoir and increased corn
(91 percent) and soybean (49 percent) yields contributed to the reductions in NO3 loss for the
CDS system.
Chapter 2. Agriculture 2-133
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
In a comparison of CDS and UD on a 4-ha farm-scale field, CDS did not change total discharge
but reduced flow-weighted mean NO3 concentration in tile drainage water by 38 percent,
reduced total NO3 load by 37 percent, and increased both tomato (11 percent) and corn
(64 percent) yield compared to UD (Tan et al. 2004). During the same period on a 0.4-ha plot-
scale field, CDS reduced total tile drainage volume by 50 percent, reduced flow-weighted mean
NO3 concentration in tile drainage water by 32 percent, reduced total NO3 load by 66 percent,
and increased both soybean (17 percent) and corn (9 percent) yield relative to UD.
A study comparing both CD and CDS versus UD at two fertilization rates (N1: 150 kg N/ha
applied to corn, no N applied to soybean; N2: 200 kg N/ha applied to corn, 50 kg N/ha applied to
soybean) on a clay loam soil in Ontario, Canada, documented that CD and CDS reduced N
loads from tile drainage by 44 and 66 percent, respectively, relative to UD at the N1 rate, and by
31 and 68 percent, respectively, at the N2 rate (Drury et al. 2009). The N concentrations in tile
flow events with the UD treatment exceeded Ontario's provisional long-term aquatic life limit for
freshwater (4.7 mg N L-1) 72 percent and 78 percent of the time at the N1 and N2 rates,
respectively, but only 24 percent and 40 percent, respectively, with CDS. Crop yields from CDS
were increased by an average of 2.8 percent relative to UD at the N2 rate, but were reduced by
an average of 6.5 percent at the N1 rate.
A CDS system managed at a depth of 0.050 m reduced total drain discharge over two growing
seasons by 42 percent versus UD in a field study in eastern Ontario (Mejia and Mandramootoo
1998). Growing-season mean NO3 concentrations in drainage water were reduced by CDS at
both a depth of 0.050 m (61-84 percent) and a depth of 0.075 m (52-75 percent) versus UD.
Because of high rainfall and failure to manage the CDS under the wet conditions, discharge was
over five times greater in 1995 under CDS at each depth, resulting in no significant change in
NO3 load. In 1996, however, growing-season NO3 loads were reduced by 94 percent and
30 percent by the 0.050 m and 0.075 m CDS, respectively.
Monitoring over 2 years of four replicate plots each of surface runoff, CD at 1.1m below the soil
surface, and CDS at 0.8 m in Baton Rouge showed that 67 percent of the annual NO3 loss in tile
drainage for the CD and CDS systems occurred during the 150-day growing season (Grigg et
al. 2003). There were no statistical differences between the surface, subsurface, or total NO3
loads from the CD and CDS systems.
Compilations and reviews of literature on controlled drainage have yielded largely consistent
findings. On the basis of approximately 125 site-years of data collected at 14 locations in
eastern North Carolina (Evans et al. 1996):
• Controlled drainage, when managed all year, reduces total outflow by approximately
30 percent compared to uncontrolled systems, although outflows vary widely depending
on soil type, rainfall, type of drainage system and management intensity. For example,
2-134 Chapter 2. Agriculture
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
control during only the growing season typically reduces outflow by less than 15 percent.
The effect of controlled drainage on peak outflow rates varies seasonally. Drainage control
reduces peak outflow rates during dry periods (summer and fall) but can increase peak
outflow rates during wet periods (winter and spring), depending on the control strategy.
• Drainage control has little net effect on TN and P concentrations in drainage outflow.
Controlled drainage can reduce NO3-N concentrations in drainage outflow by up to
20 percent, but TKN concentrations are somewhat increased. Controlled drainage tends
to decrease P concentrations on predominately surface systems but has the opposite
effect on predominately subsurface systems. Seasonal variations can also occur,
depending on rainfall, soil type, and the relative contribution of surface or subsurface
drainage to total outflow.
• Controlled drainage reduces N and P transport at the field edge, primarily because of the
reduction in outflow volume. In 14 field studies, drainage control reduced the annual
transport of TN (NO3-N and TKN) at the field edge by 10 kg/ha, or 45 percent, and TP
by 0.12 kg/ha, or 35 percent. Again, the reductions at individual sites were influenced by
rainfall, soil type, type of drainage system, and management intensity.
In a broader review of methods to reduce NO3 in drainage water, it was estimated that the
potential for NO3 load reduction with controlled drainage is approximately 50 percent
(Appelboom and Fouss 2006). Skaggs and Youssef (2008) reported a wide range of discharge
reduction (17-85 percent) and NO3 load reduction (18-85 percent) in a summary of studies
conducted in North Carolina, Ohio, Sweden, and Canada. The authors note that controlled
drainage increases evapotranspiration, surface runoff, and deep and lateral seepage, with
evapotranspiration accounting for only 8-15 percent of the reduction in subsurface drainage
compared to conventional drainage and seepage effects dependent on the size and boundary
conditions of the fields under controlled drainage. The effects of size and boundary condition on
discharge were illustrated by the different findings for field and plot studies in Canada (Tan et al.
2004). Reductions in NO3 concentration from controlled drainage were minimal in most studies,
so it is important to know what happens to the NO3 in the seepage water. Evidence indicates
that in poorly or very poorly drained soils, the NO3 is reduced at depths greater than 1 m or so,
providing effective reduction of N losses to the environment.
Ditch management practice effectiveness
In a 2-year study of two experimental farm drainage ditches serving land planted in a summer
row crop/winter fallow sequence in northern Mississippi, monthly baseflow and stormflow
(28 storms) regression results indicated that drainage ditches reduced NO3 and ammonia over
the length of the ditch for both growing and dormant seasons (Kroger et al. 2007). Ditches
reduced the maximum farm effluent dissolved inorganic N load, defined as the highest load
Chapter 2. Agriculture 2-135
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
attained spatially within the drainage ditch as a result of the combination of surface and
subsurface flow processes, by an average of 57 percent.
Sediment from two similar drainage ditches in the Atlantic coastal plain were sampled (0-5 cm)
after one of the ditches had been dredged, removing fine-textured sediments (clay = 41 percent)
with high organic matter content (85 g/kg) and exposing coarse-textured sediments (clay =15
percent) with low organic matter content (2.2 g/kg) (Shigaki et al. 2008). Laboratory testing in a
flume revealed that under conditions of low initial P concentrations, sediment from the dredged
ditch released 13 times less P to the water than did sediment from the ditch that had not been
dredged, but the sediments from the dredged ditch removed 19 percent less P from the flume
water when it was spiked with dissolved P to approximate long-term runoff concentrations.
Irradiation of sediments to destroy microorganisms revealed that biological processes
accounted for up to 30 percent of P uptake in the coarse-textured sediment of the dredged ditch
and 18 percent in the fine-textured sediment of the undredged ditch.
Because vegetation in ditches increases sediment retention, cycles nutrients, and promotes the
development of soil structure, management procedures that encourage ditch vegetation, such
as targeted clean-outs and gradual inundation, can increase the stability and ecosystem
services of ditch soils (Needelman et al. 2006). A study in Florida to evaluate P characteristics
of agricultural ditch soils in the Lake Okeechobee Basin found that in-ditch management
practices, such as using soil amendments or controlled drainage, could be useful to reduce P
loss from ditch soils (Dunne et al. 2006).
Bioreactors effectiveness
Several studies have measured the effectiveness of bioreactors in removing NO3 and other
contaminants from agricultural drainage water (Table 2-29).
A review of bioreactors in the Midwest found that they could reduce NO3 levels by 60-100
percent (Kalita et al. 2007). In addition, the authors identified the following advantages of
bioreactors:
• They use proven technology
• They require no modification of current practices
• No land needs to be taken out of production
• There is no decrease in drainage effectiveness over time
• They require little or no maintenance
• They can last for up to 20 years
2-136 Chapter 2. Agriculture
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
Table 2-29. Measured NO3 removal rates for bioreactors
Location
Iowa
Minnesota
Ontario,
Canada
Ontario,
Canada
Ontario,
Canada
Various
Various
Practice
Wood-chip denitrification walls
Wood chip bioreactor
Denitrification reactor using
wood particles — Upflow Design
In-ditch wood chip bioreactor
Subsurface wood mulch
bioreactor (pilot scale)
200-L fixed-bed bioreactors with
sand, tree bark, wood chips,
leaf compost (pilot scale)
Constructed bioreactors (review
article)b
Constructed bioreactors (review
article)b
Flow-
through
rate
(L/min)
7.8
24
0.6-1.4
0.007-0.042
Removal (%)
N03-N
cone.
65%a
32%
52%
78%
58%
60%-90%
60%-100%
N03-N
load
61%-68%a
99%
Source
Jaynes et al.
2004
Thorstensen
No date
Robertson and
Merkley 2009
Robertson et
al. 2000
Blowes et al.
1994
Appelboom and
Fouss 2006
Kalita et al.
2007
Notes:
a. Reduction compared to uncontrolled drainage.
b. Reviews include some of the other studies shown.
In an Iowa study comparing several tile and cropping modifications for reducing NO3 in tile
drainage versus the NO3 concentration in drainage from a UD treatment (tile at 1.2 m), it was
found that denitrification walls (DW) reduced the NO3 concentration in tile drainage by an
average of 65 percent and the tile drainage N load by 61-68 percent compared to UD (Jaynes
et al. 2004).
Two denitrification reactor designs (a lateral flow design and an upflow design) using fine and
coarse wood particles were tested under baseflow conditions in southern Ontario; the former
over a 26-month period on drainage from a cornfield, and the latter over a 20-month period on
drainage from a golf course (van Driel et al. 2006). Removal by the reactor at the cornfield site
averaged 3.9 mg N/L at an average flow-through rate of 7.7 L/min and an average influent NO3
concentration of 11.8 mg N/L. With an average flow-through of 7.8 L/min and influent NO3
concentration of 3.2 mg N/L, removal by the reactor at the golf course site averaged 1.7 mg N/L.
Mass balance calculations indicate that carbon consumption from denitrification was less than
2 percent per year, showing the potential for the reactors to operate for a number of years
without the need for media replenishment.
Chapter 2. Agriculture
2-137
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
A 40-m3 woodchip bioreactor was trenched into the bottom of an existing agricultural drainage
ditch in Ontario, Canada, with flow induced through the reactor by construction of a gravel riffle
in the streambed (Robertson and Merkley 2009). Over the first year and a half of operation, a
mean influent NO3 concentration of 4.8 mg/L was reduced to 1.04 mg/L at a mean reactor flow
rate of 24 L/min. A series of flow-step tests, facilitated by an adjustable height outlet pipe,
demonstrated that NO3 mass removal generally increased with increasing flow rate. Silt
accumulation reduced reactor flow rates over time, but design modifications were implemented
to address the problem.
In a 1-year pilot-scale study, two 200-L fixed-bed bioreactors containing coarse sand and organic
carbon (tree bark, wood chips, and leaf compost) were used to treat NO3 contamination from
agricultural runoff (Blowes et al. 1994). At inflow rates of 10-60 L/day, NO3-N concentrations of
3-6 mg/L in farm-field drainage tiles were reduced by the reactors to less than 0.02 mg/L.
In Ontario, a pilot-scale assessment of a plywood-framed (1.9 m3) subsurface reactor filled with
coarse wood mulch documented a 58 percent removal of NO3 from farm drainage water influent
at hydraulic loading rates ranging from 800 to 2,000 L/day (Robertson et al. 2000). NO3
consumption rates were temperature dependent, ranging from 5 mg/L N per day at 2-5 °C, to
15-30 mg/L N per day at 10-20 °C but did not deteriorate over the 7-year monitoring period.
Mass-balance calculations of carbon consumption indicated that the reactor could perform well
for at least a decade without carbon replenishment.
In a review of methods to reduce NO3 in drainage water, it was estimated that the potential for
NO3 reduction is 60 to 90 percent for constructed bioreactors (Appelboom and Fouss 2006).
Constructed wetlands effectiveness
In a review of methods to reduce NO3 in drainage water, it was estimated that the potential for
NO3 reduction is 37-65 percent for natural/constructed wetlands, with up to an additional
18 percent if a berm is used in creation of the wetland (Appelboom and Fouss 2006). A
combination of controlled-drainage, constructed wetland, and in-stream denitrification could result
in more than 75 percent NO3 removal before release to larger streams or other surface waters.
Measurement over 3 years of N removal rates in three large (0.3 to 0.8 ha, 1,200 to 5,400 m3 in
volume) constructed wetlands treating tile drainage from corn and soybean fields in southern
Illinois indicated TN removal of 37 percent in the wetlands (Kovacic et al. 2000). The wetlands
also decreased NO3-N concentrations of inlet water by 28 percent, and coupling the wetlands
with a 15.3-m buffer strip between the wetlands and the river removed an additional 9 percent
of the tile NO3-N, increasing the N removal efficiency to 46 percent. TP removal was only
2 percent during the 3-year period, with highly variable results in each wetland and year.
2-138 Chapter 2. Agriculture
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
Two agricultural runoff wetlands, W1 (area 0.16 ha, volume 660 m3) and W2 (area 0.4 ha,
volume 1,780 m3), intercepting surface and tile drainage in the Lake Bloomington, Illinois,
watershed, achieved a mass NO3-N retention of 36 percent (Kovacic et al. 2005). Wetlands W1
and W2 reduced overall volume-weighted NO3 concentrations by 42 percent and 31 percent,
respectively. Combined P mass retention was 53 percent, and combined TOC mass retention
was nine percent.
Practice Costs
Dual-purpose drainage/subirrigation systems provide drainage, controlled drainage, and
subirrigation (Evans and Skaggs 1996). Systems designed primarily for drainage might need to
be redesigned or managed more intensively to serve as dual-purpose systems. The three major
expenses of installing and operating a drainage and subirrigation system are the cost of a water
supply, underground tubing installation, and land grading (Evans etal. 1996). If subirrigation is
not part of the system, a water supply is not needed, but increased yields realized with
subirrigation can contribute to NO3 reductions because of increased crop uptake. On the basis
of estimates for 1996, water supply ponds sufficient to irrigate approximately 40 ha would cost
about $68,735-$82,381 in 2010 dollars, but other water supplies (e.g., stream) could be much
cheaper. Underground tubing installation costs are generally the largest single expense, varying
with the total footage, tubing diameter, installation method, and whether filter material is used.
The amount of tubing needed depends on the hydraulic conductivity of the soil, with spacing
ranging from 40 to 100 feet in North Carolina. The cost of 10-cm tubing ranges from about
76 cents to just over $1 per m (2010 dollars), with filter material adding another 32 to 54 cents
per m. The cost to install underground tubing depends on the specific job, but can range from
about $1.36/m to $2.27/m for 10-cm tubing. The total cost to install tubing at 10-m spacing is
about $2,688/ha (2010 dollars), whereas the cost for 30-m spacing is about $890/ha. Land
grading could add $170 to $860/ha to the cost, and the cost of control structures ranges from
about $400 to more than $4,000. Finally, installation generally requires field borders to stabilize
open ditches at a cost of about $100 per production hectare.
A cost analysis for controlled drainage in the lower coastal plain of North Carolina assumed the
need for a surface drainage system of 0.9- to 1.5-m-deep open ditches, a flashboard riser
installed in the collector canal, a corrugated metal pipe culvert for an outlet, and concrete to
stabilize the riser (Wossink and Osmond 2001). It was assumed that there would be no
installation and maintenance costs for ditches because they were part of the preexisting
condition. On the basis of a land slope of 0.1 to 0.4 m/km, it was assumed that there would be
one structure per mile in the canal on a 0.6- to 0.75-m contour interval, meaning that one control
structure in the main canal would serve 130 hectares. It was also assumed that under controlled
drainage soybeans and cotton yields would increase by 2 percent or more, corn yields would
increase by 5 percent or more, and wheat and tobacco yields would not increase. Installation
costs for controlled drainage were estimated to be $57.80/ha (2008 dollars), while annual
Chapter 2. Agriculture 2-139
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
maintenance was estimated at $3.80/ha, and benefits from yield increases were estimated at
$6.10/ha to $33.50/ha. Assuming cost-share availability of about $45/ha, the authors concluded
that cost-shared controlled drainage was financially practical for the lower coastal plain of NC.
In a demonstration plot in Minnesota, the costs associated with controlled drainage included
drainage control structures, design, installation, extra pipe and installation, totaling about $35/ha
for a 65-ha field (Binstock 2009). Tile spacing was set at 22.8 m, using 10-cm diameter laterals
on a slope of just under 1 percent. It has been estimated that drainage management systems
cost about $50 to $500/ha more than conventional drainage systems (Newby 2009).
Water control structures for drainage water management cost from about $535 to $2,120 (2010
dollars) depending on height, size of tile, structure design, manufacturer, and whether it is
automated (Frankenberger et al. 2006). Installation costs for structures are about $215 for basic
structures, increasing with size and complexity. Assuming flat terrain, a single structure could
serve eight hectares at a cost of $70 to $270 per ha. Water control structures cost $2,560 each
in Virginia (USDA-NRCS 2010).
Both a lateral flow design and an upflow design bioreactor tested in Ontario were successful in
achieving maintenance-free operation during all seasonal conditions, including unassisted
startup after drought and freeze periods (van Driel et al. 2006). Construction cost per unit N
removal for bioreactors designed to manage baseflow conditions are expected to be similar to
the cost for constructed wetlands, but less land is required for the bioreactors.
A woodchip bioreactor (38 m long by 1.8 m deep by 0.6-0.9 m wide) in Minnesota cost
approximately $3,200 to construct (Minnesota Department of Agriculture No date). Control
structures cost $1,500, trenching cost $1,100, and $600 was spent on woodchips. Serving
approximately 3.2 ha, the bioreactor cost is about $990/ha and is expected to work for about
20 years. The cost of a 60-m bioreactor ranges from about $2,900 to $4,300 (2010 dollars)
depending on materials and design (Morrison 2008).
4.5 Animal Agriculture
AFOs congregate animals and typically maintain feed, wastes, and production operations on a
small land area when under pasture or grazing. Animal production can cause water pollution by
leaching and runoff of organic matter, N, P, pathogens, and heavy metals from animal
congregation areas or other parts of the facility during regular operation of a facility if not properly
managed (for further information regarding storage of manure and wastewater, see Section 2).
Key strategies for edge of field trapping and treatment of runoff include VFS and other techniques
to capture runoff from feedlots, barnyards, pasture and grazing lands, and other facility areas and
remove sediment, nutrients, and other pollutants before delivery to surface waters.
2-140 Chapter 2. Agriculture
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
AFOs using grazing and pasture land include nutrients and pathogens in runoff from areas of
waste deposition and soil loss from areas of degraded vegetation cover. While livestock
exclusion (see Section 2) and pasture management (see Section 3.4) are often the main
approaches to managing water quality effects from grazing livestock, non-grazed, vegetated
buffer strips or other edge-of-field practices are often recommended to protect waterbodies from
sediments and nutrients in runoff from grazed pastures.
Implementation Measure A-20:
Manage runoff from livestock production areas under grazing and pasture to
minimize off-farm transport of nutrients and sediment.
Practice Effectiveness
Production area effectiveness
Koelsch et al. (2006) presented the following conclusions about the application of vegetative
treatment systems (VTS) to manage runoff from open lot livestock production areas:
• The pollutant reduction resulting from a VTS is based on two primary mechanisms:
(1) sedimentation, typically occurring within the first few meters of a VTS, and
(2) infiltration of runoff into the soil profile. System design based on sedimentation and
infiltration is necessary to achieve a required performance level for concentrated AFO
(CAFO) application.
• Critical design factors specific to attaining high levels of pollutant reduction within a VTS
include pretreatment, sheet flow, discharge control, siting, and sizing. Critical
management factors include maintaining a dense vegetation stand and sheet flow of
runoff across VTA as well as minimizing nutrient accumulation.
The authors report numerous pollutant removal rates for a variety of VTS under a broad range
of circumstances. While the study focused on VTA specifically related to providing an alternative
method of manure and wastewater storage for CAFOs, the practice can be applied more
broadly in animal agriculture. In general, the literature reports 70-90 percent TS removal,
80 percent N removal, 70 percent P removal, and 77 percent fecal coliform removal from CAFO
runoff treated by VTS.
In Nebraska, Woodbury et al. (2000, 2002) tested a flat-bottom terrace to collect runoff from a
beef feedlot to provide temporary liquid storage and accumulate settable solids, while
distributing the liquid fraction uniformly across a VFS. No runoff left the VFS, indicating that the
basin discharge was used for grass production. In a follow-up study, Woodbury et al. (2003)
Chapter 2. Agriculture 2-141
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
reported that the system reduced the cumulative mass of TSS (80 percent), VSS (67 percent),
and COD (59 percent).
Kim et al. (2003) studied flow and P transport through a VFS receiving milkhouse wastewater
and barnyard runoff from two New York dairy farms. Although 33 m-40 m VFS eventually
reduced soluble P to less than 0.2 mg/L, P was less effectively removed where soil saturation
occurred. Wastewater entering a VFS should be distributed uniformly to avoid soil saturation.
In Montana, Fajardo et al. (2001) reported on the effectiveness of VFS using tall fescue in
treating runoff from livestock manure stockpiles. Runoff NO3-N concentrations were reduced by
97-99 percent by a VFS. Coliform bacteria counts were reduced by 64-87 percent, although
bacteria counts in runoff leaving the VFS remained elevated, even for treatments not receiving
manure.
VFS were effective in removing a broad range of constituents from a Kansas beef feedlot runoff
pretreated by a settling basin (Mankin and Okoren 2003). The first 30 m provided most or all the
reductions found within the 150-m VFS studied: reductions averaged 85 percent of inflow water,
85 percent of sediment, 77 percent of N, and 84 percent of P. Fecal bacteria removal by the
VFS was on the order of 1-log: reductions at 30 m ranged from 84 percent for FC and FS to
91 percent for E. coli.
In Illinois, Trask et al. (2004) reported that a VFS can be a BMP for controlling the pathogen
Cryptosporidium in runoff from animal production facilities. The vegetative surface was very
effective in reducing C. parvum in surface runoff; for all slopes and rainfall intensities, recovery
of C. parvum oocysts was considerably less from a vegetated surface than from the bare-
ground conditions. For a 25.4 mm/h rainfall event, recovery of oocysts in overland flow from the
VFS varied from 0.6 to 1.7 percent, while those from the bare ground condition varied from
4.4 to 14.5 percent. For the 63.5 mm/h rainfall, the recovery percentages of oocysts varied from
0.8 to 27.2 percent from the VFS, and 5.3 to 59 percent from bare-ground conditions.
Hubbard et al. (2007) tested the performance of grass-forest vegetated buffers in assimilating N
from overland flow application of swine lagoon effluent in Georgia. The buffers approximated
60 m in length by 90 m in width. The upper 10 m of each buffer was in grass, while the
downslope area was in mature or newly planted pines. Shallow groundwater under the buffers
showed NO3-N concentrations 20-30 m downslope to be less than 10 mg/L. On those buffers,
NO3-N concentrations in shallow groundwater were near background levels 5 years after
wastewater application commenced. This study demonstrated that the ratio of buffer area width
to wastewater application area width on the landscape should be at least 1:1.
2-142 Chapter 2. Agriculture
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
In Kansas, Mankin et al. (2006) quantified beef cattle feedlot runoff quality, particularly during
unstocked conditions, and evaluated reductions of fecal bacteria and nutrients in VFS treating
feedlot runoff. Events when few or no cattle were present averaged 17 percent of TN (20 mg/L),
14 percent of TP (6 mg/L), and 2 percent of the fecal conforms (2.1 x 104 colony forming
units/100 ml_) of events with cattle present. Measured concentration reductions from all events
and VFS averaged 77 percent (fecal coliforms), 83 percent (E. coli), 83 percent (fecal
streptococci), 66 percent (TN), and 66 percent (TP). VFS allowed no discharges for greater than
90 percent of feedlot runoff events at the sites with the ratio of VFS: drainage area greater
than 0.5.
Gilley et al. (2008) compared nutrient transport in runoff from beef feedlots in Nebraska with
loose manure surfaces versus compacted surfaces. No significant differences in feedlot soil
characteristics or nutrient transport in runoff were found between loose and compacted
surfaces. However, concentrations of E. coli were significantly greater in runoff from the loose
surface feedlots.
In Finland, Narvanen et al. (2008) tested a ferric sulfate dosing system to treat runoff from horse
paddocks; runoff was then discharged into a sedimentation pond and sand filter. Dissolved P
was reduced by 95 percent, TP by 81 percent.
Robertson and Merkley (2009) demonstrated an in-stream bioreactor using woodchips to
promote denitrification of agricultural drainage in Ontario, Canada. Over the first 1.5 years of
operation, mean influent NO3-N of 4.8 mg/L was attenuated to 1.04 mg/L (a 78 percent
reduction) at a mean reactor flow rate of 24 L/min. When removal rates were not NO3-limited,
areal mass removal ranged from 11 mg N/m2/h at 3 °C to 220 mg N/m2hr at 14°C, exceeding
rates reported for some surface-flow constructed wetlands by a factor of about 40.
Table 2-30. Summary of reported practice effects resulting from VFS treatment of AFO runoff
Location
Various
Nebraska
New York
Study
type
Review
BMP
BMP
Practice
Vegetated
treatment
systems
Settling
basin/VFS
VFS
Practice effects
Literature reports removals of about 70%-90% TS,
about 80% N, about 70% P, and about 77% fecal
coliform from CAFO runoff treated by diverse
vegetated treatment systems.
No runoff left the VFS treating beef feedlot runoff;
the system reduced the cumulative mass of TSS
(80%), VSS (67%), and COD (59%)
Although 33-40 m VFS treating milkhouse waste
and barnyard runoff reduced soluble P to
< 0.2mg/L in most cases; P was less effectively
removed in the areas where soil saturation
occurred.
Source
Koelsch et al.
2006
Woodbury et
al. 2000 2002,
2003
Kim et al.
2003
Chapter 2. Agriculture
2-143
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
Table 2-30. Summary of reported practice effects resulting from VFS treatment of AFO runoff
(continued)
Location
Montana
Kansas
Illinois
Georgia
Kansas
Nebraska
Finland
Ontario,
Canada
Study
type
BMP
BMP
BMP
BMP
BMP
BMP
BMP
BMP
Practice
VFS
Settling
basin, VFS
VFS vs. bare
soil
Grass-forest
bufferb
VFS, feedlot
stocking rate
Feedlot
surface
Ferric
sulfate, sand
filter
Woodchip
bioreactor
Practice effects
VFS treating runoff from manure stockpiles
reduced NO3-N concentrations by 97%-99% and
coliform bacteria counts by 64%-87%a
Reductions averaged 85% of inflow water, 85% of
sediment, 77% of N, and 84% of P. Bacteria
reductions at 30 m ranged from 84% for FC and
FS to 91% for E. coli. The first 30 m provided most
or all of the reductions.
Fewer Cryptosporidium oocysts were passed in
overland flow from a vegetated surface than from
the bare-ground conditions. Fora 25.4 mm/h
rainfall event, oocyst recovery from the VFS were
0.6-1.7%, vs. 4. 4 to 14. 5% from bare ground. For
the 63.5 mm/h rainfall, the recovery percentages of
oocysts varied from 0.8%-27.2% from the VFS,
and 5.3%-59% from bare ground.
Shallow groundwater under the buffers showed
NO3-N concentrations 20-30 m downslope to be
<10 mg/L. On these buffers, NO3-N concentrations
in shallow groundwater were near background
levels 5 years after wastewater application began.
Runoff when few or no cattle were present
averaged 17% of the TN, 14% of the TP, and 2%
of the fecal conforms vs. events with cattle present.
Concentration reductions averaged 77% (fecal
conforms), 83% (£. coli), 83% (fecal streptococci),
66% (TN), and 66% (TP).
No significant differences in nutrient transport in
runoff were found between loose and compacted
feedlot surfaces. E. coli counts were significantly
greater in runoff from the loose surface feedlots.
Dissolved P was reduced by 95%, TP by 81%
using a ferric sulfate dosing system and sand filter
to treat runoff from horse paddocks
Treating AFO drainage, NO3-N was attenuated to
1.04 mg/L (78% reduction); areal mass removal
ranged from 1 1 mg N/m2/h at 3 °C to 220 mg
N/m2hr at 14 °C, exceeding rates reported for
some surface-flow constructed wetlands by a
factor of about 40.
Source
Fajardo et al.
2001
Mankin and
Okoren 2003
Trask et al.
2004
Hubbard et al.
2007
Mankin et al.
2006
Gilley et al.
2008
Narvanen et
al. 2008
Robertson
and Merkley
2009
Notes:
a. Bacteria counts in runoff leaving the VFS remained elevated, even for treatments not receiving manure
b. Upper 10 m in grass, 20-30 m downslope in trees
2-144
Chapter 2. Agriculture
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
Buffer/filter strips treating pasture runoff
Sotomayor-Ramirez et al. (2008) tested 10- and 20-m grassed filter strips treating runoff from
grazed pasture amended with dairy manure sludge in Puerto Rico. Filter strips reduced TP and
dissolved P concentrations by 29 percent and 32 percent at 10 m, and by 57 percent and
49 percent at 20 m, respectively. A 27 percent decrease in TKN concentration was observed in
one field as a result of the 20-m filter strip.
Tate et al. (2000) evaluated the potential water quality improvements from 10-m buffer strips on
irrigated land in California. The 10-m buffer did not significantly reduce concentrations and load
of NO3-N in runoff from sprinkler and flood irrigated pastures. The buffer also failed to reduce TP
concentration under either irrigation system, or TP and TSS load under sprinkler irrigation.
The presence of a vegetated buffer of any size (from 1 to 25 m), generally reduced median fecal
coliform bacteria concentrations and loads in runoff from Oregon pasture land by more than
99 percent (Sullivan et al. 2007).
Other practices treating pasture runoff
Tanner et al. (2005) reported on the performance of a surface-flow constructed wetland
(occupying about 1 percent of the watershed area) treating subsurface drainage from rain-fed,
dairy cattle grazed pasture in New Zealand. TN mass removal efficiency was 79 percent
(841 g/m2 per year) the first year but declined to 21 percent (40 g/m2 per year) in the second
year, associated with changes in the magnitude, speciation and seasonal pattern of N export
from the watershed. TP export rose by 101 percent (5.0 g/m per year) after passage through the
wetland in the first year but decreased by 12 percent (0.2 g/m2 per year) in the second year. The
results show that constructed wetlands composing similar to 1 percent of watershed area can
markedly reduce N export via pastoral drainage but could be net sources of NH4-N, DRP and
TP during establishment.
Knox et al. (2008) examined benefits to water quality provided by a natural, flow-through
wetland receiving runoff from irrigated pasture in California. The wetland reduced loads of TSS
(77 percent), NO3 (60 percent), and E. coli (68 percent). Retention of TN, TP, and SRP was
between 35 and 42 percent of loads entering the wetland.
Chapter 2. Agriculture 2-145
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
Table 2-31. Summary of reported practice effects resulting from buffer/wetland treatment of
pasture runoff
Location
Puerto
Rico
California
Oregon
New
Zealand
California
Study
type
BMP
BMP
BMP
plots
BMP
BMP
Practice
Grassed
filter strips
Buffer
Vegetated
buffer
Constructed
wetland
Natural
wetland
Practice effects
Filter strips treating runoff from grazed pasture
reduced TP and dissolved P concentrations by 29%
and 32% at 10 m, and by 57% and 49% at 20 m,
respectively. A 27% decrease in TKN concentration
was observed in one field as a result of the 20-m filter
strip
10-m buffer did not significantly reduce
concentrations and load of NO3-N in runoff from
sprinkler and flood irrigated pastures. The buffer also
failed to reduce TP concentration under either
irrigation schemes, orTP and TSS load under
sprinkler irrigation
The presence of a vegetated buffer of any size (from
1 to 25 m) reduced median fecal coliform bacteria
concentrations and loads in runoff by more than 99%.
Surface-flow constructed wetland (occupying about
1% of watershed area) treating subsurface drainage
dairy cattle grazed pasture: TN mass removal
efficiency was 79% (841 g/m2 per year) the first year
but declined to 21% (40 g/m2 per year) in the second
year. TP export rose by 1 01 % (5.0 g/m per year) after
passage through the wetland in the first year but
decreased by 12% (0.2 g/m2 per year) in the second
year.
Wetland receiving runoff from irrigated pasture
reduced loads of TSS (77%), NO3 (60%), and E. coli
(68%). 35% to 42% of TN, TP, and SRP loads
entering the wetland were retained.
Source
Sotomayor-
Ramirez et
al 2008
Tate et al.
2000
Sullivan et
al. 2007
Tanner et al.
2005
Knox et al.
2008
2-146
Chapter 2. Agriculture
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
5 References
Aarnink, A.J.A., and M.W.A. Verstegen. 2007. Nutrition, key factor to reduce environmental load
from pig production. Livestock Science 109:194-203.
Adler, P.R., and P.L. Sibrell. 2003. Sequestration of phosphorus by acid mine drainage floe.
Journal of Environmental Quality 32:1122-1129.
Adrizal, A., P.M. Patterson, R.M. Hulet, R.M. Bates, C.A.B. Myers, G. Martin, R.L. Shockey,
M. Van der Grinten, D.A. Anderson, and J.R. Thompson. 2008. Vegetative buffers for fan
emissions from poultry farms: 2. ammonia, dust and foliar nitrogen. Journal of
Environmental Science and Health Part B-Pesticides Food Contaminants and Agricultural
Wastes 43(1 ):96-103.
Agouridis, C.T., D.R. Edwards, S.R. Workman, J.R. Bicudo, B.K. Koostra, E.S. Vanzant, and
J.L. Taraba. 2005. Streambank erosion associated with grazing practices in the humid
region. Transactions off/7eX\SX\£48(1):181-190.
Agyin-Birikorang, S., G.A. O'Connor, LW. Jacobs, K.C. Makris, and S.R. Brinton. 2007. Long-
term phosphorus immobilization by a drinking water treatment residual. Journal of
Environmental Quality 36:316-323.
AN, I., S. Barrington, R. Bonnell, J. Whalen, and J. Martinez. 2007. Surface irrigation of dairy
farm effluent, Part II: System design and operation. Biosystems Engineering 96:65-77.
Allen, B.L., and A.R. Mallarino. 2008. Effect of liquid swine manure rate, incorporation, and
timing of rainfall on phosphorus loss with surface runoff. Journal of Environmental Quality
37:125-137.
Andraski, T.W., L.G. Bundy, and K.C. Kilian. 2003. Manure history and long-term tillage effects
on soil properties and phosphorus losses in runoff. Journal of Environmental Quality
32:1782-1789.
Appelboom, T.W., and J.L. Fouss. 2006. Methods for Removing Nitrate Nitrogen from
Agricultural Drainage Waters: A Review and Assessment. ASAE Meeting Paper No.
062328, St. Joseph, Ml 2006 ASAE Annual International Meeting.
Arkansas Cooperative Extension Service. 2006. Improving Poultry Litter Management and
Carcass Disposal. University of Arkansas, Little Rock.
. Accessed April
12,2010.
Chapter 2. Agriculture 2-147
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
Arriaga, H., M. Pinto, S. Calsamiglia, and P. Merino. 2009. Nutritional and management
strategies on nitrogen and phosphorus use efficiency of lactating dairy cattle on
commercial farms: An environmental perspective. Journal of Dairy Science 92:204-215.
Avalos, J.M.M., P.S. Fouz, E.V. Vaquez, A.P. Gonzalez, and I. Bertol. 2007. Crop Residue
Effects on Organic Carbon, Nitrogen, and Phosphorus Concentrations and Loads in
Runoff Water. In Proceedings of the 10th International Symposium on Soil and Plant
Analysis, Budapest, Hungary, Taylor & Francis, Inc.
Bakhsh, A., R.S. Kanwar, J.L. Baker, J. Sawyer, and A. Malarino. 2009. Annual swine manure
applications to soybean under corn-soybean rotation. Transactions of the ASABE
52:751-757.
Bambo, S.K., J. Nowak, A.R. Blount, A.J. Long, and A. Osiecka. 2009. Soil nitrate leaching in
silvopastures compared with open pasture and pine plantation. Journal of Environmental
Quality 38(5): 1870-1877.
Barbarika, A. Jr. 1987. Costs of soil conservation practices. In Optimum Erosion Control at
Least Cost: Proceedings of the National Symposium on Conservation Systems. American
Society of Agricultural Engineers St. Joseph, Ml, pp. 187-195.
Bechmann, M.E., P.J.A. Kleinman, A.N. Sharpley, and L.S. Saporito. 2005. Freeze-thaw effects
on phosphorus loss in runoff from manured and catch-cropped soils. Journal of
Environmental Quality 34:2301-2309.
Beck, M.A., L.W. Zelazny, W.L Daniels, and G.L. Mullins. 2004. Using the Mehlich 1 Extract to
Estimate Soil Phosphorus Saturation for Environmental Risk Assessment. So/7 Science
Society of America Journal 68:1762-1771.
Bedard-Haughn, A., K.W. Tate, and C. van Kessel. 2005. Quantifying the impact of regular
cutting on vegetative buffer efficacy for nitrogen-15 sequestration. Journal of
Environmental Quality 34(5): 1651-1664.
Beegle, D. 2000. Integrating phosphorus and nitrogen management at the farm level,
Agriculture and Phosphorus Management. In Agriculture and Phosphorus Management:
The Chesapeake Bay, A.N. Sharpley, ed., CRC Press, pp. 159-168.
Bekele, A., A.M.S. McFarland, and A.J. Whisenant. 2006. Impacts of a manure composting
program on stream water quality. Transactions of the ASABE 49(2):389-400.
Bergstrom, L.F. and W.E. Jokela. 2001. Ryegrass cover crop effects on nitrate leaching in
spring barley fertilized with 15NH415NO3. Journal of Environmental Quality 30:1659-1667.
2-148 Chapter 2. Agriculture
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
Bernard, J.C. and J.D. Pesek. 2007. Potential Adoption and Marketing of High Available
Phosphorus (HAP) Corn. Final Report. Food and Resource Economics, University of
Delaware, Newark, DE.
. Accessed April 12,
2010.
Bicudo, J.R. and S.M. Goyal. 2003. Pathogens and manure management systems: A review.
Environmental Technology 24( 1): 115-130.
Binstock, L. 2009. Agricultural drainage water management steps into the future. Land and
Water March/April 2009:52-55 .
Accessed February 21, 2010.
Blackmer, A.M., and A.P. Mallarino. 1996. Cornstalk Testing to Evaluate Nitrogen Management
(PM-1584). Iowa State University Extension.
. Accessed February 9, 2010.
Blazier, M.A., L.A. Gaston, T.R. Clason, K.W. Farrish, B.P. Oswald, and H.A. Evans. 2008.
Nutrient dynamics and tree growth of silvopastoral systems: Impact of poultry litter.
Journal of Environmental Quality 37(4): 1546-1558.
Blowes, D.W. D. Robertson, C.J. Ptacek, and C. Merkley. 1994. Removal of agricultural nitrate
from tile-drainage effluent water using in-line bioreactors. Journal of Contaminant
Hydrology 15(3): 15.
Bolan, N.S., S. Laurenson, J. Luo, and J. Sukias. 2009. Integrated treatment of farm effluents in
New Zealand's dairy operations. Bioresource Technology 100(22):5490-5497.
Borin, M., and E. Bigon. 2002. Abatement of NO3-N concentration in agricultural waters by
narrow buffer strips. Environmental Pollution 117(1):165-168.
Borin, M., M. Vianello, F. Morari, and G. Zanin. 2005. Effectiveness of buffer strips in removing
pollutants in runoff from a cultivated field in North-East Italy. Agriculture Ecosystems &
Environment 105(1-2):101-114.
Bosworth, S. 2006. Using cover crops in corn silage systems. University of Vermont Extension.
. Accessed
April 20, 2010.
Brandi-Dohrn, F.M., M. Hess, J.S. Selker, R.P. Dick, S.M. Kauffman, and D.D. Hemphill 1997.
Nitrate leaching under a cereal rye cover crop. Journal of Environmental Quality
26(1): 181-188.
Chapter 2. Agriculture 2-149
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
Brauer, D., G.E. Aiken, D.H. Pote, S.J. Livingston, L.D. Norton, T.R. Way, and J.H. Edwards.
2005. Amendment effects on soil test phosphorus. Journal of Environmental Quality
34(5): 1682-1686.
Brodie, H.L., L.E. Carr, and P. Condon. 2000. A comparison of static pile and turned windrow
methods for poultry litter compost production. Compost Science & Utilization 8(3): 178-189.
Brown, L.C., A. Ward, and N.R. Fausey. 1997. Agricultural Water Table Management Systems.
Ohio State University Fact Sheet AEX 321-97:8.
Bruulsema, T.W., and Q. Ketterings. 2008. Best Management for Fertilizers on Northeastern
Dairy Farms. Fertilizer Best Management Practices series funded by USDA NRCS
Conservation Innovation Grant. International Plant Nutrition Institute. July 2008 Reference
# 08052 Item # 30-3220.
Bundick, H., T. Bruulsema, M. Hunter, J. Lawrence, K. Czymmek, and Q. Ketterings. 2009.
Enhanced-Efficiency Nitrogen Sources. Cornell University Cooperative Extension
Agronomy Fact Sheet Series. Fact Sheet 45.
Burchell, M.R., R.W. Skaggs, G.M. Chescheir, J.W. Gilliam, and LA. Arnold. 2005. Shallow
subsurface drains to reduce nitrate losses from drained agricultural lands. Transactions of
theASAE. 48(3): 1079-1089.
Burchell, M.R., R.W. Skaggs, C.R. Lee, S. Broome, G.M. Chescheir, and J. Osborne. 2007.
Substrate organic matter to improve nitrate removal in surface-flow constructed wetlands.
Journal of Environmental Quality 36(1): 194-207.
Butler, D.M., N.N. Ranells, D.H. Franklin, M.H. Poore, and J.T. Green. 2007. Ground cover
impacts on nitrogen export from manured riparian pasture. Journal of Environmental
Qtya/rty36(1):155-162.
Butler, D.M., N.N. Ranells, D.H. Franklin, M.H. Poore, and J.T. Green. 2008b. Runoff water
quality from manured riparian grasslands with contrasting drainage and simulated grazing
pressure. Agriculture Ecosystems & Environment 126(3-4):250-260.
Butler, D.M., D.H. Franklin, M.L Cabrera, A.S. Tasistro, K. Xia, and L.T. West. 2008a.
Evaluating aeration techniques for decreasing phosphorus export from grasslands
receiving manure. Journal of Environmental Quality 37:1279-1287.
Butler, J.S., and F.J. Coale. 2005. Phosphorus leaching in manure-amended Atlantic Coastal
Plain soils. Journal of Environmental Quality 34:370-381.
Butt, A.J., and B.L. Brown. 2000. The cost of nutrient reduction: A case study of Chesapeake
Bay. Coastal Management 28:175-185.
2-150 Chapter 2. Agriculture
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
Cahill, S., D. Osmond, C. Crozier, D. Isreal, and R. Weisz. 2007. Winter Wheat and Maize
Response to Urea Ammonium Nitrate and a New Urea Formaldehyde Polymer Fertilizer.
Agron Journal 99:1645-1653.
Camacho, R. 1991. Financial Cost Effectiveness of Point and Nonpoint Source Nutrient
Reduction Technologies in the Chesapeake Bay Basin. Interstate Commission on the
Potomac River Basin, Rockville, MD. Unpublished draft.
Cantarella, H., J. A. Quaggio, P. B. Gallo, D. Bolonhezi, R. Rossetto, J. L M. Martins, V. J.
Paulino, and P. B. Alcantara. 2005. Ammonia losses of NBPT-treated urea under Brazilian
soil conditions. Paper presented at IFA International Workshop on Enhanced-Efficiency
Fertilizers, June 28-30, 2005, Frankfurt, Germany.
Cantrell, K.B., J.P. Chastain, and K.P. Moore. 2008. Geotextile filtration performance for lagoon
sludges and liquid animal manures dewatering. Transactions oftheASABE
51 (3): 1067-1076.
Carline, R.F., and M.C. Walsh. 2007. Responses to riparian restoration in the Spring Creek
watershed, central Pennsylvania. Restoration Ecology 15(4):731-742.
Carter, T.A., and M.H. Poore. 1998. Stockpiling Poultry Litter as Part of a Nutrient Plan. PS&T
Guide No. 48. North Carolina Cooperative Extension, NCSU, Raleigh.
. Accessed
April 12, 2010.
Cerosaletti, P.E., D.G. Fox, and L.E. Chase. 2004. Phosphorus reduction through precision
feeding of dairy cattle. Journal of Dairy Science 87:2314-2323.
Chastain, J.P., M.B. Vanotti, and M.M. Wngfield. 2001. Effectiveness of liquid-solid separation
for treatment of flushed dairy manure: a case study. Applied Engineering in Agriculture
17(3): 343-354
Chavan, P.V., K.E. Dennett, E.A. Marchand, and M.S. Gustin. 2007. Evaluation of small-scale
constructed wetland for water quality and Hg transformation. Journal of Hazardous
Materials 149(3): 543-547.
Chavan, P.V., K.E. Dennett, and E.A. Marchand. 2008. Behavior of pilot-scale constructed
wetlands in removing nutrients and sediments under varying environmental conditions.
Water Air and Soil Pollution 192(1-4):239-250.
Chen, D.W. 2001. Environmental challenges of animal agriculture and the role and task of
animal nutrition in environmental protection—Review. Asian-Australasian Journal of
Animal Sciences 14:423-431.
Chapter 2. Agriculture 2-151
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
Chen, Y., and R. Samson. 2002. Integration of liquid manure into conservation tillage corn
systems. Transactions of the ASAE 45:629-638.
Cheng, M. 2001. Removal of chemical oxygen demand and phosphorus from livestock
wastewater by chemical treatment. Taiwanese Journal of Agricultural Chemistry and Food
Science 39(2): 129-134.
Chesapeake Bay Commission. 2004. Cost-Effective Strategies for the Bay.
. Accessed
December 1, 2009.
Chesapeake Bay Program Office. 2010. About the Executive Order.
.
Accessed February 21, 2010.
Chien, S.H., L.I. Prochnow, and H. Cantarella. 2009. Recent developments of fertilizer
production and use to improve nutrient efficiency and minimize environmental impacts.
/Advances in Agronomy 102:267-322. (Elsevier Academic Press, Inc., San Diego).
Choi, E., Y. Yu, M. Cui, Z. Yun, and K. Min. 2008. Effect of biologically mediated pH change on
phosphorus removal in BNR system for piggery waste treatment. Journal of Environmental
Science and Health Part a-Toxic/Hazardous Substances & Environmental Engineering
43(2):154-160.
Choi, I., C.L Munster, D.M. Vietor, R.H. White, C.E. Richards, G.A. Stewart, and B. McDonald.
2003. Use of turfgrass sod to transport manure phosphorus out of impaired watersheds.
Total Maximum Daily Load (TMDL): Environmental Regulations li, Proceedings of the 8-
12 November 2003 Conference, Albuquerque, New Mexico, 518-526.
Clausen, J.C., K. Guillard, C.M. Sigmund, and K.M. Dors. 2000. Ecosystem restoration—Water
quality changes from riparian buffer restoration in Connecticut. Journal of Environmental
Quality 29(6): 1751-1761.
Codling, E.E., R.L. Chaney, and C.L. Mulchi. 2000. Use of aluminum- and iron-rich residues to
immobilize phosphorus in poultry litter and litter-amended soils. Journal of Environmental
Quality 29(6): 1924-1931.
Cornwell, D.A., R.N. Mutter, and C. Vandermeyden. 2000. Commercial Application and
Marketing of Water Plant Residuals. Am. Water Works Assoc. Research Foundation,
Denver, CO.
Coelho, B.R.B., R.C. Roy, and A.J. Bruin. 2006. Nitrogen recovery and partitioning with different
rates and methods of sidedressed manure. So/7 Science Society of America Journal
70:464-473.
2-152 Chapter 2. Agriculture
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
Converse, J.C. and K.G. Karthikeyan 2004. Nutrient and solids separation of flushed dairy
manure by gravity settling. Applied Engineering in Agriculture 20(4):503-507.
Cooke, R., J. Nehmelman, and P. Kalita. 2002. Effect of Tile Depth on Nitrate Transport from
Tile Drainage Systems. ASAE Meeting Paper No. 022017, St. Joseph, Ml 2002 ASAE
Annual International Meeting/CIGR XVth World Congress, Chicago: 16.
Cornell Cooperative Extension. 1997. 1997 Cornell Recommendations for Integrated Field Crop
Management. Resource Center, Cornell University, Ithaca, NY.
Costa, R.H.R., A.S.L. Bavaresco, W. Medri, and L.S. Philippi. 2000. Tertiary treatment of piggery
wastes in water hyacinth ponds. Water Science and Technology 42(10-11):211-214.
Costa, R.D., C.R.G. Tavares, and E.S. Cossich. 2007. Stabilization of swine wastes by
anaerobic digestion. Environmental Tec/?no/ogy28:1145-1151.
Dabney, S.M., J.A. Delgado, and D.W. Reeves. 2001. Using winter cover crops to improve soil
and water quality. Communications in Soil Science and Plant Analysis 32(7&8):1221-1250.
Dabney, S.M., Y. Yuan, and R.L. Bingner. 2001. Evaluation of Best Management Practices
(BMPs) in the Mississippi Delta MSEA. Abstracts of Papers American Chemical Society
222(1-2):AGRO117.
Das, K.C., M.Y. Minkara, N.D. Melear, and E.W. Tollner. 2002. Effect of poultry litter
amendment on hatchery waste composting. Journal of Applied Poultry Research
11(3):282-290.
Dauden, A., D. Quilez, and M.V. Vera. 2004. Pig slurry application and irrigation effects on
nitrate leaching in Mediterranean soil lysimeters. Journal of Environmental Quality
33:2290-2295.
Daverede, I.C., A.N. Kravchenko, R.G. Hoeft, E.D. Nafziger, D.G. Bullock, J.J. Warren, LC.
Gonzini. 2004. Phosphorus runoff from incorporated and surface-applied liquid swine
manure and phosphorus fertilizer. Journal of Environmental Quality 33:1535-1544.
Dayton, E.A., and NT. Basta. 2005. Use of drinking water residuals as a potential best
management practice to reduce phosphorus risk index scores. Journal of Environmental
Quality 34:2112-2117.
Dayton, E.A., NT. Basta, C.A. Jakober, and J.A. Hattey. 2003. Using treatment residuals to
reduce phosphorus in agricultural runoff. Journal American Water Works Association
95:151-158.
Dean, J.E., and R.R. Weil. 2009. Brassica Cover crops for nitrogen retention in the Mid-Atlantic
coastal plain. Journal of Environmental Quality 38:520-528
Chapter 2. Agriculture 2-153
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
Demirer, G.N., and S. Chen. 2005. Two-phase anaerobic digestion of unscreened dairy manure.
Process Biochemistry 40(11):3542-3549.
Deng, L.-W., P. Zheng, S. Li, X. Sun, and Y. Tang. 2005. Performance improvement of
sequencing batch reactor (SBR) treating digested piggery wastewater by addition of raw
wastewater. Huanjing Kexue 26(6): 105-109.
DeWolfe, J. 2006. Water Residuals to Reduce Soil Phosphorus. AWWA Research Foundation,
Am. Waterworks Assoc., Denver, CO.
Do, J.C., I.H. Choi, and K.H. Nahm. 2005. Effects of chemically amended litter on broiler
performances, atmospheric ammonia concentration, and phosphorus solubility in litter.
Poultry Science 84(5):679-686.
Dosskey, M.G., D.E. Eisenhauer, and M.J. Helmers. 2005. Establishing conservation buffers
using precision information. Journal of Soil and Water Conservation 60(6):349-354.
Dosskey, M.G., K.D. Hoagland, and J.R. Brandle. 2007. Change in filter strip performance over
ten years. Journal of Soil and Water Conservation 62(1):21-32.
Dosskey, M.G., M.J. Helmers, and D.E. Eisenhauer. 2006. An approach for using soil surveys to
guide the placement of water quality buffers. Journal of Soil and Water Conservation
61(6):344-354.
Dosskey, M.G., M.J. Helmers, and D.E. Eisenhauer. 2008. A design aid for determining width of
filter strips. Journal of Soil and Water Conservation 63(4):232-241.
Dou, Z., G.Y. Zhang, W.L. Stout, and J.D. Toth. 2003. Efficacy of alum and coal combustion by-
products in stabilizing manure phosphorus. Journal of Environmental Quality
32(4):1490-1497.
Drury, C.F., C.S. Tan, J.D. Gaynor, T.O. Oloya, and T.W. Welacky. 1996. Influence of
Controlled Drainage-Subirrigation on Surface and Tile Drainage Nitrate Loss. Journal of
Environmental Quality 25:8.
Drury, C.F., C.S. Tan, W.D. Reynolds, T.W. Welacky, T.O. Oloya, and J.D. Gaynor. 2009.
Managing Tile Drainage, Subirrigation, and Nitrogen Fertilization to Enhance Crop Yields
and Reduce Nitrate Loss. Journal of Environmental Quality 38(3): 1193-1204.
Dunne, E.J., K.A. McKee, M.W. Clark, S. Grunwald, and K.R. Reddy. 2006. Phosphorus in
agricultural ditch soil and potential implications for water quality. Conference on Managing
Agricultural Drainage Ditches for Water Quality Protection, College Pk, MD, Soil Water
Conservation Soc.
2-154 Chapter 2. Agriculture
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
Dunne, E.J., N. Culleton, G.O'Donovan, and R. Harrington. 2004. Constructed wetlands to
retain contaminants and nutrients, specifically phosphorus from farmyard dirty water in
Southeast Ireland, International Symposium on Nutrient Management in Agricultural
Watersheds - A Wetlands Solution, Wexford, Ireland, Wageningen Academic Publishers,
pp. 144-156.
Dunne, E.J., N. Culleton, G. O'Donovan, R. Harrington, and A.E. Olsen. 2005. An integrated
constructed wetland to treat contaminants and nutrients from dairy farmyard dirty water.
Ecological Engineering 24(3):221-234.
Ebelhar, S.A., C.D. Hart, J.D. Hernandez, L.E. Paul, and J.J. Warren. 2009. Evaluation of New
Nitrogen Fertilizer Technologies for Corn. Illinois Fertilizer Conference Proceedings.
. Accessed on April 24, 2010.
Ebeling, A.M., L.G. Bundy, J.M. Powell, and T.W. Andraski. 2002. Dairy diet phosphorus effects
on phosphorus losses in runoff from land-applied manure. So/7 Science Society of America
Journal 66:284-291.
Edgerton, B.D., D. McNevin, C.H. Wong, P. Menoud, J.P. Barford, and C.A. Mitchell. 2000.
Strategies for dealing with piggery effluent in Australia: the sequencing batch reactor as a
solution. Water Science and Technology 41(1): 123-126.
El Hafiane, F., A. Rami, and B. El Hamouri. 2003. Mechanisms of nitrogen and phosphorus
removal in a high rate algal pond. Revue des Sciences de I'Eau 16(2): 157-172.
Elliott, H.A., G.A. O'Connor, P. Lu, and S. Brinton. 2002. Influence of water treatment residuals
on phosphorus solubility and leaching. Journal of Environmental Quality 31:1362-1369.
Emiola, A., O. Akinremi, B. Slominski, and C.M. Nyachoti. 2009. Nutrient utilization and manure
P excretion in growing pigs fed corn-barley-soybean based diets supplemented with
microbial phytase. Animal Science Journal 80(1): 19-26.
Entry, J.A. and R.E. Sojka. 2000. The efficacy of polyacrylamide and related compounds to
remove microorganisms and nutrients from animal wastewater. Journal of Environmental
Qtya/rty29(6):1905-1914.
Evans, R., and W. Skaggs. 1996. Operating controlled drainage and subirrigation systems.
North Carolina Cooperative Extension Service Publication Number: AG 356 8.
Evans, R., J.W. Gilliam, and W. Skaggs. 1996. Controlled drainage management guidelines for
improving drainage water quality. North Carolina Cooperative Extension Service
Publication Number: AG 443: 18.
Chapter 2. Agriculture 2-155
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
Evans, R., W. Skaggs, and R.E. Sneed. 1996. Economics of controlled drainage and
subirrigation systems. North Carolina Cooperative Extension Service Publication Number:
AG39716.
Fajardo, J.J., J.W. Bauder, and S.D. Cash. 2001. Managing nitrate and bacteria in runoff from
livestock confinement areas with vegetative filter strips. Journal of Soil and Water
Conservation 56(3): 185-191.
Fausey, N. 2005. Drainage Management for Humid Regions. International Agricultural
Engineering Journal 14(4):6.
Favaretto, N., L.D. Norton, B.C. Joern, and S.M. Brouder. 2006. Gypsum Amendment and
Exchangeable Calcium and Magnesium Affecting Phosphorus and Nitrogen in Runoff. So/7
Science Society of America Journal 70:1788-1796
Federal Leadership Committee for the Chesapeake Bay. 2009. Draft strategy for protecting and
restoring the Chesapeake Bay.
. Accessed
February 21, 2010.
Feyereisen, G.W., Bryant, R.B., Penn, C., Allen, A.L. 2008. Filtration of agricultural non-point
source phosphorus pollution with industrial materials. Presented at the 2008 Beneficial
Use of Industrial Materials Summit, Denver, CO, March 31-April 2, 2008.
Fisher, J. and M.C. Acreman. 2004. Wetland nutrient removal: a review of the evidence.
Hydrology and Earth System Sciences 8(4):673-685.
Flanagan, D.C., L.D. Norton, J.R. Peterson, and K. Chaudhari. 2003. Using polyacrylamide to
control erosion on agricultural and disturbed soils in rainfed areas. Journal of Soil and
Water Conservation 58(5):301-311.
Fleisher, Z., and J. Hagin. 1981. Lowering ammonia volatilization losses from urea by activation
of the nitrification process. Fertilizer Research 2:101-107.
Frankenberger, J., E. Kladivko, G. Sands, D. Jaynes, N. Fausey, M. Helmers, R. Cooke, J.
Strock, K.N., and L. Brown. 2006. Questions and Answers About Drainage Water
Management for the Midwest. Purdue University Water Quality Program, Purdue
Extension Knowledge to Go WQ-44: 8.
Franklin, D.H., M.L. Cabrera, H.L. Byers, M.K. Matthews, J.G. Andrae, D.E. Radcliffe, M.A.
McCann, H.A. Kuykendall, C.S. Hoveland, and V.H. Calvert. 2009. Impact of water
troughs on cattle use of riparian zones in the Georgia Piedmont in the United States.
Journal of Animal Science 87(6):2151-2159.
2-156 Chapter 2. Agriculture
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
Franklin, D.H., M.L. Cabrera, and V.H. Calvert. 2006. Fertilizer source and soil aeration effects
on runoff volume and quality. So/7 Science Society of America Journal 70:84-89.
Franklin, D.H., M.L. Cabrera, L.T. West, V.H. Calvert, and J.A. Rema. 2007. Aerating
grasslands: Effects on runoff and phosphorus losses from applied broiler litter. Journal of
Environmental Quality 36:208-215.
Franzluebbers, A.J. 2005. Integrated crop-livestock systems in the southeastern USA.
Symposium on Integrated Crop-Livestock Systems for Profit and Sustainability, Salt Lake
City, UT, American Society of Agronomy.
Franzluebbers, A.J., and J. A. Stuedemann. 2008. Soil physical responses to cattle grazing
cover crops under conventional and no tillage in the Southern Piedmont USA. So/7 &
Tillage Research 100(1-2): 141-153.
Gallimore, L.E., NT. Basta, D.E. Storm, M.E. Payton, R.H. Huhnke, and M.D. Smolen. 1999.
Water treatment residual to reduce nutrients in surface runoff from agricultural land.
Journal of Environmental Quality 28:1474-1478.
Garcia, M.C., A.A. Szogi, M.B. Vanotti, J.P. Chastain, and P.O. Millner. 2009. Enhanced solid-
liquid separation of dairy manure with natural flocculants. Bioresource Technology
100(22): 5417-5423.
Gardenas, A.I., J.W. Hopmans, B.R. Hanson, and J. Simunek. 2005. Two-dimensional modeling
of nitrate leaching for various fertigation scenarios under micro-irrigation. Agricultural
Water Management 74:219-242.
Garrett, H.E., M.S. Kerley, K.P. Ladyman, W.D. Walter, L.D. Godsey, J.W. Van Sambeek, and
O.K. Brauer. 2004. Hardwood silvopasture management in North America. Agroforestry
Systems 61-2(1):21-33.
Garrison, A.V., and T.L. Richard. 2005. Methane and manure: Feasibility analysis of price and
policy alternatives. Transactions of the ASAE 48(3):1287-1294.
Gaynor, J.D., and W.I. Findlay. 1995. Soil and phosphorus loss from conservation and
conventional tillage in corn production. Journal of Environmental Quality 24(4):734-741.
Geohring, L.D., O.V. McHugh, M.T. Walter, T.S. Steenhuis, M.S. Akhtar, and M.F. Walter. 2001.
Phosphorus transport into subsurface drains by macropores after manure applications:
implications for best manure management practices. So/7 Science 166:896-910.
Ghadiri, H., C.W. Rose, and W.L. Hogarth. 2001. The influence of grass and porous barrier strips
on runoff hydrology and sediment transport. Transactions of the X\SX\£44(2):259-268.
Chapter 2. Agriculture 2-157
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
Gharabaghi, B., R.P. Rudra, H.R. Whiteley, and W.T. Dickinson. 2001. Sediment-Removal
Efficiency of Vegetative Filter Strips. 2001ASAE Annual International Meeting.
Sacramento, California, USA.
Ghebremichael, L.T., P.E. Cerosaletti, T.L. Veith, C.A. Rotz, J.M. Hamlett, and W.J. Gburek.
2007. Economic and phosphorus-related effects of precision feeding and forage
management at a farm scale. Journal of Dairy Science 90:3700-3715.
Giasson, E., R.B. Bryant, and N.L. Bills. 2003. Optimization of phosphorus index and costs of
manure management on a New York dairy farm. Agronomy Journal 95:987-993.
Gibbs, P.A., R.J. Parkinson, T.H. Misselbrook, and S. Burchett. 2002. Environmental impacts of
cattle manure composting. Microbiology of Composting 445-456.
Gilley, J.E., B. Eghball, L.A. Kramer, and T.B. Moorman. 2000. Narrow grass hedge effects on
runoff and soil loss. Journal of Soil and Water Conservation 55(2): 190-196.
Gilley, J.E., E.D. Berry, R.A. Eigenberg, D.B. Marx, and B.L. Woodbury. 2008. Spatial variations
in nutrient and microbial transport from feedlot surfaces. Transactions of the ASABE
51(2):675-684.
Gilliam, J.W., R.W. Skaggs, and S.B. Weed. 1979. Drainage Control to Diminish Nitrate Loss
from Agricultural Fields. Journal of Environmental Quality 8:6.
Giroux, M., and R. Royer. 2007. Long term effects of phosphate applications on yields, evolution
of P soil test, saturation, and solubility in two very rich soils. Agrosolutions 18:17-24.
Gold, M.V., and R.S. Thompson. 2009. Alternative crops & enterprises for small farm
diversification. USDA-ARS, National Agricultural Library
and
. Accessed February 21, 2010.
Gonzalez, C., J. Marciniak, S. Villaverde, C. Leon, P.A. Garcia, and R. Munoz. 2008. Efficient
nutrient removal from swine manure in a tubular biofilm photo-bioreactor using algae-
bacteria consortia. Water Science and Technology 58(1):95-102.
Goos, R. J., and A.P. Cruz. 1999. Effect of ammonium sulfate pretreatment on ammonia
volatilization after urea fertilization. Communications in Soil Science and Plant Analysis
30:1325-1336.
Graham, H., P.M. Simmins, and J. Sands. 2003. Reducing environmental pollution using animal
feed enzymes. Communications in Agricultural and Applied Biological Sciences 68:285-289.
2-158 Chapter 2. Agriculture
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
Grandhi, R.R. 2001. Effect of supplemental phytase and ideal dietary amino acid ratios in
covered and hulless-barley-based diets on pig performance and excretion of phosphorus
and nitrogen in manure. Canadian Journal of Animal Science 81:115-124.
Grigg, B.C., L.M. Southwick, J.L. Fouss, and T.S. Kornecki. 2003. Drainage system impacts on
surface runoff, nitrate loss, and crop yield on a southern alluvial soil. Transactions of the
X\SX\£46(6):1531-1537.
Gu, B.H. 2008. Phosphorus removal in small constructed wetlands dominated by submersed
aquatic vegetation in South Florida, USA. Journal of Plant Ecology-UK'\('\)\B7-74.
Gu, B.H., and T. Dreschel. 2008. Effects of plant community and phosphorus loading rate on
constructed wetland performance in Florida, USA. H/ef/ancfs28(1):81-91.
Gungor-Demirci, G., and G.N. Demirer. 2004. Effect of initial COD concentration, nutrient
addition, temperature and microbial acclimation on anaerobic treatability of broiler and
cattle manure. Bioresource Technology 93(2): 109-117.
Quo, M.X., N. Tongtavee, and M. Labreveux. 2009. Nutrient dynamics of field-weathered
Delmarva poultry litter: implications for land application. Biology and Fertility of Soils
45:829-838.
Habersack, M.J. 2002. Evaluation of nutrient and pathogen losses from various poultry litter
storage methods. MS Thesis, Virginia Tech, Blacksburg, VA
. Accessed April 14, 2010.
Hansen, E.M., J. Djurhuus, and K. Kristensen. 2000. Nitrate leaching as affected by introduction
or discontinuation of cover crop use. Journal of Environmental Quality 29(4): 1110-1116.
Harmel, D., S. Potter, P. Casebolt, K. Reckhow, C. Green, and R. Haney. 2006. Compilation of
measured nutrient load data for agricultural land uses in the United States. Journal of the
American Water Resources Association 42(5): 1163-1178.
Harmel, D., S. Qian, K. Reckhow, and P. Casebolt. 2008. The MANAGE Database: Nutrient
Load and Site Characteristic Updates and Runoff Concentration Data. Journal of
Environmental Quality 37(6):2403-2406.
Harmel, R.D., A.L. Kenimer, S.W. Searcy, and H.A. Torbert. 2004. Runoff water quality impact
of variable rate sidedress nitrogen application. Journal of Precision Agriculture 5:247-261.
Harrington, R., and R. Mclnnes. 2009. Integrated Constructed Wetlands (ICW) for livestock
wastewater management. Bioresource Technology 100(22):5498-5505.
Chapter 2. Agriculture 2-159
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
Hartwig, N.L., and H.U. Ammon. 2002. Cover crops and living mulches. Weed Science
50:688-699.
Haustein, G.K., T.C. Daniel, D.M. Miller, P.A. Moore, and R.W. McNew. 2000. Aluminum-
containing residuals influence high-phosphorus soils and runoff water quality. Journal of
Environmental Quality 29:1954-1959.
He, B.J., Y. Zhang, T.L. Funk, G.L. Riskowski, and Y. Yin. 2000. Thermochemical conversion of
swine manure: An alternative process for waste treatment and renewable energy
production. Transactions of the ASAE 43(6): 1827-1833.
Healy, M.G., M. Rodgers, and J. Mulqueen. 2004. Recirculating sand filters for treatment of
synthetic dairy parlor washings. Journal of Environmental Quality 33(2):713-718.
Healy, M.G., M. Rodgers, and J. Mulqueen. 2007. Performance of a stratified sand filter in
removal of chemical oxygen demand, total suspended solids and ammonia nitrogen from
high-strength wastewaters. Journal of Environmental Management 83(4):409-415.
Herrera, J.M., and M. Liedgens. 2009. Leaching and utilization of nitrogen during a spring wheat
catch crop succession. Journal of Environmental Quality 38(4):1410-1419.
Hebbar, S.S., B.K. Ramachandrappa, H.V. Nanjappa, and M. Prabhakar. 2004. Studies on NPK
drip fertigation in field grown tomato (Lycopersicon esculentum Mill.). European Journal of
Agronomy 21:117-127.
Hettiarachchi, G.M., E. Lombi, M.J. Mclaughlin, D. Chittleborough, and P. Self. 2006. Density
change around phosphorus granules and fluid bands in a calcareous soil. So/7 Science
Society of America Journal 70:960-966.
Hirschi, M., R. Frazee, G. Czapar, and D. Peterson. 1997. 60 Ways Farmers Can Protect
Surface Water, North Central Regional Extension Publication 589, Information Technology
and Communication Services, College of Agricultural, Consumer and Environmental
Sciences, University of Illinois, Urbana-Champaign, IL, 317 pp.
Hirschi, M.C., F.W. Simmons, D. Peterson, E. Giles. 1993. 50 Ways Farmers Can Protect their
Groundwater. Cooperative Extension Service. University of Illinois, Urbana, IL.
Hoffmann, C.C., C. Kjaergaard, J. Uusi-Kamppa, H.C.B. Hansen, and B. Kronvang. 2009.
Phosphorus Retention in Riparian Buffers: Review of Their Efficiency. Journal of
Environmental Quality 38(5): 1942-1955.
Holloway, R., B. Frischke, A. Frischke, D. Brace, E. Lombi, M. McLaughlin, and R. Armstrong.
2006. Fluids excel over granular on Australian calcareous soils. Fluid Journal 14:14-16.
2-160 Chapter 2. Agriculture
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
Hook, P.B. 2003. Sediment retention in rangeland riparian buffers. Journal of Environmental
Quality 32(3): 1130-1137.
Hoyt, G.D. 2005 Winter Annual Cover Crops. SoilFacts. North Carolina State University.
.
Accessed April 12, 2010.
Hubbard, R.K., G.L. Newton, and J.M. Ruter. 2007. A farm-scale test of nitrogen assimilation by
vegetated buffer systems receiving swine lagoon effluent by overland flow. Transactions of
the ASABE 50(1):53-64.
Hunt, P.G. and M.E. Poach. 2002. State of the art for animal wastewater treatment in
constructed wetlands. Water Science and Technology 44(11-12): 19-25.
Hunt, P.G., K.C. Stone, T.A. Matheny, M.E. Poach, M.B. Vanotti, and T.F. Ducey. 2009.
Denitrification of nitrified and non-nitrified swine lagoon wastewater in the suspended
sludge layer of treatment wetlands. Ecological Engineering 35(10):1514-1522.
Hyde, J.E., and T.F. Morris. 2000. Phosphorus availability in soils amended with dewatered
water treatment residual and metal concentrations with time in residual. Journal of
Environmental Quality 29:1896-1904.
James, E., P. Kleinman, T. Veith, R. Stedman, and A. Sharpley. 2007. Phosphorus contributions
from pastured dairy cattle to streams of the Cannonsville Watershed, New York. Journal of
Soil and Water Conservation 62(1):40^7.
Jaynes, D.B., T.C. Kaspar, T.B. Moorman, and T.B. Parkin. 2004. Potential methods for
reducing nitrate losses in artificially drained field. Drainage VIII Proceedings of the Eighth
International Symposium, Sacramento, CA.
Jin, C.X., and M.J.M. Romkens. 2001. Experimental studies of factors in determining sediment
trapping in vegetative filter strips. Transactions of the ASAE 44(2):277-288.
Jin, C.X., S.M. Dabney, and M.J.M. Romkens. 2002. Trapped mulch increases sediment removal
by vegetative filter strips: A flume study. Transactions of the ASAE 45(4):929-939.
Johnson, J.T., R.D. Lee, and R.L. Stewart. 1997. Pastures in Georgia. Bulletin 573, Cooperative
Extension Service, College of Agricultural & Environmental Sciences, University of
Georgia, Athens, GA, 31 pp.
Jones, R.M. and S.P. Brown. 2000. Chemical and settling treatment of dairy wastewater for
solids separation and phosphorus removal. Animal, Agricultural and Food Processing
Wastes: 132-141.
Chapter 2. Agriculture 2-161
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
Jordan, I.E., D.F. Whigham, K.H. Hofmockel, and M.A. Pittek. 2003. Nutrient and sediment
removal by a restored wetland receiving agricultural runoff. Journal of Environmental
Quality 32(4): 1534-1547.
Kaiser, D.E., Mallarino, A.P., Haq, M.U., Allen, B.L. 2009. Runoff Phosphorus Loss Immediately
after Poultry Manure Application as Influenced by the Application Rate and Tillage. Journal
of Environmental Quality 38:299-308
Kalita, P.K., and R.S. Kanwar. 1993. Effect of Water-table Management Practices on the
Transport of Nitrate-N to Shallow Groundwater. Transactions of the ASAE 36(2):413-422.
Kalita, P.K., R. A.C. Cooke, S.M. Anderson, M.C. Hirschi, and J.K. Mitchell. 2007. Subsurface
Drainage and Water Quality: The Illinois Experience. Transactions of the ASABE
50(5):1651-1656.
Kallenbach, R.L., M.S. Kerley, and G.J. Bishop-Hurley. 2006. Cumulative forage production,
forage quality and livestock performance from an annual ryegrass and cereal rye mixture
in a pine walnut silvopasture. Agroforestry Systems 66(1):43-53.
Kaspar, T.C., D.B. Jaynes, T.B. Parkin, and T.B. Moorman. 2007. Rye Cover Crop and
Gamagrass Strip Effects on NO3 Concentration and Load in Tile Drainage. Journal of
Environmental Quality 36(5): 1503-1511.
Kemper, N.P., and H.L. Goodwin. 2009. Feasibility and production costs of composting breeder
and pullet litter with eggshell waste. Journal of Applied Poultry Research 18(2): 172-184.
Khose, K.K., Ranade, A.S., Kadam, M.M., Jagatap, S.K., Gole, M.A. 2003. Effect of phytase
supplementation on performance of broilers fed low phosphorus diet. Indian Journal of
Poultry Science 38:288-290.
Kim, Y.-J., L.D. Geohring, and T.S. Steenhuis. 2003. Phosphorus removal in vegetative filter
strips receiving milkhouse wastewater and barnyard runoff. 2003 ASAE International
Meeting. Las Vegas, NV.
King, K.W., and H.A. Torbert. 2007. Nitrate and ammonium losses from surface-applied organic
and inorganic fertilizers. Journal of Agricultural Science 145:385-393.
Kladivko, E.J., J.R. Frankenberger, D.B. Jaynes, D.W. Meek, B.J. Jenkinson, and N.R. Fausey.
2004. Nitrate leaching to subsurface drains as affected by drain spacing and changes in
crop production system. Journal of Environmental Quality 33:11.
Kleinman, P.J.A., A.N. Sharpley, L.S. Saporito, A.R. Buda, and R.B. Bryant. 2009. Application of
manure to no-till soils: phosphorus losses by sub-surface and surface pathways. Nutrient
Cycling in Agroecosystems 84:215-227.
2-162 Chapter 2. Agriculture
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
Klik, A., A.S. Zartl, and J. Rosner. 2001. Tillage effects on soil erosion, nutrient, and pesticide
transport. International Symposium on Soil Erosion Research for the 21st Century,
Honolulu, HI, Amer Soc Agr Engineers.
Knowlton, K.F., J.S. Radcliffe, C.L. Novak, and D.A. Emmerson. 2004. Animal management to
reduce phosphorus losses to the environment. Journal of Animal Science 82 E-SuppI,
E173-195.
Knox, A.K., R.A. Dahgren, K.W. Tate, and E.R. Atwill. 2008. Efficacy of natural wetlands to
retain nutrient, sediment and microbial pollutants. Journal of Environmental Quality
37(5): 1837-1846.
Koelsch, R.K., J.C. Lorimor, and K.R. Mankin. 2006. Vegetative treatment systems for
management of open lot runoff: a review of the literature. Applied Engineering in
Agriculture 22(1):141-153.
Koenig, R.T., M.D. Palmer, F.D. Miner, B.E. Miller, and J.D. Harrison. 2005. Chemical
amendments and process controls to reduce ammonia volatilization during in-house
composting. Compost Science & Utilization 13(2):141-149.
Kovacic, D.A., M.B. David, L.E. Gentry, K.M. Starks, and R.A. Cooke. 2000. Effectiveness of
constructed wetlands in reducing nitrogen and phosphorus export from agricultural tile
drainage. Journal of Environmental Quality 29(4): 1262-1274.
Kovacic, D.A., R.M. Twait, M.P. Wallace, and J.M. Bowling. 2005. Use of created wetlands to
improve water quality in the Midwest - Lake Bloomington case study. 5th Annual
Conference of the American-Ecological-Engineering-Society, Columbus, OH, Elsevier
Science Bv.
Kovzelove, C*., T. Simpson, and R. Korcak. 2010 Quantification and
Implications of Surplus Phosphorus and Manure in Major Animal Production
Regions of Maryland, Pennsylvania, and Virginia. Water Stewardship, Inc., Annapolis, MD.
* On detail from U.S. EPA
.
Kroger, R., M.M. Holland, M.T. Moore, and C.M. Cooper. 2007. Hydrological variability and
agricultural drainage ditch inorganic nitrogen reduction capacity. Journal of Environmental
Quality 36(6): 1646-1652.
Kumar, P., and R.K. Aggarwal. 1988. Reduction of ammonia volatilization from urea by rapid
nitrification. Arid Soil Research and Rehabilitation 2:131-138.
Ladha, J.K., H. Pathak, T.J. Krupnik, J. Six, and C. van Kessel. 2005. Efficiency of fertilizer
nitrogen in cereal production: retrospects and prospects. /Advances in Agronomy 87:85-156.
Chapter 2. Agriculture 2-163
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
Lansing, S., R.B. Botero, and J.F. Martin. 2008a. Waste treatment and biogas quality in small-
scale agricultural digesters. Bioresource Technology 99(13):5881-5890.
Lansing, S., J. Viquez, H. Martinez, R. Botero, and J. Martin. 2008b. Quantifying electricity
generation and waste transformations in a low-cost, plug-flow anaerobic digestion system.
Ecological Engineering 34(4):332-348.
Lara-Cabezas, W.A.R., P.C.O. Trivelin, and A.E. Boaretto. 1992. Effect of granule size and N/S
ratio of urea surface applied on ammonia volatilization under different initial soil moisture
content. Revista Brasileira de Ciencia do Solo 16:409-413 (in Portuguese).
Lara-Cabezas, W.A.R., G.H. Korndorfer, and S.A. Motta. 1997. NH3 volatilization in corn crop. I.
Effect of irrigation and partial substitution of urea by ammonium sulfate. Revista Brasileira
de Ciencia do Solo 21:481-487.
Larney, F.J., and X.Y. Hao. 2007. A review of composting as a management alternative for beef
cattle feedlot manure in southern Alberta, Canada. Bioresource Technology 98:3221-3227.
Layden, N.M., H.G. Kelly, D.S. Mavinic, R. Moles, and J. Bartlett. 2007. Autothermal
thermophilic aerobic digestion (ATAD) - Part II: Review of research and full-scale
operating experiences. Journal of Environmental Engineering and Science 6(6):679-690.
Lee, B.H., and W.C. Song. 2006. High concentration of ozone application by the DAF
(Dissolved Air Flotation) system to treat livestock wastewater. Water Pollution VIII:
Modelling, Monitoring and Management 95:561-569.
Lee, C.Y., C.C. Lee, F.Y. Lee, S.K. Tseng, and C.J. Liao. 2004. Performance of subsurface flow
constructed wetland taking pretreated swine effluent under heavy loads. Bioresource
Technology 92(2): 173-179.
Lee, K.H., T.M. Isenhart, R.C. Schultz, and S.K. Mickelson. 2000. Multispecies riparian buffers
trap sediment and nutrients during rainfall simulations. Journal of Environmental Quality
29(4):1200-1205.
Lee, K.H., T.M. Isenhart, and R.C. Schultz. 2003. Sediment and nutrient removal in an
established multi-species riparian buffer. Journal of Soil and Water Conservation 58(1):1-8.
Lefcourt, A.M., and J.J. Meisinger. 2001. Effect of adding alum or zeolite to dairy slurry on
ammonia volatilization and chemical composition. Journal of Dairy Science
84(8):1814-1821.
Lewis, T.W., and J.C. Makarewicz. 2009. Winter application of manure on an agricultural
watershed and its impact on downstream nutrient fluxes. Journal of Great Lakes Research
35:43^9.
2-164 Chapter 2. Agriculture
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
Leytem, A.B., Plumstead, P.W., Maguire, R.O., Kwanyuen, P., Burton, J.W., Brake, J. 2008.
Interaction of calcium and phytate in broiler diets. 2. Effects on total and soluble
phosphorus excretion. Poultry Science 87:459-467.
Lin, C.H., R.N. Lerch, H.E. Garrett, D. Jordan, and M.F. George. 2007. Ability of forage grasses
exposed to atrazine and isoxaflutole to reduce nutrient levels in soils and shallow
groundwater. Communications in Soil Science and Plant Analysis 38(9-10): 1119-1136.
Line, D.E. 2003. Changes in a stream's physical and biological conditions following livestock
exclusion. Transactions of the ASAE 46(2):287-293.
Line, D.E., W.A. Harman, G.D. Jennings, E.J. Thompson, and D.L. Osmond. 2000. Nonpoint-
source pollutant load reductions associated with livestock exclusion. Journal of
Environmental Quality 29(6): 1882-1890.
Liu, X.M., X.Y. Mang, and M.H. Zhang. 2008. Major factors influencing the efficacy of vegetated
buffers on sediment trapping: A review and analysis. Journal of Environmental Quality
37(5): 1667-1674.
Loeffler, P.A., and T.A. van Kempen. 2003. Evaluation of ammonia recovery waste treatment for
swine urine. Animal, Agricultural and Food Processing Wastes Ix, Proceedings: 568-575.
Lombi, E., M. J. McLaughlin, C. Johnson, R. D. Armstrong, and R. E. Holloway. 2004. Mobility
and lability of phosphorus from granular and fluid monoammonium phosphate differs in a
calcareous soil. So/7 Science Society of America Journal 68:682-689.
Loria, E.R., and J.E. Sawyer. 2005. Extractable soil phosphorus and inorganic nitrogen following
application of raw and anaerobically digested swine manure. Agronomy Journal
97:879-885.
Loria, E.R., J.E. Sawyer, D.W. Barker, J.P. Lundvall, and J.C. Lorimor. 2007. Use of
anaerobically digested swine manure as a nitrogen source in corn production. Agronomy
Journal 99:1119-1129.
Lu, J.B., Z.H. Fu, and Z.Z. Yin. 2008. Performance of a water hyacinth (Eichhornia crassipes)
system in the treatment of wastewater from a duck farm and the effects of using water
hyacinth as duck feed. Journal of Environmental Sciences-China 20(5):513-519.
Lu, L, S.A. Zhang, H. Li, Z.D. Wang, J.J. Li, Z.J. Zhang, and J. Zhu. 2009. A reformed SBR
technology integrated with two-step feeding and low-intensity aeration for swine
wastewater treatment. Environmental Tec/?no/ogy30(3):251-260.
Lue, L., Z. Wang, S. Zhang, and Z. Zhang. 2008. Denitrifying phosphorus-accumulating SBR
combined with low-intensity aeration technology for piggery wastewater treatment,
Huanjing Kexue 29(7): 1884-1889.
Chapter 2. Agriculture 2-165
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
Lyons, J., B.M. Weigel, L.K. Paine, and D.J. Undersander. 2000. Influence of intensive rotational
grazing on bank erosion, fish habitat quality, and fish communities in southwestern
Wisconsin trout streams. Journal of Soil and Water Conservation 55(3):271-276.
Ma, B. 2007. Improving nitrogen use efficiency with sidedressed fertilizer nitrogen on farmer's
corn fields. Paper presented at the annual meeting of the Soil and Water Conservation
Society, January 24, 2010, Tampa, Florida.
Magner, J.A., B. Vondracek, and K.N. Brooks. 2008. Grazed riparian management and stream
channel response in southeastern Minnesota (USA) streams. Environmental Management
42(3): 377-390.
Maguire, R.O., D.A. Grouse, and S.C. Hodges. 2007. Diet modification to reduce phosphorus
surpluses: A mass balance approach. Journal of Environmental Quality 36:1235-1240.
Maguire, R.O., Z. Dou, Z., Sims, J. Brake, and B.C. Joern. 2005. Dietary strategies for reduced
phosphorus excretion and improved water quality. Journal of Environmental Quality
34:2093-2103.
Maguire, R.O., G.L. Mullins, and M. Brosius. 2008. Evaluating long-term nitrogen- versus
phosphorus-based nutrient management of poultry litter. Journal of Environmental Quality
37:1810-1816.
Mankin, K.R., and C.D. Ikenberry 2004. Batch reactor unvegetated wetland performance in
treating dairy wastewater. Journal of the American Water Resources Association
40(6): 1527-1535.
Mankin, K.R., and C.G. Okoren. 2003. Field evaluation of bacteria removal in a VFS. 2003
ASAE Annual International Meeting. Las Vegas, NV.
Mankin, K.R., D.M. Ngandu, C.J. Barden, S.L. Hutchinson, and W.A. Geyer. 2007. Grass-shrub
riparian buffer removal of sediment, phosphorus, and nitrogen from simulated runoff.
Journal of the American Water Resources Association 43(5):1108-1116.
Mankin, K.R., P.L. Barnes, J.P. Harner, P.K. Kalita, and J.E. Boyer. 2006. Field evaluation of
vegetative filter effectiveness and runoff quality from unstocked feedlots. Journal of Soil
and Water Conservation 61:209-217.
Martinez, J., P. Dabert, S.Barrington, and C. Burton. 2009. Livestock waste treatment systems
for environmental quality, food safety, and sustainability. Bioresource Technology
100(22): 5527-5536
Masse, L, D.I. Masse, and Y. Pellerin. 2007. The use of membranes for the treatment of
manure: a critical literature review. Biosystems Engineering 98(4):371-380.
2-166 Chapter 2. Agriculture
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
McDowell, R.W., A.M. Sharpley, D.B. Beegle, and J.L. 2001. Comparing phosphorus
management strategies at a watershed scale. Journal of Soil and Water Conservation 56,
306-315.
McDowell, R.W., and D.J. Houlbrooke. 2009. Management options to decrease phosphorus and
sediment losses from irrigated cropland grazed by cattle and sheep. So/7 Use and
Management 25(3):224-233.
McFarland, A.M.S., and L.M. Hauck. 2004. Controlling phosphorus in runoff from long term dairy
waste application fields. Journal of the American Water Resources Association 40:1293-
1304.
Meals, D.W. 2004. Water quality improvements following riparian restoration in two Vermont
agricultural watersheds, pp. 81-96 in Lake Champlain: Partnership and Research in the
New Millennium. T. Manley etal., eds. Kluwer Academic/Plenum Publishers.
Meals, D.W., J. Fay, and M. Barsotti. 2007. Effects of water treatment residual addition on
phosphorus in liquid dairy manure. Journal of the American Water Works Association
100(4): 140-150.
Mejia, M.N., and C.A. Mandramootoo. 1998. Improved Water Quality through Water Table
Management in Eastern Canada. Journal of Irrigation and Drainage Engineering
124(2): 116-122.
Melse, R.W., and M. Timmerman. 2009. Sustainable intensive livestock production demands
manure and exhaust air treatment technologies. Bioresource Technology 100(22):5506-
5511.
Merriman, K.R., M.W. Gitau, and I. Chaubey. 2009. Tool for estimating best management
practice effectiveness in Arkansas. Applied Engineering in Agriculture 25(2): 199-213.
Michel, G.A., V.D. Nair, and P.K.R. Nair. 2007. Silvopasture for reducing phosphorus loss from
subtropical sandy soils. Plant and Soil 297:267-276.
Mid-Atlantic Water Program. 2007. Nutrient budgets for the Mid-Atlantic states,
. Accessed February 21, 2010.
Minnesota Department of Agriculture and University of Minnesotat Extension (No date).
Woodchip Bioreactors. Agricultural Drainage Management Coalition,
. Accessed February 21, 2010.
Mitchell, C.C., H.A. Torbert, T.S. Kornecki, and T.W. Tyson. 2007. Temporary storage of poultry
broiler litter. Research Journal of Agronomy 1(4): 129-137.
Chapter 2. Agriculture 2-167
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
Moore, P.A. Jr, T.C. Daniel, and D.R. Edwards. 1999. Reducing phosphorus runoff and
improving poultry production with alum. Poultry Science 78(5):692-698.
Moore, P.A., T.C. Daniel, and D.R. Edwards. 1998. Reducing phosphorus runoff and inhibiting
ammonia loss from poultry manure with aluminum sulfate. OECD Conference on Practical
and Innovative Measures for the Control of Agricultural Phosphorus Losses to Water,
Antrim, North Ireland, American Society of Agronomy.
Moore, P.A., T.C. Daniel, and D.R. Edwards. 2000. Reducing nonpoint source phosphorus
runoff from poultry manure with aluminum sulfate. Biological Resource Management:
Connecting Science and Policy: 117-127.
Morgan, K.T., K.E. Cushman, and S. Sato. 2009. Release mechanisms for slow- and controlled-
release fertilizers and strategies for their use in vegetable production. Horttechnology
19:10-12.
Morrison, L. 2008. Nitrate neutralizes Corn and Soybean Digest March 2008.
Mosier, A.R., J.K. Syers, and J.R. Freney. 2004. Ch. 1-Nitrogen fertilizer: an essential
component of increased food, feed, and fiber production, pp. 3-15. In A.R. Mosier, J.K.
Syers, and J.R. Freney (eds.). Agriculture and the Nitrogen Cycle. Assessing the impacts
and J.R. Freney (eds.). Agriculture and the Nitrogen Cycle. Assessing the impacts of
fertilizer use on food production and the environment. Scientific Committee on Problems of
the Environment (SCOPE). Island Press, Washington, DC.
Mulbry, W., S. Kondrad, C. Pizarro, and E. Kebede-Westhead. 2008. Treatment of dairy manure
effluent using freshwater algae: Algal productivity and recovery of manure nutrients using
pilot-scale algal turf scrubbers. Bioresource Technology 99(17):8137-8142.
Murphy, P.N.C. and R.J. Stevens. 2010. Lime and Gypsum as Source Measures to Decrease
Phosphorus Loss from Soils to Water. Water, Air, and Soil Pollution (in press).
Musser, W., L. Lynch, D. Johnson, N. Wallace, and K. McNew. 1999. Alternative agriculture in
Maryland: a guide to evaluate farm-based enterprises. University of Maryland, Department
of Agricultural and Resource Economics.
. Accessed
February 21, 2010.
Mustafa, A., M. Scholz, R. Harrington, and P. Carroll. 2009. Long-term performance of a
representative integrated constructed wetland treating farmyard runoff. Ecological
Engineering 35(5):779-790.
Nahm, K.H. 2009. Effects of Vitamin D, Citric Acid, and Phytase on Lowering Phosphorus
Levels in the Monogastric Animal Diets, Resulting in Less Environmental Pollution. Critical
Reviews in Environmental Science and Technology 39:521-551.
2-168 Chapter 2. Agriculture
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
Nair, V.D., P.K. R. Nair, R.S. Kalmbacher, and I.V. Ezenwa. 2007. Reducing nutrient loss from
farms through silvopastoral practices in coarse-textured soils of Florida, USA. Ecological
Engineering 29(2): 192-199.
Narvanen, A., H. Jansson, J. Uusi-Kamppa, and P. Perala. 2008. Phosphorus load from equine
critical source areas and its reduction using ferric sulphate. Boreal Environment Research
13(3):265-274.
NCAES (North Carolina Agricultural Extension Service). 1982. Best Management Practices for
Agricultural Nonpoint Source Control III: Sediment. North Carolina Agricultural Extension
Service, in cooperation with EPA and USDA. Raleigh, North Carolina.
Needelman, B.A., D.E. Ruppert, and R.E. Vaughan. 2006. The role of ditch soil formation and
redox biogeochemistry in mitigating nutrient and pollutant losses from agriculture.
Conference on Managing Agricultural Drainage Ditches for Water Quality Protection,
College Pk, MD, Soil Water Conservation Soc.
Newby, L. 2009. Putting producers in the driver's seat. Partners 27(3):2.
Nielsen, R.L. 2001. Optimizing Nitrogen Fertilizer Decisions. Purdue University, West Lafayette,
IN. .
Accessed April 20, 2010.
Nielsen, R.L. 2006. N Loss Mechanisms and Nitrogen Use Efficiency. 2006 Purdue Nitrogen
Management Workshops.
Ng, H.Y.F., C.S. Tan, C.F. Drury, and J.D. Gaynor. 2001. Controlled drainage and subirrigation
influences tile nitrate loss and corn yields in a sandy loam soil in Southwestern Ontario.
Agriculture, Ecosystems and Environment 1758:8.
Novak, J.M., and D.W. Watts. 2004. Increasing the phosphorus sorption capacity of
southeastern Coastal Plain soils using water treatment residuals. So/7 Science 169:206-
214.
Novak, J.M., and D.W. Watts. 2005. An alum-based water treatment residual can reduce
extractable phosphorus concentrations in three phosphorus-enriched coastal plain soils.
Journal of Environmental Quality 34:1820-1827.
Oenema, O., and G.L. Velthof. 1993. Ammonia volatilization from compound nitrogen-sulfur
fertilizer. In Optimization of Plant Nutrition (M.A.C. Fragoso and M.L. van Beusichem,
eds.), pp. 341-349. Kluwer Academic Publishers, Amsterdam.
Oh, I., R.T. Burns, L.B. Mooday, and J. Lee. 2005. Optimization of phosphorus partitioning in
dairy manure using chemical additives with a mechanical solids separator. Transactions of
the ASAE 48(3): 1235-1240.
Chapter 2. Agriculture 2-169
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
Osei, E., B. Du, A. Bekele, L. Hauck, A. Saleh, and A. Tanter. 2008. Impacts of alternative
manure application rates on Texas animal feeding operations: A macro level analysis.
Journal of the American Water Resources Association 44:562-576.
Osmond, D.L, D.M. Butler, N.N. Ranells, M.H. Poore, A. Wossink, and J.T. Green. 2007
Grazing Practices: A Review of the Literature. Technical Bulletin 325-W. North Carolina
State University, North Carolina Agricultural Research Service,.
Owens, L.B., and M.J. Shipitalo. 2009. Runoff quality evaluations of continuous and rotational
over-wintering systems for beef cows. Agriculture Ecosystems & Environment
129(4):482^90.
Patni, N.K., H.R. Toxopeus, and P.Y. Jui. 1985. Bacterial quality of runoff from manured and
unmanured cropland. Transactions of theASAE 28:1871-1877.
Penn, C.J., and R.B. Bryant. 2006. Application of phosphorus sorbing materials to streamside
cattle loafing areas. Journal of Soil and Water Conservation 61(5):303-310.
Penn, C.J., G.L Mullins, L.W. Zelazny, J.G. Warren, and J.M. McGrath. 2004. Surface runoff
losses of phosphorus from Virginia soils amended with turkey manure using phytase and
high available phosphorus corn diets. Journal of Environmental Quality 33:1431-1439.
Pennsylvania State University. 1992. Nonpoint Source Database. Pennsylvania State
University, Department of Agricultural and Biological Engineering, University Park, PA.
Pennsylvania State University. 1997. The Penn State Agronomy Guide, 1997-1998.
Pennsylvania State University, University Park, PA.
Peters, J.M., and NT. Basta. 1996. Reduction of excessive bioavailable phosphorus in soils by
using municipal and industrial wastes. Journal of Environmental Quality 25:1236-1241.
Peterson, J.R., D.C. Flanagan, and J.K. Tishmack. 2002. PAM application method and
electrolyte source effects on plot-scale runoff and erosion. Transactions of the ASAE
45(6): 1859-1867.
Peterson, J.R., D.C. Flanagan, and J.K. Tishmack. 2002. Polyacrylamide and gypsiferous
material effects on runoff and erosion under simulated rainfall. Transactions of the ASAE
45(4):1011-1019.
Poole, T.E. 2004. Cover crops. Fact Sheet 785. Maryland Cooperative Extension,
. Accessed April 15, 2010.
Pote, D.H., T.C. Daniel, A.N. Sharpley, P.A. Moore, D.R. Edwards, and D.J. Nichols. 1996.
Relating extractable soil phosphorus to phosphorus losses in runoff. So/7 Science Society
of America Journal 60:855-859.
2-170 Chapter 2. Agriculture
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
Pote, D.H., W.L. Kingery, G.E. Aiken, F.X. Han, P.A. Moore, and K. Buddington. 2003. Water-
quality effects of incorporating poultry litter into perennial grassland soils. Journal of
Environmental Quality 32:2392-2398.
Pote, D.H., T.R. Way, K.R. Sistani, and P.A. Moore. 2009. Water-quality effects of a
mechanized subsurface-banding technique for applying poultry litter to perennial
grassland. Journal of Environmental Management 90:3534-3539.
Poultry Litter Experts Science Forum. 2008. Can we reach consensus on storage times for
chicken litter? Summary of Chesapeake Research Consortium-Maryland Environmental
Finance Center Science Forum. CRC Publication 08-165.
. Accessed April 12, 2010.
Powers, W., and R. Angel. 2008. A review of the capacity for nutritional strategies to address
environmental challenges in poultry production. Poultry Science 87:1929-1938.
Prado, N., J. Ochoa, and A. Amrane. 2009. Zero Nuisance Piggeries: Long-term performance of
MBR (membrane bioreactor) for dilute swine wastewater treatment using submerged
membrane bioreactor in semi-industrial scale. Water Research 43(6): 1549-1558.
Prantner, S.R., R.S. Kanwar, J.C. Lorimor, and C.H. Pederson. 2001. Soil infiltration and
wetland microcosm treatment of liquid swine manure. Applied Engineering in Agriculture
17(4):483-488.
Puustinen, M., J. Koskiaho, and K. Peltonen. 2005. Influence of cultivation methods on
suspended solids and phosphorus concentrations in surface runoff on clayey sloped fields
in boreal climate. Agriculture Ecosystems & Environment 105(4):565-579.
Qiu, Z., C. Hall, and K. Hale. 2009. Evaluation of cost-effectiveness of conservation buffer
placement strategies in a river basin. Journal of Soil and Water Conservation
64(5):293-302.
Ra, C.S., J.S. Shin, J.S. Oh, I.S. Yuh, and B.J. Hong. 1998. Technology for the optimization of
animal wastewater treatment efficiencies and costs. Korean Journal of Animal Science
40(6):691-700.
Rasse, D.P., J.T. Ritchie, W.R. Peterson, J. Wei, and A.J.M. Smucker. 2000. Rye cover crop
and nitrogen fertilization effects on nitrate leaching in inbred maize fields. Journal of
Environmental Quality 29(1):298-304.
Read, J.J., K.R. Sistani, J.L. Oldham, and G.E. Brink. 2009. Double-cropping annual ryegrass
and bermudagrass to reduce phosphorus levels in soil with history of poultry litter
application. Nutrient Cycling in Agroecosystems 84(1):93-104.
Chapter 2. Agriculture 2-171
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
Reiman, M., D.E. Clay, C.G. Carlson, S.A. Clay, G. Reicks, G., Clay, and D.E. Humburg. 2009.
Manure placement depth impacts on crop yields and N retained in soil. Journal of
Environmental Science and Health Part B-Pesticides Food Contaminants and Agricultural
Wastes 44:76-85.
Risse, L.M., and J.E. Gilley 2000. Manure impacts on runoff and soil loss. Animal, Agricultural
and Food Processing Wastes 578-587.
Ritter, W.F., J. Kulkarni, L.M. Ward, and A. Banerjee. 2003. Potential for reducing nutrient loads
to the Chesapeake Bay with improved livestock waste management, Ninth International
Animal, Agricultural and Food Processing Wastes Proceedings, 12-15 Oct. 2003,
Research Triangle Park, NC, pp. 1-8.
Robertson, W.D., and L.C. Merkley. 2009. In-Stream Bioreactor for Agricultural Nitrate
Treatment. Journal of Environmental Quality 38(1):230-237.
Robertson, W.D., and L.C. Merkley. 2009. In-Stream Bioreactor for Agricultural Nitrate
Treatment. Journal of Environmental Quality 38(1):230-237.
Robertson, W.D., D.W. Blowes, C.J. Ptacek, and J.A. Cherry. 2000. Long-Term Performance of
In Situ Reactive Barriers for Nitrate Remediation. Ground Water 38(5):7'.
Russell, J.R., and L.A. Christensen. 1984. Use and Cost of Soil Conservation and Water Quality
Practices in the Southeast. U.S. Department of Agriculture, Economic Research Service,
Washington, DC.
Sainju, U.M., B.P. Singh, S. Rahman, and V.R. Reddy. 1999. Soil nitrate-nitrogen under tomato
following tillage, cover cropping, and nitrogen fertilization. Journal of Environmental
Quality 28(6): 1837-1844.
Saleh, A., E. Osei, D.B. Jaynes, B. Du, and J.G. Arnold. 2005. Economic and environmental
impacts of LSNT and cover crops for nitrate-nitrogen reduction in Walnut Creek
watershed, Iowa, using fern and enhanced SWAT models. Annual Meeting of the
American-Society-of-Agricultural-and-Biological-Engineers, Madison, Wl, American
Society of Agricultural & Biological Engineers.
SAN. 2007. Managing cover crops profitably. 3rd ed. Handbook Series Book 9, A. Clark, ed.,
Sustainable Agriculture Network, Beltsville, MD.
. Accessed April 20, 2010.
Sanders, J.H., D. Valentine, E. Schaeffer, D. Greene, and J. McCoy. 1991. Double Pipe Creek
RCWP: Ten Year Report. U.S. Department of Agriculture, University of Maryland
Cooperative Extension Service, Maryland Department of the Environment, and Carroll
County Soil Conservation District.
2-172 Chapter 2. Agriculture
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
Sands, G.R., I. Song, L.M. Busman, and B.J. Hansen. 2008. The Effects of Subsurface
Drainage Depth and Intensity on Nitrate Loads in the Northern Cornbelt. Transactions of
the ASABE 51(3): 937-946.
Schaafsma, J.A., A.M. Baldwin, and C.A. Streb. 2000. An evaluation of a constructed wetland to
treat wastewater from a dairy farm in Maryland, USA. Ecological Engineering
14(1-2):199-206.
Sharma, N.C., and S.V. Sahi. 2005. Characterization of phosphate accumulation in Lolium
multiflorum for remediation of phosphorus-enriched soils. Environmental Science &
Technology 39(14):5475-5480.
Sharpley, A.N. 1995. Dependence of runoff phosphorus on extractable soil phosphorus. Journal
of Environmental Quality 24, 920-926.
Shaviv, A. 2005. Controlled release fertilizers. Paper presented at IFA International Workshop
on Enhanced-Efficiency Fertilizers, June 28-30, 2005, Frankfurt, Germany.
Shi, Y., D.B. Parker, N.A. Cole, B.W. Auvermann, and J.E. Mehlhorn. 2001. Surface
amendments to minimize ammonia emissions from beef cattle feedlots. Transactions of
the ASAE 44(3):677-682.
Shigaki, F., P.J.A. Kleinman, J.P. Schmidt, A.N. Sharpley, and A.L. Allen. 2008. Impact of
Dredging on Phosphorus Transport in Agricultural Drainage Ditches of the Atlantic Coastal
Plain. Journal of the American Water Resources Association 44(6): 1500-1511.
Shoji, S., J. Delgado, A. Mosier, and Y. Miura. 1999. Use of controlled release fertilizers and
nitrification inhibitors to increase nitrogen use efficiency and to conserve air and water
quality. Annual Conference of the Soil-and-Water-Conservation-Society. Marcel Dekker
Inc, Biloxi, Mississippi, pp. 1051-1070.
Singer, J.W., C.A. Cambardella, and T.B. Moorman. 2008. Enhancing Nutrient Cycling by
Coupling Cover Crops with Manure Injection. Agronomy Journal 100(6): 1735-1739.
Singh, A., K.D. Casey, W.D. King, A.J. Pescatore, R.S. Gates, and M.J. Ford. 2009. Efficacy of
urease inhibitor to reduce ammonia emission from poultry houses. Journal of Applied
Poultry Research 18(1):34-42.
Sistani, K.R., G.E. Brink, and J.L. Oldham. 2008. Managing broiler litter application rate and
grazing to decrease watershed runoff losses. Journal of Environmental Quality
37(2):718-724.
Sistani, K.R., H.A. Torbert, T.R. Way, C.H. Bolster, D.H. Pote, and J.G. Warren. 2009. Broiler
Litter Application Method and Runoff Timing Effects on Nutrient and Escherichia coli
Losses from Tall Fescue Pasture. Journal of Environmental Quality 38(3):1216-1223.
Chapter 2. Agriculture 2-173
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
Skaggs, R.W., and M.A. Youssef. 2008. Effect of Drainage Water Management on Water
Conservation and Nitrogen Losses to Surface Waters. Paper presented at 16th National
Nonpoint Source Monitoring Workshop, September 14-18, 2008, Columbus, OH.
Skaggs, R.W., M.A. Youssef, G.M. Chescheir, and J.W. Gilliam. 2005. Effect of Drainage
Intensity on Nitrogen Losses from Drained Lands. Transactions oftheASAE
48(6):2169-2177.
Smeltz, H.L., R.O. Evans, D.L. Osmond, and G.D. Jennings. 2005. Nitrate Reduction Through
Controlled Drainage & Nutrient Management Plans. ASAE Meeting Paper No. 052236,
St. Joseph, Ml 2005 ASAE Annual International Meeting, Tampa: 12.
Smith, D.R., E.A. Warnemuende, C. Huang, and G.C. Heathman. 2007. How does the first year
tilling a long-term no-tillage field impact soluble nutrient losses in runoff? So/7 & Tillage
Research 95(1-2):11-18.
Smith, D.R., P.A. Moore, C.L Griffis, T.C. Daniel, D.R. Edwards, and D.L. Boothe. 2001. Effects
of alum and aluminum chloride on phosphorus runoff from swine manure. Journal of
Environmental Quality 30(3):992-998.
Smith, D.R., Moore, P.A., Miles, D.M., Haggard, B.E., Daniel, T.C. 2004. Decreasing
phosphorus runoff losses from land-applied poultry litter with dietary modifications and
alum addition. Journal of Environmental Quality 33:2210-2216.
Smith, E., R. Gordon, A. Madani, and G. Stratton. 2006. Year-round treatment of dairy
wastewater by constructed wetlands in Atlantic Canada. Wetlands 26(2):349-357.
Smolen, M.D., and F.J. Humenik. 1989. National Water Quality Evaluation Project 1988 Annual
Report: Status of Agricultural Nonpoint Source Projects. EPA-506/9-89/002. U.S.
Environmental Protection Agency, and U.S. Department of Agriculture, Washington, DC.
Snyder, C.S. 2008. Fertilizer nitrogen BMPs to limit losses that contribute to global warming.
Fertilizer Best Management Practices series funded by U.S. Department of Agriculture
Natural Resources Conservation Service Conservation Innovation Grant. International
Plant Nutrition Institute. June 2008 Ref. # 08057 Item 30-3210.
Sojka, R. 2009. Matrix-based fertilizer: A new fertilizer formulation concept to reduce nutrient
leaching. In Proceedings of the New Zealand Lime and Fertilizer Institute Workshop.
Sommer, S.G., M. Maahn, M., Poulsen, M. Hjorth, and J. Sehested. 2008. Interactions between
phosphorus feeding strategies for pigs and dairy cows and separation efficiency of slurry.
Environmental Technology 29:75-80.
2-174 Chapter 2. Agriculture
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
Sotomayor-Ramirez, D., G.A. Martinez, J. Ramirez-Avila, and E. Mas. 2008. Effectiveness of
grass filter strips for runoff nutrient and sediment reduction in dairy sludge-amended
pastures. Journal of Agriculture of the University of Puerto Rico 92(1-2): 1-14.
Staats, K.E., Y. Arai, and D.L. Sparks. 2004. Alum amendment effects on phosphorus release
and distribution in poultry litter-amended sandy soils. Journal of Environmental Quality
33:1904-1911.
Staver, K.W. and R.B. Brinsfield. 1998. Using cereal grain winter cover crops to reduce
groundwater nitrate contamination in the mid-Atlantic coastal plain. Journal of Soil and
Water Conservation 53(3): 230-240.
Stivers L.J., D.C. Brainard, G.S. Abawi, and D.W. Wolfe. 1998. Cover crops for vegetable
production in the Northeast. Information Bulletin 244. Cornell Cooperative Extension.
. Accessed
April 20, 2010.
Stout, W.L., A.M. Sharpley, W.J. Gburek, and H.B. Pionke. 1999. Reducing phosphorus export
from croplands with FBC fly ash and FGD gypsum. Fuel 78(2): 175-178.
Stout, W.L, S.L Fales, LD. Muller, R.R. Schnabel, G.F. Elwinger, and S.R. Weaver. 2000.
Assessing the effect of management intensive grazing on water quality in the northeast
U.S. Journal of Soil and Water Conservation 55(2):238-243.
Strock, J.S., P.M. Porter, and M.P. Russelle. 2004. Cover cropping to reduce nitrate loss
through subsurface drainage in the northern U.S. corn belt. Journal of Environmental
Qtya/rty33(3):1010-1016.
Sullivan, P. 2003. Overview of cover crops and green manures. Appropriate Technology
Transfer for Rural Areas. < http://www.attra.ncat.org/attra-pub/PDF/covercrop.pdf>.
Accessed April 20, 2010.Sullivan, T.J. A. Moore, D.R. Thomas, E. Mallery, K.U. Snyder,
M. Wustenberg, J. Wustenberg, S.D. Mackey, and D.L. Moore. 2007. Efficacy of
vegetated buffers in preventing transport of fecal coliform bacteria from Pasturelands.
Environmental Management 40(6):958-965.
Swink, S.N., Q.M. Ketterings, L.E. Chase, K.J. Czymmek, and J.C. Mekken. 2009. Past and
future phosphorus balances for agricultural cropland in New York State. Journal of Soil
and Water Conservation 64(2): 120-133.
Szogi, A.A., and M.B. Vanotti. 2007. Abatement of ammonia emissions from swine lagoons
using polymer-enhanced solid-liquid separation. Applied Engineering in Agriculture
23(6): 837-845.
Chapter 2. Agriculture 2-175
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
Tan, C.S., C.F. Drury, T.Q. Zhang, W.D. Reynolds, and J.D. Gaynor. 2003. Wetland -Reservoir
System Improves Water Quality and Crop Production. ASAE Meeting Paper No. 032327,
St. Joseph, Ml 2003 ASAE Annual International Meeting, Las Vegas: 9.
Tan, C.S., T.Q. Zhang, W.D. Reynolds, C.F. Drury, and A. Liptay. 2003. Farm-Scale Processing
Tomato Production using Surface and Subsurface Drip Irrigation and Fertigation. Paper
number 032092, 2003 ASAE Annual Meeting. American Society of Agricultural and
Biological Engineers, St. Joseph, Ml.
Tan, C.S., C.F. Drury, J.D. Gaynor, W.D. Reynolds, T.W. Welacky, and T.Q. Zhang. 2004.
Effect of Water Table Management on Water Quality and Crop Yield at the Plot and Farm
Scale Fields. ASAE-CIGR Meeting Paper No. 042241, St. Joseph, Ml 2004 ASAE Annual
International Meeting, Ottawa: 10.
Tanner, C.C., M.L. Nguyen, and J.P.S. Sukias. 2005. Nutrient removal by a constructed wetland
treating subsurface drainage from grazed dairy pasture. Agriculture Ecosystems &
Environment 105( 1 -2): 145-162.
Tate, K.W., G.A. Nader, D.J. Lewis, E.R. Atwill, and J.M. Connor. 2000. Evaluation of buffers to
improve the quality of runoff from irrigated pastures. Journal of Soil and Water
Conservation 55(4):473-478.
Trask, J.R., P.K. Kalita, M.S. Kuhlenschmidt, R.D. Smith, and T.L. Funk. 2004. Overland and
Near-Surface Transport of Cryptosporidium parvum from Vegetated and Nonvegetated
Surfaces. Journal of Environmental Quality 33:984-993.
Trias, M., Z. Hu, M.M. Mortula, R.J. Gordon, and G.A. Gagnon. 2004. Impact of seasonal
variation on treatment of swine wastewater. Environmental Technology 25(7):775-781.
Turtola, E., L. Alakukku, R. Uusitalo, and A. Kaseva. 2007. Surface runoff, subsurface drainflow
and soil erosion as affected by tillage in a clayey Finnish soil. Agricultural and Food
Science 16(4): 332-351.
Ullman, J.L., S. Mukhtar, R.E. Lacey, and J.B. Carey. 2004. A review of literature concerning
odors, ammonia, and dust from broiler production facilities: 4. Remedial management
practices. Journal of Applied Poultry Research 13(3):521-531.
USDA-ARS (U.S. Department of Agriculture-Agricultural Research Service). 2005. Revised
Universal Soil Loss Equation 2 - Overview of RUSLE2, US DA-Agricultural Research
Service, . Accessed February
21,2010.
2-176 Chapter 2. Agriculture
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
USDA-NRCS (U.S. Department of Agriculture-Natural Resources Conservation Service). 1977.
National Handbook of Conservation Practices. Natural Resources Conservation Service
(formerly Soil Conservation Service), U.S. Department of Agriculture, Washington, DC.
. Accessed April 30, 2010.
USDA-NRCS (U.S. Department of Agriculture-Natural Resources Conservation Service). 2002.
Part 637 environmental engineering national engineering handbook, chapter 3 constructed
wetlands.
. Accessed 12/17/2009.
USDA-NRCS (U.S. Department of Agriculture-Natural Resources Conservation Service). 2008.
Surface Drainage, Field Ditch 607-1. Electronic Field Office Technical Guide-Maryland.
USDA-NRCS (U.S. Department of Agriculture-Natural Resources Conservation Service). 2010.
Average cost estimates for conservation practices for FY10: average cost/unit and
estimated total costs.
.
Accessed 4/21/2010.
USDA-NRCS (U.S. Department of Agriculture-Natural Resoures Conservation Service). 2010a.
Determining highly erodible fields, M_180_511_B_11 - Fourth Edition Amendment 1,
September 2006 < http://policy.nrcs.usda.gov/viewerFS.aspx?hid=20177>. Accessed April
30,2010.
USDA-NRCS (U.S. Department of Agriculture-Natural Resources Conservation Service). 2010b.
NSSH Part 622, Ecological and interpretative groups.
. Accessed April 30,
2010.
USDA-NRCS (U.S. Department of Agriculture-Natural Resoures Conservation Service). 2010c.
HEL soil erodibility index, M_180_511_A_01 - Fourth Edition Amendment 1, September
2006 < http://policv.nrcs.usda.gov/viewerFS.aspx?hid=20172>. Accessed April 30, 2010.
USDA-NRCS (U.S. Department of Agriculture-Natural Resources Conservation Service).
201 Od. Save energy, save money, conservation practices that save: crop residue
management, . Accessed
February 21, 2010.
USEPA (U.S. Environmental Protection Agency). 2003. National Management Measures for the
Control of Nonpoint Pollution from Agriculture. EPA-841-B-03-004, U.S. Environmental
Protection Agency, Office of Water, Washington, DC. .
Accessed February 21, 2010.
Chapter 2. Agriculture 2-177
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
USEPA (U.S. Environmental Protection Agency). 2005. National management measures to
protect and restore wetlands and riparian areas for the abatement of nonpoint source
pollution,EPA-841-B-05-003, U.S. Environmental Protection Agency, Office of Water,
Washington, DC, . Accessed
February 21, 2010.
U.S. Inflation Calculator. 2010. U.S. Inflation Calculator, .
Accessed April 21, 2010.
Uusi-Kamppa, J. 2006. Vegetated buffer zones for agricultural non-point source pollution
control. So/7 Management for Sustainability 38:337-343.
Uusitalo, R., E. Turtola, and R. Lemola. 2007. Phosphorus losses from a subdrained clayey soil
as affected by cultivation practices. Agricultural and Food Science 16(4):352-365.
van der Meer, H.G. 2008. Optimising manure management for GHG outcomes. Australian
Journal of Experimental Agriculture 48(1-2):38-45.
van Driel, P.W., W.D. Robertson, and L.C. Merkley. 2006. Denitrification of agricultural drainage
using wood-based reactors. American Society of Agricultural and Biological Engineers
49(2):9.
van Vliet, L.J.P., B.J. Zebarth, and G. Derksen. 2002. Effect of fall-applied manure practices on
runoff, sediment, and nutrient surface transport from silage corn in south coastal British
Columbia. Canadian Journal of Soil Science 82(4):445-456.
van Vliet, L.J.P., S. Bittman, G. Derksen, and C.G. Kowalenko. 2006. Aerating grassland before
manure application reduces runoff nutrient loads in a high rainfall environment. Journal of
Environmental Quality 35:903-911.
Vanotti, M.B., and A.A. Szogi. 2008. Water quality improvements of wastewater from confined
animal feeding operations after advanced treatment. Journal of Environmental Quality
37(5):S86-S96.
Vanotti, M.B., A.A. Szogi, P.O. Millner, and J.H. Loughrin. 2009. Development of a second-
generation environmentally superior technology for treatment of swine manure in the USA.
Bioresource Technology 100(22):5406-5416.
Vanotti, M.B., D.M.C. Rashash, and P.G. Hunt. 2002. Solid-liquid separation of flushed swine
manure with PAM: Effect of wastewater strength. Transactions of theASAE 45(6): 1959-
1969.
Vanotti, M.B., J.M. Rice, A.Q. Ellison, P.G. Hunt, F.J. Humenik, and C.L. Baird. 2005. Solid-
liquid separation of swine manure with polymer treatment and sand filtration. Transactions
of the ASAE 48(4): 1567-1574.
2-178 Chapter 2. Agriculture
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
Vitti, G.C., J.E. Tavares, P.H.C. Luz, J.L. Favarin, and M.C.G. Costa. 2002. Influence of
ammonium sulfate in mixture with urea on the volatilization of NH3-N. Revista Brasileira
de Ciencia do Solo 26:663-671.
Warren, J.G., K.R. Sistani, T.R. Way, D.A. Mays, and D.H Pote. 2008. A New Method of Poultry
Litter Application to Perennial Pasture: Subsurface Banding. So/7 Science Society of
America Journal 72:1831-1837.
Weber, D., A. Drizo, E. Twhohig, S. Bird, and D. Ross. 2007. Upgrading constructed wetlands
phosphorus reduction from a dairy effluent using electric arc furnace steel slag filters.
Water Science and Technology 56(3): 135-143.
Weil, R., C. White, and Y. Lawley. 2009. Forage radish: A new multi-purpose cover crop for the
Mid-Atlantic. Fact Sheet 824. University of Maryland Cooperative Extension.
. Accessed April 20, 2010.
White, J.R., K.R. Reddy, and J. Majer-Newman. 2006. Hydrologic and vegetation effects on
water column phosphorus in wetland mesocosms. So/7 Science Society of America
Journal 70(4): 1242-1251.
Wood, J.D., R. Gordon, A. Madani, and G.W. Stratton. 2008. A long term assessment of
phosphorus treatment by a constructed wetland receiving dairy wastewater. Wetlands
28(3):715-723.
Woodbury, B.L., J.A. Nienaber, and R.A. Eigenberg. 2000. Evaluation of a passive feedlot runoff
control treatment system. Animal, Agricultural and Food Processing Wastes: 266-272.
Woodbury, B.L., J.A. Nienaber, and R.A. Eigenberg. 2002. Operational evaluation of a passive
beef cattle feedlot runoff control and treatment system. Applied Engineering in Agriculture
18(5): 541-545.
Woodbury, B.L., J.A. Nienaber, and R.A. Eigenberg. 2003. Performance of a passive feedlot
runoff control and treatment system. Transactions of the ASAE 46(6): 1525-1530.
Wossink, A. 2001. Cost and Benefits of Best Management Practices to Control Nitrogen in the
Piedmont. . Accessed December 1,
2009.
Wossink, A., and D. Osmond. 2001. Cost and Benefits of Best Management Practices to
Control Nitrogen in the Lower Coastal Plain. 8/01—2M—JL/VG AG-620, E01-38976
. Accessed December 1, 2009.
Yang, P.Y., H.J. Chen, and S.J. Kim. 2003. Integrating entrapped mixed microbial cell (EMMC)
process for biological removal of carbon and nitrogen from dilute swine wastewater.
Bioresource Technology 86(3):245-252.
Chapter 2. Agriculture 2-179
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
Yongabi, K.A., P.L. Harris, and D.M. Lewis. 2009. Poultry faeces management with a simple low
cost plastic digester. African Journal of Biotechnology 8(8): 1560-1566.
Yuan, Y., S.M. Dabney, and R.L. Bingner. 2002. Cost effectiveness of agricultural BMPs for
sediment reduction in the Mississippi Delta. Journal of Soil and Water Conservation
57(5):259-267.
Zeneca Ag Products. 1994. Conservation farming—A practical handbook for cotton growers.
Zeneca, Inc., 42 pp.
Zhou, X., M.J. Helmers, M. AI-Kaisi, and H.M. Hanna. 2009. Cost-effectiveness and cost-benefit
analysis of conservation management practices for sediment reduction in an Iowa
agricultural watershed. Journal of Soil and Water Conservation 64(5):314-323.
Zvomuya, F., C.J. Rosen, and S.C. Gupta. 2006. Phosphorus sequestration by chemical
amendments to reduce leaching from wastewater applications. Journal of Environmental
Quality 35:207-215.
2-180 Chapter 2. Agriculture
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
Appendix 1: USDA National Conservation Practice
Standards (Practice Codes)
Chapter 2. Agriculture 2-181
-------
313- 1
NATURAL RESOURCES CONSERVATION SERVICE
CONSERVATION PRACTICE STANDARD
WASTE STORAGE FACILITY
(No.)
CODE 313
DEFINITION
A waste storage impoundment made by
constructing an embankment and/or
excavating a pit or dugout, or by fabricating a
structure.
PURPOSE
To temporarily store wastes such as manure,
wastewater, and contaminated runoff as a
storage function component of an agricultural
waste management system.
CONDITIONS WHERE PRACTICE APPLIES
• Where the storage facility is a component of
a planned agricultural waste management
system
• Where temporary storage is needed for
organic wastes generated by agricultural
production or processing
• Where the storage facility can be
constructed, operated and maintained
without polluting air or water resources
• Where site conditions are suitable for
construction of the facility
• To facilities utilizing embankments with an
effective height of 35 feet or less where
damage resulting from failure would be
limited to damage of farm buildings,
agricultural land, or township and country
roads.
• To fabricated structures including tanks,
stacking facilities, and pond appurtenances.
CRITERIA
General Criteria Applicable to All Waste
Storage Facilities.
Laws and Regulations. Waste storage
facilities must be planned, designed, and
constructed to meet all federal, state, and local
laws and regulations.
Location. To minimize the potential for
contamination of streams, waste storage
facilities should be located outside of
floodplains. However, if site restrictions
require location within a floodplain, they shall
be protected from inundation or damage from
a 25-year flood event, or larger if required by
laws, rules, and regulations. Waste storage
facilities shall be located so the potential
impacts from breach of embankment,
accidental release, and liner failure are
minimized; and separation distances are such
that prevailing winds and landscape elements
such as building arrangement, landforms, and
vegetation minimize odors and protect
aesthetic values.
Storage Period. The storage period is the
maximum length of time anticipated between
emptying events. The minimum storage period
shall be based on the timing required for
environmentally safe waste utilization
considering the climate, crops, soil, equipment,
and local, state, and federal regulations.
Design Storage Volume. The design storage
volume equal to the required storage volume,
shall consist of the total of the following as
appropriate:
(a) Manure, wastewater, and other wastes
accumulated during the storage period
(b) Normal precipitation less evaporation on
Conservation practice standards are reviewed periodically, and updated if needed. To obtain
the current version of this standard, contact the Natural Resources Conservation Service
NRCS, NHCP
October 2003
2-182
-------
313-2
the surface area (at the design storage
volume level) of the facility during the
storage period
(c) Normal runoff from the facility's drainage
area during the storage period
(d) 25-year, 24-hour precipitation on the
surface (at the required design storage
volume level) of the facility
(e) 25-year, 24-hour runoff from the facility's
drainage area
(f) Residual solids after liquids have been
removed. A minimum of 6 inches shall be
provided for tanks
(g) Additional storage as may be required to
meet management goals or regulatory
requirements
Inlet. Inlets shall be of any permanent type
designed to resist corrosion, plugging, freeze
damage and ultraviolet ray deterioration while
incorporating erosion protection as necessary.
Emptying Component. Some type of
component shall be provided for emptying
storage facilities. It may be a facility such as a
gate, pipe, dock, wet well, pumping platform,
retaining wall, or ramp. Features to protect
against erosion, tampering, and accidental
release shall be incorporated as necessary.
Accumulated Solids Removal. Provision
shall be made for periodic removal of
accumulated solids to preserve storage
capacity. The anticipated method fordoing
this must be considered in planning,
particularly in determining the configuration of
ponds and type of seal, if any.
Safety. Design shall include appropriate
safety features to minimize the hazards of the
facility. Ramps used to empty liquids shall
have a slope of 4 horizontal to 1 vertical or
flatter. Those used to empty slurry, semi-solid,
or solid waste shall have a slope of 10
horizontal to 1 vertical or flatter unless special
traction surfaces are provided. Warning signs,
fences, ladders, ropes, bars, rails, and other
devices shall be provided, as appropriate, to
ensure the safety of humans and livestock.
Ventilation and warning signs must be
provided for covered waste holding structures,
as necessary, to prevent explosion, poisoning,
or asphyxiation. Pipelines shall be provided
NRCS, NHCP
October 2003
with a water-sealed trap and vent, or similar
device, if there is a potential, based on design
configuration, for gases to enter buildings or
other confined spaces. Ponds and uncovered
fabricated structures for liquid or slurry waste
with walls less than 5 feet above ground
surface shall be fenced and warning signs
posted to prevent children and others from
using them for other than their intended
purpose.
Erosion Protection. Embankments and
disturbed areas surrounding the facility shall
be treated to control erosion.
Liners. Liners shall meet or exceed the
criteria in Pond Sealing or Lining (521).
Additional Criteria for Waste Storage Ponds
Soil and foundation. The pond shall be
located in soils with an acceptable permeability
that meets all applicable regulation, or the
pond shall be lined. Information and guidance
on controlling seepage from waste
impoundments can be found in the Agricultural
Waste Management Field Handbook
(AWMFH), Appendix 10D.
The pond shall have a bottom elevation that is
a minimum of 2 feet above the seasonal high
water table unless features of special design
are incorporated that address buoyant forces,
pond seepage rate and non-encroachment of
the water table by contaminants. The water
table may be lowered by use of perimeter
drains, if feasible, to meet this requirement.
Maximum Operating Level. The maximum
operating level for waste storage ponds shall
be the pond level that provides for the required
volume less the volume contribution of
precipitation and runoff from the 25-year, 24-
hour storm event plus the volume allowance
for residual solids after liquids have been
removed. A permanent marker or recorder
shall be installed at this maximum operating
level to indicate when drawdown should begin.
The marker or recorder shall be referenced
and explained in the O&M plan.
Outlet. No outlet shall automatically release
storage from the required design volume.
Manually operated outlets shall be of
permanent type designed to resist corrosion
and plugging.
2-183
-------
313-3
Embankments. The minimum elevation of the
top of the settled embankment shall be 1 foot
above the waste storage pond's required
volume. This height shall be increased by the
amount needed to ensure that the top
elevation will be maintained after settlement.
This increase shall be not less than 5 percent.
The minimum top widths are shown in Table 1.
The combined side slopes of the settled
embankment shall not be less than 5
horizontal to 1 vertical, and neither slope shall
be steeper than 2 horizontal to 1 vertical
unless provisions are made to provide stability.
Table 1 - Minimum Top Widths
Total embankment
Height, ft.
15 or less
15-20
20-25
25-30
30-35
Top Width,
ft.
8
10
12
14
15
between the floor slab and the bedrock or an
alternative that will achieve equal protection.
Table 2 - Presumptive Allowable Bearing
Stress Values
Foundation Description
Crystalline Bedrock
Sedimentary Rock
Sandy Gravel or Gravel
Sand, Silty Sand, Clayey
Sand, Silty Gravel, Clayey
Gravel
Clay, Sandy Clay, Silty Clay,
Clayey Silt
Allowable
Stress
12000psf
6000 psf
5000 psf
3000 psf
2000 psf
1 Basic Building Code, 12th Edition, 1993,
Building Officials and Code Administrators,
Inc. (BOCA)
Excavations. Unless supported by a soil
investigation, excavated side slopes shall be
no steeper than 2 horizontal to 1 vertical.
Additional Criteria for Fabricated
Structures
Foundation. The foundations of fabricated
waste storage structures shall be proportioned
to safely support all superimposed loads
without excessive movement or settlement.
Where a non-uniform foundation cannot be
avoided or applied loads may create highly
variable foundation loads, settlement should
be calculated from site-specific soil test data.
Index tests of site soil may allow correlation
with similar soils for which test data is
available. If no test data is available,
presumptive bearing strength values for
assessing actual bearing pressures may be
obtained from Table 2 or another nationally
recognized building code. In using
presumptive bearing values, adequate
detailing and articulation shall be provided to
avoid distressing movements in the structure.
Foundations consisting of bedrock with joints,
fractures, or solution channels shall be treated
or a separation distance provided consisting of
a minimum of 1 foot of impermeable soil
Liquid Tightness. Applications such as
tanks, that require liquid tightness shall be
designed and constructed in accordance with
standard engineering and industry practice
appropriate for the construction materials used
to achieve this objective.
Structural Loadings. Waste storage
structures shall be designed to withstand all
anticipated loads including internal and
external loads, hydrostatic uplift pressure,
concentrated surface and impact loads, water
pressure due to seasonal high water table,
and frost or ice pressure and load
combinations in compliance with this
standard and applicable local building
codes.
The lateral earth pressures should be
calculated from soil strength values
determined from the results of appropriate soil
tests. Lateral earth pressures can be
calculated using the procedures in TR-74. If
soil strength tests are not available, the
presumptive lateral earth pressure values
indicated in Table 3 shall be used.
2-184
NRCS, NHCP
October 2003
-------
313-4
TABLE 3 - LATERAL EARTH PRESSURE VALUES1
Soil
Description4
Clean gravel, sand or
sand-gravel mixtures
(maximum 5% fines)5
Gravel, sand, silt and
clay mixtures (less than
50% fines)
Coarse sands with silt
and and/or clay (less
than 50% fines)
Low-plasticity silts and
clays with some sand
and/or gravel (50% or
more fines)
Fine sands with silt
and/or clay (less than
50% fines)
Low to medium plasticity
silts and clays with little
sand and/or gravel (50%
or more fines)
High plasticity silts and
clays (liquid limit more
than 50)6
Unified
Classification4
GP, GW, SP, SW
All gravel sand dual
symbol classifications
and GM, GC, SC, SM,
SC-SM
CL, ML, CL-ML
SC, SM, SC-SM
CL, ML, CL-ML
CH, MH
Equivalent fluid pressure (Ib/ft2/ft of depth)
Above seasonal high
water table2
Free-
standing
walls
30
35
45
65
-
Frame
tanks
50
60
75
85
-
Below seasonal high water table3
Free-
standing
walls
80
80
90
95
-
Frame
tanks
90
100
105
110
-
1 For lightly-compacted soils (85% to 90% maximum standard density.) Includes compaction by use of typical
farm equipment.
2 Also below seasonal high water table if adequate drainage is provided.
3 Includes hydrostatic pressure.
4 All definitions and procedures in accordance with ASTM D 2488 and D 653.
5 Generally, only washed materials are in this category
6 Not recommended. Requires special design if used.
Lateral earth pressures based upon equivalent
fluid assumptions shall be assigned according
to the following conditions:
• Rigid frame or restrained wall. Use the
values shown in Table 3 under the column
"Frame tanks," which gives pressures
comparable to the at-rest condition.
• Flexible or yielding wall. Use the values
shown in Table 3 under the column "Free-
standing walls," which gives pressures
comparable to the active condition. Walls
in this category are designed on the basis of
gravity for stability or are designed as a
cantilever having a base wall thickness to
height of backfill ratio not more than 0.085.
Internal lateral pressure used for design shall
be 65 Ib/ft2 where the stored waste is not
protected from precipitation. A value of 60
NRCS, NHCP
October 2003
2-185
-------
313-5
Ib/ft may be used where the stored waste is
protected from precipitation and will not
become saturated. Lesser values may be
used if supported by measurement of actual
pressures of the waste to be stored. If heavy
equipment will be operated near the wall, an
additional two feet of soil surcharge shall be
considered in the wall analysis.
Tank covers shall be designed to withstand
both dead and live loads. The live load values
for covers contained in ASAE EP378.3, Floor
and Suspended Loads on Agricultural
Structures Due to Use, and in ASAE EP 393.2,
Manure Storages, shall be the minimum used.
The actual axle load for tank wagons having
more than a 2,000 gallon capacity shall be
used.
If the facility is to have a roof, snow and wind
loads shall be as specified in ASAE EP288.5,
Agricultural Building Snow and Wind Loads. If
the facility is to serve as part of a foundation or
support for a building, the total load shall be
considered in the structural design.
Structural Design. The structural design shall
consider all items that will influence the
performance of the structure, including loading
assumptions, material properties and
construction quality. Design assumptions and
construction requirements shall be indicated
on standard plans.
Tanks may be designed with or without covers.
Covers, beams, or braces that are integral to
structural performance must be indicated on
the construction drawings. The openings in
covered tanks shall be designed to
accommodate equipment for loading, agitating,
and emptying. These openings shall be
equipped with grills or secure covers for safety,
and for odor and vector control.
All structures shall be underlain by free
draining material or shall have a footing
located below the anticipated frost depth.
Fabricated structures shall be designed
according to the criteria in the following
references as appropriate:
• Steel: "Manual of Steel Construction",
American Institute of Steel Construction.
• Timber: "National Design Specifications
for Wood Construction", American Forest
and Paper Association.
• Concrete: "Building Code Requirements
for Reinforced Concrete, ACI 318",
American Concrete Institute.
• Masonry: "Building Code Requirements
for Masonry Structures, ACI 530",
American Concrete Institute.
Slabs on Grade. Slab design shall consider
the required performance and the critical
applied loads along with both the subgrade
material and material resistance of the
concrete slab. Where applied point loads are
minimal and liquid-tightness is not required,
such as barnyard and feedlot slabs subject
only to precipitation, and the subgrade is
uniform and dense, the minimum slab
thickness shall be 4 inches with a maximum
joint spacing of 10 feet. Joint spacing can be
increased if steel reinforcing is added based
on subgrade drag theory.
For applications where liquid-tightness is
required such as floor slabs of storage tanks,
the minimum thickness for uniform foundations
shall be 5 inches and shall contain distributed
reinforcing steel. The required area of such
reinforcing steel shall be based on subgrade
drag theory as discussed in industry guidelines
such as American Concrete Institute, ACI 360,
"Design of Slabs-on-Grade".
When heavy equipment loads are to be
resisted and/or where a non-uniform
foundation cannot be avoided, an appropriate
design procedure incorporating a subgrade
resistance parameter(s) such as ACI 360 shall
be used.
CONSIDERATIONS
Waste storage facilities should be located as
close to the source of waste and polluted
runoff as practicable.
Non-polluted runoff should be excluded from
the structure to the fullest extent possible
except where its storage is advantageous to
the operation of the agricultural waste
management system.
Freeboard for waste storage tanks should be
considered.
Solid/liquid separation of runoff or wastewater
entering pond facilities should be considered to
minimize the frequency of accumulated solids
NRCS, NHCP
October 2003
2-186
-------
313-6
removal and to facilitate pumping and
application of the stored waste.
Due consideration should be given to
environmental concerns, economics, the
overall waste management system plan, and
safety and health factors.
Considerations for Minimizing the Potential
for and Impacts of Sudden Breach of
Embankment or Accidental Release from
the Required Volume.
Features, safeguards, and/or management
measures to minimize the risk of failure or
accidental release, or to minimize or mitigate
impact of this type of failure should be
considered when any of the categories listed in
Table 4 might be significantly affected.
The following should be considered either
singly or in combination to minimize the
potential of or the consequences of sudden
breach of embankments when one or more of
the potential impact categories listed in Table 4
may be significantly affected:
1. An auxiliary (emergency) spillway
2. Additional freeboard
3. Storage for wet year rather than normal
year precipitation
4. Reinforced embankment - such as,
additional top width, flattened and/or
armored downstream side slopes
5. Secondary containment
Table 4 - Potential Impact Categories from
Breach of Embankment or Accidental
Release
1. Surface water bodies - perennial streams,
lakes, wetlands, and estuaries
2. Critical habitat for threatened and
endangered species.
3. Riparian areas
4. Farmstead, or other areas of habitation
5. Off-farm property
6. Historical and/or archaeological sites or
structures that meet the eligibility criteria
for listing in the National Register of
Historical Places.
The following options should be considered to
minimize the potential for accidental release
from the required volume through gravity
outlets when one or more of the potential
impact categories listed in Table 4 may be
significantly affected:
1. Outlet gate locks or locked gate housing
2. Secondary containment
3. Alarm system
4. Another means of emptying the required
volume
Considerations for Minimizing the Potential
of Waste Storage Pond Liner Failure.
Sites with categories listed in Table 5 should
be avoided unless no reasonable alternative
exists. Under those circumstances,
consideration should be given to providing an
additional measure of safety from pond
seepage when any of the potential impact
categories listed in Table 5 may be
significantly affected.
Table 5 - Potential Impact Categories for
Liner Failure
1. Any underlying aquifer is at a shallow
depth and not confined
2. The vadose zone is rock
3. The aquifer is a domestic water supply
or ecologically vital water supply
4. The site is located in an area of
solutionized bedrock such as
limestone or gypsum.
Should any of the potential impact categories
listed in Table 5 be affected, consideration
should be given to the following:
1. A clay liner designed in accordance with
procedures of AWMFH Appendix 10D with
a thickness and coefficient of permeability
so that specific discharge is less than 1 x
10 ~6 cm/sec
2. A flexible membrane liner over a clay liner
NRCS, NHCP
October 2003
2-187
-------
313-7
3. A geosynthetic clay liner (GCL) flexible
membrane liner
4. A concrete liner designed in accordance
with slabs on grade criteria for fabricated
structures requiring water tightness
Considerations for Improving Air Quality
To reduce emissions of greenhouse gases,
ammonia, volatile organic compounds, and
odor, other practices such as Anaerobic
Digester - Ambient Temperature (365),
Anaerobic Digester- Controlled Temperature
(366), Waste Facility Cover (367), and
Composting Facility (317) can be added to the
waste management system.
Adjusting pH below 7 may reduce ammonia
emissions from the waste storage facility but
may increase odor when waste is surface
applied (see Waste Utilization, 633).
Some fabric and organic covers have been
shown to be effective in reducing odors.
PLANS AND SPECIFICATIONS
Plans and specifications shall be prepared in
accordance with the criteria of this standard
and shall describe the requirements for
applying the practice to achieve its intended
use.
OPERATION AND MAINTENANCE
An operation and maintenance plan shall be
developed that is consistent with the purposes
of the practice, its intended life, safety
requirements, and the criteria for its design.
The plan shall contain the operational
requirements for emptying the storage facility.
This shall include the requirement that waste
shall be removed from storage and utilized at
locations, times, rates, and volume in
accordance with the overall waste
management system plan.
In addition, for ponds, the plan shall include an
explanation of the permanent marker or
recorder installed to indicate the maximum
operating level.
The plan shall include a strategy for removal
and disposition of waste with the least
environmental damage during the normal
storage period to the extent necessary to
insure the pond's safe operation. This strategy
is for the removal of the contribution of unusual
storm events that may cause the pond to fill to
capacity prematurely with subsequent design
inflow and usual precipitation prior to the end
of the normal storage period.
Development of an emergency action plan
should be considered for waste storage
facilities where there is a potential for
significant impact from breach or accidental
release. The plan shall include site-specific
provisions for emergency actions that will
minimize these impacts.
2-188
NRCS, NHCP
October 2003
-------
340- 1
NATURAL RESOURCES CONSERVATION SERVICE
CONSERVATION PRACTICE STANDARD
COVER CROP
(Ac.)
CODE 340
DEFINITION
Crops including grasses, legumes and forbs
for seasonal cover and other conservation
purposes.
PURPOSE
• Reduce erosion from wind and water.
• Increase soil organic matter content.
• Capture and recycle or redistribute
nutrients in the soil profile.
• Promote biological nitrogen fixation.
• Increase biodiversity.
• Weed suppression.
• Provide supplemental forage.
• Soil moisture management.
• Reduce particulate emissions into the
atmosphere.
• Minimize and reduce soil compaction.
CONDITIONS WHERE PRACTICE APPLIES
On all lands requiring vegetative cover for
natural resource protection and or
improvement.
CRITERIA
General Criteria Applicable to All Purposes
Plant species, seedbed preparation, seeding
rates, seeding dates, seeding depths, fertility
requirements, and planting methods will be
consistent with approved local criteria and site
conditions.
The species selected will be compatible with
other components of the cropping system.
Cover crops will be terminated by harvest,
frost, mowing, tillage, crimping, and/or
herbicides in preparation for the following crop.
Herbicides used with cover crops will be
compatible with the following crop.
Avoid using plants that are on the state's
noxious weed or invasive species lists.
Cover crop residue will not be burned.
Additional Criteria to Reduce Erosion from
Wind and Water
Cover crop establishment, in conjunction with
other practices, will be timed so that the soil
will be adequately protected during the critical
erosion period(s).
Plants selected for cover crops will have the
physical characteristics necessary to provide
adequate protection.
The amount of surface and/or canopy cover
needed from the cover crop shall be
determined using current erosion prediction
technology.
Additional Criteria to Increase Soil Organic
Matter Content
Cover crop species will be selected on the
basis of producing high volumes of organic
material and or root mass to maintain or
improve soil organic matter.
The NRCS Soil Conditioning Index (SCI)
procedure will be used to determine the
amount of biomass required to have a positive
trend in the soil organic matter subfactor.
Conservation practice standards are reviewed periodically and updated if needed. To obtain
the current version of this standard, contact your Natural Resources Conservation Service
State Office or visit the electronic Field Office Technical Guide.
NRCS, NHCP
May 2006
2-189
-------
340-2
The cover crop will be terminated as late as
feasible to maximize plant biomass production,
considering the time needed to prepare the
field for planting the next crop and soil
moisture depletion.
Additional Criteria to Capture and Recycle
Excess Nutrients in the Soil Profile
Cover crops will be established and actively
growing before the expected period(s) of
nutrient leaching.
Cover crop species will be selected for their
ability to take up large amounts of nutrients
from the rooting profile of the soil.
When used to redistribute nutrients from
deeper in the profile up to the surface layer,
the cover crop will be killed in relation to the
planting date of the following crop. If the
objective is to best synchronize the use of
cover crop as a green manure to cycle
nutrients, factors such as the carbon/nitrogen
ratios may be considered to kill early and have
a faster mineralization of nutrients to match
release of nutrient with uptake by following
cash crop. A late kill may be used if the
objectives are to use as a biocontrol and
maximize the addition of organic matter. The
right moment to kill the cover crop will depend
on the specific rotation, weather and
objectives.
Additional Criteria to Promote Biological
Nitrogen Fixation
Only legumes or legume-grass mixtures will be
established as cover crops.
The specific Rhizobium bacteria for the
selected legume will either be present in the
soil or the seed will be inoculated at the time of
planting.
Additional Criteria to Increase Biodiversity
Cover crop species shall be selected that have
different maturity dates, attract beneficial
insects, increase soil biological diversity, serve
as a trap crop for damaging insects, and/or
provide food and cover for wildlife habitat
management.
Additional Criteria for Weed Suppression
Species for the cover crop will be selected for
their chemical or physical characteristics to
suppress or compete with weeds.
Cover crops residues will be left on the soil
surface to maximize allelopathic (chemical)
and mulching (physical) effects.
For long-term weed suppression, reseeding
annuals and/or biennial species can be used.
Additional Criteria to Provide Supplemental
Forage
Species selected will have desired forage
traits, be palatable to livestock, and not
interfere with the production of the subsequent
crop.
Forage provided by the cover crop may be
hayed or grazed as long as sufficient biomass
is left for resource protection.
Additional Criteria for Soil Moisture
Management
Terminate growth of the cover crop sufficiently
early to conserve soil moisture for the
subsequent crop. Cover crops established for
moisture conservation shall be left on the soil
surface.
In areas of potential excess soil moisture,
allow the cover crop to grow as long as
possible to maximize soil moisture removal.
Additional Criteria to Reduce Particulate
Emissions into the Atmosphere
Manage cover crops and their residues so that
at least 80% ground cover is maintained during
planting operations for the following crop.
Additional Criteria to Minimize and Reduce
Soil Compaction
Select and manage cover crop species that will
produce deep roots and large amounts of
surface or root biomass to increase soil
organic matter, improve soil structure and
increase soil moisture through better
infiltration.
CONSIDERATIONS
Plant cover crop in a timely matter to establish
a good stand.
NRCS NHCP
May 2006
2-190
-------
340-3
Maintain an actively growing cover crop as late
as feasible to maximize plant growth, allowing
time to prepare the field for the next crop and
moisture depletion.
Use deep-rooted species to maximize nutrient
recovery.
Use grasses to utilize more soil nitrogen, and
legumes utilize both nitrogen and phosphorus.
Avoid cover crop species that harbor or
carryover potentially damaging diseases or
insects.
For most purposes for which cover crops are
established, the combined canopy and surface
cover is at nearly 90 percent or greater, and
the above ground (dry weight) biomass
production is at least 4,000 Ibs/acre.
Cover crops may be used to improve site
conditions for establishment of perennial
species.
Use plant species that enhance bio-fuels
opportunities.
Use plant species that enhance forage
opportunities for pollinators.
PLANS AND SPECIFICATIONS
Plans and specifications will be prepared for
the practice site. Plans for the establishment
of cover crops shall include:
• Species or species of plants to be
established.
• Seeding rates.
• Recommended seeding dates.
• Establishment procedure.
• Planned rates and timing of nutrient
application.
• Planned dates for destroying cover crop.
• Other information pertinent to establishing
and managing the cover crop.
Plans and specifications for the establishment
and management of cover crops may be
recorded in narrative form, on job sheets, or on
other forms.
OPERATION AND MAINTENANCE
Control growth of the cover crop to reduce
competition from volunteer plants and shading.
Control weeds in cover crops by mowing or by
using other pest management techniques.
Control soil moisture depletion by selecting
water efficient plant species and terminating
the cover crop before excessive transpiration.
REFERENCES
Bowman, G., C. Cramer, and C. Shirley. A.
Clark (ed.). 1998. Managing cover crops
profitably. 2nd ed. Sustainable Agriculture
Network Handbook Series; bk 3. National
Agriculture Library. Beltsville, MD.
Hargrove, W.L., ed. Cover crops for clean
water. SWCS, 1991.
Magdoff, F. and H. van Es. Cover Crops. 2000.
p. 87-96 In Building soils for better crops. 2nd
ed. Sustainable Agriculture Network
Handbook Series; bk4. National Agriculture
Library. Beltsville, MD.
Reeves, D.W. 1994. Cover crops and erosion.
p. 125-172 In J.L. Hatfield and B.A. Stewart
(eds.) Crops Residue Management. CRC
Press, Boca Raton, FL.
NRCS, NHCP
May 2006
2-191
-------
359- 1
NATURAL RESOURCES CONSERVATION SERVICE
CONSERVATION PRACTICE STANDARD
WASTE TREATMENT LAGOON
(No.)
CODE 359
DEFINITION
A waste treatment impoundment made by
constructing an embankment and/or
excavating a pit or dugout.
PURPOSE
To biologically treat waste, such as manure
and wastewater, and thereby reduce pollution
potential by serving as a treatment
component of a waste management system.
CONDITIONS WHERE PRACTICE APPLIES
• Where the lagoon is a component of a
planned agricultural waste management
system.
• Where treatment is needed for organic
wastes generated by agricultural
production or processing.
• On any site where the lagoon can be
constructed, operated and maintained
without polluting air or water resources.
• To lagoons utilizing embankments with
an effective height of 35 feet or less
where damage resulting from failure
would be limited to damage of farm
buildings, agricultural land, or township
and country roads.
CRITERIA
General Criteria for All Lagoons
Laws and Regulations. All Federal, state,
and local laws, rules, and regulations
governing the construction and use of waste
treatment lagoons must be followed.
Location. To minimize the potential for
contamination of streams, lagoons should be
located outside of floodplains. However, if
site restrictions require location within a
floodplain, they shall be protected from
inundation or damage from a 25-year flood
event, or larger if required by laws, rules, and
regulations. Lagoons shall be located so the
potential impacts from breach of
embankment, accidental release, and liner
failure are minimized; and separation
distances are such that prevailing winds and
landscape elements such as building
arrangement, landforms, and vegetation
minimize odors and protect aesthetic values.
Lagoons should be located so they have as
little drainage area as possible. If a lagoon
has a drainage area, the volume of normal
runoff during the treatment period and 25-
year, 24-hour storm event runoff shall be
included in the required volume of the lagoon.
Soils and Foundation. The lagoon shall be
located in soils with an acceptable
permeability that meets all applicable
regulations, or the lagoon shall be lined.
Information and guidance on controlling
seepage from waste impoundments can be
found in the Agricultural Waste Management
Field Handbook (AWMFH), Appendix 10D.
The lagoon shall have a bottom elevation that
is a minimum of 2 feet above the seasonal
high water table unless special design
features are incorporated that address
buoyant forces, lagoon seepage rates, and
non-encroachment of the water table by
contaminants. The water table may be
lowered by use of perimeter drains to meet
this requirement.
Conservation practice standards are reviewed periodically, and updated if needed. To obtain
the current version of this standard, contact the Natural Resources Conservation Service.
NRCS, NHCP
October 2003
2-192
-------
359-2
Flexible Membranes. Flexible membrane
liners shall meet or exceed the requirements
of flexible membrane linings specified in
Pond Sealing or Lining, Flexible Membrane
(code 521A).
Required Volume. The lagoon shall have
the capability of storing the following
volumes:
• Volume of accumulated sludge for the
period between sludge removal events;
• Minimum treatment volume (anaerobic
lagoons only);
• Volume of manure, wastewater, and
other wastes accumulated during the
treatment period;
• Depth of normal precipitation less
evaporation on the surface area (at the
required volume level) of the lagoon
during the treatment period;
• Depth of the 25-year, 24-hour storm
precipitation on the surface area (at the
required volume level) of the lagoon.
Treatment Period. The treatment period is
the detention time between drawdown
events. It shall be the greater of either 60
days; or the time required to provide the
storage that allows environmentally safe
utilization of waste considering the climate,
crops, soil, and equipment requirements; or
as required by local, state, and Federal
regulations.
Waste Loading. Daily waste loading shall
be based on the maximum daily loading
considering all waste sources that will be
treated by the lagoon. Reliable local
information or laboratory test data should be
used if available. If local information is not
available Chapter 4 of the AWMFH may be
used for estimating waste loading.
Embankments. The minimum elevation of
the top of the settled embankment shall be 1
foot above the lagoon's required volume.
This height shall be increased by the amount
needed to ensure that the top elevation will
be maintained after settlement. This increase
shall be not less than 5 percent. The
minimum top widths are shown in Table 1.
The combined side slopes of the settled
embankment shall not be less than 5
NRCS, NHCP
October 2003
horizontal to 1 vertical, and neither slope
shall be steeper than 2 horizontal to 1 vertical
unless provisions are made to provide
stability.
Table 1 - Minimum Top Widths
Total embankment
Height, ft.
15 or less
15-20
20-25
25-30
30-35
Top Width,
ft.
8
10
12
14
15
Excavations. Unless supported by a soil
investigation, excavated side slopes shall be
no steeper than 2 horizontal to 1 vertical.
Inlet. Inlets shall be of any permanent type
designed to resist corrosion, plugging, freeze
damage, and ultraviolet ray deterioration,
while incorporating erosion protection as
necessary. Inlets shall be provided with a
water-sealed trap and vent, or similar device
if there is a potential, based on design
configuration, for gases to enter buildings or
other confined spaces.
Outlet. Outlets from the required volume
shall be designed to resist corrosion and
plugging. No outlet shall automatically
discharge from the required volume of the
lagoon.
Facility for Drawdown. Measures that
facilitate safe drawdown of the liquid level in
the lagoon shall be provided. Access areas
and ramps used to withdraw waste shall have
slopes that facilitate a safe operating
environment. Docks, wells, pumping
platforms, retaining walls, etc. shall permit
drawdown without causing erosion or
damage to liners.
Sludge Removal. Provision shall be made
for periodic removal of accumulated sludge to
preserve the treatment capacity of the
lagoon.
Erosion Protection. Embankments and
disturbed areas surrounding the lagoon shall
be treated to control erosion. This includes
the inside slopes of the lagoon as needed to
protect the integrity of the liner.
Safety. Design shall include appropriate
safety features to minimize the hazards of the
2-193
-------
359-3
lagoon. The lagoon shall be fenced around
the perimeter and warning signs posted to
prevent children and others from using it for
other than its intended purpose.
Additional Criteria for Anaerobic Lagoons
Loading Rate. Anaerobic lagoons shall be
designed to have a minimum treatment
volume based on Volatile Solids (VS) loading
per unit of volume. The maximum loading
rate shall be as indicated in AWMFH Figure
10-22 or according to state regulatory
requirements, whichever is more stringent.
Operating Levels. The maximum operating
level shall be the lagoon level that provides
the required volume less the 25-year, 24-hour
storm event precipitation on the surface of
the lagoon. The maximum drawdown level
shall be the lagoon level that provides volume
for the required minimum treatment volume
plus the volume of accumulated sludge
between sludge removal events. Permanent
markers shall be installed at these elevations.
The proper operating range of the lagoon is
above the maximum drawdown level and
below the maximum operating level. These
markers shall be referenced and described in
the O&M plan.
Depth Requirements. The minimum depth
at maximum drawdown shall be 6 feet. If
subsurface conditions prevent practicable
construction to accommodate the minimum
depth at maximum drawdown, a lesser depth
may be used, if the volume requirements are
met.
Additional Criteria for Naturally Aerobic
Lagoons
Loading Rate. Naturally aerobic lagoons
shall be designed to have a minimum
treatment surface area as determined on the
basis of daily BOD5 loading per unit of lagoon
surface. The required minimum treatment
surface area shall be the surface area at
maximum drawdown. The maximum loading
rate shall be as indicated by AWMFH Figure
10-25 or according to state regulatory
requirements, whichever is more stringent.
Operating Levels. The maximum operating
level shall be the lagoon level that provides
the required volume less the 25-year, 24-hour
storm event on the lagoon surface. The
maximum drawdown level shall be the lagoon
level that provides volume for the volume of
manure, wastewater, and clean water
accumulated during the treatment period plus
the volume of accumulated sludge between
sludge removal events. Permanent markers
shall be installed at these elevations. The
proper operating range of the lagoon is above
the maximum drawdown level and below the
maximum operating level. These markers
shall be referenced and described in the
O&M plan.
Depth Requirements. The minimum depth
at maximum drawdown shall be 2 feet. The
maximum liquid level shall be 5 feet.
Additional Criteria for Mechanically
Aerated Lagoons
Loading Rate. Mechanically aerated waste
treatment lagoons' treatment function shall be
designed on the basis of daily BOD5 loading
and aeration equipment manufacturer's
performance data for oxygen transfer and
mixing. Aeration equipment shall provide a
minimum of 1 pound of oxygen for each
pound of daily BOD5 loading.
Operating Levels. The maximum operating
level shall be the lagoon level that provides
the required lagoon volume less the 25-year,
24-hour storm event precipitation and shall
not exceed the site and aeration equipment
limitations. A permanent marker or recorder
shall be installed at this elevation. The
proper operating range of the lagoon is below
this elevation and above the minimum
treatment elevation established by the
manufacturer of the aeration equipment. This
marker shall be referenced and described in
the O&M plan.
CONSIDERATIONS
General
Lagoons should be located as close to the
source of waste as possible.
Solid/liquid separation treatment should be
considered between the waste source and
the lagoon to reduce loading.
The configuration of the lagoon should be
based on the method of sludge removal and
method of sealing.
NRCS, NHCP
October 2003
2-194
-------
359-4
Due consideration should be given to
economics, the overall waste management
system plan, and safety and health factors.
Considerations for Minimizing the
Potential for and Impacts of Sudden
Breach of Embankment or Accidental
Release from the Required Volume
Features, safeguards, and/or management
measures to minimize the risk of
embankment failure or accidental release, or
to minimize or mitigate impact of this type of
failure should be considered when any of the
categories listed in Table 2 might be
significantly affected.
The following should be considered either
singly or in combination to minimize the
potential of or the consequences of sudden
breach of embankments when one or more of
the potential impact categories listed in Table
2 may be significantly affected:
• An auxiliary (emergency) spillway
• Additional freeboard
• Storage volume for the wet year rather
than normal year precipitation
• Reinforced embankment - such as,
additional top width, flattened and/or
armored downstream side slopes
• Secondary containment
• Water level indicators or recorders
Table 2- Potential Impact Categories
from Breach of Embankment or
Accidental Release
1. Surface water bodies - perennial
streams, lakes, wetlands, and estuaries
2. Critical habitat for threatened and
endangered species
3. Riparian areas
4. Farmstead, or other areas of habitation
5. Off-farm property
6. Historical and/or archaeological sites or
structures that meet the eligibility
criteria for listing in the National
Register of Historical Places
The following should be considered to
minimize the potential for accidental release
from the required volume through gravity
outlets when one or more of the potential
NRCS, NHCP
October 2003
impact categories listed in Table 2 may be
significantly affected:
• Outlet gate locks or locked gate housing
• Secondary containment
• Alarm system
• Another means of emptying the required
volume
Considerations for Minimizing the
Potential of Lagoon Liner Seepage
Consideration should be given to providing
an additional measure of safety from lagoon
seepage when any of the potential impact
categories listed in Table 3 may be affected.
Table 3 - Potential Impact Categories for
Liner Seepage
1. Any underlying aquifer is at a shallow depth
and not confined
2. The vadose zone is rock
3. The aquifer is a domestic water supply or
ecologically vital water supply
4. The site is located in an area of carbonate
rock (limestone or dolomite)
Should any of the potential impact categories
listed in Table 3 be affected, consideration
should be given to the following:
• A clay liner designed in accordance with
procedures of AWMFH, Appendix 10D
with a thickness and coefficient of
permeability so that specific discharge is
less than 1 x 10~6 cm/sec.
• A flexible membrane liner
• A geosynthetic clay liner (GCL) flexible
membrane liner
• A concrete liner designed in accordance
with slabs on grade criteria, Waste
Storage Facility (313), for fabricated
structures requiring water tightness.
Considerations for Improving Air Quality
To reduce emissions of greenhouse gases,
ammonia, volatile organic compounds, and
odor:
• Reduce the recommended loading rate
for anaerobic lagoons to one-half the
values given in AWMFH Figure 10-22.
2-195
-------
359-5
• Use additional practices such as
Anaerobic Digester - Ambient
Temperature (365), Anaerobic Digester-
Controlled Temperature (366), Waste
Facility Cover (367) and Composting
Facilities (code 317) in the waste
management system.
• Liquid/solid separation prior to discharge
to lagoon will reduce volatile solids (VS)
loading resulting in reduced gaseous
emissions and odors. Composting of
solids will further reduce emissions.
• Design lagoons to be naturally aerobic or
to allow mechanical aeration.
Adjusting pH below 7 may reduce ammonia
emissions from the lagoon but may increase
odor when waste is surface applied (See
Waste Utilization, code 633).
PLANS AND SPECIFICATIONS
Plans and specifications shall be prepared in
accordance with the criteria of this standard
and shall describe the requirements for
applying the practice to achieve its intended
use.
OPERATION AND MAINTENANCE
An operation and maintenance plan shall be
developed that is consistent with the
purposes of the practice, its intended life,
safety requirements, and the criteria for
design. The plan shall contain the
operational requirements for drawdown and
the role of permanent markers. This shall
include the requirement that waste be
removed from the lagoon and utilized at
locations, times, rates, and volume in
accordance with the overall waste
management system plan. In addition, the
plan shall include a strategy for removal and
disposition of waste with least environmental
damage during the normal treatment period
to the extent necessary to insure the lagoon's
safe operation. This strategy shall also
include the removal of unusual storm events.
Development of an emergency action plan
should be considered for lagoons where
there is a potential for significant impact from
breach or accidental release. The plan shall
include site-specific provisions for emergency
actions that will minimize these impacts.
2-196
NRCS, NHCP
October 2003
-------
362- 1
NATURAL RESOURCES CONSERVATION SERVICE
CONSERVATION PRACTICE STANDARD
DIVERSION
(Ft.)
CODE 362
DEFINITION
A channel constructed across the slope
generally with a supporting ridge on the
lower side.
PURPOSE
This practice may be applied as part of a
resource management system to support
one or more of the following purposes.
• Break up concentrations of water on
long slopes, on undulating land
surfaces, and on land that is generally
considered too flat or irregular for
terracing.
• Divert water away from farmsteads,
agricultural waste systems, and other
improvements.
• Collect or direct water for water-
spreading or water-harvesting systems.
• Increase or decrease the drainage area
above ponds.
• Protect terrace systems by diverting
water from the top terrace where
topography, land use, or land
ownership prevents terracing the land
above.
• Intercept surface and shallow
subsurface flow.
• Reduce runoff damages from upland
runoff.
• Reduce erosion and runoff on urban or
developing areas and at construction or
mining sites.
• Divert water away from active gullies
or critically eroding areas.
• Supplement water management on
conservation cropping or stripcropping
systems.
CONDITIONS WHERE PRACTICE
APPLIES
This applies to all cropland and other land
uses where surface runoff water control
and or management is needed. It also
applies where soils and topography are
such that the diversion can be constructed
and a suitable outlet is available or can be
provided.
CRITERIA
Capacity. Diversions as temporary
measures, with an expected life span of
less than 2 years, shall have a minimum
capacity for the peak discharge from the 2-
year frequency, 24-hour duration storm.
Diversions that protect agricultural land
shall have a minimum capacity for the
peak discharge from a 10-year frequency,
24 -hour duration storm.
Diversions designed to protect areas such
as urban areas, buildings, roads, and
animal waste management systems shall
Conservation practice standards are reviewed periodically, and updated if needed. To obtain the current
version of this standard, contact the Natural Resources Conservation Service.
NRCS, NHCP
September 2001
2-197
-------
362-2
have a minimum capacity for the peak
discharge from a storm frequency
consistent with the hazard involved but not
less than a 25-year frequency, 24-hour
duration storm. Freeboard shall be not less
than 0.3 ft.
Design depth is the channel storm flow
depth plus freeboard, where required.
Cross section. The channel may be
parabolic, V-shaped, or trapezoidal. The
diversion shall be designed to have stable
side slopes.
The ridge shall have a minimum top width
of 4 feet at the design depth. The ridge
height shall include an adequate settlement
factor.
The ridge top width may be 3 feet at the
design depth for diversions with less than
10 acres drainage area above cropland,
pastureland, or woodland.
The top of the constructed ridge at any
point shall not be lower than the design
depth plus the specified overfill for
settlement.
The design depth at culvert crossings shall
be the culvert headwater depth for the
design storm plus freeboard.
Grade and velocity. Channel grades may
be uniform or variable. Channel velocity
shall not exceed that considered non-
erosive for the soil and planned vegetation
or lining.
Maximum channel velocities for
permanently vegetated channels shall not
exceed those recommended in the NRCS
Engineering Field Handbook (EFH) Part
650, Chapter 7, or Agricultural Research
Service (ARS) Agricultural Handbook 667,
Stability Design of Grass-Lined Open
Channels (Sept. 1987).
When the capacity is determined by the
formula Q = A V and the V is calculated by
NRCS, NHCP
September 2001
2-198
using Manning's equation, the highest
expected value of "n" shall be used.
Location. The outlet conditions,
topography, land use, cultural operations,
cultural resources, and soil type shall
determine the location of the diversion.
Protection against sedimentation.
Diversions normally should not be used
below high sediment producing areas.
When they are, a practice or combination
of practices needed to prevent damaging
accumulations of sediment in the channel
shall be installed. This may include
practices such as land treatment erosion
control practices, cultural or tillage
practices, vegetated filter strip, or
structural measures. Install practices in
conjunction with or before the diversion
construction.
If movement of sediment into the channel
is a problem, the design shall include extra
capacity for sediment or periodic removal
as outlined in the operation and
maintenance plan.
Outlets. Each diversion must have a safe
and stable outlet with adequate capacity.
The outlet may be a grassed waterway, a
lined waterway, a vegetated or paved area,
a grade stabilization structure, an
underground outlet, a stable watercourse, a
sediment basin, or a combination of these
practices. The outlet must convey runoff
to a point where outflow will not cause
damage. Vegetative outlets shall be
installed and established before diversion
construction to insure establishment of
vegetative cover in the outlet channel.
The release rate of an under ground outlet,
when combined with storage, shall be such
that the design storm runoff will not
overtop the diversion ridge.
The design depth of the water surface in
the diversion shall not be lower than the
design elevation of the water surface in the
-------
362-3
outlet at their junction when both are
operating at design flow.
Vegetation. Disturbed areas that are not to
be cultivated shall be seeded as soon as
practicable after construction.
Lining. If the soils or climatic conditions
preclude the use of vegetation for erosion
protection, non-vegetative linings such as
gravel, rock riprap, cellular block, or other
approved manufactured lining systems may
be used.
CONSIDERATIONS
A diversion in a cultivated field should be
aligned and spaced from other structures or
practices to permit use of modern farming
equipment. The side slope lengths should
sized to fit equipment widths when
cropped.
At non-cropland sites, consider planting
native vegetation in areas disturbed due to
construction.
Maximize wetland functions and values
with the diversion design. Minimize
adverse effects to existing functions and
values. Diversion of upland water to
prevent entry into a wetland may convert a
wetland by changing the hydrology. Any
construction activities should minimize
disturbance to wildlife habitat.
Opportunities should be explored to restore
and improve wildlife habitat, including
habitat for threatened, endangered, and
other species of concern.
On landforms where archeological sites are
likely to occur, use techniques to maximize
identification of such sites prior to
planning, design, and construction.
PLANS AND SPECIFICATIONS
Plans and specification for installing
diversions shall be in keeping with this
standard and shall describe the
requirements for applying the practice to
achieve its intended purpose.
OPERATION AND MAINTENANCE
An operation and maintenance plan shall
be prepared for use by the client. The plan
shall include specific instructions for
maintaining diversion capacity, storage,
ridge height, and outlets.
The minimum requirements to be
addressed in the operation and
maintenance plan are:
1. Provide periodic inspections,
especially immediately following
significant storms.
2. Promptly repair or replace damaged
components of the diversion as
necessary.
3. Maintain diversion capacity, ridge
height, and outlet elevations especially
if high sediment yielding areas are in
the drainage area above the diversion.
Establish necessary clean-out
requirements.
4. Each inlet for underground outlets
must be kept clean and sediment
buildup redistributed so that the inlet is
at the lowest point. Inlets damaged by
farm machinery must be replaced or
repaired immediately.
5. Redistribute sediment as necessary to
maintain the capacity of the diversion.
6. Vegetation shall be maintained and
trees and brush controlled by hand,
chemical and/or mechanical means.
7. Keep machinery away from steep
sloped ridges. Keep equipment
operators informed of all potential
hazards.
NRCS, NHCP
September 2001
2-199
-------
382- 1
NATURAL RESOURCES CONSERVATION SERVICE
CONSERVATION PRACTICE STANDARD
FENCE
(Ft.)
CODE 382
DEFINITION
A constructed barrier to animals or people.
PURPOSE
This practice facilitates the accomplishment of
conservation objectives by providing a means to
control movement of animals and people,
including vehicles.
CONDITIONS WHERE PRACTICE APPLIES
This practice may be applied on any area where
management of animal or human movement is
needed.
CRITERIA
General Criteria Applicable to All Purposes
Fencing materials, type and design offence
installed shall be of a high quality and durability.
The type and design offence installed will meet
the management objectives and site challenges.
Based on need, fences may be permanent,
portable, or temporary.
Fences shall be positioned to facilitate
management requirements. Ingress/egress
features such as gates and cattle guards shall
be planned. The fence design and installation
should have the life expectancy appropriate for
management objectives and shall follow all
federal, state and local laws and regulations.
Height, size, spacing and type of materials used
will provide the desired control, life expectancy,
and management of animals and people of
concern.
CONSIDERATIONS
The fence design and location should consider:
topography, soil properties, livestock
management and safety, livestock trailing,
wildlife class and movement, location and
adequacy of water facilities, development of
potential grazing systems, human access and
safety, landscape aesthetics, erosion problems,
moisture conditions, flooding potential, stream
crossings, and durability of materials. When
appropriate, natural barriers should be utilized
instead of fencing.
Where applicable, cleared rights-of-way may be
established which would facilitate fence
construction and maintenance. Avoid clearing of
vegetation during the nesting season for
migratory birds.
Fences across gullies, canyons or streams may
require special bracing, designs or approaches.
Fence design and location should consider ease
of access for construction, repair and
maintenance.
Fence construction requiring the removal of
existing unusable fence should provide for the
proper disposal of scrap materials to prevent
harm to animals, people and equipment.
PLANS AND SPECIFICATIONS
Plans and specifications are to be prepared for
all fence types, installations and specific sites.
Requirements for applying the practice to
achieve all of its intended purposes shall be
described.
Conservation practice standards are reviewed periodically and updated if needed. To obtain
the current version of this standard, contact your Natural Resources Conservation Service
State Office or visit the electronic Field Office Technical Guide.
2-200
NRCS, NHCP
February 2008
-------
382-2
OPERATION AND MAINTENANCE
Regular inspection offences should be part of
an ongoing maintenance program. Inspection of
fences after storms and other disturbance
events is necessary to insure the continued
proper function of the fence. Maintenance and
repairs will be performed in a timely manner as
needed, including tree/limb removal and water
gap replacement.
Remove and properly discard all broken fencing
material and hardware. All necessary
precautions should be taken to ensure the safety
of construction and maintenance crews.
REFERENCES
Bell, H.M. 1973. Rangeland management for
livestock production. University of Oklahoma
Press.
Heady, H.F. and R.D. Child. 1994. Rangeland
ecology and management. Western Press.
Holechek, J.L., R.D. Pieper, and C.H. Herbel.
2001. Range management: principles and
practices. Prentice Hall.
Stoddard, L.A., A.D. Smith, and T.W. Box.
1975. Range management. McGraw-Hill Book
Company.
United States Department of Interior, Bureau of
Land Management and United States
Department of Agriculture, Forest Service.
1988. Fences. Missoula Technology and
Development Center.
United States Department of Agriculture, Natural
Resources Conservation Service. 2005.
Electric fencing for serious graziers. Columbia,
Mo.
United States Department of Agriculture, Natural
Resources Conservation Service. 2003.
National range and pasture handbook, revision
1. Washington, DC.
Vallentine, J.F. 1971. Range development and
improvement. Brigham Young University Press.
NRCS, NHCP
February 2008
2-201
-------
472- 1
NATURAL RESOURCES CONSERVATION SERVICE
CONSERVATION PRACTICE STANDARD
ACCESS CONTROL
(Ac.)
CODE 472
DEFINITION
The temporary or permanent exclusion of
animals, people, vehicles, and/or equipment
from an area.
PURPOSE
Achieve and maintain desired resource
conditions by monitoring and managing the
intensity of use by animals, people, vehicles,
and/or equipment in coordination with the
application schedule of practices, measures and
activities specified in the conservation plan.
CONDITIONS WHERE PRACTICE APPLIES
This practice applies on all land uses.
CRITERIA
Use-regulating activities (e.g., posting of signs,
patrolling, gates, fences and other barriers,
permits) shall achieve the intended purpose and
include mitigating associated resource concerns
to acceptable levels during their installation,
operation, and maintenance. Activities will
complement the application schedule and life
span of other practices specified in the
conservation plan.
Each activity or measure will identify the entity to
be monitored and regulated (animals, people,
vehicles and/or equipment) and specify the
intent, intensity, amounts, and timing of
exclusion by that entity. Activities may involve
temporary to permanent exclusion of one to all
entities.
Placement, location, dimensions and materials
(e.g., signs, gates), and frequency of use (e.g.,
continuous, specific season, or specific dates)
shall be described for each activity including
monitoring frequency.
CONSIDERATIONS
Even though usage of the area is monitored and
controlled, the land manager and/or tenant
should be advised about emergency
preparedness agencies and related information,
e.g., the local fire/wildfire control agency and
pumper truck water sources on or near the area.
Information should be designated initially and re-
designated annually.
PLANS AND SPECIFICATIONS
Specifications for applying this practice shall be
prepared for each area and recorded using
approved specification sheets, job sheets, and
narrative statements in the conservation plan, or
other acceptable documentation.
OPERATION AND MAINTENANCE
Monitoring of the effectiveness of use-regulating
activities will be performed routinely and at least
annually with changes made to specifications
and operation and maintenance requirements as
necessary.
Modifications to activities and use of measures
are allowed temporarily to accommodate
emergency-level contingencies such as wildfire,
hurricane, drought, or flood as long as resource
conditions are maintained.
Conservation practice standards are reviewed periodically, and updated if needed. To obtain
the current version of this standard, contact your Natural Resources Conservation Service
State Office, or visit the Field Office Technical Guide.
2-202
NRCS, NHCP
May 2008
-------
472-2
REFERENCES U.S. Department of Transportation, Federal
0 . .. u .. . r- • •-, •-, -7- ivji LJ Highway Administration. 2003. Manual on
Gucmski, H.; M.J. Furniss, R.R. Ziemer, M.H. ,, ., ' ,,. „ , , ^ . , 0, , .
D i onrn <= t ,j *u • < Uniform Traffic Control Devices for Streets and
Brookes. 2001. Forest roads: a synthesis of .... ...... T „. ^ ,. ^ . ,
scientific information. Gen. Tech. Rep. "IQ^S ~ Pf 5H Tr^ic ^on ral Dne(!'ces for
PNWGTR-509. Portland, OR: U.S. Department ^ow-V olume fRoads Washing ton DC
of Agriculture, Forest Service, Pacific Northwest http: /mutcd.fhwa.dot.qov/pdfs/2003r1 r2/pdf md
Research Station.
NRCS, NHCP
May 2008
2-203
-------
554- 1
NATURAL RESOURCES CONSERVATION SERVICE
CONSERVATION PRACTICE STANDARD
DRAINAGE WATER MANAGEMENT
(Ac.)
CODE 554
DEFINITION
The process of managing water discharges
from surface and/or subsurface agricultural
drainage systems.
PURPOSE
The purpose of this practice is:
• Reduce nutrient, pathogen, and/or
pesticide loading from drainage systems
into downstream receiving waters
• Improve productivity, health, and vigor of
plants
• Reduce oxidation of organic matter in soils
• Reduce wind erosion or particulate matter
(dust) emissions
• Provide seasonal wildlife habitat
CONDITIONS WHERE PRACTICE APPLIES
This practice is applicable to agricultural lands
with surface or subsurface agricultural
drainage systems that are adapted to allow
management of drainage discharges.
The practice may not apply where saline or
sodic soil conditions require special
considerations.
This practice does not apply to the
management of irrigation water supplied
through a subsurface drainage system. For
that purpose, use NRCS Conservation
Practice Standard, Irrigation Water
Management (449).
CRITERIA
General Criteria Applicable to All Purposes
The management of gravity drained outlets
shall be accomplished by adjusting the
elevation of the drainage outlet.
The management of pumped drainage outlets
shall be accomplished by raising the on-off
elevations for pump cycling.
Structures and pumps shall be located where
they are convenient to operate and maintain.
Raising the outlet elevation of the flowing drain
shall result in an elevated free water surface
within the soil profile.
When operated in free drainage mode, water
control structures shall not restrict the flow of
the drainage system.
Drainage discharges and water levels shall be
managed in a manner that does not cause
adverse impacts to other properties or
drainage systems.
Release of water from control structures shall
not allow flow velocities in surface drainage
system components to exceed acceptable
velocities prescribed by NRCS Conservation
Practice Standard, Surface Drainage, Main or
Lateral (608).
Release of water from flow control structures
shall not allow flow velocities in subsurface
drains to exceed velocities prescribed by
NRCS Conservation Practice Standard,
Subsurface Drain (606).
2-201
Conservation practice standards are reviewed periodically, and updated if needed. To obtain
the current version of this standard, contact your Natural Resources Conservation Service
State Office, or visit the Field Office Technical Guide.
NRCS, NHCP
September 2008
-------
554-2
Additional Criteria to Reduce Nutrient.
Pathogen, and/or Pesticide Loading
During non-cropped periods, the system shall
be in managed drainage mode within 30 days
after the season's final field operation, until at
least 30 days before commencement of the
next season's field operations, except during
system maintenance periods or to provide
trafficability when field operations are
necessary.
The drain outlet shall be raised prior to and
during liquid manure applications to prevent
direct leakage of manure into drainage pipes
through soil macro pores (cracks, worm holes,
root channels).
Manure applications shall be in accordance
with NRCS Conservation Practice Standards,
Nutrient Management (590) and Waste
Utilization (633).
Additional Criteria to Improve Productivity.
Health, and Vigor of Plants
When managing drainage outflow to maintain
water in the soil profile for use by crops or
other vegetation, the elevation at which the
outlet is set shall be based on root depth and
soil type.
If using this practice to control rodents, apply in
conjunction with NRCS Conservation Practice
Standard, Pest Management (595).
Additional Criteria to Reduce Oxidation of
Organic Matter in Soils
Drainage beyond that necessary to provide an
adequate root zone for the crop shall be
minimized.
To reduce oxidation of organic matter, the
outlet elevation shall be set to enable the water
table to rise to the ground surface, or to a
designated maximum elevation, for sufficient
time to create anaerobic soil conditions. The
implementation of this practice must result in a
reduced average annual thickness of the
aerated layer of the soil.
Additional Criteria to Reduce Wind Erosion
or Participate Matter (Dust) Emissions
When the water table is at the design
elevation, the system shall provide a moist
field soil surface, either by ponding or through
capillary action from the elevated water table.
Additional Criteria to Provide Seasonal
Wildlife Habitat
During the non-cropped season, the elevation
of the drainage outlet shall be managed in a
manner consistent with a habitat evaluation
procedure that addresses targeted species.
CONSIDERATIONS
In-field water table elevation monitoring
devices can be used to improve water table
management.
Reducing mineralization of organic soils may
decrease the release of soluble phosphorus,
but water table management may increase the
release of soluble phosphorus from mineral
soils.
Elevated water tables may increase the runoff
portion of outflow from fields. Consider
conservation measures that control sediment
loss and associated nutrient discharge to
waterways.
Elevate the drainage outlet for subsurface
drains during and after manure applications to
decrease potential for nutrient and pathogen
loading to receiving waters.
Consider manure application setbacks from
streams, flowing drain lines, and sinkholes, to
reduce risk of contamination.
To maintain proper root zone development and
aeration, downward adjustments of the
drainage outlet control elevation may be
necessary, especially following significant
rainfall events.
Monitoring of root zone development may be
necessary if the free water surface in the soil
profile is raised during the growing season.
PLANS AND SPECIFICATIONS
Plans and specifications shall be prepared in
accordance with the criteria of this standard as
necessary and shall describe the requirements
for applying the practice to achieve its intended
purpose (s).
NRCS, NHCP
September 2008
2-205
-------
554-3
OPERATION AND MAINTENANCE
An Operation and Maintenance plan shall be
provided that identifies the intended purpose of
the practice, practice life safety requirements,
and water table elevations and periods of
operation necessary to meet the intended
purpose. If in-field water table observation
points are not used, the relationship of the
control elevation settings relative to critical field
water table depths shall be provided in the
operation plan.
The Operation and Maintenance Plan shall
include instructions for operation and
maintenance of critical components of the
drainage management system, including
instructions necessary to maintain flow
velocities within allowable limits when lowering
water tables.
To prevent leakage of liquid manure
applications into drain pipes, the plan shall
specify the elevation of the raised drainage
outlet and the number of days prior to and after
the application that a raised outlet elevation is
to be maintained.
Replace warped flashboards that cause
structure leakage.
REFERENCES
USDA, NRCS. 2001. National Engineering
Handbook, Part 624, Sec. 16, Drainage of
agricultural land.
USDA, NRCS. 2001. National Engineering
Handbook, Part 650, Engineering Field
Handbook, Chapter 14, Water management
(Drainage).
2-206
NRCS, NHCP
September 2008
-------
558- 1
NATURAL RESOURCES CONSERVATION SERVICE
CONSERVATION PRACTICE STANDARD
ROOF RUNOFF STRUCTURE
(No.)
CODE 558
DEFINITION
Structures that collect, control, and transport
precipitation from roofs.
PURPOSE
To improve water quality, reduce soil erosion,
increase infiltration, protect structures, and/or
increase water quantity.
CONDITIONS WHERE PRACTICE APPLIES
Where roof runoff from precipitation needs to be:
• diverted away from structures or
contaminated areas;
• collected, controlled, and transported to a
stable outlet; or
• collected and used for other purposes such
as irrigation or animal watering facility.
CRITERIA
General Criteria Applicable to All Purposes
The minimum design capacity for roof runoff
structures shall be a 10-year storm frequency,
5-minute rainfall precipitation event, except
where excluding roof runoff from manure
management facilities. In that case, a 25-year
frequency, 5-minute precipitation event shall be
used to design roof runoff structures (Refer to
Agricultural Waste Management Field
Handbook, NEH Part 651 Chapter 10 Appendix
10B). When gutters are used, the capacity of
the downspout(s) must equal or exceed the
gutter flow rate.
Runoff may empty into surface or underground
outlets, or onto the ground surface. Surface and
underground outlets shall be sized to ensure
adequate design capacity and shall provide for
clean-out as appropriate. When runoff from
roofs empties onto the ground surface, a stable
outlet shall be provided. When runoff is
conveyed through a gutter and downspout
system, an elbow and energy dissipation device
shall be placed at the end of the downspout to
provide a stable outlet and direct water away
from the building.
Surface or ground outlets such as rock pads,
rock filled trenches with subsurface drains,
concrete and other erosion-resistant pads, or
preformed channels may be used, particularly
where snow and ice are a significant load
component on roofs.
In regions where snow and ice will accumulate
on roofs, guards and sufficient supports to
withstand the anticipated design load shall be
included.
Roof runoff structures shall be made of durable
materials with a minimum design life often
years. Roof gutters and downspouts may be
made of aluminum, galvanized steel, wood, or
plastic. Aluminum gutters and downspouts shall
have a minimum nominal thickness of 0.027
inches and 0.020 inches, respectively.
Galvanized steel gutters and downspouts shall
be a minimum 28 gauge. Wood shall be clear
and free of knots. Wood may be redwood,
cedar, cypress, or other species that has the
desired longevity. Plastics shall contain
ultraviolet stabilizers. Dissimilar metals shall not
be in contact with each other.
Rock-filled trenches and pads shall consist of
poorly graded rock (all rock fragments
approximately the same size) and be free of
appreciable amounts of sand and/or soil
particles. Crushed limestone shall not be used
for backfill material unless it has been washed.
Subsurface drains or outlets shall meet the
Conservation practice standards are reviewed periodically and updated if needed. To obtain
the current version of this standard, contact your Natural Resources Conservation Service
State Office or visit the Field Office Technical Guide.
NRCS, NHCP
September 2009
2-207
-------
558-2
material requirements of the applicable NRCS
conservation practice standard.
Concrete appurtenances used shall meet the
requirements of NRCS NEH Part 642, Chapter
2, Construction Specification 32 Structure
Concrete.
Roof runoff structures shall be protected from
damage by livestock and equipment.
Additional Criteria to Increase Infiltration
Runoff shall be routed onto pervious landscaped
areas (e.g., lawns, mass planting areas,
infiltration trenches, and natural areas) to
increase infiltration of runoff. These areas shall
be capable of infiltrating the runoff in such a way
that replenishes soil moisture without adversely
affecting the desired plant species.
Additional Criteria to Protect Structures
Runoff shall be directed away from structure
foundations to avoid wetness and hydraulic
loading on the foundation.
On expansive soils or bedrock, downspout
extensions shall be used to discharge runoff a
minimum of five (5) feet from the structure.
The discharge area for runoff must slope away
from the protected structure.
Additional Criteria to Increase Water
Quantity
Storage structures for non-potable purposes
such as irrigation water shall be designed in
accordance with NRCS conservation practice
standards, as appropriate.
Potable water storage structures shall be
constructed of materials and in a manner that
will not increase the contamination of the stored
water. Roof runoff collected and stored for
potable uses must be treated prior to
consumption and shall be tested periodically to
assure that adequate quality is maintained for
human consumption.
CONSIDERATIONS
Avoid discharging outlets near wells and
sinkholes.
Some designs may provide secondary benefits,
e.g. rock pads may also reduce rodent problems
around livestock and poultry barns.
PLANS AND SPECIFICATIONS
The plans and specifications shall show the
location, spacing, size, and grade of all gutters
and downspouts and type and quality of material
to be used. Plans and specifications for other
practices essential to the proper functioning of
the roof runoff structure, such as underground
outlet, shall be included.
OPERATION AND MAINTENANCE
An operation and maintenance plan shall be
developed that is consistent with the purposes of
the practice, its intended life, safety
requirements, and the criteria for the design.
The plan shall contain, but not be limited to, the
following provisions:
• Keep roof runoff structures clean and free of
obstructions that reduce flow.
• Make regular inspections and perform repair
maintenance as needed to ensure proper
functioning of the roof runoff structures.
REFERENCES
USDA-NRCS. 1999. National Engineering
Handbook, Part 651, Agricultural Waste
Management Field Handbook.
NRCS, NHCP
September 2009
2-208
-------
590- 1
NATURAL RESOURCES CONSERVATION SERVICE
CONSERVATION PRACTICE STANDARD
NUTRIENT MANAGEMENT
(Ac.)
CODE 590
DEFINITION
Managing the amount, source, placement,
form and timing of the application of plant
nutrients and soil amendments.
PURPOSE
• To budget and supply nutrients for plant
production.
• To properly utilize manure or organic by-
products as a plant nutrient source.
• To minimize agricultural nonpoint source
pollution of surface and ground water
resources.
• To protect air quality by reducing nitrogen
emissions (ammonia and NOX compounds)
and the formation of atmospheric
particulates.
• To maintain or improve the physical,
chemical and biological condition of soil.
CONDITIONS WHERE PRACTICE APPLIES
This practice applies to all lands where plant
nutrients and soil amendments are applied.
CRITERIA
General Criteria Applicable to All Purposes
A nutrient budget for nitrogen, phosphorus,
and potassium shall be developed that
considers all potential sources of nutrients
including, but not limited to animal manure and
organic by-products, waste water, commercial
fertilizer, crop residues, legume credits, and
irrigation water.
Realistic yield goals shall be established based
on soil productivity information, historical yield
data, climatic conditions, level of management
and/or local research on similar soil, cropping
systems, and soil and manure/organic by-
products tests.
For new crops or varieties, industry yield
recommendations may be used until
documented yield information is available.
Plans for nutrient management shall specify
the source, amount, timing and method of
application of nutrients on each field to achieve
realistic production goals, while minimizing
movement of nutrients and other potential
contaminants to surface and/or ground waters.
Areas contained within established minimum
application setbacks (e.g., sinkholes, wells,
gullies, ditches, surface inlets or rapidly
permeable soil areas) shall not receive direct
application of nutrients.
The amount of nutrients lost to erosion, runoff,
irrigation and drainage, shall be addressed, as
needed.
Soil and Tissue Sampling and Laboratory
Analyses (Testing). Nutrient planning shall
be based on current soil and tissue (where
used as a supplement) test results developed
in accordance with Land Grant University
guidance, or industry practice if recognized by
the Land Grant University. Current soil tests
are those that are no older than five years.
Soil and tissue samples shall be collected and
prepared according to the Land Grant
University guidance or standard industry
practice. Soil and tissue test analyses shall be
performed by laboratories that are accepted in
one or more of the following:
Conservation practice standards are reviewed periodically and updated if needed. To obtain
the current version of this standard, contact your Natural Resources Conservation Service
State Office or visit the electronic Field Office Technical Guide.
NRCS, NHCP
August 2006
2-209
-------
590-2
• Laboratories successfully meeting the
requirements and performance standards
of the North American Proficiency Testing
Program (NAPT) under the auspices of the
Soil Science Society of America, or
• State recognized program that considers
laboratory performance and proficiency to
assure accuracy of soil test results.
Soil and tissue testing shall include analyses
for any nutrients for which specific information
is needed to develop the nutrient plan.
Request analyses pertinent to monitoring or
amending the annual nutrient budget, e.g. pH,
electrical conductivity (EC), soil organic matter,
nitrogen, phosphorus and potassium.
Nutrient Application Rates. Soil
amendments shall be applied, as needed, to
adjust soil pH to an adequate level for crop
nutrient availability and utilization.
Recommended nutrient application rates shall
be based on Land Grant University
recommendations (and/or industry practice
when recognized by the university) that
consider current soil test results, realistic yield
goals and management capabilities. If the
Land Grant University does not provide
specific recommendations, application shall be
based on realistic yield goals and associated
plant nutrient uptake rates.
The planned rates of nutrient application, as
documented in the nutrient budget, shall be
determined based on the following guidance:
• Nitrogen Application - Planned nitrogen
application rates shall match the
recommended rates as closely as
possible, except when manure or organic
by-products are a source of nutrients.
When manure or organic by-products are a
source of nutrients, see "Additional
Criteria" below.
• Phosphorus Application - Planned
phosphorus application rates shall match
the recommended rates as closely as
possible, except when manure or organic
by-products are sources of nutrients.
When manure or organic by-products are a
source of nutrients, see "Additional
Criteria" below.
NRCS, NHCP
August 2006
2-210
• Potassium Application - Potassium shall
not be applied in situations in which
excess (greater than soil test potassium
recommendation) causes unacceptable
nutrient imbalances in crops or forages.
When forage quality is an issue associated
with excess potassium application, state
standards shall be used to set forage
quality guidelines.
• Other Plant Nutrients - The planned rates
of application of other nutrients shall be
consistent with Land Grant University
guidance or industry practice if recognized
by the Land Grant University in the state.
• Starter Fertilizers - When starter fertilizers
are used, they shall be included in the
overall nutrient budget, and applied in
accordance with Land Grant University
recommendations, or industry practice if
recognized by the Land Grant University
within the state.
Nutrient Application Timing. Timing and
method of nutrient application (particularly
nitrogen) shall correspond as closely as
possible with plant nutrient uptake
characteristics, while considering cropping
system limitations, weather and climatic
conditions, risk assessment tools (e.g.,
leaching index, P index) and field accessibility.
Nutrient Application Methods. Application
methods to reduce the risk of nutrient transport
to surface and ground water, or into the
atmosphere shall be employed.
To minimize nutrient losses:
• Apply nutrient materials uniformly to
application area(s).
• Nutrients shall not be applied to frozen,
snow-covered or saturated soil if the
potential risk for runoff exists.
• Nutrients shall be applied considering the
plant growth habits, irrigation practices,
and other conditions so as to maximize
availability to the plant and minimize the
risk of runoff, leaching, and volatilization
losses.
• Nutrient applications associated with
irrigation systems shall be applied in a
manner that prevents or minimizes
resource impairment.
-------
590-3
Conservation Management Unit (CMU) Risk
Assessment. In areas with identified or
designated nutrient related water quality
impairment, a CMU specific risk assessment of
the potential for nutrient transport from the
area shall be completed.
States that utilize a threshold prescreening
procedure to trigger CMU risk assessment
shall follow approved procedures as
recommended by the respective state or Land
Grant University.
Use an appropriate nutrient risk assessment
tool for the nutrient in question (e.g., leaching
index, phosphorus index) or other state
recognized assessment tool.
Additional Criteria Applicable to Manure
and Organic By-Products or Biosolids
Applied as a Plant Nutrient Source
When animal manures or organic by-products
are applied, a risk assessment of the potential
for nutrient transport from the CMU shall be
completed to adjust the amount, placement,
form and timing of application of nutrient
sources, as recommended by the respective
state or Land Grant University.
Nutrient values of manure and organic by-
products (excluding sewage sludge or
biosolids) shall be determined prior to land
application. Samples will be taken and
analyzed with each hauling/emptying cycle for
a storage/treatment facility. Manure sampling
frequency may vary based on the operation's
manure handling strategy and spreading
schedule. If there is no prior sampling history,
the manure shall be analyzed at least annually
for a minimum of three consecutive years. A
cumulative record shall be developed and
maintained until a consistent (maintaining a
certain nutrient concentration with minimal
variation) level of nutrient values is realized.
The average of results contained in the
operation's cumulative manure analyses
history shall be used as a basis for nutrient
allocation to fields. Samples shall be collected
and prepared according to Land Grant
University guidance or industry practice.
In planning for new operations, acceptable
"book values" recognized by the NRCS and/or
the Land Grant University may be used if they
accurately estimate nutrient output from the
proposed operation (e.g., NRCS Agricultural
Waste Management Field Handbook).
Biosolids (sewage sludge) shall be applied in
accordance with USEPA regulations. (40 CFR
Parts 403 (Pretreatment) and 503 (Biosolids)
and other state and/or local regulations
regarding the use of biosolids as a nutrient
source.
Manure and Organic By-Product Nutrient
Application Rates. Manure and organic by-
product nutrient application rates shall be
based on nutrient analyses procedures
recommended by the respective state or Land
Grant University. As indicated above, "book
values" may be used in planning for new
operations. At a minimum, manure analyses
shall identify nutrient and specific ion
concentrations, percent moisture, and percent
organic matter. Salt concentration shall be
monitored so that manure applications do not
cause plant damage or negatively impact soil
quality.
The application rate (in/hr) of liquid materials
applied shall not exceed the soil
intake/infiltration rate and shall be adjusted to
minimize ponding and to avoid runoff. The total
application shall not exceed the field capacity
of the soil and shall be adjusted, as needed, to
minimize loss to subsurface tile drains.
The planned rates of nitrogen and phosphorus
application recorded in the plan shall be
determined based on the following guidance:
Nitrogen Application Rates
o When manure or organic by-products
are used, the nitrogen availability of
the planned application rates shall
match plant uptake characteristics as
closely as possible, taking into
consideration the timing of nutrient
application(s) in order to minimize
leaching and atmospheric losses.
o Management activities and
technologies shall be used that
effectively utilize mineralized nitrogen
and that minimize nitrogen losses
through denitrification and ammonia
volatilization.
NRCS, NHCP
August 2006
2-211
-------
590-4
o Manure or organic by-products may be
applied on legumes at rates equal to
the estimated removal of nitrogen in
harvested plant biomass.
o When the nutrient management plan
component is being implemented on a
phosphorus basis, manure or organic
by-products shall be applied at rates
consistent with a phosphorus limited
application rate. In such situations, an
additional nitrogen application, from
non-organic sources, may be required
to supply, but not exceed, the
recommended amounts of nitrogen in
any given year.
Phosphorus Application Rates
o When manure or organic by-products
are used, the planned rates of
phosphorus application shall be
consistent with any one of the
following options:
0 Phosphorus Index (PI) Rating.
Nitrogen-based manure
application on Low or Medium
Risk Sites; phosphorus-based or
no manure application on High
and Very High Risk Sites.**
0 Soil Phosphorus Threshold
Values. Nitrogen-based manure
application on sites on which the
soil test phosphorus levels are
below the threshold values;
Phosphorus-based or no manure
application on sites on which soil
phosphorus levels equal or exceed
threshold values.**
0 Soil Test. Nitrogen-based manure
application on sites for which the
soil test recommendation calls for
phosphorus application;
phosphorus-based or no manure
application on sites for which the
soil test recommendation calls for
no phosphorus application, t
** Acceptable phosphorus-
based manure application rates
shall be determined as a function
of soil test recommendation or
estimated phosphorus removal in
harvested plant biomass.
NRCS, NHCP
August 2006
2-212
Guidance for developing these
acceptable rates is found in the
NRCS General Manual, Title 190,
Part 402 (Ecological Sciences,
Nutrient Management, Policy), and
the National Agronomy Manual,
Section 503 (to be developed).
o The application of phosphorus applied
as manure may be made at a rate
equal to the recommended
phosphorus application or estimated
phosphorus removal in harvested plant
biomass for the crop rotation or
multiple years in the crop sequence.
When such applications are made, the
application rate shall:
0 Not exceed the recommended
nitrogen application rate during the
year of application, or
0 Not exceed the estimated nitrogen
removal in harvested plant
biomass during the year of
application when there is no
recommended nitrogen
application.
0 Not be made on sites considered
vulnerable to off-site phosphorus
transport unless appropriate
conservation practices, best
management practices or
management activities are used to
reduce the vulnerability.
Heavy Metal Monitoring. When sewage
sludge (biosolids) is applied, the accumulation
of potential pollutants (including arsenic,
cadmium, copper, lead, mercury, selenium,
and zinc) in the soil shall be monitored in
accordance with the US Code, Reference 40
CFR, Parts 403 and 503, and/or any applicable
state and local laws or regulations.
Additional Criteria to Protect Air Quality by
Reducing Nitrogen and/or Particulate
Emissions to the Atmosphere
In areas with an identified or designated
nutrient management related air quality
concern, any component(s) of nutrient
management (i.e., amount, source, placement,
form, timing of application) identified by risk
assessment tools as a potential source of
-------
590-5
atmospheric pollutants shall be adjusted, as
necessary, to minimize the loss(es).
When tillage can be performed, surface
applications of manure and fertilizer nitrogen
formulations that are subject to volatilization on
the soil surface (e.g., urea) shall be
incorporated into the soil within 24 hours after
application.
When manure or organic by-products are
applied to grassland, hayland, pasture or
minimum-till areas the rate, form and timing of
application(s) shall be managed to minimize
volatilization losses.
When liquid forms of manure are applied with
irrigation equipment, operators will select
weather conditions during application that will
minimize volatilization losses.
Operators will handle and apply poultry litter or
other dry types of animal manures when the
potential for wind-driven loss is low and there
is less potential for transport of particulates
into the atmosphere.
Weather and climatic conditions during manure
or organic by-product application(s) shall be
recorded and maintained in accordance with
the operation and maintenance section of this
standard.
Additional Criteria to Improve the Physical.
Chemical and Biological Condition of the
Soil
Nutrients shall be applied and managed in a
manner that maintains or improves the
physical, chemical and biological condition of
the soil.
Minimize the use of nutrient sources with high
salt content unless provisions are made to
leach salts below the crop root zone.
To the extent practicable nutrients shall not be
applied when the potential for soil compaction
and rutting is high.
CONSIDERATIONS
The use of management activities and
technologies listed in this section may improve
both the production and environmental
performance of nutrient management systems.
The addition of these management activities,
when applicable, increases the management
intensity of the system and is recommended in
a nutrient management system.
Action should be taken to protect National
Register listed and other eligible cultural
resources.
The nutrient budget should be reviewed
annually to determine if any changes are
needed for the next planned crop.
For sites on which there are special
environmental concerns, other sampling
techniques may be appropriate. These include
soil profile sampling for nitrogen, Pre-
Sidedress Nitrogen Test (PSNT), Pre-Plant
Soil Nitrate Test (PPSN) or soil surface
sampling for phosphorus accumulation or pH
changes.
Additional practices to enhance manure
management effectively include modification of
the animal's diet to reduce the manure nutrient
content, or utilizing manure amendments that
stabilize or tie-up nutrients.
Soil test information should be no older than
one year when developing new plans,
particularly if animal manures are to be used
as a nutrient source.
Excessive levels of some nutrients can cause
induced deficiencies of other nutrients.
If increases in soil phosphorus levels are
expected, consider a more frequent (annual)
soil testing interval.
To manage the conversion of nitrogen in
manure or fertilizer, use products or materials
(e.g. nitrification inhibitors, urease inhibitors
and slow or controlled release fertilizers) that
more closely match nutrient release and
availability for plant uptake. These materials
may improve the nitrogen use efficiency (NUE)
of the nutrient management system by
reducing losses of nitrogen into water and/or
air.
Considerations to Minimize Agricultural
Nonpoint Source Pollution of Surface and
Ground Water.
Erosion control and runoff reduction practices
can improve soil nutrient and water storage,
infiltration, aeration, tilth, diversity of soil
NRCS, NHCP
August 2006
2-213
-------
590-6
organisms and protect or improve water and
air quality (Consider installation of one or more
NRCS FOTG, Section IV - Conservation
Practice Standards).
Cover crops can effectively utilize and/or
recycle residual nitrogen.
Apply nutrient materials uniformly to the
application area. Application methods and
timing that reduce the risk of nutrients being
transported to ground and surface waters, or
into the atmosphere include:
• Split applications of nitrogen to provide
nutrients at the times of maximum crop
utilization,
• Use stalk-test to minimize risk of over
applying nitrogen in excess of crop needs.
• Avoid winter nutrient application for spring
seeded crops,
• Band applications of phosphorus near the
seed row,
• Incorporate surface applied manures or
organic by-products as soon as possible
after application to minimize nutrient
losses,
• Delay field application of animal manures
or organic by-products if precipitation
capable of producing runoff and erosion is
forecast within 24 hours of the time of the
planned application.
Considerations to Protect Air Quality by
Reducing Nitrogen and/or Particulate
Emissions to the Atmosphere.
Odors associated with the land application of
manures and organic by-products can be
offensive to the occupants of nearby homes.
Avoid applying these materials upwind of
occupied structures when residents are likely
to be home (evenings, weekends and
holidays).
When applying manure with irrigation
equipment, modifying the equipment can
reduce the potential for volatilization of
nitrogen from the time the manure leaves the
application equipment until it reaches the
surface of the soil (e.g., reduced pressure,
drop down tubes for center pivots). N
volatilization from manure in a surface
irrigation system will be reduced when applied
under a crop canopy.
When planning nutrient applications and tillage
operations, encourage soil carbon buildup
while discouraging greenhouse gas emissions
(e.g., nitrous oxide N2O, carbon dioxide CO2).
Nutrient applications associated with irrigation
systems should be applied in accordance with
the requirements of Irrigation Water
Management (Code 449).
CAFO operations seeking permits under
USEPA regulations (40 CFR Parts 122 and
412) should consult with their respective state
permitting authority for additional criteria.
PLANS AND SPECIFICATIONS
Plans and specifications for nutrient
management shall be in keeping with this
standard and shall describe the requirements
for applying the practice to achieve its intended
purpose(s), using nutrients to achieve
production goals and to prevent or minimize
resource impairment.
Nutrient management plans shall include a
statement that the plan was developed based
on requirements of the current standard and
any applicable Federal, state, or local
regulations, policies, or programs, which may
include the implementation of other practices
and/or management activities. Changes in any
of these requirements may necessitate a
revision of the plan.
The following components shall be included in
the nutrient management plan:
• aerial site photograph(s) or site map(s),
and a soil survey map of the site,
• location of designated sensitive areas or
resources and the associated, nutrient
management restriction,
• current and/or planned plant production
sequence or crop rotation,
• results of soil, water, manure and/or
organic by-product sample analyses,
• results of plant tissue analyses, when used
for nutrient management,
• realistic yield goals for the crops,
NRCS, NHCP
August 2006
2-214
-------
590-7
• complete nutrient budget for nitrogen,
phosphorus, and potassium for the crop
rotation or sequence,
• listing and quantification of all nutrient
sources,
• CMU specific recommended nutrient
application rates, timing, form, and method
of application and incorporation, and
• guidance for implementation, operation,
maintenance, and recordkeeping.
If increases in soil phosphorus levels are
expected, the nutrient management plan shall
document:
• the soil phosphorus levels at which it may
be desirable to convert to phosphorus
based planning,
• results of appropriate risk assessment
tools to document the relationship between
soil phosphorus levels and potential for
phosphorus transport from the field,
• the potential for soil phosphorus drawdown
from the production and harvesting of
crops, and
• management activities or techniques used
to reduce the potential for phosphorus
loss.
OPERATION AND MAINTENANCE
The owner/client is responsible for safe
operation and maintenance of this practice
including all equipment. Operation and
maintenance addresses the following:
• periodic plan review to determine if
adjustments or modifications to the plan
are needed. As a minimum, plans will be
reviewed and revised with each soil test
cycle.
• significant changes in animal numbers
and/or feed management will necessitate
additional manure sampling and analyses
to establish a revised average nutrient
content.
• protection of fertilizer and organic by-
product storage facilities from weather and
accidental leakage or spillage.
• calibration of application equipment to
ensure uniform distribution of material at
planned rates.
• documentation of the actual rate at which
nutrients were applied. When the actual
rates used differ from the recommended
and planned rates, records will indicate the
reasons for the differences.
• Maintaining records to document plan
implementation. As applicable, records
include:
o Soil, plant tissue, water, manure, and
organic by-product analyses resulting
in recommendations for nutrient
application,
o quantities, analyses and sources of
nutrients applied,
o dates and method(s) of nutrient
applications,
o weather conditions and soil moisture
at the time of application; lapsed time
to manure incorporation, rainfall or
irrigation event.
o crops planted, planting and harvest
dates, yields, and crop residues
removed,
o dates of plan review, name of
reviewer, and recommended changes
resulting from the review.
Records should be maintained for five years;
or for a period longer than five years if required
by other Federal, state or local ordinances, or
program or contract requirements.
Workers should be protected from and avoid
unnecessary contact with plant nutrient
sources. Extra caution must be taken when
handling ammoniacal nutrient sources, or
when dealing with organic wastes stored in
unventilated enclosures.
Material generated from cleaning nutrient
application equipment should be utilized in an
environmentally safe manner. Excess material
should be collected and stored or field applied
in an appropriate manner.
Nutrient containers should be recycled in
compliance with state and local guidelines or
regulations.
NRCS, NHCP
August 2006
2-215
-------
590-8
REFERENCES Sims, J.T. (ed.) 2005. Phosphorus: Agriculture
c N « n c onn-i M-* -r ( *• anc' tne Environment. Agron. Monogr. 46.
Foett, R.F. 2001. Nitrogen Transformation AOA -00. ^OOOA «« ^- IA«
. T' . _. M ^-7^,i-,i- ASA, CSSA, and SSSA, Madison, Wl.
and Transport Processes, pp. 17-44, In R.F.
Follett and J. Hatfield. (eds.). 2001. Nitrogen Stevenson, F.J. (ed.) 1982. Nitrogen in
in the Environment; Sources, Problems, and Agricultural Soils. Agron. Series 22. ASA,
Solutions. Elsevier Science Publishers. The CSSA, and SSSA, Madison, Wl.
Netherlands. 520 pp.
NRCS, NHCP
August 2006
2-216
-------
614- 1
NATURAL RESOURCES CONSERVATION SERVICE
CONSERVATION PRACTICE STANDARD
WATERING FACILITY
(No.)
CODE 614
DEFINITION
A permanent or portable device to provide an
adequate amount and quality of drinking water
for livestock and or wildlife.
PURPOSE
To provide access to drinking water for
livestock and/or wildlife in order to:
• Meet daily water requirements
• Improve animal distribution
CONDITIONS WHERE PRACTICE APPLIES
This practice applies to all land uses where
there is a need for new or improved watering
facilities for livestock and/or wildlife.
CRITERIA
General Criteria Applicable To All Purposes
Design watering facilities with adequate
capacity and supply to meet the daily water
requirements of the livestock and/or wildlife
planned to use the facility. Include the storage
volume necessary to provide water between
periods of replenishment. Refer to the
National Range and Pasture Handbook for
guidance on livestock water quantity and
quality requirements. For wildlife, base water
quantity and quality requirements on targeted
species needs.
Locate facilities to promote even grazing
distribution and reduce grazing pressure on
sensitive areas.
Design the watering facility to provide
adequate access to the animals planned to
use the facility. Incorporate escape features
into the watering facility design where local
knowledge and experience indicate that wildlife
may be at risk of drowning.
Include design elements to meet the specific
needs of the animals that are planned to use
the watering facility, both livestock and wildlife.
Protect areas around watering facilities where
animal concentrations or overflow from the
watering facility will cause resource concerns.
Use criteria in NRCS Conservation Practice
Standard 561, Heavy Use Area Protection to
design the protection.
Install permanent watering facilities on a firm,
level, foundation that will not settle
differentially. Examples of suitable foundation
materials are bedrock, compacted gravel and
stable, well compacted soils.
Design and install watering facilities to prevent
overturning by wind and animals.
Design watering facilities and all valves and
controls to withstand or be protected from
damage by livestock, wildlife, freezing and ice
damage.
Construct watering facilities from durable
materials that have a life expectancy that
meets or exceeds the planned useful life of the
installation. Follow appropriate NRCS design
procedures for the material being used or
industry standards where NRCS standards do
not exist.
Use the criteria in NRCS Conservation
Practice Standard 516, Pipeline to design
piping associated with the watering facility.
Include backflow prevention devices on
facilities connected to wells, domestic or
municipal water systems.
Conservation practice standards are reviewed periodically, and updated if needed. To obtain
the current version of this standard, contact your Natural Resources Conservation Service
State Office, or download it from the electronic Field Office Technical Guide.
NRCS, NHCP
August 2006
2-217
-------
614-2
CONSIDERATIONS
Design fences associated with the watering
facilities to allow safe access and exit for area
wildlife species. To protect bats and other
species that access water by skimming across
the surface, fencing material should not extend
across the water surface. If fencing across the
water is necessary it should be made highly
visible by avoiding the use of single wire
fences and using fencing materials such as
woven wire or by adding streamers or
coverings on the fence.
For watering facilities that will be accessible to
wildlife, give consideration to the effects the
location of the facility will have on target and
non-target species. Also consider the effect of
introducing a new water source within the
ecosystem in the vicinity of the facility. This
should include things such as the
concentration of grazing, predation,
entrapment, drowning, disease transmission,
hunting and expansion of the wildlife
populations beyond the carrying capacity of
available habitat.
Consider the following guidelines for materials
commonly used for watering facilities.
Concrete
Galvanized
Steel
Plastic
Fiberglass
3000 psi compressive
strength
20 gauge thickness
Ultraviolet resistance
Ultraviolet resistance
Where water is supplied continuously or under
pressure to the watering facility consider the
use of automatic water level controls to control
the flow of water to the facility and to prevent
unnecessary overflows.
Watering facilities often collect debris and
algae and should be cleaned on a regular
basis. Consider increasing the pipe sizes for
inlets and outlets to reduce the chances of
clogging. Maintenance of a watering facility
can be made easier by providing a method to
completely drain the watering facility.
Steep slopes leading to watering facilities can
cause erosion problems from over use by
animals as well as problems with piping and
valves from excess pressure. Choose the
location of watering facilities to minimize these
problems from steep topography.
PLANS AND SPECIFICATIONS
Plans and specifications for watering facilities
shall provide the information necessary to
install the facility. As a minimum this shall
include the following:
• A map or aerial photograph showing the
location of the facility
• Detail drawings showing the facility,
necessary appurtenances (such as
foundations, pipes and valves) and
stabilization of any areas disturbed by the
installation of the facility
• Construction specifications describing the
installation of the facility
OPERATION AND MAINTENANCE
Provide an O&M plan specific to the type of
watering facility, to the landowner. As a
minimum include the following items in the
plan:
• a monitoring schedule to ensure
maintenance of adequate inflow and
outflow;
• checking for leaks and repair as
necessary;
• if present, the checking of the automatic
water level device to insure proper
operation;
• checking to ensure that adjacent areas are
protected against erosion;
• if present, checking to ensure the outlet
pipe is freely operating and not causing
erosion problems;
• a schedule for periodic cleaning of the
facility.
NRCS, NHCP
August 2006
2-218
-------
614-3
REFERENCES
Brigham, William and Stevenson, Craig, 1997,
Wildlife Water Catchment Construction in
Nevada, Technical Note 397.
Tsukamoto, George and Stiver, San Juan,
1990j_Wildlife water Development,
Proceedings of the Wildlife Water
Development Symposium, Las Vegas, NV,
USDI Bureau of Land Management.
Yoakum, J. and W.P. Dasmann. 1971. Habitat
manipulation practices. Ch. 14 in Wildlife
Management Techniques, Third Edition. Ed.
Robert H. Giles, Jr. Pub. The Wildlife Society.
633 pp.
National Engineering Handbook, Part 650
Engineering Field Handbook, Chapters 5, 11 &
12, USDA Natural Resources Conservation
Service.
National Range and Pasture Handbook,
Chapter 6, Page 6-12, Table 6-7 & 6-8, USDA-
Natural Resources Conservation Service.
National Research Council, 1996 Nutrient
Requirements of Domestic Animals, National
Academy Press.
NRCS, NHCP
August 2006
2-219
-------
633- 1
NATURAL RESOURCES CONSERVATION SERVICE
CONSERVATION PRACTICE STANDARD
WASTE UTILIZATION
(Ac.)
CODE 633
DEFINITION
Using agricultural wastes such as manure and
wastewater or other organic residues.
PURPOSE
• Protect water quality
• Protect air quality
• Provide fertility for crop, forage, fiber
production and forest products
• Improve or maintain soil structure
• Provide feedstock for livestock
• Provide a source of energy
CONDITIONS WHERE PRACTICE APPLIES
This practice applies where agricultural wastes
including animal manure and contaminated
water from livestock and poultry operations;
solids and wastewater from municipal
treatment plants; and agricultural processing
residues are generated, and/or utilized
CRITERIA
General Criteria Applicable to All Purposes
All federal, state and local laws, rules and
regulations governing waste management,
pollution abatement, health and safety shall be
strictly adhered to. The owner or operator
shall be responsible for securing all required
permits or approvals related to waste
utilization, and for operating and maintaining
any components in accordance with applicable
laws and regulations.
Use of agricultural wastes shall be based on at
least one analysis of the material during the
time it is to be used. In the case of daily
spreading, the waste shall be sampled and
analyzed at least once each year. As a
minimum, the waste analysis should identify
nutrient and specific ion concentrations.
Where the metal content of municipal
wastewater, sludge, septage and other
agricultural waste is of a concern, the analysis
shall also include determining the
concentration of metals in the material.
When agricultural wastes are land applied,
application rates shall be consistent with the
requirements of the NRCS conservation
practice standard for nutrient management
(590).
Where agricultural wastes are to be spread on
land not owned or controlled by the producer,
the waste management plan, as a minimum,
shall document the amount of waste to be
transferred and who will be responsible for the
environmentally acceptable use of the waste.
Records of the use of wastes shall be kept a
minimum of five years as discussed in
OPERATION AND MAINTENANCE, below.
Additional Criteria to Protect Water Quality
All agricultural waste shall be utilized in a
manner that minimizes the opportunity for
contamination of surface and ground water
supplies.
Agricultural waste shall not be land-applied on
soils that are frequently flooded, as defined by
the National Cooperative Soil Survey, during
the period when flooding is expected.
When liquid wastes are applied, the application
rate shall not exceed the infiltration rate of the
soil, and the amount of waste applied shall not
exceed the moisture holding capacity of the
Conservation practices are reviewed periodically, and updated if needed. To obtain the
current version of this standard, contact the Natural Resources Conservation Service.
NRCS, NHCP
October 2003
2-220
-------
633-2
soil profile at the time of application. Wastes
shall not be applied to frozen, snow-covered or
saturated soil if the potential risk for runoff
exists. The basis for the decision to apply
waste under these conditions shall be
documented in the waste management plan.
Additional Criteria to Protect Air Quality
Incorporate surface applications of solid forms
of manure or other organic by-products into the
soil within 24 hours of application to minimize
emissions and to reduce odors.
When applying liquid forms of manure with
irrigation equipment select application
conditions where there is high humidity,
little/no wind blowing, a forthcoming rainfall
event and/or other conditions that will minimize
volatilization losses into the atmosphere. The
basis for applying manure under these
conditions shall be documented in the nutrient
management plan.
Handle and apply poultry litter or other dry
types of animal manure or other organic by-
products when weather conditions are calm
and there is less potential for blowing and
emission of particulates in the atmosphere.
The basis for applying manure under these
conditions shall be documented in the nutrient
management plan.
When sub-surface applied using an injection
system, waste shall be placed at a depth and
applied at a rate that minimizes leaks onto the
soil surface, while minimizing disturbance to
the soil surface and plant community.
All materials shall be handled in a manner to
minimize the generation of particulate matter,
odors and greenhouse gases.
Additional Criteria for Providing Fertility for
Crop. Forage and Fiber Production and
Forest Products
Where agricultural wastes are utilized to
provide fertility for crop, forage, fiber
production and forest products, the practice
standard Nutrient Management (590) shall be
followed.
Where municipal wastewater and solids are
applied to agricultural lands as a nutrient
source, the single application or lifetime limits
of heavy metals shall not be exceeded. The
concentration of salts shall not exceed the
NRCS, NHCP
October 2003
level that will impair seed germination or plant
growth.
Additional Criteria for Improving or
Maintaining Soil Structure
Wastes shall be applied at rates not to exceed
the crop nutrient requirements or salt
concentrations as stated above.
Residue management practices shall be used
for maintenance of soil structure.
Additional Criteria for Providing Feedstock
for Livestock
Agricultural wastes to be used for feedstock
shall be handled in a manner to minimize
contamination and preserve its feed value.
Chicken litter stored for this purpose shall be
covered. A qualified animal nutritionist shall
develop rations that utilize wastes.
Additional Criteria for Providing a Source
of Energy
Use of agricultural waste for energy production
shall be an integral part of the overall waste
management system.
All energy producing components of the
system shall be included in the waste
management plan and provisions for utilization
of residues of energy production identified.
Where the residues of energy production are
to be land-applied for crop nutrient use or soil
conditioning, the criteria listed above shall
apply.
CONSIDERATIONS
The effect of Waste Utilization on the water
budget should be considered, particularly
where a shallow ground water table is present
or in areas prone to runoff. Limit waste
application to the volume of liquid that can be
stored in the root zone.
Agricultural wastes contain pathogens and
other disease-causing organisms. Wastes
should be utilized in a manner that minimizes
their disease potential.
Priority areas for land application of wastes
should be on gentle slopes located as far as
possible from waterways. When wastes are
applied on more sloping land or land adjacent
to waterways, other conservation practices
2-221
-------
633-3
should be installed to reduce the potential for
offsite transport of waste.
It is preferable to apply wastes on pastures
and hayland soon after cutting or grazing
before re-growth has occurred.
Minimize environmental impact of land-applied
waste by limiting the quantity of waste applied
to the rates determined using the practice
standard Nutrient Management (590) for all
waste utilization.
Consider the net effect of waste utilization on
greenhouse gas emissions and carbon
sequestration.
PLANS AND SPECIFICATIONS
Plans and specifications for Waste Utilization
shall be in keeping with this standard and shall
describe the requirements for applying the
practice to achieve its intended purpose. The
waste management plan is to account for the
utilization or other disposal of all animal wastes
produced, and all waste application areas shall
be clearly indicated on a plan map.
OPERATION AND MAINTENANCE
Records shall be kept for a period of five years
or longer, and include when appropriate:
• Quantity of manure and other agricultural
waste produced and their nutrient content.
• Soil test results.
• Dates and amounts of waste application
where land applied, and the dates and
amounts of waste removed from the
system due to feeding, energy production
or export from the operation.
• Describe climatic conditions during waste
application such as: time of day,
temperature, humidity, wind speed, wind
direction and other factors as necessary.
• Waste application methods.
• Crops grown and yields (both yield goals
and measured yield).
• Other tests, such as determining the
nutrient content of the harvested product.
• Calibration of application equipment.
The operation and maintenance plan shall
include the dates of periodic inspections and
maintenance of equipment and facilities used
in waste utilization. The plan should include
what is to be inspected or maintained, and a
general time frame for making necessary
repairs.
2-222
NRCS, NHCP
October 2003
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
Appendix 2: Agricultural Tools in Support of
Section 502 Technical Guidance
Included in this appendix are summaries of online tools that can be used to develop plans for
these practices.
A range of information and expertise is available to help in developing management plans for
agricultural lands, including information derived from USDA, universities, soil and water
conservation districts, agricultural producers, and the private sector. A range of tools and
resources are summarized in the table below and represent those that are generally used by
experts (e.g., USDA field technicians and engineers) to work with clients to design appropriate
conservation plans for their lands. Most of the tools listed below are available for free.
#
Tool name and document link
Applicable practices3
Source and Web link
1. Software and Models
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
NuMan Pro
Animal Waste Management Software
Manure Management Planner (MMP)
Software
National Nutrient Management Data
Download
Spatial Nutrient Management Planner
Win Max
MapWindow CIS + MMP Tools
Revised Universal Soil Loss Equation,
Version 2 (RUSLE2)
Using RUSLE2 for the Design and
Predicted Effectiveness of Vegetative
Filter Strips (VFS) for Sediment
Vegetative Filter Strip Modeling System
(VFSMOD)
Integrated Farm System Model (IFSM)
Dairy Greenhouse Gas Model
(DairyGHG)
Cropware
Soil Test Conversion Tools
Great Plains Framework for Agricultural
Resource Management (GPFARM)
NM
AWM
AWM
AWM
NM, AWM
NM, AWM
AWM
ESC
ESC
ESC
ESC
ESC
NM,AWM
NM
NM,AWM
Univ. Maryland
USDA-NRCS
Purdue University
Univ. Missouri
Univ. Missouri
Purdue University
Purdue University
USDA-NRCS
USDA-NRCS
Univ. Florida
USDA-ARS
USDA-ARS
Cornell University
Cornell University
USDA-ARS
Chapter 2. Agriculture
2-223
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
#
16
Tool name and document link
Soil - Plant - Atmosphere — Water Field &
Pond Hydrology (SPAW)
Applicable practices3
NM
Source and Web link
USDA-ARS
II. Calculators, Spreadsheets, and Graphical Tools
17
18
19
20
21
22
23
24
25
26
27
Dairy Cattle N Excretion Calculator
Corn N Calculator
Total N Available from Manure
Applications
Other Calculators
Nutrient Management Spreadsheets
Crop Nutrient Tool
Crop Fertilizer Recommendation
Calculator
Manure Nutrient Availability Calculator
Conservation Buffers
Farm*A*Syst
Virginia Phosphorus Index
AWM, NM, ESC, GM
DWM
NM
NM
AWM, NM
NM
NM
NM
NM
AWM, NM
NM
Cornell University
Cornell University
Cornell University
Cornell University
Univ. of Delaware
USDA-NRCS
Purdue University
Purdue University
USDA NAG
Univ. of Wisconsin
Virginia Tech
III. Compilations of Tools
28
29
30
31
Technical Resources Main Page
Animal Feeding Operations (AFO) Virtual
Information Center
Software Products
Nutrient Management Planning Software
and Support
AWM, NM
AWM, DWM, ESC, GM,
NM
AWM, DWM, ESC, GM,
NM
NM, AWM
USDA NRCS
USEPA
USDA-ARS
Univ. Missouri
IV. Guidance and Other Technical Resources
32
33
34
35
36
37
38
39
40
Nutrient and Pest Management Tools and
Information
Conservation Practices
Agronomy and Erosion
Animal Feeding Operations
Nutrient Management Technical Notes
National Range and Pasture Handbook
Phosphorus Index
SERA-17 Publications and BMP Fact
Sheets
Managing Cover Crops Profitably, 3rd
Edition
NM
AWM, DWM, ESC, GM,
NM
ESC
AWM, NM
NM, AWM
GM, ESC
NM
NM
Cover Crops
USDA-NRCS
USDA-NRCS
USDA-NRCS
USDA-NRCS
USDA-NRCS
USDA-NRCS
USDA-NRCS
SERA-17
SARE
2-224
Chapter 2. Agriculture
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
#
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
Tool name and document link
Precision Feed Management Certification
for Dairy Professionals
Mid-Atlantic Better Composting School
Environmental Management System for
Manure
Mid-Atlantic Nutrient Management
Handbook
Information on Nutrient and Sediment
Best Management Practices
Fact Sheets
Nutrient Management
Nutrient Management Program
Nutrient Management Plan Writing Tools
Phosphorus Site Index
Nutrient Management Software and
Publications
Nutrient Management Spear Program
Manure Management
Pennsylvania Nutrient Management
Program
Planning Tools and Resources
Nutrient Management Technical Manual
Educational Materials
Fact Sheets on Agriculture and
Environmental Quality
Virginia Agricultural BMP Cost Share and
Tax Credit Programs
Nutrient and Waste Management
Comprehensive Livestock Environmental
Assessments and Nutrient (CLEANEast)
Management Plan program
Comprehensive Nutrient Management
Planning (CNMP)
CNMP Core Curriculum
Manure Management Planner Tutorials
Applicable practices3
AWM, NM
AWM, NM
AWM
NM
NM, ESC
NM,AWM
NM
NM
NM
NM
NM
AWM, NM
AWM, NM
NM
NM
NM,AWM
NM,AWM
NM, AWM, GM
AWM, DWM, ESC, GM,
NM
NM, AWM
NM, AWM
NM,AWM
NM, AWM, ESC, GM
AWM, NM
Source and Web link
Mid-Atlantic Water
Program
Mid-Atlantic Water
Program
Mid-Atlantic Water
Program
Mid-Atlantic Water
Program
Chesapeake Bay Program
Univ. Delaware
MD Dept. Agriculture
Univ. Maryland
Univ. Maryland
Univ. Maryland
Univ. Maryland
Cornell Univ.
Penn State Univ.
Penn State Univ.
Penn State Univ.
Penn State Univ.
Penn State Univ.
Virginia Tech Univ.
Virginia Dept.
Conservation and
Recreation
Univ. West Virginia
RTI International and North
Carolina State Univ.
extension
Iowa State Univ.
Univ. Missouri
Note:
a. AWM = animal waste management, DWM = drainage water management, ESC = erosion and sediment control,
GM = grazing management, NM=nutrient management
Chapter 2. Agriculture
2-225
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
I. Software and Models
1. Nutrient Management Planning (NMP) Software for Professionals (NuMan Pro)—
Univ. Maryland Extension
Nutrient Management for Maryland Professional Edition (NuMan Pro) is an integrated software
program that permits comprehensive NMP. The Maryland Phosphorus Site Index (PSI) has
been integrated into the program so that warnings are given when a PSI calculation could be
required based on soil test results. A simplified version of the Revised Universal Soil Loss
Equation (RUSLE) model to predict soil erosion losses has been included in the program in
support of the Maryland PSI assessment. Values for rainfall erosivity (R) and soil erodibility (K)
factors are determined from field location and soils information entered in the initial portions of
the program. Soil slope/steepness (LS), cropping management (C), and conservation
management (P) factors are determined from simplified user inputs. Part A and Part B of the
Maryland PSI are presented in a color-code scheme for user ease. Once slopes have been
identified in the field, it is estimated that an experienced user can determine the Maryland PSI in
less than 10 minutes.
Link: http://anmp.umd.edu/numan/numanpro.htm Accessed January 28, 2010
2. Animal Waste Management Software—USDA-NRCS
AWM 2.4.0, like the previous version, is a planning/design tool for animal feeding operations
that can be used to estimate the production of manure, bedding, and process water and
determine the size of storage/treatment facilities. The procedures and calculations used in AWM
are based on the USDA-NRCS Agricultural Waste Management Field Handbook.
The AWM has been upgraded with the capability to evaluate existing facilities. The results from
the evaluation are incorporated into the design processes for new facilities. The user can design
the new facility either for the Additional waste not handled by the existing facility, or for the Total
waste flowing into the structure.
The evaluation process involves the user entering the basic dimensions of an existing storage
facility along with other parameters such as herd size, local climatic condition (monthly rainfall),
and details about the additions such as bedding, wash water and flush water. With these inputs
the system estimates the total waste flowing into the structure identified in the management
train for the selected storage period and compares it the available storage volume. It then
presents an on-screen color coded report (red for inadequate and the green for the adequate
structure.) This report helps recognize if the structure is adequately designed or not easily and
quickly. The user can also print a hardcopy of this report.
2-226 Chapter 2. Agriculture
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
The AWM process of evaluating existing structures can help producers in deciding if they would
like to go for the No Discharge declaration within the EPA 2008 CAFO rule. The facility design
for the Total waste or for the Additional waste not handled by the existing structure is easily
done by selecting the appropriate radio button on the AWM design screen. In addition, several
improvements and bug fixes, listed below, have been incorporated to further improve AWM
functions and capabilities.
Link: http://www.wsi.nrcs.usda.gov/products/W2Q/AWM/pgrm24.html Accessed January 22,
2010
3. Manure Management Planner (MMP) Software—Purdue University
Manure Management Planner (MMP) is a Windows-based computer program developed at
Purdue University that is used to create manure management plans for crop and animal feeding
operations. The user enters information about the operation's fields, crops, storage, animals,
and application equipment. MMP helps the user allocate manure (where, when and how much)
on a monthly basis for the length of the plan (1-10 years). This allocation process helps
determine if the current operation has sufficient crop acreage, seasonal land availability, manure
storage capacity, and application equipment to manage the manure produced in an
environmentally responsible manner. MMP is also useful for identifying changes that could be
needed for a non-sustainable operation to become sustainable, and determine what changes
might be needed to keep an operation sustainable if the operation expands.
MMP supports 34 states including Delaware, Maryland, and Pennsylvania (support for Virginia
is underway), by automatically generating fertilizer recommendations and estimating manure N
availability based on each state's Extension and/or NRCS guidelines. It should be noted,
however, that MMP is not generally used in Maryland. Questions about MMP can be addressed
to the authors using contact information provided at the Web site.
Link: http://www.agry.purdue.edu/mmp/ Accessed January 22, 2010
4. National Nutrient Management Data Download—Univ. of Missouri Extension
The data download Web site helps to address nutrient management software data requirements
by providing a way for users to locate the farm of interest, define an area of interest and submit
a data request.
• The Spatial Nutrient Management Planner (SNMP) requires geo-referenced aerial
photographs, data from the soils survey, a topographic map and state-specific data on
manure application setback requirements.
Chapter 2. Agriculture 2-227
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
• Manure Management Planner (MMP) needs data from the soils survey and crop and
climatology data from Natural Resource Conservation Service (NRCS).
• The data download also includes data needed by the Revised Soil Loss Equation
version 2 (RUSLE(2)).
The data-finder packages the data in a compressed file that can be downloaded onto a
computer hard drive. The file is then un-compressed in the same folder on the computer the
holds the working SNMP and MMP files for that farm. This tool will generate a ZIP file containing
the aerial photo image, topographic map image, and soils data needed for SNMP, MMP and
RUSLE(2). The data is obtained from various USDA-NRCS data servers for any area with
spatial data in the NRCS Soils Data Mart (see Status Map). Google Maps is used to locate
farms and define a download area which includes the farm.
Link: http://www.nmplanner.missouri.edu/software/national data.asp Accessed January 22,
2010
5. Spatial Nutrient Management Planner—Univ. of Missouri Extension
The Spatial Nutrient Management Planner (SNMP) is a decision support tool that facilitates the
collection, analysis and presentation of spatial data related to NMP. Capabilities of SNMP
include:
• The SNMP interface simplifies the GIS program ArcMap for nutrient management
planners.
• With a click of a mouse, data can be imported and exported from Purdue's Manure
Management Planner (MMP).
• SNMP simplifies the creation of maps required for NRCS comprehensive nutrient
management plans
• Compatibility with NRCS Toolkit 9.x.
Link: http://proiects.cares.missouri.edu/snmp/nrcsdata/aoilist.aspAccessed January 22, 2010
6. Win Max—Purdue University
WinMax is a computer program developed at Purdue University to calculate and compare
economic returns on crop production. WinMax manages crop input data, calculates crop
fertilizer recommendations, generates production cost and nutrient management worksheets,
and allows sets of custom input costs to be created and used in all calculations. WinMax
supports the import of data from a manure management plan created with MMP, as well as the
2-228 Chapter 2. Agriculture
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
export of WinMax data to an MMP plan. Various management options, such as tillage, pest
control and fertilizer strategies, can be compared to help assess which practices are both
economically efficient and environmentally sound.
Link: http://www.agry.purdue.edu/max/Accessed January 22, 2010
7. MapWindow GIS + MMP Tools—Purdue University
MapWindow GIS + MMP Tools is a free GIS that can be used as a front-end to MMP and
WinMax.
Link: http://www.agry.purdue.edu/mmp/mapwindow/Accessed January 22, 2010
8. Revised Universal Soil Loss Equation, Version 2 (RUSLE2)—USDA-NRCS
This site contains the official NRCS version of RUSLE2. It is the only version of RUSLE2 to be
used for official purposes by NRCS field offices. The NRCS developed and maintains the
database components on this site.
RUSLE2 is an upgrade of the text-based RUSLE DOS version 1. It is a computer model
containing both empirical and process-based science in a Windows environment that predicts rill
and interrill erosion by rainfall and runoff. The USDA-Agricultural Research Service (ARS) is the
lead agency for developing the RUSLE2 model. The ARS, through university and private
contractors, is responsible for developing the science in the model and the model interface.
Link: http://fargo.nserl.purdue.edu/rusle2 dataweb/RUSLE2 lndex.htm Accessed January 22,
2010
9. Using RUSLE2forthe Design and Predicted Effectiveness of Vegetative Filter Strips
(VFS) for Sediment—USDA-NRCS
The Revised Universal Soil Loss Equation, Version 2, (RUSLE2) can also be used to design
and predict the expected lifespan of a VFS designed for the purpose of sediment removal based
on the procedures developed by Dillaha and Hayes. The following information is needed:
• Sediment delivery rate at the upper edge of the VFS for the contributing area to the
VFS—calculated by RUSLE2 using the overland flow slope length.
• Sediment Trapping Efficiency—calculated from RUSLE2 results.
• Ratio of Contributing Area to VFS Area.
Chapter 2. Agriculture 2-229
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
This publication requires Microsoft Excel and uses the following spreadsheet:
Filter Strip Life Span Design for Sediment (XLS; 24 KB)
Link: http://directives.sc.egov.usda.gov/OpenNonWebContent.aspx?content=18578.wba
Accessed January 22, 2010
Additional Reference: USDA-NRCS. 2007. Agronomy Technical Note No. 2, Using RUSLE2 for
the Design and Predicted Effectiveness of Vegetative Filter Strips (VFS) for Sediment, 8pp.
10. Vegetative Filter Strip Modeling System (VFSMOD)—University of Florida
VFSMOD-W is a design-oriented vegetative filter strip modeling system. The MS-Windows
graphical user interface (GUI) integrates the numerical model VFSMOD, a utility to generate
source (upslope disturbed area) inputs for the model based on readily available NRCS site
characteristics (UH), and advanced uncertainty and sensitivity analysis, inverse calibration and
design menu-driven components. VFSMOD, the core of the modeling system, is a computer
simulation model created to study hydrology, sediment and pollutant transport through
vegetative filter strips (VFS). The model is targeted at studying VFS performance on an event-
by-event basis and when combined with the upslope source area input preparation utility (UH or
others like PRZM), becomes a powerful and objective VFS design tool. The design paradigm
implemented in VFSMOD-W seeks to identify optimal filter constructive characteristics (length,
slope, vegetation) to reduce (to a prescribed reduction target like a TMDL) the outflow of
pollutants from a given disturbed area (soil, crop, area, management practices, design storm
return period).
VFSMOD has been tested in a variety of settings (agroforestry, mining and roads) with good
model predictions against measured values of infiltration, outflow, and vegetation trapping
efficiency for sediments, P, and pesticides. Although the model was originally developed as
research tool, is now widely used by consultants, planners and regulators to design optimal filter
strips for specific scenarios or to assess effectiveness of existing VFS.
Link: http://carpena.ifas.ufl.edu/vfsmod/Accessed January 28, 2010
11. Integrated Farm System Model (IFSM)—USDA-ARS
The Integrated Farm System Model (IFSM) is a process-based simulation of dairy, beef, and
crop farming systems. This farm model provides a tool for evaluating the long-term
performance, economics, and environmental impacts of production systems over many years of
weather. Environmental impacts include volatile N losses, NO3 loss to groundwater,
erosion, soluble and sediment P losses to surface water, and greenhouse gas emissions.
2-230 Chapter 2. Agriculture
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
Link: http://www.ars.usda.gov/Main/docs.htm?docid=8519 Accessed January 27, 2010
12. Dairy Greenhouse Gas Model (DairyGHG)—USDA-ARS
The Dairy Greenhouse Gas Model (DairyGHG) is an easy to use software tool that estimates
total greenhouse gas emissions and the carbon footprint of a dairy production system.
DairyGHG uses a relatively simple process-based model to predict the primary GHG emissions
from the production system, which include the net emission of carbon dioxide plus all emissions
of methane and nitrous oxide. Emissions are predicted through a daily simulation of feed use
and manure handling where daily values of each gas are summed to obtain annual values. A
carbon footprint is then calculated as the sum of both primary and secondary emissions in CO2
equivalent units divided by the milk produced. Secondary emissions are those occurring during
the production of resources used including machinery, fuel, electricity, fertilizer, pesticides, and
plastic. DairyGHG is available for download from our Internet site
(http://ars.usda.gov/naa/pswmru). The model includes a fully integrated help system with a
reference manual that documents the relationships used to predict emissions.
Link: http://www.ars.usda.gov/Main/docs.htm?docid=17355 Accessed January 27, 2010
13. Cropware—Cornell University Extension
Cropware is used to develop plans in accordance with the NRCS Nutrient Management
Standard (Standard 590), making the output of Cropware a key component of Comprehensive
Nutrient Management Plans. Cornell Cropware integrates the following tools for effective
nutrient management planning:
• Cornell crop nutrient guidelines for a full range of agronomic and vegetable crops.
• Nutrient credits from many sources, including manure, soil, sod, and fertilizer.
• Equations for the conversion of soil test values from other laboratories into Cornell
Morgan equivalents.
• Environmental risk indices, including the New York State Phosphorus Runoff Index and
the Nitrate Leaching Index.
• On-farm logistics, such as manure production, storage, and inventories Report
generation for guiding on-farm implementation.
Link: http://nmsp.cals.cornell.edu/software/cropware.html Accessed January 27, 2010
Chapter 2. Agriculture 2-231
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
14. Soil Test Conversion Tools—Cornell University Extension
This program converts soil test results from Brookside Laboratories Inc. (Mehlich 3 P, K, Ca,
Mg), Spectrum Analytic Inc. (Mehlich 3 P, K, Ca, and Mg and Morgan P, K, Ca, and Mg), A&L
Laboratories Inc. (Mehlich 3 P, K, Ca, Mg and Modified Morgan P), and the soil testing
laboratories from the University of New Hampshire (Mehlich 3 P, K, Ca and Mg), University of
Massachusetts (Morgan P, K, Ca, and Mg) and the Universities of Vermont and Maine (Modified
Morgan P, K, Ca, Mg) to Cornell University Morgan Equivalents. P conversions from Mehlich 3
data require measured values for soil pH, Mehlich 3 P, Ca, and Al. For each test, the range of
valid input data is given by a minimum value (min) and a maximum value (max). Also given are
the correlation coefficients (r2) for each of the conversion models. Conversions with larger r2
values are more reliable. Models were derived using New York soils. There is uncertainty
involved with each of the conversions and we now know there is seasonality in the conversions
with the most reliable conversions obtained when samples are taken after harvest and before
manure application. The user assumes all risk and it is recommended to submit samples for the
Cornell Morgan test to check on the accuracy of the conversion models for your farm or the farm
you work with. It is also recommended to take three subsamples per acre if you use conversion
models to derive Cornell Morgan soil test equivalents.
Link: http://nmsp.cals.cornell.edu/software/conv-tools.html Accessed January 27, 2010
15. Great Plains Framework for Agricultural Resource Management (GPFARM)—
USDA-ARS
Great Plains Framework for Agricultural Resource Management (GPFARM) is a simulation
model computer application that incorporates state-of-the-art knowledge of agronomy, animal
science, economics, weed science, and risk management into a user-friendly, decision-support
tool. Producers and others can use GPFARM to test alternative management strategies with
regard to sustainability, pollution reduction, and economic return.
Link: http://www.ars.usda.gov/services/software/download.htm?softwareid=234 Accessed
January 27, 2010
16. Soil - Plant - Atmosphere—Water Field & Pond Hydrology (SPAW)—USDA-ARS
SPAW is a daily hydrologic budget model for agricultural fields and ponds (wetlands, lagoons,
ponds and reservoirs). Included are irrigation scheduling and soil N. Companion models for soil
water characteristics and chemical budgets are included. Data input and results are graphical
screens.
Link: http://hydrolab.arsusda.gov/SPAW/lndex.htmAccessed January 28, 2010
2-232 Chapter 2. Agriculture
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
II. Calculators, Spreadsheets, and Graphical Tools
17. Dairy Cattle N Excretion Calculator—Cornell University Extension
The Dairy Cattle N Excretion Calculator enables users to quickly characterize rations, individual
dairy cattle, and groups of dairy cattle to predict the N partitioned to growth, milk production,
pregnancy, urine, and feces. From there, N use efficiency and N volatilization from the barn floor
are estimated.
Link: http://www.dairvn.cornell.edu/pages/40dairv/420precision/424herdspread.shtml Accessed
January 27, 2010
18. Corn N Calculator—Cornell University Extension
This calculator factors in soil type, drainage, and other factors to estimate corn N requirements.
Link: http://www.dairyn.cornell.edu/pages/20cropsoil/240guides/245corn.shtml Accessed
January 27, 2010
19. Total N Available from Manure Applications—Cornell University Extension
N from urine (ammonium N) is quickly available for crop uptake, while N from feces (organic N)
is more slowly released. Manure represents a mix of both urine and feces, so estimations of the
amount of plant available N from manure should be based on both.
The total manure N calculator uses factors such as animal type, percent dry matter, organic N
content, and application rate to estimate the combined contributions of organic N and
ammonium N to the total pool of plant available N from manure.
Link: http://www.dairyn.cornell.edu/pages/20cropsoil/250credits/256totalN.shtml Accessed
January 27, 2010
20. Other Calculators—Cornell University Extension
This page provides links to calculators for corn N needs, manure nutrients, N credits from
plowed sods, and whole-farm nutrient balancing.
Link: http://nmsp.cals.cornell.edu/software/calculators.html Accessed January 27, 2010
Chapter 2. Agriculture 2-233
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
21. Nutrient Management Spreadsheets—University of Delaware Cooperative Extension
This page includes links to two spreadsheets, one for estimating animal waste quantity, and the
other for estimating poultry litter quantity.
Link: http://ag.udel.edu/extension/NutriManage/spreadsheets.htm Accessed January 27, 2010
22. Crop Nutrient Tool—USDA-NRCS
This is a tool for calculating the approximate amount of N, P, and potassium that is removed by
the harvest of agricultural crops.
Link: http://plants.usda.gov/npk/main Accessed January 22, 2010
23. Crop Fertilizer Recommendation Calculator—Purdue University
This calculator is currently supported for DE, MD, and PA.
Link: http://www.agry.purdue.edu/mmp/webcalc/fertRec.aspAccessed January 22, 2010
24. Manure Nutrient Availability Calculator—Purdue University
This calculator is currently supported for DE, MD, and PA.
Link: http://www.agrv.purdue.edu/mmp/webcalc/nutAvail.aspAccessed January 22, 2010
25. Conservation Buffers—USDA National Agroforestry Center
At any given site, the level of pollutant removal from surface runoff depends primarily on buffer
width. The graph and tables at this site can be used to estimate a buffer width that will achieve a
desired level of pollutant removal. The tool is designed to quickly generate estimates of design
width for a broad range of site conditions. Adjustments are made for land slope, soil texture,
field size, and soil surface condition. The tool can be used for sediment, sediment-bound
pollutants, and dissolved pollutants. The tool was developed for agricultural runoff using
VSFMOD (Vegetative Filter Strip Model), but can be applied in a more general way to other land
uses as well.
Link: http://www.unl.edU/nac/bufferguidelines/guidelines/1 water gualitv/19.html Accessed
January 26, 2010
2-234 Chapter 2. Agriculture
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
26. Farm*A*Syst—University of Wisconsin Extension
Farm*A*Syst is a partnership between government agencies and private business that enables
landowners to prevent pollution on farms, ranches, and in homes using confidential
environmental assessments. A system of step-by-step factsheets and worksheets helps
landowners identify the behaviors and practices that create risks associated with livestock waste
storage, nutrient management, wells, hazardous wastes, and petroleum products.
Link: http://www.uwex.edu/farmasyst/ Accessed January 27, 2010
27. Virginia Phosphorus Index—Virginia Tech
The Virginia Phosphorus Index (P-lndex) is a field-level assessment tool that integrates soil,
management, environmental, and hydrologic (transport) characteristics to estimate the relative
risk of phosphorus (P) losses through erosion, surface runoff and subsurface transport to water
bodies.
Link: http://p-index.agecon.vt.edu/Accessed April 22, 2010
III. Compilations of Tools
28. Technical Resources Main Page—USDA-NRCS
This page serves as the gateway to a wide range of technical resources provided by USDA.
Link: http://www.nrcs.usda.gov/technical/
29. Animal Feeding Operations (AFO) Virtual Information Center—EPA
The AFO Virtual Information Center is a tool to facilitate quick access to livestock agricultural
information in the US. This site is a single point of reference to obtain links to state regulations,
Web sites, permits and policies, nutrient management information, livestock and trade
associations, federal Web sites, best management practices and controls, cooperative
extension and land grant universities, research, funding, and information on environmental
issues. The nutrient management information page has links to nutrient management resources
for Delaware, Maryland, Pennsylvania, Virginia, and West Virginia.
Link: http://cfpub.epa.gov/npdes/afo/virtualcenter.cfm Accessed January 28, 2010
Chapter 2. Agriculture 2-235
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
30. Software Products—USDA-ARS
This page provides updated information on software tools available from USDA-ARS. Additional
information on ARS models and projects can be found here.
Link: http://www.ars.usda.gov/Services/software/software.htm Accessed January 27, 2010
31. Nutrient Management Planning Software and Support—Univ. of Missouri Extension
This page provides links to national resources that facilitate writing a nutrient management plan.
The listed resources contribute to a unified system for writing a nutrient management plan that
meets national standards for NRCS and EPA.
a. Nutrient Management Data Download: Use the Nutrient Management Data Finder to
obtain data needed by nutrient management software to complete a plan.
b. Spatial Nutrient Management Planner (SNMP): Use the SNMP to collect and analyze
spatial information and create maps needed for completing a nutrient management plan.
c. Purdue's Manure Management Planner (MMP): Use MMP to determine fertilizer and
manure application rates and generate the nutrient management plan.
d. Manure Management Planner (MMP) Tutorials: Tutorials on how to use MMP to develop
a swine, poultry or fertilizer only plan.
e. National Setbacks Database: Access a database on the Web that reports setback
requirements for the 34 states supported by SNMP and MMP.
Link: http://www.nmplanner.missouri.edu/software/Accessed January 22, 2010
IV. Guidance and Other Technical Resources
32. Nutrient and Pest Management Tools and Information— USDA-NRCS
Users will find fact sheets on practices and links to various tools for nutrient and pest
management at this site.
Link: http://www.nrcs.usda.gov/technical/nutrient.html Accessed January 26, 2010
2-236 Chapter 2. Agriculture
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
33. Conservation Practices—USDA-NRCS
At this site users will find links to the Field Office Technical Guide and the National Handbook of
Conservation Practices. Links to each state's electronic Field Office Technical Guide (eFOTG)
can be found here.
Link: http://www.nrcs.usda.gov/technical/standards/Accessed January 26, 2010
34. Agronomy and Erosion—USDA-NRCS
This site has links to the National Agronomy Manual, a publication on using RUSLE2 to design
and predict the effectiveness of vegetative filter strips for sediment control, Core 4
Conservation, and other resources.
http://www.nrcs.usda.gov/technical/agronomy.html Accessed January 27, 2010
35. Animal Feeding Operations—USDA-NRCS
This page provides information on CNMPs and links to the MMP and the CNMP field handbook.
Link: http://www.nrcs.usda.gov/technical/afo/index.html Accessed January 27, 2010
36. Nutrient Management Technical Notes—USDA-NRCS
This page includes links to several fact sheets on diet and feed management for various types
of livestock. The page also includes links for National Conservation Practice Standards for
nutrient management (NRCS Practice Code 590) and waste utilization (NRCS Practice Code
633).
Link: http://www.nrcs.usda.gov/technical/ECS/nutrient/documents.html Accessed January 22,
2010
37. National Range and Pasture Handbook—USDA-NRCS
This handbook includes chapters on grazing management and conservation planning for
grazing lands.
Link: http://www.glti.nrcs.usda.gov/technical/publications/nrph.html Accessed January 27, 2010
Chapter 2. Agriculture 2-237
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
38. Phosphorus Index—USDA-NRCS
This page provides background on the Phosphorus Index, which is intended to provide field
staffs, watershed planners, and land users with a tool to assess the various landforms and
management practices for potential risk of P movement to water bodies.
USDA is careful to point out that
a. the phosphorus index is not intended to be an evaluation scale for determining whether
land users are abiding within water quality or nutrient management standards that have
been established by local, state, or federal agencies. Any attempt to use this index as a
regulatory scale would be grossly beyond the intent of the assessment tool and the
concept and philosophy of the working group that developed it. The Phosphorus Index is
proposed to be adapted to local conditions by a process of regional adaptations of the
site characteristic parameters. This local development process must involve those local
and state agencies and resource groups that are concerned with the management of
phosphorus. After the index is adapted to a locality, it must be tested by the
development group to assure that the assessments are giving valid and reasonable
results for that region. Field testing of the index is one of the most appropriate methods
for assessing the value of the index.
Link: http://www.nrcs.usda.gov/technical/ecs/nutrient/pindex.html Accessed January 29, 2010
39. SERA-17 Publications and BMP Fact Sheets
SERA-17 is an organization of research scientists, policy makers, extension personnel, and
educators whose mission is to develop and promote innovative solutions to minimize
phosphorus losses from agriculture by supporting
• Information exchange between research, extension, and regulatory communities
• Recommendations for phosphorus management and research
• Initiatives that address phosphorus loss in agriculture
Link: http://www.sera17.ext.vt.edu/SERA 17 Publications.htm Accessed January 22, 2010
40. Managing Cover Crops Profitably, 3rd Edition—SARE
This 2007 update from Sustainable Agriculture Research and Education (SARE) includes
information on the benefits of cover crops, selecting cover crops, the use of cover crops with
conservation tillage, crop rotations, and a wide range of legume and non-legume cover crops.
Appendix E contains contact information for regional cover crop experts
2-238 Chapter 2. Agriculture
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
Link: http://www.sare.org/publications/covercrops/index.shtml Accessed January 27, 2010
41. Precision Feed Management Certification for Dairy Professionals—Mid-Atlantic Water
Program
To help reduce nutrient pollution and implement the NRCS Feed Management Standard 592,
specialists in Pennsylvania, Maryland and Virginia are working with NRCS and the American
Registry of Professional Animal Scientists to develop a process to certify nutritionists as feed
management planners. With few areas in the nation working with the dairy industry and NRCS
on feed management, the Mid-Atlantic is being looked at as a potential standard for how other
states can train nutritionists for a feed management certification and meet their post-
certification, professional needs. This page provides current information on precision feed
management certification, including contact information for leaders from MD, PA, and VA.
Link: http://mawaterquality.org/industrv change/precision feed mgmt.html Accessed January
27,2010
42. Mid-Atlantic Better Composting School—Mid-Atlantic Water Program
Because commercial compost can be manufactured from a variety of waste materials, a variety
of standards have been established based on end-uses. Managers of composting facilities
should be familiar with these standards and with the waste materials and composting systems
that can best produce the desired products. Composting to produce a product that is consistent
in quality will require good management and quality control.
By enrolling in the Mid-Atlantic Better Composing School, participants will not only learn the
basics of making good compost, but they will also have the opportunity to tour commercial
operations, perform product sampling and learn simple procedures for compost testing.
Link: http://mawaterquality.org/industrv change/ma composting school.html Accessed January
27,2010
43. Environmental Management System for Manure—Mid-Atlantic Water Program
Members from the Mid-Atlantic Water Program (MAWP) are collaborating with CLEANeast to
assess livestock and poultry operations in sensitive watersheds across PA, MD, and VA using
an Environmental Management Systems (EMS) model. An EMS is a voluntary, flexible business
management system that helps farmers and managers to develop their own strategies for
integrating environmental considerations into the daily operations of a farm.
Chapter 2. Agriculture 2-239
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
By implementing pilot assessments across farms in PA, VA, and MD, team members will
demonstrate how an EMS can not only reduce pollution from farms, but also increase operating
efficiency, achieve public acceptance without regulatory oversight, and elicit confidence in
citizens that the wastes are being handled in an environmentally sound manner.
This page also provides state contacts information.
Link: http://mawaterquality.org/industrv change/env mgmt system manure.html Accessed
January 27, 2010
44. Mid-Atlantic Nutrient Management Handbook—Mid-Atlantic Water Program
The Mid-Atlantic Nutrient Management Handbook was written as a reference text for nutrient
management training programs offered by state regulatory agencies. The Handbook was based
off an earlier nutrient management training manual that was widely used in the Chesapeake Bay
watershed, but revised to incorporate advances in soil, crop, and nutrient management research
and the techniques used to protect surface and groundwater.
Link: http://mawaterquality.org/capacitv building/ma nutrient mgmt handbook.html Accessed
January 27, 2010
45. Information on Nutrient and Sediment Best Management Practices—Chesapeake Bay
Program
This report led by the University of Maryland Mid-Atlantic Water Program includes nutrient and
sediment reduction effectiveness estimates of select agricultural, stormwater and forestry best
management practices (BMPs). With funding from the Chesapeake Bay Program Office, the
Mid-Atlantic Water Program developed definitions and effectiveness estimates for BMPs that
states were implementing or proposing to implement as part of their efforts to meet the nutrient
and sediment reduction goals necessary to restore the Bay. The report provides realistic,
science-based estimates of expected nutrient and sediment reduction performance from these
BMPs and reflects current research and knowledge as well as average operational conditions
representative of the entire Chesapeake Bay Watershed.
Link: http://www.chesapeakebay.net/marylandbmp.aspx?menuitem=34449 Accessed January
27,2010
46. Fact Sheets—University of Delaware Cooperative Extension
This page contains links to several fact sheets on nutrient management, poultry litter
management, and animal waste management.
2-240 Chapter 2. Agriculture
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
Link: http://ag.udel.edu/extension/NutriManage/publications.htm Accessed January 27, 2010
47. Nutrient Management—Maryland Department of L., J. A. Nienaber, et al. (2003).
Performance of a passive feedlot runoff control and treatment system. Transactions of
the ASAE 46(6): 1525-1530.
Ladha, J.K., Pathak, H., Krupnik, T.J., Six, J. and van Kessel, C. 2005. Efficiency of fertilizer
nitrogen in cereal production: retrospects and prospects. /Advances in Agronomy 87:85-
156.
Mosier, A.R., J.K. Syers, and J.R. Freney. 2004. Ch. 1-Nitrogen fertilizer: an essential
component of increased food, feed, and fiber production, pp. 3-15. In A.R. Mosier, J.K.
Syers, and J.R. Freney (eds.). Agriculture and the Nitrogen Cycle. Assessing the impacts
This page provides various links to nutrient management fact sheets, recommendations, and
training opportunities.
Link: http://www.mda.state.md.us/resource conservation/nutrient management/index.php
Accessed January 27, 2010
48. Nutrient Management Program—University of Maryland Extension
The Agricultural Nutrient Management Program is a component of the University of Maryland's
College of Agriculture and Natural Resources Nutrient Management Programs and focuses on
reducing the pollution of the Chesapeake Bay by plant nutrients from cropland. The Program
provides nutrient planning services to Maryland farmers via a network of nutrient management
advisors located in all county Extension offices and provides continuing education and technical
support to certified nutrient management consultants via state and regional nutrient
management specialists.
One of these services is the development of nutrient management plans, which are documents
that incorporate soil test results, yield goals, and estimates of residual N to generate field-by-
field nutrient recommendations.
Link: http://anmp.umd.edu/ Accessed January 27, 2010
49. Nutrient Management Plan Writing Tools—University of Maryland Extension
A nutrient management plan is a formal document that balances crop nutrient needs with
nutrients that are applied in the form of commercial fertilizer, animal manure, or biosolids. The
plan contains soil test results, manure and biosolids analyses (where applicable), yield goals,
Chapter 2. Agriculture 2-241
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
and estimates of residual N to generate field-by-field nutrient recommendations. The following
information sheets and work sheets will help producers in the plan writing process.
Link: http://anmp.umd.edu/Plan/Plan Writing.html Accessed January 27, 2010
50. Phosphorus Site Index—University of Maryland Extension
The Phosphorus Site Index, or PSI, is an integral part of a nutrient management plan. If a
producer intends to add P in commercial or organic forms (including starter fertilizer) to a field
and the soil test indicates a P fertility index value (FIV-P) of 150 or more for that particular field,
then the PSI should be calculated. The PSI takes into consideration P loss potential due to site
and transport characteristics and management and source characteristics.
Link: http://anmp.umd.edu/PSI/PSI.html Accessed January 27, 2010
51. Nutrient Management Software and Publications—University of Maryland Extension
This page provides summary information and links to available publications and software for
nutrient management in Maryland.
Link: http://anmp.umd.edu/Pubs/Pubs.html Accessed January 27, 2010
52. Nutrient Management Spear Program—Cornell University
The vision of the Cornell University's Nutrient Management Spear Program is to assess current
knowledge, identify research and educational needs, conduct applied, field and laboratory-
based research, facilitate technology and knowledge transfer, and aid in the on-farm
implementation of strategies for field crop nutrient management, including timely application of
organic and inorganic nutrient sources to improve profitability and competitiveness of New York
State farms while protecting the environment.
This page has links to a variety of nutrient management resources, including nutrient guidelines,
N management, and the New York State Phosphorus Runoff Index. These links provide
additional links to tools and resources such as Cropware and other nutrient management
calculators.
Link: http://nmsp.cals.cornell.edu/index.html Accessed January 27, 2010
2-242 Chapter 2. Agriculture
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
53. Manure Management—Penn State College of Agricultural Sciences
This page provides information on manure management at animal operations, including links to
information specific to Pennsylvania.
Link: http://www.das.psu.edu/research-extension/nutrient-management/manure Accessed
January 27, 2010
54. Pennsylvania Nutrient Management Program—Penn State University
This Web site provides a comprehensive source of information about Pennsylvania's Nutrient
Management Act (Act 38, 2005) Program, and associated technical guidance and educational
information. It also provides limited information concerning related programs. The Web site has
been developed and is maintained through a workgroup representing various partnering
agencies actively involved with the Pennsylvania Nutrient Management Act Program.
Contributions to this site represent the collective efforts of that workgroup
Link: http://panutrientmgmt.cas.psu.edu/ Accessed January 27, 2010
55. Planning Tools and Resources—Penn State University
This page provides links to the nutrient management plan standard format, a nutrient balance
spreadsheet, the Pennsylvania Phosphorus Index spreadsheet, a pasture nutrient calculator,
and other resources associated with nutrient management in Pennsylvania. Contained within
the Phosphorus Index spreadsheet is contact information for state experts.
Link: http://panutrientmgmt.cas.psu.edu/main planning tools.htm Accessed January 27, 2010
56. Nutrient Management Technical Manual—Penn State University
This is the technical manual for Pennsylvania's Nutrient Management Act Program.
Link: http://panutrientmgmt.cas.psu.edu/main technical manual.htm Accessed January 27,
2010
57. Educational Materials—Penn State University
This page provides links to fact sheets and publications addressing of wide range of topics
associated with nutrient management and manure management in Pennsylvania.
Link: http://panutrientmgmt.cas.psu.edu/em publications.htm Accessed January 27, 2010
Chapter 2. Agriculture 2-243
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
58. Fact Sheets on Agriculture and Environmental Quality—Virginia Tech Extension
The page provides links to fact sheets covering a range of topics including composting, P
management, and livestock exclusion.
Link: http://pubs.ext.vt.edu/category/environmental-qualitv.html Accessed January 27, 2010
59. Virginia Agricultural BMP Cost Share and Tax Credit Programs—Virginia Department
of Conservation and Recreation
This page provides information and links associated with agricultural BMPs in Virginia, including
the Virginia agricultural BMP manual and BMP cost-sharing.
Link: http://www.dcr.virginia.gov/soil and water/costshar.shtml Accessed January 27, 2010
60. Nutrient and Waste Management—West Virginia University Extension Service
This page provides links to nutrient management training courses including the P index,
information on nutrient management consultant certification, manure sampling and analysis
methods, and related Web sites.
Link: http://www.wvu.edu/~agexten/wastmang/index.html Accessed January 28, 2010
61. Comprehensive Livestock Environmental Assessments and Nutrient (CLEANEast)
Management Plan program—RTI International and North Carolina State University
CLEANEast provides confidential, free technical support to farms including beef, dairy, swine, or
poultry operations located in 27 eastern states. It helps farm operators identify and implement
farm management practices that protect the environment. CLEANEast is a voluntary program
that farm operators can apply to for on-site support services from a qualified Technical
Assistance Professional to:
• Conduct an Environmental Assessment
• Update an existing Nutrient Management Plan
• Prepare a new Nutrient Management Plan
Link: https://livestock.rti.org/ Accessed January 28, 2010
62. Comprehensive Nutrient Management Planning (CNMP)—extension
The details of a Comprehensive Nutrient Management Plan (CNMP) are described at this site,
including links to various handbooks and guidance documents important to the development of
2-244 Chapter 2. Agriculture
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
a CNMP for an animal feeding operation. For example, a key objective of a CNMP is to
document the plans of an animal feeding operation owner/operator to manage manure and
organic by-products in combination with conservation practices and facility management
activities to protect or improve water quality. NRCS has listed six elements of a CNMP that
should be considered during preparation of the plan, though a CNMP is not required to contain
all six elements. The components that should be considered are the following:
• Manure and Wastewater Storage and Handling
• Land Treatment Practices
• Nutrient Management
• Record Keeping
• Feed Management
• Other Utilization Activities
A complete description of these elements, and what each element specifically covers, is
included in the USDA-NRCS National Planning Procedures Handbook (Part 600.5). Users
should check with their agriculture and natural resources agencies to see if their state has its
own specific CNMP requirements and guidance.
Link:
http://www.extension.org/pages/Comprehensive Nutrient Management Planning %28CNMP%29
Accessed January 22, 2010
63. CNMP Core Curriculum—Iowa State University
There are several sources for additional information about CNMPs. Many land grant universities
and other commodity/producer organizations provide informational literature and Web sites.
Additionally, state NRCS offices often maintain CNMP/TSP informational Web pages. A source
of information about CNMPs is the CNMP Core Curriculum training modules maintained by Iowa
State University and available through the Midwest Plan Service. The CNMP Core Curriculum is
also a good resource for educators interested in providing training on CNMP development. Also,
the breadth of information covered in the topic areas make the curriculum a good source of
materials for smaller scale trainings, such as shorter, topic specific extension programs. The
CNMP Core Curriculum provides a consistent background and framework from which state or
regionally specific CNMP courses can be developed. There are ten sections in the
Comprehensive Nutrient Management Plan (CNMP) Core Curriculum. The section topics are:
• Introduction to a Comprehensive Nutrient Management Plan
• Conservation Planning
Chapter 2. Agriculture 2-245
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
• Land Treatment Practices
• Manure and Wastewater Storage and Handling
• Nutrient Management
• Feed Management
• Record Keeping
• Air Quality
• Alternative Utilization
• TSP Certification
Link: http://www.abe.iastate.edu/wastemgmt/cnmp-curriculum.html Accessed January 26, 2010
64. Manure Management Planner Tutorials—Univ. of Missouri Extension
These tutorials were part of a training program for Missouri nutrient management planners. The
tutorials outline many of the steps in developing a nutrient management plan in MMP. Many of
the steps in using MMP are universal among all states. These tutorials were developed in 2005
for an earlier version of MMP, but the authors believe that the tutorials are still mostly applicable
to the planning process when using MMP. Separate tutorials were developed for a swine
operation (liquid manure), poultry operation (solid manure) and fertilizer plan (no manure).
Link: http://www.nmplanner.missouri.edu/software/mmp tutorial.asp Accessed January 22,
2010
2-246 Chapter 2. Agriculture
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
Chapter 3.
Urban and Suburban
Contents
1 Introduction 3-5
1.1 Need for Urban and Suburban Runoff Guidance Update 3-5
1.1.1 Purpose 3-5
1.1.2 Intended Audience 3-12
1.1.3 Water Quality Significance of Urban Runoff in the Chesapeake Bay
Watershed 3-12
1.1.4 Managing Urban Runoff to Reduce Nutrients and Sediment Loss 3-18
1.2 Overview of the Urban Runoff Chapter 3-28
1.2.1 Management Practices and Management Practice Scales 3-29
1.2.2 Implementation Measures for Urban Runoff in the Chesapeake Bay
Watershed to Control Nonpoint Source Nutrient and Sediment Pollution....3-31
2 Implementation Measures for Reducing Urban Runoff Volume 3-38
2.1 Maximize Infiltration, Evapotranspiration, and Harvest and Use 3-41
2.2 Implement Policies to Preserve and Restore Predevelopment Hydrology 3-42
2.3 Land Use Planning and Development Techniques to Direct Development 3-47
2.3.1 Impacts of Land Use on Hydrology and Geomorphology 3-47
2.3.2 Appropriate Designs as Part of a Comprehensive Watershed Plan 3-49
2.3.3 New Development and Redevelopment Strategies to Minimize Impacts
of Development 3-53
2.4 Use Conservation Design and LID Techniques 3-57
2.5 Evaluate Planning Manuals and Guides 3-60
2.6 Evaluate Transportation-Related Standards 3-62
2.7 Minimize Directly Connected Impervious Areas in New Development,
Redevelopment, and Retrofit 3-66
2.8 Implement Restoration 3-67
2.8.1 Native Landscapes and Urban Tree Canopy 3-67
Chapter 3. Urban and Suburban 3-1
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
2.8.2 Streams, Floodways, and Riparian Areas 3-69
2.9 Reduce Impacts of Existing Urban Areas 3-72
2.9.1 Retrofits 3-72
2.9.2 Redevelopment 3-74
2.10 Costs of Green Infrastructure/LID Practices 3-75
2.10.1 Key factors in evaluating costs of Green Infrastructure/LID 3-76
2.10.2 Types of Cost Analysis that Can Support Decision Making 3-82
2.10.3 Costs of Individual Practices 3-93
3 Implementation Measures for Reducing Pollutant Concentrations with Source Controls
and Treatment 3-103
3.1 Source Control/Pollution Prevention 3-105
3.1.1 Identify Pollutants of Concern 3-105
3.1.2 Implement Pollution-Prevention and Source-Reduction Policies 3-112
3.1.3 Implement Source Control Practices 3-114
3.1.4 Public Outreach 3-117
3.1.5 Disconnecting Directly Connected Impervious Areas, Such as
Downspout Disconnection 3-119
3.1.6 Inspections of Commercial/Industrial Facilities 3-119
3.2 Runoff Treatment 3-121
3.2.1 Identify Pollutants of Concern 3-121
3.2.2 Select Treatment Practices Appropriate to the POC 3-121
4 Urban Runoff Management for the Redevelopment Sector 3-131
4.1 Establish Stormwater Performance Standards for the Redevelopment Sector
Consistent with the Goal of Restoring Predevelopment Hydrology 3-136
4.2 Stormwater Management Practices for Redevelopment 3-136
4.2.1 Practice Integration and Assessment Tools 3-140
4.3 Site Evaluations 3-142
4.4 Planning Documents and Specification Review 3-142
4.5 Demonstration Projects 3-143
4.6 Incentives for Early Adopters 3-143
4.7 Maximize Urban Forest Canopy 3-143
4.8 Amend Compacted Urban Soils 3-143
5 Turf Management 3-144
5.1 Background 3-147
3-2 Chapter 3. Urban and Suburban
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
5.2 Turf-Related Impacts 3-152
5.2.1 Fertilizer Applications 3-152
5.2.2 Irrigation 3-153
5.2.3 Energy and Air Quality 3-153
5.3 Turf Management Strategies, Practices, Resources and Examples 3-154
5.3.1 Turf Landscape Planning and Design 3-154
5.3.2 General Turfgrass Best Cultural Practices 3-155
5.3.3 Fertilizer Management 3-157
5.3.4 Pesticide Management 3-162
5.3.5 Mowing 3-163
5.3.6 Soil Amendments 3-164
5.3.7 Water Management 3-167
5.3.8 Grass Species Selection 3-169
5.3.9 Turf Assessments 3-171
5.3.10 Turf Restrictions 3-176
5.3.11 Incentives for Landscape Conversion 3-176
5.3.12 Environmentally Friendly Landscape Requirements 3-178
5.3.13 Xeriscaping Requirements 3-179
6 References 3-181
Appendix 1: BMP Fact Sheets 3-209
1.1 Introduction 3-209
1.1.1 Performance Estimate Summaries for Infiltration Practices 3-210
1.2 Rainwater Harvesting 3-214
1.3 Green Roofs 3-220
1.4 Blue Roofs 3-226
1.5 Bioretention/Biofiltration 3-231
1.6 Infiltration 3-246
1.7 Soil Restoration 3-252
1.8 Reforestation and Urban Forestry 3-258
1.9 Street Sweeping 3-267
1.10 Constructed Wetlands 3-272
Appendix 2: Methods and Tools for Controlling Stormwater Runoff (Quantity and Quality) ..3-281
2.1 Methods and Manuals 3-281
Chapter 3. Urban and Suburban 3-3
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
2.2 Complex, LID-capable Models 3-283
2.3 Simpler Models 3-287
Appendix 3: Procedures and Case Studies from the Section 438 Guidance 3-291
3-4 Chapter 3. Urban and Suburban
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
1 Introduction
1.1 Need for Urban and Suburban Runoff Guidance
Update
1.1.1 Purpose
This chapter was developed to provide guidance on the most up-to-date, proven, and cost-
effective practices for controlling urban and suburban runoff for federal land management in the
Chesapeake Bay region, as required by Executive Order 13508. Federal agencies in the
Chesapeake Bay watershed will find this guidance useful in managing urban runoff from the
development and redevelopment of federal facilities and other land areas owned or managed by
the federal government.
At the same time, EPA recognizes that the great majority of land in the Chesapeake Bay
watershed is nonfederal land and is managed by private landowners, states, and local
governments. Indeed, the vast majority of actions to restore the Chesapeake Bay will need to
take place on nonfederal lands and will need to be implemented by nonfederal actors. From the
perspective of land management and water quality restoration/protection, the same set of
"proven cost-effective tools and practices that reduce water pollution" are appropriate for both
federal and nonfederal land managers to restore and protect the Chesapeake Bay.
Therefore, states and others (e.g., states, local governments, conservation districts, watershed
groups, developers, and other citizens in the Chesapeake Bay watershed) could choose to use
this guidance document to the extent that they find it relevant and useful to their needs. The
document presents practices and actions that are not unique to federal lands and thus will often
be applicable to lands that are managed by nonfederal land managers. Thus, while this
document has been written specifically to address the needs of federal land managers, other
parties might also find it a useful guide to implementing the most effective and cost-effective
practices available to restore and protect the Chesapeake Bay.
In addition, many of the nutrient and sediment sources in the Chesapeake Bay watershed are
similar to sources in other watersheds around the country. Many of the practices needed to
protect and restore the Chesapeake Bay are the same as or very similar to those used in other
watersheds. Indeed, while great efforts have been made in preparing this document to assure
the consideration of all relevant data for the Chesapeake Bay watershed, has been considered
and used as appropriate in preparing and publishing this guidance, EPA has also employed
data from outside the Chesapeake Bay watershed when it was deemed to be relevant and
Chapter 3. Urban and Suburban 3-5
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
applicable to the Chesapeake Bay. For that reason, much of the information provided in this
chapter is relevant to other areas of the United States. Therefore, practitioners outside the
watershed might wish to consider this chapter as they develop and implement their own
watershed plans and strategies to address nutrient and sediment pollution from nonpoint
sources.
The primary approaches recommended in this chapter to protect the Chesapeake Bay and its
tributaries—as well as waters in much of the rest of the United States—from the effects of
development are to use green infrastructure/low impact development (LID) approaches and
planning and development techniques, such as smart growth, that minimize the detrimental
effects of development on the environment. Section 2 of this chapter focuses on such
approaches.
The objective of green infrastructure/LID is to maintain or restore the predevelopment site
hydrology in regard to the temperature, rate, volume, and duration of runoff flow. That can be
accomplished during development, redevelopment, or retrofit. In some cases, achieving more
runoff retention might be necessary for water quality protection, and this document does not
preclude setting that performance objective. More specifically, this approach is intended to
maintain or restore stream flows such that receiving waters, and stream channels, are not
negatively affected by changes in runoff. That approach protects predevelopment hydrology and
provides significant reductions in pollutant runoff. However, in some circumstances, specific
additional pollutant control practices, (e.g., source controls) will need to be implemented to
address pollutant runoff, and Section 3 of this chapter addresses those practices.
Planning can help guide development to areas that minimize effects on sensitive resources and
natural areas. Planning can help ensure that new and redevelopment sites are designed to
reduce runoff volume through on-site stormwater retention.
This chapter
• Emphasizes replicating predevelopment hydrology with respect to runoff volume,
temperature, rate, and duration as a more reliable and effective stormwater
management practice than traditional approaches that focus on pollutants without
addressing hydrology. That emphasis is already expressed in a number of recent EPA
documents and numerous states, cities, and expert groups, including the National
Academy of Sciences (http://epa.gov/greeninfrastructure).
• Incorporates by reference the Technical Guidance on Implementing the Stormwater
Runoff Requirements for Federal Projects under Section 438 of the Energy
Independence and Security Act, EPA 841-B-09-001 (USEPA 2009e), which provides the
hydrologic analysis for this approach. Elements of that document are referenced here,
3-6 Chapter 3. Urban and Suburban
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
but it is not repeated in its entirety; it is provided at
http://www.epa.gov/owow/nps/lid/section438/.
• Builds on that technical guidance by providing users with sources to the newest research
on key management practices and approaches and refers the reader to other resources
where appropriate.
• Emphasizes those practices that can have multiple associated benefits, including cost-
effectiveness and energy-savings. Some of those practices, in fact, cost less than the
conventional stormwater management alternative in addition to providing other
environmental and societal benefits.
• This document addresses technical management practices for restoring and maintaining
surface water quality. Green infrastructure/LID is generally used for managing smaller
storm events that compose the bulk of annual rainfall and therefore contributes the most
to both pollutant loading and stream degradation. This document does not address other
stormwater issues, primarily flood-control or stormwater program management.
However, those issues are addressed at length in documents referenced here.
Such an approach of maintaining predevelopment hydrology is already required for federal
facilities by the Energy Independence and Security Act (EISA) of 2007 (P.L 110-140, H.R. 6)
section 438. Subsequent EPA guidance (EPA 841-B-09-001) (USEPA 2009e) provides advice
on how to implement it at federal facilities.
EISA mandates certain federal facilities to comply with the following:
Stormwater runoff requirements for federal development projects. The sponsor of
any development or redevelopment project involving a Federal facility with a footprint that
exceeds 5,000 square feet shall use site planning, design, construction, and maintenance
strategies for the property to maintain or restore, to the maximum extent technically
feasible, the predevelopment hydrology of the property with regard to the temperature,
rate, volume, and duration of flow.
State and local stormwater programs established under the Clean Water Act Amendments of
1987 were traditionally established to control pollutants that are associated with municipal and
industrial discharges, e.g., nutrients, sediment, and metals. Increases in runoff volume and peak
discharge rates have been regulated through state and local flood control programs but in many
states have not been significantly addressed with regard to their role in water quality and habitat
protection. Knowledge accumulated during the past 20 years has led to the conclusion that
conventional approaches to control runoff have not resulted in adequate protection of the
nation's water resources, and, in fact, have had detrimental effects associated with increased
volumes of runoff (National Research Council 2008).
Chapter 3. Urban and Suburban 3-7
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
An example of that detrimental effect is referenced in Figure 3-1.
This chapter emphasizes site-specific management practices from green infrastructure/LID that
are driven by locally applicable performance objectives. Each site or watershed has its own
unique circumstances—a combination of land uses, water resource needs, environmental
conditions, regulatory drivers, and community attributes—that will affect which approaches are
the most successful in terms of effectiveness and community acceptance. The means selected
will vary depending on the development setting and site-specific opportunities and constraints;
however, designing to replicate predevelopment hydrology is the overall goal that best ensures
achieving full designated uses of the waters. In cases where green infrastructure/LID is not
feasible on-site or is otherwise inadequate to meet water quality objectives, additional measures
should be considered, as discussed in Section 3 of this chapter.
The past decade has brought significant growth in the use of approaches that seek to control
runoff volume at the site scale using a variety of decentralized stormwater controls and runoff
retention methods that have the objective of replicating the predevelopment hydrology as much
as technically feasible. That type of holistic, hydrology-based approach to urban runoff
management is termed low impact development or LID (also referred to variously as better site
design, environmentally sensitive design, sustainable stormwater management, and green
infrastructure, among others). The approach has been proven to be technically achievable and
cost-effective; examples demonstrating this are provided in Figures 3-2 and 3-3 that describe
projects in Portland, Oregon, and in coastal North Carolina.
The purpose of this chapter is to present an overview of the practices and resources available
for federal facilities and others to achieve water quality goals in the most cost-effective and
potentially successful manner, with the overall objective of improving water quality, habitat, and
the environmental and economic resources of the Chesapeake Bay and its tributaries.
3-8 Chapter 3. Urban and Suburban
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
A Maryland Department of Natural Resources (DNR) study highlights the detrimental impact that
development, loss of forest, and temperature changes have had on brook trout, Maryland's only native trout
species, based on three decades of study.
For every one percent increase in impervious land cover in a stream's watershed, the odds of brook trout
survival decreased by nearly 60 percent (Stranko, et.al. 2008).
Legend
|H '""act (3)
Reduced (5)
^H Greatly Reduced (42)
^_ Extirpated (83)
| 1 Unknown, No Data (12)
| 1 Never Occulted (46)
- — Interstate
: Cities
Map data derived from state and federal data and compiled in EBTJV assessment results titled, Distribution,
status, and perturbations to brook trout within the eastern United States, 2006. Authored by Mark Hudy,
US Forest Service; Teresa Thieling, James Madison University; Nathaniel Gillespie, Trout Unlimited; Eric
Smith, Virginia Tech. Map created on 2/24/06 by Nathaniel Gillespie, Source: Eastern Brook Trout: Status
and Threats, Maryland, Trout Unlimited, brochure. www.tu.org/atf/cf/%7BED0023C4-EA23-4396-9371-
8509DC5B4953%7D/brookie MD.pdf. Eastern Brook Joint Trout Venture.
Figure 3-1. Maryland Department of Natural Resources study (2008) and Trout Unlimited mapping
(2006) document the extensive loss of brook trout from development impacts.
Chapter 3. Urban and Suburban
3-9
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
Portland Bureau of Environmental Services (BES) Tabor to the River project integrates hundreds of sewer,
green stormwater management, tree planting and other watershed projects to improve sewer system
reliability, stop sewer backups in basements and street flooding, control combined sewer overflows (CSOs)
to the Willamette River, and restore watershed health.
The 1,472-acre basin is high-density residential development, with commercial land use, and
approximately 37% impervious. The Tabor to the River project will address stormwater management and
watershed health by
• Adding 500 LID facilities in the public right-of-way (curb extensions, vegetated planters, and flow
restrictors)
• Addressing Runoff from 8 acres of parking and rooftops on private property controlled by LID facilities
(e.g., vegetated planters, rain gardens, eco-roofs)
• Planting two revegetation projects to remove invasive species
• Planting 3,500 trees in the city's right-of-way
• Conducting Neighborhood education and project outreach
• Improving access to the Willamette River from an adjacent neighborhood
Sources:
Portland BES Web site for Tabor to the River: http://www.portlandonline.com/bes/index.cfm?c=47591
Tsurumi, Naomi and Bill Owen Painting it Green—Replacing an All-Pipe Solution with an Integrated Solution
Emphasizing Low Impact Development; American Society of Civil Engineers (ASCE), Low Impact Development
Conference Proceedings, 2008.
Figure 3-2. LID Green Streets save Portland, Oregon, nearly $60 million while restoring water
quality.
3-10 Chapter 3. Urban and Suburban
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
Using LID on a development project in Middlesound, North Carolina, where LID is encouraged to protect
shellfish beds and coastal recreational waters, the developer saved money and realized marketing
advantages compared to tradition stormwater design:
• Gained 3 to 4 additional lots (from 56 to 59)
• Reduced stormwater pipe by 89%
• Decreased road widths 9%
• Eliminated 9,000-ft curb and gutter
• Eliminated 5 infiltration basins
• Eliminated 5 monitoring wells
• Eliminated 10,000 linear feet of stormwater force main
• Saved $1.5 million in fill material
• Increased localized stormwater infiltration
• Eliminated 3 stormwater pumps
• Increased functional and recreation open space
• Minimized wetlands intrusion and wildlife impacts
• Buyers prefer green real estate
• Promotes good neighbor
• Decreased construction traffic
"Your ideas and preliminary plans for incorporating LID for Ridgefield are proving invaluable. After having it
approved for a conventional stormwater system, we were concerned with the extreme costs of the system
and development's financial feasibility. However, with the utilization of an LID stormwater system we can
dramatically reduce the costs and make the project viable again. In our estimates we are projecting a
savings up to $1.5 million and adding 4 lots. In addition, we will be saving many of the natural features and
topography resulting in a 'greener,' more conservation oriented neighborhood."
—Ridgefield Property Developer, February 2009
Source:
Todd Miller, North Carolina Coastal Federation; Heather Burkert, and H.K Burkert & Co.
Figure 3-3. Developer realizes savings and marketing value with LID while better protecting
coastal waters.
Chapter 3. Urban and Suburban 3-11
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
1.1.2 Intended Audience
The primary audience for this chapter is stormwater managers in federal agencies and at the
local, state, and federal levels who are responsible for meeting water quality goals and
implementing water quality programs in developing and developed areas.
Others who can benefit from the information in this chapter include the development community
and its multidiscipline designers, because new and redevelopment projects offer the best
opportunity to implement stormwater controls to mitigate development's effects on water
resources; local public officials responsible for land use and water quality decision making,
academia and research groups, environmental and community organizations, and the business
community.
1.1.3 Water Quality Significance of Urban Runoff in the Chesapeake
Bay Watershed
Urban stormwater runoff is responsible for a significant portion of the nitrogen (N), phosphorus
(P), and sediment loading to the Chesapeake Bay. The loading has been continuing to increase
over time because of development. Understanding the core cause of this problem is essential to
reducing this source.
This section contains background information on the causes and consequences of stormwater
discharges, i.e. the alterations to natural hydrology and the resulting impacts, and solutions that
can be used to address the causes and consequences of stormwater discharges, and how to
implement those solutions such that they will be applicable to all areas of the country and
comply with section 438 of EISA.
Under natural, undisturbed conditions in the mid-Atlantic region, most rainfall is intercepted by
vegetation, infiltrates into the soil where it feeds streams and aquifers, or is returned to the
atmosphere via evapotranspiration. Very little rainfall becomes stormwater runoff, and runoff
generally occurs only with larger precipitation events. Traditional development practices cover
large areas of the ground with impervious surfaces such as roads, parking lots, driveways,
sidewalks, and buildings. Once such development occurs, rainwater cannot infiltrate into the
ground and as a result, runs off the site at rates and volumes that are much higher than would
naturally occur. Underdeveloped conditions, runoff occurs even during small precipitation
events that would normally be absorbed by the soil and vegetation. The collective force of the
increased runoff scours streambeds, erodes stream banks, and causes large quantities of
sediment and other entrained pollutants to enter the waterbody each time it rains (Shaver et al.
2007; Walsh et al. 2005; Booth testimony 2008). Such change in runoff with urbanization is
illustrated in Figure 3-4. Studies of historical temperature patterns in streams recently
documented increases in temperature in many areas; areas in the Chesapeake Bay region
3-12 Chapter 3. Urban and Suburban
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
where statistically significant stream temperature increases have occurred include the Potomac
River, the Patuxent River, and the Delaware River near Chester, Pennsylvania (Kauskai 2010;
http://www.chesapeakebay.net/news streamtemps10.aspx?menuitem=50656).
Predevelopment hydrology.
40% evapotranspiration
Post-development hydrology.
30% evapotranspiration
25% shallow
infiltration
Natural Ground Cover
25% deep
infiltration
10% shallow
infiltration
75%-100% Impervious Cover
5% deep
infiltration
Figure 3-4. Predevelopment and post-development hydrology (USDA).
In recognition of those problems, stormwater managers employed extended detention
approaches to mitigate the effects of increased runoff peak runoff rates. However, wet ponds
and similar practices inadequately protect downstream hydrology because of the following
inherent limitations of the conventional practices (National Research Council 2008; Shaver et al.
2007):
• Poor peak control for small, frequently occurring storms
• Negligible volume reduction
• Increased duration of peak flow
Detention storage targets relatively large, infrequent storms, such as the 2- and 10-year/24-hour
storms for peak flow rate control. As a result of that design limitation, flow rates from smaller,
frequently occurring storms typically exceed those that existed on-site before land development
occurred, and those increases in runoff volumes and velocities typically result in flows erosive to
stream channel stability (Shaver et al. 2007). Section 438 of EISA is intended to address the
inadequacies of the historical detention approach to managing stormwater and promote more
sustainable practices that have been selected to maintain or restore predevelopment site
hydrology.
Chapter 3. Urban and Suburban
3-13
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
A 2008 National Research Council report on urban stormwater confirmed the shortcomings of
current stormwater control efforts. Three of the report's findings on stormwater management
approaches are particularly relevant (National Research Council 2008).
• Individual controls on stormwater discharges are inadequate as the sole solution to
stormwater in urban watersheds.
• Stormwater control measures such as product substitution, better site design,
downspout disconnection, conservation of natural areas, and watershed and land-use
planning can dramatically reduce the volume of runoff and pollutant load from new
development.
• Stormwater control measures that harvest, infiltrate, and evapotranspire stormwater are
critical to reducing the volume and pollutant loading of small storms.
The amount of water on Earth today is the same as it was billions of years ago. Water is
continually recycled through the water cycle (or hydrologic cycle), a system that moves rainfall
from the atmosphere to land, through surface and groundwater systems, to the ocean, and back
into the atmosphere. Water changes its form throughout this cycle between solid, liquid, and
gas—and it moves over the Earth's surface, underground, or through the atmosphere.
The hydrologic cycle is a dynamic system of interdependent parts in constant movement.
Altering one part of the cycle affects other parts because the overall water balance must be
maintained. Removing trees and paving land surfaces, for example, reduces the amount of
infiltration and evapotranspiration and increases the amount of runoff. Additional information on
the hydrologic cycle and how it affects the design of stormwater management practices is in
Stormwater Best Management Practice Design Guide (EPA/600/R-04/121, September 2004,
http://www.epa.gov/nrmrl/pubs/600r04121/600r04121.pdf).
The nutrient cycle is also a dynamic, interdependent process. Development affects soil,
groundwater, and surface water and disrupts the balance, ultimately resulting in damaging
environmental conditions such as those present in the Chesapeake Bay. Schematic
representations of the N and P cycles in wetlands are provided in Figures 3-5 and 3-6.
Additional information on nutrient cycling is available in Nutrient Criteria Technical Guidance
Manual, Wetlands (EPA-822-B-08-001, 2008f).
3-14 Chapter 3. Urban and Suburban
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
Atmospheric
Deposition
N2I
N2 N2<-> Nitrogen I
^Inflow Fixation 1 W
'Plant biomass
•
N03
NH3
Litterfall 4
Volatilization
Plant-C >~
£/ - ,. -
X v .
Mineralization
Organic < > NH4 Wafer Co/umn
_•** A Soil - AFRORIC
1^5
i:
A Soil-AEROBIC
N03-
I Denitritication Microbiar
Organic N -4* Biomass N Adsorbed NrV
So//-.4W>5£«Ofl/C
i N2, N2O (g)
Source: USEPA 2008f
Figure 3-5. N cycling in wetlands.
Water Coin inn
Soil-AEROBIC
Atmospheric
Deposition
Adsorbed
IP
[Fe, Al or
Ca-bound
P]
Soil -ANAEROBIC
Source: USEPA 2008f
Figure 3-6. P cycling in wetlands shown dissolved inorganic phosphorus (DIP), dissolved organic
phosphorus (DOP), particulate organic phosphorus (POP).
Chapter 3. Urban and Suburban
3-15
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
Land cover changes that result from site development include increased imperviousness, soil
compaction, loss of vegetation, and loss of natural drainage patterns resulting in increased
runoff volumes and peak runoff rates. The cumulative effects of the land cover changes result in
alterations of the natural hydrology of a site, which disrupts the natural water balance and
changes water flow paths. The consequences of these impacts include the following:
• Increased volume of runoff. With decreased area for infiltration and evapotranspiration
due to development, a greater amount of rainfall is converted to overland runoff which
results in larger stormwater discharges.
• Increased peak flow of runoff. Increased impervious surface area and higher connectivity
of impervious surfaces and stormwater conveyance systems increase the flow rate of
stormwater discharges and increase the energy and velocity of discharges into the
stream channel.
• Increased duration of discharge. Detention systems generate greater flow volumes for
extended periods. Those prolonged, higher discharge rates can undermine the stability
of the stream channel and induce erosion, channel incision and bank cutting.
• Decreased baseflow and increased flash flooding. Changes to baseflow are caused by
alterations to the hydrologic cycle created by land cover changes and increased
imperviousness, which prevents rain from recharging groundwater, where it serves as
baseflow for streams. Such changes increase the flashiness of streams, resulting in
elevated flows during or after storm events, and greatly diminished baseflows in between
storms.
• Increased pollutant loadings. Impervious areas are a collection site for pollutants. When
rainfall occurs, the pollutants are mobilized and transported directly to stormwater
conveyances and receiving streams via the impervious surfaces.
• Increased temperature of runoff. Impervious surfaces absorb and store heat and transfer
it to stormwater runoff. Higher runoff temperatures can have detrimental effects on
receiving streams. Detention basins magnify this problem by trapping and discharging
runoff that is heated by solar radiation (Galli 1991; Schuelerand Helfrich 1988).
• Habitat modifications and stream morphology changes. Increased runoff rate and
volume alter stream morphology. Highly erosive stormwater can wash out in-stream
structures that serve as habitat. Large storms deepen, widen, and straighten channels,
disconnecting streams from their floodplains and destroying meanders that serve to
dissipate hydraulic energy (Walsh, et al. 2005).
The resulting increases in volume, peak flow, and duration are illustrated in the hydrograph in
Figure 3-7, which is a representation of a site's stormwater discharge with respect to time. The
hydrograph illustrates the effects of development on runoff volume and timing of the runoff.
3-16 Chapter 3. Urban and Suburban
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
Individual points on the curve represent the rate of stormwater discharge at a given time. The
graph illustrates that development and corresponding changes in land cover result in greater
discharge rates, greater volumes, and shorter discharge periods. In a natural condition, runoff
rates are slower than those on developed sites, and the discharges occur over a longer period.
The predevelopment peak discharge rate is also much lower than the post-development peak
discharge rate because of attenuation and absorption by soils and vegetation. In the post-
development condition, there is generally a much shorter time before runoff begins because of
increased impervious surface area, a higher degree of connectivity of those areas, and the loss
of soils and vegetative cover that slow or reduce runoff. Simply reducing the peak flow rate, and
extending the duration of the predevelopment peak flow, is not effective because as the different
discharge sources enter a stream, the hydrographs are additive, and the extended
predevelopment peak flows combine to produce an overall higher than natural peak. The result
is the pervasive condition of channel incising, erosion, and loss of natural stream biological and
chemical function as observed in Figure 3-8.
Q
Post-Development Condition
Pre-Development Condition
Note: Q = volumetric flow rate; t = time
Figure 3-7. Post-development hydrograph shows how development results in
increased peak flow, shorter duration, and increased overall volume.
Chapter 3. Urban and Suburban
3-17
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
Figure 3-8. Stream displaying the effects of stormwater runoff and channel downcutting.
1.1.4 Managing Urban Runoff to Reduce Nutrients and Sediment
Loss
1.1.4.1 Preserving and Restoring Hydrology
Green infrastructure practices include a wide variety of practices that use such mechanisms.
They can be used at the site (Figure 3-9), neighborhood, and watershed/regional scales. In this
document, the focus is on site-level practices, such as bioretention and water harvesting, but it
also addresses the land management scales of planning (i.e., planning techniques such as
smart growth), and site design (i.e., site design techniques such as conservation development).
Restoring or maintaining predevelopment hydrology has emerged as a control approach for
several reasons. Most importantly, the approach is intended to directly address the root cause
of impairment. Current control approaches have been selected in an attempt to control the
symptoms (peak flow, and excess pollutants), but the strategy is ineffectual in many cases
because of the scale of the problem, the cumulative effects of multiple developments and the
need to manage both site and watershed level effects. With current approaches, it is also
difficult to adequately protect and improve water quality because the measures employed are
not addressing the root problem, which is a hydrologic imbalance.
3-18
Chapter 3. Urban and Suburban
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
Designing facilities with the goal of maintaining or
restoring predevelopment hydrology provides a site-
specific basis and an objective methodology with
which to determine appropriate practices to protect
the receiving environment.
Using predevelopment hydrology as the guiding
control principle also allows the designer to
consider climatic and geologic variability, and tailor
the solutions to the project location. Thus, the one-
size-fits-all approach is not appropriate because the
design objective is dictated by the predevelopment
site conditions and other technicalities of the project
site and facility use. Site assessments of historical
infiltration and runoff rates will inform the designer
and provide the basis for a suitable design. The use
of this approach will minimize compliance
complications that can arise from prescriptive
design approaches that do not account for the
variability of precipitation frequencies, rainfall
intensities, and land cover and soil conditions that
influence infiltration and runoff.
Figure 3-9. Parking lot bioswale and
permeable pavers in Chicago.
More information on addressing hydromodification and riparian buffers are provided in separate
volumes of this document.
1.1.4.2 Defining Green Infrastructure/LID
LID is a stormwater management strategy that many
localities across the country have adopted. Green
infrastructure is a term also used to describe LID
practices, with the connotation that such practices
can be thought of as infrastructure, just like a pipe or
other structural management practice. Green
infrastructure/LID is a stormwater management
approach and set of practices that can be used to
reduce runoff and pollutant loadings by managing ^^^^^^^^^^^^^^^^^^_
the runoff as close to its source(s) as possible. A set
or system of small-scale practices, linked together on the site, is often used. LID approaches
can be used to reduce the effects of development and redevelopment activities on water
Examples of LID Practices
• Infiltration basins and trenches
• Permeable pavement
• Disconnected downspouts
• Rain gardens and other vegetated
treatment systems
Chapter 3. Urban and Suburban
3-19
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
resources. In the case of new development, LID is typically used to achieve or pursue the goal
of maintaining or closely replicating the predevelopment hydrology of the site. In areas where
development has already occurred, LID can be used as a retrofit practice to reduce runoff
volumes, pollutant loadings, and the overall effects of existing development on the affected
receiving waters.
In general, implementing integrated LID practices can result in enhanced environmental
performance while at the same time reduce development costs when compared to traditional
stormwater management approaches of collection, piping, and pond storage for treatment by
settling. LID techniques promote the use of natural systems, which can effectively reduce
nutrients, pathogens, and metals from stormwater through runoff volume reduction, filtration,
and other processes. These systems can be designed to accommodate or bypass larger flows
when large rain events occur, when the LID practice is sized for small rain events.
Cost savings can be achieved in reduced infrastructure, particularly in new development where
land is available for surface practices, because the total volume of runoff to be managed is
minimized through infiltration and evapotranspiration. By working to mimic the natural water
cycle, LID practices protect downstream resources from pollutants and adverse hydrologic
impacts that can degrade stream channels and harm aquatic life.
The use of LID does present challenges in operations and maintenance (O&M) because of the
highly distributed nature of the controls. The large number and distributed nature of LID
practices makes it challenging to track, inspect and maintain them. Depending on how the
program is implemented, many LID practices can be on private property within drainage
easements obtained for that purpose. New institutional frameworks for managing LID operations
responsibly are being developed and will continue to be developed.
It is important to note that LID designs usually incorporate more than one type of practice or
technique—in series as a treatment train or parallel to manage small drainage areas. That
approach helps to provide integrated treatment of runoff from a site. For example, in lieu of a
treatment pond serving a new subdivision, planners might incorporate a bioretention area in
each yard, disconnect downspouts from driveway surfaces, remove curbs or cut out drainage
slots into curbs, and install grassed swales in common areas. The basis of LID is integrating
small practices throughout a site instead of using extended detention wet ponds for treatment
purposes.
Planning techniques such as smart growth minimize runoff by approaches such as
enhancing density along existing transportation and other infrastructure corridors, and reducing
sprawl and greenfield development. While one aspect of smart growth—increased population
density where appropriate—has been perceived as potentially conflicting with LID approaches
3-20 Chapter 3. Urban and Suburban
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
that have typically been considered as land-
intensive for infiltration, in actuality they can be
compatible and complementary. In dense, high-
rise urban areas, stormwater management
practices such as expanded street tree boxes,
building-front infiltration planter boxes, green
roofs and permeable pavement with infiltration
potential, can provide improved water quality and
needed aesthetic relief from endless paved and
concrete surfaces. During warm weather, the
urban heat island effect is intensified by the
paved surfaces. The need for integrating green
stormwater management will become more
essential as people move into and live in dense
areas.
• Conservation of resources by reinvesting
in existing infrastructure, infill
development, reclaiming historic
buildings, with denser growth along
transit.
• Design of neighborhoods that have
shops, offices, schools and other
amenities near homes, giving residents
and visitors the option of walking,
bicycling, taking public transportation, or
driving
• Economically competitive, desirable
places to live, work, play
Conservation designs minimize runoff by
conserving undeveloped land and reducing the
amount of impervious surface, which can cause increased runoff volumes. Open space can be
used to treat the increased runoff from the built environment through infiltration and
evapotranspiration. For example, developers can use conservation designs to preserve
important features on the site such as wetland and riparian areas, forested tracts, and areas of
pervious soils. Development plans that outline the smallest site disturbance minimize stripping
topsoil and compacting subsoil. Such simplistic, nonstructural methods reduce the need to build
runoff controls like retention ponds for treatment and larger stormwater conveyance systems,
thereby decreasing the overall project cost. Reducing the total area of impervious surface by
limiting road widths and parking areas also reduces the volume of runoff that must be treated.
Conservation designs benefit residents and their
quality of life because of increased access and
proximity to communal open space, a greater
sense of community, and expanded recreational
opportunities. Some literature notes more
developer profit from conservation designed
subdivisions compared to conventional
subdivisions (Mohamad 2006), but others note
that regulations requiring clustered-type designs
might be needed where lot size alone appears to
be a stronger driver of value to consumers
(Kopitsetal. 2007).
of
• Cluster development
• Undeveloped land conservation
• Reduced pavement widths (streets,
sidewalks)
• Shared driveways
• Reduced setbacks (shorter driveways)
• Site fingerprinting during construction
Chapter 3. Urban and Suburban
3-21
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
LID practices are engineered structures or landscape features designed to capture and
infiltrate, store, convey, or filter runoff in a manner that attempts to replicate predevelopment
hydrology.
Infiltration practices can also be used to achieve a goal of recharging groundwater while at the
same time reducing runoff. Recharging groundwater is especially important in areas where
maintaining drinking water supplies and stream baseflow is of special concern because of
limited precipitation or high withdrawal demands. Infiltration of runoff can also help to maintain
stream temperatures because the infiltrated water that moves laterally to replenish stream
baseflow typically has a lower temperature than overland flows, which might be subject to solar
radiation. Another advantage of infiltration practices is that they can be integrated into
landscape features in a site-dispersed manner. This feature can result in aesthetic benefits and,
in some cases, recreational opportunities; for example, some infiltration areas can be used as
playing fields during dry periods.
Runoff storage practices reduce the volume and
peak rate of runoff to protect streams from the
erosive forces of high flows, and irrigate landscaping
to providing aesthetic benefits such as more
sustainable (i.e., more self-watering) landscape
islands, tree boxes, and rain gardens. Designers
can take advantage of the space beneath paved
areas like parking lots and sidewalks to provide
additional storage. For example, underground vaults
can be used to store runoff in both urban and rural
areas, and street tree designs have been developed
to better enable use of that space for root growth to
enable establishment of healthy urban tree canopy.
Runoff Storage Practices
• Parking lot, street, and sidewalk
storage in underground infiltrating
vaults
• Rain barrels and cisterns
• Depressional storage in landscape
islands and in tree, shrub, or turf
depressions
• Green roofs
Runoff conveyance practices can be used to slow
flow velocities, lengthen the runoff time of
concentration, and delay peak flows that are
discharged off-site. LID conveyance practices can
be used as an alternative to curb-and-gutter
systems. LID conveyance practices often have
rough vegetative surfaces that reduce runoff
velocities and allow settling of solids. They promote
infiltration, filtration, and some biological uptake of
pollutants. LID conveyance practices also can
perform functions similar to those of conventional
Runoff Conveyance Practices
• Eliminating curbs and gutters
• Creating grassed swales and grass-
lined channels
• Roughening surfaces
• Creating long flow paths over
landscaped areas
• Creating terraces and check dams
3-22
Chapter 3. Urban and Suburban
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
curbs, channels, and gutters. For example, they can be used to reduce flooding around
structures by routing runoff to landscaped areas for treatment, infiltration, and
evapotranspiration.
Filtration practices capture pollutants by physical
filtration of solids or cation exchange of dissolved ._... .. _, ..
Filtration Practices
pollutants. They also reduce runoff volume, recharge
• Bioretention/ram gardens
groundwater, increase stream baseflow, and reduce
thermal impacts. Pollutant buildup can be of concern, * Ve9etated swales
and pollutants are typically captured in the upper soil • Vegetated filter strips/buffers
horizon. Captured pollutants can be removed by
replacing the topsoil. The useful life of the media can be
extended by selecting plants that also provide
phytoremediation.
Conservation Landscaping
Conservation landscaping reduces labor, * Plantin9 native- drought-tolerant plants
watering, and chemical use. Properly preparing • Converting turf areas to shrubs and trees
soils and selecting species adapted to the site . Reforestation
increases the success of plant growth, stabilizing
.. . . • Encouraging longer grass length
soils and allowing for biological uptake of
pollutants. Pest resistance (reducing the need for • Plantin9 wildflower meadows rather than
pesticides) and improved soil infiltration from root turf along medians and in open space
growth are among the goals. Conservation . Amending soil to improve infiltration
landscaping is promoted by many entities in the . |ntegrgted pest management
Chesapeake Bay area and elsewhere.
1.1.4.3 Benefits of Designing to Restore and Preserve Predevelopment
Hydrology
Unlike traditional stormwater management, an approach to maintain or restore predevelopment
hydrology meets multiple performance objectives and can offer additional benefits, including the
following:
Pollution abatement. LID practices more reliably reduce pollutant loadings by reducing the
runoff volume. LID practices, to a lesser degree, can reduce pollutants by settling, filtering,
adsorption, and biological uptake.
Protect downstream water resources. LID practices help to prevent or reduce hydrologic
effects on receiving waters, reduce stream channel degradation from erosion and
Chapter 3. Urban and Suburban 3-23
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
sedimentation, improve water quality, increase water supply, and enhance the recreational and
aesthetic value of our natural resources. Other potential benefits include reduced incidence of
illness from swimming and wading, more robust and safer seafood supplies.
Protect integrity of streams and floodplains to preserve ecological functions. Costs of
streambank restoration can be reduced or avoided altogether where appropriate protection
techniques are used, in particular those techniques that maintain predevelopment hydrology
during development, redevelopment, and in retrofitting. Excess deposition of sediment in rivers
and in estuaries can be minimized by preventing upstream erosion caused by stresses resulting
from excess stormwater volume. Using LID techniques such as stormwater wetlands also can
help protect or restore floodplains, which can be used as park space or wildlife habitat (Trust for
Public Lands 1999).
Conserve energy and reduce carbon emissions in landscape irrigation and other non-
potable uses. U.S. water-related energy use—for pumping, treating and heating water—has
been estimated to be at least 521 million MWh a year. That is equivalent to 13 percent of the
nation's electricity consumption, with a CO2 output equal to the emissions of more than 62 coal
fired power plants. The Carbon Footprint of Water (Griffiths-Sattenspiel and Wilson 2009;
http://www.rivernetwork.Org/blog/7/2009/05/13/carbon-footprint-water) notes
Water conservation, efficiency, reuse and [LID] strategies should be targeted to achieve
energy and greenhouse gas emissions reductions. Research from the California Energy
Commission suggests that programs focusing on these kinds of water management
strategies can achieve energy savings comparable to traditional energy conservation
measures at almost half the cost. Water management policies that promote water
conservation, efficiency, reuse and LID can reduce energy demand and substantially
decrease carbon emissions.
If LID techniques were applied in Southern California and the San Francisco Bay area,
between 40,400 [million gallons] and 72,700 [million gallons] per year in additional water
supplies would become available by 2020. The creation of these local water supplies
would result in electricity savings of up to 637 million kWh per year and annual carbon
emissions reductions would amount to approximately 202,000 metric tons by offsetting the
need for inter-basin transfers and desalinated seawater.
As the [United States] struggles to reduce its carbon emissions in response to global warming,
investments in water conservation, efficiency, reuse and LID are among the largest and most
cost-effective energy and carbon reduction strategies available.
3-24 Chapter 3. Urban and Suburban
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
Help achieve sustainability in environmental, energy, and economic performance. The
multiple benefits can help to achieve sustainability. For example as in the requirements for
federal facilities contained in the Executive Order on Federal Leadership in Environmental,
Energy, and Economic Performance (October 5, 2009). The Executive Order includes
requirements for federal facilities to increase energy efficiency; conserve water and support
sustainable communities (http://www.whitehouse.gov/the press office/President-Obama-signs-
an-Executive-Order-Focused-on-Federal-Leadership-in-Environmental-Energy-and-Economic-
Performance/).
Groundwater recharge and stream baseflow. Growing water shortages nationwide
increasingly indicate the need for holistic water resource management strategies. Development
increases impervious surfaces and runoff. Infiltration practices replenish groundwater and
increase stream baseflow. Adequate groundwater recharge is important because low
groundwater levels can lead to low baseflows in dry weather. Greater fluctuations in stream
flows and temperatures occur when rainfall does not infiltrate, to the detriment of aquatic life.
Water quality improvements/reduced treatment costs. Keeping water clean can prevent the
costs for cleaning it up. The Trust for Public Land (1999) notes that Atlanta's tree cover has
saved more than $883 million by preventing the need for stormwater facilities. A study by the
Trust for Public Land and the American Water Works Association (2004) of 27 water suppliers
found that higher forest cover in a watershed reduced water treatment costs. According to the
study, approximately 50 percent of the variation in treatment costs can be tied to the percentage
of forest cover. It also found that for every 10 percent increase in forest cover, treatment and
chemical costs decreased approximately 20 percent, up to about 60 percent forest cover.
Reduced incidence of combined sewer overflow (CSOs). Many municipalities with older
sewer systems have CSOs. When cities were developed before the mid-1900s, sanitary
wastewater and stormwater were conveyed together to a receiving water. Wth the advent of
treatment requirements for sanitary wastewater, those combined sewers were just connected to
wastewater treatment plants. Therefore, the stormwater drainage in many older cities is
conveyed to wastewater treatment plants, and during large storm events, it exceeds the plant
capacity and overflows the raw sewage/stormwater mix into waterways. Solutions to CSOs have
focused on sewer separation and detention in large tunnels—very expensive alternatives. LID
techniques, by retaining and infiltrating runoff, reduce the frequency and amount of CSOs. For
the past several years, communities such as Portland (Oregon), Chicago, and the District of
Columbia have been piloting and implementing LID approaches aimed at reducing runoff
generated and subsequently discharged into the combined system.
Habitat improvements. Innovative stormwater management techniques like LID or
conservation design can be used to improve natural resources and wildlife habitat, or avoid
Chapter 3. Urban and Suburban 3-25
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
expensive mitigation costs. For example, in 2008 the National Marine Fisheries Service (NMFS)
determined that the National Flood Insurance Program (NFIP) administered by the Federal
Emergency Management Agency (FEMA), jeopardized endangered salmon and killer whale
populations by enabling development in environmentally sensitive floodplains. NMFS then
proposed alternative measures FEMA could take to comply with the Endangered Species Act
(ESA) and the goals of the NFIP. Such measures included additional protections for sensitive
areas and requiring LID techniques in developments (National Wildlife Federation 2008;
http://online.nwf.org/site/DocServer/Memo to Colleagues re NMFS NFIP Biop.pdf?doclD=10
562). The complete National Oceanic and Atmospheric Administration (NOAA) NMFS biological
opinion is at http://www.nwr.noaa.gov/. Another example is the Etowah Habitat Conservation
Plan (HCP) adopted by several local governments in Georgia's Etowah Basin, which includes
adoption of LID techniques by participating local governments to streamline compliance with the
ESA (www.etowahhcp.org/).
Reduced downstream flooding and property damage. LID practices, when applied
throughout a watershed, can reduce flash flooding, and reduce property damage or risk during
small storm events.
Reduce erosion and sediment loss. Designs that manage runoff on-site or as close as
possible to its point of generation reduce erosion and sediment transport, as well as stream
erosion.
Real estate value/property tax revenue. Property owners will pay a premium to be near
amenities like water features, open space, trails, and clustered subdivisions. EPA's early
Economic Benefits of Runoff Controls (USEPA 1995) described many examples. Indication of
increased value of conservation subdivisions is observed by Rayman (2006), and for protected
riparian corridors by Qui et al. (2006). The extent of willingness to pay for such an environment
lies with the consumer because there have been observations where the added value was not
observed (Kopits et al. 2007). As continuing urbanization makes natural areas more scarce and
precious, and as more of the population moves into cities for reasons such as transportation,
the characteristic of valuing green amenities should continue to be assessed to ensure that it is
captured in cost/benefit analyses.
Lot yield. In cases where LID practices are incorporated on individual house lots and along
roadsides as part of the landscaping, land that would normally be dedicated for a stormwater
pond or other large structural control can be developed with additional housing lots.
Aesthetic value. LID designs can enhance a property's aesthetics using trees, shrubs, and
flowering plants that complement other landscaping features, resulting in a perceived value of
extra landscaping.
3-26 Chapter 3. Urban and Suburban
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
Quality of life, public health, and public participation. An increasing number of studies
suggest that vegetation and green space—two key components of green infrastructure—can
have a positive effect on human health. Recent research has linked the presence of trees,
plants, and green space to reduced levels of inner-city crime and violence, a stronger sense of
community, improved academic performance, and even reductions in the symptoms associated
with attention deficit and hyperactivity disorders and other health aspects. More information on
those types of studies is at the University of Illinois at Urbana-Champaign, Landscape and
Human Health Laboratory, Human Health Benefits of Natural Landscapes Web site at
http://lhhl.illinois.edu/all.scientific.articles.htm. Placing water quality practices on individual lots
provides opportunities to enhance public awareness of their natural environment. Homeowners
often consider natural open space to be important in planned communities.
Reduce air pollution through uptake by trees. Trees remove gaseous air pollution primarily
by uptake via leaf stomata, though some gases are removed by the plant surface (Smith 1990).
In 1994 the U.S. Forest Service estimated that trees in Baltimore removed an estimated 499
metric tons of air pollution at an estimated value to society of $2.7 million (Nowak and Crane
2000).
Reducing urban heat island effect through evapotranspiration. For trees in grass-covered
areas, mid-day temperatures have been reported to be 0.7 degree Celsius (°C) to 1.3 °C cooler
than in an open area. Reduced air temperature can improve air quality because the emission of
many pollutants or ozone-forming chemicals are temperature dependent. Lower air temperature
can reduce ozone formation (Souch and Souch 1993; Nowak atwww.ufore.org)
Reduced energy costs for heating and cooling. Improved insulation against summer heat is
provided with green roofs. Mature, shady, deciduous trees can reduce air conditioning costs up
to 30 percent, while a wind break of evergreens can save 10-50 percent off heating costs in the
winter (www.dnr.state.md.us/forests/publications/urban5.html). Green roofs are also cited to
reduce urban heat island effect and provide winter insulation (Portland BES 2007).
Saving money on drainage infrastructure. Curb, gutter, storm drain pipes, and runoff
detention practices can be reduced by reducing the volume of runoff to be conveyed (WERF
2008; USEPA2007).
Example Green Infrastructure Benefits Analysis. An example of the wide array of benefits
achievable is presented in Philadelphia's Green City, Clean Water report (2009) summarizing
the vision of using LID to mitigate stormwater overflows. Philadelphia has, like many older cities,
a legacy of combined sanitary and storm sewers, and recently compared the costs and benefits
of using green infrastructure to help mitigate the CSOs to the costs of conventional stormwater
Chapter 3. Urban and Suburban 3-27
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
retrofits such as tunnels. Table 3-1 presents an overview of the types of benefits the city
envisions from a plan to implement green stormwater management.
The cost estimates for construction and maintenance can be found in the Long-Term Control
Plan at http://www.phillywatersheds.org/ltcpu/. Additional information on valuing benefits and on
the estimated capital and O&M costs of individual green infrastructure elements considered by
Philadelphia are provided in Section 2 of this chapter.
A broad overview of the ancillary benefits that can be realized from LID is provided by the
Center for Neighborhood Technology in its Green Values Calculator
(www.cnt.org/natural-resources/green-values).
Table 3-1. Projected ancillary benefits of using LID and green infrastructure stormwater practices
in Philadelphia to help achieve CSO mitigation
Economic
Benefits
Social Benefits
Environmental
Benefits
About 250 people would be employed in green jobs per year
Increase of more than 1 million recreational user-days per year would be enjoyed
Reduction of approximately 140 fatalities cause by excessive heat over the next 40
years
Increase in property values of 2%-5% in greened neighborhoods
1.5 billion pounds of carbon dioxide emissions avoided [partially through reduced
heavy equipment requirements for alternative stormwater management] or absorbed
Air quality benefits on average leading annually to 1-2 avoided premature deaths, 20
avoided asthma attacks, and 250 missed days of work or school
Water quality and habitat improvements including 5-8 billion gallons of CSO avoided
per year; 190 acres of wetlands restored or created, 11 miles of stream restored.
Reduction in electricity and fuel use [partially through reduced construction of
alternative stormwater management infrastructure].
Source: Green City, Clean Waters: Philadelphia's Program for Combined Sewer Overflow Control, A Long-Term Control
Plan Update, Summary Report, 2009. http://planphilly.com/node/9842
1.2 Overview of the Urban Runoff Chapter
This chapter provides recommendations for restoring or maintaining predevelopment hydrology
for urban runoff to maintain or restore, to the maximum extent technically feasible, the
predevelopment hydrology of the property with regard to the temperature, rate, volume, and
duration of flow.
Maintaining or restoring predevelopment hydrology is the stormwater management goal
recommended in this document, as required by Congress in section 438 of EISA for federal
development and redevelopment projects exceeding 5,000 square feet. A number of technical
3-28 Chapter 3. Urban and Suburban
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
resources, guidance, and design manuals are available that review in detail the key techniques
and topics pertinent to urban runoff control The technical material that is available in these
referenced existing sources will not be repeated here.
1.2.1 Management Practices and Management Practice Scales
The following presents an overview of the approach presented in this chapter to achieve this
goal by implementing strategies at the regional and watershed scale down to the site scale:
• At the regional or watershed scale, planning techniques such as smart growth and
policies to allow conservation development, as part of watershed planning, can be used
to lay the groundwork for ensuring that development has minimum impacts on water
resources, including no net increase in stormwater runoff. This is important for both
developed areas and for yet undeveloped areas.
• At the site scale, using green infrastructure/LID practices, along with source control and
pollution prevention, are necessary to achieve the goals of protecting and restoring the
Chesapeake Bay.
Applying LID practices at the site scale is recommended for new development, redevelopment,
and retrofit. LID practices are flexible in design, so are widely applicable. LID practices such as
functional conservation landscaping, bioretention, and swales require only a minimum
modification from traditional landscaping design, often at no additional cost, and potentially
provide long-term reductions in cost because of the reduced structural components requiring
maintenance. There might also be reduced watering costs (because runoff is infiltrated instead
of directed to drains) and turf care costs. In highly impervious urban areas where infiltration into
soils is not feasible, the traditional stormwater management approach might call for detention of
certain storm depth in a tank for water quality volume settling or peak shaving; that might not be
significantly different in capital cost from retention in a cistern for use in landscaping or toilet
flushing, and both require O&M. Appropriate practices are site-specific, as are costs. The basis
for cost comparison, i.e., the alternative management strategy, is important in determining the
extent of additional costs incurred with LID practices.
LID practices such as minimizing impervious surfaces, permeable pavement, green alleys,
green streets, cisterns and rain barrels, and green roofs have become widely accepted in cities
that have needed to manage excess pollutant runoff, water shortages, or flash flooding. The
technology is now well-proven and shown to be adaptable for implementation at new
development, redevelopment, and retrofit sites. Relatively small-scale LID practices can be
dispersed throughout a site, capturing runoff from small drainage areas for infiltration,
evapotranspiration, or capture and use. A site can be designed based on a rooftop-to-stream
treatment train approach that includes both source-control practices and runoff treatment
Chapter 3. Urban and Suburban 3-29
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
practices. The treatment train approach allows site designers and stormwater managers to take
advantage of every opportunity to prevent runoff pollution and reduce runoff volume close to its
source, thereby protecting headwater streams, municipal drainage systems, and downstream
receiving waters, as follows:
• Minimize runoff generation by limiting the amount of directly connected impervious
surface
• Capture runoff for evaporation or reuse
• Naturally infiltrate and filter runoff through landscaped areas
• Direct surplus runoff to engineered practices such as bioretention and other infiltration
devices
• Prevent contamination of runoff using pollution prevention techniques
• Manage off-site runoff using regional stormwater practices, if necessary
This guidance provides an overview of the implementation measures recommended for
managing urban stormwater to protect and restore the Chesapeake Bay or other waters
affected by development. The implementation measures are action-oriented and, when
considered together, from watershed scale to site scale, form a step-wise approach to
addressing runoff volume and pollutant concentrations and for selecting management practices.
Sections 2 and 3 of this chapter summarize key elements of this approach: volume reduction
and pollutant reduction through source control and treatment. Section 2 also addresses sectors
of development such as new development and transportation-related development and provides
references for more detailed information.
Section 4 addresses the opportunities to achieve volume reduction and pollutant reduction in
the context of redevelopments. Section 5 addresses turf management. Particularly with respect
to nutrients, that constitutes one of the most widespread land uses in the Chesapeake Bay
watershed.
Appendix 1 consists of a series of fact sheets that briefly describe some of the key practices for
which new research and guidance are available and include applicability, unit processes,
feasibility constraints and limitations, runoff volume and pollutant-load-removal estimates as
applicable, design and maintenance considerations, costs and factors that affect cost, and key
references and resources. Photos and diagrams of typical applications are also provided. The
fact sheets are intended to highlight new research and seminal resources with the most up-to-
date approach on each management practice. Those practices that are adequately covered by
other publicly available resources have links to existing sources.
3-30 Chapter 3. Urban and Suburban
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
1.2.2 Implementation Measures for Urban Runoff in the Chesapeake
Bay Watershed to Control Nonpoint Source Nutrient and
Sediment Pollution
Development or redevelopment projects with a footprint that exceeds 5,000 square feet
should use site planning, design, construction, and maintenance strategies for the
property to maintain or restore, to the maximum extent technically feasible, the
predevelopment hydrology of the watershed and site with regard to the temperature, rate,
volume, and duration of flow. (Note: That is based on the approach adopted by Congress for
federal facilities in section 438 of the Energy Independence and Security Act, 2007)
Implementation Measures:
U-l. Maximize infiltration, evapotranspiration, and harvest and use practices on-
site, to the maximum extent technically feasible. Examples of these practices
include the following:
• Bioretention cells or raingardens
• Green streets, right-of-way and parking lot designs and retrofits
• Cisterns and interior and exterior use of runoff
• Green roofs
• Tree planting and urban forestry
• Soil amendments and turf management
U-2. Implement policies to preserve or restore predevelopment hydrology with
regard to the temperature, rate, volume and duration of flow, or more
restrictive if needed for site-specific water quality protection. Implement at
the regional, watershed, and site scales, as appropriate. Consider the
following factors: land use, hydrology, geomorphology, and climate. Use
Options 1 or 2 or similar performance-based approaches to achieve the
desired hydrological goals:
• Option 1: Retain the 95th Percentile Rainfall Event (simplified method)
• Option 2: Conduct site-specific hydrologic analysis
U-3. Use planning and development techniques to direct development to areas
where development will
• Have fewer impacts on water quality
• Preserve the integrity of healthy watersheds
• Achieve local objectives for infrastructure management and sustainability
Chapter 3. Urban and Suburban 3-31
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
U-4. Use conservation design and LID techniques to
• Minimize the hydrologic impacts of the development and preserve
natural drainage ways to the extent feasible
• Integrate green infrastructure (GI)/LID practices into the design and
construction of the development, to the extent feasible and preferably at
the neighborhood scale
U-5. Examine federal facilities planning guidance, design manuals, and policies
(municipalities would examine codes and ordinance, and industry or other
facilities would examine corporate policy directives and guidance) for
opportunities to revise and update
• Street standards and road design guidelines
• Parking requirements
• Setbacks (requirements for long driveways, and the like)
• Height limitations (encourage density where appropriate)
• Open space or natural resource plans
• Comprehensive plans or facility master plans
U-6. Examine and revise transportation, right-of-way and parking lot policies,
guidance, and standards to reduce impervious areas and water resource
impacts.
U-7. Minimize directly connected impervious areas in new development,
redevelopment, and in retrofits by
• Disconnection of downspouts
• Infiltration of runoff onsite (preferably through bioretention practices)
• Product substitution, e.g., use of permeable paving materials
• Harvest and use of runoff onsite
• Construction of green roofs
U-8. Restore streams, floodways, and riparian areas to mitigate channel erosion
and sedimentation and enhance the pollutant removal capacity of these areas.
U-9. Reduce the impacts of existing impervious areas through redevelopment and
infill policies and strategies and identify and implement incentives for
redevelopment that encourage the use of GI/LID designs and practices
3-32 Chapter 3. Urban and Suburban
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
Retrofit existing urban areas to achieve the desired performance goals
Assess candidate sites, prioritize, and implement practices based on
expected cumulative benefit to the subwatershed or watershed
Assess retrofit potential of significant runoff sources such as streets,
highways, parking lots, and rooftops.
Develop and implement redevelopment programs that identify
opportunities for a range of types and sizes of redevelopment projects to
mitigate water resource impacts that
- Establish appropriate redevelopment stormwater performance
standards consistent with the goal of restoring predevelopment
hydrology with regard to the temperature, rate, volume and duration
of flow, or more restrictive if needed for site-specific water quality
protection, as determined by the appropriate regulatory authority for
the region or site
- Include development of an inventory of appropriate mitigation
practices (e.g., permeable pavement, infiltration practices, green roofs)
that will be encouraged or required for implementation at
redevelopment sites that are smaller than the applicability threshold
- Include site assessment to determine appropriate GI/LID practices
- Review facility planning documents and specifications (as well as any
applicable codes and ordinances) and modify as appropriate to allow
and encourage GI/LID practices
- Implement GI/LID demonstration projects
- Incentivize early adopters of GI/LID practices
- Maximize urban forest canopy to reduce runoff
- Conduct soil analyses and amend compacted urban soils to promote
infiltration
Chapter 3. Urban and Suburban 3-33
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
Reduce Pollutant Concentrations by implementing source control measures and
treatment practices as necessary to meet water quality goals
Source Control/Pollution Prevention
Implementation Measures:
U-10. Identify the pollutants of concern (POCs) to help target the selection of
pollution prevention/source control that are most appropriate, for example,
nutrients and sediment.
U-ll. Implement pollution prevention/source control practices, i.e., nonstructural,
programmatic efforts as basic, routine land management practices to target
specific pollutants.
U-12. Require source controls on
• New and redevelopment site plans for commercial/industrial facilities
• Commercial/industrial facilities through development of a
- Stormwater Pollution Prevention Plan (SWPPP) where required for
regulated industrial categories
- Similar stormwater pollution prevention plans that might be required
by local authorities
• Municipal facilities or other designated Municipal Separate Storm Sewer
System (MS4s) permittees through development of Pollution
Prevention/Good Housekeeping programs such as the Stormwater Phase
II Minimum Control Measures.
U-13. Develop and implement ongoing outreach programs aimed at behavior
change to prevent pollution and control it at its source. Methods for impact
and effectiveness evaluation should be incorporated into these outreach and
education programs.
U-14. Implement programs for disconnection of directly connected impervious
areas, such as residential downspout disconnection programs.
U-15. Conduct inspections of commercial/industrial facilities to provide
compliance assistance or to ensure implementation of controls.
3-34 Chapter 3. Urban and Suburban
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
Runoff Treatment
Implementation Measures:
U-16. Identify the POCs to help target the type of treatment approaches that are
most appropriate.
U-17. Select treatment practices based on applicability to the POCs
• Use practices to reduce runoff volume as the preferred and most reliable
approach to reducing pollutant loading to receiving waters
• Use treatment practices as needed if reduction of runoff is not feasible
• Base the selection of treatment practice on
- Treatment effectiveness for the POC to ensure discharge quality
- Long-term maintenance considerations to ensure continued adequate
maintenance and recognition of life-cycle costs
- Site limitations to ensure appropriateness of practice to the site
- Aesthetics and safety to ensure public acceptance
Turf Management Implementation Measures
Implementation Measures:
Turf Landscape Planning and Design
U-18. Where turf use is essential and appropriate, turf areas should be designed to
maintain or restore the natural hydrologic functions of the site and promote
sheet flow, disconnection of impervious areas, infiltration, and
evapotranspiration.
Turf Management
U-19. Use management approaches and practices to reduce runoff of pollutant
loadings into surface and ground waters.
U-20. Manage turf to reduce runoff by increasing the infiltrative and water
retention capacity of the landscape to appropriate levels to prevent pollutant
discharges and erosion.
U-21. Manage applications of nutrients to minimize runoff of nutrients into
surface and ground waters and to promote healthy turf
Chapter 3. Urban and Suburban 3-35
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
• Where appropriate, consider modifications to operations, procedures,
contract specifications and other relevant purchasing orders, and facility
management guidance to reduce or eliminate the use of fertilizers
containing P
U-22. Manage turf and other vegetated areas to maximize sediment and nutrient
retention.
U-23. Reduce total turf area that is maintained under high input management
programs that is not essential for heavy use situations, e.g., sports fields and
heavily trafficked areas.
U-24. Convert nonessential, high-input turf to low-input or lower maintenance turf
or vegetated areas that require little or no inputs and provide equal or
improved protection of water quality.
U-25. Use turf species that reduce the need for chemical maintenance and
watering, and encourage infiltration through deep root development.
U-26. Conduct a facility or municipal wide assessment of the landscaped area
within the facility property or jurisdiction. This assessment should include
• A map of the jurisdiction or facility, including the identification of all turf
and other landscape areas
• An inventory or calculation of the total turf and other landscape area in
acres or hectares using GIS techniques or other methods
• An evaluation to determine essential and nonessential turf areas
• Identification and delineation of all high-input, low-input, and no-input
turf areas
• An evaluation of turf management activities and inputs, preferably by
turf category or significant turf area within the facility or jurisdiction
• An assessment of landscape cover type benefits such as pollution load
reductions and resource savings, e.g., water and energy that are provided
by each landscape cover type
• An assessment of landscape cover type health, infiltrative and pollutant
loading capacity and opportunities to increase soil health to promote the
infiltrative capacity of turf and landscape areas
• An assessment of surface water and groundwater loadings related to
high-input, low-input, and no-input turf area
3-36 Chapter 3. Urban and Suburban
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
U-27. Develop a management plan that contains
• An analysis of options to reduce or eliminate nonessential turf or convert
essential turf to low-input turf that performs optimally from a water
resource protection perspective
• An analysis of turf areas to identify opportunities to maximize water
quality benefits of landscapes in regard to runoff, in-stream flows,
infiltration, groundwater recharge and sediment, nutrient and pathogen
loadings
• A landscaping approach that integrates turf management within the
context of natural resource and habitat plans
• Stated goals and objectives regarding the reduction of turf related inputs
(water, fertilizers, pesticides, fossil fuels) and maximizing water resource
benefits on a facility- or municipality-wide basis
• An analysis of options to reduce potable water use by using cultural
practices, hardy cultivars, or recycled water or harvested runoff
• An identification of areas where soil amendments can be used to enhance
soil health and the infiltration capacity of the soils
• Areas of turf that could be used to manage runoff
• Areas of turf that could be replaced by lower maintenance cultivars or
other grasses such as switch grass
• A training program for landscaping personnel
• An implementation schedule
• An annual landscaping inventory and progress report
U-28. Develop and implement ongoing public education and outreach programs
Bay-friendly lawn, landscape, and turf management. Programs should target
behavior change and promote the adoption of water quality friendly
practices by increasing awareness, promoting appropriate behaviors and
actions, providing training and incentives. Impact and effectiveness
evaluation should be incorporated into such outreach and education programs.
Chapter 3. Urban and Suburban 3-37
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
2 Implementation Measures for Reducing Urban
Runoff Volume
The shortcomings of traditional, detention-based stormwater control efforts, and the need to use
approaches to reduce runoff volume to protect water quality, have been well-documented (NRC
2008; USEPA2009).
This section presents an approach of land use and growth management measures that guide
development to areas that minimize effects on sensitive resources and open space, and ensure
that new and redevelopment sites are designed to reduce runoff volume through on-site
stormwater retention.
Development or redevelopment projects with a footprint that exceeds 5,000 square feet
should use site planning, design, construction, and maintenance strategies for the
property to maintain or restore, to the maximum extent technically feasible, the
predevelopment hydrology of the watershed and site with regard to the temperature, rate,
volume, and duration of flow. (Note: Based on the approach adopted by Congress for federal
facilities in Section 438 of the Energy Independence and Security Act, 2007)
Implementation Measures:
U-l. Maximize infiltration, evapotranspiration, and harvest and use practices on-
site, to the maximum extent technically feasible. Examples of these practices
include
• Bioretention cells or raingardens
• Green streets, right of way and parking lot designs and retrofits
• Cisterns and interior and exterior use of runoff
• Green roofs
• Tree planting and urban forestry
• Soil amendments and turf management
U-2. Implement policies to preserve or restore predevelopment hydrology with
regard to the temperature, rate, volume and duration of flow, or more
restrictive if needed for site-specific water quality protection. Implement at
the regional, watershed, and site scales, as appropriate. Consider the
following factors: land use, hydrology, geomorphology, and climate. Use
3-38 Chapter 3. Urban and Suburban
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
Options 1 or 2 or similar performance-based approaches to achieve the
desired hydrological goals:
• Option 1: Retain the 95th Percentile Rainfall Event (simplified method)
• Option 2: Conduct site-specific hydrologic analysis
U-3. Use planning and development techniques to direct development to areas
where development will
• Have fewer impacts on water quality
• Preserve the integrity of healthy watersheds
• Achieve local objectives for infrastructure management and
sustainability
U-4. Use conservation design and LID techniques to
• Minimize the hydrologic impacts of the development and preserve
natural drainageways to the extent feasible
• Integrate green infrastructure (GI) LID practices into the design and
construction of the development, to the extent feasible and preferably at
the neighborhood scale
U-5. Examine federal facilities planning guidance, design manuals, and policies
(municipalities would examine codes and ordinance, and industry or other
facilities would examine corporate policy directives and guidance) for
opportunities to revise and update
• Street standards and road design guidelines
• Parking requirements
• Setbacks (requirements for long driveways, etc.)
• Height limitations (encourage density where appropriate)
• Open space or natural resource plans
• Comprehensive plans or facility master plans
U-6. Examine and revise transportation, right-of-way, and parking lot policies,
guidance and standards to reduce impervious areas and water resource
impacts.
U-7. Minimize directly connected impervious areas in new development,
redevelopment, and retrofit by
Chapter 3. Urban and Suburban 3-39
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
• Disconnection of downspouts
• Infiltration of runoff onsite (preferably through bioretention practices)
• Product substitution, e.g., use of permeable paving materials
• Harvest and use of runoff onsite
• Construction of green roofs
U-8. Restore streams, floodways, and riparian areas to mitigate channel erosion
and sedimentation and enhance the pollutant removal capacity of these
areas.
U-9. Reduce the impacts of existing impervious areas through redevelopment
and infill policies and strategies and identify and implement incentives for
redevelopment that encourage the use of GI/LID designs and practices.
• Retrofit existing urban areas to achieve the desired performance goals
• Assess candidate sites, prioritize, and implement practices based on
expected cumulative benefit to the subwatershed or watershed
• Assess retrofit potential of significant runoff sources such as streets,
highways, parking lots, and rooftops
• Develop and implement redevelopment programs that identify
opportunities for a range of types and sizes of redevelopment projects to
mitigate water resource impacts that
- Establish appropriate redevelopment stormwater performance
standards consistent with the goal of restoring predevelopment
hydrology with regard to the temperature, rate, volume and duration
of flow, or more restrictive if needed for site-specific water quality
protection, as determined by the appropriate regulatory authority for
the region or site
- Include development of an inventory of appropriate mitigation
practices (e.g. permeable pavement, infiltration practices, green roofs)
that will be encouraged or required for implementation at
redevelopment sites that are smaller than the applicability threshold
- Include site assessment to determine appropriate GI/LID practices
- Review facility plans and specifications (as well as any applicable
codes and ordinances) and modify as appropriate to allow and
encourage GI/LID practices
3-40 Chapter 3. Urban and Suburban
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
• Implement GI/LID demonstration projects
• Incentivize early adopters of GI/LID practices
• Maximize urban forest canopy to reduce runoff
• Conduct soil analyses and amend compacted urban soils to promote
infiltration
2.1 Maximize Infiltration, Evapotrans pi ration, and
Harvest and Use
Restoring or maintaining predevelopment hydrology has emerged as the generally preferred
approach for controlling urban runoff and protecting water quality for several reasons. Most
importantly, this approach addresses the root cause of impairment. Traditional control
approaches attempt to control the symptoms (e.g., peak flow, excess pollutants), but that is
largely ineffectual in protecting streams and water quality because of the scale of the problem,
the cumulative effects of multiple developments, and the need to manage both site- and
watershed-level effects. The problems associated with traditional control approaches in
protecting water quality are presented in the Introduction to this chapter. This section presents
the approaches for obtaining the goal of restoring or maintaining predevelopment hydrology.
To maintain or restore site or watershed hydrology, the watershed should function hydrologically
after development as it did before human induced land alterations. In the Chesapeake Bay,
most areas before development were forested with mature trees, and the bulk of the rainfall was
intercepted, infiltrated, or evapotranspired.
To mimic the natural behavior of the landscape, the stormwater management system should be
designed to manage runoff through the following:
• Infiltration and groundwater recharge
• Evapotranspiration
• Harvest rainfall and use of captured rainfall on-site
On sites where inadequate area or the intended use of the development precludes managing
the desired volume on-site, off-site mitigation should be considered within the same
subwatershed.
Chapter 3. Urban and Suburban 3-41
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
2.2 Implement Policies to Preserve and Restore
Predevelopment Hydrology
This guidance provides two options that site designers can use to establish appropriate
performance goals to maintaining or restoring predevelopment hydrology; however, note that in
many situations, it might be feasible and beneficial to have no runoff from a site. The discussion
of the two options does not preclude the use of more protective performance goals. Option 1,
the methodology based on retention of the 95th percentile rainfall event, is a simple way to
establish the performance goal and does not require detailed analysis of the site conditions or a
continuous simulation modeling approach. It is assumed that using that performance standard
will generally result in designs that protect or restore site hydrology. However, there could be
situations where Option 1 (retaining the 95th percentile rainfall event) is not protective enough to
maintain or restore the predevelopment hydrology of the project (for example, in some
headwater streams) or is overprotective (in the case of naturally impermeable surfaces). In such
cases, Option 2 (site-specific hydrologic analysis) could be used to determine the performance
design objective necessary to preserve predevelopment runoff conditions. The expectation is
that Option 2 can be used in situations where the designer has the requisite data and resources
to analyze site infiltration, evapotranspiration, interception, and potential harvest and use
scenarios to establish these design objectives and to design the runoff management system to
meet the goals of maintaining and restoring site hydrology. More detailed descriptions of the two
options follow.
Option 1: Retain the 95th Percentile Rainfall Event
Under Option 1, managers design, construct, and maintain stormwater management practices
that manage rainfall on-site, and prevent the off-site discharge of the precipitation from all
rainfall events less than or equal to the 95th percentile rainfall event to the Maximum Extent
Technically Feasible (METF). The 95th percentile rainfall event is the event whose precipitation
total is greater than or equal to 95 percent of all storm events over a given period of record. For
example, to determine what the 95th percentile storm event is in a specific location, all 24-hour
storms that have recorded values over a 30-year period would be tabulated, and a 95th
percentile storm would be determined from that record, i.e., 5 percent of the storms would be
greater than the number determined to be the 95th percentile storm. Thus the 95th percentile
storm would be represented by a number such as 1.5 inches, and that would be the design
storm. The designer selects a system of practices, to the METF, that infiltrate, evapotranspire,
or harvest and reuse that volume multiplied by the total area of the facility/project footprint.
Methods and data used to estimate the 95th percentile event are discussed in Appendix 2 of this
chapter.
3-42 Chapter 3. Urban and Suburban
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
For the purposes of this document, retaining all storms up to and including the 95th percentile
storm event is analogous to maintaining or restoring the predevelopment hydrology with respect
to the volume, flow rate, duration, and temperature of the runoff for most sites.
Where technically feasible, the goal of Option 1 is that 100 percent of the volume of water from
storms less than or equal to the 95th percentile event over the footprint of the project should not be
discharged to surface waters. In some cases, runoff can be harvested and used and ultimately
can be discharged to surface waters or a sanitary treatment system; such direct or indirect
discharges must be authorized. For example if runoff is captured for nonpotable uses such as
toilet flushing or other uses that are not irrigation related, the waters could be discharged into the
sanitary sewer system or other appropriate system depending on local requirements.
Runoff volumes that exceed the 95th percentile event can be managed by using overflow or
diversion strategies and practices as well as the detention practices used for flood control.
Designers should also account for potential thermal effects of structures such as roofs and
paved surfaces that can increase the temperature of stormwater runoff. Designers should select
materials that minimize temperature increases (consider material such as concrete versus
asphalt; vegetated roofs, and the like and use them as appropriate).
Rationale for Selecting Option 1. Retention
of 100 percent of all rainfall events equal to or
less than the 95th percentile rainfall event was
estimated to be a representation of the natural
hydrology on most sites as a default value. On
most sites, little or no runoff occurs from small,
frequently occurring storms, and such storms
account for a large proportion of the annual
precipitation volume. When development
occurs, the hydrologic balance of the site is
disturbed and as a result runoff occurs from
both small and large storms. There is an
increase in the number of runoff events, and
an increase in the runoff volume, duration,
rate, and temperature. Receiving water
degradation and habitat loss occur from this
changed hydrologic regime.
Table 3-2 contains representative 95th
percentile storm event volumes in inches from
rth
Table 3-2. Example 95 percentile storm
events or select U.S. cities
City
Baltimore, MD
Binghamton, NY
Charleston, WV
Elmira, NY
Harrisburg, PA
Lynchburg, VA
Norfolk, VA
Richmond, VA
Salisbury, MD
Washington, DC
Williamsburg, VA
95th percentile event
rainfall total
(in)
1.6
1.2
1.2
1.2
1.4
1.5
1.7
1.7
1.7
1.5
1.4
Source: Adapted from Hirschman and Kosco 2008
Chapter 3. Urban and Suburban
3-43
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
selected cities in the Chesapeake Bay watershed. Figure 3-10 contains a plot representing
storm event frequency for Washington, DC. In Figure 3-10, the 95th percentile storm event has
been identified and is approximately 1.5 inches.
0.0
0%
Percentile
rth
Figure 3-10. Rainfall frequency spectrum showing the 95 percentile rainfall event for Washington,
DC (Reagan National Airport -1.5 inches).
the 95th
This chapter's Appendix 3 contains information on how to calculate the 95th percentile rainfall
event for a specific area. A long-term record of daily rainfall amounts (such as 30 years) is
needed to calculate long-term precipitation values (Chang 1977; Boughton 2005). When
selecting the length of record to use, consider the potential effects of climate change in the
region—for example, has the rainfall pattern changed over the past few decades, and if so,
should a safety factor be included in case the trend continues?
Designers opting to use Option 1 would need to do the following:
1. Calculate or verify the precipitation amount from the 95th percentile storm event (that
number would be typically expressed in inches, e.g., 1.5 inches)
3-44
Chapter 3. Urban and Suburban
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
2. Employ on-site stormwater management controls to the METF that infiltrate,
evapotranspire, or harvest and use the appropriate design volume
• The 95th percentile event can be calculated by using the following procedures below
(summarized from Hirschman and Kosco. 2008. Managing Stormwater in Your
Community: A Guide for Building an Effective Post-Construction Program, Center for
Watershed Protection): Obtain a long-term rainfall record from a nearby weather station
(daily precipitation is fine, but try to obtain at least 30 years of daily record). Long-term
rainfall records can be obtained from many sources, including NOAA at
www.nesdis.noaa.gov
• Remove from the data set all data for small rainfall events that are 0.1 inch or less and
snowfall events that do not immediately melt. Such events should be deleted because
they do not typically cause runoff and could cause the analyses of the 95th percentile
storm runoff volume to be inaccurate.
• Use a spreadsheet or simple statistical package to sort the rainfall events from highest to
lowest. In the next column, calculate the percentage of rainfall events that are less than
each ranked event (event number / total number of events). For example, if there were
1,000 rainfall events and the highest rainfall event was a 4-inch event, 999 events are
less than the 4-inch rainfall event (or a percentile of 999 /1,000, or 99.9 percent).
• Use the rainfall event at 95 percent as the 95th percentile storm event.
Option 2: Site-Specific Hydrologic Analysis
Under Option 2, the predevelopment hydrology would be determined on the basis of site-
specific conditions and local meteorology by using continuous simulation modeling techniques,
published data, studies, or other established tools. The designer would then identify the
predevelopment condition of the site and quantify that the post-development runoff volume and
peak flow discharges are equivalent to predevelopment conditions. The post-construction rate,
volume, duration and temperature of runoff should not exceed the predevelopment conditions,
and the predevelopment hydrology should be replicated through site design and other
appropriate practices to the METF. Additional discussions of appropriate methodologies to use
in assessing site hydrology have been included in Appendix 3.
The predevelopment hydrologic condition of the site is the combination of runoff, infiltration, and
evapotranspiration rates and volumes that typically existed on the facility site before
development on a greenfields site (meaning any construction of infrastructure on undeveloped
land such as meadows or forests). In practice, determining the predevelopment hydrology of a
site can be difficult if no suitable reference site is available. As a result, reference conditions for
typical land cover types in the locality often are used to approximate what fraction of the
Chapter 3. Urban and Suburban 3-45
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
precipitation ran off, soaked into the ground, or was evaporated from the landscape. Using
reference conditions can be problematic if suitable data are not available or unique site
conditions exist that do not fit within a typical land use cover type for the area, e.g., meadow or
forest. The intent is not to restore the site to pre-Columbian conditions but to develop or
redevelop the site to ensure that a stable hydrologic regime is in place to protect groundwater,
surface water, and receiving stream channel stability.
For redevelopment sites, existing site conditions and uses of the site can influence the amount
of runoff that can be managed on-site through infiltration, evapotranspiration, and harvest and
use and, thus, affect the achievement of the performance design objective. In the context of
some redevelopment projects, fully restoring predevelopment hydrology can be difficult to
achieve. In such cases, EPA recommends using a systematic analysis to determine what
practices can be implemented. The Technical Guidance on Implementing the Stormwater
Runoff Requirements for Federal Projects under Section 438 of the Energy Independence and
Security Act, EPA 841-B-09-001 (USEPA 2009e), (http://www.epa.gov/owow/nps/lid/section438)
provides methodology for federal facilities in determining METF. Examples of conditions that
could prevent a fully restored predevelopment hydrology are a combination of the following:
• The presence of shallow bedrock; contaminated soils, near-surface groundwater; or
other factors such as underground facilities or utilities.
• The design of the site precludes the use of soil amendments, plantings of vegetation or
other designs that can be used to infiltrate and evapotranspirate runoff.
• Water harvesting and reuse are not practical or possible because the volume of water
used for irrigation, toilet flushing, industrial make-up water, wash-waters, and the like, is
not significant enough to warrant designing and using water harvesting and reuse
systems.
• Modifications to an existing building to manage stormwater are not feasible because of
structural or plumbing constraints or other factors as identified by the facility
owner/operator.
• Small project sites where the lot is too small to accommodate infiltration practices
adequately sized to infiltrate the volume of runoff from impervious surfaces.
• Soils that cannot be sufficiently amended to provide for the requisite infiltration rates.
• Situations where site use is inconsistent with the capture and reuse of stormwater or
other physical conditions on-site that preclude the use of plants for evapotranspiration or
bioinfiltration.
3-46 Chapter 3. Urban and Suburban
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
• Retention or use of stormwater on-site or discharge of stormwater on-site via infiltration
has a significant adverse effect on the site or the downgradient water balance of surface
waters, groundwaters or receiving watershed ecological processes.
• State and local requirements or permit requirements that prohibit water collection or
make it technically infeasible to use certain green infrastructure/LID techniques.
• Retention or use of stormwater on the site would cause an adverse water balance to
either or both the receiving surface waterbody or groundwater.
In cases where a technical infeasibility exists that precludes full implementation of the
performance design goal, the facility should still use stormwater practices to infiltrate,
evapotranspire, or harvest and use on-site the maximum amount of stormwater technically
feasible.
2.3 Land Use Planning and Development Techniques to
Direct Development
2.3.1 Impacts of Land Use on Hydrology and Geomorphology
An evaluation of the land use and hydrology/geomorphology of a watershed or site is an
important first step in designing to maintain or restore predevelopment hydrology and mitigate
pollutant loading.
One of the key strategies to reduce runoff is to change the pattern of land development to one
that is less destructive to water quality. Land use is the largest driver of changes in stormwater
runoff, and developed and urbanized lands contribute the largest volumes of increased runoff.
The progression of development has led to the increased urbanization of the population. The
urbanization of land, however, has outpaced the urbanization of the population, indicative of
spraw/-type development. That trend has been witnessed nationally, and with the population of
the Chesapeake Bay area expected to continue to increase it will place more development
pressure on the watershed (NRC 2008; Beck et al. 2003).
Such urbanization patterns have significant effects on land use as the predeveloped conditions
of forests, meadows, and agricultural lands are replaced by hardened landscapes. Impervious
surfaces, such as roads and roofs are the main land cover in urban areas and have a significant
impact on stormwater quality. For example,
• Roads and parking lots are as much as 70 percent of total impervious cover in ultra-
urban areas (National Research Council 2008)
Chapter 3. Urban and Suburban 3-47
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
• Roads tend to capture and export more stormwater pollutants than other land covers in
highly impervious areas, especially for small rainfall events (National Research Council
2008)
Even urban land cover that is not hardscape does not infiltrate rainfall as it would before
development. Urban soils have much higher bulk density (the mass of dry soil divided by its
volume, which serves as a predictor of porosity) than undisturbed soils because of soil
compaction typical of construction practices and urban uses. As shown in Table 3-3 the bulk
density of urban soils is closer to concrete than to undisturbed soils. The ability of soils with
such levels of compaction to infiltrate and retain stormwater is greatly diminished and results in
greater quantities of runoff. The lack of an absorptive humus layer, and active soil biota, can
also play a role in reducing infiltration rates.
As a result of such compaction, the runoff from urban soils often resembles that of impervious
surfaces, especially for larger storm events.
Table 3-3. Bulk density of urban soils is closer to concrete than to
undisturbed soils
Material
Undisturbed Soil
Urban Lawn
Fill Soil
Soil Adjacent to Buildings and Roadways
Concrete
Bulk density
(grams per cubic centimeter)
1.1 to 1.4
1.5 to 1.9
1.8 to 2.0
1.5 to 2.1
2.2
Source: Schueler and Holland 2000
An understanding of such effects is essential to effectively mitigate them. Watershed and site
assessments enable a better understanding of the factors contributing to hydromodification, so
that appropriate mitigation techniques can be selected. The site assessment process should
evaluate the hydrology, topography, soils, vegetation, and water features (i.e., wetlands, riparian
areas, and floodplains) to identify how stormwater moves through the site before development.
Additional information on the site assessment process is provided in Section 3 of this document.
In addition, to protect stream channels from increased erosion, it is necessary to control the total
time—the duration—stream channels are subject to geomorphically significant flows. The flows
can result in channel erosion caused by the additional energy imparted to the stream channel by
the increases in runoff velocities and volumes. The extended high flows typically lead to stream
channel destabilization because the stream did not evolve under those conditions and lacks the
capacity to dissipate this increased energy without scouring the stream bed. In response, both
3-48
Chapter 3. Urban and Suburban
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
the channel and banks are incised, creating increased sediment transport. Those problems are
aggravated as the flow travels downstream, with other altered watersheds contributing their
increased volumes.
The traditional stormwater management approach was based primarily on flood protection, and
often focused on not exceeding a predevelopment flow rate, but it did not take into account
additional volume. When there is greater volume to be discharged, the duration of the peak flow
rate is longer than under predevelopment condition. When multiple discharges of this type enter
a receiving stream, the flow peaks that once were sequential become additive, creating much
higher peak flows in the stream than existed in predevelopment conditions. The relationships
between hydrologic and geomorphic changes and biological parameters can be analyzed using
protocols such as that laid out in WERF's Protocols for Studying Wet Weather Impacts and
Urbanization Patterns (WERF 2008a).
2.3.2 Appropriate Designs as Part of a Comprehensive Watershed
Plan
This section contains an overview of example strategies, policies, and practices that land
managers on different scales (federal, state, local) have used to reduce the effects of
development and redevelopment on receiving water hydrology. The strategies and approaches
used to achieve a community's hydrologic stormwater goals will depend on the scale at which
the approach is to be applied—regional, local jurisdiction, watershed, subdivision/facility
campus, or building lot. Issues and potential tools for different scales of implementation are
provided in Table 3-4.
Such strategies should be included as part of a comprehensive watershed plan to protect the
resources in the watershed and downstream. Development approaches should be viewed
across a watershed or region, down to the local scale, to help achieve communities' desired
goals for water resources while avoiding unintended consequences, such as flooding or
inadequate base stream flow. Comprehensive planning is an effective nonstructural tool to
reduce the amount of impervious surface in a watershed and to guide future development in a
manner that best protects water quality.
Water management planning is just one component of watershed planning for restoring
ecosystem function. For example, the importance of maintaining natural daylight/nighttime
conditions for the propagation of many species has recently become recognized and integrated
into facility planning (General Services Administration 2005) (P-100-2005-2.12 Landscape
Lighting, www.darkskies.org). Comprehensive watershed planning should ideally encompass a
holistic approach to sustainability.
Chapter 3. Urban and Suburban 3-49
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
Table 3-4. Strategies and tools for implementing stormwater protection goals at different scales
Scale
Example strategies at
different scales
Example programs and initiatives
National
Water Environment
Research Foundation
Using Rainwater to Grow Livable Communities
Sustainable Stormwater Best Management Practices (BMPs),
Case studies of LID program development in cities nationwide,
tools and resources targeted to specific user groups.
National Association of
Regional Councils
Promotes information exchange to help regional organizations
achieve goals.
EPA's Green Infrastructure
and LID websites, U.S.
Department of Defense LID
Policy
Provide national-level guidance
NFIP under the FEMA
NFIP and the Endangered Species Act: Implementing a salmon
friendly program by developing a reasonable and prudent
alternative; Program to prepare guidance for use in developing
flood-risk areas
Regional
Regional Commissions
facilitate cooperation (such
as similar ordinances for
development equity) and
leverage funds for outreach,
etc.
Northern Virginia Regional Commission: Example program
www.onlyrain.org.
Washington Metropolitan Council of Governments: Example
Symposium—Innovative Stormwater Controls on Roads &
Highways, November 2009
Interstate, multijurisdictional
partnerships
Chesapeake Bay Program: state, federal, academic and
nonprofit partnership.
www.chesapeakebay.net/partnerorganizations.aspx
Public-Private Partnerships
(any scale)
The Healthy Lawn and Clean Water Initiative, Chesapeake Bay
Executive Council and the fertilizer industry agree on voluntary
P reductions in fertilizer
http://archive.chesapeakebay.net/pubs/Lawn Care MOU.pdf
The Growing Home Campaign. Provides incentives for
homeowners to increase urban canopy with cost shared by
landscape industry.
www.baltimorecountvmd.gov/Agencies/environment/growinghome
University-Public-Private
Partnerships
Designing and monitoring pilot or demonstration facilities.
Outreach with university and extension programs.
Stormwater programs at Villanova, University of Maryland, and
North Carolina State University working together in partnership
Connecticut's NEMO (Nonpoint Education for Municipal
Officials) Program and Center for Land Use Education and
Research (CLEAR), http://nemo.uconn.edu
3-50
Chapter 3. Urban and Suburban
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
Table 3-4. Strategies and tools for implementing stormwater protection goals at different scales
(continued)
Scale
Local
Jurisdiction
Watershed
Example strategies at
different scales
Ordinances that allow LID,
fees to enable programs,
fines, technical assistance
Smart Growth policies
Green Street policies
Pollutant trading3 b
Use watershed-scale
hydraulic and pollutant
models to optimize control
type and location
Inter-jurisdictional
cooperation for purposes of
load management and
TMDL application
Local Watershed Groups
where Volunteers lead
projects
Fee-in-lieu or off-site
mitigation when compliance
on-site is not feasible
Total Maximum Daily Load
(TMDL) provides framework
for prioritizing efforts
Example programs and initiatives
D.C.'s Impervious Area Fee
Spotsylvania, Virginia, Ordinance
Lycoming County, Pennsylvania (Draft), prepared under PA
Act 167
Baltimore County, Maryland, designates land management
areas;
www.baltimorecountvmd.qov/Aqencies/planninq/masterplanninq/
smartqrowth.html%20
The Philadelphia Green program revitalizes and maintain
abandoned land and public spaces by partnering with
government, businesses, and the community
The Port Towns' (Maryland) 2010 Legislative Priorities include
Fund at least one Green Street in each of the Port Towns.
http://porttowns.orq
Region states are evaluating programs.0 EPA Region 3 is
evaluating the use of urban stormwater trading for the
Chesapeake Bay.
Virginia Soil and Water Conservation Board Guidance
Document on Stormwater Nonpoint Nutrient Offsets, Approved
July 23, 2009. http://townhall. Virginia. qov/L/GDocs.cfm
Models such as BMP-DSS (BMP Decision Support System)
have been used in Maryland as planning tools
Chesapeake Bay Program
EPA's Watershed Central provides blog and information:
http://wiki.epa.qov/watershed/index.php
Anne Arundel County, Maryland Master Watershed Stewards
Academy
Washington, DC, Proposed Off-Site Stormwater Mitigation Fee
Restoring the Legendary Lynnhaven Oysters:
Coordinated Actions Lower Bacteria Levels and Reopen
Shellfish Areas in the Lynnhaven River Watershed,
www.epa.qov/owow/TMDL/tmdlsatwork/pdf/lynnhaven river so
und bvte.pdf; and
www.epa.qov/owow/nps/Success31 9/state/va 3bavs.htm
Chapter 3. Urban and Suburban
3-51
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
Table 3-4. Strategies and tools for implementing stormwater protection goals at different scales
(continued)
Scale
Facility
campus or
subdivision
Building
Lot
Example strategies at
different scales
Smart Growth, Conservation
Development
General Service
Administration P-100
Guidance
LID Practices
Example programs and initiatives
Downtown Silver Spring, Maryland
Sussex County, Delaware
Arlington, Virginia's MetroRail Corridor
Lancaster County, Pennsylvania
U.S. Navy Police and Security Operations Facility, Norfolk, VA.
High Performance Federal Building Database,
http://femp.buildinqqreen.com/
Design guides for LID prepared by federal, state, and, local
entities
Notes
a. Lai, H. 2008. Nutrient Credit Trading: A Market-based Approach for Improving Water Quality NTSC/NRCS/USDA;
www.wsi.nrcs.usda.gov/products/w2q/mkt based/docs/nitroqen credit tradinq.pdf
b. USEPA. 2003b. Fact Sheet: Water Quality Trading Policy, www.epa.gov/owow/watershed/tradinq/2003factsheet.pdf: and
USEPA 2003b. Water Quality Trading Policy, www.epa.gov/owow/watershed/trading/finalpolicv2003.pdf
c. Chesapeake Bay Foundation. No Date. Facfs about Nutrient Trading from the Chesapeake Bay Foundation,
www.cbf.org/Document.Doc?id=141
A watershed approach is a flexible framework for managing water resource quality and quantity
within specified drainage areas, or watersheds. A watershed plan is a strategy that provides
assessment and management information for a geographically defined watershed, including the
analyses, actions, participants, and resources related to developing and implementing the plan.
Typical steps in watershed plan development include the following:
• Characterize existing conditions
• Identify and prioritize problems
• Define management objectives and procedures for documenting outcomes compared to
objectives
• Develop protection or remediation strategies
• Implement and adapt selected actions as necessary
• Document activities a watershed
The watershed approach includes stakeholder involvement and management actions supported
by sound science and appropriate technology. Resources for preparing watershed plans are
provided in Table 3-5.
3-52
Chapter 3. Urban and Suburban
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
The strategy selected for protecting and restoring watershed hydrology depends on the existing
condition of the landscape: new development strategies have a different focus than retrofit
activities in an existing urban landscape. Where redevelopment or infill development occurs,
measures and practices to restore the predevelopment hydrology should be used, although a
different suite of approaches might be more suitable than those recommended for new
development.
Table 3-5. Resources for preparing watershed plans
Reference
National Management Measures to Control
Nonpoint Source Pollution from Urban Areas.
EPA-841-B-05-004. (USEPA 2005).
Handbook for Developing Watershed Plans to
Restore and Protect our Waters. EPA-841 B-08-
002. (USEPA 2008d).
Information provided
Provides overview of elements in developing and
implementing watershed protection plans
Describes processes and tools used to quantify
existing pollutant loads, develop estimates of load
reductions needed, identify appropriate
management measures, and track progress
2.3.3 New Development and Redevelopment Strategies to Minimize
Impacts of Development
The objective in new development is preventing additional runoff, pollutant loading, and the
corresponding degradation in the watershed. Control measures focus first on the larger scale
concepts such as smart growth (for example for overall facility siting), conservation design (for
facility campus), and the use of LID practices distributed throughout a site. Many municipal
entities have adopted such practices, and the concepts are also appropriate for use in planning
and designing federal facilities.
Development Planning Techniques such as Smart Growth
New development creates extensive areas of impervious cover and increased runoff volumes.
The developments are necessarily supported by additional roads and other associated
infrastructure, compounding the effects. Facilities planners, and communities, should consider
the cumulative effect of large-scale development, including the loss of natural areas and
degraded streams and rivers.
Decisions about where and how to develop affect water quality perhaps more than any other
factor. Preserving and restoring natural landscape features (such as forests, floodplains, and
wetlands) is an integral part of green infrastructure. Efficient land use such as redeveloping
already degraded sites can also serve to protect ecologically sensitive areas from development.
Underused shopping centers or excess parking lot area can be targeted for development
Chapter 3. Urban and Suburban
3-53
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
cost-effectively when considering that the supporting infrastructure is likely already in place. An
example is the Naval Facilities Engineering Command Building 33 (NAVFAC Building 33),
where the project's reuse of a brownfield site and reuse of an existing building were its most
prominent green features (High Performance Federal Buildings Database,
http://femp.buildinggreen.com/overview.cfm?proiectid=495).
Development planning techniques such as smart growth should be used to accomplish the
multiple goals of sound development with minimum detrimental effects on water quality. Sound
principles of both smart growth and water quality protection can be achieved by using these
approaches for new development, redevelopment, and retrofit. To achieve the common goals of
smart growth and water quality protection, new development should be within or adjacent to
existing development when possible.
The increases in local government costs of sprawl development patterns include increased
costs for water distribution, sewer collection networks and maintenance, and increased school
bus transportation cost. Locating facilities away from core services, and drawing accompanying
housing development with it, could contribute to those types of costs. Note that it is difficult to
state which growth pattern is ultimately the most challenging financially to a community as
population pressures increase (Stephenson et al. 2001).
Examples of guidance for planning development are provided in Table 3-6. While such
documents are usually prepared with a focus on municipal planning, the concepts are also
applicable in many cases to federal facilities. Those documents also contain information on the
water quality benefits provided by the pollution-avoidance strategies.
The Smart Growth Network has established the 10 primary principles of Smart Growth, which
are listed in Figure 3-11. Many of these principles indirectly mitigate the impacts of growth on
water resources, but the three listed in bold font, in particular, can be used to reduce or avoid
the stormwater related impacts of both new development and redevelopment.
While several of the principles of smart growth apply, ones that can be most readily used to
reduce the hydrological impacts of development and redevelopment activities are as follows:
• Conserve Undeveloped Land to preserve critical environmental areas. This maintains
natural riparian buffers, floodplains, natural drainage ways, predevelopment hydrology,
and watershed functions. Protecting natural areas such as forests, grasslands, and
wetlands, and other open spaces that serve to filter, infiltrate, and evapotranspirate
rainfall and snowmelt help maintain the stability of the watershed.
3-54 Chapter 3. Urban and Suburban
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
Table 3-6. Existing guidance on municipal smart growth approaches that are also applicable to
federal facilities planning
Document
Using Smart Growth Techniques as Stormwater Best
Management Practices,
www.epa.aov/dced/stormwater.htm
Smart Growth for Clean Water: Helping Communities
Address the Water Quality Impacts of Sprawl,
National Association of Local Governmental
Environmental Professionals, Trust for Public Land,
ERG
www.nalqep.orq/publications/PublicationsDetail.cfm?
LinkAdvlD=42157
Protecting Water Resources with Higher-Density
Development, www.epa.qov/dced/water densitv.htm
(USEPA2010C)
Water Quality Scorecard: Incorporating Green
Infrastructure Practices at the Municipal,
Neighborhood, and Site Scales
www.epa.qov/dced/water scorecard.htm
Developing A Sustainable Community: A Guide to
Help Connecticut Communities Craft Plans and
Regulations that Protect Water Quality
http://nemo.uconn.edu/publications/LIDPub.pdf
Highlights
Detail policies and techniques that are integral
non-structural stormwater practices
Identifies approaches that can improve water
quality, profiles successful local partnerships,
and identifies barriers and solutions to
implement smart growth for clean water
programs.
Provides research and example scenarios of
how higher densities might better protect
water quality — especially at the lot and
watershed levels.
Provides policy guidance and case studies for
protecting open space, promoting infill,
designing better streets and parking lots, and
adopting site-level green infrastructure
practices.
A guide to help users focus on where LID
these practices can be integrated into a
development policies.
Direct Development to Existing Communities and Infrastructure to reduce the
development of greenfields. This makes use of existing transportation networks, and
reduces sprawl and the addition of new impervious surfaces. Redevelopment of existing
communities and Brownfields can result in positive water quality impacts and limits the
changes in land cover in undeveloped areas that result in stormwater volume increases
(for more detail, see the redevelopment section of this chapter).
Use Compact Site Design to reduce the extent of land disturbance, minimize
infrastructure requirements to service the community, and reduce the overall impervious
footprint (also see Conservation Design below).
Chapter 3. Urban and Suburban
3-55
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
• Create Range of Housing Opportunities and Choices: Providing quality housing for people of all
income levels is an integral component in any smart growth strategy.
• Create Walkable Neighborhoods: Walkable communities are desirable places to live, work, learn,
worship, and play and, therefore, are a key component of smart growth.
• Encourage Community and Stakeholder Collaboration: Growth can create great places to live,
work and play—if it responds to a community's own sense of how and where it wants to grow.
• Foster Distinctive, Attractive Communities with a Strong Sense of Place: Smart growth
encourages communities to craft a vision and set standards for development and construction that
respond to community values of architectural beauty and distinctiveness, as well as expanded choices
in housing and transportation.
• Make Development Decisions Predictable, Fair and Cost Effective: For a community to be
successful in implementing smart growth, the private sector must embrace it.
• Mix Land Uses: Smart growth supports the integration of mixed land uses into communities as a
critical component of achieving better places to live.
• Preserve Open Space, Farmland, Natural Beauty and Critical Environmental Areas: Open space
preservation supports smart growth goals by bolstering local economies, preserving critical
environmental areas, improving our communities quality of life, and guiding new growth into existing
communities.
• Provide a Variety of Transportation Choices: Providing people with more choices in housing,
shopping, communities, and transportation is a key aim of smart growth.
• Strengthen and Direct Development Toward Existing Communities: Smart growth directs
development toward existing communities already served by infrastructure, seeking to use the
resources that existing neighborhoods offer, and conserve open space and irreplaceable natural
resources on the urban fringe.
• Take Advantage of Compact Building Design: Smart growth provides a means for communities to
incorporate more compact building design as an alternative to conventional, land-consumptive
development.
Source: The Smart Growth Network: www.smartarowth.org/about/principles/default.asp?res=1024#top
Figure 3-11. The 10 primary principles of smart growth.
3-56 Chapter 3. Urban and Suburban
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
2.4 Use Conservation Design and LID Techniques
While planning techniques such as smart growth focus on where to locate development and
redevelopment, conservation design techniques promote the best practices to mitigate the
impacts of properly sited development. The design goal is to minimize the overall hydrologic
modifications by protection of natural areas and ecosystem functions. Whereas watershed
planning and smart growth address the landscape or regional scale, conservation design and
LID practices address the community and site scales. Conservation design methods include the
following (City of Portland 2004):
• Fitting development to the terrain to minimize land disturbance
• Confining construction activities to the least area necessary and away from critical areas
• Preserving areas with natural vegetation (especially forested areas) as much as possible
• On sites with a mix of soil types, locating impervious areas over less permeable soil
(e.g., till), and trying to restrict development over more porous soils (e.g., outwash)
• Clustering buildings together
• Minimizing impervious areas
• Maintaining and using the natural drainage patterns
Existing guidance on conservation design is provided in Table 3-7.
Table 3-7. Existing guidance on conservation design approaches for municipal planning that also
apply to federal facilities
Document
Conservation Design for Stormwater Management: A Design
Approach To Reduce Stormwater Impacts from Land Development
and Achieve Multiple Objectives, Delaware Department of Natural
Resources and Environmental Control and The Environmental
Management Center of the Brandywine Conservancy, 1 997
www.dnrec.state.de.us/DNREC2000/Divisions/Soil/Stormwater/New/
Delaware CD Manual.pdf
Randall Arendt, Growing Greener: Putting Conservation into Local
Plans and Ordinances, National Lands Trust-American Planning
Association-American Society of Landscape Architects, 1 999.
Site Planning for Urban Stream Protection, Tom Schueler/
Metropolitan Washington Council of Governments, 1995,
www.mwcoq.orq/store/item.asp?PUBLICATION ID=56
Center for Watershed Protection
www.cwp.ora/Resource Library/Better Site Desian/index.htm
Highlights
Approaches, design procedures,
and case studies.
Evaluates the regulatory and
zoning issues for implementing
conservation design strategies
Reduce pollutants and protect
aquatic resources through
improved construction site
planning.
Library of References
Chapter 3. Urban and Suburban
3-57
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
Implementing these methods often requires an evaluation of institutional issues that influence
growth and development. Using policies requiring compacting development, conserving open
space, and protecting environmental assets is often impeded by facility planning guidance, or
for municipalities, zoning requirements (Arendt 1999). When considering using conservation
design policies to protect water resources, the issues should be examined both to determine if
existing policies are promoting excess impervious area, and to identify impediments that could
preclude adoption or implementation of more environmentally sound designs.
GI/LID Practices and the Treatment Train Approach
Many types of LID practices exist, with many variations of each practice. Projects are most
successful when practitioners integrate them into a site design and use them in a treatment train
approach. In such an approach, the overflow from one practice flows into a second or third
practice, such as a green roof followed by a cistern, with the overflow to a planter box with its
own overflow and underdrain. Site conditions, applicable performance requirements, and cost
typically influence the selection of appropriate LID practices. Table 3-8 lists some of the major
types of practices, and a fact sheet or link for each is provided in Appendix 1.
Table 3-8. Typical LID practices
LID BMPs for site plans
Alternative Turnarounds3
Development Districts3
Green Design Strategies3
Narrower Residential Streets3
Protection of Natural Features3
Street Design and Patterns3
Conservation Easements3
Eliminating Curbs and Gutters3
Infrastructure Planning3
Open Space Design3
Riparian/Forested Buffer3
Urban Forestry313
Site-scale LID practices
Bioretention (Rain Gardens)313
Green Roofs (Eco roofs)3'13
Green Parking3
Infiltration Trench3
Permeable Interlocking Concrete Pavement3
Porous Asphalt Pavement 3
Soil restoration13
Compost Blankets3
Rainwater Harvesting13
Blue Roofs with Water Harvesting13
Grassed Swales3
Infiltration Basin3
Pervious Concrete Pavement3
Vegetated Filter Strip3
Constructed wetlands13
Infiltration Practices'3
Notes
a. Fact sheet provided at
http://cfpub.epa.qov/npdes/stormwater/menuofbmps/index.cfm?action=min measure&min measure id=5
b. Fact sheet provided in Appendix 1 of this chapter
3-58
Chapter 3. Urban and Suburban
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
The performance of LID practices in reducing the annual volume of runoff varies significantly
according to the specific design of the practice and the regional climate. Depending on the site
design and area rainfall patterns, runoff can be maintained at predevelopment conditions by
careful site planning and design. Several design guides have been developed that detail the
procedures for site analysis and LID practice sizing. Some of the best design guides for LID are
provided in Table 3-9. Additional resources are listed in Appendix 2 and in the fact sheets in
Appendix 1.
Table 3-9. Example nationally applicable LID design methods and manuals
Prince George's County, Maryland, Low-Impact Development Design Strategies: An Integrated Design
Approach, EPA 841-B-00-003, 2000.
Prince George's County, Maryland, Low-Impact Development Hydrologic Analysis, EPA 841-B-00-002,
2000. www.epa.gov/nps/lid/
USEPA, Stormwater Best Management Practices Design Guide, Office of Research and Development,
EPA/600/R-04/121, Volumes 1-3 (121, 121 A, 121B), September 2004.
http://www.epa.gov/nrmrl/pubs/600r04121 /600r04121 .htm
Center for Watershed Protection Urban Subwatershed Restoration Manual Series
(http://www.cwp.org/Store/usrm.htm')
Center for Watershed Protection Managing Stormwater in Your Community: A Guide for Building an
Effective Post-Construction Program
(http://www.cwp.org/Resource Library/Center Docs/SW/pcguidance/Manual/
PostConstructionManual.pdf)
U.S. Naval Facilities Engineering Command, Low Impact Development, Draft, Unified Design Criteria,
UFC 3-210-10, October 2004. http://www.wbdg.org/ccb/DOD/UFC/ufc 3 210 10.pdf
U.S. Army Corps of Engineers. Low Impact Development for Sustainable Installations: Stormwater
Design and Planning Guidance for Development within Army Training Areas. Public Works Technical
Bulletin 200-1-62. October 2008.
Geosyntec Consultants and Wright Water Engineers. Urban Stormwater BMP Performance Monitoring.
2009. http://www.bmpdatabase.org/MonitoringEval.htm
The Low-Impact Development Center, http://www.lowimpactdevelopment.org/: several LID manuals
Specific to the Chesapeake Bay area, a literature review and assessment of the reported
performance of many LID practices was recently conducted for the region to estimate the
capability of the practices for volume control and pollutant reduction. The Mid-Atlantic Water
Program housed at the University of Maryland reviewed and compiled effectiveness estimates
for BMPs implemented and reported by the Chesapeake Bay watershed jurisdictions
(Developing Best Management Practice Definitions and Effectiveness Estimates for Nitrogen,
Phosphorus, and Sediment in the Chesapeake Bay, December 2009
(www.chesapeakebay.net/websitesearchresults.aspx?menuitem=19557). The report estimates
that the infiltration practices such as bioretention, as designed and with safety factor
considerations, could reduce runoff from the first 1-1.5 inches of runoff up to 80 percent, for the
purposes of conservatively estimating wide-scale effectiveness in the region. That depth is
Chapter 3. Urban and Suburban 3-59
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
approximately the 85th to 95th percentile storm event in the region. The report was not meant to
evaluate how currently designed practices would perform consistently in the 95th percentile
storm event. Practices to achieve retention of the 95th percentile storm event would need to be
designed for that specific target performance. Additional information on the findings are
provided in Appendix 1.1.1 Performance Estimate Summaries for Infiltration Practices and in the
Bioretention fact sheet in Appendix 1.
By using design procedures outlined in the LID manuals such as those in Table 3-9 and in
Appendix 2 of this chapter, practices can achieve runoff reduction to restore or maintain
predevelopment hydrology.
The effectiveness of conservation design using LID to reducing runoff is demonstrated in
subdivision-wide results recently reported. Sources for information on existing LID subdivisions
are provided in Table 3-10.
Table 3-10. Sources of information on existing LID subdivisions
Name, location, and reference
Performance summary
Meadow on the Hybelos, 8.27-acres Puget
Sound area in Pierce County, Washington.
www.sldtonline.com/content/view/344/75
2007 to 2008: LID subdivision designs performed
better than design objectives, and exceeded the
local requirement that post-development discharge
volume not exceed predevelopment discharge
volume. The researchers also reported that
underdrains significantly impair hydrologic
performance (WERF 2009).
Cross Plains, Wl; Burnsville, MN; Somerset, MD:
Jordon Cove, CT (ASCE/WERF/EPA
International Stormwater BMP Database, Urban
Stormwater BMP Performance Monitoring—
Geosyntec Consultants and Wright Water
Engineers 2009). www.bmpdatabase.org
Annual runoff reductions from 40% to 90% over the
monitoring period were observed, with significantly
reduced performance when rain events occurred
under already saturated conditions.
2.5 Evaluate Planning Manuals and Guides
LID approaches and practices, smart growth and conservation development strategies can all
be promoted by incorporating them into facility planning manuals and guides, similar to
municipal codes and ordinances in some cases. Some aspects of existing planning manuals
and guides can hinder LID development strategies because of the lack of understanding of the
practices that in some cases differ from the traditional Stormwater management approaches.
For example, existing planning documents might require a curb and gutter that can serve to
concentrate flows leading to increased volume of runoff to streams—one potential solution is to
either drop the requirements for curb and gutter or state that curb cuts are encouraged to
facilitate the use of roadside swale infiltration. Facility planning guides can also prevent
3-60
Chapter 3. Urban and Suburban
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
naturalized landscaping, stormwater use in toilet flushing, and rain gardens that can have
periodic short-term ponding. Resources that federal facility planners, municipal officials, and
designers can use to evaluate codes and ordinances for revision to accommodate these
approaches are provided in Table 3-11.
Table 3-11. Resources for evaluating codes and ordinances for municipalities that are applicable
for use in reviewing federal facility planning manuals, guides, and specifications
Water Quality Scorecard: Incorporating Green
Infrastructure Practices at the Municipal,
Neighborhood, and Site Scales, USEPA 201 Oe,
www.eoa.aov/dced/water scorecard.htm%20%20
Out of the Gutter, National Resources Defense
Council, July 2002
http://www.nrdc.orq/water/pollution/qutter/qutter.pdf
A Catalyst for Community Land Use Change,
National NEMO Network 2008 Progress Report:
http://nemonet.uconn.edu/about network/publicatio
ns/2008 report.htm
Puget Sound Partnership Low Impact Development
Local Regulation Assistance
www.psp.wa.qov/Proiect
Better Site Design: A Handbook for Changing
Development Rules in Your Community, Center for
Watershed Protection, 1998
www.cwp.orq/Store/bsd.htm
Plan Review checklist and flow chart, Office of
Watersheds, Philadelphia Water Department:
www.phillvriverinfo.orq/WICLibrarv/%20Developme
ntProcess Final.pdf
Audit of Pavement Standards for the Saluda-Reedy
Watershed, Mitigating the Impacts of Impervious
Surfaces in Greenville and Pickens Counties, South
Carolina, Saluda-Reedy Watershed Consortium c/o
Upstate Forever, 2006. www.upstateforever.orq
Provides policy guidance and case studies for
protecting open space, promoting infill development
over Greenfield development, designing better
streets and parking lots, and adopting site-level
green infrastructure practices.
NRDC recommends LID, for Washington, DC,
including specific observation and recommendations
for revisions to existing codes and ordinances.
Examples of local regulations for water quality
protection.
Assistance to help local governments integrate LID
into their development standards and regulations.
Examples and case studies for changing
development regulations to promote better site
design, also referred to as environmentally sensitive
design or LID.
Example of how to prioritize stormwater planning
early in the overall plan review process for
development projects.
Identifies opportunities for flexibility in street width,
parking ratios, sidewalk and driveway, and other
aspects of paving.
The following list contains the most common elements of planning design requirements that can
cause unnecessary construction of impervious surface areas that have applicability to federal
facilities (CWP 1998 Water Quality Scorecard; USEPA 2009). Facility planners, similar to
communities, should carefully review existing policy mechanisms to determine opportunities to
revise to reduce water resource effects that can result from creating impervious surfaces:
• Density patterns. Dispersing low-density development across the watershed can
negatively affect receiving waters by constructing significantly more impervious surfaces.
Chapter 3. Urban and Suburban
3-61
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
• Street standards or road design guidelines are used to dictate the width of the road,
turning radius, street connectivity, and intersection design requirements. Facility
planners should review street and road standards to determine if road designs can be
changed to reduce impervious surface cover and still meet transportation and safety
requirements.
• Parking requirements are generally set to the minimum, not the maximum, number of
parking spaces required for retail and office parking..
• Setbacks are used to define the required distance between a building and the right-of-
way or lot line. Many setback requirements specify the use of long driveways.
Establishing maximum setback lines for buildings can reduce the creation of
unnecessary impervious surface areas by bringing buildings closer to the street.
• Height limitations are used to limit the number of floors in a building. Limiting height can
spread development out if square footage is unmet by vertical density.
• Open space or natural resource plans are used to identify land parcels that are or will be
set aside for recreation, habitat corridors, or preservation. Such plans help communities
prioritize their conservation, parks, and recreation goals and protect important areas
from development.
• Comprehensive plans might be required by state law, and many cities, towns, and
counties prepare comprehensive plans to support zoning codes. Federal facilities might
have an opportunity to contribute to achieving the region's goals in the plan. Most
comprehensive plans include elements that are intended to address land use, open
space protection or creation, natural resource protection, transportation, economic
development, and housing. These elements are important facets of a comprehensive
watershed protection approach. Increasingly, local governments are identifying areas of
existing green infrastructure and outlining opportunities to add new green infrastructure
throughout the community to protect water resources.
2.6 Evaluate Transportation-Related Standards
Minimize/reduce impervious areas by using techniques such as reduced street widths and
parking areas. Many urban and suburban streets are sized to meet code requirements for
emergency service vehicles, on-street parking, and free flow of traffic. Such code requirements
often result in streets being oversized for their typical everyday functions. The Uniform Fire
Code requires that streets have a minimum 20 feet of unobstructed width; a street with parking
on both sides would require a width of at least 34 feet. In practice, many suburban and urban
streets can be much wider than that as local design practices have increased street widths to 40
and 50 feet. Those designs result in increased runoff and associated pollutant loadings. In sum,
3-62 Chapter 3. Urban and Suburban
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
the two issues are often (1) planning documents often require excessively wide streets and do
not specify a maximum width; and (2) the minimum requirement for widths is often exceeded.
Just decreasing the amount of impervious surface in itself might not provide substantial
stormwater benefits if the adjacent soils are highly compacted. Combining the reduced street
width with the installation of swales or amended soil filter strips, or by using tree pits (even
extending under paved sidewalks) to collect stormwater will provide enhanced performance.
Many communities have adopted narrower street width standards while also accommodating
emergency vehicles by developing alternative street-parking configurations, designing adequate
turnarounds, prohibiting parking near intersections, providing vehicle pullout space, and using
smaller block lengths. Examples are provided in Table 3-12. A key to identifying and
successfully codifying narrow street widths is coordination among departments, including fire,
transportation, and public works.
Table 3-12. Examples of adopted narrow street widths
Jurisdiction
Phoenix, AZ
Orlando, FL
Birmingham, Ml
Howard County, MD
Kirkland, WA
Madison, Wl
Street width
(feet)
28
28
22
26
20
24
12
20
24
28
27
28
Parking condition
parking both sides
parking both sides, res. Lots < 55 feet wide
parking both sides, res. Lots > 55 feet wide
parking both sides
parking one side
parking unregulated
alley
parking one side
parking both sides — low-density only
parking both sides
parking both sides, <3DU/AC
parking both sides, 3-10 DU/AC
ADT: Average Daily Traffic; DU/AC: dwelling units per acre
Source: Adapted from Cohen 2000; CWP 1998.
http://www.stormwatercenter.net/Assorted%20Fact%20Sheets/Tool4 Site Design/narrow streets.htm
The need to accommodate bike lanes and sidewalks adds to the pressure to increase width,
making efficient design and incorporating permeable pavements where appropriate, even more
important. Holistic design concepts such as Complete Streets
(www.greenhighwayspartnership.org) describe broader function goals consistent with the focus
of environment protection, such as lighting to prevent unnecessary glare and interference with
off-road nighttime conditions.
Chapter 3. Urban and Suburban
3-63
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
Integrating green streets into overall development and redevelopment projects provides many
opportunities for improving environmental and energy performance. For example, the small
town of West Union, Iowa, evaluated combining its planned green street retrofit with a
separately planned, energy-saving project to convert the central business district to sustainable
geothermal energy. By adding pipes to convey excess geothermal energy underneath the
planned permeable pavement in the green street, the town estimated it could save money in
shoveling and plowing, reduce risk of ice patches, reduce salting costs, and, as a side-benefit,
reduce salt runoff to the trout stream in the watershed. Such a project might not be achievable
for capital cost reasons in many cases, but the long-term cost-savings it provides demonstrates
that it is well worth evaluation (http://www.iowalifechanging.com/communitv/downloads/West-
Union-lowa-Green-Streets-Pilot-Proiect-Summary.pdf).
Zoning requirements often require that parking be provided for the maximum business day,
resulting in unused parking and impervious area for the majority of the year. Reassessing the
actual needed parking area can minimize impervious area.
Green street and highway design is necessary to help mitigate the effects of stormwater runoff
from those surfaces using roadside infiltration. A proven example of a green street is Seattle's
pilot Street Edge Alternatives Project (SEA Streets), Figure 3-12, completed in 2001. It is an LID
design that provides drainage that more closely mimics the natural landscape before
development. Seattle Public Utilities accomplished this by reducing impervious surfaces to 11
percent less than a traditional street, by providing surface detention in swales, and adding more
than 100 evergreen trees and 1,100 shrubs. Monitoring shows that the design has successfully
reduced the volume of stormwater runoff by 99 percent
http://www.seattle.gov/util/About SPU/Drainage & Sewer System/
GreenStormwaterlnfrastructure/NaturalDrainageProiects/StreetEdgeAlternatives/index.htm.
Resources for additional information on street and highway design for LID are provided in
Table 3-13.
3-64 Chapter 3. Urban and Suburban
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
BEFORE
AFTER
Source: from http://courses.washinqton.edu/qehlstud/Precedent%20Studies/SEA Street.pdf
Figure 3-12. Seattle SEA Streets
Table 3-13. Resources for information on street and highway design for LID
Document
Green Highway Partnership (GHP), with weekly
electronic newsletter, www.greenhighways.org
Project 25-20(01): Evaluation of Best Management
Practices for Highway Runoff Control, Low Impact
Development Highway Manual, National
Cooperative Highway Research Program,
http://onlinepubs.trb.org/onlinepubs/nchrp/nchrp rpt
565.odf
Anacostia Waterfront Transportation Architecture
Design Guidelines
http://ddot.washingtondc.gov/ddot/cwp/view, a, 1249,
d.627063.ddotNav GID.1744.ddotNav.l33960l.aso
DDOT. 2005.
Portland Green Street Program, Portland, Oregon,
Bureau of Environmental Services (BES)
www.portlandonline.com/BES/index.cfm?c=44407
Tabor to the River, Portland BES
www.portlandonline.com/bes/index.cfm?c=47591
Natural Drainage Projects, Seattle, Washington,
Seattle Public Utilities (SPU),
www.seattle.gov/util/naturalsystems
Highlights
Tracks practices for green highways and green
infrastructure, including innovative storm water
management, LID and transportation legislation.
Provides scientific and economic information for
selection and design of best management
practices (BMPs) to control highway runoff,
including BMPs to treat: nutrients, TPH, PAH,
metals, pathogens, pesticides, temperature, TSS,
trash.
Guidelines for transportation design to support
the economic and environmental health of the
region, incorporating LID design practices.
Design information, project reports, technical
guides, newsletter.
Comprehensive, 500-street, watershed retrofit
program detailed.
Design information and details on LID street
design and elements, porous pavement
specification, project reports.
Chapter 3. Urban and Suburban
3-65
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
2.7 Minimize Directly Connected Impervious Areas in
New Development, Redevelopment, and Retrofit
Not all impervious areas are created equally. Impervious areas that are directly connected to the
storm sewer system convey excess stormwater volumes more rapidly and with greater impact
than impervious areas that do not have a direct connection (i.e., disconnected). The term
effective impervious area (EIA) is used to describe this concept. EIA is the measure of how
much impervious surface is directly connected to the conveyance system. One of the first steps
to mitigating the effects of imperviousness is evaluating the opportunities to disconnect it so the
rain can be infiltrated, evapotranspired, or harvested and used.
• Downspout Disconnection. Downspout disconnection is the process of separating roof
downspouts from the sewer system and redirecting roof runoff onto pervious surfaces,
most commonly a lawn, or to a stormwater management practices such as a bioretention
cell or cistern.
• Substituting Permeable Pavements for Conventional Pavements. Using permeable
pavements can reduce directly connected impervious area because pervious materials
are substituted for impervious materials while maintaining the intended function.
Permeable pavements can be used to infiltrate stormwater, making areas that were once
a source of stormwater a means of reducing the volume of runoff. Similarly, green roof
retrofits reduce the imperviousness of rooftops by using engineered soil media and
vegetation to lower the runoff potential.
• Maximizing Opportunities to Infiltrate, Evapotranspirate, and Harvest and Use.
Disconnect flows using infiltration and evapotranspiration by incorporating bioretention
into street designs.. Bioretention features can be tree boxes that collect stormwater
runoff from the street (similar to conventional tree boxes), planter boxes, curb
extensions, or bioswales. To adapt to street configurations, grades, soil conditions, and
space availability, a range of shapes, sizes, and layouts can be used. Using existing
rights-of-way and using techniques such as curb cuts to facilitate stormwater movement
away from directly connected drainageways and into infiltration features are common
practices.
Rainwater harvesting has recently become recognized as a stormwater management tool
because of its ability to reduce stormwater runoff volumes from impervious surfaces. It also
serves as a source substitute for potable water and can enhance water supplies and decrease
the cost and impacts of supplying water to urban areas. Collected rainwater is ideal for
nonpotable applications, such as landscape irrigation, toilet and urinal flushing, cooling system
make-up, and vehicle washing. Such collection and use is a key component of an integrated
water resources management approach. Performance of rainwater harvesting systems depends
on the volume of water stored and the demand for the stored water.
3-66 Chapter 3. Urban and Suburban
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
Rainwater harvesting has been practiced by civilizations for centuries, and is now actively used
in many countries that experience chronic or seasonal water shortages. In this country, though,
rainwater harvesting has been primarily used for flash flooding control, or otherwise managing
drainage problems. Now, in states such as Georgia, Virginia, and Texas, government-supported
organizations have prepared manuals and guidelines for residential and commercial water
harvesting for drought preparedness. For a listing of manuals and other resources, see the fact
sheet in Appendix 1. In the Northwest, residential and commercial rainwater harvesting is used
for stormwater management. In western cities, rainwater harvesting is becoming more
common—Los Angeles County and Tucson, Arizona, for example—but water rights issues
could restrict its use in some states.
Design and installation manuals relevant to the Chesapeake Bay area, references to example
city ordinances, and other information on rainwater harvesting is provided in the fact sheet in
Appendix 1.
2.8 Implement Restoration
2.8.1 Native Landscapes and Urban Tree Canopy
Restoring native landscapes in drainage pattern and in plant selection can be an important
component of restoring predevelopment hydrology. Information on native landscaping is
available from many state and local governments and sources listed in the Section 5 Turf
Management, and in the fact sheets in Appendix 1.
In the Chesapeake Bay watershed, trees constitute a large part of the native landscape and
play a major role in the water cycle. That is not the case with other, arid regions, where
supporting nonnative forests could strain water resources. In the Chesapeake Bay region,
however, significant potential exists to reduce runoff volumes on an annual basis using
increased urban tree canopy. Interception in the tree canopy provides some capture in small
events, but trees can evapotranspirate significant amounts—up to 200 to 800 gallons per day
for some mature tree species (ITRC 2009). Each deciduous tree in the Baltimore area in the
2009 weather pattern evapotranspired approximately the following amounts (during leaf-on
period)(personal communication, David Nowak, U.S. Forest Service):
• 2.6 gallons/day for a small tree (1-m radius crown)
• 260 gallons/day for a large tree (10-m radius crown)
For dense urban environments—and where utility conflicts can be managed—new technologies
include the following:
• Structures or structural soils that allow root growth under sidewalks and vehicle areas.
Chapter 3. Urban and Suburban 3-67
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
• Permeable pavements that enable stormwater to flow to roots while supporting loads;
• Flexible sidewalk material (example: Belleview, Washington,
http://www.ci.bellevue.wa.us/rubber sidewalk.htm,
• Large-diameter soaking hoses or vaults built into tree pits that collect and infiltrate a first
portion of runoff for evapotranspiration.
Using those technologies, little or no additional land is consumed in managing stormwater and
some street tree maintenance issues can be better managed.
To estimate the effectiveness of adding urban tree canopy and green roofs at reducing the
stormwater runoff volumes in a dense urban environment, Casey Trees and LimnoTech
developed the Green Build-out Model to quantify the stormwater benefits of trees and green roofs
for different coverage scenarios in Washington, DC (Casey Trees 2007). The model was applied
to an intensive greening scenario and a moderate greening scenario. Nearly all the waters in
Washington, DC, are seriously polluted by urban stormwater runoff and the sewage overflows it
causes. The Green Build-out Model demonstrates that trees and green roofs—just a portion of the
types of infrastructure practices available—can be used to achieve substantial reductions in
stormwater runoff and sewage discharges to the rivers. Key findings show for an average year:
• The intensive greening scenario eliminates more than 1.2 billion gallons of stormwater.
• Reductions in stormwater runoff volume of up to 10 percent across the city, with up to
27 percent reductions in individual sewersheds under the most intensive greening
scenario.
• The DC Water and Sewer Authority could realize between $1.4 and $5.1 million per year
in annual operational savings in the area because of reduced pumping and treatment
costs.
• General hydrological relationships, including unit area planning factors, and modeling
methodologies that are transferable to other municipalities.
Using trees to help manage stormwater and protect water quality is increasingly accepted by
some engineers and land managers as sustainability becomes more important in land design. A
statement by the Chesapeake Bay Executive Council in 2006 emphasizes the point:
Forests are the most beneficial land use for protecting water quality, due to their ability to
capture, filter, and retain water, as well as air pollution from the air. Forests are also
essential to the provision of clean drinking water to over 10 million residents of the
watershed and provide valuable ecological services and economic benefits including
carbon sequestration, flood control, wildlife habitat, and forest products.
3-68 Chapter 3. Urban and Suburban
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
A summary of resources for estimating stormwater management benefits of tree canopy are
provided in Table 3-14. Additional information is provided in the Reforestation/Urban Forestry
and Bioretention Fact Sheets in Appendix 1.
Table 3-14. Resources for estimating stormwater benefits of tree canopy and vegetation
Citygreen software by American Forests (201 Oa)
www.americanforests.orq/productsandpubs/citvareen
Trees Reduce Stormwater website by American Forests
(201 Ob)
www.americanforests.ora/aravtoareen/stormwater
i-Tree suite of software Tools from USDA Forest Service
www.itreetools.ora
Phytotechnology Technical and Regulatory Guidance,
The Interstate Technology & Regulatory Council, 2009
Casey Trees, Washington, D.C. Green Build-out Model.
2007. www.casevtrees.ora/plannina/areener-
development/abo/index.php
Analyzes the ecological and economic
benefits of tree canopy and other green
space.
Tools enable quantification on a per tree
basis or on a watershed scale.
Provides guidance on using vegetation for
soil remediation, and estimates of
transpiration rates.
The Green Build-out Model demonstrated
that trees and green roofs can be used to
achieve substantial reductions in stormwater
runoff and sewage discharges to the rivers.
2.8.2 Streams, Floodways, and Riparian Areas
Using stream and floodplain restoration, managers attempt to restore the ecological and
hydrological functions and processes of a stream and its floodplain. The stream corridor is
typically considered to consist of the stream channel, riparian zone, and flood plains (level areas
near the channel, formed by the stream and flooded during moderate-to-high flow events).
Stream corridors are influenced by the cumulative effects of upland and upstream activities and
practices, including agricultural production, forestry, recreation, other land uses, or urban
development. Specific restoration goals can include flood control, sediment control, improving
drainage, stabilizing banks, and improving habitat. Correcting stream damage using stream
restoration techniques is a costly undertaking with uncertain rewards; preventing the damage by
using the techniques described in this guidance is a more reliable approach.
Restoring impaired waterways—in particular restoring the connection to the stream's floodplain
to enable the streambank to overtop and spread excess flows out along the land to reduce
velocity and allow for off-channel ponding and infiltration the length of the stream—is important
to restoring predevelopment hydrology and reducing loading from larger and scouring flows.
Degraded streams can themselves become a source of downstream pollution, such as when
phosphorus-laden sediments are mobilized during high-flow events. In such cases, stream
restoration can be a useful strategy to improve downstream water quality. It is important that the
elevated flows causing sediment mobilization must also be addressed. Stream stabilization
requires restoration of the stream's energy signature. The predevelopment hydrology of the
Chapter 3. Urban and Suburban
3-69
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
watershed should be restored to regain the predevelopment character of the stream; however,
in existing urban areas that might be a longer-term goal. In urban areas, restoration by
successive steps in the watershed and the stream might be desired.
A summary of existing information of the effects of stream hydromodification on the quality of
the Chesapeake Bay is provided in Table 3-15. The studies demonstrate the importance of
stream restoration and protection in achieving pollutant reduction in the Chesapeake Bay,
particularly for sediment and the phosphorus that accompanies sediment loading.
Table 3-15. Studies quantifying the impact of sediment loading stream hydromodification on
Chesapeake Bay water quality
Study
A Summary Report of Sediment Processes in
Chesapeake Bay and Watershed, U.S. Geological
Survey, Water-Resources Investigations Report 03-4123,
2003
Schueler, T. The Practice of Watershed Protection,
Technical Note #119 from Watershed Protection
Techniques 3(3):729-734, Center for Watershed
Protection, 2000.
U.S. Environmental Protection Agency. 2001 . Protecting
and Restoring America's Watershed's: Status, Trends,
and Initiatives in Watershed Management, EPA 840-R-
00-001.
www.epa.qov/owow/nps/urbanm/pdf/urban quidance.pdf.
Gellis, Allen C. et al. Synthesis of U.S. Geological Survey
Science for the Chesapeake Bay Ecosystem and
Implications for Environmental Management, Chapter 6:
Sources and Transport of Sediment in the Watershed.
2007, U.S. Geological Survey Circular 1316.
Gellis, A.C. et al. 2009, Sources, transport, and storage
of sediment in the Chesapeake Bay Watershed. U.S.
Geological Survey Scientific Investigations Report 2008-
5186
Devereux, Olivia H., et al., Suspended-sediment sources
in an urban watershed, Northeast Branch Anacostia
River, Maryland. Hydrological Processes, Accepted
2009.
Findings
Summarizes the impacts and sources of
sediment and notes that sediment yield
from urbanized areas can remain high after
active construction is complete because of
increased stream corridor erosion from
altered hydrology
Stream enlargement, and the resulting
transport of excess sediment, is caused by
urban development
Straightened and channelized streams carry
more sediments and other pollutants to their
receiving waters. Up to 75% of the
transported sediment from the Pocomoke
watershed on the Eastern Shore of
Maryland was found to be erosion from
within the stream corridor
Sediment sources are throughout the
Chesapeake Bay watershed, with more in
developed and steep areas
In the Piedmont region, streambank erosion
was a major source of sediment in
developed Little Conestoga Creek; 30% of
sediment from the Mattawoman Watershed
on the Coastal Plain (flat land) is from
streambanks
Streambank erosion was the primary source
of sediment in the Northeast Branch
Anacostia River
3-70
Chapter 3. Urban and Suburban
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
Stream restoration can help to restore the natural ecosystem function of N removal that occurs
in streams. Studies that evaluate the N removal ability of restored streams are summarized in
Table 3-16.
Table 3-16. Studies evaluating the N removal ability of restored streams in the Chesapeake Bay
watershed
Study
Finding
Kausal, Sujay S., et.al. Effects of Stream
Restoration on Denitrification in an Urbanizing
Watershed. Ecological Applications, 18(3), 2008,
pp. 789-804.
Streams with ecological functions intact remove N
at a much higher rate than degraded urban
streams, and stream restoration practices can
restore this N removal function.
Klocker, Carolyn A, et. al. Nitrogen uptake and
denitrification in restored and unrestored streams
in urban Maryland, USA. Aquatic Sciences,
Accepted October 2009.
Degraded urban streams, deeply eroded and
disconnected from their floodplain, have
substantially lower rates of N removal that than
streams hydraulically connected to their riparian
banks via low slopes. Reconnecting the stream to
the floodplain can increase N removal rate.
In addition to the water quality improvements that can be achieved through stream restoration,
the flood management community has become increasingly aware of the benefits of restoration
in preventing flood damages. The Association of State Floodplain Managers has prepared a
white paper called Natural and Beneficial Floodplain Functions: Floodplain Management—More
than Flood Loss Reduction (www.floods.org), which emphasizes the multiple benefits of
protecting and restoring streams and their associated floodplains.
Techniques for stream and floodplain restoration are described in the Hydromodification section
of this document. Example references for stream restoration, and for information on the effects
of urban runoff on stream ecosystems, are provided in Table 3-17.
Table 3-17. References on urban stormwater effects on streams with emphasis on restoration and
habitat
USDA Natural Resources Conservation Service, Part 654 Stream Restoration Design
National Engineering Handbook, 210-VI-NEH, August 2007
Federal Interagency Stream Restoration Working Group (FISRWG) (1998J. Stream Corridor
Restoration: Principles, Processes, and Practices, ISBN-0-934213-60-7, Distributed by the National
Technical Information Service at 1-800-533-6847.
Infiltration vs. Surface Water Discharge: Guidance for Stormwater Managers, Final Report. 03-SW-4,
Water Environment Research Foundation (WERF 2006) Appendix B. Assessment of Existing
Watershed Conditions: Effects on Habitat.
Chapter 3. Urban and Suburban
3-71
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
2.9 Reduce Impacts of Existing Urban Areas
2.9.1 Retrofits
Many urban areas were developed without any or with few stormwater controls designed to
protect water quality and prevent stream channel degradation. This section of the document
contains recommendations for practices that can be used in such areas to try to reverse
degradation that has already occurred by reducing the volume, rates, and duration of runoff.
Specifically, the recommended control measures on existing urban land focus on retrofits to roof
downspouts, roads, parking lots, and areas of compacted soils. While these suggestions are
focused on stormwater management effectiveness, consideration should also be given to
aesthetics when designing, and using a multidisciplined design team (engineer, landscape
architect, maintenance staff) can result in more successful retrofits.
An effective retrofit strategy for urbanized areas combines planning techniques such as smart
growth and green infrastructure/LID techniques. A comprehensive guide on retrofits for existing
urban areas is the Center for Watershed Protection's (CWP's) Urban Stormwater Retrofit
Practices (CWP 2007).
The CWP's Urban Stormwater Retrofit Practices manual focuses on stormwater retrofit
practices that can capture and treat stormwater runoff before it is delivered to the stream. The
manual describes both off-site storage and on-site retrofit techniques that can be used to
remove stormwater pollutants, minimize channel erosion, and help restore stream hydrology.
Guidance on choosing the best locations in a subwatershed for retrofitting is provided in a series
of 13 profile sheets. The manual then presents a method to assess retrofit potential at the
subwatershed level, including methods to conduct a retrofit inventory, assess candidate sites,
screen for priority projects, and evaluate their expected cumulative benefit. The manual
concludes by offering tips on retrofit design, permitting, construction, and maintenance
considerations.
Table 3-18 presents common locations where additional storage and infiltration for stormwater
can be provided in a subwatershed, and also common locations for on-site retrofits.
3-72 Chapter 3. Urban and Suburban
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
Table 3-18. Common locations for additional stormwater storage and infiltration and on-site
retrofits
Common on-site retrofit locations in a subwatershed
Where
Road Right of
Ways
Near Large
Parking Lots
Conveyance
Systems
Hots pot
Operations
Small Parking
Lots
Individual
Streets
Individual
Rooftops
Little Retrofits
Hardscapes
Landscapes
Underground
How
Direct runoff to a depression or excavated stormwater bioretention/infiltration
treatment area within the right-of-way of a road, highway, transport or power line
corridor. Prominent examples include highway cloverleaf, median and wide right-of-
way areas.
Provide stormwater infiltration treatment in open spaces near the downgradient
outfall of large parking lots (5 acres plus).
Investigate the upper portions of the existing stormwater conveyance systems (such
as ditches) to look for opportunities to improve the performance. That can be done
either by creating in-line storage cells (small dams with overflows) that allow
infiltration or by splitting flows to off-line infiltration/treatment areas in the drainage
corridor.
Install filtering or bioretention treatment to remove pollutants from confirmed or
severe stormwater hotspots discovered during field investigation.
Insert stormwater treatment, preferably depressed bioretention or expanded tree
boxes, in or on the margins of small parking lots (less than 5 acres). In many cases,
the parking lot is delineated into a series of smaller, on-site treatment units.
Look for opportunities with the street, its right-of-way, cul-de-sacs and traffic calming
devices to infiltrate and treat stormwater runoff before it gets into the street storm
drain network.
Disconnect downspouts from storm drains, store and use the rainwater, and infiltrate
excess stormwater runoff close to the source.
Convert or disconnect isolated areas of impervious cover to infiltration and
bioretention, and treat excess runoff in an adjacent pervious area using low tech
approaches such as a filter strip.
Reconfigure the drainage of high-visibility urban landscapes, plazas, and public
spaces to capture and use, infiltrate and evapotranspirate, and treat excess
stormwater runoff with landscaping and other urban design features.
Provide stormwater infiltration or treatment in an underground location when no
surface land is available for surface treatment. Use this as a last resort at dense,
ultra-urban sites.
Chapter 3. Urban and Suburban
3-73
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
Examples of LID road retrofits in the Chesapeake Bay watershed are included in Table 3-19.
Table 3-19. Examples of Maryland LID road retrofits
Site
Knollbrook Drive and Talbert
Lane median and the Ray
Road stormdrain outfall in the
Takoma Branch subwatershed
U.S. Route 1 and Maryland
Route 201 at I-95
(Bioretention)
Decatur Street Improvement,
Edmonston, MD (holistic green
street — multiple LID retrofits)
Route 202 Median
(Bioretention)
Route 201 Median
(Bioretention)
Peace Cross Green Highway
Project — NW Prince George's
County, adjacent to the
Anacostia River. Network:
• Baltimore Avenue
• Bladensburg Road
• Annapolis Road
Route 202/I-495 interchange
(Bioretention)
Reference
Final Technical Report, Pilot Projects for LID Urban Retrofit Program,
In the Anacostia River Watershed, Phase IV, USEPA: Prince Georges
County, Maryland, 2007
www.princeqeorqescountvmd.qov/Government/Aqencvlndex/DER/ES
G/pdf/Final Technical Report Phase lll.pd
www.lowimpactdevelopment.orq/qreenstreets/proiects.htm;
http://edmonston.us.com/GreenStreetGroundbreakinq.html
www.co.pq.md.us/Government/Aqencvlndex/GoinqGreen/pdf/2009-
annual-qreen-report.pdf
www.co.pq.md.us/Government/Aqencvlndex/GoinqGreen/pdf/2009-
annual-qreen-report.pdf
www.princeqeorqescountvmd.qov/Government/Aqencvlndex/DER/ES
G/pdf/Final%20Technical%20Report Phase%20lll.pdf
www.sprinqerlink.com/content/l682122767u41k7x/fulltext.pdf
www.co.pq.md.us/Government/Aqencvlndex/GoinqGreen/pdf/2009-
annual-qreen-report.pdf
2.9.2 Redevelopment
Implementing an effective redevelopment program is essential to restoring water quality, as
discussed previously in this document. Section 4 of this chapter provides information on important
issues that should be addressed in redevelopment policies and example practices that are
appropriate for redevelopment. Figure 3-13 lists the stormwater retrofit and redevelopment
programs that several cities have adopted or are piloting using green infrastructure/LID
approaches. Implementation measures for redevelopment programs include establishing
appropriate redevelopment performance standards, creating an inventory of appropriate mitigation
practices for a range of project sizes, conducting site assessments as part of practice selection,
review of planning policies (similar to municipal codes and ordinances), implementing
demonstration projects, maximizing forest canopy, and mitigating compacted soils.
3-74
Chapter 3. Urban and Suburban
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
Some Municipal Highlights for Retrofit and Redevelopment Approaches and Practices:
Portland, Oregon, Bureau of Environmental Services: A Sustainable Approach to Stormwater Management,
http://www.portlandonline.com/bes/index.cfm?c=34598
Seattle, Washington, Seattle Public Utilities Natural Drainage Systems: Green Stormwater Infrastructure,
http://www.seattle.qov/util/About SPU/Drainaqe & Sewer Svstem/GreenStormwaterlnfrastructure/index.htm
Kansas City, Missouri, 10,000 Raingardens Program, www.rainkc.gov
Philadelphia, Pennsylvania, Greenworks Philadelphia, www.phila.gov/green
EPA's Green Infrastructure Web site: Case Studies of Green Municipalities,
http://cfpub.epa.gov/npdes/greeninfrastructure/gicasestudies.cfrrtfMunicipal
Figure 3-13. Municipal Stormwater retrofit/redevelopment programs can provide insight to federal
facilities for retrofit opportunities.
2.10 Costs of Green Infrastructure/LID Practices
This cost section provides sources for estimates of capital and O&M costs for individual
practices and provides information that a policymaker or designer can use to help ensure that
the cost savings and other benefits from GI/LID practices are considered during the decision
process. This section presents examples from across the country that show how GI/LID
practices compare financially to conventional Stormwater management approaches.
The examples highlight municipal programs, but the concepts are applicable to cost evaluations
on federal facilities.
The information is presented in the following format:
• Key factors in evaluating costs of GI/LID (section 2.10.1)
- Planning and development processes that have a focus on LID and pollution
prevention can help minimize the cost of implementing LID at the site level.
- Flexibility of LID allows for practices to be integrated cost-effectively.
- Opportunities for cost savings have been demonstrated and should be incorporated
where feasible.
- Environmental impacts downstream are a real and significant cost to society that
should be included in determinations of development costs.
Chapter 3. Urban and Suburban 3-75
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
- Ancillary benefits such as vegetated urban spaces and habitat should be included
when assessing the value of stormwater management alternatives.
• Types of cost analysis that can support decision making and examples (section 2.10.2)
- Capital Cost assessment: Capitol Region Watershed District, Minnesota, and
Lenexa, Kansas
- Life-cycle cost analysis: Portland, Oregon, and Commonwealth of Virginia
- Cost-effectiveness analysis: Mecklenburg, North Carolina, and New York City
- Include ancillary benefits in life-cycle cost analysis
• Local example: Philadelphia, Pennsylvania
• Regional example: Sun Valley Watershed in Los Angeles
• Costs of individual practices (Section 2.10.3)
- Issues to be considered when evaluating reported costs
- Sources of cost information
2.10.1 Key factors in evaluating costs of Green Infrastructure/LID
Planning and Development Processes
The most important practices to help ensure minimum cost for protecting water quality are the
planning and development processes and their products, i.e., the master planning documents,
specifications, municipal codes and ordinances, and other tools that promote development that
minimize detrimental effects. Incorporating water quality protection into those processes does
not cost more and provides multiple other benefits in addition to water quality. Implementing an
LID approach, while site specific in application, can be more cost-effectively achieved when
incorporated into an overall development policy. That can facilitate cost-effective designs and
improved performance by
• Enabling developers and designers to understand that stormwater requirements are to
be addressed in initial concept plans, and that the methods are acceptable to achieve a
community's goal (i.e., Spotsylvania County, Virginia, Figure 3-14, and Middlesound,
North Carolina, Figure 3-3), to reduce redesigns
3-76 Chapter 3. Urban and Suburban
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
The development community in Spotsylvania County has realized cost savings from LID, after initial
skepticism. The county lists a few of the many successful LID projects:
• A historical church in a developed area needed to add-on but could not afford land for a basin, so
instead used grass-pavers for the parking lot. An underground tank captures and infiltrates rainwater.
Originally, a 42" diameter outlet was planned, now a 6" PVC pipe works, with minimal runoff. Used a
rain garden before the drainage inlets. A 45% savings.
• Patriot Park—This development had no outlet as a result of 1930's development design.
Evapotranspiration rates were used to establish a potential water uptake. By using the required buffer
and landscaping features the traditional basin was eliminated and there would be no downstream
impact because up to a 100 yr storm event is retained on-site.
• Fence Company—The owner found that the bio-retention with underground storage cost
approximately 30% less than a traditional basin with riser and land needed. Positives noted: 1) more
land for material storage; 2) lower installation costs for installation; 3) easier to access and maintain.
"Spotsylvania has standardized agreements for BMP installation, inspection, and maintenance.
When it comes to the economics of LID practices for the most part you will not get an accurate figure until
you show your applicants how to do it right. I have had farmers, homeowners, developers and many others
say that after going through proper training courses they have found LID to be much easier than they have
seen in the books and have been led to believe."
—Richard Street, Spotsylvania County, Virginia, Department of Code Compliance, January 2010
Figure 3-14. Developers realized LID cost savings in Spotsylvania County, Virginia.
• Ensuring that the type and scale of the practices implemented are appropriate to
minimize maintenance costs and to provide amenity and habitat value for social
acceptance (Seattle SEA Streets, Washington, Figure 3-12); Portland Tabor-to-the
River, Oregon, Figure 3-2).
• Creating a market where such design and construction practices are routine to bring
down costs associated with risk perception and limited materials. For example, when
Chicago started the Green Alleys program in 2006, permeable concrete was about $145
per cubic yard; after one year, the cost dropped to $45 per cubic yard (Managing Wet
Weather with Green Infrastructure—Green Streets (USEPA 2008)). Portland's green
roof program notes that while literature values for green roofs cite an additional $5 to
$25 per square foot, a focus on the bare minimum for a functioning eco-roof has reduced
the additional cost to $3.50 to $8.00 per square foot (Portland BES 2008).
Chapter 3. Urban and Suburban 3-77
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
• Promoting practices that will help minimize overdesign and excess cost. For example,
the use of permeable pavement should enable reduction of other stormwater drainage
infrastructure (USEPA 2007).
• For some watersheds, reducing the costs of managing the increased flash flooding
accompanying build-out of previously pervious area (Capitol Region Watershed District,
Minnesota, Figure 3-19).
Flexibility for Integrating into Existing Infrastructure
Flexibility inherent in these practices allows the capture of small rain events to be integrated into
the existing developed urban environment in many cases (NRDC 2006), such as blue roofs
(New York City schools, Figure 3-15) that can serve as a first step in a treatment train to shave
peak flows or store rainwater for use; landscaping features such as traffic islands, in-ground
planters; or under-sidewalk systems (Minneapolis, Minnesota downtown MARQ2 street
redevelopment project, Figure 3-16).
Here, Blue roofs save money over conventional stormwater management practices for New
York City school system for stormwater storage.
3-78 Chapter 3. Urban and Suburban
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
In 2003, the New York City School Construction Authority (SCA) adopted a new design standard requiring
blue roofs, or roofs structurally capable of detaining water, on all new schools built citywide. In the past five
years since adopting the requirement, SCA has built 14 new schools featuring the blue roof system.
Essentially a blue roof is a drainage system that slows the rate water enters the public sewer system. Four
aspects of the blue roof system determine its function: the structural integrity of the roof, the amount of
water allowed to flow into the sewer, waterproofing of the roof, and the drain itself.
In the SCA's blue roof design, the roof drain detains up to three inches of water on the roof behind an
adjustable weir valve. Any water in excess of three inches flows over the open top of the valve and into the
sewers, but the detained water remains on the roof while being slowly filtered down the drain pipe.
For SCA, the decision to incorporate blue roofs in its design standard was driven by economics. DEP sets
standards on the allowable flow of water to enter the public sewers from buildings, based on the local
drainage plan and sewer capacity. To meet these drainage plan standards, any excess water must be
stored on-site for delayed release into the sewer. SCA eliminated the need to build costly underground
storage tanks at newly-built schools and additions by using a resource that was basically free: the roof.
Since the engineering and design are already budgeted for in a new construction project, an integrated
design to accommodate a blue roof adds very little or no additional upfront cost. And the maintenance and
upkeep is no different than with a standard-drain roof.
SCA has been very satisfied with the cost-savings blue roofs afford them in building new schools and will
continue to follow the standard in future projects.
—The City of New York PlaNYC-Sustainable Stormwater Management Plan 2008, p. 53.
Blue roof drain installed by the SCA on PS 12 (Photo credit: Council on the Environment New York
Source: Forester Media, Inc. www.Forester.net. Excerpted with permission.
Figure 3-15. Blue roofs can serve as the first step in a treatment train to retain and use.
Chapter 3. Urban and Suburban
3-79
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
To reduce traffic congestion and refurbish its downtown, Minneapolis, Minnesota, recently completed the
Marquette Avenue and 2nd Avenue (MARQ2) project, the first such effort aimed at reshaping transportation
in the Twin Cities. Stormwater mitigation was a challenge. "We have long had capacity problems with
stormwater management downtown," says Lois Eberhart, water resources administrator for the city of
Minneapolis. "We needed to find a new way of dealing with stormwater." For 48 linear blocks, Minneapolis
installed under-sidewalk structural cell frames to enable root growth for 185 trees. The project replaced
previously impervious sidewalks with pervious pavement, allowing for greater infiltration and filtration of
stormwater within the system.
Each cell group contains bioretention mix soil and can store 116 cubic feet (3.2 cubic meters) of stormwater.
Over the entire project site, that's nearly 21,600 cubic feet (611 cubic meters) of stormwater storage
capability. The system is able to capture and treat the Minneapolis 90th percentile rain event (up to 1.03
inches, in a 24-hour period).
"We've modeled a 10% reduction in peak flows to our stormwater system as a result of this installation,"
says Bill Fellows, project manager for the city of Minneapolis.
—Adapted from Stormwater Magazine, March-April 2010
www.stormh20.com/march-april-2010/reshapinq-minneapolis-proiect.aspx
Figure 3-16. Under-sidewalk bioretention provides robust street trees as stormwater management
benefit in the Minneapolis MARQ2 project.
3-80
Chapter 3. Urban and Suburban
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
Potential for Cost Savings
The potential for cost savings using LID where infiltration or drainage swales can be substituted
for piping, inlets, and other stormwater infrastructure has been well-documented. Understanding
the potential cost savings that can be achieved can help ensure that the most cost-effective
designs are prepared. EPA's report, Reducing Stormwater Costs through Low Impact
Development (LID) Strategies and Practices (EPA 841-F-07-006) (USEPA 201 Od) compares the
projected or known costs of LID practices with those of conventional development approaches.
In terms of costs, LID techniques can reduce the amount of materials needed for paving roads
and driveways and for installing curbs and gutters. Note that in some circumstances, LID
techniques might result in higher costs because of more expensive plant material, site
preparation, soil amendments, and increased project management costs. Other considerations
include land required to implement a management practice and differences in maintenance
requirements. Total capital cost savings ranged from 15 to 80 percent when LID methods were
used (Table 3-20). The full report is at www.epa.gov/nps/lid.
Table 3-20. Cost comparisons between conventional and LID approaches
Project3
2nd Avenue SEA Street
Auburn Hills
Bellingham City Hall
Bellingham Bloedel Donovan Park
Gap Creek
Garden Valley
Kensington Estates
Laurel Springs
Mill Creekc
Prairie Glen
Somerset
Tellabs Corporate Campus
Conventional
development cost
$868,803
$2,360,385
$27,600
$52,800
$4,620,600
$324,400
$765,700
$1,654,021
$12,510
$1,004,848
$2,456,843
$3,162,160
LID cost
$651,548
$1,598,989
$5,600
$12,800
$3,942,100
$260,700
$1,502,900
$1,149,552
$9,099
$599,536
$1,671,461
$2,700,650
Cost
difference15
$217,255
$761 ,396
$22,000
$40,000
$678,500
$63,700
-$737,200
$504,469
$3,411
$405,312
$785,382
$461,510
Percent
difference15
25%
32%
80%
76%
15%
20%
-96%
30%
27%
40%
32%
15%
Source: Reducing Stormwater Costs through Low Impact Development (LID) Strategies and Practices (USEPA 201 Od).
Notes:
a. Some of the case study results do not lend themselves to display in the format of this table (Central Park Commercial
Redesigns, Crown Street, Poplar Street Apartments, Prairie Crossing, Portland Downspout Disconnection, and Toronto
Green Roofs).
b. Negative values denote increased cost for the LID design over conventional development costs.
c. Mill Creek costs are reported on a per-lot basis.
Chapter 3. Urban and Suburban
3-81
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
Costs of Environmental Impacts
The environmental results of each alternative evaluated should also be considered when
assessing true costs. Damages from water quality impairments are significant—even though
they can be spatially distant from the widespread, incremental sources of excess runoff and
pollutants. They are often not considered when determining the costs of stormwater
management at the local level, but they are a true cost of stormwater management. For
example, beach closures and shellfish bed contamination, and loss of fisheries represent
significant social and economic costs to society. In addition literature available on the
Chesapeake Bay, a national overview of some of these issues is provided in EPA's 2000 report
Liquid Assets (http://www.epa.gov/water/liquidassets/execsumm.html).
Ancillary Benefits
The value of ancillary benefits that can be difficult to quantify should also be considered when
establishing the costs or value of stormwater management practices that prevent excess
volume of runoff. Examples of those types of benefits were provided in the introduction to this
chapter. Examples of where such benefits have been realized are provided later in this section.
2.10.2 Types of Cost Analysis that Can Support Decision Making
Typical components of stormwater management costs include capital costs, O&M, and program
administration. Stormwater management can also impose opportunity costs when selecting one
alternative for implementation precludes another use, such as alternative use of a piece of land
or funds.
Depending on the needs of the user, and assuming a similar level of risk and performance,
alternatives are often selected on the basis of the following:
• Capital cost assessment
• Life-cycle cost analysis (net present value)
• Cost-effectiveness to achieve a specific goal, such as cost per pound of pollutant
• Including ancillary benefits in life-cycle cost analysis
The objective of these examples is to demonstrate how communities have found LID or green
infrastructure to be an acceptable or superior alternative on a cost or cost-value basis. These
examples will not be applicable to every federal facility or community, but are intended to
illustrate the methods and factors being used by many communities to assess the cost of
various stormwater management approaches.
3-82 Chapter 3. Urban and Suburban
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
Capital Cost Assessment.
Lenexa (Kansas) and the Capital Region Watershed District (Minnesota) are examples of
communities that selected LID approaches to development and retrofit because of the lower
capital costs compared to conventional stormwater management alternatives. Their case study
examples are provided in Figures 3-17 and 3-18.
Lenexa, Kansas (population 47,000) was experiencing development pressures that led to adoption of LID-
oriented development standards and a watershed-based systems approach to stormwater management.
Program goals included reducing flooding, improving water quality, preserving the environment and open
space, and providing recreational areas and trails.
A multi-stakeholder process to evaluate the cost impacts of the proposed standard included the Lenexa
Economic Development Council and Homebuilders Association. The cost analysis evaluated different
construction types, and compared the cost of construction under the LID standards to the costs of
construction under the conventional standards. Each type of construction showed a capital cost decrease
with LID standards:
Savings Associated with Different Development Types Using LID
Development Type
Single Family
Multi-Family
Commercial/Retail
Warehouse/Office
EDUs
221
100
57
356
LID cost savings
$118,420
$89,043
$168,898
$317,483
Note: Savings includes additional developable land in addition to infrastructure. Equivalent
Dwelling Unit: 2,750 sf.
The demonstrated savings not only helped gain developer support for the ordinance and the systems-based
approach for stormwater management, but also helped ease the adoption of a development fee to help
manage increasing stormwater infrastructure needs as the community grows. The ordinance was adopted
in 2004, and 2009 polling data shows citizen satisfaction with the Public Works Department at 84%.
Sources: City of Lenexa Department of Public Works (personal communication), www.raintorecreation.orq. Beezhold,
M.T. etal(2006)
Figure 3-17. Lenexa, Kansas, demonstrates cost savings of implementing LID policies.
Chapter 3. Urban and Suburban
3-83
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
The Capitol Region Watershed District (CRWD) encompasses 41 square miles, including parts of St. Paul,
Minnesota, and five smaller cities. The watershed is 42% impervious, almost completely developed, leading to
impaired water quality and localized flooding.
In a 298 acre subwatershed of Como Lake, the initial solution to localized flooding was a second 60-inch storm
sewer at a cost of $2.5 million, which would have continued the impairment of the lake from the additional urban
runoff. In 2003, CRWD, in cooperation with local municipalities selected an alternative approach: retrofits
consisting of an infiltration facility, eight under-street infiltration trenches, eight raingardens, and a regional pond.
The infiltration design performance was 100% for the infiltration facility, 100% for the rain gardens, and 93% for
the infiltration trenches.
This approach has been a success. The following are the key benefits reported by CRWD on this project, called
the Arlington Pascal Stormwater Improvement Project (APSIP):
• Capital cost savings of $0.5 million, on a project originally estimated at $2.5 million including water
quality treatment not achieved with the original solution.
• Volume reduction (hence TP and TSS removal efficiencies) of 96% to 100%, in 2008 exceeding
design projections
• Tracking of O&M activities and costs as well as actual and modeled performance enabled the
estimation of the cost-effectiveness ($ per unit pollutant removed) of each practice (for amortized
capital plus annual O&M as "cost"). In 2007, the APSIP BMPs infiltrated over 2 million cubic feet of
runoff at a cost of $0.03/cf.
Source: Capitol Region Watershed District. 2010. CRWD Stormwater BMP Performance Assessment and Cost-Benefit
Analysis, (www.capitolreaionwd.org)
Figure 3-18. Midwest Water District achieves capital cost savings, solves localized flooding
problems, and reduces lake impairment with LID retrofits.
Life-Cycle Cost Analysis
Portland, Oregon, conducted a life-cycle cost analysis of green roofs compared to conventional
roofs. Green roofs are just one alternative being implemented in Portland to help manage the
Stormwater that causes flooding, erosion, destroys habitat, and contributes to CSOs. In the
study, a hypothetical new five-story commercial building with a 40,000-square-foot roof in
downtown Portland was evaluated. Key findings included the following:
• For the building owner (private interest), there was a net benefit over the 40-year life of
the roof of $404,000 (2008 dollars)
3-84 Chapter 3. Urban and Suburban
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
• For the public, there was an immediate and long-term benefit. At year 5, the benefit is
$101,660; at year 40, the benefit is $191,421. That does not include monetizing many
environmental benefits that are recognized but difficult to quantify.
Benefits to the public were noted to include the following:
• Reduced public costs to manage stormwater
• Avoided public stormwater infrastructure needs and O&M costs
• Reduced carbon emissions
• Improved air quality
• Increased habitat areas
Benefits to private interests were noted to include the following:
• Reduced stormwater fees
• Reduced private infrastructure and O&M costs
• Reduced energy demand and costs
• Increased roof longevity
The report concludes that the lack of an immediate, short-term benefit to an owner accounts for
the limited implementation of green roofs in Portland and beyond. The report recommends
developing economic incentives to promote the use of green roofs (or eco-roofs) to encourage
the construction in the city and to enable the city to benefit from the immediate, short-term
benefits that they provide. For federal facilities that are long-term owners or have long-term
leases, the opportunities for savings should be considered. The tabulated summary of benefits
and costs is provided in Table 3-21 (Portland BES 2008).
Whether green infrastructure practices are more costly for a site than traditional stormwater
management practices—or how much more they might cost—depends on many factors. They
include the overall development's site drainage design, the land and groundwater characteristics,
preference for site amenities, and, of primary importance, the design scenario selected for
comparison. Administrative costs for implementing a program should also be considered.
Chapter 3. Urban and Suburban 3-85
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
Table 3-21. Private and public life-cycle cost and benefits evaluation of eco-roofs
Focus area
Cost
One-time
Annual
Benefits
One-time
Annual
Summary
5-year
(in 2008 $s)
40-year
(in 2008 $s)
Private Costs and Benefits
Stormwater Manaqement
volume reduction
peak flow reduction3
Energy
cooling demand reduction
heating demand reduction
Amenity Value
amenity value3
Building
ecoroof construction cost
avoided stormwater facility
cost
increased ecoroof O&M
cost
roof longevity (over a 40-
year period)
HVAC equipment sizing
Total Private Costs and
Benefits
($230,000)
($230,000)
($600)
($600)
$69,000
$600,000
$21,000
$690,000
$1,330
~
$680
$800
_
$2,810
$6,822
~
$3,424
$4,028
_
($230,000)
$69,000
($3,077)
~
$21 ,000
$(128,803)
$45,866
~
$19,983
$23,509
_
($230,000)
$69,000
($20,677)
$474,951
$21,000
$403,632
Public Costs and Benefits
Stormwater Management
reduced system
improvements
Climate
carbon reduction
carbon sequestration3
improved urban heat island3
improved air quality
Habitat
habitat creation
Total Public Costs and
Benefits
Total Costs and Benefits
$0
$0
$60,700
$25,300
$86,000
($27,143)
$29
~
~
$3,024
$3,053
$60,700
$145
~
~
$15,515
$25,300
$101,660
$60,700
$845
~
~
$104,576
$25,300
$191,421
$595,053
Source: City of Portland, Oregon, Cost Benefit Evaluation of Eco Roofs, 2008.
a The economic literature reports that an ecoroof can provide these economic benefits, however, data are unavailable at this
time that would allow calculating a dollar amount for these benefits for an ecoroof in Portland.
In Virginia, a similar type of study was recently completed. To determine the financial impact of
implementing new stormwater regulations, estimated additional costs were evaluated for a
scenario of changing the stormwater management requirements to a proposed more stringent
3-86
Chapter 3. Urban and Suburban
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
level (at the time, 0.28 Ib/P/yr statewide; with a 10 percent reduction for redevelopment from
previously developed site) with an emphasis on volume reduction. The report notes the
environmental benefits of the proposed actions and the potential improvements in compliance
options and effectiveness afforded by accounting for runoff reduction in loading reductions. The
study concludes that while the incremental cost of the proposed regulations could not be
estimated, new costs would be incurred on land development activities. Program administration
costs were also noted as increasing, partially because of anticipated increases in tracking and in
ensuring compliance with distributed infiltration systems, which, although smaller individually,
would create a larger total number of practices requiring compliance tracking (Stephenson and
Beamer2008).
Cost-Effectiveness Analysis
Two cities that have conducted cost-
effectiveness analyses on innovative and
LID practices compared to traditional
stormwater practices are Mecklenburg,
North Carolina, and New York City. Each
had different significantly different
situations to evaluate.
Charlotte-Mecklenburg Stormwater
Services is in a rapidly developing urban-
suburban area. It has high sediment loads
to the drinking water reservoir caused by
the excess volume of urban runoff from
development eroding local streams
(Figure 3-19). Traditional stormwater
management practices have not been
adequate to prevent degradation. After a
comprehensive watershed planning effort,
the analyses demonstrated that LID
policies should be implemented for
development and that watershed retrofits
were needed to protect the drinking water
reservoir. The program focuses on in-
stream restoration, upland BMP retrofits,
and reforestation. Stream restoration was
found to be the most cost-effective retrofit
on a dollar-per-pound-of-sediment-saved
Source: McDowell Creek Watershed Masterplan, Charlotte-
Meckenburg Stormwater Services 2006
Figure 3-19. Sediment entering Mountain Island
Lake from McDowell Creek Cove.
Chapter 3. Urban and Suburban
3-87
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
basis, and extended detention was least the cost-effective means for sediment control retrofit in
the watershed (Charlotte-Mecklenburg Water Services, McDowell Creek Retrofit and
Restoration Master Plan at
http://www.charmeck.org/Departments/StormWater/Proiects/McDowell+Creek.htm).
New York City, like many older cities, has CSOs that routinely contaminate surface waters.
Conventional solutions include constructing deep tunnels to store the excess stormwater-
sewage mix. The high cost of the tunnels prompted the city to evaluate the cost-effectiveness of
other solutions. The city determined that it was more cost-effective on a dollar-per-gallon-saved
basis to implement new development standards, to require retrofits on building undergoing roof
replacements to detain stormwater, and to implement LID retrofits such as green streets, than to
rely on tunnel construction only. (PlaNYC, Sustainable Stormwater Management Plan, 2008
http://www.nvc.gov/html/planyc2030/html/stormwater/stormwater.shtml). The analysis does not
consider the amenity benefits to the community, as was conducted in the Philadelphia analysis
(Table 3-24).
One of the newer practices New York City found to be most promising is rooftop detention, or
blue roofs. Rooftop detention can serve as a first step in a treatment train for peak shaving, or
for storage for later use in irrigation, and so on. Cost observations were reported as follows:
Rooftop detention, one of the measures most likely to be used to comply with the
performance standard has low incremental costs. Compared to average costs of $18 per
square foot for a typical four-ply roof, the costs of a blue roof are only $4 per square foot
more. We assumed no additional maintenance costs above those incurred for a standard
roof. When we consider lifecycle costs, the economics improve further, because the
thicker membrane of blue roofs mean that they last longer than standard roofs; the
warranty provided by manufacturers is 20 years, compared to 10 to 15 years for standard
roofs. With approximate construction costs of $300 per square foot for new buildings, the
cost of this strategy is little more than 1 percent of construction costs.
Source: The City of New York, PlaNYC, Sustainable Stormwater Management Plan 2008, p. 52.
The cost-effectiveness findings of these two communities are shown in Tables 3-22 and 3-23.
3-88 Chapter 3. Urban and Suburban
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
Table 3-22. Cost-effectiveness analysis of stormwater management practices is used
to target the most cost-effective retrofit approach to reducing sediment loading to the
drinking water reservoir in the McDowell Creek Watershed in Charlotte-Mecklenburg,
North Carolina
Management practice
Major system stream restoration/enhancement
Minor system stream restoration/enhancement
Sand filter
Wet pond
Wetland
Rain garden
Extended detention
Vegetated swale
Filter strip
Pond retrofit
$ Per Ib of sediment saved
$1.02
$0.60
$24.43
$35.15
$50.33
$19.55
$69.60
$3.89
$6.23
$1.88
Table 3-23. New York City's cost-effectiveness analysis demonstrates the cost-effectiveness of
storage per gallon of runoff for new development standards, standards for existing building
(during roof replacement), and LID retrofits compared to traditional CSO mitigation using tunnels.
LID practices were among those with lower cost than traditional storage techniques.
Source control strategy
Performance Standards for New Development
Performance Standards for Existing Buildings (plus
preceding strategy)
Low- and Medium-Density Residential Controls (plus
preceding strategies)
Greenstreets(plus preceding strategies)
Sidewalk standards (plus preceding strategies)
Road reconstruction standards (plus preceding
strategies)
50% Right of way retrofits (plus preceding strategies)
Grey infrastructure reference case
Potential future CSO detention facilities
Cumulative
runoff capture*
(million
gallons)
1,174
2,838
3,954
4,178
8,400
9,868
24,092
Total CSO
reduction
2,266
Cumulative
PV cost
(2010-2030)
(millions)
$105
$416
$625
$676
$1,704
$2,123
$19,360
Total cost
$2,337
Cumulative
cost per
gallon
$0.09
$0.15
$0.16
$0.16
$0.20
$0.22
$0.80
Cost per
gallon
$1.03
Notes:
* Cumulative runoff capture with the source control scenarios refers to gallons of stormwater runoff that can be retained or
detained in those source controls. The city has not yet established the exact relationship between these quantities and the
corresponding reduction in CSOs.
PV = Present Value
Source: PlaNYC - Sustainable Stormwater Management Plan, 2008,
http://www.nvc.aov/html/planvc2030/html/stormwater/stormwater.shtml)
Chapter 3. Urban and Suburban
3-89
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
Locally evaluated benefits: Philadelphia. A broad range of societal benefits—and estimates
of the monetary value associated with these benefits—are described in Philadelphia Water
Department's (PWD's) A Triple Bottom Line Assessment of Traditional and Green Infrastructure,
Options for Controlling CSO Events in Philadelphia's Watersheds Final Report, 2009. The
categories of benefit accrual resulting from using green infrastructure stormwater management
approaches are the following:
• Recreational use and values
• Property values, as enhanced by the LID options
• Heat stress and related premature fatalities avoided
• Water quality and aquatic habitat enhancements and values
• Wetland enhancement and creation
• Poverty reduction benefits of local green infrastructure jobs
• Energy usage and related changes in carbon and other emissions
• Air quality pollutant removal from added vegetation
Table 3-24 shows the benefits (and external costs) Philadelphia estimated for a 40-year period
of two of the options compared for CSO solutions:
• A 50 percent LID and 50 percent conventional (tunnel) option
• An option consisting solely of conventional (tunnel) approaches
The 50 percent LID, or green infrastructure option, is a scenario in which 50 percent of the
impervious surface in the CSO area is managed through green infrastructure and the remainder
through conventional storage tunnels. The 30' Tunnel option represents a scenario where large
tunnels would be used to manage the CSO. Philadelphia selected the options for analysis
purposes, and they do not represent implementation decisions by the city. The table
demonstrates the value of the ancillary benefits of using green infrastructure for CSO mitigation
compared to the lack of ancillary benefits of traditional CSO management. Environmental
performance of the two options is not estimated to be completely equivalent, which should be
taken into consideration in fully comparing options.
Implementing those types of controls would be incremental over a development horizon time
frame. Additional information on Philadelphia's program is provided in Section 4.
The cost estimates for construction and maintenance are in the Long-Term Control Plan at
http://www.phillywatersheds.org/ltcpu/.
3-90 Chapter 3. Urban and Suburban
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
Table 3-24. Summary of Philadelphia's analysis of green infrastructure to help mitigate CSOs: Present
value benefits of two options studied (Cumulative estimated through 2049 in 2009 million USD)
Benefit categories
Increased recreational opportunities
Improved aesthetics property value (50%)
Reduction in heat stress mortality
Water quality aquatic habitat enhancement
Wetland services
Social costs avoided by green collar jobs
Air quality improvement from trees
Energy savings usage
Reduced (increased) damage form SO2 and NOx emissions
Reduced (increased) damage from CO2 emissions
Disruption costs from construction and maintenance
Total
50% LID option
$524.5
$574.7
$1,057.6
$336.4
$1.6
$124.9
$131.0
$33.7
$46.3
$21.2
$(5.6)
$2,846.4
30' Tunnel
option3
$189.0
$(2.5)
$(45.2)
$(5.9)
$(13.4)
$122.0
Source: Summary of Triple Bottom Line Analysis, City of Philadelphia Long-Term Control Plan,
http://www.phillvwatersheds.org/ltcpu/Vol02 TBL.pdf
a. 28' tunnel option in Delaware River watershed
Regionally evaluated benefits: Sun Valley Watershed, Los Angeles County. The Sun
Valley watershed area of Los Angeles County experienced frequent flash flooding and a
conventional storm drain pipe solution was proposed. However, the community initiated a
process that prompted Los Angeles County to review more environmentally sound alternatives,
particularly in light of the areas (1) severe drought conditions; (2) decreasing groundwater
supplies; (3) high cost of the current practice of importing most of the region's water from
sources including out-of-state; and (4) impaired water resources from urban stormwater runoff.
The underlying regional stormwater management issues of rainwater loss, high demand, and
the resulting high-energy-use water supply infrastructure is described in A Clear Blue Future:
How Greening California Cities Can Address Water Resources and Climate Challenges in the
21st Century (NRDC 2008).
To select the best-value alternative, categories of benefits were developed. Various methods
were used to quantify the benefits including using avoided costs, willingness to pay values from
the literature, and valuation pricing (e.g. increases in property values). Project benefits (and
costs) were evaluated over a 50-year horizon. The benefits evaluated included the following:
• Flood Control—Avoided cost of facilities needed to provide comparable local and
downstream flood protection
Chapter 3. Urban and Suburban
3-91
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
• Water Quality Improvements—Avoided costs associated with removal of bacteria and
other listed pollutants from waters that contribute to the Los Angeles River
• Water Conservation—Cost savings associated with using stormwater for groundwater
recharge and water supply augmentation compared to purchasing imported water
• Energy—Cost savings associated the reduced energy consumption from planting shade
trees and the decreased amount of energy used to pump imported water into the Los
Angeles Basin under each alternative
• Air Quality Improvements—Absorption of pollutants by the tree canopy and reduced
emissions from power plants from decreased energy consumption
• Ecosystem Restoration—Increased habitat and open space
• Recreation—Value of increased parkland and recreation for the area
• Property Values—Impact of project components on nearby property values
The costs of each alternative were monetized, including capital facilities costs, land acquisition
costs, and expected O&M costs. The results of the benefit-cost analysis are summarized in
Table 3-25, which shows the benefit-cost ratio for each alternative. The ratios use the present
value of total project costs and benefits over the 50-year evaluation period. As a result of the
analysis, an LID and infiltration alternative was selected and successfully implemented instead
of the piped solution. The Los Angeles County Department of Public Works is now widely using
this type of project analysis (Los Angeles County Department of Public Works 2004:
http://www.sunvalleywatershed.org/ceqa docs/plan.asp).
Table 3-25. Benefit/Cost ratio analysis for Sun Valley stormwater management alternatives shows
that the storm drain pipe alternative provided less long-term value than LID/green infrastructure
alternatives in a 50-year net present value analysis
Alternative
Present value of total
benefits (millions
$2002 USD)
Present value of total
costs (millions $2002
USD)
Benefit-cost ratio
Storm drain
pipe
alternative
$73.44
$74.46
0.99
Alternative 1
infiltration
$270.47
$230.40
1.17
Alternative 2
water
conservation
$295.39
$171.58
1.72
Alternative 3
stormwater
reuse
$274.93
$297.90
0.92
Alternative 4
urban storm
protection
$239.95
$206.61
1.16
Note: A Benefit-Cost ratio greater than one indicates more benefits than cost.
3-92
Chapter 3. Urban and Suburban
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
2.10.3 Costs of Individual Practices
Given the considerations described above, it is clear that comparing the costs of individual LID
practices to each other, or just to other stormwater management practices, is not the best way
to fully evaluate the costs of LID practices or to convey the information on the economies that
can realized by efficient development planning. In addition to not accounting for these benefits,
just stating practice cost does not show how costs can be optimized by integrating LID features
into the landscape, or by selecting rooftop-to-stream incremental features to filter, treat, retain,
capture and use runoff. A green roof might appear a relatively high cost practice, but in a
densely urbanized area it could be the most economical solution for stormwater management,
and given the potential benefits shown in the Portland BES, Oregon, study (Figure 3-2), could
be a worthwhile investment in the long term depending on the ultimate use for the building.
Issues that should be considered when estimating capital costs include the following:
• Because LID practices are relatively new, few examples of comprehensive, full-scale
project costs are readily available, and costs that are available often represent higher
pilot-scale or demonstration project costs.
• Limited literature values for costs often do not provide complete information needed, such as
design/construction/startup information, or level of water quality treatment to be provided.
• Costs are highly site specific and are influenced by contractors' familiarity with the
practices, and therefore vary considerably.
• LID practices are constructed primarily by using conventional construction techniques
that can be readily estimated using local contractor quotes and industry guides such as
Reed Construction Data (R.S. Means), as is done for conventional construction.
Issues that should be considered when evaluating O&M costs include the following:
• O&M will account for much of the ownership cost, so managers should consider the
expected reliability and ease of maintenance when selecting a practice, not just the
capital cost.
• Utilities maintenance staff are trained in management of conventional drainage systems,
and changes might be needed for institutional programs for O&M to result in more cost-
effective O&M that has been reported for maintaining pilot facilities.
• O&M costs attributed to LID practices were found to primarily be for aesthetics (WERF
2005), although more information is needed to determine what role aesthetics play in
O&M costs reported. Many of the activities that would have occurred in regular
nonfunctional landscaping (weed control, litter removal) are reported as LID
maintenance. That can make it difficult to determine how much of the reported cost is
actually an additional cost incurred to ensure that the practice functions.
Chapter 3. Urban and Suburban 3-93
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
• O&M costs for maintaining bioretention might be similar to the current maintenance
costs for nonfunctional landscaping, in fact, they could be lower because bioretention
would receive more rainwater and require less watering with potable water.
A wide range of potential cost outcomes for both capital and O&M are reported, such as
• Cost savings using LID is widely reported from minimizing conventional piped
infrastructure and ponds, and simply using land and landscaping functionally.
• Higher cost can occur in dense, urban environments where cistern systems or green
roofs might be costly, but necessary because of land limitations.
• Limited cost savings or additional costs could be incurred if the local codes require
installing minimum-sized piped systems regardless of LID design. This could be for flood
control or other site-specific issues.
Estimates of stormwater management practice costs have been prepared by several entities
and reflect the variability that is inherent in site-specific design and construction.
The determination of the most cost-effective practice is site-specific, depending on the
availability of land, the local costs of labor and materials, and level of treatment required. The
costs of individual practices are provided in the practice Fact Sheets in Appendix 1. General
cost ranges and cost estimating approaches for LID and other stormwater management
practices have been documented in the literature and are repeated here. References are
provided in Table 3-26.
Table 3-26. Sources of general cost ranges and cost estimating approaches for LID practices
USEPA. 2004a. Stormwater Besf Management Practices Design Guide, Office of Research and
Development, EPA/600/R-04/121, Volumes 1-3 (121, 121A, 121B).
USEPA. 2004b. The Use of Best Management Practices (BMPs) in Urban Watersheds, Office of
Research and Development, EPA/600/R-04/184.
CWP. 2007. Urban Subwatershed Restoration Manual Series (http://www.cwp.org/Store/usrm.htm')
Water Environment Research Foundation. 2005b. Performance and Whole-Life Costs of Sustainable
Urban Drainage Systems, 01-CTS-21T
Water Environment Research Foundation. 2009. Decentralized Stormwater Controls for Urban Retrofit
and Combined Sewer Overflow Reduction, Phase II.
Wiess, Peter T., et al. 2005. The Cost and Effectiveness of Stormwater Management Practices,
Minnesota Department of Transportation, MN/RC - 2005-23.
However, to supplement existing information sources, some recent examples are summarized
in Table 3-27, and some specific recent cost information from those sources is provided here.
3-94 Chapter 3. Urban and Suburban
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
Table 3-27. Sources of recent cost information for LID practices—capital, O&M, life cycle
Source
USEPA. Reducing Stormwater Costs through Low-Impact
Development, Publication Number EPA 841 -F-07-006
USEPA 201 Od.
ECONorthwest. The Economics of Low-Impact
Development: A Literature Review, November 2007
Natural Resources Defense Council. Rooftops to Rivers:
Green Strategies for Controlling Stormwater and Combined
Sewer Overflows; NRDC 2006.
www.nrdc.org/water/pollution/rooftops/contents.asp
Fact Sheets in Appendix 1
City of Portland, Oregon, Bureau of Environmental
Services, Sustainable Stormwater Management Pages,
www.portlandonline.com/bes/index.cfm?c=34598
Water Environment Research Foundation. WERF Cost
Tool, 2009. Free spreadsheet tool developed as part of
Performance and Whole Life Cost of Best Management
Practices and Sustainable Urban Drainage Systems (2005).
Water Environment Research Foundation.
www.werf.org/AM/Template. cfm?Section=Stormwater3
City of Philadelphia. Long Term Control Plan Update,
Supplemental Documentation, Volume 3, Basis of Cost
Opinions, September 2009;
www.phillywatersheds.org/ltcpu/Vol03 Cost.pdf
North Carolina Coastal Federation. Low Impact
Development Pilot Study to Reduce Fecal Coliform into
Core Sound, Final Report, Sea Grant Project Number:
07-EP-03, November 2008
North Carolina State University (NCSU). Bill Hunt et al.
Evaluating LID for a Engineering Development in the
Lockwood Folly Watershed, North Carolina.
www.nhcgov.com/AgnAndDpt/PLNG/Documents/Brunswick
LID.pdf
New York City, Plan NYC, Appendix C, 2008,
www.nvc.gov/html/planvc2030/html/stormwater/stormwater.
shtml
City of Portland, Bureau of Environmental Services. Cost
Benefit Evaluation of Ecoroofs 2008.
www.portlandonline.com/bes/index.cfm?c=5081 8&a=261 053
PWD. A Triple Bottom Line Assessment of Traditional and
Green Infrastructure. Options for Controlling CSO Events in
Philadelphia's Watersheds Final Report, 2009.
www.phillvwatersheds.org/ltcpu/Vol02 TBL.pdf
Key items
Savings of 15% to 80% found for LID
subdivisions compared to conventional
subdivision drainage practices.
Case studies of LID costs and economic
benefits
Policy guide for decision makers for LID;
nine case studies of successfully used
green technigues.
Cost considerations associated with each
practice presented.
Extensive examples of green roofs and
green streets, as well as other sustainable
Stormwater practices.
Provides estimates based on literature
values. Intended for modification as
needed for user project data. Calculates
life cycle cost. Contains literature review
by practice.
Full range of LID costs for new,
redevelopment, and retrofit. O&M costs.
Anticipated cost reduction as practices
become more widely used. Retrofit focus.
Detailed costs for rain gardens, cisterns,
conservation landscaping and other LID
practices. Six implemented and 9
planned.
Demonstrates the cost savings achievable
using LID in place of conventional
Stormwater treatment.
For controls that are high-priority for
retrofit.
Quantifies the benefits to owner and
public of installing green roofs
LID-based, green infrastructure
approaches provide a wide array of
important environmental and social
benefits to the community, and that these
benefits are not generally provided by the
more traditional alternatives.
Chapter 3. Urban and Suburban
3-95
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
Sources of cost data for urban stormwater retrofits, especially roadway retrofits, include the
following:
• Portland, Oregon's, Bureau of Environmental Services. For example, Portland notes in
its description of its Tabor-to-the-River watershed green streets retrofit that resolves the
drainage problems it faces using only pipe solutions would have cost an estimated
$144 million, while adding sustainable, green stormwater management systems reduced
the estimated cost to $86 million and enhanced water quality and watershed health
(www.portlandonline.com/bes/index. cfm?c=50500&a=230066).
• Seattle, Washington's, utilities department, Seattle Public Utilities (SPU), has developed
and adopted a green street design and retrofit approach it calls Natural Drainage Systems
(NDS), started with the completion of the successful SEA Street project in 2001.
(www.seattle.gov/util/About SPU/Drainage & Sewer Svstem/GreenStormwaterlnfrastr
ucture/NaturalDrainageProjects/index.htm). As part of the program's adoption, SPU
conducted a benefit/cost comparison in 2003 between traditional designs and the NDS
design. A summary is provided in Figure 3-20.
Local governments in the Mid-Atlantic area with cost data include the following:
• Philadelphia, Pennsylvania,
• Montgomery County, Maryland
• North Carolina Division of Soil and Water's Community Conservation Assistance
Program (CCAP)
Philadelphia Water Department (PWD). PWD conducted a cost analysis of wet-weather
management approaches as part of its effort to screen and compare green-to-gray technologies
in its Long-Term Control Plan Update (LTCPU). The costs for several of those technologies are
provided here; for additional information and assumptions, see the LTCPU. In general, these
are planning-level estimates, expected to fall in the range of -30 percent to +50 percent for the
Philadelphia area.
3-96 Chapter 3. Urban and Suburban
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
Seattle Public Utilities — Natural Drainage System Program
Problem Statement: Seattle's rece
effects of urban stormwater runoff.
Traditional methods of stormwater
effects of current and future develc
Natural Drainage Systems (NDS
environmental protection for receiv
ving waters and aquatic life have been
Increasing volumes of runoff also cause
management and street design have pr
pment on receiving waters.
is an alternative stormwater managem
inq waters at a lower cost than tradition
o NDS targets areas of the city draining to creek watersheds that do no
improvements.
o NDS design is based on technology that emphasizes infiltration and c
reduce the total volume of runoff reaching creek systems.
o The goal of NDS is to more closely match the hydrologic function of r
development, thereby creating stable creek systems and clean water
o NDS designs cost less than traditional drainage and street designs.
significantly impaire
; flooding of roadwj
oven to be ineffecti
snt approach that d
al street and draina
t have formal drain
decentralized treatn
atural forests that e
d by the negative
jys and property.
ye at countering the
elivers hiqher levels of
ge improvements.
age or street
nent of stormwater to
existed before
Cost analysis of natural vs. traditional drainage systems meeting NDS stormwater goals
Street type
Community
Benefits
Ecological
Benefits
% impervious
area
Cost per
block (330
linear feet)
Local street
SEA Street
• One sidewalk
per block
• New street
paving
• Traffic
calming
• High
neighborhood
aesthetic
• High
protection for
aquatic biota
• Mimics
natural
process
• Bio-remediate
pollutants
35%
$325,000
Local street
Traditional
• Two sidewalks
per block
• New street
paving
• No traffic
calming
• No
neighborhood
aesthetic
• High protection
flooding
• Some water
quality
35%
$425,000
Collector street
Cascade
• No street
improvement
• Moderate
neighborhood
aesthetic
• High water
quality
protection
• Some flood
protection
35%
$285,000
Collector street
Traditional
• No street
improvement
• No
neighborhood
aesthetic
• High
protection
from flooding
• Some water
quality
35%
$520,400
Broadview Green
Grid 15 block area
• Both SEA Street
and Cascade
types
• One sidewalk per
block
• New paving
• High
neighborhood
aesthetic
• High water quality
& aquatic biota
protection
• Some flood
protection
• Excellent
monitoring
opportunity
35%
Average per block:
$280,000
Source: www.seattle.qov/util/About SPU/Drainaqe & Sewer Svstem/GreenStormwaterlnfrastructure/index.htm
Figure 3-20. Comparison by SPU shows lower construction costs for NDS than traditional street
design.
These costs were used as the basis for estimating the cost-to-benefits comparison of PWD's
report A Triple Bottom Line Assessment of Traditional and Green Infrastructure Options for
Controlling CSO Events in Philadelphia's Watersheds. The report indicates that the benefits
from green infrastructure stormwater management are significant; those findings on benefit
Chapter 3. Urban and Suburban
3-97
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
valuations are applicable even to non-CSO communities. To compare the costs of traditional
versus green infrastructure, PWD assessed the capital, O&M, and life cycle costs for several
stormwater management practices. It is important to note that the estimated costs were for
facilities that would theoretically meet Philadelphia's stormwater ordinance, shown in
Figure 3-21, to manage the first inch of runoff from directly connected impervious area, by
infiltration possible, unless a waiver is obtained.
The Water Quality requirement stipulates management of the first one inch of runoff from all Directly
Connected Impervious Areas (DCIA) within the limits of earth disturbance. The Water Quality requirement is
established to (1) recharge the groundwater table and increase stream base flows; (2) restore more natural
site hydrology; (3) reduce pollution in runoff; and (4) reduce combined sewer overflows (CSO) from the
city's combined sewer systems. The requirement is similar to water quality requirements in surrounding
states and in other major cities.
• The requirement must be met by infiltrating the water quality volume unless infiltration is determined to
be infeasible (because of contamination, high groundwater table, shallow bed rock, poor infiltration
rates, etc.) or where it can be demonstrated that infiltration would cause property or environmental
damage.
• A waiver from the infiltration requirement must be submitted and approved if infiltration is not feasible...
(continues)
Source: Philadelphia's Stormwater Manual; http://www.phillvriverinfo.org/WICLibrarv/chapter%201.pdf
Figure 3-21. Philadelphia Stormwater Manual v2.0—Section 1.1.1 Stormwater Ordinance and
Regulations
Cost estimate ranges for capital construction from PWD's Long-Term Control Plan for planning
purposes are provided in Table 3-28 for redevelopment and for retrofit.
In addition to capital cost, PWD estimates the cost decrease that can occur as LID practices
become more of a standard practice. In the LTCPU, PWD addresses many of the
considerations in evaluating costs, including O&M schedules and costs and replacement costs.
PWD LTCPU estimates that costs will decrease for the following reasons (PWD 2009):
• Improved site designs will result as designers learn to incorporate the new stormwater
requirements into designs from the beginning. Now, such features are added to a site
plan as an afterthought, resulting in higher design costs. Leaving more functional open
space in the site design for stormwater management is assumed to occur over time, and
designers will learn how to work with the expected site conditions.
3-98 Chapter 3. Urban and Suburban
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
Table 3-28. Summary of direct construction cost estimates from PWD's Long-Term Control Plan
Supplemental Documentation, Volume 3
Control
Bioretention
Subsurface
Infiltration
Green Roof
Porous
Pavement
Street Trees
Type
Retrofit
Redevelopment
Retrofit
Redevelopment
Retrofit
Redevelopment
Retrofit
Redevelopment
Retrofit
Redevelopment
Minimum cost
($ / impervious
acre)
$65,000
$44,000
$65,000
$44,000
$430,000
$200,000
$65,000
$44,000
$18,000
$15,000
Median cost
($/im pervious
acre)
$120,000
$90,000
$120,000
$90,000
$500,000
$250,000
$160,000
$110,000
$18,000
$15,000
Mean cost
($ / impervious
acre)
$160,000
$110,000
$160,000
$110,000
$500,000
$250,000
$160,000
$110,000
$18,000
$15,000
Max cost
($ / impervious
acre)
$410,000
$200,000
$410,000
$200,000
$570,000
$290,000
$410,000
$200,000
$18,000
$15,000
Source: Philadelphia LTCP; Engineering News-Record Construction Cost Index 7966; R.S. Mean 115.2
*From Philadelphia LTCP: Other cities have been experiencing costs in the range of $7-$16 per square foot ($305,000-
$700,000 per impervious acre), with atypical range of $10-14 per square foot ($435,000-$610,000 per impervious acre).
A recent green roof at Temple-Ambler campus was approximately $11 per square foot ($480,000 per impervious acre).
The least expensive green roofs in Chicago, which has the largest-scale program in the U.S., are on the order of $6-7 per
square foot ($285,000 per impervious acre), and this could be a reasonable estimate of what can be achieved in the future
with a large-scale program in Philadelphia.
• Lower material costs are expected over time as the practices become more standard.
The materials that are at a premium now because they are specialty items will become
routine. For example, PWD estimates that in the future, permeable pavement costs will
be comparable to traditional pavement costs.
• Reduced design costs are expected as more designers become familiar with LID
practices. PWD estimates that designs for LID projects will be on par with more standard
designs.
• Reduced perception of risk will result in a lower contingency being applied to cost
estimates.
The ranges of cost reduction expected by PWD over time from improved site design and lower
material costs is approximately 20 percent up to about 25 percent.
Montgomery County, Maryland, LID Green Street Programs. Green street projects have
been implemented for the past several years in Portland, Oregon, Seattle, Washington, and
other locations. Montgomery County, Maryland, has undertaken several green streets projects,
and recently compared the costs of its projects, both estimated and completed, with reported
Chapter 3. Urban and Suburban
3-99
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
costs from other jurisdictions, as well as could be interpreted from the literature information
provided. There is limited data available to date, and many factors contribute to the differences
in costs reported, so this data might not be widely applicable. Table 3-29 presents a recent
summary of the Montgomery County evaluation, with information added from Portland on its
estimates.
Table 3-29. Summary of green streets cost evaluation
Estimated
level of
WQ
control
Total DA
(acres)
Cost per acre DA
(in $1, OOOs)
design
construction
Cost per sf BMP SA
(in $/sf)
design
construction
Cost per impervious
acre DA
(in $1 ,000s)
design
construction
Bioretention retrofit projects
Montgomery
County
Portland
(Areas reported
as impervious
only)
Prince George's
County
100%
100%
100%
66%
86%
1.1a
0.1 7b
0.21C
13.4d
1.5e
$17
$41
$10
$14
$72
$112
$214
$79
$104
$92
$17
$26
$8
$19
$99
$113
$136
$29
$139
$126
$20
$41
$10
$32
$217
$131
$214
$79
$233
$276
Swales and filter strip retrofit projects
Montgomery
County
Caltrans
Swales
Caltrans Filter
Strips
Burnsville, MN
(less
urbanized)
16% to 50%
56%
100%
NR
1.1 to3.7f
0.20 to
2.4gj
0.49 to
2.42hJ
5.3j
$33 to $75
NR
NR
$12
$26 to $84
$31 to $121
$23 to $120
$24
$35 to $86
NR
NR
NR
$39 to $44
$12 to $58
$12 to $43
NR
$96 to
$128
NR
NR
NR
$40 to $143
$35 to $128
$35 to $128
NR
Source: Montgomery County, Maryland, and Portland, Oregon
Notes:
NR = Not Reported; DA = Drainage Area; SA = Surface Area; sf = square foot; Estimated Level of Control =
a. Dennis Ave. Health Center
b. 12th & Montgomery Ave.; Portland, OR, Report - only planter & pavers;
ttp://asla.org/awards/2006/06winners/341.html
c. Green-Siskiyou, OR - curb planters, no subdrain, assume total DA (total impervious DA in report);
http://www.asla.org/awards/2007/07winners/506 nna.html
d. Route 201 Gateway - roadway median retrofit
e. U.S. Rt. 1 at I-95 Interchange
f. Various projects, combination of completed costs and costs estimated for projects yet to be built
g. Various 2004 projects; include factors that increased the cost for dense urban retrofit (traffic control, etc.)
h. Various 2004 projects; include factors that increased the cost for dense urban retrofit (traffic control, etc.)
i. BMP Retrofit Pilot Program, Final Report, Report ID CTSW- RT - 01 - 050, California Department of Transportation, January
2004
j. Roadside swales and rain gardens; suburban community retrofits
3-100
Chapter 3. Urban and Suburban
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
Coastal North Carolina, Community Conservation Assistance Program (CCAP). Striving to
protect its shellfish resources, North Carolina has encouraged LID since 1986. As a result,
North Carolina has implemented a cost-share program to help start the adoption of new LID
technologies. They developed cost information that they use in the CCAP to estimate cost-
sharing amounts. Table 3-30 provides a summary costs for coastal North Carolina for 2009.
Table 3-30. LID costs used by the North Carolina Division of Water Quality's Community Cost Share
Program
BMP
Abandoned well closure
Backyard rain garden
Backyard wetland
Cisterns
Critical area planting
Diversion
Components
Bioretention excavation
Bioretention soil amendment -sand
Bioretention mulch
Bioretention plants (installed)
Wetland excavation
Wetland plants (installed)
Wetland outlet structure
Cistern 250-1 ,000 gallons installed
Cistern 1 ,000-3,000 galons installed
Cistern 3,000 gallons installed
Accessories package
Cistern foundation
Concrete pad for cistern
Shipping charge
Grading - minimum
Grading - light, 1"- 3" avg
Grading - medium, 3" - 6" avg
Grading - heavy, 6" - 9" avg
Grading - extra heavy, 9" - 12" avg
Grading - maximum heavy, more than 12" avg
Vegetation (grass) - minimum
Vegetation (grass)
Vegetation (trees/shrubs)
Vegetation - mulch, netting
Vegetation - mulch, small grain straw
Matting - excelsior, installed
Excavation
Vegetation (grass)
Filter cloth-geotextile fabric
Filter cloth-pins, metal anchor
Vegetation - mulch, netting
Vegetation - mulch, small grain straw
Matting - excelsior, installed
Unit type
Each
SqFt
SqFt
SqFt
SqFt
SqFt
SqFt
SqFt
SqFt
Each
Each
Gallon
Gallon
Gallon
Each
SqFt
SqFt
Each
SqFt
Job
100 SqFt
100 SqFt
100 SqFt
100 SqFt
100 SqFt
Job
100 SqFt
SqFt
100 SqFt
100 SqFt
SqYd
Feet
SqFt
100 SqFt
SqYd
Each
100 SqFt
100 SqFt
SqYd
All areas unit cost
$5.00
$0.50
$0.75
$1.50
$5.50
$2.30
$50.00
$1.75
$1.00
$700.00
$1.40
$3.60
$25.00
$3.90
$4.82
$5.74
$6.66
$7.58
$15.00
$0.75
$1.28
$0.95
$5.00
$0.75
$2.25
$2.00
$1.26
$0.95
Chapter 3. Urban and Suburban
3-101
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
Example Cost Comparison of LID Parking Lot and Conventional Parking Lot. When
evaluating the costs of LID, it is important to compare to the costs of alternative stormwater
management. The economies of subdivision development with LID practices have been
documented (USEPA 2007). As an example, Table 3-31 presents a detailed breakdown of a
cost comparison for two parking areas estimated for a project in Massachusetts, indicating that
the LID construction cost was not higher than conventional costs. For this project, design costs
were reported as higher because it was a relatively new type of design, but lower maintenance
costs were anticipated.
Table 3-31. Comparison of conventional design vs. bioretention in two parking areas in Amesbury,
Massachusetts
Landscape
j£
i
0)
*j
w
Item
Loam (4" depth) (CY)
Bioretention soil mix
(24" depth) (CY)
Seed (SY)
Composted, double
shredded hardwood
mulch (3" depth) (CY)
Trees (EA)
Shrubs (EA)
Perennials and
grasses (EA)
HOPE Drain pipe (12"
dia) (LF)
Catch Basins (EA)
Water Quality Units
(Stormceptor STC
900) (EA)
Curb (Extruded
Concrete) Straight (LF)
Curb (Extruded
Concrete) Radius (LF)
Wheel Stops (EA)
Drain Manholes (EA)
Earthwork (CY)
Pipe Bedding (CY)
Bioretention Area 1
Island = 51, 155 SF
(4,867 SF landscape)
Quantity
LID
NA
360.5
240
25
18
61
1450
NA
NA
NA
NA
NA
43
NA
NA
NA
Standard
59.6
NA
541
0
18
30
0
55.4
2
1
506.8
45.7
NA
NA
183
15.3
Unit
cost
$40
$40
$4
$28
$518
$32
$2
total
$12
$3,075
$8,000
$6
$8
$66
$3,325
$5
$2
total
Total cost
LID
NA
$14,421
$960
$700
$9,315
$1 ,922
$2,900
$30,217
NA
NA
NA
NA
NA
$2,838
NA
NA
NA
$2,838
Standard
$2,384
NA
$2,164
$0
$9,315
$945
$0
$14,808
$648
$6,150
$8,000
$2,914
$356
NA
NA
$860
$36
$18,964
Bioretention Area 2
Adjacent to clubhouse = 77,90 SF
(19,584 SF landscape)
Quantity
LID
179
363
1360.8
68
45
216
2068
NA
NA
NA
NA
NA
49
NA
NA
NA
Standard
239.4
NA
1941
20
45
108
0
148
4
1
655.5
78.5
NA
1
493
41.1
Unit
cost
$40
$40
$4
$28
$518
$32
$2
total
$12
$3,075
$8,000
$6
$8
$66
$3,325
$5
$2
total
Total cost
LID
$7,160
$14,520
$5,443
$1 ,904
$23,288
$6,804
$4,136
$63,255
NA
NA
NA
NA
NA
$3,234
NA
NA
NA
$3,234
Standard
$9,576
NA
$7,764
$560
$23,288
$3,402
$0
$44,590
$1,732
$12,300
$8,000
$3,769
$612
NA
$3,325
$2,317
$96
$32,151
Bioretention Area 1
Bioretention Area 2
total
$33,055
$33,772
total $66,489
$76,740
Source: Eisenburg, Bethany, Design, Engineering, Installation, and O&M Considerations for Incorporating Stormwater Low Impact
Development (LID) in Urban, Suburban, Rural, and Brownfields Sites, American Society of Civil Engineers (ASCE), Low Impact
Development Conference Proceedings, 2008
3-102
Chapter 3. Urban and Suburban
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
3 Implementation Measures for Reducing
Pollutant Concentrations with Source Controls
and Treatment
Reduce pollutant concentrations by implementing source control measures and by
treatment practices as necessary to meet water quality goals
Stormwater quantity control, along with source and pollution prevention controls, has been
determined to be the most reliable means of achieving pollutant reduction and mitigating the
many adverse environmental effects of excess urban stormwater runoff (National Research
Council 2008). Many issues arise in the decision-making process of selecting stormwater
controls. This section addresses some of those considerations related to source-control practice
selection and stormwater treatment technologies.
This document does not address flood-control considerations. However, note that volume
control practices can contribute to flood protection by infiltrating, evapotranspiring, and reusing
precipitation that would otherwise contribute to floods. Although volume control is the most
important tool to reduce the loadings of urban runoff pollutants to the Chesapeake Bay, some
significant sources of pollutants are likely to require source control or treatment. They can
include areas with vehicles or other urban/commercial/industrial activity.
A primary consideration in selecting stormwater management practices is the regulatory policy
for the site and practice. Local, state, and federal regulations and policies apply, and managers
should research these before site design and practice selection. Additional general information
on how to choose among the many available stormwater runoff control practices is provided in
Decentralized Stormwater Controls for Urban Retrofit and Combined Sewer Overflow Reduction
(Weinstein etal. 2005).
Source Control/Pollution Prevention
Implementation Measures:
U-10. Identify the pollutants of concern (POCs) to help target the selection of
pollution prevention/source control that are most appropriate, for example,
nutrients and sediment.
U-ll. Implement pollution prevention/source control policies, i.e., nonstructural,
programmatic efforts as basic, routine land management practices to target
specific pollutants.
Chapter 3. Urban and Suburban 3-103
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
U-12. Require source control practices on:
• New and redevelopment site plans for commercial/industrial facilities
• Commercial/industrial facilities through development of a
— Stormwater Pollution Prevention Plan (SWPPP) where required for
regulated industrial facilities.
— Similar stormwater pollution prevention plans that may be required
by local authorities or should be prepared for facility management.
• Municipal facilities or other designated Municipal Separate Storm Sewer
System (MS4s) permittees through development of Pollution
Prevention/Good Housekeeping programs such as the Stormwater Phase
II Minimum Control Measures.
U-13. Develop and implement ongoing outreach programs aimed at behavior
change to prevent pollution and qcontrol it at its source. Methods for impact
and effectiveness evaluation should be incorporated into these outreach and
education programs.
U-14. Implement programs for disconnection of directly connected impervious
area, such as residential downspout disconnection programs.
U-15. Conduct inspections of commercial/industrial facilities to provide
compliance assistance or to ensure implementation of controls.
Runoff Treatment
Implementation Measures:
U-16. Identify the POCs to help target the type of treatment approaches that are
most appropriate
U-17. Select treatment practices based on applicability to the POCs
• Use practices to reduce runoff volume as the preferred and most reliable
approach to reducing pollutant loading to receiving waters
• Use treatment practices as needed if reduction of runoff is not feasible
• Base the selection of treatment practice on
— treatment effectiveness for the POC to ensure discharge quality
— long-term maintenance considerations to ensure continued adequate
maintenance and recognition of life-cycle costs
— site limitations to ensure appropriateness of practice to the site
— aesthetics and safety to ensure public acceptance
3-104 Chapter 3. Urban and Suburban
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
3.1 Source Control/Pollution Prevention
3.1.1 Identify Pollutants of Concern
Regulatory and Policy Drivers. POCs can be regulated by federal, state, or local requirements
and policies. For the Chesapeake Bay, critical POCs are evident in the Chesapeake Bay
Executive Order, which specifies that N, P, and sediment are POCs that must be controlled to
successfully protect and restore the Bay.
Other examples of the types of regulations or issues that can result in specific types of
pollutants being identified for reduction include the following:
• Narrative and numeric water quality standards at the federal, state, or local level.
• Specific National Pollutant Discharge Elimination System (NPDES) permit limitations.
• The Toxics Release Inventory makes available to the public annually collected data on
the storage, release, and transfer of certain toxic chemicals from industrial facilities.
Required under Emergency Planning and Community Right-to-Know Act, its primary
purpose is to inform communities and citizens of chemical hazards in their areas.
• TMDL requirements under the Clean Water Act section 303(d) for water quality limited
segments (www.epa.gov/owow/tmdl).
• States and local governments can develop watershed pollutant reduction goals, such as
the Watershed Implementation Plans being prepared under the Bay TMDL
(www.epa.gov/chesapeakebaytmdl/EnsuringResults. html?tab2=1).
• Other pollutants identified in studies evaluating urban runoff characteristics, such as
metals from brake pad dust, toxic organics, petroleum hydrocarbons, pesticides and
herbicides.
Predominant Land Uses. Specific land uses also contribute to the loading of certain pollutants.
Land use type is one predictive indicator for the type of pollutants and typical pollutant loading
that would be discharged during storm events. POCs and typical loadings from various land use
types can be assumed using modeled data in the literature, such as from the 1983 Nationwide
Urban Runoff Program (NURP) (see Table 3-32), or more recent sources. Models that can be
used to estimate loading from land use types are provided in Appendix 2 of this chapter.
Chapter 3. Urban and Suburban 3-105
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
Table 3-32. Median stormwater pollutant concentrations from NURP study by land use
Pollutant
BOD
COD
TSS
Total Pb
Total Cu
Total Zn
TKN
Nitrate + Nitrite
Total P
Soluble P
Units
mg/L
mg/L
mg/L
ljg/L
ug/L
ljg/L
ljg/L
ljg/L
ug/L
ug/L
Residential
Median
10
73
101
144
33
135
1,900
736
383
143
CV
0.41
0.55
0.96
0.75
0.99
0.84
0.73
0.83
0.69
0.46
Mixed
Median
7.8
65
67
114
27
154
1,288
558
263
56
CV
0.5
0.58
1.14
1.35
1.32
0.78
0.5
0.67
0.75
0.75
Commercial
Median
9.3
57
69
104
29
226
1,179
572
201
80
CV
0.31
0.39
0.85
0.68
0.81
1.07
0.43
0.48
0.67
0.71
Open space/
non-urban
Median
-
40
70
30
-
195
965
543
121
26
CV
-
0.78
2.92
1.52
-
0.66
1
0.91
1.66
2.11
Source: Nationwide Urban Runoff Program (USEPA 1983)
CV = Coefficient of variation = standard deviation/mean
More recent quantification of urban pollutants is summarized in the National Stormwater Quality
Database (NWQD) (Pitt et al. 2004). Tables 3-33 and 3-34 include excerpts from the summary
report to highlight pollutant concentrations from typical urban land uses. It is noted that the
NURP data and the NSQD data were collected using different protocols, as the NSQD data was
collected by MS4's under the NPDES program protocols, and NURP data was collected using
U.S. Geological Survey (USGS) protocols.
Table 3-33. Median concentration of typical stormwater pollutants from urban land uses
Land use
Residential
Mixed Residential
Commercial
Mixed Commercial
Industrial
Mixed Industrial
Institutional
Freeways
Mixed Freeways
Open Space
Mixed Open Space
TDS
(mg/L)
72
86
74
70
92
80
52.5
77.5
174
125
109
TSS
(mg/L)
49
68
42
54
78
82
17
99
81
48.5
83.5
BOD5
(mg/L)
9
7.6
11
9.25
9
7.2
8.5
8
7.4
5.4
6
COD
(mg/L)
55
42
60
60
60
40.4
50
100
48
42.1
34
NH3
(mg/L)
0.32
0.39
0.5
0.6
0.5
0.43
0.31
1.07
~
0.18
0.51
N02+N
03
(mg/L)
0.6
0.6
0.6
0.58
0.73
0.57
0.6
0.28
0.6
0.59
0.7
Total
Kjeldahl
nitrogen
(mg/L)
1.4
1.35
1.6
1.39
1.4
1
1.35
2
1.6
0.74
1.12
TP
(mg/L)
0.3
0.27
0.22
0.26
0.26
0.2
0.18
0.25
0.26
0.31
0.27
Source: Pittetal. 2004
3-106
Chapter 3. Urban and Suburban
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
Table 3-34. Median concentration of typical stormwater pollutants from urban land uses
Land use
Residential
Mixed
Residential
Commercial
Mixed
Commercial
Industrial
Mixed
Industrial
Institutional
Freeways
Mixed
Freeways
Open Space
Mixed Open
Space
Oil and
grease
(mg/L)
3.9
4.4
4.7
5
5
4.75
-
8
4
1.3
6
Fecal
coliform
(mpn/
100 mL)
8,345
11,000
4,300
4,980
2,500
3,033
-
1,700
730
7,200
2,600
As,
total
(ug/L)
3
3
2.4
2
4
3
-
2.4
3
4
3
Cd,
total
(ug/L)
0.5
0.8
0.89
0.9
2
1.6
-
1
0.5
0.38
2
Cr,
total
(ug/L)
4.6
7
6
5
14
8
-
8.3
6
5.4
6
Cu,
total
(ug/L)
12
17
17
17
22
18
-
34.7
8.5
10
10
Pb,
total
(ug/L)
12
18
18
17
25
20
5.75
25
10
10
10
Ni,
total
(ug/L)
5.4
7.9
7
5
16
9
-
9
-
-
8
Zn,
total
(ug/L)
73
99.5
150
135
210
160
305
200
90
40
88
Source: Pitt etal. 2004
Virginia-specific event mean concentrations were analyzed from the NSQD for the Virginia
Stormwater program (Center for Watershed Protection and Chesapeake Stormwater Network
2008). The analysis showed significant differences in Virginia data compared to national
averages, resulting in recommendation for use of Virginia-specific data for setting statewide or
jurisdiction-wide evaluations. Table 3-35 presents the summary of that analysis.
Chapter 3. Urban and Suburban
3-107
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
Table 3-35. Result of Evaluation of NSQD stormwater runoff quality data
comparing national and Virginia-specific EMCs
Parameter
Total Nitrogen
National
Virginia
Residential
Non-Residential
Virginia Coastal Plain
Residential
Non-Residential
Virginia Piedmont
Residential
A/on- Residential
Total Phosphorus
National
Virginia
Residential
A/on- Residential
Virginia Coastal Plain
Virginia Piedmont
Total Suspended Solids
National
Virginia
Median EMC (mg/L)
1.9
1.86
2.67
1.12
2.13
2.96
1.08
1.70
1.87
1.30
0.27
0.26
0.28
0.23
0.27
0.22
62
40
CWP & CSN. 2008. The Runoff Reduction Method, Virginia Department of
Conservation and Recreation,
April 18, 2008, Appendix G
Other sources of information on the types and concentrations of pollutants associated with land
use types are provided in Table 3-36.
3-108
Chapter 3. Urban and Suburban
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
Table 3-36. Sources of information on typical pollutants by land use type
Reference
Information provided
Infiltration vs. Surface Water Discharge: Guidance
for Stormwater Managers, Final Report. 03-SW-4,
Water Environment Research Foundation (WERF
2006)
Appendix A. Assessment of Existing Watershed
Conditions: Source of Stormwater Pollutants
Maestre, A., R. Pitt. The National Stormwater
Quality Database, Version 1.1, A Compilation and
Analysis ofNPDES Stormwater Monitoring
Information. Center for Watershed Protection, and
EPA. 2005
Selected information from monitoring conducted
for the NPDES Phase 1 Stormwater program, from
applications and subsequent monitoring, from
1992 to 2002. Approximately 3,765 events from
360 sites in 65 communities are included.
Watershed reconnaissance can be used to identify developed sites that might be hotspots of
pollutants. Certain types of land uses, particularly industrial and commercial properties, can be
significant sources of POCs that warrant source control and treatment control practices.
Managers should evaluate such land use types to identify possible pollutant sources and
determine their relative risk to water quality. Those reconnaissance efforts can help a
municipality determine the following:
• Which land use(s) and activities are most common in the watershed
• What land uses(s) are expected to change in watershed
• The pollutants that would likely dominate in Stormwater runoff, and the form of the
pollutant (as total or dissolved, for example, or as organic nitrogen or ammonia). This
information can be more difficult to obtain
• Any hotspot areas for the contamination
The identified pollutants are of concern regardless of whether they are impairing receiving
streams.
Managers should review monitoring data from the watershed for the historical period of record
to ascertain water quality characteristics and POCs. They should review water quality data for
POCs to determine information regarding the form of the pollutant, such as
• Particle-size distribution
• Pollutant partitioning or fractionation
• Pollutant speciation, which affects bioavailability, toxicity, and treatability
• Whether the pollutant is exhibited during the first flush (WERF 2005)
Chapter 3. Urban and Suburban
3-109
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
That information should be used to determine which treatment unit processes or operations
would be most appropriate if source controls are adequate.
Protecting existing uses, in addition to restoring impaired uses, is a critically important goal for
restoring any waterbody. Areas of the watershed that are of high-quality and should be protected
from degradation should also be identified. Table 3-37 provides resources for conducting
watershed assessments to identify pollutant sources and to identify areas for additional
protections.
Table 3-37. Sources of information on conducting watershed assessments
Reference
Information provided
National Management Measures
to Control Non-point Source
Pollution from Urban Areas,
EPA-841-B-05-004. (USEPA
2005a)
Watershed assessment practices include examples of programs,
methods to characterize watershed conditions and to establish
indicators
Healthy Watersheds Initiative,
www.epa.gov/healthywatersheds
(USEPA 201 Ob)
Information on Healthy Watersheds, including
- Approaches and benefits of conserving and protecting healthy
watersheds
- A systems approach to watershed assessment
- Current assessment approaches being used by regions, states,
and communities
- Conservation Approaches & Tools
- Outreach Tools
- Links to projects at the national, regional, state, and local scales
A review of results of industrial/commercial facility inspections can indicate whether these types
of properties are likely to become hotspots for pollutants. Additionally, managers can review
reports of illicit discharges, illegal connections, and illegal dumping to determine if there are
patterns in discharges that might not be predicted by land use alone, which would indicate a
need for additional outreach and education or enforcement activity. Information from past
inspections and investigations can also help to identify areas with legacy pollutants (spills,
dumping, and so on) that need to be addressed before certain types of infiltration practices
could be used. Also, managers can evaluate local planning documents to identify potential
future land uses that might become sources of pollutants.
A generalized approach for a site assessment is to
1. Identify potential sources
• By type—commercial, industrial, transportation
• By risk—of spills, leaks, illicit discharges
3-110
Chapter 3. Urban and Suburban
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
• By using existing commercial/industrial databases, land use maps, field investigations,
permit applications
2. Prioritize using
• Pollutants of Concern (POCs)
• Spill or discharge potential
• Sensitivity of watershed
• Past operation experience
3. Generate a list of potential hotspot areas prioritized according to the magnitude and
severity of risk
4. Inspect and follow up for implementing corrective measures
References for conducting site assessments are provided in Table 3-38.
Table 3-38. Resources for conducting site assessments and implementing P2 BMPs
Reference
Information provided
Urban Subwatershed and Site Reconnaissance
Users Guide. Manual 11 (Wright et al. 2005)
www.cwp.org/Resource Library/Center Docs/
USRM/USRM11 Appendix C.doc
Includes a Hotspot Site Investigation (HSI) procedure,
which quantifies a facility's impact and identifies
possible BMPs needed. An inspection form is used to
characterize the site, quantify impacts, and identify
BMPs.
Urban Subwatershed Restoration Manual No.
9: Municipal Pollution Prevention/Good
Housekeeping Practices (Novotney et al. 2008)
www.cwp.orq/Resource Library/Center Docs/
municipal/USRMQ.pdf
Guidance on how to improve ten key areas: municipal
hotspots, municipal construction, road maintenance,
street sweeping, storm drain cleanouts, stormwater
hotlines, landscaping and park maintenance,
residential stewardship, stormwater maintenance,
and employee training
Urban Subwatershed Restoration Manual No.
8: Pollution Source Control Practices (Schueler
et al. 2005)
www.cwp.orq/Resource Library/Center Docs/
USRM/ELC USRM8v2sls.pdf
Includes methods to assess Subwatershed pollution
sources, more than 100 regulatory and incentive
options, 21 specific stewardship practices for
residential neighborhoods, and 15 pollution
prevention techniques for control of stormwater
hotspots
California Stormwater Best Management
Practice Handbooks (CASQA 2004)
www.cabmphandbooks.com/industrial.asp
Guidance on preparing stormwater pollution
prevention plans, fact sheets for a variety of source
and treatment control BMPs, and information on
monitoring, reporting, and evaluation
EPA's Menu of BMPs
www.epa.qov/npdes/menuofbmps
Pollution Prevention/Good Housekeeping for
Municipal Operations BMP Fact Sheets
Chapter 3. Urban and Suburban
3-111
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
Aesthetic Issues. Finally, water quality issues that are important to the community should help to
determine POCs. For example, if a pond in a public park is being filled with sediment because of
upstream construction or algae growth is excessive, sediment and nutrients are POCs for that
pond's subwatershed.
3.1.2 Implement Pollution-Prevention and Source-Reduction Policies
Managers should review facility policy and specifications, state and local regulations, standards,
and policies, as well as the ongoing pollution-prevention programs, to determine how they can
be improved. Identify regulations, incentives or a combination of both that would be most
appropriate to address the POC through source reduction or treatment. Evaluate the pollution
prevention/source control program to ensure that it is using the most recent approaches and is
being effectively implemented.
The following are examples of types of regulations and programs to be considered for POCs:
Excess pollutants from excess runoff
• Disconnection of directly connected impervious area, such as incentives for use of
permeable pavement or for downspount disconnection
Nutrients (refer to the Turf Management Section for additional information)
• Fertilizer limitations on use (refer to the turf section of this chapter)
• Phosphate ban (e.g., laundry detergent phosphate bans in Virginia (1988), Maryland
(1985), District of Columbia (1986), and Pennsylvania (1990))
• Free yard care consultations/soil testing (e.g., services offered by cooperative extension
agencies)
Pesticides
• Inspections of commercial/industrial storage and application procedures (e.g., as part of
NPDES industrial facility inspections)
• Integrated Pest Management (IPM) incentives
• Example resources: Urban Pesticide Pollution Prevention (UPS) Project,
www.up3project.org
Trash, Oil & Grease, Pathogens
• Stormwater ordinance that addresses trash, commercial loading areas, and such
3-112 Chapter 3. Urban and Suburban
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
• Fats, oils, grease program (e.g., JEA FOG program in Jacksonville, Florida)
• Pet waste ordinance (e.g., Virginia Beach Ordinance #1237,
www.vbgov.com/file source/dept/planning/Document/LvnnhavenFecalReport2006.pdf)
Sediment
• Erosion and sediment control ordinance (EPA model erosion and sediment control
ordinance)
• Disturbed area restoration ordinance
• Tree preservation ordinance (see the Reforestation Fact Sheet)
• Buffer ordinance (EPA model aquatic buffers ordinance)
• Erosion and sedimentation control certification requirements
• Runoff volume control ordinance
Hydrocarbons, Oil/Grease
• The Spill Prevention Control and Countermeasures (SPCC) rule includes requirements
for oil spill prevention and response, including requirements for specific facilities to
prepare and implement SPCC Plans
• Requirements for covers and berms for fueling and fuel storage areas
• Green business certification to reward businesses that have taken tangible steps toward
environmental sustainability (e.g., Bay Area Green Business Program)
• Metals
• Restrictions on the amount of copper and other metals contained in brake pads sold in
Washington State in the future (State Senate Bill 6657, signed March 19, 2010)
(http://www.washington.edu/admin/pb/billtracker/)
Resources for information on pollution prevention and source reduction practices and programs
are provided in Table 3-39.
Chapter 3. Urban and Suburban 3-113
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
Table 3-39. Resources for information on stormwater pollution prevention practices
CZARA/6217
http://coastalmanaqement.noaa.gov/nonpoint/welcome.html
EPA's National Management Measures to Control Nonpoint Source Pollution from Urban Areas, 2005
www.epa.gov/owow/nps/urbanmm/index.html
EPA's Education Resources for Non-Point Source Runoff (USEPA 201 Oa)
www.epa.gov/owow/nps/eduinfo.html
EPA Menu of BMPs
www.epa.gov/npdes/stormwater/menuofbmps
California Stormwater Quality Association (CASQA) Industrial and Commercial, Handbook
www.cabmphandbooks.com/industrial.asp
2005 Stormwater Management Manual for Western Washington: Volume IV - Source Control BMPs
www.ecy.wa.gov/biblio/0510032.html
Source Water Protection Practices Bulletin: Managing Stormwater Runoff to Prevent Contamination of
Drinking Water, EPA 816-F-09-007 (USEPA 2009c)
www.epa.gov/safewater
Source Water Protection Practices Bulletin: Managing Highway Deicing to Prevent Contamination of
Drinking Water, EPA 816-F-09-008 (USEPA 2009d)
www.epa.gov/safewater
Pollution Prevention Resource Exchange, a clearinghouse for pollution prevention information
www.p2rx.org
3.1.3 Implement Source Control Practices
Source controls are the most cost-effective approach to reducing pollutant concentrations;
however, to be effective, such controls must be adopted and properly maintained. Some source
controls must be implemented as part of the design of the facility itself, such as ensuring that
vehicle maintenance operations are conducted in an area where contaminated stormwater will
not run off the site.
Table 3-40 shows some examples of source control implementation strategies targeted at specific
pollutants. Those strategies are used in many municipal good housekeeping programs and might
have applicability at federal facilities—most importantly those that are regulated as MS4s. The
Stormwater Phase II Final Rule includes, in addition to local government jurisdictions, certain
federal and state-operated small MS4s. Federal-operated small MS4s can include universities,
prisons, hospitals, military bases (e.g., state Army National Guard barracks), and office
buildings/complexes. The final rule requires the permittee to choose BMPs for each minimum
control measure. (USEPA 2005b. Stormwater Phase II Final Rule: Federal and State-Operated
MS4s: Program Implementation EPA 833-F-DD-D12 www.epa.gov/npdes/pubs/fact2-10.pdf)
3-114 Chapter 3. Urban and Suburban
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
Table 3-40. Pollution-prevention and source control practices used widely by municipal programs
may have applicability to federal facilities
Strategy/BMP
Require source controls on new and redevelopment site plans for
commercial/industrial facilities
• Require LID/infiltration practices where appropriate (not substitute for
pollutant source control, and avoid hotspots)
• Mandatory storm drain marking for all inlets in maintenance yards,
parking lots and along sidewalks
• Elimination of curb and gutter in favor of bioswales where feasible,
particularly in residential or suburban areas
• Covered dumpster areas
• Covered outdoor loading/unloading areas that drain to sanitary
sewer connections
• Covered fueling areas
• Native plant landscaping
• Irrigation management
• Develop leaf collection programs and composting/reuse programs
• Disconnected roof gutters to minimize parking lot runoff
• Curb cuts to allow parking lot runoff to run into landscaping
Implement downspout disconnection program
Provide pollution-prevention education
• Native plant landscaping
• Soil preparation, restoration, and amendments (composting)
• Water conservation (e.g., irrigation management)
• Integrated Pest Management
• Household hazardous waste disposal and used oil recycling.
• Car wash education
• Pet waste management
Require source control activities
• Cover materials/minimize exposure
• Fleet maintenance conducted inside or under cover
• Spill kits and response
• Spill training for all staff
• Parking lot maintenance
Nutrients
Pesticides
Pathogens
Sediment
Metals,
oil/grease
•
•
•
•
•
.
•
•
•
•
•
•
.
•
•
•
•
•
•
•
•
•
•
•
•
•
.
•
•
•
•
•
•
•
•
•
•
•
•
.
.
•
.
•
.
.
•
•
.
•
.
.
.
•
.
•
.
•
.
•
•
•
•
Chapter 3. Urban and Suburban
3-115
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
Table 3-40. Pollution-prevention and source control practices used widely by municipal programs
may have applicability to federal facilities (continued)
Strategy/BMP
Conduct inspections of commercial/industrial facilities to provide
compliance assistance or require implementation of controls or
both
Implement source control measures
• Cover materials/minimize exposure
• Fleet maintenance conducted inside or under cover
• Spill kits and response
• Spill training for all staff
• Street sweeping street sweeping at a monthly interval (or more
frequently) along all curbed roads with speed limits of 35 MPH or
less in urban/suburban areas; use regenerative air sweeper
technology
• Parking lot maintenance
Establish dog walking areas with signage and locations to properly
dispose of dog waste
Inspection high-priority construction projects at high frequency
M
+-
0)
^
+-
3
•2.
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
• San Mateo Countywide Water Pollution Prevention Program, which offers pollution
prevention tips geared toward citizens, business owners, and municipalities
(http://www.flowstobay.org).
• Seattle Public Utilities' Integrated Pest Management Program and ProlPM Fact Sheets
(http://www.seattle.gov/UTIL/Services/Yard/For Landscape Professionals/Integrated P
est Management/index.asp).
• North Carolina Division of Pollution Prevention & Environmental Assistance's Web site,
including the P2 infoHouse, a searchable database of pollution prevention resources
(http://www.p2pays.org).
A recent source control program in the District of Columbia is the fee on the disposable bags
from retail stores. Bags represent 47 percent of the trash in Anacostia River tributaries. The
nickel-per-bag fee is an effort to reduce litter and generate funds to clean up the Anacostia
River. The Washington Post reported that the fee was having a big effect within 3 weeks from
the program's start, reports were that the fee had cut the use of plastic bags by half or more
(Washington Post, Saturday, January 23, 2010). Reducing such nonessential waste at federal
facilities should be considered, and federal facilities should consider supporting that type of
initiative undertaken by the local governments.
3.1.4 Public Outreach
Many state and federal agencies require some form of outreach or public education and
involvement as part of their water quality laws and regulations. That type of outreach is also
applicable for federal facilities, particularly those with MS4 coverage. For example, Phase II of
EPA's NPDES stormwater regulations, which requires MS4 operators to develop and implement
stormwater management programs, state that localities are to provide opportunities for citizens
to participate in developing the program and that they distribute educational materials on
stormwater runoff. In all communities, whether regulated as MS4s or not, developing an
effective outreach campaign will help gain the critical support and compliance that will lead to
the ultimate success of a stormwater management program. Making the public aware of the
issues, educating them on what needs to be done, and motivating them to take action will help
managers meet both regulatory and water quality objectives.
Changing behavior through education and developing responsible attitudes among watershed
citizens and communities is not a simple task. EPA has provided resources to help communities
educate local citizens on how to protect local water quality through their own actions. EPA has
published Getting In Step: A Guide to Conducting Watershed Outreach Campaigns. See
http://www.epa.gov/watershed/outreach/documents/. Getting In Step approaches outreach
using concepts from social marketing. Social marketing means looking at the target audience as
Chapter 3. Urban and Suburban 3-117
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
consumers. Instead of selling products or services, social marketing sells ideas, attitudes, and
behaviors. The goal of social marketing is not to make money, but to improve society and the
environment. Social marketing campaign examples include the popular slogan "Only You Can
Prevent Forest Fires." Such campaigns persuade the public that a problem exists that only they
can solve. For example, if the goal is to encourage people to test their soil before they apply
lawn fertilizer, make it easier for them: sponsor a soil test day on which a local garden supply
store hands out free soil test kits and demonstrates their use. This approach will go a lot further
toward getting people to test their soil than merely sending out a flyer in the mail.
Getting In Step provides the overall framework for developing and implementing an outreach
campaign in concert with an overall water quality improvement effort. It presents the outreach
process as discrete steps, with each step building on the previous ones. The steps are as
follows:
• Define the driving forces, goals, and objectives
• Identify and analyze the target audience
• Create the message
• Package the message
• Distribute the message
• Evaluate the outreach campaign
The Getting in Step guide includes worksheets to help develop an outreach plan, information on
additional resources for outreach and education, publications, and other available outreach
materials.
EPA also provides the Outreach Toolbox (http://www.epa.gov/nps/toolbox/) for organizations to
use to educate the public on stormwater runoff. The toolbox contains a variety of resources to
help develop an effective and targeted outreach campaign. Features of the nonpoint source
Outreach Toolbox are
• Featured Products—Exemplary outreach examples culled from the catalog for increasing
awareness and changing behaviors across each of the six targeted topics (general
stormwater and storm drain awareness, lawn and garden care, pet care, septic system
care, motor vehicle care, and household chemicals and waste) and organized by media
type.
• Searchable Catalog—Contains more than 700 viewable or audible TV, radio, and print
ads and other outreach products to increase awareness and/or change behaviors across
six common topics (see Featured Products). Search by media type or topic. Permissions
3-118 Chapter 3. Urban and Suburban
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
for using the cataloged products are disclosed (and in most cases, granted) by the
product owners, and contact information, campaign Web sites, and other pertinent
details are provided.
• Other Nonpoint Source Outreach Collections—Links to collections of nonpoint source
outreach and educational products compiled by states and other organizations.
3.1.5 Disconnecting Directly Connected Impervious Areas, Such as
Downspout Disconnection
In many urban areas, roof downspouts are connected to the storm sewer system or, in some
cities, to combined sewer systems. Disconnecting the downspouts allows the roof runoff to drain
to the lawn or garden and infiltrate. Disconnection might not be applicable in all situations,
depending on safety and property protection needs of each site. One example of a municipal
downspout disconnection program is in Baltimore, Maryland (at http://bavwatersheds.org/wp-
content/uploads/2010/03/DownsputDisconnectionBrochure2010.pdf). The program, which
targets sites in the Herring Run and Jones Falls watersheds, provides free surveys and
disconnections for homeowners. The program also helps residents install rain barrels and rain
gardens.
3.1.6 Inspections of Commercial/Industrial Facilities
A pollution-prevention program should include a component that tracks commercial/industrial
activity and includes conducting routine and random inspections of commercial/industrial
facilities. The program can be used to provide compliance assistance or to ensure
implementation of controls, such as those required under a municipal ordinance. The activity is
an integral component of the NPDES MS4 stormwater permit requirements, and technical
guidance on approaches for inspection programs—for MS4 communities or for other entities—is
provided in EPA's MS4 Program Evaluation Guidance, Chapter 4.6 Industrial/Commercial
Facilities, January 2007, http://www.epa.qov/npdes/pubs/ms4quide withappendixa.pdf. This
guidance can provide useful information in implementing a program or survey of
industrial/commercial operations at federal facilities.
In addition, the Chesapeake Stormwater Network has developed a Stormwater Pollution
Benchmarking Tool for existing industrial, federal and municipal facilities in the Chesapeake Bay
Watershed (http://csnetwork.sguarespace.com/whatsnew/csn-releases-technical-bulletin-
7.html). The tool guides facilities through a comprehensive assessment of its site to identify
stormwater problems and retrofit opportunities, using 22 stormwater benchmarks. The tool also
helps facilities develop an action plan to enhance stormwater pollution-prevention efforts at their
individual facility
Chapter 3. Urban and Suburban 3-119
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
Examples of stormwater inspection programs for commercial/industrial facilities that might be
useful for federal facilities include the following:
• Contra Costa, California Commercial & Industrial Business Inspection Plan, 2005,
http://www.ci.brentwood.ca.us/pdf/npdes/commerial industrial inspection plan 05.pdf
• Sacramento County Stormwater Quality Program,
http://www.sactostormwater.org/industrial/compliance.asp
Key technical components of an inspection program that might be applicable to federal facilities
include the following (USEPA 2007):
• Facility Inventory. Characterize the facilities and prioritize them on the basis of their
potential effect on stormwater quality, and the inspection program should be based on
that prioritization approach.
• Tracking. A database facilitates program management. The database inventory should
include facility type, past inspection or enforcement results, proximity to receiving
waters, potential pollutant sources on-site, and other pertinent information to assist in
inspection prioritization and management.
• Standards, BMPs, and Outreach. Many facilities have stormwater-specific stormwater
management standards for industrial and commercial facilities to protect water quality
and minimize stormwater pollution. Developing brochures, fact sheets, and posters to
hand out to operators during inspections is useful for educating them about appropriate
BMPs and inform them of what to expect from the inspection program.
• Staff Training. Routine training to ensure that inspectors are knowledgeable is essential
to minimizing stormwater pollution from industrial/commercial facilities. It is important to
cross-train any other staff used for stormwater inspections as well.
• Inspections. Most effective industrial/commercial inspection programs maintain a
complete facility inventory and group them according to site-specific priorities. Inspection
frequency is determined according to priority. An inspection standard operating
procedure should be formalized and documented. It should include a checklist to be
used during the inspection and possibly a report format. Inspectors should be aware of
federal, state, and local stormwater regulations that might apply to industrial/ commercial
facilities. Inspectors should be familiar with various types of BMPs commonly used at the
types of facilities being inspected and should be able to educate facility operators about
such BMPs. Inspections should be used to identify noncompliance issues and as an
opportunity to educate facility operators about proper stormwater BMPs.
• Program Support and Resources. Inspection programs should be included in the
operating budget.
3-120 Chapter 3. Urban and Suburban
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
3.2 Runoff Treatment
3.2.1 Identify Pollutants of Concern
Approaches for identifying POCs are discussed under 3.1.1 Source Control/Pollution
Prevention. For the Chesapeake Bay, POCs include N, P, and sediment. Source control and
pollution prevention are the most effective means for reducing pollutant concentration, used with
runoff minimization. Treatment should be used as needed, in addition to the measures of
pollutant reduction and runoff minimization to mitigate the identified POCs.
3.2.2 Select Treatment Practices Appropriate to the POC
Treatment Practices and Design Guides. Treatment controls for stormwater, and estimates of
their effectiveness, have been summarized in the literature. Example references are provided in
Table 3-40. In general, the effectiveness for removing virtually all pollutants, with the exception
of gross solids and heavy particulates, is highly variable because of the differences in practice
design, nature of pollutants, changes in watershed conditions, and variability in storm
characteristics (Stormwater Best Management Practices (BMP) Performance Analysis,
December 2008, prepared for EPA by Tetra Tech).
Table 3-41 also includes references to sources of information on manufactured devices that
might be useful as pretreatment before LID practices.
Table 3-41. References on general stormwater treatment BMP type, effectiveness, and design
approaches
Reference
Information provided
Stormwater Treatment BMPs
EPA's Stormwater Best Management Practices
Design Guide, Volumes 1-3 (121, 121A, 121B),
September 2004. U.S. Environmental Protection
Agency, Office of Research and Development,
EPA/600/R-04/121,
www.epa.aov/nrmrl/pubs/600r04121/600r04121.htm
Infiltration vs. Surface Water Discharge: Guidance for
Stormwater Managers, Final Report. 03-SW-4, Water
Environment Research Foundation (WERF 2006)
Maryland Stormwater Design Manual
www.mde.state.md.us/Proqrams/WaterProqrams/
SedimentandStormwater/stormwater desiqn/index.asp
Three volume series provides guidance when
selecting BMPs (either through retrofitting of
existing BMPs or applying newly constructed
BMPs to new development) to prevent or
mitigate the adverse effects of urbanization
Describes the performance of infiltration basins,
bioretention, grass swales, porous pavement,
as well as design and maintenance guidelines,
and methods for modeling performance.
Appendix D. Literature Review Supporting
Design of Infiltration BMPs.
Sizing and performance criteria for urban BMPs
Chapter 3. Urban and Suburban
3-121
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
Table 3-41. References on general stormwater treatment BMP type, effectiveness, and design
approaches (continued)
Reference
Stormwater Best Management Practices (BMP)
Performance Analysis, December 2008, prepared for
EPA by Tetra Tech
Center for Watershed Protection Technical
Memorandum: The Runoff Reduction Method
www.cwp.orq/Resource Library/Center Docs/SW/RR
TechMemo.pdf
Water Environment Research Foundation. 2005b.
Performance and Whole-Life Costs ofBMPs and
SUDS
www.werf.orq/AM/Template.cfm?Section=Search&Te
mplate=/CustomSource/Research/ResearchProfile.cfm
&ReDOrtld=01-CTS-21-
TA&CFID=271 5758&CFTOKEN=758051 27
International Stormwater Database
www.bmpdatabase.ora
Technology Acceptance & Reciprocity Partnership
(TARP)
Washington State Department of Ecology, Evaluation
of Emerging Stormwater Treatment Technologies
www.ecy.wa.qov/proqrams/wq/stormwater/newtech/
index.html
Center for Watershed Protection's National Pollutant
Removal Performance Database, Version 3
www.cwp.ora/Resource Library/Center Docs/
SW/bmpwriteup 092007 v3.pdf
Determining Urban Stormwater BMP Effectiveness
http://books.qooqle.com/books?id=p5qMMwofaDwC&
loq=PA1 75&ots=Z 1 Tvw560G&lr=&oq=PA1 75#v=on
epaqe&q=&f=false (Strecker et al. 2000)
Information provided
A procedure and results for estimating long-
term performance for several types of LID
BMPs designed and maintained in accordance
with Massachusetts stormwater standards, but
the procedure could be applied in other areas
A framework for BMP designers to verify
compliance with proposed stormwater
regulations in Virginia
Research on stormwater BMP effectiveness
and cost
Compendium of results from studies of BMP
effectiveness
Testing protocols and performance reports for
manufactured pretreatment devices
Program for evaluating stormwater
technologies proposed by vendors, and a
clearinghouse for information and decisions on
their use
Compendium of results from 166 studies of
BMP effectiveness
Discussion of protocols for measuring and
reporting BMP effectiveness.
Design Approaches
Chesapeake Stormwater Network's Baywide Design
Specifications
www.chesapeakestormwater.net/baywide-desiqn-
specifications2
U.S. Department of Defense. 2004. Unified Facilities
Criteria (UFC) Low Impact Development
httD://www.wbdq.orq/ccb/NAVFAC/INTCRIT/ufc 3 21
0 10n.Ddf
Detailed design specifications for rooftop
disconnection, filter strips, grass channels, soil
compost amendments, green roofs, rain tanks,
permeable pavers, infiltration, bioretention, dry
swales, urban bioretention, filtering practices,
constructed wetlands, wet ponds, and extended
detention ponds
Design criteria and examples for LID practices
3-122
Chapter 3. Urban and Suburban
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
Table 3-41. References on general stormwater treatment BMP type, effectiveness, and design
approaches (continued)
Reference
City of Portland 2008 Stormwater Management
Manual
www.portlandonline.com/BES/index.cfm?c=47952
Strecker, E., M.M. Quigley, and B.R. Urbonas. 2000.
Determining urban stormwater BMP effectiveness. In
Proceedings of the National Conference on Tools for
Urban Water Resources, February 7-10, 2000,
Chicago, IL.
Information provided
Typical design details for a number of LID
BMPs for urban settings
Overview of BMP effectiveness
Table 3-42 lists some of the design manuals that have a specific focus on treatment of nutrients;
it is not intended to be a comprehensive list, and updates are routinely made as technology
advances.
Table 3-42. Stormwater treatment design manuals or specifications with focus on nutrient removal
for urban stormwater
Reference
Developing Nitrogen, Phosphorus and Sediment
Reduction Efficiencies for Tributary Strategy Practices,
BMP Assessment Final Report
www.chesapeakebay.net/marylandBMP.aspx (Simpson
and Weammert 2009)
New York State Stormwater Management Design
Manual, Chapter 10: Enhanced Phosphorus Removal
Standards
www.dec.ny.aov/chemical/29072.html
Chesapeake Stormwater Network Baywide Design
Standards (CSN 2010)
www.chesapeakestormwater.net/all-thinqs-
stormwater/cateqorv/baywide-desiqn-specifi cations
New Jersey Stormwater Best Management Practices
Manual
www. state. ni.us/dep/stormwater/bmp manual2.htm
Northern Virginia BMP Handbook
www.novareqion.orq/DocumentView.aspx?DID=1679
Virginia Stormwater BMP Clearinghouse
www.vwrrc.vt.edu/swc/NonProprietaryBMPs.html
Information provided
Effectiveness estimates, focusing on nutrients
and sediment, for a number of urban,
agricultural, and forestry BMPs
Phosphorus removal section recently added
Specifications for 15 stormwater BMPs
Chapter 4 includes information on meeting
nutrient removal performance standards, and
Chapter 9 includes design standards
BMP manual with design calculations for
phosphorus removal
BMP design specifications
The potential for trees and other vegetation to remove pollutants from stormwater as a
treatment practice has been evaluated in phytoremediation research but has not yet been
Chapter 3. Urban and Suburban
3-123
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
widely studied for applicability in sequestering pollutants removed from stormwater or for
extending the life of bioretention media. Plants provide nutrient uptake, toxin uptake such as
heavy metals, and pollutant breakdown. This is an area for future research. Resources for
information on phytoremediation is included in Table 3-43.
Table 3-43. Resources for information on phytoremediation
Reference
Phytotechnology Technical and Regulatory Guidance,
The Interstate Technology & Regulatory Council 2009
(http://www.itrcweb.orq/Documents/PHYTO-3.pdf)
EPA's Brownfields Technology Primer:
Selecting and Using Phytoremediation for Site
Cleanup (http://www.clu-
in.orq/download/remed/phvtoremprimer.pdf)
Phytotechnology Project Profiles
(http://www.clu-in.ora/products/phvto/)
Type of information
Provides guidance on using vegetation for soil
remediation, and estimates of transpiration
rates
Phytoremediation process, advantages and
considerations, and additional resources
Case studies demonstrating phytotechnology
applications
Assessing Treatment Technologies. Understanding unit operations and processes is
necessary for success of the treatment system design, as well as system O&M. This modern
approach for stormwater treatment is based more on traditional industrial drinking water and
wastewater treatment concepts, rather than on traditional stormwater approaches that generally
addressed only the more basic goal of removing total suspended solids. This approach is
presented in Critical Assessment of Stormwater Treatment and Control Selection Issues (WERF
2005a), and is applicable as treatment concerns become more focused on removal of P and N.
The approach advises users to first select unit operations or processes applicable for POCs on
the basis of the pollutant form (i.e., dissolved, colloidal, particulate), chemical speciation (e.g.,
ionic metal species, P species), and granulometric characteristics (e.g., particle size, specific
gravity, surface area), and then individually select the components of a treatment system
according to the unit operations or processes that are effective for treating the POCs (see
Table 3-44). For example, this approach is presented in the New York State Stormwater
Management Design Manual, Chapter 10: Enhanced Phosphorus Removal Standards.
A benefit to the LID-approach for stormwater management, both infiltration/evapotranspiration
and harvest and use such as in irrigation or in toilets, is that reduction of the runoff volume often
translates to a runoff in pollutant loading, as well as the benefit of reducing the excess volumes
of scouring, flash-flooding runoff.
3-124
Chapter 3. Urban and Suburban
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
Table 3-44. Unit operation or processes and typical treatment system components for
fundamental process categories
Fundamental
process category
(FPC)
Hydrologic Operations
Physical Treatment
Operations
Unit operation or process (UOP)
Target Pollutants
Flow and Volume
Volume Reduction
All Pollutant loads
Particle Size Alteration
Coarse sediment
Physical Sorption
Nutrients, metals, petroleum
compounds
Size Separation and Exclusion
(screening and filtration)
Coarse sediment, trash, debris
Density, Gravity, Inertial
Separation (grit separation,
sedimentation, flotation and
skimming, and clarification)
Sediment, trash, debris, oil and
grease
Aeration and Volatilization
Oxygen demand, PAHs, VOCs
Physical Agent Disinfection
Pathogens
Typical treatment system components
(TSSC)
Extended retention/detention ponds
Wetlands
Tanks/vaults
Equalization basins
Infiltration/exfiltration trenches and basins
Permeable or porous pavement
Bioretention cells
Dry swales
Dry well
Extended detention basins
Comminutors (not common for stormwater)
Mixers (not common for stormwater)
Engineered media, granular activated
carbon, and sand/gravel (at a lower
capacity)
Screens/bars/trash racks
Biofilters
Permeable or porous pavement
Infiltration/exfiltration trenches and basins
Manufactured bioretention systems
Engineered media/granular/sand/compost
filters
Hydrodynamic separators
Catch basin inserts (i.e., surficial filters)
Extended detention basins
Retention/detention ponds
Wetlands
Settling basins, tanks/vaults
Swales with check dams
Oil-water separators
Hydrodynamic separators
Sprinklers
Aerators
Mixers (not common for stormwater)
Shallow detention ponds
Ultraviolet systems
Chapter 3. Urban and Suburban
3-125
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
Table 3-44. Unit operation or processes and typical treatment system components for
fundamental process categories (continued)
Fundamental
process category
(FPC)
Biological Processes
Chemical Processes
Unit operation or process (UOP)
Target Pollutants
Microbially Mediated
Transformation (can include
oxidation, reduction, or facultative
processes)
Metals, nutrients, organic
pollutants
Uptake and Storage
Metals, nutrient, organic
pollutants
Chemical Sorption Processes
Metals, nutrients, organic
pollutants
Coagulation/Flocculation
Fine sediment, nutrients
Ion Exchange
Metals, nutrients
Chemical Disinfection
Pathogens
Typical treatment system components
(TSSC)
Wetlands
Bioretention systems
Biofilters (and engineered bio-media filters)
Retention ponds
Media/sand/compost filters
Wetlands/wetland channels
Bioretention systems
Biofilters
Retention ponds
Subsurface wetlands
Engineered media/sand/compost filters
Infiltration/exfiltration trenches and basins
Detention/retention ponds
Coagulant/flocculant injection systems
Engineered media, zeolites, peats, surface
complexation media
Custom devices for mixing chlorine or
aerating with ozone
Advanced treatment systems
Source: WERF 2005
Estimating Effectiveness of Stormwater Treatment Practices. As noted previously,
estimates of the effectiveness of stormwater treatment practices vary for many reasons. The
effectiveness of any stormwater BMP—for example, in annual pounds of pollutant removed or in
percent of pollutant removed—will be a function of the rainfall pattern, the specific design of the
BMP, the watershed and pollutant characteristics, and—for practices that include infiltration or
filtration—the nature of the media. Media with high P or N content can export nutrients, while
providing effective removals of trace metals. For more information on factors influencing the
treatment effectiveness of bioretention and other LID practices, see the Fact Sheets.
A list of stormwater treatment BMPs, and their estimated effluent mean concentrations are
provided in Table 3-45. The values are used in a WERF stormwater treatment model (the model
name is SELECT) and provide an indication of the effluent quality that may be observed from
the practices.
3-126
Chapter 3. Urban and Suburban
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
Table 3-45. Default effluent event mean concentration for BMPs used in WERF SELECT model
BMP
Extended Detention3
Wetland Basins3
Bioretention3
Swalesb
Media Filters3
Permeable Pavement3
TSS
(mg/L)
MED
31
18
24
13
16
18
STD
2
1
2
1
1
1
TP
(mg/L)
MED
0.19
0.14
0.34
0.22
0.14
0.14
STD
0.04
0.02
0.06
0.05
0.03
0.03
TN
(mg/L)
MED
2.72
1.15
0.78
2.72
0.76
1.15
STD
0.5
0.2
0.1
0.4
0.1
0.15
Source: Pomeroy and Rowney 2009
a. Geosyntec Consultants and Wright Water Engineers 2008.
b. Barrett etal. 1998
Estimates of potential pollutant-removal effectiveness were summarized on the basis of a
literature review of data on the Chesapeake Bay watershed (Recommendations for
Endorsement by the Chesapeake Bay Program Nutrient Subcommittee and its Workgroups For
use in Tributary Strategy Runs of Phase 5 of the Chesapeake Bay Program Watershed Model;
Collins et al. 2009, www.chesapeakebay.net/marylandbmp.aspx). The pollutant-removal
estimates provided indicate that the majority of annual reduction in pollutant loading is derived
from volume reduction, although some treatment can be achieved with appropriate media (low
N and P content) and the conditions to enable denitrification to occur. Estimates of performance
for LID practices, and other urban stormwater treatment practices, are provided for the
following:
• Dry detention ponds and hydrodynamic structures BMPs
• Dry extended detention basins BMP
• Infiltration and filtration practices (includes bioretention, permeable pavement, infiltration
trenches and basins, filters, and vegetated open channels)
• Urban wet ponds and wetlands
Infiltration and filtration practices have the best potential for addressing nutrient treatment of the
because of the processes that can occur in the soils (if the soils are not nutrient-rich). LID
technologies that do not provide treatment include green roofs, which provide volume reduction,
and harvesting/blue roofs, which can provide volume reduction if flows are used for irrigation,
other use, or can be evaporated. Note that infiltration through soils via applications such as
bioretention are different from dry wells because a level of treatment is provided in the soil (see
the 2008 EPA memorandum that clarifies that typical stormwater infiltration compared to dry
Chapter 3. Urban and Suburban
3-127
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
wells, www.epa.gov/npdes/pubs/memo gi classvwells.pdf) (USEPA 2008a). The performance
estimates for infiltration and filtration practices are provided in the Bioretention Fact Sheet in
Appendix 1.
Actual pollutant-removal performance can vary significantly depending on many factors,
including regional rainfall pattern, media specification, design features, and watershed
characteristics that affect the pollutant concentration and speciation. To obtain more accurate
estimates, approaches that combine pilot testing with continuous hydrologic modeling have
been performed, for example in EPA Region 1. That type of approach could be successful in
developing more accurate performance estimates for specific climate regions and practice
designs (Stormwater Best Management Practices (BMP) Performance Analysis, prepared by
Tetra Tech, Inc., for EPA Region 1 2008,
www.epa.gov/region1/npdes/stormwater/assets/pdfs/BMP-Performance-Analysis-Report.pdf).
Long-Term Maintenance Considerations. Maintenance requirements should be evaluated as
part of practice selection to help enable a more accurate comparison of the life-cycle costs of
the practice. Maintenance considerations can include
• Necessary maintenance activities for the life of the control compared to alternatives
• How placement of the practice can affect maintenance (visibility, and such)
• Level of effort necessary to ensure adequate maintenance
• Frequency of maintenance necessary
• Responsible party to conduct maintenance or ensure continuing use of areas in drainage
easements, and mechanisms for enforcement
Resources for information on maintenance considerations are provided in Table 3-46. Additional
maintenance information is provided in the fact sheets in Appendix 1. Information on LID O&M
costs is provided in Section 2 of this chapter.
3-128 Chapter 3. Urban and Suburban
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
Table 3-46. Resources for information on maintenance considerations
Stormwater Manager's Resource Center Manual Builder
www . sto rmwate rcenter.net
Virginia's Maintaining Your BMP: A Guidebook for
Private Owners and Operators in Northern Virginia
(VADCR 2009b)
www.dcr.virainia.aov/chesaoeake bav local assistance
/documents/bmpmaintfinal.pdf
Lake County, Illinois' A Citizen's Guide to Maintaining
Stormwater Best Management Practices for
Homeowners Associations and Property Owners
www.northbarrinaton.ora/files/newsletters/Guide Final
110404.odf
Pierce County, Washington's Stormwater Maintenance
Manual for Private Facilities
www.co.pierce.wa.us/xml/services/home/environ/water/
wa/maintman/MaintManFinal2-22-05.pdf
Information on maintenance tracking,
frequencies, unit costs, easements,
performance bonds, and checklists for
maintenance inspections for common BMPs.
Maintenance guidance for homeowners,
homeowners associations, and other,
nontechnical audiences.
Step-by-step guide for planning for and
conducting maintenance on common
Stormwater BMPs.
Includes BMP-specific maintenance
information and checklists as well as
information on developing a maintenance
program.
Physical Site Limitations. Physical site limitations can affect the appropriateness of a practice.
These can include the following:
• Lack of adequate pervious area to infiltrate Stormwater
• Presence of functionally impervious soils
• Steep slopes or a high groundwater table
• Presence of contaminated soils
• Potential for highly contaminated Stormwater (from hotspots) infiltrating and
contaminating groundwater source
• Proximity to building foundations, roadways, bridges, abutments, and retaining walls
• Lack of necessary vertical relief to transport Stormwater flows
• Conflicts with underground utilities
Example resources for information on some of the site limitation issues are provided in
Table 3-47.
Chapter 3. Urban and Suburban
3-129
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
Table 3-47. Example resources for information on some of the many site limitation issues to
consider
Resource
CSN Technical Bulletin No. 1 Stormwater Design Guidelines for
Karst Terrain in the Chesapeake Bay Watershed Version 2.0,
Chesapeake Stormwater Network, Developed by Karst Working
Group, Released June 2009
Groundwater Contamination Potential from Infiltration of Urban
Stormwater Runoff. Shirley E. Clark, Robert Pitt, and Richard
Field; To be published 2009 as Chapter 6 in The Effects of
Urbanization on Groundwater: An Engineering Case Based
Approach for Sustainable Development. Committee on
Groundwater Hydrology, ASCE/EWRI.
Center for Watershed Protection (CWP 2001) Stormwater
Practices for Cold Climates
www.stormwatercenter.net/Cold%20Climates/cold-climates.htm
Urban Small Sites Best Management Practice Manual, Chapter 2:
Selecting BMPs (Metropolitan Council 2009)
www.metrocouncil.ora/environment/Water/BMP/manual.htm
Limitation addressed
Infiltration practices in Karst areas
Risk of groundwater contamination
from infiltration practices
Cold-climate considerations,
including freezing temperatures and
high runoff during snowmelt
Includes a matrix of physical
feasibility factors to aid in selecting
BMPs
Aesthetics and Safety. When selecting and designing BMPs, it is important to consider the
surrounding land use type, the immediate context, and the proximity of the site to civic spaces to
ensure that the site's aesthetics are preserved. Also, access to BMP areas should be limited to
protect public safety. Finally, water should not be allowed to stand for longer than 72 hours to
prevent mosquito breeding. More information about aesthetic and safety considerations is at the
WERF Using Rainwater to Grow Livable Communities (WERF 2008b) site
(www.werf.org/livablecommunities), particularly on the Green Infrastructure Design
Considerations page (www.werf.org/livablecommunities/pdf/design.pdf).
3-130
Chapter 3. Urban and Suburban
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
4 Urban Runoff Management for the
Redevelopment Sector
The implementation measures listed in Section 2 for reducing runoff volume are expanded in
this section because of the importance of addressing redevelopment in the restoration of the
Chesapeake Bay or other urban waterbodies.
The implementation measures specifically applicable to redevelopment (repeated from
Section 2) are below.
Implementation Measure U-9 (in part):
Develop and implement redevelopment programs that identify opportunities for a
range of types and sizes of redevelopment projects to mitigate water resource
impacts that
• Establish appropriate redevelopment stormwater performance standards
consistent with the goal of restoring predevelopment hydrology with
regard to the temperature, rate, volume and duration of flow, or more
restrictive if needed for site-specific water quality protection, as
determined by the appropriate regulatory authority for the region or site.
• Include development of an inventory of appropriate mitigation practices
(e.g., permeable pavement, infiltration practices, green roofs) that will be
encouraged or required for implementation at redevelopment sites that
are smaller than the applicability threshold
• Include site assessment to determine appropriate GI/LID practices
• Review facility planning documents and specifications (as well as any
applicable codes and ordinances) and modify as appropriate to allow
and encourage GI/LID practices
• Implement GI/LID demonstration projects
• Incentivize early adopters of GI/LID practices
• Maximize urban forest canopy to reduce runoff
• Conduct soil analyses and amend compacted urban soils to promote
infiltration
Chapter 3. Urban and Suburban 3-131
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
About 50 percent of the residential, commercial, and industrial buildings present in the year
2030 will be constructed between 2000 and 2030 (Brookings Institute 2004), creating
opportunities for water quality improvements that our cities must seize if we are to achieve the
goals of restoring the Chesapeake Bay or other urban waters. As redevelopment projects occur
over several decades, pollutant discharges from developed areas can be gradually reduced as
practices are installed to incrementally improve the quality of runoff from existing, untreated
developed land.
Sound redevelopment practices incorporate principles of smart growth and sustainable
development (USEPA 2005c, 2006). LID practices installed at redevelopment projects in
catchments that are served by combined sewer systems can help reduce the frequency and
magnitude of CSOs to rivers and estuaries (Limnotech 2007).
Well-planned redevelopment is necessary for many reasons other than just water quality,
prompting a growing number of redevelopment project designers and communities to develop
holistic approaches for achieving water quality improvements in the redevelopment process in
combination with other social, economic, and environmental factors. Water quality programs are
an important component of a healthy, vibrant, livable, and environmentally sound community
and are a key factor to consider in a redevelopment project.
Encouraging redevelopment, rather than Greenfield development:
• Promotes land use efficiency
• Improves the quality of life in urban areas
• Optimizes use of existing public infrastructure
• Provides a tax base to enable maintenance of existing public infrastructure
LID and green infrastructure stormwater requirements create an excellent opportunity to
facilitate mitigation of the effects of past development at the site or watershed scale, and to
address other societal objectives.
Challenges and Opportunities in the Redevelopment Sector. Redevelopment projects
require innovative, cost-effective, LID solutions to overcome challenges such as the following:
Site Constraints. Most infill and redevelopment projects are small in area, highly
impervious, and have existing utilities and infrastructure, all of which constrain
the use of some traditional stormwater practices, particularly those that rely on
infiltration through vegetative practices.
3-132 Chapter 3. Urban and Suburban
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
High Trash Loads. Runoff from highly urban watersheds is often severely
polluted and contains a high load of trash, litter, debris and gross solids (City of
Baltimore 2006), which can interfere with the performance of stormwater
practices and creates the need for more frequent practice maintenance.
Compacted and Polluted Soils. Soils have been graded, eroded, and reworked
by past development, often resulting in compaction such that runoff cannot be
effectively infiltrated. In severe cases, legacy problems from past industrial and
municipal activity have created brownfields that must be capped to prevent
infiltration from leaching pollutants or contaminating soils (USEPA 2008b). For
those sites with compacted or polluted soils, using infiltration practices might be
limited. Example case studies are provided at EPA's Brownfields Program
(http://www.epa.gov/brownfields/tools/swcs0408.pdf) (USEPA 2008c).
Natural Stream Network is Altered or Buried. Urbanization has severely altered,
reduced or eliminated the natural stream network (NRC 2008). The urban stream
system that remains is often highly degraded and altered in size and shape, and
most development projects discharge to existing storm drain pipes or
conveyance channels rather than streams.
Feasibility and Cost of Compliance. The cost of stormwater practices at
redevelopment projects in highly urban settings is often more expensive than in
new development projects in greenfield settings, where more surface land is
available for the practices (Schueler 2007). The potential exists for other types of
cost savings or amenity benefits, and they should be considered in addition to
capital cost comparisons (Portland BES 2007).
Redevelopment Should Focus on Both Source Control (Pollution Prevention) and
LID. Redevelopment sites in the Chesapeake Bay watershed and elsewhere in
the nation often discharge to receiving waters that are listed as water quality
impaired and require pollutant reductions through TMDLs for a range of
pollutants, including bacteria, trash, nutrients, metals and hydrocarbons. All these
varied sources should be addressed in redevelopment.
Smart Growth Considerations. Integrating LID practices into high-density land
development is an essential element of creating desirable smart growth
communities with green infrastructure, and sustainable cities, but it can be a
challenge, especially for designers and developers unfamiliar with the practices.
Therefore, it is important that managers select stormwater practices that will be
consistent with those important redevelopment principles.
Chapter 3. Urban and Suburban 3-133
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
Because of those constraints, many urban communities in the Chesapeake Bay watershed (and
elsewhere in the nation) have historically waived, relaxed, or otherwise reduced stormwater
requirements for redevelopment projects. That has contributed to the continuing deterioration of
urban waters. However, in recent years, stormwater managers have taken a more creative
approach to treating stormwater from the redevelopment sector (see Figure 3-22 for example)
that reflects the following opportunities:
New Redevelopment Practices. In the past decade, considerable research has
been conducted, demonstrations made, and experience gained—all of which
demonstrate that a variety of LID practices can be used that are specifically
adapted for highly urban areas. Those include practices such as expanded tree
boxes with supporting structures to prevent soil compression under pavements,
green roofs, permeable pavements, and flexible rubber sidewalk sections
allowing for less destructive tree root growth). The new practices emphasize the
sustainable use of stormwater as part of green buildings and green infrastructure.
In addition, the new practices promote larger sustainability objectives such as
increased energy efficiency and water conservation, greater building longevity,
community greening, safer and more walkable communities, cleaner and cooler
air in the summer, habitat for birds, and more creative architectural solutions.
Green Building and Sustainability Movement. Designers are seeking green
certifications for their buildings, and points are awarded for using innovative
stormwater practices. Other certification systems reward effective stormwater
solutions for the entire site and not just the building itself. Together, such
certification systems provide powerful incentives to create innovative stormwater
solutions for redevelopment projects.
Municipal Leadership on Green Infrastructure. Federal facilities can look to cities
that have found that a green approach to designing their streets, parking lots,
and buildings can provide multiple benefits in the urban setting, and have
retrofitted their infrastructure designs and building codes to allow for green
streets and streetscapes, urban forestry, and landscaping areas to treat
stormwater (City of Emeryville 2005; City of Philadelphia 2008; City of Portland
2008b; San Mateo County 2009).
3-134 Chapter 3. Urban and Suburban
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
With CSO abatement costs expected into the billions, in 1996 the Philadelphia Water Department (PWD),
determined that after implementing conventional solutions, local waterways would still have eroded banks
poor water quality and habitat. PWD decided to simultaneously address CSOs, the stormwater permit,
Clean Drinking Water Act requirements, and repeated flooding, while preserving watershed health. Their
strategy targets the sources of urban runoff and water quality problems rather than just symptoms.
Philadelphia is focusing on
• A performance-based stormwater ordinance to create incentives for BMP use
• Pilot BMPs for research and education
• A stormwater rate reallocation study to migrate to an impervious-area-based formula
The ordinance encourages a return to predevelopment conditions requiring developers to manage the first
inch of stormwater on-site. PWD partnered with other city departments to set up a new development review
process. At one time PWD was the last to see development plans, now they are among the first, so they
can request changes in designs to accommodate water quality goals before plans are finalized.
The building industry would have more requirements with the new regulations, but the city knew that these
were not so different from what they face with greenfield development. The development community could
be creative and use combinations of practices to meet the water quality, CSO abatement, and flood control
requirements. So many requirements exist for development of green space, that infill development in
Philadelphia is easier than in suburban areas.
Some chaos ensued in the first three months of the new ordinance, with pushbackfrom developers and
city agencies. Waivers were requested, none were granted. Only a small fraction resorted to in-kind trades
implementing BMPs offsite but in the same sewershed. One year and approximately 500 development
plans later, the city has seen a significant change in the regulated community. Developers learned which
firms adapted to the requirements and can sail through review. There has been a substantial decrease in
resubmissions.
The green development buzz spread. Developers realized that these BMPs offer benefits beyond
stormwater control, and they are trying innovative approaches on their own as part of the trend to build
more sustainable (e.g., LEED-certified) buildings. Recently, a public housing authority chose to install
porous pavement because it was comparably priced and would allow for smaller drainage pipes. Infill
developers garner support for a project by highlighting the potential to reduce neighborhood flooding, as
the new requirements turn back the clock and improve on predevelopment conditions.
Demonstrating the Benefits of Green Infrastructure BMPs. How do these practices benefit rate payers?
PWD showed quantitatively how the approaches help maintain streams and support more conventional
infrastructure. They demonstrated cost benefits: each dollar spent on green practices resulted in a tangible
improvement. Specifically, staff showed that the stormwater rate reallocation was estimated to alleviate the
need for tanks that control 40 million gallons of stormwater, offering a direct financial benefit to the city. All
of these efforts gradually changed the image of an institution that historically has been more comfortable
with more engineered solutions. Now city officials come to PWD with green ideas of their own.
Future Expectations for the Successful Redevelopment Program. The city expects that charges to
residential customers would remain the same or decrease, whereas charges to commercial customers
would increase somewhat, as would be expected based on the relative amounts of impervious surface.
The city provides other financial incentives, as well, such as a new tax credit for green roofs. Over the long
term, the city expects that the stormwater fee will encourage more BMP implementation. They hope that
businesses and institutions will consider the balance between initial capital costs for installing a BMP with
the reduction over the long term in the rate charged for the stormwater utility.
PWD's staff enjoys the praise they receive from the community on individual projects and from other cities
who want to learn from their successes. They are pleased that the development community has embraced
the new stormwater regulations and have started to take the initiative in implementing green solutions.
Source: Adapted from the Water Environment Federation Livable Communities
http://www.werf.org/livablecommunities
Figure 3-22. Philadelphia: A successful redevelopment approach to restoring water quality, using
a municipal example, shows how standards to manage stormwater on-site are accepted into
facility planning approaches.
Chapter 3. Urban and Suburban 3-135
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
4.1 Establish Stormwater Performance Standards for the
Redevelopment Sector Consistent with the Goal of
Restoring Predevelopment Hydrology
For all redevelopment sites, establish the means of determining compliance with the
performance standard for runoff volume reduction or pollutant reduction. The federal
government is leading by example by requiring runoff volume reduction that would either be
equivalent to that of predevelopment hydrology, or as a default depth, from the 95th percentile
rainfall event. That requirement applies for redevelopment projects at federal facilities and lands
nationwide, and is described in U.S. DoD (2009) and USEPA (2009e). It is derived from section
438 of the 2008 Energy Independence and Security Act. In the Chesapeake Bay watershed,
that LID requirement would apply to about 1.5 to 1.9 inches of rainfall, depending on where the
project is in the watershed.
4.2 Stormwater Management Practices for
Redevelopment
A unique set of practices are commonly used to reduce runoff and pollutant loads from the
redevelopment sector, as shown in Table 3-48. The practices can be applied to address
untreated impervious or pervious areas in the redevelopment sector.
Table 3-48: Example practices for addressing the redevelopment sector
Treat impervious cover
Manage pervious areas
Green Roofs
Rainwater Harvesting, including Blue Roofs
Foundation Planters
Permeable Pavers
Expanded, Compaction-protected Tree Pits
Flexible Rubber Sidewalk Sections for Tree Pits
Urban Bioretention
Bioretention
Conserve and Restore Natural area Remnants
Soil Amendment and Restoration
Reforestation
Conservation Landscaping
Turf Management
Impervious Cover Reduction
Create Functional Bioretention from Elevated
Parking Lot Islands and Traffic Medians
Note: Where surface area is available, typical on-site LID Stormwater practices from the new development sector can be
used. In addition, when feasible on-site practices are not capable of achieving full attainment of predevelopment
hydrology, restoration practices from the existing development areas may help in mitigation. For more detailed information
on each practice, see the practice profile sheets in Appendix 1 of this chapter.
Key considerations in applying these practices are as follows:
• Use a Roof to Street Design Approach. Break the site into smaller drainage areas with a
unique LID solution for each area (e.g., roofs, pedestrian areas, streets, open space and
parking lots). In that manner, Stormwater management is directly integrated into the
3-136
Chapter 3. Urban and Suburban
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
design of buildings, parking lots, hardscapes, open spaces, landscaping, and
streetscapes. That avoids the need for underground structures or consumption of costly
surface real estate for stormwater practices. The basic approach includes
- Managing rooftop runoff through green roofs, water harvesting, disconnection, or
storage and release from foundation planters
- Minimizing surface parking or designing surface parking to reduce, store, and
treat stormwater using permeable pavements, bioretention, or biofiltration (see
San Mateo County 2009)
- Designing urban hardscapes such as plazas, courtyards, and pedestrian areas to
store, filter, and treat runoff using permeable pavers (with storage in the void
space of underlying gravel), stormwater planters, and amenity bioretention areas
- Ensuring that all pervious and landscaping areas in the redevelopment project
are designed for effective stormwater treatment using practices such as soil
restoration, reforestation, and bioretention
- Designing the streetscape to maximize the capture and use of stormwater runoff
by using expanded tree pits, street bioretention, curb cut extensions, and other
green street methods (see City of Portland 2008b; City of Philadelphia 2008; and
San Mateo County 2009)
An example of such a design approach is the redevelopment of an office building at
1050 K Street, NW, Washington, DC, in the downtown business district, shown in
Figure 3-23. Figures 3-24 and 3-25 provide additional redevelopment examples.
• Reduce Real Impervious Cover. Ensure that pervious cover performs hydrologically as if it
were an undisturbed pervious area. Deep tilling and amending soils with compost and other
materials can increase porosity and water holding capacity. In many cases, runoff from
rooftops can be effectively disconnected and drained over such improved pervious areas.
• Identify and Treat Hotspot-Generating Areas. Require that contributing drainage areas
from stormwater hotspots be isolated from the remainder of the site (usually by grading
and drainage) so that the runoff can be fully treated to prevent toxic discharges to
surface water or groundwater.
• Adapt LID to Urban Design. Adapt principles such as Better Site Design (CWP 1998) to
urban environments. Examples include innovative urban parking management solutions
(City of Emeryville 2005), municipal green street specifications (San Mateo County
2009), context-sensitive road design standards providing stormwater treatment in the
right-of-way (MC 2008), and modifications to traditional streetscape standards to use
Chapter 3. Urban and Suburban 3-137
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
street trees as a stormwater filtering device (City of Portland 2008b; Cappiella et al.
2006; Stormwater Magazine March/April 2010).
The potential for green infrastructure to mimic natural systems even in the densest cities is demonstrated at
1050 K Street—a LEED Gold-certified office building in the heart of Washington, DC, on the site of a former
parking lot. The site had been 97 percent impervious. The project design reduced impervious area to 67
percent. Runoff from the property occurs only in a major storm event because of the green infrastructure
practices employed in the building design:
• Two tiers of green roofs retain rainwater falling on the rooftop
• Three bioretention cells in the building plaza retain and treat runoff from adjacent impervious
areas
• A 5,000-gallon cistern beneath the building complements these features by storing any
stormwater that cannot be retained.
• All irrigation water is from the cistern, reducing building water consumption and maintaining
cistern storage capacity.
This suite of green infrastructure practices provides stormwater benefits, an urban oasis for the tenants and
passers-by, and a competitive advantage for the building owners (Lanier 2007).
Photos, courtesy Lu Gay Lanier, The Timmons Group
Figure 3-23. Redevelopment stormwater retrofits at 1050 K Street, Washington, DC, illustrates
practices applicable to federal facilities.
3-138
Chapter 3. Urban and Suburban
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
In 2009 Manassas Park, Virginia, expanded the elementary school, using an existing impervious parking lot
as the site. The new school incorporates many natural educational features, a historic site, and functional
stormwater features. Native plants and no-mow meadow grasses are used to enhance the educational
experience. The post-development runoff is slightly lower than predevelopment conditions. See a video
highlighting the features at http://vimeo.com/chesapeakebay.
A 75,000-gallon rainwater cistern, built to potable water standards, collects rainwater from the entire rooftop
area and is used for toilet flushing and irrigation. It is estimated to conserve 1.3 million gallons of water per
year. An outdoor classroom with semicircular, stepped seating doubles as a stormwater bioretention cell.
Figure 3-24. Manassas Park Elementary School.
Chapter 3. Urban and Suburban
3-139
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
The Yorktown retrofit project serves as a model for residential and business communities demonstrating how
green roofs and other stormwater management designs can be implemented to improve water quality,
decrease erosive stormwater, and conserve flora and wildlife resources in the Chesapeake Bay watershed.
In designing the green roof, structural concerns relative to the 30-year-old building were a major factor in the
decision to use a lightweight building system incorporating waterproofing, root barrier, water retention, and
drainage system in one layer. The 15 pound/square foot capacity had to include all weight associated with
the waterproofing, growing media, water retention system, and mature vegetation (fully saturated and fully
hydrated). The project, including membranes cost $12 per square foot (sf) (for a 4,700-sf green roof system).
It is estimated that the green roof provides a 20 percent reduction in cooling cost and should enjoy a life
expectancy of more than 40 years. Initial reports confirm that 80 percent of the annual rainfall is retained on
the roof, via a hydrogel technology along with the design of the porous growing media. Other storm water
management features consist of rain gardens, a bioswale, and a federally protected biohabitat.
i;,. iilBiji.ii
Source: www.qreenroofs.org/washinqton/index.php?paqe=yorktown
Figure 3-25. Yorktown Square Condominiums, Falls Church, Virginia, successfully implemented a
green roof retrofit.
4.2.1 Practice Integration and Assessment Tools
Effective application of the roof-to-street design approach in the redevelopment sector requires
creative integration of stormwater practices in buildings, courtyards, streetscapes, and parking
lots. Multiple practices are used to treat and reduce runoff from small and different urban
surfaces, using a treatment train approach to help ensure the best performance.
Redevelopment programs should identify opportunities for a range of types and sizes of
redevelopment projects. Practices should be identified that can be encouraged or required for
implementation at sites even below applicability area thresholds.
3-140
Chapter 3. Urban and Suburban
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
Integrating stormwater management practices into design requires overcoming some of the
development s/7os that focus on a single-purpose objective. Landscaping can be designed as
functional; parking lots can be designed with drainage features enabling placement of
bioretention; opportunities have been identified in many formerly single-use designs.
Several tools have been developed to track progress in meeting the performance standards for
the redevelopment sector, and to identify cost-effective combinations of practices at the site.
Such tools include the following:
• A series of spreadsheets that allow the user to break the site into smaller drainage areas
and size and optimize the most appropriate practices for them. For example Emeryville,
California (COE 2005), developed a spreadsheet-based calculator to determine the
proper size of stormwater treatment devices for new development projects
(see http://ca-emervville.civicplus.com/DocumentView.aspx?DID=109). Virginia
Department of Conservation and Recreation (VA OCR 2009a) developed a spreadsheet-
based tool to estimate stormwater volume reduction and pollutant removal (see
www.dcr.virginia.gov/lr2f.shtml).
• Philadelphia uses a series of checklists and worksheets to achieve the same purposes
(City of Philadelphia 2008) (see
www.phillvriverinfo.org/PWDDevelopmentReview/RequirementsLibrary.aspxtf)
Urban communities in the Chesapeake Bay watershed and elsewhere should adapt and modify
such integration tools to meet their unique redevelopment conditions.
Designers might also maximize stormwater green points to obtain green building certifications or
use the performance benchmarks for sustainable stormwater initiatives (ASLA 2009). See the
example in Figure 3-26.
Chapter 3. Urban and Suburban 3-141
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
The Eastern Village Condominiums structure is a redevelopment of a former office building that has been
transformed into 56 condominium units in a thriving urban community. It is the first LEED-certified
cohousing structure. Before construction, the site was more than 90 percent impervious while the new
design decreased the imperviousness of the site to 54 percent. Practices installed at the site include a
green roof, a vegetated courtyard, and rain barrels.
Roof area: 12,330 sf
Planted area: 8,000 sf
Cost: $36/sf (2006)
Source: www.qreenroofs.orq/boston/index.php?paqe=easternwin
Figure 3-26. Eastern Village Cohousing Condominiums HOA, Silver Spring, Maryland, are an
example of redevelopment with stormwater management and amenity value from a green roof.
4.3 Site Evaluations
Site evaluations should be conducted to determine the appropriateness of infiltration practices.
Soils should be evaluated to determine whether the site is subject to brownfield remediation.
Stormwater designers can use the assessments to determine if stormwater runoff can be
infiltrated, soils need to be capped, environmental and utility constraints exist, or natural area
remnants can be protected or restored. The investigations are also useful to map the best
locations for LID practices and how they can be connected as an effective system.
4.4 Planning Documents and Specification Review
Change or supplement planning documents and specifications as necessary to allow the use of
certain redevelopment practices (e.g., rainwater harvesting/plumbing codes, green
3-142
Chapter 3. Urban and Suburban
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
roofs/building codes; green streets/road codes). Some issues that federal facilities deal with are
similar to codes and ordinances of local government, and those local government requirements
could affect facility planning and design. Examples of municipal guides for codes review to help
overcome barriers to LID implementation are EPA's Water Quality Scorecard
(http://cfpub.epa.gov/npdes/greeninfrastructure/munichandbook.cfm) (USEPA 2009f), Better
Site Design: A Handbook for Changing Development Rules in Your Community (CWP 1998)
and NRDC's Out of the Gutter: Reducing Polluted Runoff in the District of Columbia
(Woodworth 2002) (www.nrdc.org/water/pollution/gutter/gutter.pdf).
4.5 Demonstration Projects
Implement demonstration projects to promote and demonstrate green infrastructure techniques.
That approach is proven to promote progress in implementing innovative practices.
4.6 Incentives for Early Adopters
EPA provides examples of program types and municipal case studies in the Managing Wet
Weather with Green Infrastructure Municipal Handbook Incentive Mechanisms (USEPA 2009a).
For municipalities, those can include a wide variety of financial and fee-reduction incentives.
For federal facilities, incentives include awards and recognition programs. In addition, when land
is leased to private entities, requirements for on-site stormwater management should be
included where technically feasible.
4.7 Maximize Urban Forest Canopy
Maximize vegetation and forest canopy across the site to gain incremental stormwater treatment
using expanded tree pits, green roofs, foundation planters, and urban bioretention. Information
on urban forestry practices is in Chapter 2, and in the fact sheet on reforestation/urban forestry
in Appendix 1.
4.8 Amend Compacted Urban Soils
Urban soils are often compacted resulting in poor infiltration rates. Amending the soil with
compost or another soil mixture can significantly increase the infiltration rate for the soils.
Information on soil amendment practices are in Section 5 on turf management, and in the fact
sheet on soil amendment in Appendix 1. Soil amendments can export N and P, in particular just
after installation, so take care to ensure use of low-P-containing soils, and to not offset the
benefit of stormwater retention with nutrient export in larger storm events.
Chapter 3. Urban and Suburban 3-143
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
5 Turf Management
Section 5 of this chapter provides guidance on recommended turfgrass management practices
that can be used to reduce the impacts of developed and developing areas on water quality.
This section contains recommendations that address both the initial design of landscapes and
management practices that apply to the long-term management of areas planted with turf.
Several overall principles guide the development of an effective turf management program.
Ideally, landscapes should be designed to achieve multiple goals, e.g., recreational use,
aesthetics, wildlife habitat, water quality, and public health benefits. Designers should consider
desired end uses, site conditions, maintenance needs, and potential benefits and other impacts
that could result from a given design or set of landscape designs. The design and maintenance
of a landscape, whether it is covered by turf or other vegetation, requires the use of an adaptive
management approach that should be periodically adjusted according to the original vision for
the landscape, changing site conditions, and other factors such as changes in use, local codes,
and ordinances and other societal values that can dictate the desired use of the landscape.
For example, municipalities around the United States are implementing green infrastructure
programs to modify both the built environment and the associated landscapes to reduce
stormwater runoff, urban heat island impacts, air pollution, maintenance costs, and energy
consumption. To simultaneously achieve those goals, many cities and private entities are
actively trying to promote integrated designs that are more sustainable in the long term, less
costly to maintain, more resilient to change, and provide higher levels of environmental
protection and improved community livability.
The use of turf in landscapes has a longstanding history and is desirable in many situations for
playing fields, access to facilities, safe transportation routes, urban open/green spaces, runoff
filtration, and the like. However, all turf does not function equally in terms of use and
performance, nor is turf the optimal vegetative cover for all landscape applications in terms of
water quality protection. This guidance provides recommendations on how to manage different
categories of turf on the basis of management prescription and environmental performance from
a water quality and hydrologic perspective.
The following list of implementation measures provides an overview of the approaches and
practices recommended in this section. For purposes of this guidance, turf refers primarily to
grass grown on lawns and other landscaped areas in suburban and urban areas and not
specifically to sod farms. (Although sod farms are not the focus of this guidance, the turf area
3-144 Chapter 3. Urban and Suburban
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
cover and distribution numbers developed by the Chesapeake Stormwater Network include turf
area cultivated by sod farms in the Chesapeake Bay watershed. For more detail, see Table 3-49.)
Implementation Measures:
Turf Landscape Planning and Design
U-18. Where turf use is essential and appropriate, turf areas should be designed to
maintain or restore the natural hydrologic functions of the site and promote
sheet flow, disconnection of impervious areas, infiltration, and
evapotranspiration.
Turf Management
U-19. Use management approaches and practices to reduce runoff of pollutant
loadings into surface and ground waters.
U-20. Manage turf to reduce runoff by increasing the infiltrative and water
retention capacity of the landscape to appropriate levels to prevent pollutant
discharges and erosion.
U-21. Manage applications of nutrients to minimize runoff of nutrients into
surface and ground waters and to promote healthy turf
• Where appropriate, consider modifications to operations, procedures,
contract specifications and other relevant purchasing orders, and facility
management guidance to reduce or eliminate the use of fertilizers
containing P
U-22. Manage turf and other vegetated areas to maximize sediment and nutrient
retention.
U-23. Reduce total turf area that is maintained under high-input management
programs that is not essential for heavy use situations, e.g., sports fields and
heavily trafficked areas.
U-24. Convert nonessential, high-input turf to low-input or lower maintenance turf
or vegetated areas that require little or no inputs and provide equal or
improved protection of water quality.
U-25. Use turf species that reduce the need for chemical maintenance and
watering, and encourage infiltration through deep root development.
U-26. Conduct a facility or municipal wide assessment of the landscaped area
within the facility property or jurisdiction. This assessment should include
• A map of the jurisdiction or facility, including the identification of all turf
and other landscape areas
Chapter 3. Urban and Suburban 3-145
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
• An inventory or calculation of the total turf and other landscape area in
acres or hectares using GIS techniques or other methods
• An evaluation to determine essential and nonessential turf areas
• Identification and delineation of all high-input, low-input, and no-input
turf areas
• An evaluation of turf management activities and inputs, preferably by
turf category or significant turf area within the facility or jurisdiction
• An assessment of landscape cover type benefits such as pollution load
reductions and resource savings, e.g., water and energy that are provided
by each landscape cover type
• An assessment of landscape cover type health, infiltrative and pollutant
loading capacity and opportunities to increase soil health to promote the
infiltrative capacity of turf and landscape areas
• An assessment of surface water and groundwater loadings related to
high-input, low-input, and no-input turf area
U-27. Develop a management plan that contains
• An analysis of options to reduce or eliminate nonessential turf or convert
essential turf to low-input turf that performs optimally from a water
resource protection perspective
• An analysis of turf areas to identify opportunities to maximize water
quality benefits of landscapes in regard to runoff, in-stream flows,
infiltration, groundwater recharge and sediment, nutrient and pathogen
loadings
• A landscaping approach that integrates turf management within the
context of natural resource and habitat plans
• Stated goals and objectives regarding the reduction of turf related inputs
(water, fertilizers, pesticides, fossil fuels) and maximizing water resource
benefits on a facility- or municipality-wide basis
• An analysis of options to reduce potable water use by using cultural
practices, hardy cultivars, or recycled water or harvested runoff
• An identification of areas where soil amendments can be used to enhance
soil health and the infiltration capacity of the soils
• Areas of turf that could be used to manage runoff
• Areas of turf that could be replaced by lower maintenance cultivars or
other grasses such as switch grass
3-146 Chapter 3. Urban and Suburban
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
• A training program for landscaping personnel
• An implementation schedule
• An annual landscaping inventory and progress report
U-28. Develop and implement ongoing public education and outreach programs
Bay-friendly lawn, landscape, and turf management. Programs should target
behavior change and promote the adoption of water quality friendly practices
by increasing awareness, promoting appropriate behaviors and actions,
providing training and incentives. Impact and effectiveness evaluation should
be incorporated into such outreach and education programs.
5.1 Background
In the Chesapeake Bay watershed, turf has been estimated to cover 3.8 million acres or
9.5 percent of the total land area. Turf, in terms of total area, is now the number one cultivated
ground cover grown in the Chesapeake Bay watershed (Chesapeake Stormwater Network
2010). Tables 3-49, 3-50, and 3-51 adapted from the Chesapeake Stormwater Network (2010)
reflect estimates of turf cover by state, distribution by landscape category or sector and by
county with the highest turf density. Figure 3-27 provides a graphic illustration of turf density by
county in the Chesapeake Bay watershed that appears to show a positive relationship between
degree of urbanization and turf cover density.
Table 3-49. Year 2001 turf cover estimate using a GIS and satellite data
State
MD
VA
PA
DC
DE
NY
WV
Total
Land acres in
bay watershed
5,639,428
13,706,037
14,345,262
38,956
450,384
3,983,079
2,288,363
40,451,509
Urban3 turf
acres
1,007,269
988,291
900,803
16,071
31,337
160,788
75,515
3,180,074
Exurbanbturf
acres
298,476
135,792
158,212
2,320
3,648
32,982
12,425
643,855
Total turf acres
1,305,745
1,124,083
1,059,015
18,391
34,985
193,770
87,940
3,823,929
Percent land
area with turf
23.15%
8.20%
7.38%
47.21%
7.77%
4.86%
3.84%
9.45%
Source: Chesapeake Stormwater Network 2010.
a. Urban area includes impervious and non-forested pervious surfaces in industrial, commercial, and residential areas with
lot sizes generally less than 2 acres.
b. Exurban areas represent all non-urban lands. The urban recreational grass land cover class was solely used to identify
turf grass in exurban areas.
Chapter 3. Urban and Suburban
3-147
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
Table 3-50. Distribution of turf grass by sector in Maryland, Virginia and New York (percent)
Turf sector
Home lawns
Apartments
Roadside Right-of-Way
Municipal Open Space
Parks
Commercial
Schools
Golf Course
Churches/Cemeteries
Airports/Sod farms)
1 989-1 998a
70
ndb
10
7
3.5
nd
3
2.5
2
1
MD 2005
82.6
0.6
4.3
3.5
1.9
nd
3.4
1.4
1.2
1.1
VA 2004
61.6
nd
17.5
6
2.5
5
2.9
2.2
1.4
0.9
NY 2005
82.1
0.8
nd
nd
1.9
0.3
1.6
3
1.1
0.6
Source: MDASS 2006, VADACS 2006, and NYASS 2004, as reported in Chesapeake Stormwater Network
2010.
a. Average of three states: MDASS (1996), VAASS (1998) and PAASS (1989)
b. nd = no data because the indicated turf sector was not sampled or estimated
Table 3-51. Counties in the Bay watershed with the highest turf grass cover based on GIS
Jurisdiction/county
Montgomery
Baltimore
Prince George's
Lancaster
Fairfax
York
Frederick
Anne Arundel
Carroll
Harford
Howard
Luzerne
Washington
Dauphin
Henrico
State
Maryland
Maryland
Maryland
Pennsylvania
Virginia
Pennsylvania
Maryland
Maryland
Maryland
Maryland
Maryland
Pennsylvania
Maryland
Pennsylvania
Virginia
Turf acres
140,272
136,456
121,008
119,615
116,932
110,564
96,309
93,081
85,114
77,084
66,239
63,887
61,527
56,347
55,643
Total land acres
317,420
379,708
306,846
605,215
251,360
577,749
424,381
260,832
286,896
272,524
160,906
486,405
295,043
337,650
150,305
Percent turf
44.20%
35.90%
39.40%
19.80%
46.50%
19.10%
22.70%
35.70%
29.70%
28.30%
41 .20%
13.10%
20.90%
16.70%
37.00%
Source: Chesapeake Stormwater Network 2010.
3-148
Chapter 3. Urban and Suburban
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
Distribution of Turf Grass
in the Chesapeake Bay Watershed
(yr. 2000)
Legend
| | US_DetailedStates
| | Chesapeake Bay
Counties/ cities
Turf grass (acres)
| | 0 - 30,000
30,001-60,000
60,001-90,000
90,001 -120,000
120,001-150.000
Source: Chesapeake Stormwater Network 2010
Figure 3-27. Distribution of counties with high turf cover in the Chesapeake Bay watershed.
Chapter 3. Urban and Suburban
3-149
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
The increase in turf area reflects a national trend according to Robbins and Birkenholt (2001)
who examined turf in terms of land use/cover changes and the "expansion of high-input,
monocultural, lawn landscapes," that "bring with them inputs of insecticides, herbicides and
fertilizers...expanded use of lawn maintenance tools" such as mowers and "changes in soil
profile, stormwater runoff, water consumption, micro-fauna diversity, energy use, air quality and
habitat impacts." Fender (2008) reported that nationally, "There are an estimated 50 million
acres of maintained turfgrass in the United States on home lawns, golf courses, sports fields,
parks, playgrounds, cemeteries, and highway rights-of-way." Milesi et al. (2005) reported that
nationally, 15.8 million acres (31.6 percent) of cultivated turf is in home lawns.
Turf that is properly located, selected, and maintained can provide water quality benefits,
especially when used to reduce the effects of impervious surface cover (Beard and Green 1994;
Carrow et al. 2008). As noted earlier in Sections 1-3 of this chapter, the use of practices that
can reduce the effective impervious surface area of a developed area is encouraged.
Landscapes planted with turf can effectively be used to treat runoff in grassed swales and filter
strips and are commonly used along transportation systems and the borders of agricultural
lands to reduce runoff pollutant loadings. Schueler (1987) described how such grassed systems
can be designed for the catchment and filtration of runoff. For more information regarding the
benefits of grass swales to manage runoff from agricultural fields, see Chapter 2. Grass swales
also have proven to be effective in treating pollutants in highway runoff (Davis 2009).
The conversion of native landscape to turf, however, inevitably results in ecosystem-level
changes regardless of how the turf is managed. For example, the conversion of native forest or
native vegetation to turf or other cultivated landscapes can cause reductions in
evapotranspiration; increases in runoff volumes, velocities and duration of flows; increases in
runoff temperature; microclimate changes; decreased infiltration; changes in soil health and
biota; and loss of species diversity and habitat. Infiltration tests conducted in a North Carolina
watershed found that a medium-aged, pine-mixed hardwood forest has a mean final constant
infiltration rate of 12.4 inches per hour; however, when the forest understory and leaf litter were
removed, the resultant lawn had a mean infiltration rate of 4.4 inches per hour (Kays 1980).
Dierks (2007) discussed the hydrologic benefits of native landscapes in his publication Not all
Green Space is Created Equal and made the point that the heterogeneous nature of native
landscapes typically results in stable ecological systems that do not require the level of inputs
that managed turf typically requires. Dierks used Table 3-52 (adapted from Bharati 2002) and
Figure 3-28 to emphasize the benefits of native landscapes and to compare the differences in
hourly infiltration rates of different vegetative cover types such as silver maples and switch
grasses and the differences in grass root depth and structure between native grasses and
Kentucky bluegrass. Note, however, that changes in infiltration rate and soil health also can be
due to land disturbances that occur during the development process. Typical land clearing
practices often strip fragile topsoils from the site and compact the subsoils. In such situations,
3-150 Chapter 3. Urban and Suburban
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
soil amendments can be used to restore soil health, and turf is often an appropriate cover to
prevent erosion and reduce runoff related problems.
Table 3-52. Average hourly infiltration rates from multispecies buffer (adapted from
Bharati et al. 2002)
Treatment
Jun
Aug
Oct/Nov
Avg
(cm/hr)
Silver Maple
Grass Filter
Switchgrass
Bean
Corn
Pasture
Sandy Loam
Silty Clay Loam
38
29
27
8
3
2
46
20
8
9
5
4
30
25
21
13
3
3
38
25
19
10
4
3
1.1*
0.3*
Figure 3-28. Comparison of native prairie and turf grass root and shoot growth.
Chapter 3. Urban and Suburban
3-151
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
Turf type and management practices also influence the behavior of turf in terms of changes in
runoff hydrology and pollutant loadings. High-input turf is irrigated, frequently mowed, fertilized
at rates of 3 to 5 Ibs N/1,000 ft2/year, and/or treated with pesticides as part of its regular
maintenance regime. Low-input turf has little or no irrigation, is frequently mowed, fertilized at
lower rates (1-2 Ibs N/1,000 ft2/year), and has low pesticide application. No-input turf is not
irrigated, fertilized, or treated with pesticides and in some cases is mowed infrequently or not at
all (Wilbe 2010).
5.2 Turf-Related Impacts
The following section contains descriptions of the main water quality related effect that can
result from the cultivation and maintenance of turf.
5.2.1 Fertilizer Applications
The rate at which fertilizer is applied to home lawns and commercial and institutional
landscaping varies depending on the level of maintenance (high or low input) and who is
maintaining it (homeowners or lawn care companies), as shown in Table 3-53.
Table 3-53. Lawns managed by homeowners versus other lawn services
Comparative chemical application rates in pounds/acre/year in Maryland
Chemical
N
P
Pesticides
Cropland3
184
80
5.8
Golf fairway
150
88
37.3
Greens
213
44
45.1
Home lawn
(do-it-yourself)
44-261
15
7.5
Home lawn
(lawn service)
194-258
no data
no data
Source: http://www.cwp.org/Resource Library/Center Docs/PWP/ELC PWP129.pdf.
Note: a. Corn/soybean rotation
A residential lawn care survey, undertaken by Law et al. (2004) as part of the Baltimore
Ecosystem Study, assessed fertilizer application rates and the factors that affect those rates to
estimate N input from lawn care practices in urban watersheds. The results indicated a wide
range in the rate of fertilizer N applied by homeowners and lawn care companies, averaging
1.99 lb/1000 ft2/year (about 88 pounds per acre) with a standard deviation of 1.81 lb/1000
ft2/year. Factors that affected fertilizer application rate include social economic factors (market
value of the house, age of development) and soil characteristics (soil bulk density and soil N
content). A 2010 inspection of information provided on lawn fertilizer products sold in gardening
and appliance stores in the Chesapeake Bay watershed found that the manufacturers typically
recommend four fertilizer applications annually. On the basis of the manufacturers' application
3-152
Chapter 3. Urban and Suburban
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
recommendations, the typical user could apply the products at approximately 140 pounds
per acre.
Schueler (2000d) estimates that home lawns account for 70 percent of total turf area in the
Chesapeake Bay watershed, half of which is maintained as high-input turf. The remaining
30 percent of total turf area is public turf, including parks, golf courses, schools, churches,
cemeteries, median strips, utility corridors, and office parks, of which one-third is estimated to
be maintained as high-input turf. Applying those estimates to the estimated 3.8 million acres of
turf in the Chesapeake Bay watershed yields 1.71 million acres maintained as high-input turf
and 2.09 million acres maintained as low-input turf. Annual N applied to turf areas in the
watershed, estimated using the definitions of high-input and low-input turf presented above, is
approximately 389 million pounds of N per year.1 Such a magnitude of N use in the watershed
underscores the need for management practices that reduce risk, ranging from high-quality
nutrient management planning and implementation by institutions to turf reduction actions, to
prevent excess N from entering the Bay.
5.2.2 Irrigation
Irrigation of turf grass contribute to water shortages and overwatering can lead to poor turf
health and runoff problems. Turfgrass-dominated landscapes can require the use of more water
than landscapes consisting of a mix of groundcovers, shrubs, and trees. Grass generally
consumes eight units of water compared to the same area of trees (five units), and shrubs and
ground covers (four units) (Foster 1994).
5.2.3 Energy and Air Quality
Lawns that are mowed have energy costs and air quality impacts, depending on the type of
mower used. According to Paul Tukey, founder of SafeLawns.org, a Maine-based nonprofit
dedicated to minimizing the environmental effect of lawn care, gas-powered mowing, weed-
whacking and edging a modest-sized lawn (625 square feet) for one month would use
approximately 6 kilowatt hours or 0.2 gallons of gas (Mosko 2009).
Gas-powered lawn tools are also significant sources of smog and carbon monoxide. According
to Clean Air Lawn Care's Clean Lawn Calculator (http://www.cleanairlawncare.com/calculator/),
assuming conditions consistent with Maryland or Virginia with 36 mows per year for 1.7 million
acres of high-input turf in the Chesapeake Bay watershed, gas-powered lawn equipment
1 For this calculation, high-input turf is assumed to have an N application rate of 4 Ib N/1000 ft2/year, which is the
midpoint of the high-input range defined previously. The N application for low-input turf is assumed to be
1 Ib N/1000 ft2/year, which is the low end of the 1 to 2 Ib N/1000ft2/year range to account for homeowners who do not
apply any fertilizer.
Chapter 3. Urban and Suburban 3-153
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
produces 3,891,470,584 annual pounds of air pollution. That number can be reduced to
2,233,912,919 by using electric lawn equipment (powered by conventional energy) because
electric mowers emit 3,300 times less hydrocarbons, 5,000 times less carbon monoxide, and
one-fifth as much smog-forming N oxides as gas lawn mowers. Self-powered push mowers do
not generate any air pollution, and they have the added benefit of mulching and depositing
grass clippings on the lawn.
5.3 Turf Management Strategies, Practices, Resources
and Examples
To ensure that turf performs optimally from a water-quality as well as a broader environmental
perspective, the following turfgrass cultural practices should be promoted and encouraged.
5.3.1 Turf Landscape Planning and Design
The design of landscapes should be considered within the context of the site, facility and
watershed. The use or degree of use of turf on a site will be dependent on a number of factors
such as existing vegetative cover, soils, geology, intended use of the site and other
environmental factors such as water quality and wildlife habitat protection. In areas where the
natural vegetative cover, e.g., mature deciduous hardwood forest, will be initially developed, the
designer should strive to retain as much natural vegetative cover as possible within the design
context of the new development to preserve site hydrology, soils and existing wildlife habitat and
reduce the need to restore, plant and manage disturbed soils. Lands regardless of vegetative
cover type that are obviously degraded should be managed differently and can require
restoration. For example, redevelopment and retrofit projects often present the designer with a
much different set of factors and challenges to contend with given the existing site conditions.
Soils in heavily urbanized areas and brownfields are often very poor, compacted, and not good
media for growing and sustaining healthy plants; nor do they promote the level of infiltration
necessary to reduce runoff, prevent erosion, filter pollutants maintain stream baseflow and
aquifer recharge. Turf, in such conditions, might be a suitable choice for the designer to help
restore the hydrologic function of the urban landscape, reduce pollutant loadings resulting from
erosion of degraded soils, and provide urban open spaces. Designers also might want to
consider laying vegetation using turf or other groundcovers and shrubbery and trees to increase
the benefits of vegetation on runoff interception, evapotranspiration and nutrient uptake, and
wildlife habitat.
Rating systems or metrics such as the Sustainable Sites Initiative (SSI) Guidelines and
Performance Benchmarks 2990 might be useful in assessing designs to determine how well the
designs meet multiple objectives for site sustainability in terms of site hydrology, vegetation,
3-154 Chapter 3. Urban and Suburban
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
soils, human factors, and such. More information on SSI and similar rating systems is at the
following sites:
• Sustainable Site Initiative Guidance and Performance Benchmarks 2009
(http://www.sustainablesites.org/report)
• Leadership for Energy and Environmental Design, LEED® for New Construction & Major
Renovations (http://www.usgbc.org/ShowFile.aspx?DocumentlD=1095)
5.3.2 General Turf grass Best Cultural Practices
The following list of practices can be used to promote healthy turf that provides the desired use
and environmental performance (Wilbe 2010). More details and examples of specific turf
management practices are provided in subsequent sections.
Soil improvement
• Mulch clippings back into the grass. Recycling clippings onto lawns improves soil
organic content and returns nutrients to the soil.
• Aerate compacted sites annually. Aeration loosens soil to improve water infiltration, air
exchange, and plant rooting.
• Apply nutrients, as appropriate according to management goals, in spring, fall, or both,
when roots are actively growing. Feeding stimulates root development, which in turn
adds more organic matter to improve soil qualities.
• Mulch deciduous tree leaves into lawn areas. Directly mulch leaves into turfgrass where
they will degrade into the turf canopy and add soil organic matter.
Preserve or enhance stand density
• Mow at heights of 3 inches and higher. Grass maintained at higher heights will support a
larger root system to best sustain itself especially during times of stress. Taller grass can
also help to naturally crowd out invasive weeds.
• Use soil and turf enhancement practices to increase turf density as appropriate for use,
location, and environmental goals.
Water conservation
• Avoid watering during drought periods. Grass can go dormant in months when water is
scarce and safely recover when rains return.
Chapter 3. Urban and Suburban 3-155
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
• Mow high to capture more water. Taller grass maintains denser roots to access more
available soil moisture throughout the year.
• Feed in the spring and/or fall months. Feeding in the spring allows grass to grow deeper
roots and develop reserves prior to summer stress periods. Fall feeding helps grass
recover from any damage
Fertilizer care
• Feed only when grass is actively growing. Avoid feeding during periods of drought or
when the ground is frozen (December-March).
• Apply fertilizer only to lawn areas. Sweep any material from paved impervious surfaces
back onto lawns. Avoid fertilization runoff or deposition into waterbodies.
• Use proper fertilizer spreaders that have been calibrated. Use drop or rotary spreaders
with side guards to keep fertilizers off of impervious surfaces
• Avoid fertilization before heavy rainfalls
Clippings management
• Sweep clippings off of impervious surfaces to avoid discharges into surface waters.
The Golf course industry provides a good example that illustrates the benefits of outreach and
education efforts that promote the implementation of better practices. The industry—recognizing
its role in promoting golf course designs and management practices that can be used to
manage turf in an environmentally sound manner—developed golf course design and
management principles and research and educational programs to promote that agenda.
The Golf and Environment Initiative was developed to further promote those goals. More
information is at http://www.golfandenvironment.com/.
Numerous states and communities are also addressing the need to promote consistency and
improved practice in terms of golf course management. The Golf Course Water Resources
Handbook of Best Management Practices—recently produced by LandStudies, Inc., and the
Pennsylvania Environmental Council, funded by the Pennsylvania Department of Environmental
Protection (2009)—is one example of such a tool. The handbook pulls from the knowledge and
experience of many golf course superintendants and provides a nice background on the
importance of mapping, irrigation and water reuse practices, selecting and applying chemicals
and fertilizers knowledgably, increasing the use and area of native plants and naturalized areas,
as well as other topics. The document reviews 18 BMPs specific to golf courses. The document
is at http://www.pecpa.org/files/downloads/Golf BMP Handbook 3.pdf.
3-156 Chapter 3. Urban and Suburban
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
Public education is also an important aspect of promoting better turf management practices. A
good example of a program developed to change public behavior and promote better cultural
practices to manage turf is Austin, Texas', Grow Green program. The city recognized the need
to protect the Edwards aquifer and surface water quality from nutrient impairments and
conducted a lawn fertilization and management study to reevaluate common fertilizer
recommendations. As a result, the city recommended new residential lawn fertilization practices
that change those promoted statewide for the last 20 years. Those recommendations were
developed within the context of a comprehensive outreach program that educates the public
about proper turf management practices. This program is a partnership among extension
offices, retailers, nurseries, and government (state, municipal and federal). More information is
at: http://www.ci.austin.tx.us/growgreen/.
5.3.3 Fertilizer Management
Soil tests are commonly used to manage fertilizer applications to optimize application rates and
reduce runoff and leaching. Determining the nutrient N and P needs of lawns by the soil
concentrations of P might not adequately predict proper application rates or potential for runoff
or leaching of nutrients. Furthermore not all soil tests analyze for soil N content.
N should be applied on the basis of established requirements for grass species, season of
growth, and intended use. Ideally fertilizers should be applied on the basis of the limiting nutrient
and concentrations of nutrients determined by soil testing and local experience and research
recommendations for the species being cultivated. Soldat et al. (2008) examined soil P
concentrations in New York State and reported that their results suggest that "soil testing will not
be an effective tool to predict runoff from turfgrass areas across the range of soil P levels
common to New York State." Spreaders used to apply the fertilizer should be carefully
calibrated to ensure even application at prescribed rates. The timing and methods of fertilizer
application are also important. Lawn fertilizer should be applied in the early or middle spring and
in the fall when turfgrass absorbs the most nutrients; fertilizer should never be applied when the
ground is frozen (Wilbe 2010). Weather is also a consideration; fertilizer should not be applied
during or before wind or rainstorms to prevent pollution of air and surface runoff. The type of
spreader used can also reduce pollution; drop spreaders or rotary spreaders with a side guard
help to keep fertilizers on the lawn and off impervious surfaces (Wilbe 2010). To determine
application recommendations, refer to local guidance.
A number of researchers have demonstrated a connection between proper N fertilization,
increased infiltration and reductions in runoff volume and P losses in runoff. (Easton and
Petrovic 2004; Kussow 2008). Increasing plant density through fertilization can be a means to
reduce runoff velocity and promote infiltration. Soldat and Petrovic (2008), however, also noted
that, "Sediment losses from turf areas are negligible, generally limited to establishment, but
Chapter 3. Urban and Suburban 3-157
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
runoff and leaching losses vary from inconsequential to severe depending on rate, source and
timing of fertilizer application," and "Soil properties were found to have a larger effect on runoff
volume than vegetative properties." Areas where turf is exists or is planned should be evaluated
to determine whether fertilization and soil improvements can improve runoff management
performance.
Some communities have implemented policies to restrict fertilizer application or prohibit
P-containing fertilizers in watersheds that are sensitive to P enrichment. The following are
examples of such types of policies.
• Chesapeake Bay Program Memorandum of Understanding (MOU): On September 22,
2006, the Chesapeake Executive Council, Headwater State Jurisdictions, and members
of the lawn care product manufacturing industry signed an MOU that was intended to
achieve a 50 percent reduction in the pounds of P in do-it-yourself lawn care products by
2009 (as compared to a 2006 base year). The MOU further committed the signatories to
reduce N nutrient losses by recommending possible changes in product content, form, or
application method, as well as develop outreach materials to educate the general public
on the use of fertilizers. As a result, the industry achieved a 76 percent reduction in P
before 2010, with elimination of P from all maintenance products scheduled for 2012;
introduction of soil testing for homeowners; adoption of new applicators with a side
guard that prevents application to hard surfaces as a standard feature; and education
and outreach (radio public service announcements, print media, improved labeling, and
point of purchase education). In addition, all lawn fertilizers now contain slow-release N
and limited amounts of soluble N. Finally, a 32 percent reduction in N application rates
and overall N pounds sold and used has been achieved compared to 2006.
• Annapolis, Maryland, recently became the first municipality in the Chesapeake Bay
watershed to adopt an ordinance banning the use of fertilizer that contains P. Since
January 1, 2009, residents have been required to use only P-free fertilizer, except in
gardens, on newly established turf, and in cases where a soil test shows a P deficiency.
For more information, see
www.annapolis.gov/upload/images/government/council/Adopted/o1008.pdf.
• The New Jersey Department of Environmental Protection (NJDEP) is mandating that
more than 100 New Jersey municipalities adopt local ordinances prohibiting the use of
fertilizers containing P except under special circumstances (see ordinance details at
www.state.ni.us/dep/watershedmgt/DOCS/TMDI-/FertilizerApplication Model
Ordinance.pdf). The state is also working to reduce fertilizer application statewide. In
April 2008 NJDEP signed an MOU with two major fertilizer producers to reduce the
amount of P in their lawn fertilizer products, distribute these products in garden centers
statewide, and work with NJDEP to develop strategies to educate the public about
3-158 Chapter 3. Urban and Suburban
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
proper selection and use of lawn fertilizer. For more information, see Recent Partnership
Limits Phosphorus in New Jersey Fertilizer, on page 12 of Nonpoint Source News-Notes
issue 86, at www.epa.gov/NewsNotes/pdf/86issue.pdf (USEPA 2009b). To date, a
50 percent reduction in pounds of P sold in the state has been achieved compared to
2006 levels, and a workgroup has been established to support the Healthy Lawns &
Clean Water initiative. The Scotts Miracle-Gro Company received an Honorable Mention
in the Governor's Environmental Excellence Awards in 2009 for achieving a 70 percent
statewide reduction of P sold in the state and for execution of Healthy Lawns & Clean
Water outreach materials.
• Township of Jefferson, New Jersey: Wthin the township, no person, firm, corporation, or
franchise is to apply liquid or granular fertilizer containing P. No lawn fertilizer of any kind
is to be applied on frozen ground or within 10 feet of a body of water, including wetlands.
http://www.ieffersontownship.net/Cit-e-Access/news/index.cfm?NID=3762&TID=4&iump2=0
• Montville Township, New Jersey: Adopted July 2008, applying fertilizer is prohibited
during a runoff-producing rainfall or before a runoff-producing rainfall is predicted to
occur. Fertilizer application is also prohibited when soils are saturated and fertilizer can
move off-site. Application is further prohibited on impervious surfaces, within 25 feet of a
waterbody, and more than 15 days before the start or at any time after the March 15 to
October 31 growing season. P-containing fertilizer is strictly prohibited anywhere
outdoors at any time except where demonstrated to be necessary for the specific soils
and target vegetation, as noted by Rutgers Cooperative Research and Extension's
annual fertilizer recommendation.
http://www.montvilleni.org/index.php?option=com content&task=view&id=487
• Suffolk County, New York, Fertilizer Prohibition: A new law prohibits lawn fertilizer
applications from November 1 to April 1 to prevent N runoff from frozen ground. The law,
which also requires retailers to post signs near fertilizer displays advising customers of
the date restrictions, took effect in January 2009. Violators, whether landscapers or
homeowners, risk fines of $1,000. Licensed landscapers are required to participate in a
4-hour, county-sponsored session administered by the Cornell Cooperative Extension to
renew their licenses. For more information, see
http://www.nvtimes.com/2009/03/15/nvregion/long-
island/15fertilizerli.html?pagewanted=2& r=1
• Highland Park, Illinois, Phosphorus-Based Fertilizer Ordinance: The Ordinance prohibits
the application of fertilizer containing P to any area within city limits unless the user
meets one of the three allowable circumstances contained in the ordinance. For
example, the fertilizer containing P can be used in areas where the ambient P content is
below the median P area for typical soils or the fertilizer is used under a tree canopy.
Chapter 3. Urban and Suburban 3-159
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
The ordinance further prevents the retail sale of fertilizer containing P within city limits.
For more information, see http://www.citvhpil.com/pdf/Phosphorus-
BasedFertilizerOrdinance.DOC
• Wisconsin Phosphorus Ban: In April 2009, Wisconsin Governor Doyle signed the Clean
Lakes bill (2009 Wisconsin Act 9). The bill established a statewide law prohibiting the
display, sale and use of lawn fertilizer containing P, with certain reasonable exceptions
(e.g., when establishing grass or when a soil test shows that P is needed). The law takes
effect in April 2010, which gives retailers time to prepare. Although retailers will not be
permitted to display turf fertilizer that is labeled as containing P, they may post a sign
advising customers that turf fertilizer containing P is available upon request for qualified
uses. The prohibition does not apply to the following: the use of manure that is
mechanically dried, ground, or pelletized, or to a finished sewage sludge product; the
use of fertilizer that contains P to establish grass during the first growing season; the
application of fertilizer where soils are deficient in P; and agricultural land. Violators can
be required to forfeit not more than $50 for a first violation and not less than $200 nor
more than $500 for a second or subsequent violation. For more information, see
http://www.legis.state.wi.us/2009/data/AB-3.pdf.
• Dane County Wisconsin: As of January 2005, no person in Dane County could apply
lawn fertilizer labeled as containing anything more than 0 percent P. Restrictions on lawn
fertilizer application also include applying any type of fertilizer on frozen or impervious
surfaces, http://www.danewaters.com/management/phosphorus.aspx
• Minnesota Fertilizer, Soil Amendment, and Plant Amendment Law: Minnesota enacted a
statewide law in 2005 prohibiting the use of P lawn fertilizer unless new turf or lawn is
being established, a soil test shows a need for P, or P is being applied to a golf course
or sod growing area by trained staff. When such situations do not exist, state law
requires P-free lawn fertilizer to be used. For more information about the law, see
http://www.mda.state.mn.us/protecting/waterprotection/phoslaw.aspx.
• Buffalo, Minnesota: Effective in 2000, lawn fertilizers were not to be applied on frozen
ground, specified as being between November 15 and April 15. And at no time can any
person, firm, corporation, or franchise apply liquid or granular fertilizer within the city
limits that contains phosphates. Fertilizer application is prohibited on impervious
surfaces and on surfaces within drainage ditches or waterways or within 10 feet of a
water resource. http://www.ci.buffalo.mn.us/Admin/CitvCode/1056.htm
• Sanibel City, Florida: With respect to turf and landscape plants, fertilizers cannot contain
more than 2 percent P or more than 20 percent N, with 70 percent of the N required to
be slow release. Applications are maxed out at one pound of N per 1,000 square feet,
3-160 Chapter 3. Urban and Suburban
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
for a total of 4 pounds of N per 1,000 square feet in any one year. Fertilizer can be
applied up to six times in one year to a single area. Further, no fertilizer is to be applied
on impervious surfaces or within 25 feet of a body of water. Retail businesses were
required to post notices about the new regulation near the fertilizer to inform customers.
http://www.sanibelh2omatters.com/documents/CITY%20APPROVES%20ENVIRONME
NTALLY%20FRIENDLY%20REGULATIONS%20FOR%20FERTILIZER%20USE%20O
N%20ISLAND.pdf
• Bellingham, Washington, Municipal Code: The city's municipal code contains restrictions
pertaining to commercial P-based fertilizer. The municipal code prohibits the application
of commercial fertilizer to residential lawns or public properties within the Bellingham city
limits area of the Lake Whatcom watershed, either liquid or granular, that is labeled as
containing more than 0 percent P or other compounds containing P, such as phosphate,
except when applied to newly established turf or lawn areas in the first growing season.
In addition, the municipal code prohibits applying fertilizer to frozen ground and
impervious surfaces, and imposes requirements for cleanup of fertilizer that is applied,
spilled, or deposited on impervious surfaces. Bellingham's Municipal Code is at
http://www.cob.org/web/bmcode.nsf/srch/B5D4E84B824F05EB882561D6006019737Qp
enDocument.
• Whatcom County, Washington: As of April 2005 for Lake Whatcom and June 2007 for
Lake Samish, using commercial fertilizers containing P on residential lawns or on public
agency properties in the Lake Whatcom watershed is prohibited. Further, no commercial
fertilizer of any kind is allowed to be applied on frozen or impervious surfaces.
http://www.mrsc.org/mc/whatcom/Whatco16/Whatco1632.html
A few fertilizer restrictions have been in place for long enough to measure results. The following
are two studies of the effectiveness of fertilizer ban policies in the Midwest.
• Reduced River Phosphorus Following Implementation of a Lawn Fertilizer Ordinance
(Ann Arbor, Michigan): As part of its efforts to comply with a state-imposed P TMDL to
reduce 50 percent of P discharges to the Huron River, the city of Ann Arbor enacted an
ordinance that went into effect in 2007 to limit P application to lawns. The estimated
effect of full compliance was a 22 percent reduction in P entering the river. The study
indicates that after the first year of data collection and analysis, statistically significant
reductions were documented for total P and, to a lesser degree, for dissolved P for every
month from May to September. The research team states, "with a considerable degree
of confidence that P concentrations were lower in 2008 at experimental sites compared
with the reference period (2003 to 2005) and that the reductions were coincident with a
city ordinance restricting use of lawn fertilizers containing phosphorus." However, the
study does not conclude that those reductions were caused by enacting the ordinance,
Chapter 3. Urban and Suburban 3-161
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
but shows that a correlation exists between reductions in P and the ordinance (Lehman
et al. 2009). http://www.umich.edu/~hrstudy/Reports/LRM 08-40 web.pdf.
• Effectiveness of Minnesota Phosphorus Lawn Fertilizer Law: The Minnesota Phosphorus
Lawn Fertilizer Law directed the Minnesota Commissioner of Agriculture to report in
2007 on the effectiveness of P lawn fertilizer restrictions. The report indicates that
various forms of P-free fertilizers were being sold in stores across the state. For
example, the state polled 87 stores and found that in 97 percent of those stores, P-free
lawn fertilizer was being retailed. In addition, the report found that the law has reduced
the amount of fertilizer containing P that was being used. The report showed a reduction
of 141 tons of fertilizer used or 48 percent of use between 2003 and 2006. The law has
not increased consumer cost for fertilizer and has generally gained consumer support.
Additionally, since the law's inception, manufacturers have been able to adapt to the law
and produce new P-free fertilizer products. Therefore, the change has also expanded
the manufacturer's market for P-free lawn fertilizer in other areas concerned with water
quality, including the Chesapeake Bay region, Florida, Michigan, Wisconsin, and other
states. The report, however, documents only consumer use and manufacturer
development and retail and does not look at the effects on water quality or turf
management. It recommends further research to expand on those areas. For more
information, see the Minnesota Phosphorus Lawn Fertilizer Law:
http://www.mda.state.mn.us/protecting/waterprotection/phoslaw.aspx and the Minnesota
Effectiveness Report of Phosphorus Lawn Fertilizer Law:
http://www.mda.state.mn.us/en/sitecore/content/Global/MDADocs/protecting/waterprotec
tion/07phoslawreport.aspx.
5.3.4 Pesticide Management
Pesticides in urban runoff have been well documented in monitoring studies conducted by the
United State Geological Survey (USGS, 2007). In addition, the Center for Watershed Protection
summarized studies in two articles that indicated that urban land uses were sources of
pesticides into surface waters (Schueler 2000b, 2000e).
Pesticide use should be managed to reduce applications via spot applications and the use of
integrated pest management techniques (IPM). The use of combined fertilizer and pesticide
(e.g., weed and feed) products should be avoided.
Earth (2000) found the following:
1. Weed control and tolerance: Establish a realistic tolerance level for weeds and
use least toxic control methods to maintain it. For a low-input lawn, use least toxic
3-162 Chapter 3. Urban and Suburban
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
weed control methods such as cultivation, solarization, flaming, mowing, or herbicidal
soap. For a lower input lawn, grow strong healthy grass and it will crowd out weeds. For
the lowest input lawn, broaden your definition of lawn to include weeds that perform
desirable functions. [Note: Increasing the mowing height can shade the soil surface and
inhibit germination of weed seeds.]
2. Integrated pest management: Establish a realistic tolerance level for pests and
use least toxic control methods to maintain it. For a low-input lawn, use least toxic
control methods such as removing or trapping pests, introducing biological control
agents, or apply least toxic chemical controls such as insecticidal soaps. For a lower
input lawn, grow strong, healthy grass that can resist attack. For the lowest input lawn,
use cultural controls to prevent infestation, protect natural predators, and add beneficial
soil microbes.
As of January 1, 2010, products containing a combination of fertilizer and herbicide (commonly
known as weed and feed) are no longer available for sale or use in the Canadian province of
Alberta. That ban on the use of weed and feed fertilizers is because of potential health and
environmental impacts. Because weed and feed is applied to an entire lawn, regardless of the
size of the weed infestation, it results in an over-application of the herbicide 2, 4-D. Herbicide-
only products will still be available for spot application, because they result in less surplus
chemical draining from the lawn, running into storm sewers and entering waterways
(Environment Alberta 2010).
5.3.5 Mowing
Lawn mowing practices can affect the amount of fertilizer, pesticide, and irrigation inputs
needed. Mowing to a height of at least three inches shades out weeds, slows moisture loss,
protects grass vigor, and encourages deeper root growth. When grass is mowed too low, the
soil is exposed to light, which can stimulate weed seed germination (Earth 2000).
Mowing frequency is also an important factor. A general rule is to ensure that no more than one-
third of the grass leaf be cut at one time to prevent plant damage. Actual mowing frequency will
depend on the rate at which the grass is growing, which varies throughout the year (Earth
2000).
Recycling grass clippings by mulching them with a mulching mower and leaving them on the
lawn provides nutrients, helps to build soils, and preserves landfill space. Also, mulching leaves
into the grass adds organic matter and nutrients (Wilbe 2010). According to surveys, nearly
60 percent of Chesapeake Bay residents practice this form of grass recycling. Using a mulching
mower can help meet at least one-fourth of the nutrient needs of a yard and saves time required
Chapter 3. Urban and Suburban 3-163
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
to bag the clippings (Town of Culpeper 2009). A study by the University of Connecticut
Agricultural Station, as reported by Earth (2000), found that most of the N from recycled
clippings was incorporated into new grass growth within a week. The Rodale Institute Research
Center found that an acre of clippings provides an average of 235 pounds of N and 77 pounds
of P each year (Schultz 1989). Austin, Texas, having studied residential lawn fertilization
practices, recommends that by leaving clippings on the lawn, 60 percent of the clippings' N and
100 percent of the P will be available to the grass within the growing season (Garrett no date).
Grass clippings, leaves, fertilizer, and yard debris should be kept away from impervious areas,
because if left in the gutter or streets, they will be washed into storm sewers and surface waters
(Wilbe2010).
5.3.6 Soil Amendments
Background —Soil Compaction
Urban soils have been shown to be more compacted than undisturbed soils (Schueler2000c),
generally as a result of construction activities, heavy equipment use, and intentional
compaction. Foot and vehicular traffic can also compact soils. As measured by bulk density
(defined as the mass of dry soil divided by its volume, expressed in units of grams per cubic
centimeter (gms/cc)), undisturbed soils average 1.1 to 1.4 gms/cc, whereas urban lawns range
from 1.5 to 1.9 gms/cc and athletic fields and fill soil typically range from 1.8 to 2.0 gms/cc. The
bulk density of these disturbed soils can approach those of concrete (2.2 gms/cc).
An inverse relationship exists between soil bulk density and soil porosity, which indicates that
compacted urban soils do not infiltrate stormwater as readily as undisturbed soils. The
hydrologic consequence is higher runoff coefficients (Table 3-54), from 0.2 up to 0.5 (paved
areas have runoff coefficients ranging from 0.5 to 0.99).
Soil compaction also has implications for plant growth and can restrict root growth, oxygen
diffusion, nutrient retention, soil fauna, and inhibit beneficial fungi and other soil biota (Ocean
County Soil Conservation District 2001).
A study in North Central Florida revealed that construction activities reduced lawn infiltration
rates from 70 percent to 99 percent in comparison to untouched natural forest and pasture. "The
compacted pervious area effectively approaches the infiltration behavior of an impervious
surface," which increases stormwater runoff and the need for large stormwater conveyance
networks (Gregory et al. 2006).
3-164 Chapter 3. Urban and Suburban
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
Table 3-54. Runoff Coefficients (C) for Rational Formula
Land use
Business:
Downtown areas
Neighborhood areas
Residential:
Single-family areas
Multi units, detached
Munti units, attached
Suburban
Industrial:
Light areas
Heavy areas
Parks, cemeteries
Playgrounds
Railroad yard areas
C
0.70-0.95
0.50-0.70
0.30-0.50
0.40-0.60
0.60-0.75
0.25-0.40
0.50-0.80
0.60-0.90
0.10-0.25
0.20-0.35
0.20-0.40
Land Use
Lawns:
Sandy soil, flat, 2%
Sandy soil, avg., 2-7%
Sandy soil, steep, 7%
Heavy soil, flat, 2%
Heavy soil, avg., 2-7%
Heavy soil, steep, 7%
Agricultural land:
Bare packed soil
*Smooth
*Rough
Cultivated rows
*Heavy soil, no crop
*Heavy soil, with crop
*Sandy soil, no crop
*Sandy soil, with crop
Pasture
*Heavy soil
*Sandy soil
Woodlands
Asphaltic
Concrete
Brick
Unimproved areas
Drives and walks
Roofs
C
0.05-0.10
0.10-0.15
0.15-0.20
0.13-0.17
0.18-0.22
0.25-0.35
0.30-0.60
0.20-0.50
0.30-0.60
0.20-0.50
0.20-0.40
0.10-0.25
0.15-0.45
0.05-0.25
0.05-0.25
0.70-0.95
0.80-0.95
0.70-0.85
0.10-0.30
0.75-0.85
0.75-0.95
Source: http://water.me.vccs.edu/courses/CIV246/table2 print.htm
* The designer must use her or his judgment to select the appropriate C value within the range.
Generally, larger areas with permeable soils, flat slopes, and dense vegetation should have the lowest C
values. Smaller areas with dense soils, moderate to steep slopes, and sparse vegetation should have the
highest C values.
In examining 15 home lawns in central Pennsylvania, Hamilton and Waddington (1999) find
excavation procedures and lawn establishment to be the most influential practices affecting
lawn infiltration rates. Homes with minimal soil compaction had the highest infiltration rates.
Reduced compaction was achieved by bringing in topsoil post-home construction and through
core cultivation (aeration of the soil). The lawn with the highest infiltration rate (10cm/hr) was not
excavated during construction, allowing "the macropore system to stay intact, preventing
aggregate destruction during usual soil moving and handling, and preventing soil stratification
when the soil was put back at the excavated sites." Other practices that can affect infiltration
more than anything else are "the stripping of topsoil, traffic on exposed subsoil, the addition of
debris to the soil, and stratification of soil upon replacement."
Chapter 3. Urban and Suburban
3-165
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
Solutions to Reduce Soil Compaction
Soil amendments can be used to enhance soil properties and increase the infiltrative and
retentive capacity of soils. Soils can be amended by adding sand or other bulk materials,
organic matter such as compost, inorganic or organic fertilizers. Some evidence exists that
using compost teas and the inoculation of soils with soil microbes and mycorrhizal fungi can
increase soil health and plant productivity. However, most research to date has been conducted
on agricultural crops such as maize, wheat, and vegetables. The results of the studies
demonstrate that using biological approaches for nutrient management can enhance plant
nutrient use efficiency and improve soil water retention, aggregate stability, and the growth of
specific crops (Adesomoye et al. 2008; Shaharoona et al. 2008; Ahmad et al. 2008; Dass et al.
2008). Given those results, it is likely that similar benefits will accrue from using biological
approaches to turf management. Additional research, however, is needed to determine the
benefits that can be achieved by using biological approaches as they relate to the optimization
of turf grass performance, nutrient utilization, and soil health.
By mechanically treating, aerating, and amending disturbed soils, the physical structure of the
soil can be improved, bulk density can be reduced, and the porosity and infiltrative capacity of
the soils enhanced. In fine-textured (clay, clay loam) soils, the addition of compost/organic
materials reduces bulk density, improves friability (workability) and porosity, and increases its
gas and water permeability, thus reducing erosion. When used in sufficient quantities, adding
compost/organic materials provides both immediate and long-term positive effects on soil
structure so that fine-textured soils will resist compaction and increase their water-holding
capacity. Soil aggregation in coarse-textured (sandy) soils will be improved. Those issues are
discussed by Schueler (2000a) in an article that addresses reversal of soil compaction.
McDonald (2004) specifies 2 to 4 inches of compost tilled into the upper 8 to 12 inches of soil,
depending on soil type, before planting. Balousek (2003) showed a marked decrease in surface
runoff volume (36 to 53 percent) when compacted soils were chisel-plowed and deep-tilled, and
when soils were also amended with compost, runoff was reduced by 74 percent to 91 percent.
Additionally, compost is good source of N, P, and potassium and contains micronutrients
essential for plant growth. Therefore, adding compost can also have a positive effect on fertilizer
use and pH adjustment (lime/sulfur addition) and help reduce soil compaction. The benefits of
compost are described in more detail in the Composting Council fact sheet, Using Compost in
Stormwater Management, at www.compostingcouncil.org.
Redmond, Washington, has developed Guidelines for Landscaping with Compost Amended
Soils (City of Redmond Public Works 1998). The document also contains data on the
comparative costs of the use of soil amendments versus the use of other soil preparation
methods, and describes the benefits in terms of payback and increased infiltration rates and
reduced runoff. The city also quantified the reduced costs for detention facilities accrued from
3-166 Chapter 3. Urban and Suburban
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
using compost-amended soils because of the increase in moisture-holding capacity of the
amended soils. According to Hielema (1996), "the amended plots generated 53 percent to
74 percent of the runoff volume produced by unamended plots under saturated conditions."
Thus, under such conditions, stormwater detention facilities could be reduced in size because of
the holding capacity of the amended soils.
McCoy (2006) noted that soil amendments and soil treatments can be used to reduce
compaction and increase infiltration. For example, additions of sand and gravel in the design of
multiple layer soil profiles can reduce soil compaction and have the potential to decrease runoff
and retain water for subsequent evapotranspiration.
For more information, see the manual, Building Soil: Guidelines and Resources for
Implementing Soil Quality and Depth BMP T5.13 in Washington Department of Ecology's
Stormwater Management Manual for Western Washington 2010 Edition
(http://www.buildingsoil.org/tools/Soil BMP Manual.pdf).
5.3.7 Water Management
Landscape irrigation uses up to 1.5 billion gallons of water every day across the country (EPA
WaterSense). As reported by Mosko (2009), the Metropolitan Water District of Southern
California determined that up to 70 percent of residential water use in Southern California is for
outdoor irrigation, particularly lawns. Although the number of lawns in California is unknown,
84 percent of respondents in a 2000 statewide Air Resources Board survey described having a
lawn area, and the San Diego Union recently reported an estimate that residential lawns cover
300,000 acres and annually soak up 1.5 million acre-feet of water.
According to Mosko (2009), the most popular grasses in Southern California are fescues, which
generally require one inch of water per week during dry months and mowing about every other
week. Assuming modest-sized lawn areas of 25 feet by 25 feet in both front and in back yards,
the lawns could consume, in a single month, in excess of 3,000 gallons of water plus the
34 kilowatt hours of electricity required to deliver the water to Southern California homes.
Among other things, irrigation water waste is a product of inefficient system design, leaks,
improper nozzle use, broken nozzles, improper system pressure and improper watering
schedules. Excess water use can result in adverse environmental impacts, including over-
drafting groundwater resources, reduced stream flows, water quality degradation, and
disruptions to the ecosystems that depend on the water supplies (Vickers 2001).
Landscapes with automatic irrigation systems use more water than landscapes that water by
hand. In-ground sprinkler systems, automatic timers for irrigation, and drip irrigation systems
Chapter 3. Urban and Suburban 3-167
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
use 35 percent, 47 percent, and 16 percent more water than residences without these systems,
respectively (Mayer and DeOreo 1998). Although, hand-watering or using drought-tolerant
vegetation is most efficient, when irrigation systems are desired, reduced water consumption
can result from using efficient equipment; proper design, installation, and maintenance of
systems; and performing irrigation system audits regularly.
Efficient Irrigation Controllers
Weather-based irrigation controllers can produce water savings when replacing standard clock
timer controllers. Weather-based controllers schedule irrigation according to landscape needs
and local weather conditions. The technology eliminates the need for manual adjustments to the
irrigation schedule. In a Las Vegas, Nevada-based study, researchers found that
evapotranspiration-based controllers saved 20 percent more water than non-evapotranspiration-
based controllers (Devitt et al. 2008). In a study in Irvine, California, researchers found the use
of weather-based evapotranspiration controllers resulted in average water conservation savings
of 41 gallons/day. Highest water savings were seen in the summer and fall when irrigation
system use is highest. Researchers also found an average runoff reduction of 50 percent for
those sites that employed use of weather-based irrigation controllers (IRWD 2004).
EPA's WaterSense program has released a draft specification for weather-based irrigation
controllers and will label water-efficient controllers that meet its specification. Weather-based
irrigation controllers that earn the label must demonstrate that they meet the watering needs of
a typical landscape while not overwatering. For more information on the WaterSense label for
irrigation controllers, see http://www.epa.gov/watersense/products/controltech.html.
Efficient Irrigation Practices
To distribute water evenly to an irrigated landscape, an irrigation system must be designed and
installed with water efficiency in mind. Poorly designed irrigation systems result in water loss by
overwatering certain landscape areas causing runoff while under-watering other areas.
Landscape caretakers that use an irrigation system should ensure that the system is operating
efficiently by understanding the distribution uniformity (DU) of the irrigation system. DU is a
measure of the evenness of water applied to a landscape. An optimally performing irrigation
system will have a DU of 80 percent for rotary sprinklers and 75 percent for spray sprinklers
(The Irrigation Association 2007).
To test the DU of an irrigation system, a catch-can test is performed. A catch-can test involves
several steps: (1) note location of sprinkler heads; (2) place identically sized containers near
each sprinkler head and between heads; (3) run the sprinkler system until a minimum of 25 mm
3-168 Chapter 3. Urban and Suburban
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
of water is collected in a container; (4) record the volume of water collected from each
container; and (5) calculate the distribution uniformity:
DU = Average catch-can volume in lower 25% of catch-cans
Average catch-can volume overall
If the DU of a system is below 50 percent, consider hiring an irrigation professional to adjust the
system to obtain better performance and water savings. For more information on distribution
uniformity and the catch can test, see
http://www.ci.windsor.ca. us/DocumentView.aspx?DID=522.
EPA's WaterSense program partners with irrigation professionals trained in water-efficient
design, installation and maintenance, and auditing irrigation systems. An irrigation system
auditor will perform a catch can test on a property and provide customers with suggestions for
improving irrigation system efficiency. Although, as mentioned, watering by hand is the most
efficient means to irrigate a landscape, if an irrigation system is desired, use professionals
trained to reduce water consumption. For a list of WaterSense irrigation professionals, see
http://www.epa.gov/watersense/meet our partners.html.
Deficit irrigation, which is the practice of irrigating below the maximum water demand of the
turfgrass to decrease soil moisture content and water use can also be used to reduce water
consumption and irrigation. Shearman (2006) reported that water savings of 21 and 40 percent
were feasible in a test plot in Nebraska when Kentucky bluegrass received deficit irrigation of 60
and 80 percent of potential evapotranspiration while maintaining an acceptable turfgrass quality.
5.3.8 Grass Species Selection
Some grass species perform better than others under low-input management. In a 5-year field
trial in Rhode Island, hard fescue, tall fescue, colonial bentgrass, red fescue, and koeleria
(prairie junegrass) were able to maintain 100 percent turf cover on poor soil with no irrigation or
pesticides after establishment and only 1 to 2 pounds of N per 1,000 square feet per year
applied as organic, granular fertilizer. Kentucky bluegrass and perennial ryegrass were not able
to maintain cover under those conditions (Brown, R., personal communication 2010).
Another study in Rhode Island concluded that actively growing turfgrass used an average of
25 mm (1 inch) of water per week in July through September. Average rainfall for the same
12-week period is roughly 300 mm (12 inches). The water-holding ability of good soil and an
ability to go dormant if needed allows the grasses survive despite interannual variations in
rainfall patterns and timing. In fact, choosing grasses that can survive a dormancy period, and
Chapter 3. Urban and Suburban 3-169
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
allowing the plants to go dormant during prolonged dry periods is a key strategy for reducing
water use (Carrow et al. 2008).
According to Beard and Green (1994), "the proper strategy based on good science is the use of
appropriate low-water-use turfgrasses, trees, and shrubs for moderate-to-low irrigated
landscapes and similarly to select appropriate dehydration-avoidant and drought-resistant
turfgrasses, trees, and shrubs for nonirrigated landscape areas." It is also important when
choosing grasses for low-input management to use improved varieties. The improved varieties
have denser growth and better disease resistance than common types (Brown, R., personal
communication, 2010).
Devitt and Morris (2006) note the need to consider the effects of landscape species selection
including turf on water conservation and use, i.e., "Plant selection should be given serious
consideration in the development of low water-using landscapes." The authors also recommend
that,
[E]mphasis should be placed on the following factors:
1. Price water on the basis of its true societal value as a scarce resource.
2. Decrease irrigated landscape areas.
3. Track irrigations and adjust for changes in the seasonal demand of water. Irrigating
based on seasonal demand will almost always use less water than irrigating based on
guesswork.
4. Adjust landscape expectations down whenever possible and be more flexible in plant
selection (especially with those plants know to be high water users). Low growth rates
by decreasing fertilization and irrigations to achieve judicious size control.
If turfgrass is planted as ornamental vegetation in a landscape, choose native, drought-tolerant,
or low-water-use turfgrass species that require less water and maintenance. To identify species
appropriate for a site, consult lists of native species of vegetation. The Lady Bird Johnson
Wildflower Center provides native plant lists for the United States: http://www.wildflower.org/.
Local cooperative extension units can also provide information on planting regionally
appropriate species.
For functional turf areas, traditional turf species might be desired. Traditional turfgrass is
distinguished as warm-season or cool-season turfgrasses. Warm-season turfgrasses, such as
Bermuda grasses, zoysia grasses, buffalo grass, little bluestem, and Pennsylvania sedge, are
usually more drought tolerant and should be used in warmer climates. Some cool-season
turfgrasses, such as fine fescues, are drought tolerant but are more appropriate for cold-
3-170 Chapter 3. Urban and Suburban
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
weather climates. Other cool-season turfgrasses, such as Kentucky bluegrass, require high
amounts of water (35 inches per year just for survival) and are inappropriate for many areas in
the country (Vickers 2001).
One option when selecting grass species is to increase diversity by creating a mixed species
lawn that incorporates clovers or legumes into the turf mixture. A uniform distribution of such
plants can be achieved by evenly blending it with grass seed. Benefits include increased
drought tolerance, lower N needs, increased pest resistance, and decreased weed infestations
(Bellows 2010).
A combination of native grasses can provide a highly resistant, low-maintenance yard or turf.
For example, a combination of little bluestem (Schizachyrium scoparium), common or
Pennsylvania sedge (Carex pensylvanica), and tufted hairgrass (Deschampsia flexuosa) is well
adapted to the Northeastern coastal areas (Bellows 2010).
No-mow lawn mixes are composed of slow-growing turf grasses like hard fescue and creeping
red fescues, which require little maintenance because they have deep roots and are resistant to
drought. Sedges and rushes can also be used as a low-maintenance ground cover suitable for
moist climates (Bellows 2010).
Resources
The National Turfgrass Evaluation Program develops and coordinates uniform evaluation trials
of turfgrass varieties and promising selections in the United States and Canada. The results can
be used to determine the broad picture of the adaptation of a cultivar. Results can also be used
to determine if a cultivar is well adapted to a local area or level of turf maintenance.
http://www.ntep.org/contents2.shtml
The National Sustainable Agriculture Information Service (referred to as ATTRA) offers a
Sustainable Turf Care Guide for lawn care professionals, golf course superintendents, or
anyone with a lawn. The emphasis of the guide is on soil management and cultural practices
that enhance turf growth and reduce pests and diseases by reducing turf stress. It also includes
information about mixed species and wildflower lawns as low maintenance alternatives to pure
grass lawns, http://attra.ncat.org/attra-pub/turfcare.html
5.3.9 Turf Assessments
Municipalities and facility owners should have a qualified landscape professional (e.g., a
landscape architect, landscape designer, or other trained landscape professional) conduct an
assessment of turf areas to identify essential versus nonessential turf and opportunities to
Chapter 3. Urban and Suburban 3-171
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
reduce turf and decrease the inputs for turf areas that are retained as long as desired turf
performance can be achieved.
In some cases, active management of landscapes through irrigation, mowing prescription and
fertilization can enhance the environmental performance of the landscape. Easton and Petrovic
(2008) evaluated P loading from an urban watershed in New York, measuring dissolved P,
particulate P, and TP as well as site characteristic for three land uses: fertilized lawns, urban
barren areas, and wooded areas. They found that applying P in excess of plant requirements
can result in higher dissolved P in runoff, especially in areas that have been repeatedly over-
fertilized, i.e., on lawns. However, particulate (sediment-bound) P was highest in runoff from
land uses with the sparsest vegetation cover that have not been actively maintained (urban
barren areas and wooded areas). The researchers suggested that these areas could benefit
from judicious fertilization to improve groundcover and reduce erosion. Losses of dissolved P
from these areas during wet weather can be minimized by properly timing fertilizer applications
and matching the application rate to plant needs on the basis of soil tests.
Areas of essential turf should be determined by land owners/operators on the basis of factors
they identify. For example, essential turf areas can include turf for transit paths, security,
transportation visibility, historic preservation or dedicated recreational purposes such as picnic
areas and ball fields, buffers for public health reasons, and water pollution control practices
such as grassed swales. Nonessential turf areas are typically grassed areas that have not been
planted for a specific use or environmental purpose and receive little or no use or maintenance
except periodic mowing. Many of these grassed areas can be maintained only with turf cover
because of ease of maintenance, habit or for aesthetic continuity and can be converted to less
input-intensive ground covers that can provide increased habitat, improved aesthtics, and/or
environmental performance.
All turf areas should be assessed by category and managed accordingly to maximize
performance in terms of runoff reductions, erosion, nutrient discharges and infiltration. Areas
with thin grass cover, bare soil, or other indications that the turf is not performing optimally from
an environmental perspective should be identified and differentially managed by area or
category to achieve the desired filtration, water retention, pollutant removal and infiltration
objectives. In some cases, landscape managers might elect to convert turf to other landscape
cover types, let the turf revert to native forest, or increase management prescription to optimize
turf growth, thatch density, and nutrient and sediment retention
To reduce both the environmental effects of turf and management costs, communities and land
managers across the country are identifying areas that are mow zones, low-mow zones and
no-mow zones in an effort to reduce maintenance and provide increased ecological value from
landscaped areas. Converting turf areas back to naturalized areas is also a strategy to eliminate
3-172 Chapter 3. Urban and Suburban
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
the need to irrigate, fertilize, and apply pesticides except in cases where disease or invasive
species are problematic.
For areas that will remain as turf, further evaluation can identify areas that will be actively
managed (high-input) versus those that will be mowed and not treated with fertilizers and
pesticides. Facilities, campuses and other managers of large tracts of land should develop
landscape management plans, maps and operation and maintenance plans to properly manage
each designated category of vegetative cover including high-input and low-input turf areas.
Facility managers also might want to limit the creation or retention of high-input areas to the
most visible and used landscaped areas (e.g., areas adjacent to building entrances, transit
paths or areas where high quality turf is deemed essential). In contrast, lawns along the side
and back of buildings or at the edges of parking lots might not require such intensive
management and can be designated as low-input and low-mow areas. Examples of turf
conversion or reduction strategies are provided below.
• The U.S. National Arboretum in Washington, D.C., has undertaken measures to reduce
high-maintenance turf areas (U.S. Department of Agriculture, Agricultural Research
Service, no date). The Arboretum occupies 446 acres of green space, about half of
which is taken up by intensely managed gardens, collections, and research plots.
Arboretum managers have drastically reduced the area devoted to turf and have
changed the way the turf is managed. Large open spaces that were formerly devoted to
turf are now managed as meadows and account for about 70 acres, and areas that are
frequently mowed have been reduced to just 31 acres. Instead of mowing turf areas
weekly, as is standard practice, they mow in response to height thresholds, so that the
turf is mowed only 13 times on average during the growing season instead of 30 times
(less if drought slows turf growth). The mowing height threshold is 5 inches, which is
much higher than is commonly used on corporate campuses or on residential turf. They
do not generally irrigate or fertilizer turf, do not use pesticides or herbicides, and leave
clippings on the turf areas.
• Since 1995 the University of Nevada, Las Vegas has reduced turf on campus by
1,056,126 square feet, with an estimated water savings of more than 9 million gallons
and more than $20,000 annually. Its efforts include computer-controlled watering of
campus turf in compliance with water authority guidelines, enabling automatic shutdown
with the use of flow sensors, decoders, and automatic irrigation adjustment through an
evapotranspiration database, which is linked to the university's weather station for
automatic irrigation adjustment because of changes in weather. All landscaping around
new buildings is now xeriscaped, and more than 50,000 square feet of turf has been
replaced with desert landscaping at the Shadow Lane Campus. A landscape design is in
progress to reduce the heat-island effect of parking lots through tree planting in a project
Chapter 3. Urban and Suburban 3-173
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
being planned in partnership with the U.S. Division of Forestry. More information is at
http://barrickmuseum.unlv.edu/xeric/turf.html.
• Henderson, Nevada, Parks and Recreation Department has a turf reduction program
that involves removing nonfunctional turf from targeted areas in the parks system and
replacing it with more efficient xeriscaped areas. Since 2003 more than 85 turf
conversion projects have been completed, removing more than 1.2 million square feet of
turf, mostly from medians, parking lots, and areas where turf is primarily decorative. The
turf removal has translated into an annual savings of more than 68 million gallons of
water. The program was funded through a variety of grants and rebates rather than tax
dollars. More information is at http://www.citvofhenderson.com/parks/parks/turf-
conversion.php.
• A study was undertaken at the University of Waterloo in Ontario, Canada, to develop a
methodology for assessing all campus areas to identify candidates for turf conversion
(Hassan 2000). The study included an evaluation of stakeholder preferences, including
turf users (students and faculty) and university staff who maintain turf areas. A set of
criteria were established for evaluating existing turf areas according to current
conditions, visibility and aesthetics, and feasibility and suitability for alternate plantings.
More information is at
http://www.adm.uwaterloo.ca/infowast/watgreen/proiects/library/grass.pdf.
Another aspect that should be considered in turf management is irrigation. Areas planted in turf
should be assessed to determine necessary irrigation regimes and periodically evaluated to
identify opportunities to reduce water use on the basis of turf condition and other factors.
Carrow et al. (2008) provided an outline of the planning process and components of golf course
BMPs for water use efficiency/conservation that includes a framework for managing golf
courses and other landscapes to reduce water use. This assessment process, described below
in modified form, could be used to plan, assess and implement programs to promote water use
efficiency and conservation at most large, landscaped facilities or jurisdictions (adapted from
Carrow etal. 2008):
A. Initial planning and site assessment
1. Identification of water conservation measures and costs
2. Purpose and scope of the site assessment
3. Site assessment and information collection
a. Current water use profile
b. Irrigation/water system distribution audit
3-174 Chapter 3. Urban and Suburban
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
c. Site assessment information, e.g., alternative water sources, golf course design
modifications, and soil and climate conditions
B. Identify, evaluate and select water conservation strategies: and options and use the
following 10 Core Water Conservation Strategies:
1. Use nonpotable water sources for irrigation—alternative water sources; water
harvesting/reuse
2. Efficient irrigation system design and monitoring devices for implementing water
conservation, e.g., remote sensing and real-time control devices
3. Efficient irrigation system scheduling/operation
4. Developing and selecting turfgrasses and other landscape plants with respect to
water uptake and use requirements in terms of quantity and quality
5. Landscape design for water conservation
6. Altering practices to enhance water-use efficiency, e.g., soil amendments, cultivation,
mowing, fertilization
7. Indoor water conservation measures in buildings, air conditioning units, pools, and
other facilities associated with a landscape site
8. Educating management and staff in water conservation management practices and
approaches
9. Developing formal conservation and contingency plans
10. Monitor and revise plans
C. Assess benefits and costs of water conservation measures on stakeholders
1. Benefits—direct and indirect
2. Costs
a. Facility costs for past and planned implementation of water conservation
strategies and practices
b. Labor needs/costs
c. Costs associated with changes in management practice, e.g., water and soil
treatments, posting of signs, training
Resource
Hassan, S. 2000. Campus Landscape Study: The Conversion of Turf Areas to Alternate Forms
of Ground Cover.
. Accessed
February 17, 2010.
Chapter 3. Urban and Suburban 3-175
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
5.3.10 Turf Restrictions
Limiting the amount of landscaped area for turfgrass and high water use plantings can reduce
landscape irrigation demand. A number of municipalities limit turf areas. For example, the Marin
Municipal Water District in California limits use of turfgrass and high water use plants to
35 percent of the total landscaped area (Marin Municipal Water District Ordinance 326, In
Vickers 2001). Clark County, Nevada, set limits on turf areas for new properties according to
drought conditions. Under non-drought conditions, the following limits apply:
• Single-family homes: 50 percent of a front yard can be grass, not including driveway or
parking areas
• Multifamily (apartments, condos) and nonresidential developments: 30 percent of an
area set aside for landscaping can be grass, excluding parking lots and driveways
• Golf courses: Limited to a maximum of 90 acres for 18 holes and 10 acres for driving
ranges
For nonresidential landscapes, installing new turf is prohibited during drought conditions, with
some exceptions for public spaces that have functional turf. For single-family and multifamily
developments, installing new turf is prohibited in common areas of residential neighborhoods
during a Drought Watch, and during a more severe Drought Alert, new turf is prohibited in
residential front yards and cannot exceed 50 percent of the gross area of the side or rear yard
or 100 square feet, whichever is greater. A maximum of 5,000 square feet of turf is permitted.
The details of the Clark County Drought Restrictions are at
http://librarv.municode.com/HTML/16214/level2/T30pt2 30.64.html.
5.3.11 Incentives for Landscape Conversion
Some communities use incentives to urge property owners to convert their lawns to less
maintenance-intensive landscaping. Federal facilities planners will find such types of municipal
incentive programs to be of interest because they provide documentation of the benefits
achieved from lawn conversion. The following are examples of lawn conversion incentive
programs:
• Gary, North Carolina, initiated a one-time, $500 per property payment to homeowners
who convert at least 1,000 square feet of historically irrigated turf to natural area or
warm-season grass. Homeowners must demonstrate past irrigation, submit a description
of their conversion project, and provide receipts documenting the project. Customers are
allowed a waiver of alternate-day watering restrictions to encourage establishment of
new plantings, and thereafter are required to reduce their water budgets by 25 percent.
A post-conversion site review is conducted to confirm successful establishment of the
replacement landscape. During spring and summer months, the town anticipates a
3-176 Chapter 3. Urban and Suburban
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
savings of about 675 gallons per month for each 1,000 square feet converted to natural
landscape, and approximately 567 gallons saved per month for each 1,000 square feet
of warm season grass conversion (Town of Gary 2009).
http://www.townofcarv.orq/Departments/Public Works and Utilities/Conservation/Water
Conservation/Incentive Programs/Turf Buy Back Program/Turf Buy Back Program
Fact Sheet.htm
The Southern Nevada Water Authority's (SNWA's) Water Smart Landscapes rebate
helps property owners convert water-thirsty grass to xeriscape. SNWA will rebate
customers $1.50 per square foot of grass removed and replaced with desert landscaping
up to the first 5,000 square feet converted per property, per year. Beyond the first
5,000 feet, SNWA will provide a rebate of $1 per square foot. The maximum award for
any property in a fiscal year is $300,000. http://www.snwa.com/html/cons wsl.html
Resources
EPA's WaterSense program has a specification for water-efficient, single-family new homes that
includes landscape criteria. The specification requires use of a water budget tool to help
calculate a regionally appropriate allotment of turfgrass for a residence or a turfgrass reduction
to 40 percent of the landscaped area. Although the tool is designed for use by builders
designing new homes, consumers can use it in existing landscapes to help understand whether
their use of turfgrass and other high water using plants is appropriate for their region. To learn
more about the water budget tool, see
http://www.epa.gov/watersense/nhspecs/homes final.html
The SSI provides guidance on sustainable landscaping. One of the criteria for which it has
developed guidance is site design for water conservation. To participate in the program,
landscapes are required to reduce potable water use for irrigation by 50 percent from a
baseline. Reductions can be accomplished through using regionally appropriate plantings,
irrigation efficiency (drip irrigation), using captured rainwater, and using recycled graywaterto
name a few. To track landscape water savings, SSI uses a water budget tool adapted from
EPA's WaterSense program that has additional criteria, requiring a greater reduction in outdoor
water use. For more information, see http://www.sustainablesites.org/.
Chesapeake Bay Foundation. 2007. Healthy Lawns, Healthy Waters: A Guide to Effective Lawn
Care for the Chesapeake Bay Watershed. http://www.cbf.org/Document. Doc?id=59.
Accessed February 9, 2010.
U.S. Fish and Wildlife Service. 2003. Native Plants for Wildlife Habitat and Conservation
Landscaping: Chesapeake Bay Watershed.
http://www.nps.gov/plants/pubs/Chesapeake/toc.htm. Accessed February 9, 2010.
Chapter 3. Urban and Suburban 3-177
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
5.3.12 Environmentally Friendly Landscape Requirements
Plant selection and planning have a significant effect on the amount of maintenance and inputs
needed to maintain attractive landscaping. Landscaping that is considered environmentally
friendly requires few inputs and focuses on the use of native landscaping, the use of drought-
tolerant or locally adapted plants, and other features such as rainwater harvesting, infiltration
areas, and street trees. Several regional programs promote such landscaping principles,
including the BayScapes program for the Chesapeake Bay region and Bay-Friendly
Landscaping in the San Francisco Bay area. The following are examples of communities that
have adopted environmentally friendly landscaping requirements for certain types of
development projects:
• The Oro Loma Sanitary District in the San Francisco Bay area of California has adopted
an ordinance requiring the integration of green building and Bay-Friendly landscaping
strategies in district and public-private partnerships buildings and landscapes. Projects
are required to meet the most recent minimum Bay-Friendly Landscape Guidelines and
Bay-Friendly Landscape Scorecard points (http://www.stopwaste.org/docs/bay-
friendly landscape guidelines - all chapters.pdf).
www.oroloma.org/asset/regulation/ordinance%2043.pdf
• Miami-Dade County, Florida, has established landscaping requirements for right-of-way
landscapes that promote xeriscape and Florida-Friendly principles by setting minimum
standards for irrigation and selection of plant material and mulch. The ordinance requires
the use of drought-tolerant species and grouping of plants by water requirements, and it
sets limits on irrigation systems. It also aims to promote trees for a variety of
environmental benefits and to reduce exotic pest plants.
http://www.miamidade.gov/govaction/matter.asp?matter=091097&file=true&yearFolder=
Y2009
Resources
StopWaste.org. 2008. Bay-Friendly Landscape Guidelines: Sustainable Practices for the
Landscape Professional, http://www.stopwaste.org/docs/bay-
friendly landscape guidelines - all chapters.pdf. Accessed February 9, 2010.
U.S. Fish and Wildlife Service, Chesapeake Bay Field Office. 2009. BayScapes.
http://www.fws.gov/ChesapeakeBay/bayscapes.htm. Updated November 3, 2009.
Accessed February 9, 2010.
3-178 Chapter 3. Urban and Suburban
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
5.3.13 Xeriscaping Requirements
Xeriscaping is a type of landscaping that conserves water through planting of native, water-
efficient plants rather than water-intensive ones and using techniques that minimize the need for
irrigation. Xeriscaping has water quality benefits in addition to water conservation benefits
because it helps to prevent dry-weather runoff from over-irrigation.
Although xeriscaping is a common practice in arid areas, the concept can be applied in the
Chesapeake Bay watershed. The National Institutes of Health in Bethesda, Maryland, has
created ground level xeriscaped areas using green roof soil media and plants near their security
entrance to reduce runoff and provide a low maintenance aesthetically pleasing landscape
(Figure 3-29).
Figure 3-29. Xeriscape landscaping at NIH Campus (from Waring 2007).
Xeriscaping programs, typically, are voluntary and focus on education and outreach, although
some communities have implemented xeriscaping requirements as part of their landscaping
codes, and others have developed incentive programs. The following are examples of both
regulatory and incentive approaches to xeriscaping.
• Rancho Cucamonga, California, has a xeriscape requirement for developments requiring
landscaping plans (with some exemptions, including single-family homes and public
spaces). Developments with model homes are required to use xeriscaping on half of the
models, including low water use plants, water-saving irrigation systems, and signage
Chapter 3. Urban and Suburban
3-179
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
indicating to buyers the water-saving landscape design features.
http://search.municode.com/html/16570/level2/T19 C19.16.html
Mesa, Arizona, offers a Grass-to-Xeriscape rebate to encourage single-family
homeowners to replace their lawns with xeriscapes. When a customer removes
500 square feet or more of established grass and replaces it with a xeriscape, the Mesa
provides a $500 rebate, http://www.mesaaz.gov/conservation/grass-to-xeriscape-
rebate.aspx
Gallup, New Mexico, has a Xeriscape Rebate Application Program in which customers
are eligible to receive a rebate on their water bill for each square foot of irrigated turf
grass, removed and replaced with an approved xeriscape landscape (the city provides a
Xeriscape Plant List). Twenty-five percent of the qualifying total square footage of
irrigated turf grass removed must be replaced with qualifying xeriscape plants, subject to
inspection and approval. http://www.ci.gallup.nm.us/GJU/Gallup-
Xeriscape%20Rebate%20Application.pdf
In 2006 California passed the Water Conservation in Landscaping Act to require local
municipalities to adopt landscape water conservation ordinances by 2010. To assist
municipalities with compliance, the state issued a Model Water Efficient Landscape
Ordinance and accompanying technical resources, including a compendium of existing
local ordinances addressing water-efficient landscaping. The model ordinance and
technical assistance information are at
http://www.water.ca.gov/wateruseefficiency/landscapeordinance/.
3-180 Chapter 3. Urban and Suburban
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
6 References
Allmendinger, N.E., J.E. Pizzuto, G.E. Moglen, and M. Lewicki. 2007. A sediment budget for a
sediment budget for an urbanizing watershed, 1951-1996, Montgomery County, Maryland,
U.S.A. Paper No. J05051 of the Journal of the American Water Resources Association.
Received April 25, 2005; accepted March 29, 2007.
American Forests. 201 Oa. CITYgreen. American Forests, Washington, DC.
. Accessed February 23,
2010.
American Forests. 2010b. Trees Reduce Stormwater. American Forests, Washington, DC.
. Accessed February 23, 2010.
Arendt, R. 1999. Growing Greener: Putting Conservation into Local Plans and Ordinances.
National Lands Trust-American Planning Association-American Society of Landscape
Architects, Island Press, Washington, DC.
Aronson, L.J., A.J. Gold, R.J. Hull, and J.L. Cisar. 1987. Evapotranspiration of cool-season
turfgrasses in the humid Northeast. Agron. J. 79:901-905.
ASFPM (Association of State Floodplain Managers). 2010. Natural and Beneficial Floodplain
Functions: Floodplain Management—More than Flood Loss Reduction. Association of
State Floodplain Managers, Madison, Wl. . Accessed February 23,
2010.
ASLA (American Society of Landscape Architects). 2009. Guidelines and performance
benchmarks. Sustainable Sites Initiative Project. American Society of Landscape
Architects, Washington, DC.
Balousek, J.D. 2003. Quantifying Decreases in Stormwater Runoff from Deep Tilling, Chisel
Plowing, and Compost-Amendment. Dane County Land Conservation Department, Dane
County, IL.
. Accessed February 9, 2010.
Barrett, M.E., P.M. Walsh, J.F. Malina, and R.J. Charbeneau. 1998. Performance of Vegetative
Controls for Treating Highway Runoff. Journal of Environmental Engineering 124:11.
Earth, C.A. 2000. Toward a low-input lawn. Article 130 in The Practice of Watershed Protection.
Ed. byT. Schuelerand H. Holland. Center for Watershed Protection, Ellicott City, MD.
Chapter 3. Urban and Suburban 3-181
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
Beard, J.B., and R.L. Green. 1994. The role of turfgrasses in environmental protection and their
benefits to humans. Journal of Environmental Quality 23(3):452-460.
Beck, R., L. Kolankiewicz, and S.A. Camarota. August 2003. Outsmarting Smart Growth:
Population Growth, Immigration, and the Problem of Sprawl. Center for Immigration
Studies, Washington, D.C.
. Accessed
March 10,2010.
Beezhold, M.T., and D.W. Baker. 2006. Rain to Recreation: Making the Case for a Stormwater
Capital Recovery Fee. In Proceedings of the Water Environment Federation (WEFTEC),
2006.
Bell, G., and J. Moss. 2006. Mowing Practices Reduce Runoff From Turf.
. Accessed February, 25,
2010.
Bellows, B. 2010. Sustainable Turf Care, Horticulture Systems Guide.
. Accessed March 8, 2010.
Bharati, L., K.H. Lee, T.M. Isenhart, and R.C. Schultz. 2002. Soil-water infiltration under crops,
pasture, and established riparian buffer in Midwestern USA. Agroforestry Systems
56:249-257 . Accessed May
6, 2010.
Boughton, W.C. 2005. Effect of data length on rainfall-runoff modeling. Environmental Modelling
& Software 22(3):406-413. (Special section: Advanced Technology for Environmental
Modelling).
Brookings Institute. 2004. Toward a new metropolis: the opportunity to rebuild America. Arthur
Nelson. Virginia Polytechnic Institute and State University. Discussion Paper. Brookings
Institution Metropolitan Policy Project, Washington, DC.
CAC (Critical Area Commission). 2003. Guidance for complying with the 10% stormwater rule in
the IDA of the Maryland Critical Area Zone. Maryland Department of Natural Resources,
Annapolis, MD
California DWR (Department of Water Resources). 2010. Water Efficient Landscape Ordinance.
California Department of Water Resources, Sacramento, CA.
. Accessed February
24,2010.
Campbell DeLong Resources, Inc. 2008. Citizen Response to Sustainable Stormwater
Management in Inner Southeast Portland. Focus Group Research Conducted for City of
Portland Environmental Services, Portland, OR.
3-182 Chapter 3. Urban and Suburban
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
Cappiella, K., T. Schueler, and T. Wright. 2005. Urban Watershed Forestry Manual. Part 1:
Methods for Increasing Forest Cover in a Watershed. U.S. Department of Agriculture
Forest Service, Newtown Square, PA
Cappiella, K., T. Schueler, and T. Wright. 2006. Urban Watershed Forestry Manual. Part 2:
Conserving and planting trees at development sites. U.S. Department of Agriculture,
Forest Service, Newtown Square, PA.
Carrow, R.N., R.R. Duncan, and M.T. Huck. 2008. Turfgrass and Landscape Irrigation Water
Quality: Assessment and Management. CRC Press, Boca Raton, FL.
Casey Trees. 2008. Green Build-out Model. Casey Trees, Washington, DC.
. Accessed
February 23, 2010.
CASQA (California Stormwater Quality Association). 2004. California Stormwater Best
Management Practice Handbooks. California Stormwater Quality Association, Menlo Park,
CA. . Accessed February 24, 2010.
Chang, M. 1977. An evaluation of precipitation of gage density in mountainous terrain. Journal
of the American Water Resources Association 13(1):39-46 (published online June
8, 2007).
Cheng, M.S., C.A. Akinbobola, J. Zhen, J. Riverson, K. Alvi, and L Shoemaker. 2009. BMP
decision support system for evaluating Stormwater management alternatives. Frontieers of
Environmental Science & Engineering in China 3(4):453-463.
. Accessed February
23,2010.
Chesapeake Bay Foundation. 2007. Healthy Lawns, Healthy Waters: A Guide to Effective Lawn
Care for the Chesapeake Bay Watershed. Chesapeake Bay Foundation, Annapolis, MD.
. Accessed February 9, 2010.
Chesapeake Bay Foundation. No date. Facts About Nutrient Trading from the Chesapeake Bay
Foundation. Chesapeake Bay Foundation, Annapolis, MD.
. Accessed February 23, 2010.
Chesapeake Bay Program. 2009. Developing Best Management Practice Definitions and
Effectiveness Estimates for Nitrogen, Phosphorus, and Sediment in the Chesapeake Bay,
December 2009. Chesapeake Bay Program, Annapolis, MD.
. Accessed
February 23, 2010.
Chapter 3. Urban and Suburban 3-183
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
Chesapeake Stormwater Network. 2009. The Clipping Point: The Grass Crop of the
Chesapeake Bay Watershed. Baltimore, MD. .
Updated June 10, 2009. Accessed February 4, 2010.
Chesapeake Stormwater Network. 2010. Technical Bulletin No. 8, The Clipping Point: Turf
Cover Estimates for the Chesapeake Bay Watershed and Management Implications.
Chesapeake Stormwater Network, Baltimore, MD.
City of Annapolis. 2008. Ordinance No. O-10-08 Amended. City Council of the City of Annapolis,
MD. .
Accessed February 24, 2010.
City of Baltimore. 2006. 2005 NPDES MS4 Stormwater Permit Annual Report. Prepared for
Maryland Department of Environment, Water Management Administration, Baltimore, MD,
by Baltimore Department of Public Works, Baltimore, MD.
City of Bellingham. 1995. Water and Sewers. Bellingham, WA.
. Accessed February 24, 2010.
City of Emeryville. 2005. Stormwater Guidelines for Green Dense Redevelopment. Stormwater
quality solutions for the City of Emeryville, CA. Community Design and Architecture,
Emeryville, CA.
City of Gallup. 2008. Xeriscape Rebate Application Program. Gallup Joint Utilities, Gallup, NM.
.
Accessed February 24, 2010.
City of Henderson. 2010. Turf Conversion. Henderson, NV.
. Accessed February
24,2010.
City of Highland Park. 2010. Regarding the Use of Fertilizers Containing Phosphorus. Highland
Park, IL. .
Accessed February 24, 2010.
City of Mesa, Arizona. 2009. Grass-to-Xeriscape Landscape Rebate.
. Accessed
February 24, 2010.
3-184 Chapter 3. Urban and Suburban
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
City of New York. 2008. Plan NYC, Appendix C. City of New York, New York, NY.
. Accessed
February 24, 2010.
City of Philadelphia. 2008. Stormwater Management Guidance Manual. Version 2.0.
Philadelphia Water Department, Office of Watersheds, Philadelphia, PA
City of Philadelphia. 2009. Long Term Control Plan Update, Supplemental Documentation,
Volume 3, Basis of Cost Opinions. City of Philadelphia, Philadelphia, PA.
. Accessed February 24, 2010.
City of Philadelphia. 2010. Philadelphia Going Green. City of Philadelphia, Philadelphia, PA.
. Accessed February 23, 2010.
City of Philadelphia. No date. Philadelphia's Stormwater Manual. Philadelphia Water
Department, Philadelphia, PA.
. Accessed February 24,
2010.
City of Portland. 2004. City of Portland Stormwater Manual. City of Portland, Environmental
Services, Clean River Works, Portland, OR.
. Accessed February 22, 2010.
City of Portland. 2008a. Cost Benefit Evaluation ofEcoroofs 2008. City of Portland Bureau of
Environmental Services, Portland, OR.
. Accessed
February 23, 2010.
City of Portland. 2008b. Portland Stormwater Management Manual. Bureau of Environmental
Services, Portland, OR.
City of Redmond, Washington. 1998. Guidelines for Landscaping with Compost-Amended Soils.
. Accessed February 25, 2010
City of Seattle. 201 Oa. Green Stormwater Infrastructure. Seattle Public Utilities, Seattle, WA.
. Accessed February 23, 2010.
City of Seattle. 201 Ob. Natural Drainage Projects. Seattle Public Utilities, Seattle, WA.
. Accessed February 23, 2010.
Chapter 3. Urban and Suburban 3-185
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
City of Seattle. 201 Oc. Street Edge Alternatives. Seattle Public Utilities, Seattle, WA.
. Accessed
February 23, 2010.
Clark County, Nevada. 2007. 30.64 - Site Landscape and Screening Standards.
. Accessed March
10,2010.
Clark, S.E., R. Pitt, and R. Field. 2009. Groundwater Contamination Potential from Infiltration of
Urban Stormwater Runoff. Chapter 6 in The Effects of Urbanization on Groundwater: An
Engineering Case Based Approach for Sustainable Development. Committee on
Groundwater Hydrology, ASCE/EWRI.
CNT (Center for Neighborhood Technology). No date. Green Values Stormwater Toolbox.
Center for Neighborhood Technology, Chicago, IL.
. Accessed February 23, 2010.
Cohen, A. 2006 Narrow Streets Database. Congress for the New Urbanism.
. Accessed March 5, 2009.
CRWD (Capitol Region Watershed District). 2010. CRWD Stormwater BMP Performance
Assessment and Cost-Benefit Analysis, . Accessed
March 10,2010.
CSN (Chesapeake Stormwater Network). 2009. Baywide Design Specifications. Chesapeake
Stormwater Network, Baltimore, MD. . Accessed February 24, 2010.
CSN (Chesapeake Stormwater Network). 2010. Entries in Baywide Design Specifications (15).
Chesapeake Stormwater Network, Baltimore, MD.
. Accessed February 24, 2010.
Culpeper, Virginia. 2009. The busy person's guide to lawn care. Culpeper Minutes 36:33.
. Accessed March 10, 2010.
CWP (Center for Watershed Protection). 1998. Better Site Design: A Handbook for Changing
Development Rules in Your Community. Center for Watershed Protection, Ellicott, MD.
. Accessed February 23, 2010.
3-186 Chapter 3. Urban and Suburban
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
CWP (Center for Watershed Protection). 2001. Stormwater Practices for Cold Climates. Center
for Watershed Protection, Ellicott City, MD.
. Accessed
February 24, 2010.
CWP (Center for Watershed Protection). 2003-2008. Urban Subwatershed Restoration Manual
Series. Center for Watershed Protection, Ellicott City, MD.
. Accessed February 23, 2010.
CWP (Center for Watershed Protection). 2004. Pollution source control practices. Manual 8 in
the Urban Subwatershed Restoration Manual Series. Center for Watershed Protection,
Ellicott City, MD.
CWP (Center for Watershed Protection). 2007. National Pollutant Removal Performance
Database, Versions. Center for Watershed Protection, Ellicott City, MD.
.
Accessed February 24, 2010.
CWP (Center for Watershed Protection). 2008a. Better Site Design Resources. Center for
Watershed Protection, Ellicott City, MD.
. Accessed
February 23, 2010.
CWP (Center for Watershed Protection). 2008b. Managing Stormwater in Your Community: A
Guide for Building an Effective Post-Construction Program. Center for Watershed
Protection, Ellicott City, MD.
. Accessed February 23, 2010.
Dane County, Wsconsin. No date. Phosphorus Control in Dane County.
. Accessed March 10, 2010.
DDOT (District Department of Transportation). 2005. Anacostia Waterfront Transportation
Architecture Design Standards. District Department of Transportation, Washington, DC.
. Accessed February 23, 2010.
Delaware DNREC (Department of Natural Resources and Environmental Control). 1997.
Conservation Design for Stormwater Management: A Design Approach To Reduce
Stormwater Impacts from Land Development and Achieve Multiple Objectives Related to
Land Use. Delaware Department of Natural Resources and Environmental Control and
The Environmental Management Center of the Brandywine Conservancy, Dover, DE.
. Accessed February 23, 2010.
Chapter 3. Urban and Suburban 3-187
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
Devereux, O.H., K.L. Prestegaard, B.A. Needelman, and A.C. Gellis. 2010. Suspended-
sediment sources in an urban watershed, Northeast Branch Anacostia River, Maryland.
Hydrological Processes, Accepted 2009.
Devitt, D.A., K. Carstensen, and R.L. Morris. 2008. Residential water savings associated with
satellite-based ET irrigation controllers. Journal of Irrigation and Drainage Engineering
134(1):74-82
Dierke, S. 2007. Not all green space is created equal: The hydrologic benefits of native
landscapes. Stormwater, the Journal for Surface Water Quality Professionals March-April
(2007). .
Accessed May 5, 2010
Easton, Z.M., and A.M. Petrovic. 2004. Fertilizer source effect on ground and surface water
quality in drainage from turfgrass. Journal of Environmental Quality 33:645-655
Easton, Z.M., and A.M. Petrovic. 2008. Determining Phosphorus Loading Rates Based on Land
Use in an Urban Watershed. Chapter 3 in The Fate of Nutrients and Pesticides in the
Urban Environment, ed. M.T. Nett, M.J. Carroll, B.P. Morgan, and A.M. Petrovic, pp. 43-
62. American Chemical Society, Washington, DC.
ECONorthwest. 2007. The Economics of Low-Impact Development: A Literature Review.
EcoNorthwest, Eugene, OR.
Eisenburg, B. 2008. Design, Engineering, Installation, and O&M Considerations for
Incorporating Stormwater Low Impact Development (LID) in Urban, Suburban, Rural, and
Brownfields Sites. American Society of Civil Engineers (ASCE), Low Impact Development
Conference Proceedings, 2008.
Environment Alberta. Alberta Bans Fertilizer-Herbicide Combination Products.
. Accessed March 11, 2010.
Fender, D. 2008. Urban turfgrass in times of a water crisis: Benefits and concerns. In Water
Quality and Quantity Issues for Turfgrasses in Urban Landscapes, eds, J.B. Beard and
M.P. Kenna. Council for Agricultural Science and Technology, Ames, IA.
Fishel, F.M. 2007. Pesticide Use Trends in the U.S.: Pesticides for Home. University of Florida,
I FAS Extension. Gainesville, FL. . Updated
January 2007. Accessed February 9, 2010.
FISRWG (Federal Interagency Stream Restoration Working Group). 1998. Stream Corridor
Restoration: Principles, Processes, and Practices. National Technical Information Service,
Alexandria, VA.
3-188 Chapter 3. Urban and Suburban
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
Foster, R.S. 1994. Landscaping that Saves Energy and Dollars. Globe Pequot Press, Old
Saybrook, CT.
Garrett, H. No date. Fertilizer Recommendations Dramatic Changes for Austin.
http://www.dirtdoctor.com/organic/garden/view org research/id/101. Accessed April 30,
2010.
Gellis, A.C., C.R. Hupp, J.M. Landwehr, and M.J. Pavich. 2007. Synthesis of U.S. Geological
Survey Science for the Chesapeake Bay Ecosystem and Implications for Environmental
Management, Chapters: Sources and Transport of Sediment in the Watershed. U.S.
Geological Survey Circular 1316. U.S. Geological Survey, Reston, VA.
Gellis, A.C., C.R. Hupp, M.J. Pavich, J.M. Landwehr, W.S.L. Banks, B.E. Hubbard, M.J.
Langland, J.C. Ritchie, and J.M. Reuter. 2009. Sources, transport, and storage of
sediment in the Chesapeake Bay Watershed. U.S. Geological Survey Scientific
Investigations Report 2008-5186. U.S. Geological Survey, Reston, VA.
Geosyntec Consultants and Wright Water Engineers. 2008. Analysis of Treatment System
Performance: International Stormwater Best Management Practices (BMP) Database
(1999-2008). Prepared for Water Environment Research Foundation, American Society of
Civil Engineers (Environmental and Water Resources Institute/Urban Water Resources
Research Council), U.S. Environmental Protection Agency, Federal Highway
Administration, and American Public Works Association, by Geosyntec, Atlanta, GA.
Geosyntec Consultants and Wright Water Engineers. 2009. Urban Stormwater BMP
Performance Monitoring. International Stormwater BMP Database.
. Accessed February 23, 2010.
Gregory, J.H., M.D. Dukes, P.H. Jones, and, G.L. Miller. 2006. Effect of urban soil compaction
on infiltration rates. Journal of Soil and Water Conservation 61 (3): 117-125
Griffiths-Sattenspiel, B., and W. Wilson. 2009. The Carbon Footprint of Water. The River
Network. .
Hamilton, G.W., and D.V. Waddington. 1999. Infiltration rates on residential lawns in central
Pennsylvania. Journal of Soil and Water Conservation 54(3):564-568.
Hassan, S. 2000. Campus Landscape Study: The Conversion of Turf Areas to Alternate Forms
of Ground Cover. University of Waterloo, Waterloo, Ontario, Canada.
. Accessed
February 17, 2010.
Hendrix, S. 2010. D.C. shoppers opt for roughing it over paying 5-cent bag tax. Washington
Post. Saturday, January 23, 2010.
Chapter 3. Urban and Suburban 3-189
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
Hielema, E. 2006. Hydrologic Simulation of the Klahanie Catchment, King County, Washington,
With and Wthout a Landscape Consisting of Soil Amended with Compost, Master Thesis.
University of Washington, College of Engineering, Seattle, WA.
Hinman, C. 2005. Low Impact Development Manual—Technical Guidance Manual forPuget
Sound. Puget Sound Action Team, Washington State University Pierce County Extension,
Tacoma, WA. . Accessed
February 22, 2010.
Hunt, B., J. Wright, and D. Jones. No date. Evaluating LID for an Engineering Development in
the Lockwood Folly Watershed, North Carolina. North Carolina State University, Raleigh,
NC. .
Accessed February 24, 2010.
Irrigation Association. 2007. Landscape Irrigation Auditor, . Accessed
March 10,2010.
IRWD (Irvine Ranch Water District). 2004. The residential runoff reduction study.
. Accessed March 4,
2010.
ITRC (Interstate Technology & Regulatory Council). 2009. Phytotechnology Technical and
Regulatory Guidance. The Interstate Technology & Regulatory Council, Washington, DC.
. Accessed February 24, 2010.
i-Tree. 2010. What Is /-Tree? USDA Forest Service, Washington,
DC.. Accessed February 23, 2010.
Jefferson Township. 2006. Application of Phosphorus Fertilizer Prohibited. Morris County, NJ.
. Accessed February 24, 2010.
Karst Working Group. 2009. Technical Bulletin No. 1 Stormwater Design Guidelines for Karst
Terrain in the Chesapeake Bay Watershed Version 2.0. Chesapeake Stormwater Network,
Ellicott City, MD.
Kaushal, S.S, G.E. Likens, N.A. Jaworski, M.L Pace, A.M. Sides, D. Seekell, K.T. Belt, D.H.
Secor, and R.L. Wingate. 2010. Rising Stream and River Temperatures in the United
States. Frontiers in Ecology and the Environment, Washington, DC.
Kaushal, S.S., P.M. Groffman, P.M. Mayer, E. Striz, and A.J. Gold. 2008. Effects of stream
restoration on denitrification in an urbanizing watershed. Ecological Applications
18(3): 789-804.
3-190 Chapter 3. Urban and Suburban
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
Kays, B.L. 1980. Relationship of forest destruction and soil disturbance to increased flooding in
suburban North Carolina piedmont. In METRIA—Proceedings of the Third Conference of
the Metropolitan Tree Improvement Alliance, Rutgers State University, NJ; 118-125. As
cited in Center for Watershed Protection. 2005. Urban Watershed Forestry Manual Part 1:
Methods for Increasing Forest Cover in a Watershed
Klocker, C.A., S.S. Kaushal, P.M. Groffman, P.M. Mayer, and R.P. Morgan. 2009. Nitrogen
uptake and denitrification in restored and unrestored streams in urban Maryland, USA.
Aquatic Sciences 71 (4):411-424.
Kopits, E., V. McConnell, and M. Walls. 2007. The trade-off between private lots and public
open space in subdivisions at the urban-rural fringe. American Journal of Agricultural
Economics 89(5):1191-1197.
Kussow, W.R. 2008. Nitrogen and Soluble Phoshorus Losses from an Upper Midwest Lawn. P
1-18. In The Fate ofturfgrass Nutrients and Plant Protection Chemicals in the Urban
Environment, M. Nettetal., eds.
Lai, H. 2008. Nutrient Credit Trading: A Market-based Approach for Improving Water Quality.
WNTSC/NRCS/USDA, Portland, OR.
.
Accessed February 23, 2010.
Lanier, L.G., and N. Beasley. 2007. Recycling Urban Stormwater: 1050 K. Street,
Washington, DC. In Proceedings of the Greening Rooftops for Sustainable Communities
Conference, Minneapolis, MN, April 29-May 1, 2007.
Law, N., K. Dibiasi, and U. Ghosh. 2008. Deriving reliable pollutant removal rates for municipal
street sweeping and storm drain cleanout programs in the Chesapeake Bay Basin. Center
for Watershed Protection, Ellicott City, MD.
Law, N.L., L.E. Band, and J.M. Grove. 2004. Nitrogen Input from Residential Lawn Care
Practices in Suburban Watersheds in Baltimore County, MD. Journal of Environmental
Planning and Management 47(5): 737-755.
LCSMC (Lake County Stormwater Management Commission). No date. A Citizen's Guide to
Maintaining Stormwater Best Management Practices for Homeowners Associations and
Property Owners. Lake County Stormwater Management Commission, Waukegan, IL.
. Accessed
February 24, 2010.
Lehman, J.T., D.W. Bell, and K.E. McDonald. 2009. Reduced river phosphorus following
implementation of a lawn fertilizer ordinance. Lake and Reservoir Management.
25(3):307-312. .
Accessed February 24, 2010.
Chapter 3. Urban and Suburban 3-191
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
Limnotech. 2007. The Green Buildout model: Quantifying the Stormwater Management Benefits
of Trees and Green Roofs in Washington, DC. Limnotech, Washington, DC.
Los Angeles County Department of Public Works. 2004. Final Sun Valley Watershed
Management Plan, . Accessed
May 6, 2010.
Maestre, A., R. Pitt, 2005. The National Stormwater Quality Database, Version 1.1, A
Compilation and Analysis ofNPDES Stormwater Monitoring Information. Center for
Watershed Protection, Ellicott City, MD, and U.S. Environmental Protection Agency
Washington, DC.
.
Accessed March 10, 2010.
Marin Municipal Water District Ordinance 326: An ordinance revising water conservation
requirements, Section 11.60.030. August 28, 1991. In A. Vickers. 2001. Handbook of
water use and conservation. WaterPlow Press, Amherst, MA.
Marjorie Barrick Museum. 2010. Turf Conversion. University of Nevada Las Vegas, Las Vegas,
NV. . Accessed February 24, 2010.
Maryland Department of Natural Resources. No date. Trees Save Energy. DNR, Annapolis, MD.
. Accessed February 23,
2010.
Maryland DOE (Department of the Environment). 2000. Maryland Stormwater Design Manual.
Maryland Department of the Environment, Baltimore, MD.
. Accessed February 24, 2010.
Mayer, P.W., and W.B. DeOreo. 1998. Residential End Uses of Water. Aquacraft, Inc., Water
Engineering and Management, and American Water Works Association.
MC (Montgomery County). 2008. Context-sensitive road design standards. Montgomery County,
Maryland, Rockville, MD.
McDonald, O.K. 2004. So/7s for Salmon: Integrating Stormwater, Water Supply, and Solid Waste
Issues in New Development and Existing Landscapes. Center for Watershed Protection,
Ellicott City, MD. Presented at the Water Restoration Institute, September 16, 2004.
MDASS (Maryland Agricultural Statistics Service). 2006. Maryland 2005 Turfgrass Survey. U.S.
Department of Agriculture. National Agricultural Statistics Survey. Maryland Turfgrass
Council. Maryland Field Office, College Park, MD.
3-192 Chapter 3. Urban and Suburban
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
Metropolitan Council. 2009. Urban Small Sites Best Management Practice Manual, Chapter 2:
Selecting BMPs. Metropolitan Council, St. Paul, MN.
. Accessed February
24,2010.
Miami-Dade County, Florida. 2009. Legislative Item File Number: 091097.
. Accessed February 24, 2010.
Milesi, C., C.D. Elvidge, J.B. Dietz, B.J. Tuttle, R.R. Nemani, and S.W. Running. 2005. Mapping
and modeling the biogeochemical cycling of turf grasses in the United States.
Environmental Management 36(3):426^38.
Minnesota Department of Agriculture. 2007. Report to the Minnesota Legislature: Effectiveness
of the Minnesota Phosphorus Lawn Fertilizer Law. St. Paul, MN.
. Accessed February 24, 2010.
Minnesota Department of Agriculture. 2010. Phosphorus Lawn Fertilizer Law. St. Paul, MN.
. Accessed
February 24, 2010.
Mohamed, R. 2006. The Economics of Conservation Subdivisions: Price Premiums,
Improvement Costs, and Absorption Rates. Urban Affairs Re view 41(3): 376-399.
Mosko, S. 2009. No Such Thing as a Green Lawn, . Updated
December 10, 2009. Accessed March 9, 2010.
National Association of Local Government Environmental Professionals, Trust for Public Land,
and ERG. 2003. Smart Growth for Clean Water: Helping Communities Address the Water
Quality Impacts of Sprawl. National Association of Local Government Environmental
Professionals, Washington DC, Trust for Public Land, San Francisco, CA, and ERG,
Boston, MA.
National Cooperative Highway Research Program. 2006. Project 25-20(01): Evaluation of Best
Management Practices for Highway Runoff Control, Low Impact Development Highway
Manual, Oregon State University, Corvallis, OR.
. Accessed February 23,
2010.
National Research Council. 2008. Urban Stormwater Management in the United States. The
National Academies Press and the Committee on Reducing Stormwater Discharge
Contributions to Water Pollution, Washington, DC.
Chapter 3. Urban and Suburban 3-193
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
Natural Resources Defense Council. 2006. Rooftops to Rivers: Green Strategies for Controlling
Stormwater and Combined Sewer Overflows; NRDC, New York, NY.
. Accessed February 24, 2010.
NEMO (Nonpoint Education for Municipal Officials). 2008. A Catalyst for Community Land Use
Change, 2008 Progress Report. National NEMO Network, Haddam, CT.
. Accessed
February 23, 2010.
New Jersey Legislature. Fertilizer Application Model Ordinance.
. Accessed February 24, 2010.
New York State DEC (Department of Environmental Conservation). 2008. New York State
Stormwater Management Design Manual, Chapter 10: Enhanced Phosphorus Removal
Standards. New York State Department of Environmental Conservation, Albany, NY.
. Accessed February 24, 2010.
NJDEP (New Jersey Department of Environmental Protection). 2004. Storm Drain Labeling
Guidelines for New Jersey. New Jersey Department of Environmental Protection, Division
of Watershed Management, Trenton, NJ.
. Accessed
February 24, 2010.
NJDEP (New Jersey Department of Environmental Protection). 2009. New Jersey Stormwater
Best Management Practices Manual. New Jersey Department of Environmental
Protection, Trenton, NJ. .
Accessed February 24, 2010.
NOAA (National Oceanic and Atmospheric Administration). 2009. The Coastal Nonpoint
Pollution Control Program. U.S. Department of Commerce, National Oceanic and
Atmospheric Administration, Washington, DC.
. Accessed February 24,
2010.
North Carolina Coastal Federation. 2008. Low Impact Development Pilot Study to Reduce Fecal
Coliform into Core Sound, Final Report. North Carolina Coastal Federation, Newport, NC.
North Carolina DENR. No date. Division of Pollution Prevention and Environmental Assistance.
North Carolina Division of Pollution Prevention & Environmental Assistance, Raleigh, NC.
. Accessed February 24, 2010.
3-194 Chapter 3. Urban and Suburban
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
Novotney, M., and R. Winer. 2008. Urban Subwatershed Restoration Manual No. 9: Municipal
Pollution Prevention/Good Housekeeping Practices. Center for Watershed Protection,
Ellicott City, MD.
. Accessed
February 24, 2010.
Nowak, D.J., and Crane, D.E. 2000. The Urban Forest Effects (UFORE) Model: quantifying
urban forest structure and functions. In Hansen, M. and T. Burk (eds.) Resources
Inventories in the 21st Century. U.S. Department of Agriculture Forest Service General
Technical Report NC-212: 714-72). St. Paul, MN.
. Accessed February 22,
2010.
NVPDC (Northern Virginia Planning District Commission). 1992. Northern Virginia BMP
Handbook. Northern Virginia Planning District Commission, Fairfax, VA.
. Accessed February 24,
2010.
NVPDC (Northern Virginia Planning District Commission). No date. Virginia's Maintaining Your
BMP: A Guidebook for Private Owners and Operators in Northern Virginia. Virginia
Department of Conservation and Recreation, Richmond, VA.
. Accessed February 24, 2010.
NYASS (New York Agricultural Statistics Service). 2004. New York Turfgrass Survey. National
Agricultural Statistics Service, Albany, NY.
Ocean County Soil Conservation District, Schnabel Engineering Associates, Inc., U.S.
Department of Agriculture-Natural Resources Conservation Service. 2001. Impact of Soil
Disturbance During Construction on Bulk Density and Infiltration in Ocean County, New
Jersey, . Accessed February 25, 2010.
Oro Loma Sanitary Board. 2007. An Ordinance of the Sanitary Board of the Oro Loma Sanitary
District Adopting Civic Green Building and Bay-Friendly Landscaping Requirements. Oro
Loma Sanitary District, Alameda County, CA.
. Accessed February 24,
2010.
P2RX (Pollution Prevention Resource Exchange). 2009. Pollution Prevention Resource
Exchange. Pollution Prevention Resource Exchange, Omaha, NE. .
Accessed February 24, 2010.
Chapter 3. Urban and Suburban 3-195
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
PCDPW (Pierce County Department of Public Works). 2005. Pierce County, Washington's
Stormwater Maintenance Manual for Private Facilities. Pierce County Department of
Public Works, Environmental Services, Water Programs Division, Tacoma, WA.
. Accessed February 24, 2010.
Pennsylvania DEP (Department of Environmental Protection). No date. Technology Acceptance
& Reciprocity Partnership (TARP). Pennsylvania Department of Environmental Protection,
Harrisburg, PA. .
Accessed February 24, 2010.
Philadelphia Water Department. 2009. Summary of Triple Bottom Line Analysis, City of
Philadelphia Long-Term Control Plan. Office of Watersheds, Philadelphia PA.
Accessed February 23, 2010.
Philadelphia Water Department. No date. Green City, Clean Water. Office of Watersheds.
Philadelphia, PA. . Accessed February 23, 2010.
Pitt, R., A. Maestre, and R. Morquecho. 2004. The National Stormwater Quality Database
(NSQD, version 1.1). University of Alabama, Department of Civil and Environmental
Engineering, Tuscaloosa, AL.
. Updated February 16,
2004. Accessed February 3, 2010.
Plan Philly. 2009. Green City, Clean Waters: Philadelphia's Program for Combined Sewer
Overflow Control, A Long-Term Control Plan Update, Summary Report, 2009. University
of Pennsylvania School of Design, Philadelphia, PA. .
Accessed February 23, 2010.
Pomeroy, C.A., and A. Rowney. 2009. User's Guide to the SELECT BMP Model. SW1R06a.
Water Environment Research Foundation, Alexandria, VA.
Portland BES (Bureau of Environmental Services). 2010a. A Sustainable Approach to
Stormwater Management. City of Portland, OR.
. Accessed February 23, 2010.
Portland BES (Bureau of Environmental Services). 2010b. Portland Green Street Program.
Portland Bureau of Environmental Services, Portland, OR.
. Accessed February 23, 2010.
Portland BES (Bureau of Environmental Services). 201 Oc. Tabor to the River. Portland Bureau
of Environmental Services, Portland, OR.
. Accessed February 23, 2010.
3-196 Chapter 3. Urban and Suburban
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
Prince George's County, Maryland. 2009. Annual Report. Prince George's County, MD.
. Accessed February 23, 2010.
Qui, Z., T. Prato, and G. Boehm. 2007. Economic Valuation of Riparian Buffer and Open Space
in a Suburban Watershed. Journal of the American Water Resources Association, paper
No. 04078.
Rancho Cucamonga, California. No date. Xeriscape Requirements.
. Accessed February
24,2010.
Rather, John. March 12, 2009. With Fertilizer Laws, Suffolk Is Aiming for Cleaner Water. New
York Times, . Accessed February 24, 2010.
Reese, A. 2009. Volume-based hydrology: Examining the shift in focus from peak flows and
pollution treatment to mimicking predevelopment volumes. Storm water 10(6).
. Accessed
January 15, 2010.
Riverkeeper. 2008. Sustainable Raindrops: Cleaning New York Harbor by Greening the Urban
Landscape. Riverkeeper, Terrytown, NY. . Accessed February 24, 2010.
Robbins, P., and T. Birkenholts. 2001. Turfgrass Revolution: measuring the expansion of the
American lawn.
. Accessed February 25, 2010.
Rowe, P., and T. Schueler. 2006. The Smart Watershed Benchmarking Tool. Center for
Watershed Protection, Ellicott City, MD.
Saluda-Reedy Watershed Consortium. 2006. Audit of Pavement Standards for the Saluda-
Reedy Watershed, Mitigating the Impacts of Impervious Surfaces in Greenville and
Pickens Counties, South Carolina. Upstate Forever, SC. .
Accessed February 23, 2010.
San Mateo County. 2009. San Mateo County Sustainable Green Streets and Parking Lots
Design Guidebook. San Mateo County, CA.
Chapter 3. Urban and Suburban 3-197
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
Sanibel City Council. 2007. City Approves Environmentally Friendly Regulations for Fertilizer
Use on Island. Sanibel City, FL.
. Accessed February 24, 2010.
Santa Clara Valley Urban Runoff Pollution Prevention Program. 2005. Hydromodification
Management Plan—Final Report. Sunnyvale, CA.
. Accessed February 22, 2010.
Schueler, T. 1995. Site Planning for Urban Stream Protection. Metropolitan Washington Council
of Governments, Washington, DC.
. Accessed February 23,
2010.
Schueler, T. 2000a. Can urban soil compaction be reversed? Article 37 in The Practice of
Watershed Protection, ed. T. Schueler and H. Holland, Center for Watershed Protection,
Ellicott City, MD.
Schueler, T. 2000b. Diazinon sources in runoff from the San Francisco Bay region. Article 16 in
The Practice of Watershed Protection, ed. T. Schueler and H. Holland, Center for
Watershed Protection, Ellicott City, MD.
Schueler, T. 2000c. The compaction of urban soils. Article 36 in The Practice of Watershed
Protection, ed. T. Schueler and H. Holland, Center for Watershed Protection, Ellicott City,
MD.
Schueler, T. 2000d. The peculiarities of perviousness. Article 129 in The Practice of Watershed
Protection, ed. T. Schueler and H. Holland, Center for Watershed Protection, Ellicott City,
MD.
Schueler, T. 2000e. Urban pesticides: From the lawn to the stream. Article 5 in The Practice of
Watershed Protection, ed. T. Schueler and H. Holland, Center for Watershed Protection,
Ellicott City, MD.
Schueler, T. 2007. Urban stormwater retrofit practices. Manual 3. Small Watershed Restoration
Manual Series. U.S. Environmental Protection Agency, Washington, DC, and the Center
for Watershed Protection, Ellicott City, MD
Schueler, T., C. Swann, T. Wright, and S. Sprinkle. 2005. Urban SubwatershedRestoration
Manual No. 8: Pollution Source Control Practices. Center for Watershed Protection,
Ellicott City, MD.
.
Accessed February 24, 2010.
3-198 Chapter 3. Urban and Suburban
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
Schultz, W. 1989. The Chemical-Free Lawn—The Newest Varieties and Techniques to Grow
Lush, Hardy Grass. Rodale Press, Emmaus, PA.
Shearman, R. 2006 Turfgrass Cultural Practices for Water Conservation. In Beard, J.B., and
M.P. Kenna. 2008. Water Quality and Quantity Issues for Turfgrasses in Urban
Landscapes. Council for Agricultural Science and Technology, Ames, IA.
Simpson, T.W., and S.E. Weammert. 2009. Developing Nitrogen, Phosphorus and Sediment
Reduction Efficiencies for Tributary Strategy Practices, BMP Assessment Final Report.
Chesapeake Bay Program, Baltimore, MD.
. Accessed February 24, 2010.
Smart Growth Network. 2010. Principles of Smart Growth. National Center for Appropriate
Technology, Butte, MT.
. Accessed
February 23, 2010.
Smith, W.H. 1990. Air Pollution and Forests. Springer-Verlag, New York, NY.
SMRC (Stormwater Manager's Resource Center). No date. Manual Builder. Stormwater
Manager's Resource Center, Ellicott City, MD. .
Accessed February 24, 2010.
SNWA (Southern Nevada Water Authority). 2010. Water Smart Landscapes Rebate. Southern
Nevada Water Authority, Las Vegas, NV. .
Accessed February 24, 2010.
Soldat, D., A. Petrovic, and Q. Ketterings. 2009. Effect of Soil Phosphorus Levels on Phophorus
Runoff Concentrations from Turfgrass. Water, Air, Soil Pollution 199(1-4):33-44.
Soldat, D., and Petrovic, A. 2008. The Fate and Transport of Phosphorus in Turfgrass
Ecosystems. Crop Science. 48:2051-2065. Published online November 24, 2008.
Souch, C.A., and C. Souch. 1993. The effect of trees on summertime below canopy urban
climates: a case study, Bloomington, Indiana. J. Arboric. 19(5):303-312.
SSMCWPPP (San Mateo Countywide Water Pollution Prevention Program). No date. San
Mateo Countywide Water Pollution Prevention Program. San Mateo Countywide Water
Pollution Prevention Program, San Mateo, CA. . Accessed
February 24, 2010.
Stephenson, K., and B. Beamer. 2008. Economic Impact Analysis of Revisions to the Virginia
Stormwater Regulation, Final Report. Prepared for the Virginia Department of
Conservation and Recreation, Richmond, VA.
Chapter 3. Urban and Suburban 3-199
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
Stephenson, K., C. Speir, L. Shabman, and D. Bosch. 2001. The Influence of Residential
Development Patterns on Local Government Costs and Revenues. Report Papers from
the Virginia Tech Rural Economic Analysis Program.
. Accessed February 23, 2010.
StopWaste.org. 2008. Bay-Friendly Landscape Guidelines: Sustainable Practices for the
Landscape Professional, . Accessed February 9, 2010.
Stormwater Magazine. 2010. Project Profile: Reshaping Downtown Minneapolis. Stormwater
Magazine March/April 2010. . Accessed March 3, 2010
Stranko, S.A., R.H. Hilderbrand, R.P. Morgan II, M.W. Staley, A.J. Becker, A. Roseberry-
Lincoln, E.S. Perry, and P.T. Jacobson. 2008. Brook Trout Declines with Land Cover and
Temperature Changes in Maryland. North American Journal of Fisheries Management
28:1223-1232 doi: 10.1577/M07-032.1
and
. Accessed
February 22, 2010.
Stratus Consulting. 2009. A Triple Bottom Line Assessment of Traditional and Green
Infrastructure, Options for Controlling CSO Events in Philadelphia's Watersheds Final
Report. Stratus Consulting, Inc, Boulder, CO.
. Accessed February 23, 2010.
Strecker, E., M.M. Quigley, and B.R. Urbonas. 2000. Determining urban Stormwater BMP
effectiveness. In Proceedings of the National Conference on Tools for Urban Water
Resources, February 7-10, 2000, Chicago, IL.
Sustainable Conservation. 2010. Brake Pad Partnership. Sustainable Conservation, San
Francisco, CA. . Accessed February 24, 2010.
TerraLogos. 2001. Green Building Template: A Guide to Sustainable Design Renovating for
Baltimore Rowhouses. Maryland Department of Natural Resources, Annapolis, MD.
Tetra Tech. 2008. Stormwater Best Management Practices (BMP) Performance Analysis. Tetra
Tech, Inc., Fairfax, VA.
The Interstate Technology & Regulatory Council. 2009. Phytotechnology Technical and
Regulatory Guidance. The Interstate Technology & Regulatory Council, Washington, DC.
3-200 Chapter 3. Urban and Suburban
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
The Low-Impact Development Center. 2008. Low Impact Development. The Low-Impact
Development Center, Beltsville, MD. . Accessed
February 23, 2010.
Town of Gary, North Carolina. 2009. Cary Offering Incentives for Grass-To-Turf Switch.
. Accessed February 17, 2010.
Town of Edmonston. No date. Project Green Street. Town of Edmonston, MD.
. Accessed February 23,
2010.
Township of Montville. 2010. New Fertilizer Regulations. Morris County, NJ.
.
Accessed February 24, 2010.
Trust for Public Land and American Water Works Association. 2004. Protecting the Source.
Trust for Public Land, San Francisco, CA and American Water Works Association,
Denver, CO.
Trust for Public Land. 1999. The Economic Benefits of Open Space. San Francisco, CA.
. Accessed March
29, 2006.
U.S. Army Corps of Engineers. 2008. Low Impact Development for Sustainable Installations:
Stormwater Design and Planning Guidance for Development within Army Training Areas.
Public Works Technical Bulletin 200-1-62. U.S. Army Corps of Engineers, Washington,
DC.
U.S. Composting Council. 2008. Using Compost in Stormwater Management.
. Accessed February, 25, 2010.
U.S. Department of Agriculture, Agricultural Research Service. No date. National Arboretum
Turf Management. U.S. Department of Agriculture, Agricultural Research Service,
Washington, DC.
U.S. Department of Agriculture. 2000. Resources Inventories in the 21st Century. U.S.
Department of Agriculture Forest Service General Technical Report NC-212 (pp. 714-
720). U.S. Department of Agriculture, St. Paul, MN. .
Accessed February 22, 2010.
U.S. DoD (Department of Defense). 2004. Unified Facilities Criteria (UFC) Low Impact
Development. U.S. Department of Defense, Washington, DC.
. Accessed February 24, 2010.
Chapter 3. Urban and Suburban 3-201
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
U.S. DoD (Department of Defense). 2009. Stormwater management at federal facilities and
federal lands in the Chesapeake Bay watershed. Draft report fulfilling section 202(c) of
Executive Order 13508. U.S. Department of Defense, Washington, DC.
U.S. Fish and Wildlife Service, Chesapeake Bay Field Office. 2009. BayScapes.
. Updated November 3, 2009.
Accessed February 9, 2010.
U.S. Fish and Wildlife Service. 2003. Native Plants for Wildlife Habitat and Conservation
Landscaping: Chesapeake Bay Watershed.
. Accessed February 9, 2010.
U.S. General Services Administration. 2005. Facility Standards for the Public Building Service.
U.S. General Services Administration, Office of the Chief Architect.
. Accessed May 6, 2010.
U.S. Naval Facilities Engineering Command. 2004. Low Impact Development, Draft, Unified
Design Criteria. U.S. Department of Defense, Washington, DC.
. Accessed February 23, 2010.
UPS Project. No date. UP3 Project. Urban Pesticide Pollution Prevention Project, Oakland, CA.
. Accessed February 24, 2010.
USDA (U.S. Department of Agriculture) Natural Resources Conservation Service. 2007. Part
654 Stream Restoration Design National Engineering Handbook. U.S. Department of
Agriculture, Washington, DC.
USEPA (U.S. Environmental Protection Agency) and Prince George's County, Maryland. 1999.
Low-impact Development Strategies, An Integrated Design Approach, U.S. Environmental
Protection Agency, Washington, DC, and Prince George's County, MD.
USEPA (U.S. Environmental Protection Agency) and Prince George's County, Maryland. 2000a.
Low-impact Development Strategies, An Integrated Design Approach, U.S. Environmental
Protection Agency, Washington, DC, and Prince George's County, MD.
USEPA (U.S. Environmental Protection Agency) and Prince George's County, Maryland. 2000b.
Low-Impact Development Hydrologic Analysis. U.S. Environmental Protection Agency,
Washington, DC, and Prince George's County, MD. .
Accessed February 23, 2010.
USEPA (U.S. Environmental Protection Agency) and Prince George's County, Maryland. 2006.
Final Technical Report Phase III. U.S. Environmental Protection Agency, Washington, DC
and Prince George's County, MD.
. Accessed February 23, 2010.
3-202 Chapter 3. Urban and Suburban
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
USEPA (U.S. Environmental Protection Agency) and Prince George's County, Maryland. 2007.
Final Technical Report, Pilot Projects for LID Urban Retrofit Program, In the Anacostia
River Watershed, Phase IV. U.S. Environmental Protection Agency, Washington, DC and
Prince Georges County, Maryland.
. Accessed February 23, 010.
USEPA (U.S. Environmental Protection Agency). 1995. Economic Benefits of Runoff Controls
(U.S. Environmental Protection Agency, Office of Water, Washington, DC.
USEPA (U.S. Environmental Protection Agency). 2000. Liquid Assets. U.S. Environmental
Protection Agency, Washington, DC.
. Accessed February 23, 2010.
USEPA (U.S. Environmental Protection Agency). 2001. Protecting and Restoring America's
Watershed's: Status, Trends, and Initiatives in Watershed Management. U.S.
Environmental Protection Agency, Washington, DC.
. Accessed February 23,
2010.
USEPA (U.S. Environmental Protection Agency). 2003a. Fact Sheet: Water Quality Trading
Policy. U.S. Environmental Protection Agency, Washington DC.
. Accessed February 23,
2010.
USEPA (U.S. Environmental Protection Agency). 2003b. Water Quality Trading Policy.
U.S. Environmental Protection Agency, Washington, DC.
. Accessed
February 23, 2010.
USEPA (U.S. Environmental Protection Agency). 2004a. Stormwater Best Management
Practices Design Guide, Office of Research and Development, Volumes 1-3 (121, 121A,
121B). EPA/600/R-04/121. U.S. Environmental Protection Agency, Washington, DC.
USEPA (U.S. Environmental Protection Agency). 2005b. Stormwater Phase II Final Rule:
Federal and State-Operated MS4s: Program Implementation. EPA 833-F-00-012.
U.S. Environmental Protection Agency, Office of Water.
. Accessed May 6, 2010.
USEPA (U.S. Environmental Protection Agency). 2004c. The Use of Best Management
Practices (BMPs) in Urban Watersheds. EPA/600/R-04/184. U.S. Environmental
Protection Agency, Office of Research and Development, Washington, DC.
Chapter 3. Urban and Suburban 3-203
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
USEPA (U.S. Environmental Protection Agency). 2005a. National Management Measures to
Control Nonpoint Source Pollution from Urban Areas. U.S. Environmental Protection
Agency, Washington, DC. .
Accessed February 24, 2010.
USEPA (U.S. Environmental Protection Agency). 2005b. Using Smart Growth Techniques as
Stormwater Best Management Practices. U.S. Environmental Protection Agency,
Washington, DC.
USEPA (U.S. Environmental Protection Agency). 2006. Protecting water resources with higher
density development. EPA-231-R-06-001. U.S. Environmental Protection Agency, Office
of Water, Washington, DC.
USEPA (U.S. Environmental Protection Agency). 2008a. Memorandum: Underground Injection
Control (UIC) Program Class V Well Identification Guide. U.S. Environmental Protection
Agency, Washington, DC.
Accessed February 24, 2010.
USEPA (U.S. Environmental Protection Agency). 2008b. Case Studies for Stormwater
Management on Compacted, Contaminated Soils in Dense Urban Areas.
U.S. Environmental Protection Agency, Washington, DC.
. Accessed February 24, 2010.
USEPA (U.S. Environmental Protection Agency). 2008c. Design principles for Stormwater
management on compacted contaminated soils in dense urban areas. EPA-560-F-07-231.
U.S. Environmental Protection Agency, Washington, DC.
USEPA (U.S. Environmental Protection Agency). 2008d. Handbook for Developing Watershed
Plans to Restore and Protect our Waters. U.S. Environmental Protection Agency,
Washington, DC.
USEPA (U.S. Environmental Protection Agency). 2008e. National Menu of Stormwater Best
Management Practices. U.S. Environmental Protection Agency, Washington, DC.
. Accessed February 24, 2010.
USEPA (U.S. Environmental Protection Agency). 2008f. Nutrient Criteria Technical Guidance
Manual, Wetlands, U.S. Environmental Protection Agency, Washington, DC., EPA-822-B-
08-001, 2008.
USEPA (U.S. Environmental Protection Agency). 2009a. Managing Wet Weather with Green
Infrastructure Municipal Handbook Incentive Mechanisms. U.S. Environmental Protection
Agency, Washington, DC.
. Accessed March 3,
2010.
3-204 Chapter 3. Urban and Suburban
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
USEPA (U.S. Environmental Protection Agency). 2009b. Nonpoint Source News-Notes.
U.S. Environmental Protection Agency, Washington, DC.
. Accessed February 24, 2010.
USEPA (U.S. Environmental Protection Agency). 2009c. Source Water Protection Practices
Bulletin: Managing Stormwater Runoff to Prevent Contamination of Drinking Water.
U.S. Environmental Protection Agency, Washington, DC.
. Accessed
February 24, 2010.
USEPA (U.S. Environmental Protection Agency). 2009d. Source Water Protection Practices
Bulletin: Managing Highway Deicing to Prevent Contamination of Drinking Water.
U.S. Environmental Protection Agency, Washington, DC.
.
Accessed February 24, 2010.
USEPA (U.S. Environmental Protection Agency). 2009e. Technical Guidance for Implementing
the Stormwater Runoff Requirements for Federal Projects under Section 438 of the
Energy Independence and Security Act of 2008. EPA-841-8-09-001. U.S. Environmental
Protection Agency, Office of Water, Washington, DC.
. Accessed
January 15, 2010.
USEPA (U.S. Environmental Protection Agency). 2009f. Water Quality Scorecard.
U.S. Environmental Protection Agency, Washington, DC.
. Accessed
February 24, 2010.
USEPA (U.S. Environmental Protection Agency). 201 Oa. Education Resources for Non-Point
Source Runoff. U.S. Environmental Protection Agency, Washington, DC.
. Accessed February 24, 2010.
USEPA (U.S. Environmental Protection Agency). 201 Ob. Healthy Watersheds. U.S.
Environmental Protection Agency, Washington, DC.
. Accessed February 24, 2010.
USEPA (U.S. Environmental Protection Agency). 2010c. Protecting Water Resources with
Higher-Density Development. U.S. Environmental Protection Agency, Washington, DC.
. Accessed February 23, 2010.
USEPA (U.S. Environmental Protection Agency). 201 Od. Reducing Stormwater Costs through
Low Impact Development (LID) Strategies and Practices. U.S. Environmental Protection
Agency, Washington, DC. . Accessed February 23, 2010.
Chapter 3. Urban and Suburban 3-205
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
USEPA (U.S. Environmental Protection Agency). 201 Oe. Water Quality Scorecard: Incorporating
Green Infrastructure Practices at the Municipal, Neighborhood, and Site Scale. U.S.
Environmental Protection Agency, Washington, DC.
. Accessed February 23, 2010.
USGS (U.S. Geological Survey). 2003. A Summary Report of Sediment Processes in
Chesapeake Bay and Watershed. U.S. Geological Survey, Reston, VA.
USGS (U.S. Geological Survey). 2006, Rev. 2007. The Quality of the Nations Waters -
Pesticides in the Nation's Streams and Ground Water, 1992-2001. Circular 1291. National
Water-Quality Assessment Program. U.S. Geological Survey, Reston, VA.
Accessed April 29, 2010.
VA OCR (Virginia Department of Conservation and Recreation). 2009a. Runoff Reduction
Method. Virginia Department of Conservation and Recreation, Richmond, VA.
. Accessed February 24, 2010.
VA OCR (Virginia Department of Conservation and Recreation). 2009b. Virginia Stormwater
BMP Clearinghouse. Virginia Department of Conservation and Recreation, Richmond, VA.
. Accessed February 24, 2010.
VAASS (Virginia Agricultural Statistics Survey). 1998. Virginia Turfgrass Industry Profile.
National Agricultural Statistics Service. Virginia Field Office, Richmond, VA.
Vickers, A. 2001. Handbook of water use and conservation. WaterPlow Press, Amherst, MA.
Walsh, J.W., A.M. Roy, J.W. Feminella, P.O. Cottingham, P.M. Grossman, R.P. Morgan II. 2005.
The urban stream syndrome: Current knowledge and the search for a cure. Journal of the
North American Benthological Society. 2005, 24 (3): 706-723.
Waring, B. 2007. Gateway Center's Green Roof is Among County's First. NIH Record LIX(16).
. Updated August
10, 2007. Accessed April 30, 2010.
Washington State Department of Ecology. 2005. Stormwater Management Manual for Western
Washington: Volume IV—Source Control BMPs. Washington State Department of
Ecology, Olympia, WA. . Accessed February
22,2010.
Washington State Department of Ecology. 2009. Evaluation of Emerging Stormwater Treatment
Technologies. Washington State Department of Ecology, Olympia, WA.
. Accessed
February 22, 2010.
3-206 Chapter 3. Urban and Suburban
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
Weinstein, N., C. Glass, J.P. Heaney, J. Lee, W. Huber, P. Jones, C. Kloss, M. Quigley, E.
Strecker, and K. Stephens. 2005. Decentralized Stormwater Controls for Urban Retrofit
and Combined Sewer Overflow Reduction. Water Environment Research Foundation,
Alexandria, VA.
Weinstein, N., J. Getting, D. Nees, S. Downing, J. Lee, B. Tauber, A. English, C. Kloss, C.
Glass, W.C. Huber, and T. Morgan. 2009. Decentralized Stormwater Controls for Urban
Retrofit and Combined Sewer Overflow Reduction, Phase II. Water Environment Research
Federation, Alexandria, VA.
WERF (Water Environment Research Foundation). 2005a. Critical Assessment of Stormwater
Treatment and Control Selection Issues. Water Environment Research Foundation,
Alexandria, VA.
WERF (Water Environment Research Foundation). 2005b. Performance and Whole-Life Costs
of Sustainable Urban Drainage Systems. Water Environment Research Federation,
Alexandria, VA.
WERF (Water Environment Research Foundation). 2006. Infiltration vs. Surface Water
Discharge: Guidance for Stormwater Managers, Final Report. Water Environment
Research Foundation, Alexandria, VA.
WERF (Water Environment Research Foundation). 2006-2007. Green Infrastructure Design
Considerations. Water Environment Research Foundation, Alexandria, VA.
. Accessed February 24, 2010.
WERF (Water Environment Research Foundation). 2008a. Protocol for Studying Wet Weather
Impacts and Urbanization Patterns. Water Environment Research Foundation, Alexandria,
VA.
WERF (Water Environment Research Foundation). 2008b. Using Rainwater to Grow Livable
Communities. Water Environment Research Foundation, Alexandria, VA.
. Accessed February 24, 2010.
WERF (Water Environment Research Foundation). 2009. WERF Cost Tool, 2009. Free
spreadsheet tool developed as part of Performance and Whole Life Cost of Best
Management Practices and Sustainable Urban Drainage Systems (2005). Water
Environment Research Federation, Alexandria, VA.
. Accessed February 22,
2010.
Whatcom County. 2009. Establishing Regulations for Fertilizer Application on Residential Lawns
and Public Properties within the Lake Whatcom and Lake Samish Watersheds. Whatcom
County, WA. . Accessed
February 24, 2010.
Chapter 3. Urban and Suburban 3-207
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
Wiess, P.T., J.S. Gulliver, and A.J. Erickson. 2005. The Cost and Effectiveness ofStormwater
Management Practices. Minnesota Department of Transportation, Minneapolis, MN.
Wilbe, C.J. 2010. Comment attachment submitted by Chris J. Wible, Director, Environmental
Stewardship, The Scotts Miracle-Gro Company. Comment on Proposed Rule: Executive
Order 13508 Chesapeake Bay Protection and Restoration Section 502 Guidance: Federal
Land Management in the Chesapeake Bay Watershed. Docket ID: EPA-HQ-OW-2010-
0164.
. Updated April 26, 2010. Accessed April 29, 2010.
Wisconsin State Legislature. 2009. Assembly Bill 3. Madison, Wl.
. Accessed February 24, 2010.
Woodworth, J.W. Jr. 2002. Out of the Gutter. Natural Resources Defense Council, New York,
NY. . Accessed February 23, 2010.
Wright, T., C. Swann, K. Cappiella and T. Schueler. 2005. Urban Subwatershed and Site
Reconnaissance Users Guide. Manual 11, Appendix C. Center for Watershed Protection,
Ellicott City, MD.
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
Appendix 1: BMP Fact Sheets
1.1 Introduction
The BMPs included in this document are not an exhaustive list but represent some examples of
low-impact development (LID) practices that have been widely adopted and have proven to be
effective in managing stormwater, and where there is new information on existing practices,
such as street sweeping. The fact sheets contain technical information and references and are
written to be applicable to federal facilities and nonfederal facilities.
Practices such as stormwater detention and hydrodynamic settling devices have an important
role in stormwater management and are effectively described in many existing sources (for
references, see Section 3). The practices presented in this appendix were selected because
they represent newer approaches to stormwater management (such as green roofs or
bioretention) or new technologies (such as blue roofs and cisterns) or where new information
exists on existing technologies (such as bioretention).
The following BMP fact sheets were prepared for this document because new information is
available that is relevant to application in the Chesapeake Bay watershed and potentially
elsewhere. Each fact sheet includes a description of the practice, targeted pollutants,
photos/diagrams, constraints/limitations, effectiveness, design, maintenance, and costs. Equally
important practices that are already well-described on EPA's Web site are not repeated here;
instead, links to them are provided below.
Practices with fact sheets in Appendix 1 consist of the following:
1.2 Rainwater harvesting
1.3 Green roofs
1.4 Blue roofs
1.5 Bioretention
1.6 Infiltration
1.7 Soil restoration
1.8 Reforestation/urban forestry
1.9 Street sweeping
1.10 Constructed wetlands
Chapter 3. Urban and Suburban 3-209
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
Practices with fact sheets on EPA's Web site consist of the following:
• Downspout disconnection • Brownfield redevelopment
• Planter boxes • Infill and redevelopment
• Rain gardens • Green parking
• Permeable pavements • Pocket wetlands
• Vegetated swales • Compost Blanket
EPA's Green Infrastructure Web site:
http://cfpub.epa.gov/npdes/greeninfrastructure/technology.cfm
EPA's Menu of BMPs Web site:
http://cfpub.epa.gov/npdes/stormwater/menuofbmps/index.cfm?action=min measure&min mea
sure id=5
1.1.1 Performance Estimate Summaries for Infiltration Practices
The performance of LID practices varies significantly by the design and the regional climate. In
the Chesapeake Bay region, a large infiltration BMP relative to the drainage area could provide
infiltration of the 95th percentile storm event or more. The slower infiltration rates of clay type
soils results in the need for more storage, but they also have an ability to infiltrate. For additional
discussion, see the bioretention fact sheet.
The performance of several of these infiltration practices was recently reviewed for the
Chesapeake Bay region to estimate the capability for volume control and pollutant reduction
based on the design criteria used in the region (which was not developed to manage the 95th
percentile storm event). The Mid-Atlantic Water Program housed at the University of Maryland
led a project during 2006-2009 to review and refine definition and effectiveness estimates for
BMPs in the Chesapeake Bay watershed. (Developing Best Management Practice Definitions
and Effectiveness Estimates for Nitrogen, Phosphorus, and Sediment in the Chesapeake Bay,
December 2009 (BMP Effectiveness Report)
www.chesapeakebay.net/websitesearchresults.aspx?menuitem=19557). The urban stormwater
BMPs reviewed by the Mid-Atlantic Water Program are at
http://archive.chesapeakebay.net/pubs/BMP ASSESSMENT REPORT.pdf. The LID BMPs
reviewed and their definition as reported in the BMP assessment are as follows:
Bioretention: An excavated pit backfilled with engineered media, topsoil, mulch, and vegetation.
These are planting areas installed in shallow basins in which the storm water is temporarily
3-210 Chapter 3. Urban and Suburban
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
ponded and then treated by filtering through the bed components, and through biological and
biochemical reactions within the soil matrix and around the root zones of the plants.
Permeable Pavement and Pavers: Pavement or pavers that reduce runoff volume and treat
water quality through both infiltration and filtration mechanisms. Water filters through open voids
in the pavement surface to a washed gravel subsurface storage reservoir, where it is then
slowly infiltrated into the underlying soils or exists via an underdrain.
Infiltration Trenches and Basins: A depression to form an infiltration basin where sediment is
trapped and water infiltrates the soil. No underdrains are associated with infiltration basins and
trenches, because by definition these systems provide complete infiltration.
Filters: Filters capture and treat runoff by filtering through a sand or organic media.
Vegetated Open Channels: Open channels are practices that convey stormwater runoff and
provide treatment as the water is conveyed, includes bioswales. Runoff passes through either
vegetation in the channel, subsoil matrix, and/or is infiltrated into the underlying soils.
The effectiveness summary from the BMP Assessment Report is provided in Table 3A1-1. The
BMP Assessment Report provides a summary of assumptions, data sources, maintenance
consideration, and other factors related to these LID practices in the Chesapeake Bay area.
Among the assumptions used in preparation of the effectiveness estimates were
• That the estimates reflect performance that might actually be expected where persons
less-specialized in bioretention prepare the design, and install and operate the BMP,
according the design criteria used in the region. This estimates average performance.
This was intentionally not based on data from controlled research studies on practices
designed, built, and maintained by bioretention experts. This does not reflect
performance of systems designed to achieve retention of the 95th percentile storm event.
• That the BMPs were designed for a 1-inch storm; at approximate 1 inch to 1.5 inches,
the system would begin to overflow. (1.5 inches of rainfall is approximately the 95th
percentile rain event in the Chesapeake Bay area.)
• Lined bioretention cells were reported to have poorer performance; the presence of the
liner reduces performance to approximately that of C/D soils with an underdrain.
In reviewing the effectiveness values in this table, it is important to note the variability in the
estimates, that the estimates are intended to be conservative, and that the majority of the
pollutant removal is associated with the volume reduction that occurs from either infiltration or
Chapter 3. Urban and Suburban 3-211
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
evapotranspiration. For additional information on performance estimates, refer to the
Bioretention/Biofiltration fact sheet.
Table 3A1-1. Effectiveness summary from the BMP assessment report
Bioretention
C/D soils, underdrain
A/B soils, underdrain
A/B soils, no underdrain
Filter
All (sand, organic, peat)
Vegetated Open Channels
C/D soils, no underdrain
A/B soil, no underdrain
Bioswale
Permeable Pavement (no sand/veg)
C/D soils, underdrain
A/B soils, underdrain
A/B soils, no underdrain
Permeable Pavement (with sand, veg)
C/D soils, underdrain
A/B soils, underdrain
A/B soils, no underdrain
Infiltration Practices (no sand/veg)
A/B soils, no underdrain
EMC-based
removal (PR)
TP
37
37
37
60
10
10
37
10
10
10
10
10
10
25
TIM*
10
10
10
40
10
10
10
0
0
0
10
10
10
0
TSS
50
50
50
80
50
50
50
50
50
50
50
50
50
95
Runoff
reduction
(RR)
15
65
80
0
0
40
65
10
45
75
10
45
75
80
Mass-based removal
(TR) expressed as
removal from
collection areas (acres)
TP
45
75
85
±20
60
±10
10
45
±20
75
±20
20
50
80
±20
20
50
80
±20
85
±15
TN
25
70
80
±15
40
±15
10
45
±20
70
±15
10
45
75
±15
20
50
80
±15
80
±15
TSS
55
80
90
±15
80
±10
50
70
±30
80
±15
55
70
85
±15
55
70
85
±15
95
±10
3-212
Chapter 3. Urban and Suburban
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
Table 3A1-1. Effectiveness summary from the BMP assessment report (continued)
Infiltration Practices (with sand/veg)
A/B soils, no underdrain
EMC-based
removal (PR)
TP
25
TIM*
15
TSS
95
Runoff
reduction
(RR)
80
Mass-based removal
(TR) expressed as
removal from
collection areas (acres)
TP
85
±10
TIM*
85
±15
TSS
95
±10
Source: Simpson, T., and S. Weammert. 2009. Developing Best Management Practice Definitions and Effectiveness
Estimates for Nitrogen, Phosphorus, and Sediment in the Chesapeake Bay. Final Report.
Notes:
1. Soil classification (A, B, C, D) per U.S. Department of Agriculture (USDA) National Resource Conservation Service
(NRCS)
2. EMC-based removal expressed as Percent Reduction (PR)
3. Mass-based removal expressed as percent removal of total load by mass (TR)
4. Nitrogen concentration reduction is low potentially because the solubility of nitrate, the potential for organic nitrogen and
ammonia to mineralize in the bioretention media to the nitrate form, and the lack of conditions needed for denitrification
contribute to nitrogen export.
5. Assumptions include (1) highly impervious urbanized land use; (2) generalized for design criteria typical of bay area
jurisdictions; (3) designed, installed and maintained by persons who are not experts in bioretention; 3) low phosphorus
soil media; (4) for systems designed for a 1-inch storm, rain events from 1 to 1.5-inch depth will begin to show overflow
6. Total removal estimated by the calculation TR = RR + {(100-RR) x PR)}, rounded to a factor of 5.
7. Authors caution that the estimates, based on limited data and generalized for simplicity, might not represent true long-
term performance throughout the watershed. Performance is highly variable even under controlled conditions.
Chapter 3. Urban and Suburban
3-213
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
Rainwater harvesting can play an important role in managing stormwater runoff and can reduce both the
costs and energy needed to convey and treat runoff offsite. Rain barrels and cisterns can be used to
reduce runoff volume and mitigate peak runoff flow rates for small and medium storm events. Rainwater
collected in harvesting systems is typically only used for nonpotable applications, such as irrigation, toilet
flushing, and vehicle washing, but uses could expand as demand for water increases. In addition to
reducing stormwater runoff, rainwater harvesting has the secondary benefit of reducing potable water
demand because nonpotable uses represent up to 40 percent of overall household water demand.
Rooftop runoff, because it typically contains low pollutant loads and is easily collected, is the source of
most water collected in rainwater harvesting systems.
Harvested rainwater can be routed and stored in two main types of vessels called cisterns or rain barrels.
Cisterns generally have a much larger capacity than rain barrels. Cisterns can be designed to hold hundreds
or thousands of gallons. Rain barrels most often hold between 55-250 gallons with 55- to 75-gallon barrels
being the most commonly used sizes. To capture the rainwater, roof downspouts are piped to the rain
barrel or cistern. Most residential rain barrels are installed outside as are many cisterns. However,
cisterns can be installed inside residential and non-residential buildings, outside and above or below
grade. Bypass drains or systems are used to divert excess volume when the rain barrel or cistern is full.
Some systems require the use of filtration or disinfection systems depending on the intended use and the
size of the system. Rain barrels typically do not require such systems. Filtration and disinfection systems
are used to reduce fouling, clogging, bacterial growth, slime formation and to treat the rainwater for its
intended uses.
In most areas of the country, the use of rain barrels and cisterns is for water supply. They are also
encouraged mainly to reduce the volume of runoff discharged from impervious surfaces, such as to help
mitigate localized flooding or combined sewer overflows. In arid or semi-arid areas or areas of period
drought rainwater harvesting systems can play an important role in the provision of supplemental
irrigation or wash waters. Around the globe, rainwater collection systems are often used to provide
potable water. In the United States the use of harvested rainwater for potable uses is restricted due to
public health concerns.
Rainwater harvesting systems are most effectively used to reduce runoff volume when they are integrated
into a treatment train or system of practices that can include green roofs, permeable pavements or rain
gardens/bioretention cells.
To optimize system performance, the system should be managed either manually or automatically to
discharge the captured volume before the next significant storm event occurs. Such management
strategies help to ensure that the maximum cistern/rain barrel capacity is available when a rain event
occurs. For example, soaker hoses can be used with rain barrels to slowly drain the rain barrel in periods
of non-irrigation use and automatic real-time control systems can be used for large non-residential
systems to control the timing of and the release rate of water from the cistern to ensure capacity is
available to capture the next storm.
3-214 Chapter 3. Urban and Suburban
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
Hydrologic Performance and Targeted Pollutants
Hydrologic Performance
Volume Reduction
®1
Peak Flow Reduction
®a
Groundwater Recharge
Oa
Key: • High effectiveness ® Medium effectiveness OLow effectiveness
a The effectiveness depends on how the water is managed after capture,
i.e., slowly released to a storm sewer, used for infiltrating irrigation, etc.
Targeted Pollutants
Sediment
0
Nitrogen
0
Phosphorus
0
Metals
0
Oil & Grease
0
Bacteria
0
Temperature
0
Key: • High effectiveness ® Medium effectiveness O Low effectiveness
Photos and Diagrams
TYPICAL RAINWATER HARVESTING SYSTEM
GUTTER
DEBRIS &
MOSQUITO
SCREEN
OPTIONAL SECONDARY WATER
- SUPPLY FROM CITY WATER
(AS PER BULDENG CODE)
OVERFLOW
OVERFLOW TO
VEGETATED AREA
NOT TO SCALE
Source: NC Division of Water Quality. Technical Guidance: Stormwater Treatment Credit for Rainwater Harvesting Systems
Figure 3A1-1. Typical rainwater harvesting system
Chapter 3. Urban and Suburban
3-215
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
• Requires a dedicated plumbing system for indoor use.
• Optimal performance requires active management to ensure that storage containers are emptied
between storms.
• Local ordinances can restrict downspout disconnection or indoor use of harvested water.
The volume retained in a storm event is determined by the size of the storage container and its available
volume at the time of the storm. Careful operation of the system to ensure that cisterns and rain barrels
drain completely prior to a rain event can help to maximize the available volume. The use of real-time
control systems can increase performance significantly.
Pollutant removal by rainwater harvesting is minimal, and is generally limited to settling of suspended
solids. Water quality can degrade in a cistern if bacteria are allowed to grow.
Sizing is based on rainfall patterns, drainage area, water demand, and space and/or budgetary
constraints. Cisterns should be sized to store water from multiple events, or to empty between events, if
capacity for back-to-back storms is needed.
Proper cistern capacity is calculated by balancing the expected rainfall volume with the anticipated water
demand. Additional capacity could be incorporated to allow extended storage of rainwater for use during
dry periods.
Design considerations include the following:
• Piping for harvested rainwater should be labeled to prevent accidental use for potable
applications.
• Rain barrels and cisterns should be fitted with emergency overflows.
• Cisterns constructed belowground must be fitted with pumps to deliver collected water.
• Systems for indoor uses such as toilet flushing should be dual piped with potable water for back-
up. A backflow prevention assembly should be used to prevent cross-contamination of the
potable supply line. Local building codes should be consulted.
• Pretreatment might be desired before storage to prevent fouling of the storage tank. Screening,
settling of suspended solids, and oil and grease separation (for parking lot runoff) might be
beneficial. The first flush of runoff can be diverted from the storage tank to remove debris.
• Treatment requirements for stored rainwater vary by municipality and intended end use. Typically,
no treatment is required for outdoor irrigation, while filtration and/or UV disinfection might be
required for indoor nonpotable uses.
• Outdoor cisterns should be screened at each opening to prevent insects from entering.
3-216 Chapter 3. Urban and Suburban
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
American Rainwater Catchment Systems Association/American Society of Plumbing Engineers issued
Rainwater Catchment Design and Installation Standards (August 2009) to assist in properly and safely
implementing systems. Several localities have implemented or adopted standards as part of their building
codes.
A typical maintenance schedule is provided in Table 3A1-2. Maintenance needs will vary by the type of
system and location.
Table 3A1-2. Rainwater harvester maintenance schedule
Activity
Inspect and clean filters and screens
Inspect and clear debris from roof, gutters,
downspouts, and roof washers, and other
rainwater harvesting areas
Remove tree branches and vegetation
overhanging roof or other above-ground
rainwater harvesting areas
Inspect pumps, valves, and pressure tanks and
verify operation
Inspect cistern(s) and system labeling
Inspect backflow prevention system
Cross-connection inspection and test
Minimum frequency
Before the first storm event and every 2 months
during the wet season
Before the first storm event and every month during
the wet season
As needed
After initial installation and annually at the beginning
of the wet season
After initial installation and annually at the beginning
of the wet season
After initial installation and annually at the beginning
of the wet season or as required by LACDPH
After initial installation and annually at the beginning
of the wet season or as required by LACDPH
Source: Federico, etal. Geosyntec Consultants, Technical Memorandum: Large-Scale Cistern Standards, Report to Los
Angeles County Department of Public Works, December 2009.
Fifty-five-gallon rain barrels typically cost $50-$100 for prefabricated units, or $30 for do-it-yourself kits.
For cistern tanks, costs depend on the material used for construction, and costs are similar to other water
storage tank systems (Table 3A1-3). A tool for estimating tank and pump costs is available from the
Water Environment Federation (WERF), the User's Guide to the BMP and LID Whole Life Cost Model,
Version 2.0, and associated spreadsheet tool.
Chapter 3. Urban and Suburban
3-217
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
Table 3A1-3. Cistern tank costs
Cistern tank cost by type ($/gallon, installation not included), 2009
Fiberglass
10, 000 gal and up
$ 1.33
Steel
500-1 5, 000 gal
$ 2.51
Plastic
50-1 ,500 gal
$ 1.43
Concrete
2,000 gal and up
$ 1.66
Source: WERF BMP and LID Whole Life Cost Model, Version 2.0
Costs for large cistern systems are dependent on many site-specific factors, such as whether excavation
is required for underground units. Cost items applicable to systems used for irrigation can include
• Piping and pretreatment (screening)
• Tank, pumps, valves
• Site preparation
• Concrete pad for above ground; excavation for buried
Example system costs are provided in Table 3A1-4.
Table 3A1-4. Summary of cistern system costs with project characteristics
Site
Landscape Architecture13
Library, Tucson, AZ
Fairmount Square13
Grand Rapids, Ml
Redbud Center13
Austin, TX
Santa Monica Main13
Library, CA
Mark Miller Toyota2b
Salt Lake City, UT
Hypothetical Office2
Building, Arlington, VA
Open Charter Elementary,
Westchester CA2b
Hall House, Los Angeles,
CA1
Center for Community
Forestry, Los Angeles,
CA1
Capacity
(gallons)
11,600
30,000
31,000
200,000
1 @ 8,000
1 @ 2,000
10,000
110,000
3,600
216,000
Construction
material
Steel and Fiberglass
Concrete
Steel
Concrete
Concrete
Fiberglass
Modified RainStoreS
Infiltration System
Polypropylene
Concrete
New/retrofit
year installed
New 2007
New
New 2008
New 2006
New 2008
New 2008
New 2004
Retrofit 1998
New 2008
Location
Above-
ground
Buried
Above-
ground
Buried
Buried
Buried
Buried
Partially
Buried
Buried
Estimated cost
$17,000
(total cost)
$40,000
(total cost)
$250,000
(total cost)
$700,000
(total cost)
$22,000
(total cost)
$179,000
(estimated total)
$500,000
(not incl. design)
$25,000
(installed)
$400,000
(excludes soft costs,
distribution system)
a Federico et al. 2009. Technical Memorandum: Large-Scale Cistern Standards. Prepared for Los Angeles County
Department of Public Works, by Geosyntec Consultants.
b Water Environment Research Foundation. 2009. User's Guide to the BMP and LID Whole Life Cost Model, Version 2.0.
3-218
Chapter 3. Urban and Suburban
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
American Rainwater Catchment Systems Association, www.arcsa.org
Cabell Brand Center. 2009. Virginia Rainwater Harvesting Manual, Version 2.0. Salem, VA. (Draft Form)
www.cabellbrandcenter.org: http://cabellbrandcenter.org/RWH Manual2009.pdf
Credit Valley Conservation. 2008. Credit River Stormwater Management Manual. Mississauga, Ontario;
www.creditvalleyca.ca/sustainabilitv/lid/stormwaterguidance/index.html
Federico, et. al. Geosyntec Consultants. 2009. Technical Memorandum: Large-Scale Cistern Standards,
Report to Los Angeles County Department of Public Works.
Georgia Department of Community Affairs. 2009. Georgia Rainwater Harvesting Guidelines, Draft.
Gowland, D., and T. Younos. 2008. Feasibility of Rainwater Harvesting BMP for Stormwater Management.
Virginia Water Resources Research Center. Special Report SR38-2008. Blacksburg, VA
North Carolina Division of Water Quality. 2008. Technical Guidance: Stormwater Treatment Credit for
Rainwater Harvesting Systems. Revised September 22, 2008. Raleigh, NC.
http://h2o.enr.state.nc.us/su/documents/RainwaterHarvesting Approved.pdf
North Carolina State University, Biological and Agricultural Engineering. Urban Waterways: Permeable
Pavements, Green Roofs, and Cisterns.
www.bae.ncsu.edu/stormwater/PublicationFiles/BMPs4LID.pdf
Seattle, Washington, Department of Planning and Development. 2009. Rainwater Harvesting for
Beneficial Use, Client Assistance Memo 520.
Texas A&M University, AgriLife Extention Service, http://rainwaterharvesting.tamu.edu/index.html
Texas Water Development Board. 2005. The Texas Manual on Rainwater Harvesting—Third Edition.
U.S. Environmental Protection Agency, Office of Water. 2008. Municipal Handbook: Rainwater Harvesting
Policies, www.epa.gov/npdes/pubs/gi munichandbook harvesting.pdf
Virginia Department of Conservation and Recreation, Design Specification No.6 and Design Spreadsheet
www.chesapeakestormwater.net/storage/first-draft-baywide-design-
specificationsi/BAYWIDE%20No%206%20RAIN%20TANKS%20AND%20CISTERNS.pdf
Water Environment Research Federation. 2009. User's Guide to the BMP and LID Whole Life Cost
Model, Version 2.0.
Chapter 3. Urban and Suburban 3-219
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
Green roofs attenuate flow and provide storage and evapotranspiration of stormwater. They are typically
designed with an impermeable membrane that is root resistant, an engineered soil medium, plants, and in
many cases an underdrain system. Some green roofs also have leak detection systems. The design of
green roof systems significantly impacts performance. The two main categories of green roof designs are
• Extensive, which have a shallow planting media layer (typically 2-6 inches) and low-growing,
drought tolerant plants.
• Intensive, which have a deeper media layer, and can be planted with a wider variety of plants,
including trees and shrubs. Intensive green roofs can be fitted with walkways and used as
recreational areas.
Rain falling onto green roofs is both detained and retained in the soil medium. When the soil medium
becomes saturated, the excess water percolates through to the drainage layer and is discharged through
the roof downspouts. In between storm events, water absorbed by the soil media is returned to the
atmosphere by evapotranspiration. Depending on the design and climate pattern of the region, green
roofs can provide significant stormwater volume reduction on an annual basis, decrease peak flow rates,
and help to restore hydrologic function of the watershed by absorbing and attenuating runoff.
In addition to providing stormwater retention, green roofs can be designed to provide ancillary benefits,
such as enhancing site aesthetics, urban habitat for birds and insects, reduction of urban heat island
effects, insulation value for energy conservation and increasing the longevity of roofing materials.
Green roofs are common in Europe, but have only recently gained popularity in US as a practice for
mitigating stormwater runoff. The International Green Roofs Projects Database (www.greenroofs.com')
lists over 1,000 green roof projects, mainly in the United States.
Hydrologic Performance
Volume Reduction
•
Peak Flow Reduction
®
Groundwater Recharge
O
Key: • High effectiveness ® Medium effectiveness O Low effectiveness
Targeted Pollutants
Sediment
0
Nitrogen
0
Phosphorus
0
Metals
®
Oil & Grease
0
Bacteria
0
Temperature
®
Key: • High effectiveness ® Medium effectiveness O Low effectiveness
3-220
Chapter 3. Urban and Suburban
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
Photos and Diagrams
Source: The Low Impact Development Center
Figure 3A1-2. ASLA headquarters green roof.
VtGtlAliON
GROWING MEDIUM
DRAINAGE. AERATION. WATER
STORAGE AND ROOT BARRIER
STRUCTURAL
SUPPORT (ROOF
MEMBRANE PROTECTI'
AND ROOT BARRIER
ROOFING MEMBRANE
Source: MDE Stormwater Design Manual
Figure 3A1-3. Green roof section.
Common Feasibility Constraints and Limitations
• Slopes when using the more typical construction practices are generally less than 30 percent.
Installations on pitched roofs require stabilization structures to prevent migration of the soil
medium. Specialized drains are typically required for slopes above 5 percent.
Chapter 3. Urban and Suburban
3-221
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
• Roofs must be able to bear the load of a fully saturated medium. Extensive green roof wet weight
is approximately 6 to 7 pounds per square foot per inch of depth.
• Construction costs include transporting materials to a roof, which could require a crane.
• Costs of green roof construction are typically higher than other LID practices (such as
bioinfiltration or blue roofs) for a water-volume reduction. However, it has been shown to be cost-
effective when other factors are considered, such as energy savings, and also has other benefits
to the public, including reduction of urban heat island effect, particularly in dense urban areas
(Portland Bureau of Environmental Services 2008).
Runoff volume removal is a function of the green roof area, the specifics of the green roof design, and the
local climate and rainfall pattern. Green roofs can retain the full volume of small storms, and they are
commonly designed to detain brief periods of high intensity rainfall. Reported results for extensive roofs
are summarized in Table 3A1-5.
Table 3A1-5. Performance estimates for annual flow retained, summer flow retained, and peak flow
shaving for green roofs
Performance
Measure
Annual Flow
Retained
Summer Runoff
Peak Flow
Shaving
Performance3
Estimate
50%
75%
65-70%
56%
26% - 86%
95%
30% to 96%
60%
Location
Philadelphia
Washington, D.C.
East Lansing, Ml
Portland, OR
National Range
Philadelphia
National Range
Portland, OR
Depth of Media
(not including submedia
layers)
3.5 to 4 inches
3-18 inches
1 -2.4 inches
5 inch
Various
3.5 to 4 inches
5 inch
Source
USEPA 2009
Glass 2007
VanWoert 2005
Portland BES 2008
Portland BES 2008
USEPA 2009
Portland BES 2008
Portland BES 2008
a Performance as measured over the time period as a whole, not for a specific event, for example, not for the 96th percentile
storm event, but for that 96% of the total rainfall over the time period was retained.
Pollutant removal in green roofs is strongly dependent on the specifics of the design, and on rates of
atmospheric deposition. Studies have shown that green roofs do not often provide pollutant reductions;
however, it is noted that the concentration of pollutants in direct rainfall is very low (therefore, there is
relatively little pollutant to remove). Temporary export of nutrient can occur during initial establishment of
the media and plants. Poorly designed green roof soil media can lead to export of low concentrations of
nutrients and solids from the media, fertilizer and plants. For this reason, it is preferable to discharge the
runoff from green roofs into bioretention or other unit if pollutant reduction is needed in addition to the
volume reduction (EPA 2009). Green roofs, however, have been shown to export lower levels of
pollutants than conventional roofs. Material selection is an important consideration. Many roofing
materials can export toxic chemicals that can be used in their construction (Clark et al. 2008).
3-222
Chapter 3. Urban and Suburban
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
Green roofs are most often constructed on flat or shallow sloped roofs, but roofs with slopes up to 30
percent accommodate green roofs with the use of mesh, stabilization panels, or battens. The area
covered by green roofs is typically limited to 50-80 percent of the total roof area due to the need to
accommodate HVAC (heating, ventilation and air conditioning) or other equipment (e.g. cell towers or
solar panels) and roof access or other penetrations. Green roofs have also been designed to
accommodate solar panels.
A typical green roof profile would include the following layers:
• Vegetation layer
• Engineered growth media
• Separation geotextile
• Semi-rigid plastic geocomposite drain or mat
• Root barrier
• Waterproofing membrane
Plant Selection—Plant selection varies depending on the type of green roof installed. Extensive green
roofs should be planted with low-growing, drought tolerant plants, such as succulents. Sedums are
frequently used. Intensive green roofs, which have deeper soil media, can accommodate a much wider
variety of plants, including trees and shrubs. Intensive green roofs often require irrigation to support the
larger plants.
Soil medium—To minimize the potential for nutrient export, the soil medium should have a high mineral
content. Use of compost has been found to produce elevated levels of nitrogen and phosphorus in
effluent, at least in the short term (Moran et al. 2004).
Maintenance requirements vary depending on design specifics, with extensive green roofs typically
requiring less maintenance than intensive green roofs. Maintenance typically includes
• Periodic irrigation during plant establishment and dry periods.
• Periodic weeding, fertilization (if needed), and infill planting
• Periodic inspection of drainage outlets and waterproof membrane.
Cosies .ant! '"BGtoTi An'ftciMjit Coeit
Costs depend on the media depth, the number and type of additional structural components in the design,
the vegetation selected, and the need for structural roof modifications. Costs for extensive green roofs
typically range from $8-$14 per square foot (PADEP 2006). The installation cost of the green roof is
partially offset by increasing the life of the underlying roof, and reducing heating and cooling demand
within the building.
Chapter 3. Urban and Suburban 3-223
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
Costs were reported to vary primarily by the installation type (WERF 2009; Portland BES 2008):
• Modular, tray-type installations: $19.50 per square foot
• Custom applications with media spread across the surface: $8.75 per square foot
Green roofs reduce energy costs and extend roof life. Green Roofs for Healthy Cities
(www.qreenroofs.orq') provides a calculator to estimate the long term savings.
A cost-benefit analysis of a hypothetical green roof concluded that green roofs had a higher net present
value for the owner and the public, despite higher initial capital and O&M costs (Portland BES 2008). Not
all benefits were examined, but areas where economic benefits accrued include
• For the public: (1) Reduced Stormwater Quantity; (2) Avoided Stormwater Infrastructure;
(3) Improved Air Quality; (4) Enhanced Habitat
• For the owner or developer: (1) Reduced Stormwater Fees; (2) Extended Roof Life; (3) Increased
floor-to-area (FAR) allowance allowing more floors and higher buildings; (4) Reduced energy
costs.
US General Services Administration (GSA). 2009. Guideline Scope of Work, Design Build Guidance
Criteria Retrofitting Low-slope Roofs with a Vegetative Roof System.
Pennsylvania Department of Environmental Protection (PADEP). 2006. Pennsylvania Stormwater Best
Management Practices Manual, Document Number: 363-0300-002, BMP 6.5.1: Vegetative Roof.
www.elibrary.dep.state.pa.us/dsweb/View/Collection-8305
New York State Department of Environmental Conservation. New York State Stormwater Management
Design Manual, Draft Chapter 4.3.8 Green Roofs. December 2009.
Whole Building Design Guide. Extensive Green Roof Resources Page.
www.wbdq.org/resources/qreenroofs.php?r=site potential#rcas
ASTM International. 2006. Standard Guide for Selection, Installation and Maintenance of Plants for Green
Roof Systems. Standard E2400-06. ASTM International. West Conshohocken, PA.
.
Berhage, R., A. Jarrett, D. Beattie and others. 2007. Quantifying evaporation and transpiration water
losses from green roofs and green roof media capacity for neutralizing acid rain. Final Report.
National Decentralized Water Resource Capacity Development Project Research Project.
Pennsylvania State University.
3-224 Chapter 3. Urban and Suburban
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
Clark, S., B. Long, C. Siu, J. Spicher and K. Steele. 2008. Early-life runoff quality: green versus traditional
roofs. Low Impact Development 2008. Seattle, WA. American Society of Civil Engineers.
Dietz, M.E. 2007. Low-Impact Development Practices: A Review of Current Research and
Recommendations for Future Directions, Water, Air, Soil Pollution, 186; 351-363.
Dunnett, N. and N. Kingsbury. 2004. Planting Green Roofs and Living Walls. Timber Press. Portland,
Oregon.
Glass, Charles C. 2007. Green Roof Water Quality and Quantity Monitoring, Howard University
Department of Civil Engineering, University Park, MD.
Green Roofs for Healthy Cities (www.greenroofs.org')
International Green Roofs Projects Database (www.greenroofs.com')
MDE (Maryland Department of Environment). 2008. Chapters. Environmental Site Design. Green Roofs.
Moran, A., W. Hunt and G. Jennings. 2004. Greenroof research of stormwater runoff quantity and quality
in North Carolina. NWQEP Notes. No. 114. North Carolina State University. Raleigh, NC.
North Carolina State University (NCSU). 2008. Green Roof Research Web Page. Department of
Biological and Agricultural Engineering, www.bae.ncsu.edu/greenroofs.
Portland BES (Bureau of Environmental Services). 2008. Cost Benefit Evaluation ofEcoroofs, City of
Portland, Oregon.
Snodgrass, E., and L. Snodgrass. 2006. Green Roof Plants: a resource and planting guide. Timber Press.
Portland, OR.
USEPA (U.S. Environmental Protection Agency) 2009. Green Roofs for Stormwater Control, EPA/600/R-
09/026. www.epa.gov/nrmrl/pubs/600r09026/600r09026.pdf.
Van Woert, N., D. Rowe, A. Andersen, C. Rugh, T. Fernandez and L. Xiao. 2005. Green roof stormwater
retention: effects of roof surface, slope, and media depth. Journal of Environmental Quality
34:1036-1044.
Weiler, S. and K. Scholz-Barth 2009. Green Roof Systems: A Guide to the Planning, Design, and
Construction of Landscapes over Structure. Wiley Press, New York, NY.
Water Environment Research Federation. 2009. User's Guide to the BMP and LID Whole Life Cost
Model, Version 2.0.
Chapter 3. Urban and Suburban 3-225
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
A blue roof is a roof design that is explicitly intended to provide temporary storage and slow release of
stormwater runoff. In many locations, these approaches are also referred to as rooftop detention. They
are most commonly used in dense urban areas where other methods of stormwater detention are
impractical. Blue roofs are used to detain rooftop runoff onsite and reduce the rate of runoff from rooftops
during rainfall events. A blue roof can be used as a stand-alone detention method. Or, because they do
little to improve the water quality of runoff, they can be part of a treatment train that includes other LID
and conventional BMPs such as bioretention, infiltration, or wetland systems to shave peak flows and
provide temporary storage to enhance the function, improve the performance, and reduce the cost of
those practices. Blue roofs are one of the least expensive means for temporarily detaining stormwater on
site and can be used where green roofs are not feasible, cost effective or otherwise desired due to
competing needs.
The four primary blue roof types are described below:
• Roof-integrated Designs—Roof-integrated designs are built during new construction or as
modifications of existing roofs to intentionally store standing water over extended periods.
These designs use a roofing membrane or waterproofing system as the primary water detention
structure. Therefore water is temporarily ponded directly on the roof surface. Roof integrated
designs can be designed to store water as an open water surface or partially or completely within
a porous media.
In addition, structures such as walkways, decks, or plazas can be constructed on top of roof
integrated designs to minimize the impact of ponded water on roof access. Alternatively, porous
media such as flexible paving tiles or granular media can be used as a permeable walking
surface on all or part of the roof to allow for access, while reducing the amount of standing open
water.
Roof-integrated designs can be constructed as a secondary roofing layer on top of an existing
surface in the same manner as a physical root barrier in green roof designs.
• Modular Tray Designs—Modular tray systems use plastic trays to temporarily detain water during
rainfall events and release this water over some period of time following a rainfall event. This
approach provides flexibility in both the size and configuration of the detention system and is,
therefore, well-suited for retrofit designs. Equipment and other roof penetrations can be avoided
through selective placement of the trays. Loading issues can be addressed though optimal
density and placement configurations. The trays can be physically attached to the roof or
underlying supporting grid and/or held in place with ballast composed of coarse stone or other
weighed materials. The depth of the ballast or media contained in the trays can be varied
depending on the desire to reduce the presence of open water surfaces.
Modular trays can have any number of different outlet designs according to the goals of the
installation (e.g., reduce peak flows, achieve specific lag time for target events, etc.). When the
water is released, the drainage system for the existing roof continues to function as it did prior to
3-226 Chapter 3. Urban and Suburban
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
the retrofit (i.e., hydraulic head and flow depths on the roofing surface during rainfall are not
increased).
Modular tray blue roof designs can be selectively mixed with green roof components to improve
aesthetics and provide some of the additional benefits of green roofs. The most challenging
component of blue roof tray designs is the robustness of the hydraulic outlet design. Consistent
and reliable drainage of the trays with little maintenance is a key consideration. Some designs
allow for trays to be interconnected to effectively act as a larger tank.
• Roof-Dams/Roof-Checks—Roof-dams or roof-checks are impermeable or semi-permeable
interim breaks in the surface flow paths installed on existing or new roofs that allow water to pond
behind them as temporary detention. The dams can incorporate specific overflow or outlet
designs to slowly release the stored water. In the same manner as a roof-integrated design, the
roof is used as the primary water detention structure with the flows being restricted by the roof-
dams. If retrofit onto existing roofs, the ability of the roof to accept additional ponding should be
assessed and addressed. In older roof installations new roofing and additional water proofing
might need to be installed in conjunction with the installation of the dams.
• Actively Controlled Systems—Blue roofs that are used for temporary rooftop storage can be
classified as active or passive depending on the types of control devices used to regulate
drainage of water from the roof. Passive designs use hydraulic structures such as weirs, orifice
plates or hydraulic regulators to control release rates from the roof. Active approaches allow for
the use of a valve configuration and controller to regulate discharge of flows from rooftops.
The simplest design for an actively controlled blue roof is the retrofit or installation of a
pneumatically or hydraulically actuated pinch valve on the roof leader drain pipe. This valve can
be connected to a low cost micro-controller, which monitors hydraulic head on the valve and
timing of storage on the roof surface. The controller can be programmed to release the ponded
water according to some predetermined optimal approach on the basis of analysis of the
receiving storm sewer, downstream BMP, or receiving water. More complex designs can
integrate communications with server-side and/or internet based data feeds, or telemetry to
optimize release timing and quantities.
Blue roofs can be implemented effectively on shallowly sloped roofs in residential, manufacturing,
commercial or industrial settings. Rooftop detention is a particularly good storage option in densely
developed areas where roofs make up a significant portion of the total site area.
Blue roofs are well-suited to applications on commercial and residential buildings, which typically have
large, flat roofs and little or no area available for storage on site surrounding the building. Such large roofs
generate significant runoff quantities. Rooftop detention using blue roofs represents a cost effective and
convenient storage option that can be applied to new construction in the urban environment to provide
adequate storage volume and runoff reduction to comply with stormwater regulations.
In addition to applications in densely developed areas, blue roof storage techniques also lend themselves
well to implementation on sites with moderate to large flat roofs where flow from impervious non-roof area
(e.g. parking lots, walkways, etc.) also contributes to the total runoff. In these situations, blue roofs are
used to control rooftop runoff, while subsurface BMPs are used to control runoff from non-roof areas. The
use of rooftop storage on such sites reduces the required volume for subsurface systems and allows
these systems to be constructed over a smaller area.
Chapter 3. Urban and Suburban 3-227
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
Key advantages include
• Often the least expensive means for temporarily storing storm water at a site particularly when
compared to subsurface storage or green roof systems.
• Can reduce the size and/or improve the performance of downstream BMPs, such as bioretention
cells of infiltration systems.
• Easy to install—no additional excavation is required, additional construction could be minimal
depending on the depth of water to be stored.
• Existing commercially available products for flow control.
• Readily coupled with other storage techniques, such as subsurface or surface storage.
Hydrologic Performance and Targeted Pollutants
Hydrologic Performance
Volume Reduction
O
Peak Flow Reduction
•
Groundwater Recharge
O
Key: • High effectiveness ® Medium effectiveness O Low effectiveness
Targeted Pollutants
Sediment
O
Nitrogen
O
Phosphorus
O
Metals
O
Oil & Grease
O
Bacteria
O
Temperature
O
Key: • High effectiveness ® Medium effectiveness O Low effectiveness
Photos and Diagrams
Source: with permission from the New York City Department of Environmental Protection
Figure 3A1-4. Rooftop detention being used to control runoff at a commercial property.
3-228
Chapter 3. Urban and Suburban
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
• Storage using outlet controls limited to flat roofs or roofs with shallow slopes (e.g., < 1 percent)
due to increased ratio of ponding depth to available volume for steeper slopes. This problem can
be addressed through the use of modular tray designs or roof-dams.
• Limited benefit on sites where roof area makes up only a small portion of total impervious area.
• Regular maintenance varies by design, but is an important consideration. Verification of system
performance might be necessary.
• Potential tampering must be considered in design.
• Pest problems must be avoided through proper design and maintenance, e.g., mosquitoes.
• Local building codes should be checked to ensure designs are compliant.
Because blue roof designs generally hold less than four inches of ponded water on the roof for times
ranging from a few minutes to many hours, blue roofs typically do not impact the availability of roof space
for other uses.
If such water ponding is incompatible with anticipated future uses of the roof, the blue roof can be
designed to occupy a portion of the roof area, leaving additional roof space available for other purposes.
If structures and equipment are mounted to the roof within the area intended for ponding water, it might
be necessary to provide additional waterproofing around the structure or equipment or to elevate the
equipment above the anticipated maximum water depth to prevent damage and provide access for
maintenance. Where roofs are intended to be used as means of egress or points of rescue for fire safety,
walkway pavers should be provided to allow for safe passage to fire escapes from the roof surface. These
pavers provide a dry walking surface to allow for safe movement through ponded water. In addition,
decks, walkways or pavers can be incorporated into the design of a rooftop detention system to provide
space on the rooftop for passive recreational use.
The application of blue roof systems is most effective on roofs with a maximum slope of about 1/8 inch
per foot (or 1 percent slope) or those with drainage configurations that can safely allow for the necessary
volume detention.
To prevent clogging, the owner should inspect drains and clear snow and ice as necessary after winter
precipitation events in accordance with established maintenance procedures. As with conventional flat
roofs, maintenance procedures for blue roof systems include the removal of accumulated snow prior to an
anticipated rain event to prevent possible overloading. Homeowners or building maintenance staff can
remove snow from the blue roof using the same removal methods used for conventional flat roofs.
Blue roofs primarily provide a means for temporarily detaining water. Little direct impact on water quality
can be achieved through the use of blue roofs alone. Some evaporation will occur in systems that detain
water for extended periods. Evaporation rates on blue roofs approach pan evaporation rates. Pan
evaporation rates can be significant under certain climatic conditions (e.g., hot, windy, low humidity days).
Chapter 3. Urban and Suburban 3-229
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
Blue roofs are most often constructed on flat or shallowly sloped roofs, but tray and roof dam designs can
be used on slopes in excess of 5 percent. On roof integrated designs where the roof is sloped, even very
shallow slopes dramatically reduce detention capacity. Typically in retrofit situations the roof is
reconstructed as a part of blue roof installation. With tray designs, that might not be necessary. The
designer must pay close attention to roof system manufacturer's requirements to ensure that the roofing
system and design are compatible with manufacturer's warrantees and with the blue roof design.
Maintenance for most blue roof systems are similar to those required for typical flat roofing drainage
systems and involve occasional snow and ice removal, regular inspection for debris clogging inlets, and
inspection and repair of the roof.
Blue roofs are one of the least expensive means for temporarily detaining stormwater on site. The
marginal cost of adding a blue roof to new construction is typically less than $2 per gallon of temporary
storage where structural modifications to building design are not required (e.g., designs take into account
snow loads). As new approaches (e.g., tray designs) gain wider acceptance in the marketplace it is
expected that blue roof detention can drop below $1 per gallon of temporary storage.
City of Valparaiso, Indiana. 2004. Stimson Drain Stormwater Management Study Phase II Report,
Appendix B, Rooftop Storage.
www.valparaisoutilities.orq/stormwater/ssph2/StimsonDrain/Appendices/AppendixB/25%20-
%20rooftop%20storaqe%20040915.pdf
Georgia Stormwater Management Manual; Volume Two: Technical Handbook. 2001.
www.qeorqiastormwater.com
Guidebook of Best Management Practices for Michigan Watersheds, Reprinted October, 1998, Roof Top
Storage Pages RTS-1 And RTS-2 in Best Management Practices For Construction Sites, Urban
Areas and Golf Courses, www.michiqan.qov/documents/deq/deq-wb-nps-lntro 250601 7.pdf
Iowa Statewide Urban Design Standards Manual. 2009. www.iowasudas.org/desiqn.cfm
Ontario Stormwater Management Planning & Design Manual, 2003.
www.ene.qov.on.ca/envision/qp/4329eindex.htm
Pennsylvania Stormwater Best Management Practices Manual, BMP 6.8.2: Special Detention Areas—
Parking Lot, Rooftop.
www.stormwaterpa.org/assets/media/BMP manual/chapter 6/Chapter 6-8-2.pdf
3-230 Chapter 3. Urban and Suburban
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
Bioretention cells are small-scale, vegetated, shallow depressions that are used to reduce runoff volumes
and pollutants through the process of soil filtration, interception, vegetative uptake, biological processes,
infiltration, retention and evapotranspiration. Bioretention cells can be used as stand alone systems or as
part of a treatment train. Bioretention cells are typically designed with native soils and or/an engineered
soil mix, and plants that are selected to be tolerant of a range of wet and dry conditions. In some cases
site conditions or design goals might require the use of gravel for additional volume retention or the use of
overflow devices. Where groundwater recharge is required, bioretention can help protect the quality of
infiltrated stormwater. Bioretention typically has no underdrain or liner, both significantly reduce volume
reduction performance.
Biofiltration allows for an underdrain, with only partial or no infiltration achieved, for applications such as
where a discharge is desirable or infiltration is to be avoided.
• The use of soil-based, vegetated systems have distinct advantages over the use of nonbiological
infiltration trenches or similar designs for the following reasons (Davis et al. 2009):
• Roots promote media permeability.
• Surface vegetation can be used to slow stormwater flows and filter sediments.
• Roots support microbial populations needed for pollutant biodegradation.
• Phytoremediation uptakes and breaks down pollutants.
It is recommended that, where feasible, designs use a variety of hardy native plants that are adapted for
both wet and dry soil conditions to ensure long-term plant survival and vigor. If native plants are not
available, the use of nonnative, noninvasive species that typically do not require fertilizer, irrigation or pest
control except at establishment is appropriate.
Bioretention cells can be used in a wide set of applications in the built environment to manage runoff from
roofs, lawns, and streets and other impervious areas such as parking lots and sidewalks. Bioretention
practice typically fall in to the following categories:
• Residential rain gardens
• Tree boxes (common and expanded) and shrub bioretention cells
• Sidewalk or right of way planter boxes
• Parking lot islands
• Street curbs extensions and bump-outs.
• Wooded bioretention areas
• Bioretention swales
Chapter 3. Urban and Suburban 3-231
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
Hydrologic Performance and Targeted Pollutants
Hydrologic Performance For Design Storm Events
Volume Reduction
•
Peak Flow Reduction
•
Groundwater Recharge
•
Key: • High effectiveness ® Medium effectiveness OLow effectiveness
Targeted Pollutants
Sediment
•
Nitrogen
®
Phosphorus
®
Metals
•
Oil & Grease
•
Bacteria
®
Temperature
•
Key: • High ® Medium O Low
Photos and Diagrams
Source: Larry Coffman, Prince George's County, Somerset Subdivision
Figure 3A1-5. Bioretention cell for street and yard drainage.
3-232
Chapter 3. Urban and Suburban
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
Source: Abby Hall, USEPA
Figure 3A1-6. An urban bioretention system treats sidewalk and road runoff.
-width varies-
n^
Mulch
Bioretention soil media
Drainage fabric
AASHTO #7
4" perf. underdrain, '/i" openings *
AASHTO #57
Existing subsoil
3
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
6- to 9-inch maximum ponding
Filter media 2- to 4-foot
depth typical
Filter layer of sand or pea gravel
#57 gravel
Underdrain (optional)
Source: Urban Watershed Forestry Manual, Part 2, CWP and USDA, 2006
Figure 3A1-8. Wooded bioretention can increase pollutant uptake and requires specific design
modifications for tree growth and avoiding engineering conflicts.
3-234
Chapter 3. Urban and Suburban
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
3" COMPOST
BIORETENTION SOIL, 12"MIN
NATIVE SOIL
3" DEPTH COMPOST
BIORETENTION SOIL, 12" MIN
NATIVE SOIL
SWALE TOP WIDTH
BIORETENTION SWALE
SWALE TOP WIDTH
ii X~°-
; T ss f
So]
i
^^- tL.
V
1 "tfT e
i* ^
^ ^°A
\
r
BERM (IF NEEDED),!'MIN
COMPACTED NATIVE SOIL
BERM (IF NEEDED)
COMPACTED NATIVE SOIL
LINER OR SOIL BARRIER IF
DIRECTED BY ENGINEER
MINERAL AGGREGATE TYPE 26
SLOTTED STORM DRAIN, 6" MIN
MIN MIN
BIORETENTION SWALE WITH
SLOTTED STORM DRAIN
Source: Seattle Public Utilities
Figure 3A1-9. Bioretention swales with and without underdrain.
Chapter 3. Urban and Suburban
3-235
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
STRUCTURAL
WALL
FILTER FABRIC
Source: Portland Bureau of Environmental Services
Figure 3A1-10. Infiltration planter box.
Source: Brown 2009
Figure 3A1-11. Bioretention with internal water storage volume.
3-236
Chapter 3. Urban and Suburban
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
Bioretention practices should not be used in some applications, including
• Slopes are greater than 20 percent.
• Hot spots that have a high potential for groundwater contamination, e.g., gas station runoff or
areas where chemicals are stored or managed.
• Large drainage areas from impervious areas greater than 15,000 square feet (unless a system of
separate cells is used to manage the runoff).
• Areas of shallow bedrock or high water tables where infiltration is not feasible (note: design
modification can be used to compensate for these conditions where surface retention is desired).
• Applications that have high sediment loadings unless use pretreatment systems and/or increase
maintenance.
Stormwater infiltration can affect groundwater quality; however, the incidence of groundwater
contaminated to an unhealthy level from stormwater is low. Many factors contribute to the risk (Clark et al.
2009).
Volume Reduction. The amount of volume reduction achievable is a function of design; for example,
selecting a storm depth and designing the cell to capture this volume in the ponding area and upper soil
void space. To determine the annual volume reduction achieved, the likelihood for back-to-back storm
events and seasonal temperature variations should be considered, and continuous modeling is used for
this analysis (USEPA 2008). Guidance manuals are referenced in this fact sheet, and by state and local
jurisdictions, that provide instruction on methods for calculating volume reduction on the basis of
infiltration rates and storage volumes. Evapotranspiration also provides some volume reduction. The
following factors influence the annual stormwater volume reduction achievable:
• Local climate and rainfall patterns.
• Local soil characteristics, including the soils underlying the constructed bioretention cell.
• Local evapotranspiration rates driven by climate conditions, vegetation type, and length of
growing season.
• Site conditions such as location in a sunny area or in deep shade.
• Ratio of cell media volume to drainage area. Increasing the volume of media relative to the
drainage area has been demonstrated to reduce outflow.
• Use of underdrains or liners or both versus infiltration to underlying soil. The use of underdrains
or liners can significantly reduce volume reduction performance. If an underdrain is used, adding
an internal storage zone below the underdrain improves performance, allowing more time for
infiltration, and potentially denitrification (see Figure 3A1-11).
• Care during construction to ensure construction site erosion does not clog the system.
Chapter 3. Urban and Suburban 3-237
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
Pollutant Reduction. Pollutant concentration reductions can be obtained through biofiltration to further
reduce overall loading. Many factors associated with the pollutants, water, soil, plants, microbes, and
system design affect pollutant removal performance.
For example, nutrient removal can be influenced by the following factors:
• The amount of organic material and the potential for the media to decay and leach nutrients.
• The form of phosphorus or nitrogen as it enters the cell, and transforms in the cell.
• Biological transformation of nutrients in microbial and plant processes.
• Cation exchange capacity and ability to sorb nutrients.
• The presence of an anaerobic/saturated zone which influences denitrification potential
• Soil media composition and volume.
• Plant species, community composition, size, coverage and health.
Phosphorus removal requires the use of a low phosphorus index soil mix with a high cation exchange
capacity (Li et al. 2009). Layering of media targeted at specific pollutants can enhance water quality
benefits (Li et al. 2009).
A summary of some pollutant specific removal information is provided below (Davis et al. 2009):
• Suspended Solids—Reductions can be as high as 99 percent. New facilities might initially export
TSS from the washout of fines in the media.
• Phosphorus—Reduction is highly variable, typically from 50 to 80 percent. Effluent phosphorus at
some locations has been higher than influent concentrations, largely due to high initial levels of
soil phosphorus.
• Nitrogen—Because of the complex interactions of nitrogen species, total nitrogen removal is
difficult to achieve. Nitrogen removal might be increased with the use of a higher percentage of
organic matter in the soil mix (Hinman et al. 2005), provided the organic matter does not contain
high nitrogen concentrations. Bioretention can remove organic nitrogen in the media's organic
material. Nitrate, however, is very mobile, and only when the media remains saturated for an
extended period denitrification possible.
• Heavy Metals—Dissolved and particulate-bound metals are removed by filtration of particulate
metals and adsorption of dissolved species in the mulch and bioretention media. Metals have
been shown to be primarily removed in the first 1 to 2 inches of the surface mulch layer (Hinman
et al. 2005).
• Oil & Grease—Adsorption of low concentrations of motor oil to organic material in the soil mix
have resulted in removal efficiencies of 96-99 percent. Native bacteria in the mulch can
biodegrade the hydrocarbons overtime.
• Chlorides—Bioretention does not treat chlorides and, where exposed to salting practices, has
been found to leach chlorides year round.
3-238 Chapter 3. Urban and Suburban
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
• Bacteria—Removal of bacteria have been monitored to be between 70 percent (Hathaway and
Hunt 2008) and 91 percent, through process that include filtration, drying, and exposure to
sunlight.
The reductions in mass loading of N and P achievable with bioretention have been shown to be a result of
the decrease in runoff volume, not necessarily decreases in concentration. Field tests have shown
considerable mass reductions to be achieved even when increases in concentrations occur across the
bioretention cell from nutrients contained in the media (Hunt et al. 2006). For this reason, a volume
reduction performance goal is recommended. Understanding the ranges of effluent concentrations
observed, though, is valuable to evaluate performance.
Typical influent and effluent concentration ranges. The range of observed concentrations of nutrients
in stormwater runoff in the National Stormwater Quality Database is provided in Table 3A1-6, to give an
indication of influent concentration ranges.
Table 3A1-6. Selected median concentration of nitrogen and phosphorus pollutants from urban
land uses
Residential
Commercial
Industrial
Freeways
Open Space
NH3
(mg/L)
0.32
0.5
0.5
1.07
0.18
N02+N03
(mg/L)
0.6
0.6
0.73
0.28
0.59
Nitrogen, Total Kjeldahl
(mg/L)
1.4
1.6
1.4
2
0.74
Phosphorus, total
(mg/L)
0.3
0.22
0.26
0.25
0.31
Source: Pitt, R., A. Maestre, and R. Morquecho. 2004. The National Stormwater Quality Database (NSQD, version 1.1).
University of Alabama, Department of Civil and Environmental Engineering, Tuscaloosa, AL.
http://rpitt.ena.ua.edu/Research/ms4/Paper/Mainms4paper.html. Updated February 16, 2004. Accessed February 3, 2010.
For effluent quality from bioretention, the following are noted:
• Effluent concentration goals of the New York State Design Manual, Chapter 10 Enhanced
Phosphorus Removal (Quigley et al. 2008)
- less than or equal to 0.1 mg/L TP.
- less than equal to 0.06 mg/L dissolved phosphorus.
• Reported effluent concentration results from field studies in the Mid-Atlantic (Davis et al. 2009)
- from 0.06 to 0.56 mg/L TP.
- from 0.08 to 2.8 mg/L TN.
Cold weather performance. Bioretention can provide effective infiltration in cold weather. Dietz and
Clausen (2007) report that, despite measureable frost, 99 percent of runoff was either evapotranspirated
or infiltrated for bioretention in Connecticut. The University of New Hampshire reports similar favorable
performance in winter conditions (Roseen et al. 2009), and rapid thawing of bioretention media is
reported when runoff enters.
Chapter 3. Urban and Suburban
3-239
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
The volume reduction achievable is based on the system design and local climate pattern. Systems can
be design to retain and infiltrate a specific storm depth, with the excess volume either bypassing or
overflowing the system. To determine the annual volume reduction achieved, continuous modeling can be
used. For example, in Stormwater Best Management Practices (BMP) Performance Analysis (USEPA
2008), performance curves are generated on the basis of a given design specification, the soil infiltration
rate, depth of runoff treated, and land use type for a specific climate area, in this case the New England
region. Using that approach, it is possible to select a design storm to approximately achieve a desired
annual volume reduction goal.
A wide range of performance results have been observed in field tests, and authors cite the difficulty of
using such data to prepare general performance estimates (Dietz 2007; Li and Davis 2009; Davis et al.
2009). Volume reductions from 75 percent to greater than 90 percent on an annual average basis have
been reported with bioretention (Geosyntec Consultants, Urban Stormwater BMP Performance
Monitoring, International Stormwater BMP Database, WERF/ASCE/EPA 2009); these values typically
reflect precipitation patterns of the study area where most of the annual rainfall occurs in small events of
approximately an inch depth or less. For understanding and comparing performance results, estimates
should be for an annual basis using long-term, region-specific weather data for a specific design scenario.
Performance estimates provided in Table 3A1-7 for hypothetical average bioretention installations in the
Chesapeake Bay watershed lead to the following observations (Simpson et al. 2009):
• The majority of the load reduction is from runoff reduction, therefore reporting the runoff reduction
component is essential for understanding system performance (Center for Watershed Protection
and Chesapeake Stormwater Network 2008).
• Volume reduction can be a surrogate for, or approximate indicator of, the pollutant removal
achieved.
Several design considerations influence the overall performance of bioretention, including
• The potential for clogging should be assessed and pretreatment, such as mulch, should be
provided if necessary. If grass swales are used, care should be taken to ensure that sediment will
not accumulate to the point where it overtakes the vegetation and becomes costly to remove.
• Well-draining soils allow for rapid infiltration, but if the infiltration rate is too rapid, nitrate can pass
though without treatment.
• Soils with slow infiltration rates can decrease the overall Stormwater volume retention. Infiltration
tests at the site should be performed to better estimate expected performance. In these
conditions, if a specified volume is to be retained, the designer should consider designing the
subbase with gravel or other materials to retain the requisite volume.
• When conditions necessitate the use of underdrains the discharge rate should be as slow as
feasible to maximize infiltration. Overflows are preferred to maintain maximum infiltration. Other
options include positioning the discharge orifice above the bottom of the invert, with an upturned
elbow outlet configuration (Brown 2009).
3-240 Chapter 3. Urban and Suburban
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
Table 3A1-7: Generalized bioretention performance estimates for the Chesapeake Bay Area
demonstrate that the majority of the load reduction is from runoff reduction
Bioretention
C/D soils, underdrain
A/B soils, underdrain
A/B soils, no underdrain
EMC Based Removal
(PR)
TP
37
37
37
TIM*
10
10
10
TSS
50
50
50
Runoff Reduction
(RR)
15
65
80
Mass Based Removal
(TR)
expressed as removal from
collection area (acres)
TP
45
75
85
+20
TN
25
70
80
+15
TSS
55
80
90
+15
Source: Chesapeake Bay Program, Tom Simpson, Sarah Weamert et al. 2009
Notes:
1. Soil classification (A, B, C, D) per USDA National Resource Conservation Service (NRCS)
2. Event Mean Concentration-based Removal expressed as Percent Reduction (PR)
3. Mass Based Removal expressed as percent removal of total load by mass (TR)
4. Nitrogen concentration reduction is low potentially because the solubility of nitrate, the potential for organic nitrogen
and ammonia to mineralize in the bioretention media to the nitrate form, and the lack of conditions needed for
denitrification contribute to nitrogen export.
5. Assumptions included: 1) highly impervious urbanized land use; 2) generalized for design criteria typical of Bay area
jurisdictions; 3) designed, installed and maintained by persons who are not experts in bioretention; 3) low phosphorus
soil media; 4 ) for systems designed for a 1" storm, rain events from 1" to 1.5" depth will begin to show overflow
6. Total removal estimated by the calculation TR = RR + {(100-RR) * PR)}, rounded to a factor of 5.
7. Authors caution that the estimates, based on limited data and generalized for simplicity, might not represent true long-
term performance throughout the watershed. Performance is highly variable even under controlled conditions.
• An impermeable liner, with an underdrain, can be used to prevent infiltration of stormwater from
the biofiltration cell, for example, if soil contamination is suspected. These systems provide water
quality improvements because of the pollutant reductions available from the vegetated system
and moderate volume reductions from evapotranspiration.
Typical maintenance activities are as follows:
• Supplemental irrigation might be needed during the first 2 to 3 years after planting. Drought-
tolerant species might need little additional water after this period, except during prolonged
drought, when supplemental irrigation can become necessary for plant survival.
• Weeds should be removed by hand until vegetation is established. Although plants might need
pruning to maintain healthy growth, routine mowing should not be required. Dead or diseased
plants should be removed and replaced. Mulch should be re-applied when erosion is evident to
maintain a 2-3 inch depth.
• Inspect at least two times per year for sediment buildup, trash removal, erosion, and to evaluate
the vegetation. Sediment should be removed in a manner that minimizes soil disturbance if
Chapter 3. Urban and Suburban
3-241
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
buildup reaches 25 percent of the ponding depth. Ensure pretreatment devices, if used, are
maintained.
• Some manuals recommend replacing the top few inches of bioretention media every few years
and/or when infiltration rates slow down too much.
Costs vary according to many factors including soil depth, plant selections, slope conditions and the
contractor's familiarity with the practice. Typically costs are (WERF, User's Guide to the BMP and LID
Whole Life Cost Model, Version 2.0, and associated spreadsheets, 2009)
• For residential rain gardens: Between $6 per square foot (installed by the owner) to $16 per
square foot of rain garden surface area (professional installed).
• For urban curb-contained bioretention, $16-$29 per square foot, driven by the cost of curbing and
other urban-related infrastructure that can be used for conventional landscaping.
• Bioretention cells often replace areas that would have been landscaped, so the life-cycle cost can
be less than the landscaped alternative.
Some factors influencing costs are
• Material availability and transport
• Site conditions (e.g., traffic, utilities)
• Underdrains that might be selected if the subgrade soils infiltrate poorly; an overflow is typically
less costly while providing better volume-removal performance
• Specific stormwater management requirements, such as enhanced nutrient removal
• The need for, and the type of, pretreatment
• Vegetation type and scale
• Soil medium specifications and availability
• Size of installation
The Prince George's County Bioretention Manual (2007) and WERF's BMP and LID Whole Life Cost
Model (2009) provide reported costs and templates to facilitate project cost estimation.
Delaware Department of Environmental Resources and Environmental Control, Green Technology:
Standards, Specifications, and Details forBMPs, Sections 2.4 and 2.5, 2005.
Pennsylvania Stormwater Best Management Practices Manual, BMP 6.4.5 Rain Garden/Bioretention,
2006.
3-242 Chapter 3. Urban and Suburban
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
Prince George's County, Maryland, Bioretention Manual, Revised December 2007; and Low-Impact
Development Design Strategies: An Integrated Design Approach, EPA 841-B-00-003, 2000.
Prince George's County, Maryland, Low-Impact Development Hydrologic Analysis, EPA 841-B-00-002,
2000.
U.S Fish and Wildlife Service, Bayscapes, www.fws.gov/ChesapeakeBav/Bayscapes.htm
Virginia Department of Conservation and Recreation, Stormwater Design Specification No. 9:
Bioretention, 2009.
Brown, Robert A; William F. Hunt; Shawn G. Kennedy. 2009 Designing Bioretention with an Internal
Water Storage (IWS) Layer. North Carolina State University, North Carolina Cooperative Extention.
Available at: http://www.bae.ncsu.edu/stormwater/PublicationFiles/IWS.BRC.2009.pdf (Accessed
March 22, 2009)
Caltrans. 2002. Draft Biofilter Pilot Phosphorus Investigation.
Center for Watershed Protection and Chesapeake Stormwater Network. 2008. Technical Memorandum:
The Runoff Reduction Method.
Clark, Shirley; R. Pitt, R. 2009. Field Groundwater Contamination Potential from Infiltration of Urban
Stormwater Runoff.
Colwell, Shanti R., R.R. Horner, D. B. Booth. 2000. Characterization of Performance Predictors and
Evaluation of Mowing Practices in Biofiltration Swales, Center for Urban Water Resources
Management, Seattle, WA.
Davis, Allen P., W.F. Hunt, R.G. Traver, and M. Clar. 2009. Bioretention Technology: Overview of Current
Practice and Future Needs, Journal of Environmental Engineering, vol. 135, no. 3, pp. 109-117,
March 2009.
Davis, Allen P., M. Shokouhian, H. Sharma, C. Minami, D. Winogradoff. 2003. Water Quality
Improvement Through Bioretention: Lead, Copper, and Zinc Removal, Water Environment
Research, 75, 73-82, January/February 2003.
Davis, Allen P., M. Shokouhian, H. Sharma, C. Minami.. 2006. Water Quality Improvement through
Bioretention Media: Nitrogen and Phosphorus Removal, Water Environment Research, vol. 78, no.
3, pp. 284-293, March 2006.
DiBliasi, C., Houng Li, Allen P. Davis, Upal Ghosh. 2009. Removal and Fate of Polycyclic Aromatic
Hydrocarbon Pollutants in an Urban Stormwater Bioretention Facility, Environmental Science and
Technology, 43, 494-502.
Chapter 3. Urban and Suburban 3-243
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
Dietz, M.E., and J. C. Clausen. 2005. A Field Evaluation of Rain Garden Flow and Pollutant Treatment,
Water, Air, and Soil Pollution, vol. 167, pp.123-138.
Dietz, M.E. 2007. Low-Impact Development Practices: A Review of Current Research and
Recommendations for Future Directions, Water, Air, Soil Pollution, 186; 351-363.
Hathaway, Jon M, and William Hunt. Urban Waterways: Removal of Pathogens in Stormwater, North
Carolina Cooperative Extension Urban Waterways Series, AGW-588-16W.
Hinman, Curtis, et al. 2005. Low Impact Development Technical Guidance Manual for Puget Sound,
Puget Sound Action Team, Washington State University Pierce County Extension.
Hinman, Curtis. 2007. Maintenance of Low Impact Development Facilities, Puget Sound Action Team.
Hon, G.E. et al. 2002. Sustainable Oil and Grease Removal from Stormwater Runoff Hotspots using
Bioretention, Paper for the 74th Annual Confe
Environment Association, State College, PA.
Bioretention, Paper for the 74th Annual Conference and Exhibition of the Pennsylvania Water
Hsieh, Chi-hsu, A.P. Davis, and B.A. Needleman. 2007. Nitrogen Removal from Urban Stormwater Runoff
Through Layered Bioretention Columns. Water Environment Research, 79(12), p.2404-2411.
Hsieh, Chi-hsu, and Allen P. Davis. 2005. Evaluation and Optimization of Bioretention Media for
Treatment of Urban Storm Water Runoff, Journal of Environmental Engineering, vol. 131, no. 11,
pp 1521-1531, November 2005.
Hunt, William F., and Nancy White. 2001. Designing Rain Gardens (Bioretention Areas), North Carolina
State University, North Carolina Cooperative Extension, available at:
www.engr.uga.edu/service/outreach/Stormwater%20BMP/BioretentionOverview.pdf, (accessed
August 2007).
Hunt, William F., A. R. Jarrett, J. T. Smith, and L. J. Sharkey. 2006. Evaluating Bioretention Hydrology
and Nutrient Removal at Three Field Sites in North Carolina, Journal of Irrigation and Drainage
Engineering, pp. 600-608, November/December 2006.
Geosyntec Consultants (Quigley, Strecker), Robert Pitt, Shohreh Karimipour. 2009. New York State
Stormwater Design Management Design Manual, Chapter 10 Enhanced Phosphorus Removal
Standards, December 2009 Draft.
Geosyntec Consultants (Quigley, M, and Clary J., et. al). 2009. Urban Stormwater BMP Performance
Monitoring, International Stormwater BMP Database, WERF/ASCE/EPA and Partners.
www.bmpdatabase.org
Li, Houng and A.P. Davis. 2009. Water Quality Improvement through Reductions of Pollutant Loads Using
Bioretention, Journal of Environmental Engineering, vol. 135, no. 8, pp. 567-576, August 2009.
3-244 Chapter 3. Urban and Suburban
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
Li, Houng, L.J. Sharkey, W.F. Hunt, and A.P. Davis. 2009. Mitigation of Impervious Surface Hydrology
Using Bioretention in North Carolina and Maryland, Journal of Hydrologic Engineering, vol. 14, no.
4, pp. 407-415.
Roseen, R.M., T.P Ballestero, J.J. Houle, P. Avellaneda, J. Briggs, G. Fowler, and R. Wildey. 2009.
Seasonal Performance Variations for Storm-Water Management Systems in Cold Climate
Conditions ASCE Journal of Environmental Engineering, 135(3): 128-137.
Simpson, Tom W., and S.E. Weammert. 2008. Infiltration and Filtration Practices: Definition and Nutrient
and Sediment Reduction Effectiveness Estimates, The Mid-Atlantic Water Program at the
University of Maryland.
http://archive.chesapeakebay.net/pubs/bmp/lnfiltration and Filtration Practices.pdf
Sun, X., and A. P. Davis. 2007. Heavy Metal Fates in Laboratory Bioretention Systems, Chemosphere,
vol.66, pp. 1601-1609.
Tackett, Tracey, Bioretention Soil Specifications, available at:
http://depts.washington.edu/urbhort/html/education/BioretentionSoilSpecs.pdf, (accessed January
2010).
University of New Hampshire. 2006. Low Impact Stormwater Management Project at the University of
New Hampshire: A Final Report to the New Hampshire Estuaries Project.
U.S. Department of Agriculture and Center for Watershed Protection. 2006. Urban Watershed Forestry
Manual, Part 2, Conserving and Planting Trees at Development Sites.
U.S. Environmental Protection Agency - Region 1. 2008. Stormwater Best Management Practices (BMP)
Performance Analysis. http://www.epa.gov/region1/npdes/stormwater/assets/pdfs/BMP-
Performance-Analysis-Report.pdf
U.S. Environmental Protection Agency. 1999. Stormwater Technology Fact Sheet: Bioretention, EPA 832-
F-99-012, Office of Water, Washington, D.C.
Washington State Department of Ecology, Evaluation of Emerging Stormwater Treatment Technologies.
Water Environment Research Federation. 2007. Critical Assessment of Stormwater Treatment and
Control Selection Issues.
Water Environment Research Federation. 2009. Flow Control and Water Quality Treatment Performance
of a Residential Low Impact Development Pilot Project in Western Washington.
Water Environment Research Federation. 2006. Infiltration vs. Surface Water Discharge: Guidance for
Stormwater Managers.
Water Environment Research Federation. 2009. User's Guide to the BMP and LID Whole Life Cost
Model, Version 2.0.
Chapter 3. Urban and Suburban 3-245
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
Infiltration practices use temporary surface or underground storage to allow incoming runoff to exfiltrate
into underlying soils. By diverting runoff into the soil, infiltration practices not only reduce the volume of
runoff discharged from the site, but also help to preserve the natural water balance on a site and can
recharge groundwater and preserve baseflow. Because of that, infiltration practices are limited to areas
with porous soils (generally where measured soil permeability rates exceed one-half inch per hour) and
where the water table or bedrock are well below the bottom of the practice.
Infiltration practices can be used at three scales: micro-infiltration, small-scale infiltration, and
conventional infiltration (VA OCR 2010).
• Micro-infiltration practices (typically dry wells, French drains or paving blocks) treat runoff from
impervious areas of 250 to 2,500 sq. ft.
• Small-scale infiltration practices (typically infiltration trenches or permeable paving) treat runoff
from impervious areas of 2,500 to 20,000 sq. ft.
• Conventional infiltration practices (typically infiltration trenches or infiltration basins) treat runoff
from impervious areas of 20,000 to 100,000 sq. ft.
Infiltration practices alone are not intended to trap sediment. At locations where sediment might be
present, the practices should be designed with a sediment forebay and grass channel or filter strip, or
other appropriate pretreatment measures to prevent clogging and failure. In addition, infiltration practices
should not be used at sites with significant pollution potential (e.g., stormwater hotspots).
Hydrologic Performance
Volume Reduction
•
Peak Flow Reduction
•
Groundwater Recharge
•
Key: • High effectiveness ® Medium effectiveness OLow effectiveness
Targeted Pollutants
Sediment
•
Nitrogen
®
Phosphorus
®
Metals
®
Oil & Grease
O
Bacteria
O
Temperature
®
Key: • High effectiveness ® Medium effectiveness O Low effectiveness
3-246
Chapter 3. Urban and Suburban
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
Photos and Diagrams
Source: Atlanta Regional Commission 2001
Figure 3A1-12.
Copped
Observation
Well
Source: Atlanta Regional Commission 2001
Figure 3A1-13.
Common Feasibility Constraints and Limitations
• Infiltration practices have a high runoff reduction capability and are suitable for use in residential
and other urban areas where measured soil permeability rates exceed 0.5 inch per hour (VADCR
2010).
Chapter 3. Urban and Suburban
3-247
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
• Infiltration practices provide minimal benefits in terms of reducing concentrations of pollutants
such as nitrate because they are below the root zone and surface soil profile.
• Total nitrogen (TN) removal is low for many infiltration and filtration practices, with the proportion
of nitrate removal extremely low. Designers are using these practices to move water, not remove
nutrients. Infiltration trenches can introduce dissolved pollutants such as nitrates and dissolved
metals into groundwater (Lucas 2005).
• Infiltration is not recommended at sites designated as stormwater hotspots to prevent possible
groundwater contamination. VADCR Design Specification No. 8 (VADCR 2010) provides a table
of Potential Stormwater Hotspot and Site Design Responses.
• Excess sediments easily clog infiltration trenches. Hence, infiltration practices should be applied
only in situations where pretreatment is provided.
• Sites that have been previously graded or disturbed do not retain their original soil permeability
due to compaction; therefore, infiltration practices should not be situated above fill soils.
• Infiltration practices should be designed to minimize potential to create conditions favorable to
mosquito breeding, which can occur if they clog and have standing water for extended periods.
• Designers should investigate whether a proposed infiltration practice is subject to a state or local
groundwater injection permit.
Volume reduction. The amount of volume reduction achieved for infiltration practices can vary based on
the size of the infiltration practice and the soil infiltration rate. VADCR (2010) estimates an annual volume
reduction from 50 percent (fora typical infiltration practice in soils with an infiltration rate of one-half to 1
inch/hour) to 90 percent (for an enhanced infiltration practice that is sized 10 percent larger than typical,
with additional pretreatment and soils with an infiltration rate of 1.0 to 4.0 inches/hour). This annual
volume reduction rate is a function of design and can be increased by modifying the design parameters.
Pitt et al. (2002) also found significant runoff reductions for infiltration practices. For example, sites
employing rain gardens (1 inch/hour amended soils, 60 sq. ft. per house) achieved annual roof runoff
volume reductions of 87 to 100 percent.
Simpson and Weammert (2009) conservatively estimated the volume reduction of infiltration practices to
be approximately 80 percent on an annual for the design criteria typically in use at the in Chesapeake
Bay region at the time.
Po I Iff t ti on
Infiltration practices with appropriate pretreatment have been estimated to be able to remove 95 percent
of the annual total suspended solids (TSS) load in typical urban post-development runoff when sized,
designed, constructed, and maintained appropriately. Undersized or poorly designed infiltration practices
can reduce TSS removal performance. Pollutant reduction is a function of the volume removal achieved.
A summary of pollutant reduction estimates for infiltration practices in the Chesapeake Bay area is
provided in Table 3A1-1.
3-248 Chapter 3. Urban and Suburban
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
Several design considerations influence the overall performance of infiltration practices, including
• Areas of Hydrologic Soil Group A or B soils shown on NRCS soil surveys should be considered
as primary locations for infiltration practices.
• The contributing drainage area to an individual infiltration practice should be less than 2 acres.
• Infiltration practices should not be hydraulically connected to structure foundations or pavement
to avoid harmful seepage. Setbacks to structures and roads vary according to the scale of
infiltration. Example specifications (VADCR 2010) state that, at a minimum, and subject to local
requirements, conventional and small-scale infiltration practices should be a minimum horizontal
distance of 100 feet from any water supply well, 50 feet from septic systems, and at least 5 feet
down-gradient from dry or wet utility lines. (VADCR 2010)
Brown and Hunt (2009) have identified innovative construction methods that can reduce soil compaction
and enhance exfiltration from bioretention cells and permeable pavement. Those construction methods
include using a rake method for excavating the bottom of the practice, avoiding excavation during or
immediately after a rainfall event, and using boreholes, ripping or trenches to increase exfiltration rates.
Maintenance is critical to the success of infiltration practices. The most common maintenance problem is
clogging of the stone by organic matter and sediment. The following considerations can minimize the risk
of clogging:
• Small-scale and conventional infiltration practices should have an observation port installed at the
low point. The observation ports should be inspected regularly and after major storms. A log
should be kept of the water level remaining to track changes in the infiltration rate.
• In general, avoid use of geotextile liners because they can be prone to clogging.
• Sediment removal should take place when the basin is thoroughly dry.
• All use of fertilizers, mechanical treatments, pesticides, and other means to assure optimum
vegetation health should not compromise the intended purpose of the infiltration basin. All
vegetation deficiencies should be addressed without the use of fertilizers and pesticides
whenever possible.
• All vegetated areas should be inspected at least annually for unwanted growth, which should be
removed with minimum disruption to the remaining vegetation and basin subsoil.
All structural components should be inspected for cracking, subsidence, spalling, erosion, and
deterioration at least annually.
Detailed maintenance considerations are in the New Jersey Stormwater Best Management Practices
Manual http://www.state.ni.us/dep/stormwater/bmp manual2.htm) and VADCR Design Specification No.
8 (http://www.chesapeakestormwater.net/all-things-stormwater/infiltration-specification.html).
Chapter 3. Urban and Suburban 3-249
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
Infiltration trenches are somewhat expensive, when compared to other stormwater practices, in terms of
cost per area treated. Typical construction costs, including contingency and design costs, are about $5
per ft3 of stormwater treated (SWRPC 1991; Brown and Schueler 1997).
Infiltration trenches typically consume about 2 to 3 percent of the site draining to them, which is relatively
small. In addition, infiltration trenches can fit into thin, linear areas. Thus, they can generally fit into
relatively unusable portions of a site.
Infiltration basins are relatively cost-effective practices because little infrastructure is needed when
constructing them. One study estimated the total construction cost at about $2 per ft3 (adjusted for
inflation) of storage fora 0.25-acre basin (SWRPC 1991). Infiltration basins typically consume about 2 to
3 percent of the site draining to them, which is relatively small. Maintenance costs are estimated at 5 to
10 percent of construction costs.
Costs reported for infiltration practices in a 189-acre watershed included costs for infiltration trenches,
and infiltration vault, raingardens, and a regional pond (CRWD 2010). The project included eight
infiltration trenches, serving 16 acres of drainage area with a total storage volume of 19,354 ft3. Averaged
costs reported were $7.69/ft3 for design and construction, not including bond interest; the construction
cost component was $6.41/ft3.
Atlanta Regional Commission. 2001. Georgia Stormwater Management Manual Volume 2: Technical
Handbook. 1st ed. August 2001. . Accessed April 19, 2010
Brown, R. A., and Hunt, W. F. 2009. Improving Exfiltration from BMPs: Research and Recommendations.
North Carolina State University, Cooperative Extension Service, Raleigh, NC. (AG-588-17W)
. Accessed
April 19, 2010.
Brown, W., and T. Schueler. 1997. The Economics of Stormwater BMPs in the Mid-Atlantic Region.
Prepared for the Chesapeake Research Consortium, Edgewater, MD, by the Center for Watershed
Protection, Ellicott City, MD.
CWP (Center for Watershed Protection). 2007. Urban Stormwater Retrofit Practices. Manual 3 in the Urban
Subwatershed Restoration Manual Series. Center for Watershed Protection, Ellicott City, MD.
CWP (Center for Watershed Protection). 2008. Technical Memorandum: The Runoff Reduction Method.
Center for Watershed Protection, Ellicott City, MD.
CRWD (Capitol Region Watershed District). 2010. Stormwater BMP Performance Assessment and Cost-
Benefit Analysis. . Accessed January 22, 2010.
3-250 Chapter 3. Urban and Suburban
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
Lucas, W. 2005. Green Technology: The Delaware Urban Runoff Management Approach. Prepared for
Delaware Department of Natural Resources And Environmental Control (DNREC) Division of Soil
And Water Conservation.
. Accessed April 19, 2010.
New Jersey Department of Environmental Management. 2004. New Jersey Stormwater Best
Management Practices Manual.
.
Accessed May 5, 2010.
Pitt, R., S-E. Chen, and S. Clark. 2002. Compacted Urban Soils Effects on Infiltration and Bioretention
Stormwater Control Designs. In Conference Proceedings- 9th International Conference on Urban
Drainage.
Simpson, T., and S. Weammert. 2009. University of Maryland/Mid-Atlantic Water Program Developing
Nitrogen, Phosphorus and Sediment Reduction Efficiencies for Tributary Strategies.
SWRPC (Southeastern Wisconsin Regional Planning Commission). 1991. Costs of Urban Nonpoint
Source Water Pollution Control Measures. Southeastern Wisconsin Regional Planning
Commission, Waukesha, Wl.
VADCR (Virginia Department of Conservation and Recreation). 2009. VA DCR Stormwater Design
Specification No. 8. Infiltration Practices Version 1.7.
.
Accessed April 19, 2010.
Chapter 3. Urban and Suburban 3-251
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
Soil restoration techniques can be used to improve compacted soils. The addition of compost can
increase soil organic content, provide beneficial bacteria and fungi, and improve or restore soil water
retention capacity and overall soil permeability. The addition of soil amendments can delay and often
reduce the peak stormwater run-off flow rate and volume, and decrease irrigation water requirements.
Amending soils will also reduce fertilizer and pesticide requirements. Soil restoration techniques can also
be used as part of a system to provide additional retention or infiltration capacity to manage runoff from
disconnected gutters, grass channels, filter strips, and impervious areas.
Compost amended soils are suitable for any pervious area where soils have been or will be compacted
by the grading and construction process. Compost amendments can be applied to the entire pervious
area of a development or be targeted in select areas of the site to enhance the performance of runoff
reduction practices. Some common design applications include
• Reduce runoff from compacted lawns and bare soils
• Increase volume of runoff infiltrated from rooftops or other areas
• Increase volume of runoff infiltrated within a grass channel or filter strip
• Increase volume of runoff reduced by a tree cluster or reforested area of the site (VADCR 2009)
The primary water quality improvements which result from restoring soil through tillage and compost
amendments are increased infiltration and the resulting reduction in runoff volumes. Reducing runoff
volume with compost generally reduces pollutant transport and loading off site (Faucette et al. 2005,
2007).
3-252
Chapter 3. Urban and Suburban
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
Photos and Diagrams
Source: VADCR Specification No. 4
Figure 3A1-14. Soil amendments.
Common Feasibility Constraints and Limitations
Compost amendments are not recommended where
• Existing soils have high infiltration rates (e.g., HSG A and B soils), although compost
amendments might be needed at mass-graded B soils to maintain runoff reduction rates
• The water table or bedrock is within 1.5 feet of the soil surface
• Slopes exceed 10 percent, unless surface applied as a compost blanket
• Existing soils are saturated or seasonally wet
• The use of tillage with soil amendments would harm roots of existing trees (stay outside the tree
drip line)
• The downhill slope runs toward an existing or proposed building foundation
• The contributing impervious surface area exceeds the surface area of the amended soils
(VADCR 2009)
Selecting the compost amendments should occur on the basis of the water quality objectives of the
jurisdiction or the project. Compost amendments should be formulated to not adversely affect water
quality. Properties such as nutrient content, soil moisture holding capacity, metals uptake capacity,
shrink/swell, product maturity, pathogen, residual chemical content and weed seed content require a high
level of scrutiny to insure the appropriate amendments are being used (Lenhart 2007).
Chapter 3. Urban and Suburban
3-253
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
Balousek conducted research that demonstrated that compost-amended, chisel-plowed, and deep-tilled
plot treatments showed runoff reductions from 74 to 91 percent, compared to the control. Chisel-plowed
and deep-tilled treatment showed cumulative runoff reductions of 40 to 53 percent, compared to the
control (Balousek 2003). The runoff reduction volume achieved by soil restoration depends on the site
application and the pre-construction hydrologicsoil group (VADCR2009).
The use of compost amendments can reduce or eliminate the need for supplemental fertilization from
inorganic fertilizer sources. Some studies, however, show that the concentrations of many pollutants can
increase in the surface runoff after soils are amended with compost, hence the need for specification
standards where nutrient runoff is to be limited. A study conducted by the USEPA ORD (Pitt et al. 1999)
found that surface runoff from the compost-amended soils had greater concentrations of almost all
constituents, compared to the surface runoff from the control sites. The concentration increases in the
surface runoff and subsurface flows from the compost-amended soil test site were quite large, typically in
the range of 5 to 10 times greater. Subsurface flow concentration increases for the compost-amended soil
test sites were also common and about as large. When the decreased surface flow quantities were
considered in conjunction with the increased surface runoff concentrations, it was found that all of the
surface runoff mass discharges were reduced by large amounts (to 2 to 50 percent of the unamended
discharges). The large phosphorus and nitrogen compound concentrations found in surface runoff and
subsurface flows at the compost-amended soil sites decreased significantly during the time of the tests
(about 6 months). The older test sites also had lower nutrient concentrations than the new sites, but still
had elevated concentrations when compared to the soil-only test plots.
Use of compost and soil amendments with quality control specifications will help avoid potential issues
such as excess nutrient runoff. Use of compost amended soils can result in an overall nutrient loading
increase, at least initially, so the trade-off between volume reduction enhancement and potential nutrient
concentration increase should be considered.
The quality of compost being used (i.e. feed stock, maturity, presence of pesticides and herbicides) must
be considered to minimize the adverse effects of water quality. One recent study concluded that due to its
high nutrient content, but low leaching properties, mature compost made from deciduous leaves makes
suitable compost for soil amendment in applications for water quality (Lenhart 2007). Two studies
conducted at the University of Georgia found that when quality compost was used and compared to
conventional seeding and mulching applications, runoff nitrogen loading was reduced by 58-92 percent
and runoff phosphorus loading was reduced by 83-97 percent (Faucette et al. 2005, 2007).
The depth of compost amendment is based on the relationship between the surface area of the
soil amendment to the contributing area of impervious cover that it receives. VADCR Stormwater
Design Specification No. 4 (www.chesapeakestormwater.net/storaqe/first-draft-baywide-desiqn-
specificationsi/BAYWIDE%20No%204%20SOIL%20AMENDMENT%20SPECIFICATION.pdf)
includes a table (Table 3) which provides guidance as to the depth of compost, incorporation
depth, and incorporation type based on the area to be amended and the contributing impervious
area.
3-254 Chapter 3. Urban and Suburban
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
• EPA's Compost Blanket Factsheet includes guidelines and specifications for compost blankets for
construction and post-construction use.
(http://cfpub.epa.gov/npdes/stormwater/menuofbmps/index.cfm?action=factsheet results&view=s
pecific&bmp=118.
• The compost material should be well composted, free of viable weed seeds, and stable with
regard to oxygen consumption and carbon dioxide generation. The compost should have a
moisture content that has no visible free water or dust produced when handling the material.
VADCR Stormwater Design Specification No. 4 (www.chesapeakestormwater.net/storage/
first-draft-baywide-design-specificationsi/BAYWIDE%20No%204%20SOIL%20
AMENDMENT%20SPECIFICATION.pdf) and the Low Impact Development Center
(www.lowimpactdevelopment.org/epa03/saspec print.htm) provide technical specifications for the
compost material.
• Soil tests should be conducted during two stages of the compost amendment process. The first
testing is done to ascertain pre-construction soil properties at proposed amendment areas. The
second soil analysis is taken to determine whether any further nutritional requirements, pH, and
organic matter adjustments are necessary for plant growth.
• VADCR Stormwater Design Specification No. 4 (www .chesapeakesto rmwate r. n et/sto rag e/
first-draft-baywide-design-specificationsi/BAYWIDE%20No%204%20SOIL%20
AMENDMENT%20SPECIFICATION.pdf) includes design criteria for soil amendments used to
enhance downspout disconnections, grass channels, vegetated filter strips, in addition to several
Bay-specific regional design variations.
• The City of Redmond, Washington Guidelines for Landscaping with Compost-Amended Soils
(www.redmond.gov/insidecitvhall/publicworks/environment/pdfs/compostamendedsoils.pdf)
(Chollak and Rosenfeld 1998) provides design specifications and cost-benefit analysis of using
compost-amended soils.
• The Composting Council and the Clean Washington Council developed guidance (Development
of a Landscape Architect Specification for Compost Utilization,
www.cwc.org/organics/org972rpt.pdf) which contains a series of short and long compost use
specifications for various landscape applications. Both product specifications and end use
instructions are provided.
VADCR recommends specific practices be used during the first year after amendment to help ensure
success where turf is the appropriate groundcover. Establishing other landscape cover types, such as
forest cover or native plantings, could require fewer or no follow-up chemical inputs after the site has
been stabilized. VADCR recommendations for turf are
• Initial inspections: For the first 6 months following amendments, the site should be inspected at
least once after each storm event that exceeds one-half inch.
• Spot Reseeding: Inspectors should look for bare or eroding areas in the contributing drainage
area or around the soil restoration area, and make sure they are immediately stabilized with grass
cover.
Chapter 3. Urban and Suburban 3-255
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
• Fertilization: Depending on the amended soils test, a one-time, spot fertilization might be needed
in the fall after the first growing season to increase plant vigor.
• Watering: Water once every 3 days for first month, and then weekly during first year (Apr-Oct),
depending on rainfall. (VADCR)
Item
Soil and site preparation
Mechanical grading and tilling
Soil amendments
Blower application
Unit
S.Y.
S.Y.
C.Y.
S.Y.
Estimated unit cost (2005 Dollars)
$5- $8
$1 8 - $27
$15 -$30
$0.45 -$1.00
Costs include the amendment and the application into the existing soil. Typical costs are provided below
(http://www.lowimpactdevelopment.org/ffxcty/5-1 soilamendments draft.pdf).
Item
Soil and site preparation
Mechanical grading and tilling
Soil amendments
Blower application
Unit
S.Y.
S.Y.
C.Y.
S.Y.
Estimated unit cost (2005 Dollars)
$5- $8
$18 -$27
$15 -$30
$0.45 -$1.00
Cost calculations based on amending soils on % acre area to manage runoff for a 1/4 acre area were
prepared by the Low Impact Development Center for Fairfax County, Virginia, in 2005, as follows:
Item
Installation
Aerate
Re-amend
Total cost
Annualized
Cost
Required cost per year (2005 dollars)
0
25,000
25,000
1
2
250
250
3
4
250
250
5
6
250
250
7
8
250
250
9
10
250
250
25
25,000
25,000
$1 ,1 25/year (includes re-amending in year 25)
3-256
Chapter 3. Urban and Suburban
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
Balousek. 2003. Quantifying decreases in stormwater runoff from deep-tilling, chisel-planting and
compost amendments. Dane County Land Conservation Department. Madison, Wisconsin.
Chollak, T. and P. Rosenfeld. 1998. Guidelines for Landscaping with Compost-Amended Soils. City of
Redmond Public Works.
www.ci.redmond.wa.us/insidecitvhall/publicworks/environment/pdfs/compostamendedsoils.pdf
Clean Washington Council and Composting Council. 1997. Development of a landscape architect
specification for compost utilization. Seattle, WA and Bethesda, MD. Prepared by: E&A
Environmental Consultants, www.cwc.org/organics/org972rpt.pdf
Faucette, L. B., J. Governo, C.F. Jordan, B. G Lockaby, H. F. Carino, and R. Governo. 2007. Erosion
control and storm water guality from straw with pam, mulch, and compost blankets of varying
particle sizes. Journal of Soil and Water Conservation 62(6):404-413.
Faucette B, C. Jordan, M. Risse, M. Cabrera, D. Coleman, and L. West. 2005. Evaluation of storm water
from compost and conventional erosion control practices in construction activities. Journal of Soil
and Water Conservation 60(6):288-297.
Pitt, R. J. Lantrip and R. Harrison. 1999. Infiltration through disturbed urban soils and compost-amended
soil effects on runoff quality and quantity. Research Report EPA/600/R-00/016. U.S. Environmental
Protection Agency, Office of Research and Development, Washington, D.C.
Lenhart, J. 2007. Compost as a soil amendment for water quality treatment facilities. Proceedings 2007
LID Conference. Wilmington, NC.
Low Impact Development Center. Guideline for Soil Amendments.
www.lowimpactdevelopment.org/epa03/soilamend.htm
VADCR (VA Department of Conservation and Recreation). 2009. Draft VA DCR Stormwater Design
Specification No. 4 - Soil Compost Amendment Version 1.5. July 2, 2009.
www.chesapeakestormwater.net/storage/first-draft-baywide-design-
specificationsi/BAYWIDE%20No%204%20SOIL%20AMENDMENT%20SPECIFICATION.pdf
Chapter 3. Urban and Suburban 3-257
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
Forests are the most beneficial land use to protect the water quality of the Chesapeake Bay (USDA
Forest Service, Urban Tree Canopy Goal Setting, 2006). Reforestation is the protection, enhancement
and expansion of tree canopy in urban and suburban areas, in yards, parks, along streets, and public
places. Urban forests provide significant environmental benefits through management of urban
stormwater but also provide other benefits such as increasing property values, reducing energy costs for
cooling in the summer, buffering wind and noise, improving air quality, providing habitat for wildlife, and
beautifying the landscape. In urban areas, trees provide an important stormwater management function
by intercepting rainfall that would otherwise run off of paved surfaces and be transported into local waters
though the storm drainage system, picking up various pollutants along the way (CWP and USFS 2009).
Trees also enhance stormwater management by evapotranspiring large quantities of stormwater, while
the roots help to reduce soil compaction, enabling more infiltration of stormwater. In general, trees
stabilize soils, reduce stormwater runoff, maintain the base flow of streams and filter nutrients and
sediment (CWP 2007).
Reforestation can be achieved using many tools, such as developing an urban tree canopy (UTC) goal for
a site or community, and achieving this goal through the use of regulations, policies and/or incentives to
plant trees and help ensure continued growth (Table 3A1-8).
Table 3A1-8. Urban watershed forestry objectives, by goal
Goal
1 . Protect
2. Enhance
3. Reforest
Objective
A. Protect priority forests
B. Prevent forest loss during
development and redevelopment
C. Maintain existing forest canopy
D. Enhance forest fragments
E. Plant trees during development
and redevelopment
F. Reforest public land
G. Reforest private land
Description
Select large tracts of currently unprotected and
undeveloped forest to protect from futures
development.
Directly or indirectly reduce forest clearing during
construction
Prevent clearing and encroachment on existing
protected and unprotected forest fragments on
developed land.
Improve the structure and function of existing
protected forests.
Require on-site reforestation as a condition of
development.
Systematically reforest feasible planting sites
within public land, rights-of-way, or other priority
sites.
Encourage tree planting on feasible locations
within individual yards or property
Source: Cappiella et al. 2005. Urban Watershed Forestry Manual. Part 1: Methods for Increasing Forest Cover in a
Watershed, USDA Forest Service, Newtown Square, PA.
3-258
Chapter 3. Urban and Suburban
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
Photos and Diagrams
Source: CWP and USDA 2009
Figure 3A1-15. Urban tree canopy.
Common Feasibility Constraints and Limitations
• Developers have little incentive to leave or restore trees on development projects.
• Unless regulations or incentives are in place, property owners might not protect existing or plant
additional trees.
• Utility corridor management needs lead to tree losses and damage.
• Human safety (fire response and transportation projects) often require tree removal.
Runoff Volume and Pollutant Load Removal Estimates
On average, forests contribute approximately 1/10 of the nitrogen to the Chesapeake Bay compared to
developed lands (1.7 Ibs acre compared to 14.8 Ibs/acre). More specifically, riparian forests that buffer
streams significantly reduce the amount of excess nutrients that enter the water, sometimes by as much
as 30 to 90 percent (CBP 2007).
Forested areas have less runoff than developed areas, as indicated by the smaller runoff coefficient used
when comparing to disturbed or impervious areas (Table 3A1-9).
Chapter 3. Urban and Suburban
3-259
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
Table 3A1-9: Site cover runoff coefficients3
Soil condition
Forest Cover
Disturbed Soils/Managed Turf
Impervious Cover
Runoff coefficient
0.02-0.05bc
0.15-0.25b'd
0.95
Source: Hirschman etal. 2008
3 Derived from research by Pitt etal. 2005; Lichterand Lindsey 1994; Schueler2001a, 2001 b; Leggetal. 1996; Pitt etal.
1999; Schueler 1987; and Cappiella et al. 2005.
b Range dependent on original Hydrologic Soil Group (HSG)
c Forest - A: 0.02 B: 0.03 C: 0.04 D: 0.05
d Disturbed Soils - A: 0.15 B: 0.20 C: 0.22 D: 0.25
Research has shown that trees are the most effective at reducing the runoff from small, more frequent
storms (CWP and USDA 2009). Volume removal credit for trees has been adopted in stormwater
programs, for example Washington State Department of Ecology has acknowledged one type of tree box
structure (one that reduces soil compaction from load-bearing pavements by using a structural vault) as
functionally equivalent to a rain garden. Allowing credit for the site-specific annual evapotranspiration
should be considered, and research is being done, primarily by the U.S. Forest Service, to help make the
tools available.
There are many local, regional and site-specific practices that can be implemented to conserve existing
urban forest and increase forest restoration. Local and state governments, and federal facilities, can
develop policies operating procedures, contract specifications, or planning documents that incorporate
urban forestry. They can encourage/require practices such as stream buffers, and provide incentives for
developers and property owners to conserve or restore urban forests. The following resources will provide
more information about those options:
• Guidelines for Developing and Evaluating Tree Ordinances (International Society of Arboriculture)
- www.isa-arbor.com/publications/ordinance.aspx
• Protecting Water Resources with Higher Density Development (USEPA) -
www.epa.qov/dced/pdf/protect water higher density.pdf
• Forest Friendly Development (Alliance for the Chesapeake Bay) -
www.alliancechesbay.orq/pubs/proiects/deliverables-145-8-2005.pdf
In addition, local governments lead by example and invest in urban forestry. Federal facilities can look to
these programs for ideas on program implementation and for evidence of how trees are valued by the
community at large, both for stormwater management benefits and other amenity value. For example, the
Philadelphia (PA) Water Department Office of Watersheds (see
www.phillvriverinfo.orq/Proqrams/SubproqramMain.aspx?ld=TreeVitalize) contends that "trees are one of
the most effective, least costly methods of storing and controlling stormwater runoff." The Office of
Watersheds has already contributed to the planting of over 500 trees within the City of Philadelphia and
hopes to increase this number through its involvement with the regional TreeVitalize Program (see
www.treevitalize.net). As part of this program, Office of Watersheds will partner with the Fairmount Park
3-260 Chapter 3. Urban and Suburban
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
Commission to receive $300,000 over a 3-year period to plant up to 84 acres of forested riparian buffers
throughout Philadelphia's park system (PWD 2009).
Federal Implementation of the Chesapeake Executive Council Directive on Forest Conservation provides
specific actions to help achieve the goals of urban forest conservation and restorations.
(www.chesapeakebay.net/press ec2007forests.aspx?menuitem=20276)
• An example of local leadership in reforestation is Baltimore County's Growing Home Campaign.
Benefit information is provided, including links to American Forests Personal Climate Change
Calculator, and the National Tree Benefits calculator from Casey Trees, a local non-profit. These
tools help to educate the public on the multiple benefits of trees. The County provides financial
incentives to plant trees through a public-private partnership with local nurseries and tree retailers.
The Center for Watershed Protection (www.cwp.org') and the USDA Forest Service has developed new
designs forstormwater management practices for use in incorporating functional tree-based stormwater
management systems into developments. These stormwater forestry practices address potential
limitations through design modifications, species selection, and other methods. The designs listed below
harness the benefits of trees to increase the effectiveness of stormwater practices, while providing other
benefits to the community, such as cooling and shade, aesthetics, and wildlife habitat (CWP and USDA
2009). The fact sheets listed below are available at www.forestsforwatersheds.org/reduce-stormwater.
• Wooded wetland
• Emergent pond/wetland system
• Bioretention and bioinfiltration facilities
• Alternating side slope plantings
• Tree check dams
• Forested filter strip
• Multi-zone filter strip
• Linear storm water tree pit
• Stormwater treatment dry ponds
Trees design in dense urban environments presents many challenges with the infrastructure of streets,
sidewalks, and utilities. Resources for addressing these issues include Reducing Infrastructure Damage
by Tree Roots: A Compendium of Strategies (Costello and Jones 2003). Other planning considerations
such as neighborhood character in tree selection and placement are essential for a successful community
street tree program (The Road to a Thoughtful Street Tree Master Plan: A Practical Guide to Systematic
Planning and Design, Simons and Johnson 2008J.
Practices to prevent root compaction and provide additional space under pavements for tree root growth
are gaining acceptance. One example is Minnesota's MARQ2 project that used an elevated-pavement
type structural support system for the planting of 179 trees along a redeveloped streetscape in the
downtown area. The system was designed to manage stormwater as one of its functions, to help prevent
combined sewer overflows
(http://www.stormh2o.com/march-april-2010/reshaping-minneapolis-proiect.aspx).
Chapter 3. Urban and Suburban 3-261
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
More information on using trees to manage stormwater are at
• Urban Watershed Forestry Manual Part 2: Conserving and Planting Trees at Development Sites
www.forestsforwatersheds.org/storage/part2forestrymanual.pdf
• Stormwater Management: Using Trees and Structural Soils to Improve Water Quality -
www .cnr.vt.edu/urbanfo restrv/sto rmwate r
• Watershed Forestry Resource Guide—Reducing Stormwater Runoff -
www.forestsforwatersheds.org/reduce-stormwater
The benefits of urban trees can be extended with appropriate selection, planting design, and
maintenance. American Forests estimates that the average life expectancy of a downtown urban street
tree is just 13 years, while their rural counterparts can live up to 100 years or more. Symptoms of tree
decline from urban stressors can take years to appear. Common causes of urban tree mortality include
the following:
• Damage to roots or soils from nearby construction activities
• Air pollution
• Physical damage from lawnmowers, vehicles or vandals
• Damage from disease and insects
• Trees planted in too small a space
• Improper planting and pruning techniques
• Tree stakes or grates left on too long
• Poor, compacted soils
• Lack of watering
• Removal or damage during maintenance of nearby utilities or sidewalks
• Competition from invasive plant species (CWP and USDA 2009)
The Urban Watershed Forestry Manual Part 3: Urban Tree Planting Guide (CWP 2006) (available at
www.forestsforwatersheds.org/storage/Part3ForestryManual.pdf) provides detailed guidance on urban
tree planting, including site assessment, planting design, site preparation, and planting and maintenance
techniques.
The costs of reforestation will vary greatly by how and where the trees are incorporated into the
urban/suburban landscape. A recent source of information on program cost includes the American Public
Works Association urban forestry handbook. This project was supported by the USDA Forest Service
Urban and Community Forestry Program on the recommendation of the National Urban and Community
3-262 Chapter 3. Urban and Suburban
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
Forestry Advisory Council. The handbook series is titled Urban Forestry Best Management Practices for
Public Works Managers, and the individual handbooks are the following:
• Volume 1 Budgeting and Funding
• Volume 2 Staffing
• Volume 3 Ordinances, Regulations, & Public Policies
• Volume 4 Urban Forest Management Plan
The series is available free for download at APWA Press,
www.apwa.net/About/CoopAgreements/urbanforestrv.
The value of the economic benefits of planting trees will also vary, however, and research is being done
to attempt to quantify the value of urban tree canopy. American Forests (www.americanforests.org') has
developed a tool to calculate the value of urban tree canopy in metropolitan areas, called CITYGreen. For
example, American Forests determined that 34 percent of Montgomery, Alabama was covered by tree
canopy in 2002. The stormwater retention capacity of Montgomery's urban forest is 227 million ft3. The
cost to manage this volume of runoff in traditional infrastructure is estimated at $454 million. In addition,
Montgomery's urban forest is estimated to remove 3.2 million Ibs of pollutants from the air annually and
this benefit is valued at $7.9 million (American Forests 2004). Even in arid locations, trees are important.
In 2007 American Forests found that Albuquerque, New Mexico's tree canopy provided 20 million cubic
feet in stormwater detention services, valued at $123 million (American Forests 2009).
Further, forests filter pollutants from runoff, therefore, allowing fewer contaminants to reach potable water
sources. This results in less treatment costs for local governments.
An example of this is in a 2002 study by the Trust for Public Land and the American Water Works
Association. For every 10 percent increase in forest cover in the source watersheds evaluated in the
survey, treatment costs decreased by approximately 20 percent, up to about 60 percent forest cover (see
Figure 3A1-16). No conclusion could be made for watersheds with more than 60 percent cover because
of a lack of data. Treatment costs can level off when forest cover is between 70 and 100 percent, the
study estimated. Other factors affecting treatment costs included the treatment practices used, the size of
the facility, and the land use characteristics, including use of BMPs (Watershed Forestry Guide, Center
for Watershed Protection and U.S. Forest Service.
(www.forestsforwatersheds.org/forests-and-drinking-water/).
The USDA Forest Service provides a Guide for Chesapeake Bay Communities (see
www.imorgangrove.net/Morgan/UTC-FOS files/UTC Guide Final DRAFT.pdf) to assist them with the
setting and evaluation of urban tree canopy goals. Setting tree canopy goals is essential to achieving
program success. Principles of an effective urban forest program and several case studies across the
United States are provided in the US Forest Service-supported guide Planning the Urban Forest:
Ecology, Economy, and Community Development (Schwab, American Planning Association 2009).
Chapter 3. Urban and Suburban 3-263
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
CO
z
O
OH
LLJ
CL
CO
O
O
• data used in regression analysis
o outlying data points not used
o
y=0.0174x2-2.7531 x+ 140.77
R2=0.5518
PERCENT OF WATERSHED FORESTED
Source: www.forestsforwatersheds.org/forests-and-drinkinq-water/
Figure 3A1-16. Relationship between forest cover and water treatment costs.
Practice/program evaluation
References
American Forests. 2009. Urban Ecosystem Analysis Albuquerque, New Mexico: Calculating the Value of
Nature. www.americanforests.orq/downloads/rea/Alb 5%2022.pdf
American Forests. 2004. Urban Ecosystem Analysis Montgomery, Alabama: Calculating the Value of the
Urban Forest. www.americanforests.org/downloads/rea/AF Montgomery.pdf
Baltimore County, Maryland, Growing Home Campaign,
www.baltimorecountvmd.gov/Agencies/environment/growinghome/index.html
Cappiella, K., T. Schueler, and T. Wright. 2005. Urban Watershed Forestry Manual. Part 1: Methods for
Increasing Forest Cover in a Watershed. USDA Forest Service, Newtown Square, PA.
Cappiella, K., T. Schueler, and T. Wright. 2005. Urban Watershed Forestry Manual. Part 2: Conserving
and Planting Trees at Development Sites. USDA Forest Service, Newtown Square, PA.
CWP (Center for Watershed Protection) and USDA (U.S. Department of Agriculture) U.S. Forest Service.
2009. Web page, . Accessed December 17, 2009
3-264
Chapter 3. Urban and Suburban
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
Chesapeake Bay Program. 2007. Chesapeake Bay Program Announces Forest Conservation Goals for
Watershed. Press Release. December 5, 2007.
www.chesapeakebay.net/press ec2007forests.aspx
Costello, L.R., and K.S. Jones, Reducing Infrastructure Damage by Tree Roots: A Compendium of
Strategies, University of California Cooperative Extension, Published by the Western Chapter of the
International Society of Arborculture.
Ernst, C., R. Gullick, and K. Nixon. 2004. Protecting the Source: Conserving Forests to Protect Water.
OpFlow. American Waterworks Association. Vol. 30, No. 5.
Forests for Watersheds, www.forestsforwatersheds.org
Hirschman, D., K. Collins, and T. Schueler. 2008. Technical Memorandum:
The Runoff Reduction Method. Center for Watershed Protection.
Legg, A. R. Bannerman and J. Panuska. 1996. Variation in the relation of runoff from residential lawns in
Madison, Wisconsin. USGS Water Resources Investigations Report 96-4194.
Lichter J., and P. Lindsey. 1994. Soil compaction and site construction: assessment and case studies.
The Landscape Below Ground. International Society of Arborculture
Pitt, R., S. Chen, S. Clark, and J. Lantrip. 2005. Soil structure effects associated with urbanization and the
benefits of soil amendments. World Water and Environmental Resources Congress. Conference
Proceedings. American Society of Civil Engineers. Anchorage, AK.
Pitt, R., J. Lantrip, and R. Harrison. 1999. Infiltration through disturbed urban soils and compost-amended
soil effects on runoff quality and quantity. Research Report EPA/600/R-00/016. Office of Research
and Development. U.S. EPA. Washington, D.C.
Philadelphia Water Department. 2009. TreeVitalize - Comprehensive Tree Planting Program.
www.phillvriverinfo.org/Programs/SubprogramMain.aspx?ld=TreeVitalize Accessed December 18,
2009.
Schueler, T. 1987. Controlling urban runoff: a practical manual for planning and designing urban best
management practices. Metropolitan Washington Council of Governments. Washington, DC.
Schueler, T. 2001 a. The compaction of urban soils. Watershed Protection Techniques
3(2):661-665.
Schueler, T. 2001 b. Can urban soil compaction be reversed? Watershed Protection Techniques
3(2):666-669.
Schwab, James C., ed. 2009. Planning the Urban Forest: Ecology, Economy, and Community
Development. American Planning Association, Planning Advisory Service, Report Number 555.
Chapter 3. Urban and Suburban 3-265
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
Simons, K., and G.R. Johnson. 2008. The Road to a Thoughtful Street Tree Master Plan: A Practical
Guide to Systematic Planning and Design, University of Minnesota.
Stormwater Magazine, Editorial Project Profile, Reshaping Downtown Minneapolis. Stormwater
Magazine, March-April, 2010.
http://www.stormh2o.com/march-april-2010/reshaping-minneapolis-proiect.aspx
USDA (U.S. Department of Agriculture). 2002. Fact Sheet #4: Control Stormwater Runoff with Trees.
Center for Urban Forest Research, Pacific Southwest Research Station, Davis, CA.
USDA (U.S. Department of Agriculture). Urban Tree Canopy Goal Setting—A Guide for the Chesapeake
Bay, Forest Service, Northeastern Area, State and Private Forestry, Chesapeake Bay Program
Office, Annapolis, MD.
3-266 Chapter 3. Urban and Suburban
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
Street sweeping is not a GI/LID practice, and reliance this practice unfortunately requires repeating the
investment continually. However, the current design and operational practices for roadways do present a
need for street sweeping for water quality and for safety and aesthetics. This fact sheet is included to
provide new information on street sweeping practices.
Street sweeping can provide significant pollutant removal, but many municipalities use sweepers that do
not perform effectively, or that can actually cause more water quality issues (Pitt et al. 2004). Aesthetics is
main reason most municipalities use sweepers, not water quality, and for this use mechanical broom
sweepers can perform well. However, they do not provide the level of water quality benefit that can be
obtained using improved sweepers.
Streets and roads compose up to 20 percent of total impervious cover in suburban subwatersheds and up
to 40 percent in highly urban subwatersheds. Contaminated particulates or street dirt accumulates along
curbed roads between rainfall events. During intense rainfall events additional particulates can be washed
on to these paved surfaces from adjoining land areas. This wet weather wash-on has been demonstrated
to be quite important in understanding the pollutant removal benefits of street sweeping (Sutherland and
Jelen 1996). Sources of pollutants include wash-on, atmospheric deposition, vehicle emissions, cargo
spills, and wear and tear, breakup of street surface, road salts and deicers, litter, bird droppings, grass
clippings, leaves and other organic material and sanding. This results in the accumulation of stormwater
pollutants such as sediment, nutrients, metals, hydrocarbons, bacteria, pesticides, trash and other toxic
chemicals (CWP 2008).
These pollutants typically remain on streets until they are washed into the storm drain system during a
rainfall event. However, some communities use street sweeping to remove some of these pollutants and
prevent them from being conveyed into the storm drain system (CWP 2008).
Street sweeping and vacuuming includes the use of self-propelled and walk-behind equipment to remove
sediment from streets and roadways, and to clean paved surfaces in preparation for final paving.
Sweeping and vacuuming prevents sediment from entering storm drains or receiving waters (CASQA
2003).
Targeted Pollutants
Sediment
®
Hydrocarbons
®
Trash
®
Nutrients
®
Key: • High effectiveness ® Medium effectiveness OLow effectiveness
Chapter 3. Urban and Suburban
3-267
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
Photos and Diagrams
Source: www.quincvma.qov/Livinq
Figure 3A1-17. The majority of pollutants on streets are closest to the curb.
Common Feasibility Constraints and Limitations
The following are common feasibility constraints and limitations of street sweeping:
• Sweeping and vacuuming might not be effective when sediment is wet or when tracked soil is
caked (caked soil might need to be scraped loose) (CASQA 2003).
• Be careful not to sweep up any unknown substances or any object that could be hazardous
(CASQA 2003).
• The use of kick brooms or some sweeper attachments tend to spread dirt rather than remove it
(CASQA 2003). On the other hand, gutter brooms can be very effective at capturing street dirt.
• Access to the curb is paramount to street sweeping efficiency, as the majority of pollutants on
streets are closest to the curb. Parked cars can restrict access. Compliance with an appropriately
enforced no-parking zone can provide access for street sweeping to the curb (CWP 2008).
Pollutant Load Removal Estimates
The ability of street sweepers to remove common stormwater pollutants varies depending on the sweeper
technology being used, climate factors such as rainfall patterns, sweeper operation (including sweeper
speed), sweeper maintenance (including broom wear), sweeping frequency, pavement conditions, the
number of parked cars encountered, and the chemical and physical characteristics of the pollutants that
have accumulated on the pavement. In addition, it can be difficult to estimate pollutant removal rates for
street sweepers because of the difficulty in measuring particulate matter transported in runoff (APWA
2009).
Pros and cons of sweeper type on pollutant removal performance consist of the following:
• Mechanical street sweepers are more effective at removing larger-sized particles than fine-
grained particles and nutrients. Newer high efficiency sweepers pick up much smaller particles,
as well (Sutherland and Jelen 1997; Pitt et al. 2004).
• Mechanical sweepers are typically the least expensive and are better suited to pick up trash and
coarse-grained sediment particles (CWP 2008). This provides less water quality benefits, but this
3-268 Chapter 3. Urban and Suburban
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
practice could be used as the first pass of tandem sweeping operations when followed by a
sweeper that can remove the pollutant-heavy fine-sized particles left behind by the mechanical
sweeper.
• Regenerative air and high efficiency sweepers are better at removing fine-grained sediment
particles but are less effective on wet surfaces (although can still out-perform mechanical
sweepers) and are more expensive (CWP 2008).
• Street sweeping is presumed to be more effective at reducing stormwater pollutants in arid and
semi-arid climates where pollutants can accumulate over longer intervals on street and curb
surfaces (CWP 2008).
• Because they operate as a mobile BMP on-the-go, street sweeping can be of particular value in
reducing pollutants from ultra-urban areas where few BMPs are feasible (Law et al. 2008).
• Street cleaning equipment can be most effective in areas where the surface to be cleaned is the
major source of contaminants. These areas include freeways, large commercial parking lots, and
paved storage areas (Pitt et al. 2004).
• Improving or initiating street sweeping activities can reduce the amount of stormwater pollution
that is conveyed into local aquatic resources. It requires examination of existing street sweeping
technology and operations (if any) and identification of where improvements can be made to
reduce the amount of pollution that has accumulated on public streets and roadways.
(CWP 2008).
• Develop a list of areas where street sweeping activities could have the greatest influence on
water quality. For example, an area with high accumulations of pollutants might suggest that
more regularly scheduled street sweeping is needed. Also, street sweeping can be concentrated
on the dirtiest streets in sensitive subwatersheds (CWP 2008).
• At a minimum, sweeping should occur during periods of heavy accumulation, such as early spring
removal of deicing chemicals and sand in temperate climates (CWP 2008). During the fall, leaf
removal should be conducted with specialized equipment, such as vactor trucks, as seasonal
leaves can contribute 25 percent of nutrient loading in catch basins.
• Include municipal parking lots in the sweeping schedule.
Several factors influence the overall cost of street sweeping:
• Street sweeping is major investment and operators must be specially trained on how to properly
drive and maintain them. Training should be held at least once a year for staff to provide them
with a thorough understanding of the proper implementation of sweeping and other pollution
prevention/good housekeeping practices, and safety procedures (CWP 2008).
• Costs can vary significantly by the type of sweeper, operation and maintenance expenses, and
sweeping frequency. The capital cost for a conventional street sweeper is between $60,000 and
$120,000 with newer technologies approaching $180,000 (CASQA 2003).
Chapter 3. Urban and Suburban 3-269
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
It is important to evaluate the process and measurable performance goals and implementation milestones
made for a street sweeping program (Table 3A1-10).
Table 3A1-10. Examples of measurable goals and implementation milestones for improving
municipal street sweeping activities3
Example measurable goals
Time frame
Priority
Goals related to program startup
Identify and collect basic information about municipal
street sweeping activities
Add the information about street sweeping activities to
the simple database or binder that contains basic
information about each municipal operation
Develop a digital CIS or hard copy map showing the
location of all municipal street sweeping activities
Prioritize local pollution prevention/good housekeeping
efforts
Complete shortly after
program startup; updated
regularly after that
Year 1 , repeat every 5
years
Essential
Essential
Optional but
recommended
Essential
Goals related to preventing or reducing stormwater pollution
Collect additional information about the way that street
sweeping activities are conducted within your
community. Include sweeper type; efficiency of fine
sediment fraction removed, sweeping frequency, miles
swept/coverage, and parking policies and enforcement
along sweeping routes.
Prescribe pollution prevention/good housekeeping
practices to improve the way that municipal street
sweeping activities are conducted within your
community
Develop implementation plan for prescribed street
sweeping program
Secure funding and resources to implement prescribed
street sweeping program
Implement prescribed street sweeping program
YeaM
Begin in Year 1
Begin in Year 2
Essential
Essential
Essential
Essential
Essential
Goals related to program evaluation
Develop measurable performance goals and
implementation milestones
Evaluate progress in meeting measurable goals and
implementation milestones, including pollution
prevent/good housekeeping practices
Complete shortly after
program startup; updated
regularly after that
Essential
Essential
Source: adapted from CWP 2008
a. These goals assume that street sweeping is at the top of your prioritized municipal operations list.
3-270
Chapter 3. Urban and Suburban
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
The methods used to evaluate success in meeting measurable goals and implementation milestones can
be as simple as a semi-annual or annual inspections used to identify the improvements that have been
put in place and the improvements that still need to be made (CWP 2008).
California Stormwater Quality Association (CASQA). 2003. California Stormwater BMP Handbook,
Construction. www.cabmphandbooks.com/Documents/Construction/SE-7.pdf
Center for Watershed Protection (CWP). 2008. Urban Subwatershed Restoration Manual 9: Municipal
Pollution Prevention/Good Housekeeping Practices. Verison 1. Ellicott City, MD.
www.cwp.org/Store/usrm.htmtf9
Center for Watershed Protection (CWP). 2006. Technical Memorandum 1. Literature Review. Research in
Support of an Interim Pollutants Removal Rate for Street Sweeping and Storm Drain Cleanout
Activities. Ellicott City, MD.
Neely L. Law, et al. 2008. Deriving Reliable Pollutant Removal Rates for Municipal Street Sweeping and
Storm Drain Cleanout Programs in the Chesapeake Bay Basin. Center for Watershed Protection,
Ellicott City, MD.
www.cwp.org/Resource Library/Restoration and Watershed Stewardship/municipal.htm
Sutherland, R.C., and S.L. Jelen. 1997. Contrary to Conventional Wisdom: Street Sweeping can be and
Effective BMP. In James, W. Advances in Modeling the Management of Stormwater Impacts, vol. 5.
Published by CHI, Guelph, Canada, pp 179-190.
Sutherland, R.C. 2009. Recent street sweeping pilot studies are flawed. IN: APWA Reporter, September
2009.
Pitt, R., R. Bannerman, and R. Sutherland. 2004. The Role of Street Cleaning in Stormwater
Management, Water World and Environmental Resources Conference 2004, Environmental and
Water Resources Institute of the American Society of Civil Engineers, Salt Lake City, Utah. May
27-June 1,2004.
http://rpitt.eng.ua.edu/Publications/StormwaterTreatability/Street%20Cleaning%20Pitt%20et%20al
%20SLC%202004.pdf
Chapter 3. Urban and Suburban 3-271
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
1.10 Constructed Wetlands
Description of Practice
Wetland systems are designed for flood control and removal of pollutants from stormwater. Like natural
wetlands, stormwater wetlands (a.k.a. constructed wetlands) temporarily store the water and have the
capacity to improve water quality through microbial breakdown of pollutants, plant uptake, retention of
stormwater, settling and adsorption (Barr2001). Constructed wetlands, like wet ponds, incorporate
wetland plants into the design and require relatively large contributing drainage areas. As stormwater
runoff flows through the wetland, pollutant removal is achieved through settling and biological uptake.
Constructed wetlands have zones and plants similar to wet ponds but often with less fluctuation and the
ability to maintain a higher diversity (Shaw 2003).
Wetlands are among the most effective stormwater practices in terms of pollutant removal and also offer
aesthetic and habitat value. Although natural wetlands can sometimes be used to treat stormwater runoff
that has been properly pretreated, stormwater wetlands are fundamentally different from natural wetland
systems. Constructed wetlands are designed specifically for the purpose of treating stormwater runoff,
and typically have less biodiversity than natural wetlands in terms of both plant and animal life. Several
design variations of the constructed wetland exist, each design differing in the relative amounts of shallow
and deep water, and dry storage above the wetland. Sediment forebays and micropools are often
designed as part of constructed wetlands to prevent sediment from filling the wetland (Barr2001).
A distinction should be made between using a constructed wetland for stormwater management and
diverting stormwater into a natural wetland. The latter practice is not recommended because altering the
hydrology of the existing wetland with additional stormwater can degrade the resource and result in plant
die-off and the destruction of wildlife habitat. In all circumstances, natural wetlands should be protected
from the adverse effects of development, including impacts from increased stormwater runoff. This is
especially important because natural wetlands provide stormwater and flood control benefits on a regional
scale (USEPA 2006).
Photos and Diagrams
Source: USEPA 2006
Figure 3A1-18. Stormwater wetland.
3-272
Chapter 3. Urban and Suburban
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
Source: Shaw 2003
Figure 3A1-19. Drawing of a wetland.
Source: Barr2001/Schueller 1992
Figure 3A1-20. Plan diagram of a shallow marsh constructed wetland.
Photo by A.M. Baldwin. Source: Simpson 2009
Figure 3A1-21. Stormwater wetland at the University of Maryland, College Park.
Runoff from the parking lot enters the wetland from the left, flows in a roughly U-shaped
counterclockwise pattern, and discharges via a riser at the top center of the wetland.
Chapter 3. Urban and Suburban
3-273
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
Source: VA OCR 2009
Figure 3A1-22. Photo of a constructed wetland basin.
Source: VA OCR 2009
Figure 3A1-23. Plan View Constructed Wetland Basin.
3-274
Chapter 3. Urban and Suburban
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
Wetland
Cell 1
Source: \/A OCR 2009
Figure 3A1-24. Pond/wetland combination.
Common Feasibility Constraints and Limitations
Constructed wetlands are widely applicable and can be applied in most regions of the United States;
however, there are limitations in specific climates and areas, including
• Arid and semi-arid climates where evaporation makes it difficult to retain water in a shallow pool.
• Ultra urban areas with little pervious surface available for the large land area required.
• Hot spots that have a high potential for groundwater contamination, e.g., gas station runoff or
areas where chemicals are stored or managed.
• Retrofit or new construction in areas with minimal land.
Chapter 3. Urban and Suburban
3-275
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
• Cold water trout streams because of thermal effects of heating a shallow pool, which can
discharge warmer water.
• Breeding ground for mosquitoes in improperly designed systems.
• Careful selection of plants that will sustain life over the lifetime of the project.
• Nutrient release can occur during the non-growing season.
• Consideration of impact on natural wetlands and forests.
(Adapted from USEPA 2006)
Pollutant Reduction. Considerable variations exist in both methods of reporting treatment effectiveness,
and a broad range of effectiveness is noted for individual sites. In a literature review conducted for
estimating the effectiveness of these practices in the Chesapeake Bay region, effectiveness estimates for
urban constructed wetlands were 60 percent for total suspended solids, 20 percent for total nitrogen and
45 percent for total phosphorus, and volume reduction was not noted as significant source of pollutant
removal (Simpson 2009). One study found that an experimental system had little potential for long-term,
consistent mass removal of total nitrogen and total phosphorus, depending on the concentrations in the
incoming runoff (Nietch 2005).
Results from the studies show that some bacteria removal and inactivation can occur in constructed
wetlands. The factors of light, time, and temperature, as well as other factors (e.g., predation,
sedimentation, sorption, filtration, pH, BOD, pH, and DO) can also contribute to the inactivation of
indicator bacteria in constructed wetland BMPs (USEPA 2006).
Cold weather performance. Cold winter temperatures can cause freezing of the permanent pool or
freezing at inlets and outlets. Also in the winter, high salt concentrations in runoff from road salting, as
well as high sediment loads from road sanding, can impact wetland vegetation. During the spring,
snowmelt can carry a relatively high pollutant load with the high volume of runoff.
One of the greatest challenges of stormwater wetlands, particularly shallow marshes, is that much of the
practice is very shallow. Therefore, much of the volume in the wetland can be lost as the surface of the
practice freezes. One study found that the performance of a wetland system was diminished during the
spring snowmelt because the outlet and surface of the wetland had frozen. Sediment and pollutants in
snowmelt and rainfall events skated over the surface of the wetland, depositing at the outlet of the
wetland. When the ice melted, this sediment was washed away by storm events (Oberts 1994). Several
design features can help minimize this problem, including the following:
• On-line designs allowing flow to move continuously can help prevent outlets from freezing.
• Multiple cells, with a berm or weir separating each cell, can help retain storage for treatment
above the ice layer during the winter season.
• Freeze-resistant outlets (i.e., weirs or pipes with large diameters).
• Planting salt-tolerant vegetation, such as pickle weed or cord grass when wetlands drain highway
runoff, or parking lots.
3-276 Chapter 3. Urban and Suburban
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
• Using a large forebay can help to capture the sediment from road sanding.
(Adapted from USEPA 2006)
/- , ' - , - . L .
Several design considerations influence the overall performance of stormwater wetlands, including the
following:
• Sufficient drainage area to maintain water in the permanent pool, which is typically about 25
acres in humid area and more in drier regions.
• Upstream slopes of up to about 15 percent with shallow local slopes large enough to ensure
hydraulic conveyance (generally about three to five foot drop minimum from inlet to outlet).
• Minor design adjustments for regions of karst (i.e., limestone) topography to include an
impermeable liner.
• Wetlands can intersect the groundwater table, which might affect pollutant reduction capabilities.
• Incorporation of a sediment forebay, a small pool (typically about 10 percent of permanent pool
volume), to trap coarse particles.
• Surface area of the stormwater wetland should be at least 1 percent of the drainage area.
• Length-to-width ratio of at least 1.5:1 to prevent short circuiting.
• Inclusion of both very shallow (<6 inches) and moderately shallow (<18 inches) to provide a
longer flow path through the wetland and encourage plant diversity.
(Adapted from USEPA 2006)
There are three basic design variations of constructed wetlands:
• Shallow Marsh: Most of the wetland volume is in the relatively shallow high marsh or low marsh
depths with the only deep portions in the forebay at the inlet and the micropool at the outlet.
These systems are appropriate at the terminus of a storm pipe drain or open channel (usually
after upland runoff reduction).
• Pond/Wetland System: Combining the Wet Pond and shallow marsh designs requires less
surface area than the shallow marsh alone because of the relatively deep volume of the Wet
Pond. These systems are appropriate in moderately to highly urbanized areas.
• Linear Wetland Cells: Systems installed within the conveyance system or zero-order stream
channels.
(Adapted from VADCR 2009)
Chapter 3. Urban and Suburban 3-277
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
Typical maintenance activities are shown in Table 3A1-11 (USEPA 2009).
Table 3A1-11. Constructed wetland maintenance activities
Maintenance activity
- Cleaning and removing debris after major storm events (> 2" rainfall)
- Harvesting of vegetation when a 50% reduction in the original open water
surface area occurs
- Repairing embankment and side slopes
- Removing accumulated sediment from forebays or sediment storage areas
when 60% of the original volume has been lost
- Removing accumulated sediment from main cells of pond once 50% of the
original volume has been lost
Schedule
Annual or as needed
5-year cycle
20-year cycle
The construction cost of urban constructed wetlands varies depending on the design, location, site-
specific conditions, and the amount of earthwork and planting. (USEPA Wetlands Fact Sheet 1999).
Construction cost estimates and references are provided by EPA in the Menu of BMPs Stormwater
Wetland Fact Sheet:
(tittp://cfpub.epa.gov/npdes/stormwater/menuofbmps/index.cfm?action=browse&Rbutton=detail&bmp=74
&minmeasure=5).
Table 3A1-12 provides an example of costs taken from North Carolina case studies provided in (Urban
Waterways, North Carolina State University Cooperative Extension 2000,
www.neuse.ncsu.edu/SWwetlands.pdf).
Unit costs for typical wetlands maintenance items are in Appendix A of EPA's 2009 Stormwater Wet Pond
and Wetland Management Guidebook (www.epa.gov/npdes/pubs/pondmgmtguide.pdf)
Virginia Department of Conservation and Recreation Stormwater Design Specification No. 13
Constructed Wetlands, Version 1.6, September 30, 2009.
www.vwrrc.vt.edu/swc/NonProprietaryBMPs.html
3-278
Chapter 3. Urban and Suburban
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
Table 3A1-12. Sample land and construction costs of a stormwater wetland (taken from North
Carolina case studies).
Cost type
Land
Excavation
and grading
Hauling
Vegetation
Spillway and
drawdown
Description
Land values can vary from
$1 0,000 to $400,000 per acre in
North Carolina. Assume $40,000
at this site.
A total of 4,800 cubic yards
(1 acre x 1 yard depth).
Area adjacent to site used to
spread excess earth — costs
included excavation costs
Some local transplants, some
natural establishment, and a few
ornamental plants from local
nursery.
Treated lumber used for aesthetic
purposes. Drawdown holes drilled
through principal spillway.
Unit cost
$40,000/ac
$8/cy
Part of above
costs
$0.30/sf
$0.25/sf
Total Land and Construction Costs
Total cost
$40,000
$38,400
Included in
excavation and
grading costs
$13,000
$11,000
$102,400
Cost per acre of
watershed
treated
$800
$770
Included in
excavation and
grading costs
$260
$220
$2,050
Note: The table is based on a 1-acre wetland treating a 50-acre watershed.
Barr Engineering Company. 2001. Minnesota Urban Small Sites BMP Manual, Stormwater Best
Management Practices for Cold Climates. Prepared for the Metropolitan Council.
www.metrocouncil.org/environmentAA/ater/BMP/CH3 STConstWLSwWetland.pdf
Hunt, W., and B.A. Doll. 2000. Urban Waterways, Designing Stormwater Wetlands for Small Watersheds.
North Carolina State University Cooperative Extension, www.neuse.ncsu.edu/SWwetlands.pdf
Nietch, C., et al. 2005. Nutrient-based ecological consideration for stormwater management basins:
Ponds and wetlands. In Proceedings of the World Water and Environmental Congress, Anchorage,
Alaska, May 15-19, 2005.
Schueler, T.R. 1992. Design of Stormwater Wetland System: Guidelines for Creating Diverse and
Effective Stormwater Wetlands in the Mid-Atlantic Region. Metropolitan Washington Council of
Governments, Washington, DC.
Shaw, D., and R. Schmidt. 2003. Plants for Stormwater Design: Species Selection for the Upper Midwest.
Minnesota Pollution Control Agency, Saint Paul, MN.
Simpson, T., S. Weammert, and A. Baldwin. 2009. Urban Wet Ponds and Wetlands Best Management
Practice.
Chapter 3. Urban and Suburban
3-279
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
Struck, S., A. Selvakumar, and M. Borst. 2006. Performance of Stormwater Retention Ponds and
Constructed Wetlands in Reducing Microbial Concentrations. EPA/600/R-06/102.
www.epa.gov/nrmrl/pubs/600rQ6102/600r06102.pdf
USEPA (U.S. Environmental Protection Agency). 2006. NPDES Stormwater Wetland Fact Sheet:
Minimum Measure: Post-Construction Stormwater Management in New Development and
Redevelopment, Office of Wastewater Management, Washington, D.C., May 2006.
http://cfpub.epa.gov/npdes/stormwater/menuofbmps/index. cfm?action=browse&Rbutton=detail&bm
p=74&minmeasure=5
USEPA (U.S. Environmental Protection Agency). 2009. Stormwater Wet Pond and Wetland Management
Guidebook, EPA 833-B-09-001. Office of Wastewater Management, Washington, D.C., February
2009. http://www.epa.gov/npdes/pubs/pondmgmtguide.pdf
VADCR (Virginia Department of Conservation and Recreation). 2009. Draft VA DCR Stormwater Design
Specification No. 13: Constructed Wetlands Version 1.5, July 2, 2009
3-280 Chapter 3. Urban and Suburban
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
Appendix 2: Methods and Tools for Controlling
Stormwater Runoff (Quantity and Quality)
This appendix describes various methods, including guidance manuals, and tools for controlling
stormwater runoff. This appendix includes:
2.1 Methods and Manuals
2.2 Complex Models
2.3 Simpler Models (largely spreadsheet-based or online)
2.1 Methods and Manuals
Nationally Applicable LID Design Methods and Manuals
Prince George's County, Maryland, Low-Impact Development Design Strategies: An Integrated Design
Approach, EPA-841-B-00-003, 2000.
Prince George's County, Maryland, Low-Impact Development Hydrologic Analysis, EPA-841-B-00-002,
2000. www.epa.gov/nps/lid
EPA, Stormwater Best Management Practices Design Guide, Office of Research and Development,
EPA/600/R-04/121, Volumes 1-3 (121, 121 A, 121B), September 2004.
www.epa.gov/nrmrl/pubs/600r04121/600r04121.htm
Center for Watershed Protection Urban Subwatershed Restoration Manual Series
(www.cwp.org/Store/usrm.htm')
Center for Watershed Protection Managing Stormwater in Your Community: A Guide for Building an
Effective Post-Construction Program
(www.cwp.org/Resource Library/Center Docs/SW/pcguidance/Manual/PostConstructionManual.pdf)
Water Environment Research Foundation (WERF). Decentralized Stormwater Controls For Urban
Retrofit And Combined Sewer Overflow Reduction
www.werf.org/AM/Template.cfm?Section=Search&Template=/CustomSource/Research/
ResearchProfile.cfm&Reportld=03-SW-3&CFID=2715758&CFTOKEN=75805127
WERF. Critical Assessment of Stormwater Treatment and Control Selection Issues. In Publication.
Geosyntec Consultants and Wright Water Engineers. Urban Stormwater BMP Performance Monitoring.
2009. www.bmpdatabase.org/MonitoringEval.htm
The Low-Impact Development Center, www.lowimpactdevelopment.org: several LID manuals
Chapter 3. Urban and Suburban 3-281
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
Federal Facility Design Manuals
EPA Technical Guidance on Implementing the Stormwater Runoff Requirements for Federal Projects
under Section 438 of the Energy Independence and Security Act, 2009, EPA-841-B-09-001, December
2009, www.epa.gov/owow/nps/lid/section438
U.S. Naval Facilities Engineering Command, Low Impact Development, Draft, Unified Design Criteria,
UFC 3-210-10, October 2004. www.wbdg.org/ccb/DOD/UFC/ufc 3 210 10.pdf
U.S. Department of Housing and Urban Development, The Practice of Low Impact Development, 2003,
www.huduser.org/portal/publications/destech/lowlmpactDevl.html
U.S. Army Corps of Engineers. Low Impact Development for Sustainable Installations: Stormwater
Design and Planning Guidance for Development within Army Training Areas. Public Works Technical
Bulletin 200-1-62. October 2008.
Transportation-focused LID Design Methods and Manuals
Low Impact Development Center, Inc., 2006, GeoSyntech Consultants, University of Florida, Oregon
State University, Evaluation of Best Management Practices for Highway Runoff Control, Report N. 565
for National Cooperative Highway Research Program (NCHRP), Project 25-20 (1).
http://onlinepubs.trb.org/Onlinepubs/nchrp/nchrp rpt 565.pdf
Example State/Local Design Manuals and Resources
(also refer to individual practice fact sheet references)
The Chesapeake Stormwater Network. Baywide BMP Design Specifications.
www.chesapeakestormwater.net/baywide-design-specifications2
Pennsylvania. Stormwater BMP Manual. 2006.
www.elibrary.dep.state.pa.us/dsweb/View/Collection-8305
Delaware. Standards & Specifications for Green Technology BMPs. 2005.
www.dnrec.state.de.us/DNREC2000/Divisions/Soil/Stormwater/New/GT Stds%20%26%20
Specs 06-05.pdf
District of Columbia. Stormwater Guidebook.
http://ddoe.dc.gov/ddoe/frames.asp?doc=/ddoe/lib/ddoe/stormwaterdiv/2009.05.07 SWM Table of Con
tents.pdf
North Carolina Coastal Federation, www.nccoast.org, resources on implementing LID to protect shellfish
beds and coastal beaches.
U.S Fish and Wildlife Service, Bayscapes, www.fws.gov/ChesapeakeBav/Bayscapes.htm
3-282 Chapter 3. Urban and Suburban
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
BMP Performance Information
WERF. International Stormwater BMP Database, www.bmpdatabase.org
EPA. Urban BMP Performance Tool, www.epa.gov/npdes/urbanbmp
Center for Watershed Protection. National Pollutant Removal Performance Database.
www.cwp.org/Resource Library/Controlling Runoff and Discharges/sm.htm
Source Control and Pollution Prevention Manuals
EPA National Management Measures to Control Nonpoint Source Pollution from Urban Areas Office of
Oceans, Wetlands and Watersheds, EPA-841B-05-004, December 2005
(www.epa.gov/owow/nps/urbanmm/)
EPA The Use of Best Management Practices (BMPs) in Urban Watersheds, Office of Research and
Development, EPA/600/R-04/184, September 2004.
Center for Watershed Protection Urban Subwatershed Restoration Manual Series, Volume 8,Pollution
Source ControlPractices, February 2007 (www.cwp.org/Store/usrm.htm')
Managing Storm Water Runoff to Prevent Contamination of Drinking Water and Managing Highway
Deicing to Prevent Contamination of Drinking Water. Steve Ainsworth, USEPA
2.2 Complex, LID-capable Models
Publicly available models appropriate for evaluating LID practices include:
• EPA's Storm Water Management Model, version 5 (SWMM5)
• EPA's Hydrologic Simulation Program—FORTRAN model (HSPF)
• U.S. Army Corps of Engineers, Hydrologic Engineering Center - Hydrologic Modeling
System (HEC-HMS)
• Western Washington's Hydrology Model, version 3 (WWHM3)
• University of Wsconsin, Civil & Environmental Engineering Department, Water
Resources Group - RECARGA
The following summarizes these complex, LID-capable models.
EPA's Storm Water Management Model, version 5 (SWMM5)
EPA's Storm Water Management Model (SWMM) is a dynamic, rainfall-runoff simulation model
used for single event or long-term (continuous) simulation of runoff quantity and quality from
primarily urban areas. SWMM5 divides the water balance process into four compartments:
Chapter 3. Urban and Suburban 3-283
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
(1) atmosphere (precipitation); (2) land surface (divides precipitation into infiltration, storage, or
runoff; (3) groundwater; and (4) transport (pipe and channel flow, as well as storage). It can
perform both single event and long-term continuous simulation using precipitation data recorded
at hourly or less intervals. These inputs can be supplemented with monthly evaporation data
and daily temperature readings. Different hydraulic routing techniques are available to manage
from simple to complex routing conditions. Infiltration can be simulated using Morton, Green-
Ampt, or Curve Number techniques. These techniques vary in complexity and the availability of
the parameters used for their estimation. They can take into account initial soil moisture
conditions, hydraulic conductivity, soil moisture capacity, and its regeneration. Separate
accounting is provided for runoff from pervious areas and impervious areas, and routing of
runoff from one area over another is possible. SWMM5 can simulate pollutant build-up, washoff,
and treatment, although these capabilities are not needed to determine predevelopment
hydrology comparisons.
SWMMS's advantages are that it uses physically based process models and input parameters
wherever possible, it can model any number of storage- or infiltration-based BMPs, it contains
robust procedures for routing runoff flow, and it allows models to be built to any level of spatial
detail needed to provide the most accurate water balance for a site. A disadvantage is that it
does not currently have the capability to model some BMPs the employ infiltration, storage,
and/or flow routing in combination with one another (such as infiltration ponds and vegetated
swales).
This model has been in use since 1971, and has since undergone several major upgrades since
its inception, including expansion of LID applications in 2009. The following applications are
discussed in the 2009 manual:
1. Post-Development Runoff
2. Surface Drainage Hydraulics
3. Detention Pond Design
4. Low Impact Development
5. Runoff Water Quality
6. Runoff Treatment
7. Dual Drainage Systems
8. Combined Sewer Systems
9. Continuous Simulation
3-284 Chapter 3. Urban and Suburban
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
The model and supporting documentation are at
www.epa.gov/ednnrmrl/models/swmm/index.htm.
EPA's Hydrological Simulation Program Fortran (HSPF), and
WinHSPF
WinHSPF has broad capabilities for hydraulic, hydrologic, and water quality modeling. BMPs
are modeled as either reaches that can represent channels or areas of storage, or as pervious
land. WinHSPF can be used for a single rain event or continuous simulation. In WinHSPF, only
the pervious land module can be used for infiltration. Infiltration can vary with time as soil
moisture conditions change, and spatial variability in infiltration rates can be addressed. The
advantages of WinHSPF include the very broad capabilities for simulating infiltration, surface
runoff, groundwater movement, evaporation and evapotranspiration, snowmelt, and for water
quality parameters, including temperature (a requirement of Section 438). Another advantage is
that it has been incorporated into BASINS, an EPA model that takes advantage of the
capabilities of GIS and other systems.
Disadvantages of WinHSPF are its complexity and its limited routing capability compared to
SWMM5.
It is the only comprehensive model of watershed hydrology and water quality that allows the
integrated simulation of land and soil contaminant runoff processes with in-stream hydraulic and
sediment-chemical interactions. The user must input continuous rainfall records to drive the
runoff model. Additional records of evapotranspiration, temperature, and solar intensity can be
imported for more accurate results. A large number of model parameters can be specified
although default values are provided where reasonable values are available. The result of this
simulation is a time history of the runoff flow rate, sediment load, and nutrient and pesticide
concentrations, along with a time history of water quantity and quality at any point in a
watershed.
The model and supporting documentation are available for download at
www.epa.gov/ceampubl/swater/hspf.
HEC-HMS
HEC-HMS replaces HEC-1 by building on the original capability of simulating precipitation-runoff
and routing processes. HEC-HMS added capabilities for distributed modeling and continuous
simulation. HEC-HMS includes a broad selection of models for representing rainfall
distributions, computing runoff volume (i.e. different selections of infiltration and losses
Chapter 3. Urban and Suburban 3-285
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
algorithms), for modeling direct runoff (overland flow and interflow); baseflow in a stream; and
channel flow. It is capable of modeling either event-based or continuous simulations.
HEC-HMS uses three major components in analyzing a hydrologic system:
1. Basin model—user-entered data on basin data, including losses characteristics and
connectivity
2. Meteorological model—user-entered data on rainfall, snowmelt, and evapotranspiration
rate
3. Control specifications—user-entered calculation intervals
Precipitation considerations include areal and temporal distribution, and use of radar data.
Evapotranspi ration and precipitation are represented in the soil-moisture accounting (SMA)
model and enables modeling of the drying of the watershed, or otherwise movement of water,
between rainfall events for continuous modeling. A five-layer model is used: canopy, surface,
soil, upper groundwater, and lower groundwater. Alternatively, there is a deficit-constant method
that simplifies to a one-layer model for soil. HEC-HMS divides surfaces into either directly
connected impervious areas or pervious surfaces. Losses on the pervious surfaces include
interception, infiltration, storage (consisting of canopy, surface, soil-profile, and groundwater),
evaporation and transpiration.
HEC-HMS is widely used for simulating distributed infiltration controls, particularly when
interactions with streams (with potentially varying baseflows or flash-flows) or input into
subsequent river analysis is desired, via HEC-RAS. HEC-HMS also includes extensive
elements for modeling engineered structures in management systems for reservoirs, dams,
pumps, and other structures.
This model is available for download at
www.hec.usace.army.mil/publications/pub download.html
WWHM3
WWHM3 is the third edition of the Western Washington Hydrology model developed for
Washington State Department of Ecology, with input parameters unique for that region. The
model is built on a continuous simulation HSPF platform and can model the entire hydrological
cycle for multiple years. The purpose of the WWHM3 is to size stormwater control facilities to
mitigate the effects of increased runoff (peak discharge, duration, and volume) from proposed
land use changes that impact natural streams, wetlands, and other water courses. WWHM3
also uses an LID Scenario Generator to show the mean annual distribution of stormwater into
3-286 Chapter 3. Urban and Suburban
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
surface runoff, interflow, groundwater, and evapotranspiration. Using the LID Scenario
Generator, the user can change land use combinations to optimize performance. In addition to
LID Scenario Generator, the user can explicitly model various LID practices, including green
roofs.
The software has been used to develop stormwater systems for the 19 counties in western
Washington State and is designed to comply with the CWA (NPDES Phase I and II), the
Endangered Species Act and State and local stormwater regulations. More information is at
www.ecv.wa.gov/Programs/wq/stormwater/wwhmtraining/wwhm/wwhm v3/index.html.
RECARGA
The RECARGA model was developed by the University of Wisconsin Civil & Environmental
Engineering Department Water Resources Group to provide a design tool for evaluating the
performance of bioretention facilities, rain garden facilities, and infiltration basins. Individual
facilities with surface ponding, up to 3 distinct soil layers and optional underdrains can be
modeled under user-specified precipitation and evaporation conditions. The model continuously
simulates the movement of water throughout the facility (ponding zone, soil layers and
underdrains), records the soil moisture and volume of water in each water budget term
(infiltration, recharge, overflow, underdrain flow, evapotranspiration, and the like) at each time
step and summarizes the results. The results of this model can be used to size facilities to meet
specific performance objectives, such as reducing runoff volume or increasing recharge, and for
analyzing the potential impacts of varying the design parameters. Information is at
http://dnr.wi.gov/runoff/stormwater/technote.htm.
2.3 Simpler Models
The following summarizes several simpler, spreadsheet-based or online, models:
Virginia Runoff Reduction Method Spreadsheets
The Runoff Reduction Method is a system that incorporates site design, stormwater
management planning, and BMP selection to develop the most effective stormwater approach
for a given site. The method relies on a three-step compliance procedures that includes
1) applying site design practices to minimize impervious cover, grading and loss of forest cover,
2) apply runoff reduction practices, and 3) computer pollutant removal by selected BMPs. Two
spreadsheets have been developed, one for new development and one for redevelopment
projects that allow the designer to see whether the phosphorus load reduction has been
achieved by the application of runoff reduction practices, www.dcr.virginia.gov/lr2f.shtml
Chapter 3. Urban and Suburban 3-287
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
LIDQuicksheet 1.2
Developed by the Milwaukee Metropolitan Sewerage District (MMSD), LID Quicksheet 1.2 is a
calculation spreadsheet that has been developed to provide a practical way to calculate how the
use of particular low impact development practices affect the stormwater detention volume
required under Chapter 13. The LID practices included in the Quicksheet are rain gardens, rain
barrels, green roofs, cisterns, and permeable pavement. The intent of the Quicksheet is to allow
the designer to evaluate the effect of LID practices on reducing the volume of traditional
stormwater detention. Information on LID Quicksheet 1.2 is available in Appendix L at
http://v3.mmsd.com/manuals.aspx.
Emeryville Stormwater Sizing Calculator
The City of Emeryville, California developed this spreadsheet-based calculator to determine the
proper size of stormwater treatment devices for new development projects. The spreadsheet
includes 7 tables each targeted to a specific type of stormwater treatment information. The tool
uses user-defined drainage area and types to calculate the required facility size for the area. It
also calculates the amount of shortfall in metered detention areas, bioretention basins, lowered
planter strips, flow-through planter boxes, and bioretention swales. The tool can help track
treatment capacity excess and shortages so that parcel areas can be redistributed if there is a
shortfall. This tool along with others can be accessed at
http://cfpub.epa.gov/npdes/greeninfrastructure/modelsandcalculators.cfm.
Capitol Region Watershed District (Twin Cities, Minnesota), Volume
Reduction Worksheet
This spreadsheet includes formulas for volume reduction practices. Volume credits are provided
for seven different types of practices, www.capitolregionwd.org/permit forms.html
The Center for Neighborhood Technology Green Values Calculator
(GVC)
The GVC compares green infrastructure performance, costs, and benefits to conventional
stormwater practices at both development-site and neighborhood scales. The tool provides a
quantified analysis of green infrastructure environmental benefits including reduced runoff
volume and groundwater recharge. Users can specify site data in a custom run or use several
templates for typical urban and suburban scenarios. A number of green interventions can be
selected and used to calculate financial and hydrologic reduction data. Hydrologic reductions
include lot-level goals for peak and total discharge, desired total site peak discharge, total
detention required, and average annual discharge. The GVC is maintained by The Center for
Neighborhood Technology and is at http://greenvalues.cnt.org.
3-288 Chapter 3. Urban and Suburban
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
SELECT
The System Effectiveness and Life-cycle Evaluation of Costs Tool (SELECT) is a simple
planning-level tool that enables a stormwater manager to examine the effectiveness of
alternative scenarios for controlling stormwater pollution and the whole-life cost associated with
each scenario. SELECT uses a long-term record of hourly rainfall which it translates into runoff
using a runoff coefficient that is related to the effective imperviousness of the catchment. This
runoff is introduced to the BMP (which include a number of common BMPs, including permeable
pavement, wetlands, and swales). If there is capacity in the BMP, the runoff is captured; if the
BMP is full, the runoff is discharged untreated to the receiving waters. The model calculates
total outflow as the sum of what is treated and what is not.
This tool was developed for the Water Environment Research Foundation (WERF) by a team
including ACR, LLC, the University of Utah, and Colorado State University and uses Microsoft
Excel as an interface. SELECT is available only to WERF subscribers. More information,
including how to become a WERF subscriber and download the tool, is at www.werf.org/select.
Upper Neuse Site Evaluation Tool (SET)
The Upper Neuse Site Evaluation Tool (SET) is a spreadsheet-based tool developed by Tetra
Tech, Inc., for the Upper Neuse River Basin Association. It was designed to aid in the
assessment of development plans and available BMPs to achieve regional water quality
objectives. The SET can also be used to compare the costs of stormwater BMP systems and
estimate the cost savings for reducing impervious surfaces within a site design. The most recent
version of the SET can be found at www.unrba.org/set.
The SET has two functioning components—the Hydrology/Pollutant Component for assessing
water quality impacts of development, and the Cost Component for assessing the costs of
BMPs and other infrastructure. The Hydrology/Pollutant Component requires user-controlled
targets for nutrient loading, an optional target for sediment loading, and targets for peak flow for
storage of runoff during the type of storm events most likely to cause downstream channel
erosion. Data entry includes general site data, land use, drainage areas and BMP information.
Various BMPs can be tested to find a combination that meets the targets. The Cost Component
allows a user to compare the costs of stormwater BMP systems and estimate the cost savings
for reducing impervious surfaces within a site design.
Rainwater Harvester Computer Model
North Carolina State University developed a computer model to assist in determining the
appropriate cistern size for a given situation. The model uses rainfall data and anticipated usage
to establish cistern inputs and outputs and provides a cost summary and usage statistics in a
Chapter 3. Urban and Suburban 3-289
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
report form. Version 2.0 includes an improved interface, reduced calculation times, an
interactive graph of cistern levels, and the ability to save and load model inputs. Also, the
website also includes a quick online calculator that provides an overview of the benefits of a
water harvesting system for homeowners, www.bae.ncsu.edu/topic/waterharvesting/model.html
3-290 Chapter 3. Urban and Suburban
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
Appendix 3: Procedures and Case Studies from the
Section 438 Guidance
The following information is from the Technical Guidance on Implementing the Stormwater
Runoff Requirements for Federal Projects under Section 438 of the Energy Independence and
Security Act available at www.epa.gov/owow/NPS/lid/section438.
This appendix includes procedures for calculating the 95th percentile rainfall event, case studies
of stormwater designs to retain the 95th percentile rainfall event, and assumptions related to the
runoff methodology calculations.
Calculating the 95th Percentile Rainfall Event
A long period of precipitation records, i.e., a minimum of 10 years of data, is needed to
determine the 95th percentile rainfall event for a location. Thirty years or more of monitoring data
are desirable to conduct an unbiased statistical analysis. The National Climatic Data Center
(NCDC) provides long-term precipitation data for many locations of the United States. You can
download climate data from their Web site (www.ncdc.noaa.gov) or by ordering compact discs
(NOTE: The NCDC charges a fee for access to their precipitation data). Local airports,
universities, water treatment plants, or other facilities might also maintain long-term precipitation
records. Data reporting formats can vary based on the data sources. In general, each record
should include the following basic information:
• Location (monitoring station)
• Recording time (usually the starting time of a time-step)
• Total precipitation depth during the time-step
In addition to the above information, a status flag is sometimes included to indicate data
monitoring errors or anomalies. Typical NCDC flags include A (end accumulation), M (missing
data), D (deleted data), or I (incomplete data). If there are no flags, the record has passed the
quality control as prescribed by the NCDC and has been determined to be a valid data point.
There are several data processing steps to determine the 95th percentile rainfall event using a
spreadsheet. These steps are summarized below:
1. Obtain a long-term 24-hr precipitation data set for a location of interest (i.e., from the
NCDC Web site).
Chapter 3. Urban and Suburban 3-291
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
2. Import the data into a spreadsheet. In MS Excel [Data / Import External Data / Import Data]
3. Rearrange all of the daily precipitation records into one column if the original data set
has multiple columns of daily precipitation records.
4.
5.
6.
1
2
3
4
5
6
7
8
Q
A
Date
1/2/1921
1/3/1921
1/4/1921
1/5/1921
1/6/1921
1/7/1921
1/8/1921
•i joy-icn-i
B C
Prep
0.05
0
0
0.33
0.08
0.08
0.19
n
; D
Review the records to identify if there are early periods with a large number of flagged
data points (e.g., erroneous data points). Select a long period of good recording data
that represents, ideally, 30 years or more of data. Remove all of the extra data (if not
using the entire dataset).
Remove all flagged data points (i.e., erroneous data points) from the selected data set
for further analysis.
Remove small rainfall events (typically less than 0.1 inches), which may not contribute to
rainfall runoff. These small events are categorized as depressional storage, which, in
general, does not produce runoff from most sites.
1
2
3
4
5
6
7
8
q
ABC D
Date Prep
1/5/1921 0.33
1/8/1921 0.19
1/14/1921 1.04
2/6/1921 0.12
2/11/1921 0.63
2/20/1921 1.33
2/28/1921 0.43
•3WICD1 n -n
Note: Steps 4 through 6 can be processed by applying data sort, delete and re-
sort spreadsheet functions. In MS Excel [Data / Sort]
7. Calculate the 95th percentile rainfall amount by applying the PERCENTILE spreadsheet
function at a cell. In MS Excel [=PERCENTILE(precipitation data range,95%)]
3-292
Chapter 3. Urban and Suburban
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
8.
1
2
3
4
5
6
7
A
Date
1/5/1921
1/8/1921
1/14/1921
2/6/1921
2/11/1921
2/20/1921
B C
Prep
0.33
0.19
1.04
0.12
0.63
1.33
: D E
E F
=PERCENTILE(B:B,95%)
1.52
Note: The PERCENTILE function returns the nth percentile of value in the entire
precipitation data range. This function can be used to determine the 95th
percentile storm event that captures all but the largest 5% of storms.
The 95th percentile was calculated in the previous step. However, if the user would like
to see this information represented graphically and get a relative sense of where
individual storm percentiles fall in terms of rainfall depths, the following methodology can
be used. Derive a table showing percentile versus rainfall depth to draw a curve as
shown below. The PERCENTILE spreadsheet function can be used for each selected
percent. It is recommended to include at least 6 points between 0% and 100% (several
points should be between 80% and 100% to draw an accurate curve).
1
2
3
4
5
c
A
Date
1/5/1921
1/8/1921
1/14/1921
2/6/1921
1/1 1 yicm
B C
Prep
0.33
0.19
1.04
0.12
n KT
; D
Percentile
0%
10%
20%
30%
/inoi
E
F
G
Rainfall
=PERCENTILE(B:B,D2)
=PERCENTILE(B:B,D3)
=PERCENTILE(B:B,D4)
=PERCENTILE(B:B,D5)
-DPDrPMTII P,'R-R RSI
1
2
3
4
5
6
7
8
9
10
11
12
U
14
15
__
17
_
19
20
21
A
Date
1/5/1921
1/8/1921
1/14/1921
2/6/1921
2/11/1921
2/20/1921
2/28/1921
3/3/1921
3/9/1921
3/13/1921
3/25/1921
3/28/1921
4/1/1921
4/9/1921
4/15/1921
4/17/1921
4/18/1921
4/23/1921
4O4/1921
4/30/1921
B C
Prep
0.33
0.19
1.04
0.12
0.63
1.33
0.43
0.13
0.31
0.46
0.47
0.12
0.36
0.69
0.24
0.32
0.55
0.69
0.19
1.44
; D
Percentile
0%
10%
20%
30%
40%
50%
60%
70%
80%
85%
90%
93%
94%
95%
96%
97%
98%
99%
99.5%
100%
E
Rainfall
0.1
0.13
0.17
0.22
0.28
0.36
0.46
0.6
0.79
0.93
1.16
1.35
1.44
1.52
1.65
1.82
2.068
2.508
3.049
7.06
F
7
6
I 5
O
I 1
1
= 3
w
a. 2
1
0
G
H
1
J
K
L
— — i
__ — i
_ 1
^_ -H
|
>— — '
.- '
_- --"
i- ^
Y~*
1
J
•\
*
0% 10% 20% 30% 40% 50% 60% 70% 30% 90% 100%
Peicentile
Chapter 3. Urban and Suburban
3-293
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
Use the spreadsheet software to create of plot of rainfall depth versus percentile, as shown
above. The 95th percentile storm event should correlate to the rainfall depth calculated in step 7,
however the graph can be used to calculate rainfall depths at other percentiles (e.g., 50%,
90%).
3-294 Chapter 3. Urban and Suburban
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
Case Studies on Capturing the 95th Percentile Storm
Using On-site Management Practices
Introduction
This section contains nine case studies that are intended to be representative of the range of
projects that are subject to the requirements legislated in Section 438 of the Energy
Independence and Security Act. The facility examples in the case studies were selected to
illustrate project scenarios for differing geographic locations, site conditions, and project sizes
and types. As noted in Part I, all projects with a footprint greater than 5,000 square feet must
comply with the provisions of Section 438. What this means is that both new development and
redevelopment projects should be designed to infiltrate, evapotranspirate, and/or harvest and
use runoff to the maximum extent technically feasible (METF) to maintain or restore the pre-
development hydrology of the site. Scenarios 1-8 are examples of sites where it was technically
feasible to design the stormwater management system to retain the 95th percentile storm on-
site. Scenario 9, however, was provided as an example of an METF analysis where site
constraints allowed the designers to retain only 75% of the 95th percentile storm.
Given the site-specific nature of individual projects, the case study scenarios described here do
not include site specific design features such as runoff routing, specific site infiltration rates, the
structural loading capacity of buildings, and such in terms of stormwater practice selection.
It should be noted that an example of Option 2, which requires a site-specific hydrologic
analysis, has not been provided in this document because of the complexity of factors and the
lack of general applicability such an analysis would have.
Background
Numerous approaches exist for determining the volume of runoff to be treated through
stormwater management. Retaining stormwater runoff from all events up to and including the
95th percentile rainfall event was identified as Option 1 because small, frequently-occurring
storms account for a large proportion of the annual precipitation volume. Using GI/LID practices
to retain both the runoff produced by small storms and the first part of larger storms can reduce
the cumulative impacts of altered flow regimes on receiving water hydrology, e.g., channel
degradation and diminished baseflow. For the purposes of this guidance, retaining all storms up
to and including the 95th percentile storm event is analogous to maintaining or restoring the pre-
development hydrology with respect to the volume, flow rate, duration and temperature of the
runoff for most sites.
Chapter 3. Urban and Suburban 3-295
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
Determination of the 95th Percentile Rainfall Event
The 95th percentile rainfall event was determined using the long-term daily precipitation records
from the National Climate Data Center (NCDC 2007). By analyzing the frequency and rainfall
depths from daily rainfall records over 24-hour periods, the 95th percentile storm event can be
determined. From a frequency analysis viewpoint, the 95th percentile event is the storm event
that is greater than or equal to 95% of all storms that occur within a given period of time.
Regional climate conditions and precipitation vary across the U.S. Because of local values, it is
essential that the implementing agency or department establish the 95th percentile storm event
for the project site since the control volume may vary depending on local weather patterns and
conditions.
On-site Stormwater Management Practice Determinations
For the purposes of the case study scenarios, the following four categories of practices were
selected as the most appropriate practices for implementing Section 438 requirements:
bioretention, permeable pavements and pavers, cisterns, and green roofs. These practices were
selected based on known performance data and cost. For each case study, the same hierarchy
of selection criteria was used, i.e., the most cost effective practices were considered before
other practices were considered. Bioretention practices were considered first because these
systems generally have the lowest cost per unit of stormwater treated (Hathaway and Hunt
2007). Thus, if the bioretention system could not be designed to adequately capture the desired
runoff volume, permeable pavement and pavers, cisterns, and green roofs were considered in
that order based on relative cost. In most cases a combination of practices was selected as part
of an integrated treatment system. It should be noted that all treatment systems were designed
to accomplish the goal of capturing the 95th percentile rainfall event on-site. Examples of on-site
stormwater management practices selected for each site are presented in the results section.
For the Boston, MA site, it was assumed that bioretention was not feasible to simulate a
situation where space was severely limited; as a result, interlocking modular pavers were
selected as the most cost-effective stormwater management to capture the requisite design
volume. To further illustrate the range of site conditions designers may encounter, and how site
conditions impact the selection of appropriate control options, Scenario #3 (Cincinnati, OH) was
re-analyzed as Scenario #8. In Scenario #8, it was assumed that the site had clay soils and low
infiltrative capacity. Given these site conditions, the range of potential control options was more
limited and a combination of modular paving blocks, a green roof, and cisterns was ultimately
selected based on cost and site suitability factors.
For purposes of these modeling exercises, a number of assumptions were associated with each
category of practice. These assumptions are not necessarily an endorsement of a particular
design paradigm, but rather were used to keep a somewhat conservative cap on the scenarios
3-296 Chapter 3. Urban and Suburban
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
to demonstrate the feasibility of the approach. For example, bioretention retrofits can and should
often be located in prior impervious locations; however, in all modeled scenarios bioretention
was restricted to currently landscaped areas. The assumptions were:
• Bioretention areas: On-lot retention of stormwater through the use of vegetation, soils,
and microbes to capture, treat and infiltrate runoff.
It is assumed bioretention practices would be installed within currently landscaped
pervious areas or that pervious areas would be created for bioretention cells. While
termed bioretention, these systems are designed to provide infiltration as well as
temporary storage. Bioretention areas would be designed to accept up to a depth of 10
inches of water across the surface of the bioretention cell (see Resources at end of this
Appendix). The conceptual design of this storage depth would occur within the media
and/or could be included as ponded storage. Further design storage beyond the 10
inches would be acceptable (and encouraged) above the media on a site-by-site basis
with ponded depth generally not to exceed 12 inches.
Uniform infiltration was assumed across the entire base of the bioretention cell. No
additional media underneath the amended soils were included in the designs with
infiltration rates in this layer governed by the in situ soils. Underdrains were not modeled
directly but could be applied at the point of storage overflow such that no overflow
occurs until the design depth of 10 inches is saturated. This approach was selected to
maximize the storage and infiltration benefits of these systems. Designs utilizing
underdrains at the base of the bioretention cell do not store the requisite volumes
because the media is permeable and the underdrain conveys the runoff offsite through
the underdrain before it can be infiltrated. Because standard underdrains typically
discharge from smaller storms as well, underdrain designs, if employed, should ensure
adequate retention capacity for the 95th percentile event volume.
The bioretention footprint for modeling purposes was calculated as one uniform area that
did not include side slopes. There is an expectation that actual bioretention cell
construction would be distributed throughout the site with targeted locations based on
hydrology (natural flow paths) and soils with greater infiltrative capacity. Side slopes may
increase the surface excavation area required to accommodate the footprint and
freeboard of these systems depending on the design or the bioretention system.
• Porous/permeable pavement: Transportation surfaces constructed of asphalt, concrete
or permeable pavers that are designed to infiltrate runoff.
Infiltration was modeled for the entire porous pavement area with drainage pipes used
only as overflow outlets. This design was chosen to maximize infiltration capabilities of
the system. While many types of porous pavement systems can be used, modular block
type pavers were generally applied in this design category under the assumption that
Chapter 3. Urban and Suburban 3-297
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
they typically include sufficient volumetric storage in the media layer. [Note: Other types
of porous pavement applications are available that support heavy loads and can be
designed to temporarily store and infiltrate runoff beneath the surface of the pavement.]
For these systems, an equivalent of 2 inches of design storage depth was assumed.
This design depth could be achieved by specifying 10 inches of media depth that had
20% void space. Similarly, this could be achieved by designing six inches of media
depth above the bottom surface, with specified media containing 33% void space. This
alternative would have the overflow outlet at the 6 inch depth providing an equivalent
water storage depth of 2 inches.
The soils under the paver blocks may require or be subjected to some compaction for
engineering stability. As a result, infiltration into underlying soils was modeled
conservatively by applying the minimum infiltration rate for each soil type (see
Resources at end of this Appendix).
Generally, porous pavement is not recommended for high traffic areas or loading bays
Because of this the scenarios assumed that only a percentage of total parking and road
areas on a site can be converted to porous pavement. The assumed maximum
percentage applied in the scenarios was set at 60% of the total paved area. Guidance
on porous pavements is available at:
http://cfpub.epa.gov/npdes/greeninfrastructure/technology.cfmtfpermpavements
Cistern: Containers or vessels that are used to store runoff for future use.
Cisterns were modeled in cases where green roofs were not feasible or where it was
necessary to include additional storage volume to meet the goal of on-site rainfall runoff
capture. The sizes of cisterns would be calculated based on site-specific rainfall, site-
specific spatial and structural conditions, use opportunities and rates, and consideration
of cost per volume of storage. For simplicity, cistern volume was reported as a total
volume. This total volume could be subdivided into any number of cisterns to provide the
total necessary storage but should be based on the impervious area and runoff
quantities which will flow to the cistern. The most efficient cost per volume storage would
need to be considered on a site-by-site basis (see Resources at end of this Appendix).
Green roof: Roof designed with light weight soil media and planted with vegetation.
Frequently, green rooftop area is limited by structural capacity. In addition, other rooftop
equipment may need to be accommodated in this space including HVAC systems and
air handlers. For this reason, and to provide a somewhat conservative rate of
application, it was assumed for these modeling analyses that up to 30% of a roofs
impervious area could be converted into a green roof. Green roof area was assumed to
3-298 Chapter 3. Urban and Suburban
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
have 1 inch of total effective stormwater storage, i.e., a 2.5-inch media depth with 40%
void space (see the Resources at end of this Appendix).
General Approach
Using site aerial photos, spatial analysis should be conducted to estimate the land cover types
and areas for each site. The surface conditions of each site can be digitized using geographic
information systems (GIS) techniques. Alternatively, computer-aided design (CAD) drawings
can be used to estimate the surface area of each land cover type. The schematic in Figure
3A3-1 illustrates the processes used for selecting and determining the overall size of stormwater
management practices for each site.
The following steps provide more detailed information on acquiring and calculating the
necessary data to complete the processes indicated in Figure 3A3-1. This methodology was
used in the scenario analyses that follow.
Collecting spatial data for a site
1. Collect an aerial orthophotograph for the desired site.
2. Digitize land use/land cover conditions using GIS techniques. If CAD drawings of the site
exist, they can be used to estimate land cover area (pervious, impervious).
3. Categorize the digitized or planned land use/land cover based on surface hydrologic
conditions, e.g., rooftop, pavement, and pervious/landscaped area.
4. Estimate the size of each land use/land cover category (by polygon).
Determining the 95th percentile, 24-hour rainfall event
1. Obtain a long-term 24-hr precipitation data set for the location of interest (i.e., from the
NCDC Web site or other source).
2. Import the data into a spreadsheet. In MS Excel [Data / Import External Data / Import Data]
3. Rearrange all of the daily precipitation records into one column if the original data set
has multiple columns of daily precipitation records.
4. Remove all flagged data points (i.e., erroneous data points) from the selected data set
for further analysis.
5. Remove small rainfall events (typically less than 0.1 inches) that may not contribute to
rainfall runoff. These small storms often produce little if any appreciable runoff from most
sites and for modeling purposes are typically considered as volume captured in surface
depression storage.
Chapter 3. Urban and Suburban 3-299
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
Stormwater
Management Analysis &
Design Process
Collect spatial data from aerial
photos (determine pervious
and impervious areas)
X
Collect historic rainfall
data from nearest station
Determine the 95th percent!le
24-hour rainfall event
z
Estimate the current runoff
Select onsite control measure options
Check whether control
measure options meet
performance goals
Determine the size(s) of control measure(s)
Select control
measure(s) to fit the site
and confirm performance
Yes
No
1. Select alternative control measures
using METF analysis and site
limitations to determine appropriate
runoff control measures if
performance goals cannot be
achieved
and/or
2. Exercise optional offsite runoff
management approach and select
appropriate control measures
Determine location and size(s) of
onsite or off-site control measures
Design and implement control measure(s)
Figure 3A3-1. Flow chart depicting the process for determining control measures using the
95 percentile, 24-hour, annual rainfall event.
3-300
Chapter 3. Urban and Suburban
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
6. Calculate the 95th percentile rainfall volume by applying the PERCENTILE spreadsheet
function to a range of data cells. The PERCENTILE function returns the nth percentile
value in the specified precipitation data range. This function can be used to determine
the 95th percentile storm event that captures all but the largest 5% of storms. In MS
£xce/[PERCENTILE(precipitation data range,95%)]
Estimating current runoff and placing on-site control measures to capture the 95th
percentile rainfall event
1. Collect spatial data for a site, e.g., rooftop, pavement, and pervious areas as above.
2. Check soil type (USDA mapping, borings, or on-site testing) for the site to determine
infiltration parameters. For this modeling, many of the assumptions that pertain to
generalized soils groups and their infiltration properties come from the EPA Stormwater
Management Model (SWMM 4.x) manual (see Resources at end of this Appendix).
3. Determine the current runoff volume that would occur during a 24 hour period by
applying the 95th percentile rainfall to the existing site conditions (land use and soil
properties) as above using a hydrologic model (such as TR-55 or SWMM). For this
analysis, it is assumed that the rainfall amount is distributed over a 24 hour period.
Actual rainfall event duration (and intensity) was not considered for determining rainfall
runoff (however, timing was considered when modeling infiltration).
4. Determine flow paths so that management practice placements are in locations where
flows can be intercepted and routed to practices. Because this is a site specific effort
and may require detailed topographic information or further surveys this would be a task
to be completed on-site and therefore is not included as a part of the modeling scenario
exercise.
5. Select on-site control practices to capture the current 95th percentile runoff event; base
the selection of appropriate options on site conditions, areas available for treatment
options, and other factors such as site use and other constraints.
Note: The steps above have been generalized for the purposes of this guidance. It is
recommended that a qualified professional engineer determine or verify that stormwater
management practices are sized, placed, and designed correctly. It should also be noted that
the methodology to determine rainfall amount used a 24 hour time period based on daily
records. Actual rainfall events may have occurred over shorter or longer time periods. Similarly,
for modeling purposes, the 24 hour rainfall amount was distributed to pervious and impervious
areas (and management practices) as a uniform event occurring during a 24-hour period. A
large dataset (greater than 50 years) was used to reasonably represent rainfall depth on a daily
Chapter 3. Urban and Suburban 3-301
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
bases. It stands to reason that more frequent, shorter duration precipitation events are better
represented than less frequent, longer duration precipitation events.
Scenarios
Eight locations were selected for the 9 case studies as shown in Figure 3A3-2 and Table 3A3-1.
Case study numbers 3 and 8 were both developed based on the Cincinnati, Ohio facility,
although the site parameters were altered to represent differing site conditions and design
constraints. Annual average rainfall depths for these locations range from 7.5 inches to 48.9
inches. Analyses of the 95th percentile rainfall events for these locations produced rainfall
depths that range from 1.00 inch to 1.77 inches (Table 3A3-1).
Portland
Boston
*
Denver
Cincinnati
Charleston * Norfolk
Phoenix
Atlanta
Figure 3A3-2. Locations for analyzing on-site control measures.
The government facilities in the 8 case study locations were selected because they represent
generic sites from the major climatic regions of the U.S. These facilities also were selected
because the sites have a range of site characteristics that can be used to illustrate different site
designs and stormwater management options, e.g., pervious, roof, and pavement areas (Table
3A3-2). Site sizes ranged from 0.7 to 27 acres with percent site imperviousness area ranging
from 47% to 95% of the site. Aerial photos of the sites are included along with site specific
rainfall runoff and soil results.
3-302
Chapter 3. Urban and Suburban
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
Table 3A3-1. Summary of rainfall data for the seven locations
No
1
2
3
4
5
6
7
8
Location
Charleston, WV
Denver, CO
Cincinnati, OH
Portland, OR
Phoenix, AZ
Boston, MA
Atlanta, GA
Norfolk, VA
NCDC daily precipitation data
Period of record
1/1/1948-12/31/2006 (59 yrs)
1/1/1948-12/31/2006 (59 yrs)
1/1/1948-12/31/2006 (59 yrs)
1/1/1941-12/31/2006 (66 yrs)
1/1/1948-12/31/2006 (59 yrs)
1/1/1920-12/31/2006 (87 yrs)
1/1/1930-12/31/2006 (77 yrs)
1/1/1957-12/31/2006 (50 yrs)
Coverage
99%
96%
96%
98%
99%
99%
100%
99%
Rainfall depth
(inches)
Annual
average
43.0
15.2
36.5
35.8
7.5
41.9
48.9
45.4
95th percentile
rainfall event
1.23
1.07
1.45
1.00
1.00
1.52
1.77
1.68
The results of the spatial analyses were summarized and divided into three land cover
categories; rooftop, pavement, and pervious area, as shown in Table 3A3-2.
Table 3A3-2. Summary of land-use determinations of the study sites
No
1
2
3
4
5
6
7
8
Location
Charleston, VW
Denver, CO
Cincinnati, OH
Portland, OR
Phoenix, AZ
Boston, MA
Atlanta, GA
Norfolk, VA
Facility spatial info
(acres)
Rooftop
0.1
0.5
1.6
8.8
0.2
0.9
3.9
0.9
Pavement
0.4
1.9
8.0
16.9
0.7
1.5
10.8
0.55
Pervious
0.2
2.0
9.4
1.3
1.1
1.1
6.2
0.15
Total
0.7
4.5
19
27
2
3.5
21
1.6
Site
imperviousness
73%
55%
51%
95%
47%
69%
70%
91%
Methods for Determining Runoff Volume
Direct Determination of Runoff Volume
Runoff from each land cover was estimated using a simplified volumetric approach based on the
following equation:
Runoff = Rainfall - Depression Storage - Infiltration Loss
Chapter 3. Urban and Suburban
3-303
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
Again, this methodology does not consider routing of runoff; therefore slope is not considered
when calculating on a volumetric basis.
Infiltration loss is calculated only in pervious areas (e.g., there is no infiltration in impervious
areas). In this analysis, infiltration was estimated using Morton's equation:
it = 'min + ('max ~~ 'min) 6 — K t
where
Ft= infiltration rate at time t (in/hr)
/min = minimum or saturated infiltration rate (in/hr)
/max = maximum or initial infiltration rate (in/hr)
k = infiltration rate decay factor (/hr) and
t = time (hr) measured from time runoff first discharged into infiltration area
Infiltration loss for the 24-hr rainfall duration was estimated by the following equation with
assumptions of a half hour At and uniform rainfall distribution in time:
Infiltration Loss = £ (f -A/)
To more accurately describe the dynamic process of infiltration associated with Morton's
equation, infiltration loss was integrated over a 24-hour period using a half hour time step while
applying the maximum and minimum infiltration rates (in/hr) with time using the appropriate soil
decay factor. The results of this process are further illustrated in the Resources section at the
end of this Appendix.
Once runoff from each land cover was estimated, the total runoff from a site can be obtained
using an area-weighted calculation as shown below:
RunoffsAe ={(Runoffroot xAmot)+(Runoffpavemeni *Apavemeni)+(Runoffpenious x/\pervious)}/>4site
Where Runoff^ = total runoff from the site (inches); X\site = site area (acres); Runoffroo1 = runoff
from rooftop (inches); X\roof = rooftop area (acres); Runoffpavemeni = runoff from pavement area
(inches); Apavemeni = pavement area (acres); Runoffpen-tous = runoff from pervious area (inches);
and X\pervious = pervious area (acres).
An example demonstrating how to calculate runoff by applying the Direct Determination method
is presented below using the Charleston, WV (Scenario #1) site condition presented in Tables
3A3-1 and 3A3-2.
3-304 Chapter 3. Urban and Suburban
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
Runoff^ = 95th Rainfall - Depression Storage
= 1.23-0.1 = 1.13 inches
= 95th Rainfall - Depression Storage
= 1.23-0.1 = 1.13 inches
= 95th Rainfall - Depression Storage - Infiltration Loss
= 1.23-0.1 -9.73 = 0 inches (i.e., no runoff because the result is a
negative number)
RunoffsAe ={(Runoffmot xAroot)+(Runoffpavemeni xApavemeni)+(Runoffpenious xX\pervious)}/X\site
={(1.13x0.10)+(1.13x0.41)+(OxQ.19)}/0.7 = 0.82 inches
Infiltration loss was estimated based on soil type B by applying the Morton equation as
described above. Because the volume removed from surface runoff through infiltration was
substantial, no runoff occurred from the pervious area.
In cases where sites had limited physical space available for stormwater management, a series
of practices was used (e.g., treatment train) to simulate the runoff and infiltrative behavior of the
system. For example, if there was inadequate area and infiltrative capacity to infiltrate 100
percent of the 95th percentile storm event within a bioretention system another on-site
management practice was selected to manage the runoff that could provide the necessary
capacity. In this manner, excess runoff was routed to another management practice in the
series of treatment cells where possible.
Two types of soils were considered for every site: hydrologic soil group B and C (except for
scenario 8 in which hydrologic soil group D was used). Group B soils typically have between 10
percent and 20 percent clay and 50 percent to 90 percent sand and either loamy sand or sandy
loam textures with some loam, silt loam, silt, or sandy clay loam soil textures placed in this
group if they are well aggregated, of low bulk density, or contain greater than 35 percent rock
fragments. Group C soils typically have between 20 percent and 40 percent clay and less than
50 percent sand and have loam, silt loam, sandy clay loam, clay loam, and silty clay loam soil
textures with some clay, silty clay, or sandy clay textures placed in this group if they are well
aggregated, of low bulk density, or contain greater than 35 percent rock fragments (USDA-
NRCS 2007). The application of these hydrologic soil groups was intended to give reasonable
and somewhat conservative estimates of infiltration capacity.
General hydrologic parameters in this analysis were assumed as follows (see Resources at the
end of this Appendix for citations of assumptions):
• Depression storage (or initial abstraction)
- Rooftop: 0.1 inches
- Pavement: 0.1 inches
Chapter 3. Urban and Suburban 3-305
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
- Pervious area: 0.2 inches
• Morton Infiltration parameters
- Hydrologic Soil Group B
- Maximum infiltration rate: 5 in/hr
- Minimum infiltration rate: 0.3 in/hr
- Decay factor: 2 /hr
- Hydrologic Soil Group C
- Maximum infiltration rate: 3 in/hr
- Minimum infiltration rate: 0.1 in/hr
- Decay factor: 3.5 /hr
• Design storage assumptions of control measures
- Bioretention: up to 10 inches (but variable based on balancing necessary storage
volume, media depth for plant survivorship, and surface area limitations)
- Green roof: 1 inch (2.5 inches deep media with 40% void space)
- Porous pavement: 4 inches (10 inches deep media with 40% void space)
Other Methods for Estimating Runoff Volume
Runoff from a site after applying the 95th percentile storm can be estimated by using a number
of empirical, statistical, or mathematical methods. Several methods were considered in this
analysis. The Rational Method can be used to estimate peak discharge rates and the Modified
Rational Method can be used to develop a runoff hydrograph. The NRCS TR-55 model can be
used to predict runoff volume and peak discharge. TR-55 can also be used to develop a runoff
hydrograph. The EPA Stormwater Management Model (SWMM) can be used to simulate
rainfall-runoff, pollutant build-up and wash-off, transport-storage-treatment of stormwater flow
and pollutants, backwater effects, and such for a wide range of temporal and spatial scales. The
SWMM model can be fit to model a small site with a distributed system. Hydrologic Simulation
Program - Fortran (HSPF, USDA) is a watershed and land use based lumped model that can
be used to compute the movement of water and pollutants when evaluating the effects of land
use change, reservoir operations, water quality control options, flow diversions, and such. In
general, regionally calibrated modeling parameters are incorporated into HSPF. QUALHYMO is
a complete hydrologic and water quality model, which can be used to factor in snowmelt or soil
3-306 Chapter 3. Urban and Suburban
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
moisture conditions or to simulate system behavior based on infiltration and ET, ground water
storage tracking, baseflow and deep volumetric losses, and other variables.
Many of the existing tools for analyzing distributed systems use some part or all of the principles
or formulae of the modeling approaches highlighted above. For example, the Emeryville
spreadsheet control measure model (Emeryville, CA) uses a runoff coefficient (i.e., Rational
Method) for analyzing lot-level to neighborhood-scale control measure sizing. The Green
Calculator (Center for Neighborhood Technologies) estimates the benefit of on-site GI/LID
options on a neighborhood-scale by applying the curve numbers (i.e., TR-55) and the Modified
Rational Method. The Northern Kentucky Spreadsheet Tool uses a TR-55 based approach for
control measure sizing on neighborhood or site level spatial scales. The WWHM (Western
Washington Hydrology Model) is a regionally calibrated HSPF model intended for use in sizing
stormwater detention and water quality facilities to meet the Washington State Department of
Ecology standards. WBM-QUALHYMO is a Canadian model used in conjunction with the Water
Balance Model (WBM). This model can be used to continuously simulate stormwater storage
routing, stream erosion, drainage area flow routing, and snowmelt runoff (and ultimately freeze-
thaw). Table 3A3-3 contains a summary of these different methods based on generic modeling
features.
Table 3A3-3. Potential methods for analyzing control measures
Model considerations
Temporal
scale
Spatial
scale
Outputs
Single Event
Continuous
Simulation
Lot-level
Neighborhood
Regional
Peak
Discharge
Runoff
Volume
Hydrograph
Water Quality
Rational
method
Yes
No
Yes
Yes
Yes
Yes
Yes
Yesa
No
TR-55
Yes
No
Yesb
Yes
Yesc
Yes
Yes
Yes
No
SWMM
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Direct
determination
Yes
Possible
Yes
Yes
No
No
Yes
No
Possible
HSPF
Yes
Yes
No
Possible
Yes
Yes
Yes
Yes
Yes
QUALHYMO
Yes
Yes
No
Possible
Yes
Yes
Yes
Yes
Yes
3 Modified Rational Method
b No less than 1 acre.
c No more than 25 square miles (up to 10 subareas).
Chapter 3. Urban and Suburban
3-307
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
From the viewpoint of modeling both lot-level and neighborhood scale projects, the Rational
Method, NRCS TR-55, SWMM, and Direct Determination approaches were selected for use in
scenario analyses. Strength and weakness of these methods are presented in Table 3A3-4.
Table 3A3-4. Comparison of approaches for determining runoff volume
Method
Direct
determination
Rational
method
TR-55
SWMM
Strengths
• Methodology for runoff determination
is same as SWMM
• Models basic hydrologic processes
directly (explicit)
• Simple spreadsheet can be used
• Method is widely used
• Simple to use and understand
• Method is widely used
• Simple to use and understand
• Method is widely used
• Can provide complete hydrologic and
water quality process dynamics in
stormwater analysis
Weaknesses
• Direct application of Morton's method
may estimate higher infiltration loss,
especially at the beginning of a storm
• Does not consider flow routing
• Cannot directly model storage-oriented
on-site control measures
• May not be appropriate for estimating
runoff from small storm events
because depression storage is not well
accounted for
• Needs a number of site-specific
modeling parameters
• Generally requires more extensive
experience and modeling skills
Each method requires specific parameters for estimating runoff from a site. Runoff coefficients
for the Rational Method are assumed to be 0.9 for rooftop and pavement areas, and 0.1 and
0.135 for Group B and C soil pervious areas, respectively (Caltrans 2003). The slope of the
pervious area was assumed to be an average of 2%. Applying these runoff coefficients for each
surface, the overall area-weighted runoff coefficient can be determined.
When applying the NRCS TR-55 method, Curve Numbers (CNs) should be determined for each
drainage area. For rooftop and pavement areas the CN was assumed to be 98, and pervious
area CN was determined on the basis of the hydrologic soil group and the status of grass cover
condition. Curve numbers for pervious areas were assumed to be 61 and 74 for Group B and C
soils, respectively, with an assumption of over 75% grass cover. The overall CN can be
estimated by using an area-weighted calculation (USDA-SCS 1986).
In SWMM modeling, infiltration was modeled using Morton's equation. The same infiltration
parameters and depression storage values used in the direct determination method of runoff
treatment volume described earlier were applied to the SWMM analyses. The average slope of
the pervious area was again assumed to be 2%. The same uniform rainfall distribution and time
step was applied for the SWMM model runs.
3-308
Chapter 3. Urban and Suburban
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
Runoff Methodology Results
Stormwater management practice sizes (and depth) were determined using the Direct
Determination approach to capture the volume of runoff generated in a 95th percentile rainfall
event at each location. Total acreage, impervious area, the 95th percentile rainfall event, the
current expected runoff for the 95th percentile rainfall event, and the future runoff with
stormwater management controls were reported for each site. Results were summarized for the
two soil types (three soil types for scenarios #3 and #8 in Cincinnati). The spatial location of on-
site control measures was also illustrated in the site aerial photo figures. Note that site practices
were placed only on undeveloped or landscaped areas without regard for true flow paths or
technical feasibility. It may be preferred to place practices in existing impervious areas, if
possible. For the purposes of this modeling exercise, the least cost and most practical solutions
were used, i.e., locating bioretention systems on undeveloped or landscaped areas. On an
actual site, flow paths would be determined and berms and swales might be used to route runoff
to areas that are most suitable for infiltration. In other cases, areas that are currently impervious
could be modified to accept runoff, e.g., impermeable pavements removed and replaced by
permeable, sidewalks could be redesigned to include sidewalk bioretention cells and streets
could be designed with flow through or infiltration curb bumpouts/raingardens.
To compare other approaches of runoff estimation, alternate methodologies were also
employed for three scenarios. TR-55 was used for Scenario #1 (Atlanta), the Rational Method
was applied to Scenario #2 (Denver), and the SWMM was run for Scenario #7 (Charleston).
Although flood control is not the focus of this guidance, most localities have flood control
requirements that will need to be considered in designing control measures to comply with
Section 438. For flood control purposes, TR-55 was used to model the 10 year frequency
design storm for each site under the assumption that all stormwater management practices
were in place. The 10-year design storms were selected from the NRCS TR-55 Manual (USDA
1986) for both the Eastern U.S. and the Western U.S. Precipitation Frequency Maps
(www.wrcc.dri.edu/pcpnfreq.html). The 10-year frequency design storm was selected because it
represents a common design standard used by state and local governments to manage peak
rates of runoff and prevent flooding.
Cost Estimates for Selected Scenarios
Scenarios #2 and 7 include cost estimates comparing the capital costs for a design to comply
with Section 438 (retention of the 95th percentile rainfall event) and capital costs for a traditional
stormwater management design (e.g., typical curb and gutter, off-site pond for stormwater
management). These costs are based on average unit costs to construct both traditional and
GI/LID controls.
Chapter 3. Urban and Suburban 3-309
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
Scenario #1 - Charleston, West Virginia
A 0.7-acre site with 73% impervious area was selected from Charleston, West Virginia (Figure
3A3-3). If the 95th percentile rainfall event (1.23 inches) occurred on the existing site (i.e., with
no control measures), 0.82 inches of runoff using the Direct Determination method would be
generated and require management. The runoff from the 95th percentile rainfall event could be
retained by the installation of bioretention systems totaling 0.03 acres if hydrologic soil group B
is present, or 0.06 acres if hydrologic soil group C (Table 3A3-5) is the predominant soil type on
the site. Assuming that bioretention practices are placed in areas that are currently pervious or
landscaped, a total of 0.2 acres of pervious area would be available for the placement of
bioretention systems. The effective design storage depth within the designated bioretention area
was 8 inches.
Figure 3A3-3. Actual site and on-site control measures (Charleston, WV).
3-310
Chapter 3. Urban and Suburban
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
Table 3A3-5. Estimated sizes of on-site control measures for Scenario #1 (Charleston, WV)
Total Area (acres)
Estimated Imperviousness (%)
95th Percentile Rainfall Event (inches)
Expected Runoff for the 95th Percentile Rainfall Event (inches)
Stormwater Management Area Required
Bioretention estimated by Direct Determination method (acres)
Bioretention estimated by SWMM (acres)
Off-site storage necessary to control the 10-yr
event of 3.9 inches (acre-ft)
With on-site controls
Without on-site controls
0.7
73%
1.23
0.82
Hydrologic Soil Group
B
0.03
0.03
0.10
0.16
C
0.06
0.05
0.12
0.17
Note: The two hydrologic methods used (direct determination and SWMM) estimated similar bioretention sizes.
Chapter 3. Urban and Suburban
3-311
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
Scenario #2 - Denver, Colorado
A 4.5-acre site with 55% impervious area was selected from Denver, Colorado (Figure 3A3-4). If
the 95th percentile rainfall event (1.07 inches) occurred on the existing site (i.e., with no control
measures), 0.53 inches of runoff from the site would be generated and require management.
The runoff from the 95th percentile rainfall event could be retained by the installation of
bioretention systems totaling 0.16 acres if the hydrologic soil group B is present or 0.3 acres if
hydrologic soil group C (Table 3A3-6) is the predominant soil type on the site. Assuming that
bioretention practices are only placed in areas that are currently pervious or landscaped, a total
of 2 acres of pervious area is available for the placement of bioretention systems. The design
storage depth of media within the designated bioretention area was 6 inches.
Figure 3A3-4. Actual site and on-site control measures (Denver, CO).
3-312
Chapter 3. Urban and Suburban
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
Table 3A3-6. Estimated sizes of on-site control measures for Scenario #2 (Denver, CO)
Total Area (acres)
Estimated Imperviousness (%)
95th Percentile Rainfall Event (inches)
Expected Runoff for the 95th Percentile Rainfall Event (inches)
Stormwater Management Area Required
Bioretention estimated by the Direct Determination method (acres)
Bioretention estimated by Rational Method (acres)
Off-site storage necessary to control the 10-
yr event of 3.2 inches (acre-ft)
With on-site controls
Without on-site controls
4.5
55%
1.07
0.53
Hydrologic Soil Group
B
0.16
0.16
0.35
0.64
C
0.3
0.28
0.52
0.64
Cost estimates were also developed for this scenario (Table 3A3-7) to compare the costs of
installing on-site control measures to retain the 95th percentile rainfall event versus the costs to
install traditional stormwater management controls (e.g., curbs and gutters combined with off-
site retention such as extended detention wet ponds). In a GI/LID scenario, the bioretention cell
would occupy a specified area. This same area in a traditional design would be covered in turf
since the pond would typically be offsite and not occupy the area planted in turf. Table 3A3-7
includes this cost under the traditional column. Note: typical land development practices involve
mass clearing and grading so little or no pre-existing vegetation is typically retained. It is also
assumed that the use of GI/LID practices would require less underground infrastructure
because the traditional design typically routes stormwater underground to an off-site pond via
pipes or culverts while GI/LID practices are designed to manage runoff on-site and as close to
its source as possible. They are also dispersed across the site and routing occurs through
surface drainage via bioswales and overland flow. As a result GI/LID practices do not require as
much or any hard or grey infrastructure. The cost estimates were developed for Hydrologic Soil
Group B.
Chapter 3. Urban and Suburban
3-313
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
Table 3A3-7. Estimated costs for Scenario #2 (Denver, CO)
Sizes of on-site control practices
Rainfall depth
(in)
Bioretention (acres)
Paver blocks (acres)
Green roof (acres)
Off-site Pond
Total Off-Site
WQV (ac-ft)
10-YrFldCntr
(ac-ft)
Requirement (ac-ft)
Land Area (assumes avg 3 ft
depth)
% of the site
Controls for 95th Percentile Event
1.07
0.1
0
0
-
0.15
0.15
0.05
2.8%
Traditional Stormwater Controls
0.18
0.14
0.32
0.11
Costs of on-site control practices
Biorention/alternative
Off-site Pond
Infrastructure
WQV (ac-ft)
10-YrFldCntr
(ac-ft)
Pipe
Inlet
Land Area (assumes $300K/acre)
Sum
% difference from Traditional
$32,495
$10,073
$8,990
$9,920
$14,500
$75,978
-17.3%
$4,187
$14,833
$9,527
$16,982
$14,880
$31,500
$91,909
3-314
Chapter 3. Urban and Suburban
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
Scenario #3 - Cincinnati, Ohio
A 19-acre site with 51% impervious area was selected in Cincinnati, Ohio (Figure 3A3-5). If the
95th percentile rainfall event (1.45 inches) occurred on the existing site (i.e., no control
measures were in place), 0.68 inches of runoff from the site would be generated and require
management. The runoff from the 95th percentile rainfall event could be retained by the
installation of bioretention systems totaling 0.8 acres if the hydrologic soil group B is present or
1.3 acres if hydrologic soil group C (Table 3A3-8) is the predominant soil type on the site.
Assuming that bioretention practices are only placed in areas that are currently pervious or
landscaped, a total of 9.4 acres of pervious area is available for the placement of bioretention
systems. The design storage depth of media within the designated bioretention area was 8
inches.
^T^« ~"~~»,?"r L'VJ Bio-retention
"•
Figure 3A3-5. Actual site and on-site control measures (Cincinnati, OH).
Chapter 3. Urban and Suburban
3-315
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
Table 3A3-8. Estimated sizes of on-site control measures for Scenario #3 (Cincinnati, OH)
Total Area (acres)
Estimated Imperviousness (%)
95th Percentile Rainfall Event (inches)
Expected Runoff for the 95th Percentile Rainfall Event (inches)
Stormwater Management Area Required
Bioretention estimated by the Direct Determination (acres)
Off-site storage necessary to control the 1 0-yr
event of 4.2 inches (acre-ft)
With on-site controls
Without on-site controls
19
51%
1.45
0.68
Hydrologic Soil Group
B
0.8
2.42
3.29
C
1.3
3.24
3.73
3-316
Chapter 3. Urban and Suburban
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
Scenario #4 - Portland, Oregon
A 27-acre site with 95% impervious area was selected in Portland, Oregon (Figure 3A3-6). If the
95th percentile rainfall event (1.0 inches) occurred on the existing site (i.e., no control
measures), 0.86 inches of runoff would be generated and require management. This site has
the greatest imperviousness among the 7 sites.
Given these site conditions, there is not enough pervious area to manage the entire runoff
volume discharged by the 95th percentile rainfall event with bioretention. As a result, other
practices were evaluated and selected. The practices integrated into the design included a
green roof, cisterns, and porous pavement. Based on the technical considerations of
constructing and maintaining control measures at the site, it was assumed that approximately
30% of the available pervious area could be converted into bioretention cells; 20% of total
rooftop area could be converted into green roofs; 40% of paved area could be converted into
paver blocks; and 50,000 gallons of total volume could be captured in cisterns for use on this
urbanized site. Using this system of four different practices, all runoff for the 95th percentile
rainfall event would be retained (Table 3A3-9).
Bio-retention Porous Pavement
, • , , Green Roof [ ) Cistern
!!!•• «L V I J
Figure 3A3-6. Actual site and onsite control measures (Portland, OR).
Chapter 3. Urban and Suburban
3-317
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
Table 3A3-9. Estimated sizes of on-site control measures for Scenario #4 (Portland, OR)
Total Area (acres)
Estimated Imperviousness (%)
95th percentile Rainfall Event (inches)
Expected Runoff for the 95th Percentile Rainfall Event (inches)
Stormwater Management Area Required
Paver block area estimated by Direct Determination (acres)
Bioretention estimated by Direct Determination (acres)
Green Roof estimated by Direct Determination (acres)
Cistern volume estimated by Direct Determination (gallons)
Off-site storage necessary to control the 1 0-
yr event of 3.7 inches (acre-ft)
With on-site controls
Without on-site
controls
27
95%
1.00
0.86
Hydrologic Soil Group
B
1.4
C
3.5*
0.4
1.7
50,000
5.37
7.70
5.62
7.71
The size of porous pavement area was increased because the other control options were maximized based on the site-
specific design assumptions.
A total of 1.3 acres of the site is pervious area or landscaped of which, 0.4 acres (30% of the
pervious area) could be converted to bioretention cells that have a storage depth of 10 inches.
Of the 8.8 acres of current rooftop area, 1.7 acres (20% of the rooftop area) could be retrofitted
into green roof areas. Of the 16.9 acres of paved area, 1.4 acres (8% of the paved area) for
hydrologic soil group B, or 3.5 acres (20% of the paved area) for hydrologic soil group C, of
paver block systems could be implemented. One or more cisterns (as indicated in Figure 3A3-6)
could be used to capture up to 50,000 gallons of runoff from rooftop areas. Note: The high
percentage of imperviousness of the site (95%) requires that all infiltration designs be based on
resident soil type and design volumes, or with adequate sub-bases or amended soils.
3-318
Chapter 3. Urban and Suburban
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
Scenario #5 - Near Phoenix, Arizona
A 2-acre site with 47% impervious area was selected near Phoenix, Arizona (Figure 3A3-7). If
the 95th percentile rainfall event (1.0 inches) occurred on the existing site (i.e., with no control
measures), 0.42 inches of runoff would be generated and require management. The runoff from
the 95th percentile rainfall event could be retained by installing bioretention systems totaling 0.06
acres if the hydrologic soil group B is present or 0.1 acres if hydrologic soil group C (Table
3A3-10) is the predominant soil type on the site. Assuming that bioretention practices are only
placed in areas that are currently pervious or landscaped, a total of 1.1 acres of pervious area is
available for the placement of these practices. The design storage depth of media within the
designated bioretention area was 6 inches. Note: If the design storage depth were increased to
10 inches, the off-site storage necessary for the 10-year event could be reduced to 0.03 acre-ft
for type B soils and 0.08 acre-ft for type C soils.
Figure 3A3-7. Actual site and on-site control measures (Phoenix, AZ).
Chapter 3. Urban and Suburban
3-319
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
Table 3A3-10. Estimated sizes of on-site control measures for Scenario #5 (Phoenix, AZ)
Total Area (acres)
Estimated Imperviousness (%)
95th Percentile Rainfall Event (inches)
Expected Runoff for the 95th Percentile Rainfall Event (inches)
Stormwater Management Area Required
Bioretention estimated by the Direct Determination (acres)
Off-site storage necessary to control the
10-yr event of 2.4 inches (acre-ft)
With on-site controls
Without on-site controls
2
47%
1.00
0.42
Hydrologic Soil Group
B
0.06
0.05
0.18
C
0.1
0.12
0.18
3-320
Chapter 3. Urban and Suburban
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
Scenario #6 - Boston, Massachusetts
A 3.5-acre site with 69% impervious area was selected in Boston, Massachusetts (Figure 3A3-
8). If the 95th percentile rainfall event (1.52 inches) occurred on the existing site (i.e., with no
control measures), 0.98 inches of runoff would be generated and require management. Given
these site characteristics, there is adequate area to place appropriately sized bioretention cells
to capture the 95th percentile storm event. However, for the purposes of this analysis,
unspecified conditions preclude the use of bioretention. As a result, a paver block system was
selected as the best on-site control measure and the system was designed such that the
necessary design parameters could be achieved by storing some of the volume in the paver
media and by infiltrating the remainder of the volume. The runoff from the 95th percentile rainfall
event could be retained by installing a paver block area totaling 0.4 and 0.8 acres assuming soil
types B and C, respectively (Table 3A3-11). For the purposes of this case study, a total of 1.5
acres of parking lot was made available to accommodate the paver block system. The area
retrofitted with paver blocks would primarily be dedicated for use as parking stalls.
Figure 3A3-8. Actual site and on-site control measures (Boston, MA).
Chapter 3. Urban and Suburban
3-321
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
Table 3A3-11. Estimated sizes of on-site control measures for Scenario #6 (Boston, MA)
Total Area (acres)
Estimated Imperviousness (%)
95th Percentile Rainfall Event (inches)
Expected Runoff for the 95th Percentile
Rainfall Event (inches)
Stormwater Management Area Required
Paver block area estimated by Direct Determination (acres)
Off-site storage necessary to control
10-yr event of 4.5 inches (acre-ft)
With on-site controls
Without on-site controls
3.5
69%
1.52
0.98
Hydrologic Soil Group
B
0.4
0.59
0.89
C
0.8
0.71
0.96
3-322
Chapter 3. Urban and Suburban
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
Scenario #7 - Atlanta, Georgia
A 21-acre site with 70% impervious area was selected in Atlanta, Georgia (Figure 3A3-9). If the
95th percentile rainfall event (1.77 inches) occurred on the existing site (i.e., with no control
measures), 1.17 inches of runoff would be generated and require management. The runoff from
the 95th percentile rainfall event could not be adequately retained solely with bioretention
systems. Based on the technical considerations of constructing and maintaining control
measures at the site, it was assumed that up to 15% of the pervious area could be converted
into bioretention cells and up to 40% of paved area could be converted into a paver block
system. If the stormwater management techniques used on the site includes both bioretention
and paver blocks as presented in Table 3A3-12, then all runoff for the 95th percentile rainfall
event would be controlled.
Porous Pavement
^••^^•^••l-t •*
Figure 3A3-9. Actual site and on-site control measures (Atlanta, GA).
Chapter 3. Urban and Suburban
3-323
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
Table 3A3-12. Estimated sizes of on-site control measures for Scenario #7 (Atlanta, GA)
Total Area (acres)
Estimated Imperviousness (%)
95th Percentile Rainfall Event (inches)
Expected Runoff for the 95th Percentile Rainfall Event (inches)
Stormwater Management Area Required
Bioretention estimated by the Direct Determination (acres)
Paver block area estimated by the Direct Determination (acres)
Bioretention estimated by TR-55
Paver block area estimated by TR-55
Off-site storage necessary to control 1 0-
yr event of 6.0 inches (acre-ft)
With on-site controls
Without on-site controls
21
70%
1.77
1.17
Hydrologic Soil Group
B C
0.9
0.9 3.2*
0.8** 0.9
0** 1 .84
5.85 6.62
7.25 8.49
The size of porous pavement was increased because the bioretention already reached its maximum size based on the
site-specific design assumptions.
"""Because TR-55 estimated smaller runoff in this scenario, bioretention can retain all of the 95th percentile runoff if the site
has soil group B.
For the example site in Atlanta, Georgia, areas of 1.8 acres for hydrologic soil group B, and 4.1
acres for hydrologic soil group C, would be required to manage the runoff discharged from a
95th percentile rainfall event. Assuming that bioretention practices are only placed in areas that
are currently pervious or landscaped, a total of 6.2 acres of pervious area is available for the
placement of bioretention systems. The design storage depth of media within the designated
bioretention area was 10 inches. Permeable pavement systems could be used to treat the
remaining volume on the 10.8 acres of existing paved area.
In applying the TR-55 model, the overall curve numbers for the site were 87 and 91 for Group B
and C soils, respectively. TR-55 was used to estimate 0.73 inches of runoff for soil group B and
0.97 inches for soil group C, which are smaller numbers than the 1.17 inches of runoff estimated
by the Direct Determination method. As a result, the sizes of the on-site control measures
designed using the TR-55 model were smaller than those designed using the Direct
Determination method. Note: It is recommended that caution be exercised when using TR-55 to
model storms less than 0.5 inches per event. See application of TR-55 in Table 3A3-4.
Cost estimates were also developed for this scenario (Table 3A3-13) to compare the costs to
install on-site control measures to retain the 95th percentile rainfall event, and costs to install
traditional stormwater management controls (e.g., primarily curb and gutter with off-site
retention). The cost estimates were developed for Hydrologic Soil Group B.
3-324
Chapter 3. Urban and Suburban
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
Table 3A3-13. Estimated costs for Scenario #7 (Atlanta, GA)
Sizes of on-site control practices
Rainfall depth
(in)
Bioretention (acres)
Paver blocks (acres)
Off-site Pond
WQV (ac-ft)
10-Yr Fid Cntr (ac-ft)
Total Off-Site Requirement (ac-ft)
Land Area (assumes avg 3 ft depth)
% of the site
Controls for 95th Percentile
Event
1.77
0.94
0.86
~
0.84
0.84
0.28
8.5%
Traditional Stormwater
Controls
1.75
0.0
1.75
0.58
Costs of on-site control practices
Biorention/alternative
Paver block/alternative
Off-site Pond
Infrastructure
WQV (ac-ft)
10-Yr Fid Cntr (ac-ft)
Pipe
Inlet
Land Area (assumes $300K/acre)
Sum
% difference from Traditional
$232,923
$236,878
$0
$39,648
$54,827
$52,080
$84,000
$700,356
9.9%
$30,617
$88,409
$72,888
$0
$191,095
$79,360
$175,000
$637,368
Chapter 3. Urban and Suburban
3-325
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
Scenario #8 - Cincinnati, Ohio
A 19-acre site with 51% impervious area was selected in Cincinnati, Ohio (Figure 3A3-10). If the
95th percentile rainfall event (1.45 inches) occurred on the existing site (i.e., with no control
measures), 0.68 inches of runoff would be generated and require management. The runoff from
the 95th percentile rainfall event could be retained by the installation of bioretention systems
totaling 0.8 acres if the hydrologic soil group B is present or 1.3 acres if hydrologic soil group C
(Table 3A3-8) is the predominant soil type on the site. Assuming that bioretention practices are
only placed in areas that are currently pervious or landscaped, a total of 9.4 acres of pervious
area is available for the placement of bioretention systems. The design storage depth of media
within the designated bioretention area was 8 inches.
Scenario #8 represents an alternative to the Cincinnati, scenario in #3 (Figure 3A3-5). In this
case, hydrologic soil group D was selected to represent the soil characteristics present for the
entire site. Alternatively, simulations could have been run under the assumption that the use of
infiltration practices were precluded by contaminated soils or high ground water tables. Under
these site conditions, bioretention options are severely limited and cannot be used to
adequately capture the entire 95th percentile storm event. As a result, options such as cisterns
and green roofs were considered. In the absence of management practices, the 95th percentile
rainfall event discharges 1.45 inches of stormwater and 0.53 inches of this runoff is captured by
on-site depression storage. The difference, 0.92 inches of runoff, would then require capture
and management. Based on the technical considerations of constructing and maintaining
controls at the site, it was assumed that up to 20% of pervious area can be converted into
bioretention areas; up to 30% of paved area can be converted into porous pavement; and up to
30% of the rooftop area can be converted into green roofs. Cisterns can be added to the system
if additional storage volume is required. It should be noted that green roofs were selected lowest
in the hierarchy of practices evaluated because of cost and potential structural issues
associated with design and placement on existing buildings. By using the four on-site control
options as presented in Table 3A3-14, all runoff for the 95th percentile rainfall event would be
retained. From a management perspective, it was assumed that the design storage depth within
the designated bioretention area was 6 inches because of the low infiltration rates adopted for
this scenario.
This site contains a total of 9.4 acres of pervious area, 8.0 acres of paved area, and 1.6 acres of
rooftop area. If 1.9 acres (20%) of the pervious area were converted to bioretention cells;
2.4 acres (30%) of parking lot converted to paver blocks; and 0.5 acres (30%) of rooftop area
were retrofitted to green roof areas for this site, then 97% of stormwater runoff from the 95th
percentile storm would be captured on site. By also adding one or more cisterns (as indicated in
Figure 3A3-10), an additional 13,000 gallons could be captured, thus illustrating that 100% of
the rainfall from the 95th percentile event can be managed on-site with GI/LID practices.
3-326 Chapter 3. Urban and Suburban
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
Porous Pavement [ 1 Cistern .-„„ ~-
Figure 3A3-10. Actual site and on-site control measures (Cincinnati, OH).
Table 3A3-14. Estimated sizes of on-site control measures for Scenario #8 (Cincinnati, OH)
Total Area (acres)
Estimated Imperviousness (%)
95th Percentile Rainfall Event (inches)
Expected Runoff for the 95th Percentile Rainfall Event (inches)
Stormwater Management Applied
Bioretention estimated by Direct Determination (acres)
Paver block area estimated by Direct Determination (acres)
Green Roof estimated by Direct Determination (acres)
Cisterns estimated by Direct Determination (gallons)
19
51%
1.45
0.92
Hydrologic Soil Group D
1.9
2.4
0.5
13,000
Chapter 3. Urban and Suburban
3-327
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
A 1.6 acre site with 91% impervious area was selected from Norfolk, Virginia. Table 3A3-15
contains the land use categories for the site. Figures 3A3-11 and 3A3-12 depicts the site and
associated facilities. Site specific factors based on an METF analysis allow management of 75%
of the 95th percentile storm on-site (1.27 inches). The remaining portion of the 95th percentile
rainfall event (0.41 inches would be discharged off of the site.
Table 3A3-15. Land use determination after redevelopment
Land use
Building
Parking
Streets/Sidewalks
Undeveloped
Total
Acres
0.90
0.35
0.20
0.15
1.60
Site coverage percent
56.3
21.9
12.5
9.3
100%
SHEETS:
CS10l,CGlfl1.CUl01
SHEETS:
CS102.CG102.CUI02
B4V _,
SHEETS:
CS10S,
CG105,
GUI05 -•'
Figure 3A3-11. Proposed redevelopment scenario.
3-328
Chapter 3. Urban and Suburban
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
Norfolk Naval
Avialicxi Depot
Fleet
Recreation
Park
Naval Station
Norfolk
Norfolk
Naval Station
Figure 3A3-12. Location of facility (Norfolk, VA).
Site conditions and intended uses limited the number of practices that were technically feasible
to use on-site to manage runoff. For example, the use of a green roof was not feasible because
the project includes the construction of an airplane hanger which lacks the structural strength to
support a green roof. Cisterns were also not included in the set of suitable practices based on
the analysis, which considered the number of people and amount of daily water use at the site,
i.e., 40 people x 3.5 toilet flushes per day would use only 280 gallons of runoff per day or 2,000
gallons per week. Stormwater use for HVAC make-up would also be negligible based on the
typical cooling system design. To put things in perspective, if the hanger rooftop covers the
entire building footprint, 41,000 gallons of runoff would be generated from a 1.68 inch rainfall.
Assuming a drawdown of 2,000 gallons per week based on toilet flushing, the users would only
use 5% of the 95th percentile event. Because of the relatively large volume of water that would
need to be collected and used, cisterns were not considered a feasible option to manage a
significant volume of runoff at the site.
However, site conditions did allow for the use of both permeable pavement and bioretention
practices (Figure 3A3-13 and Table 3A3-16). Approximately 0.15 acres (6,500 sf) of the
proposed site is undeveloped and available for bioretention. Based on Department of Defense
facility requirements, ten percent of the parking area is designed with landscaping, usually
Chapter 3. Urban and Suburban
3-329
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
around the perimeter and in landscaped islands. If this ten percent were designed as
bioretention cells, then 0.035 acres of bioretention would be achieved. If bioretention cells were
also placed in about 30% of the undeveloped area of the project, then an additional 0.045 acres
of bioretention could be implemented. Note: not all undeveloped land was assumed to be
available for bioretention because of conflicts with site utilities, security and anti-terrorism
requirements and slopes that limited the use of infiltration practices directly adjacent to the
hanger.
ED Bio-retention ( ] Porous Pavement
Actual site and on-site control measures (Norfolk, VA).
Table 3A3-16. Estimated sizes of on-site control measures for Scenario #9 (Norfolk, VA)
Total Area (acres)
Estimated Imperviousness (%)
95th Percentile Rainfall Event (inches)
Expected Runoff for the 95th Percentile Rainfall Event (inches)
Stormwater Management Area Required
Porous Pavement estimated by Direct
Bioretention estimated by Direct
Determination method (acres)
Determination method (acres)
1.6
91%
1.68
1.50
Hydrologic Soil Group D
0.21
0.08
3-330
Chapter 3. Urban and Suburban
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
The bioretention cells were designed with an effective storage depth of 10 inches, which
included a depth from media surface to outlet of 10 inches. In this case study, state regulations
precluded the project from taking credit for the storage potential provided by the void space
within the bioretention cell media. Similarly, approximately 0.55 acres of the proposed site is
impervious due to parking lots, streets, and sidewalks. Due to manufacturer's recommendations
that permeable pavement materials not be used in applications subject to heavy loads and
potential pollutant exposure the access roads and parking lot access isles were assumed to be
constructed from conventional impervious concrete or asphalt. Thus 60% of the parking area
(primarily parking stalls and sidewalks), which is about 38% of the entire paved area, is
assumed to be suitable for paver blocks. A high water table at the site limited the modeled net
storage depth under paver blocks placed in the parking areas and sidewalks to four inches. This
storage was calculated using the assumption that the pavement sub-base of 12 inches would
have a minimum void space of approximately 30%.
Chapter 3. Urban and Suburban 3-331
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
Comparison of the Runoff Estimation Methods
As illustrated in each of the case studies above, runoff of the 95th percentile storm was
estimated to size on-site control measures. The estimates were produced by applying four
different methods: the Direct Determination method, the Rational method, the NRCS TR-55, and
the EPA SWMM. The results comparing each of these methods for scenarios 1 through 7 are
presented in Tables 3A3-17 and 3A3-18.
Table 3A3-17. Comparison of the estimated runoff (unit: inches)
Method
Soil Groups
1
2
3
4
5
6
7
Charleston, WV
Denver, CO
Cincinnati, OH
Portland, OR
Phoenix, AZ
Boston, MA
Atlanta, GA
Direct
determination
B
0.82
0.53
0.68
0.86
0.42
0.98
1.17
C
0.82
0.53
0.68
0.86
0.42
0.98
1.17
Rational method
B
0.83
0.57
0.73
0.86
0.46
0.99
1.17
C
0.84
0.59
0.76
0.86
0.48
1.00
1.19
TR-55
B
0.36
0.12
0.26
0.63
0.06
0.51
0.73
C
0.53
0.26
0.46
0.71
0.17
0.70
0.97
SWMM
B
0.82
0.53
1.19
C
0.83
0.53
1.23
As shown in the above table, the estimated runoff results from direct determination, the Rational
Method, and SWMM are relatively similar. Runoff volumes using TR-55 are lower than the other
estimates. SWMM modeling results using NRCS 24-hour rainfall distributions were nearly
identical to the results based on uniform distribution.
Table 3A3-18. Applicability of the methods for analyzing on-site control measures
Purpose
Planning Tool
Preliminary Design
Detailed Design
Actual Assessment (Long-term)
Water Quality
Direct
determination
Applicable
Applicable
Not applicable
Not applicable
Not applicable
Rational method
Applicable
Applicable
Not applicable
Not applicable
Not applicable
TR-55*
Applicable
Applicable
Not applicable
Not applicable
Not applicable
SWMM
Applicable
Applicable
Applicable
Applicable
Applicable
*Use with caution when applying this method for small storms
3-332
Chapter 3. Urban and Suburban
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
Conclusions
Although sites varied in terms of climate and soil conditions, in most of the scenarios selected,
the 95th percentile storm event could be managed on-site with GI/LID systems. There are other
infiltration, evapotranspiration and capture and use stormwater management options available
than those used in these analyses. These options provide site managers additional flexibility to
choose appropriate systems and practices to manage site runoff.
Chapter 3. Urban and Suburban 3-333
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
References
Booth, Derek. Direct Testimony. 2008. Pollution Control Hearings Board for the State of
Washington, Puget Soundkeeper Alliance and People for Puget Sound; Pierce County
Public Works and Utilities Department; City of Tacoma; The Port of Seattle; Snohomish
County; Clark County; and Pacificorp and Puget Sound Energy, Appellants, vs.
Department of Ecology, Respondent, and King County; City of Seattle; Port of Tacoma,
and Washington State Department of Transportation, Intervenors, August 2008.
California Department of Transportation (Caltrans). 2003. Caltrans Storm Water Quality
Handbooks. California Department of Transportation.
Casey Trees. 2007. The Case for Trees - Relief from Summer Heat,
www. caseytrees.org/resources/casefortrees. htm I.
Galli, J. 1991. Thermal Impacts Associated with Urbanization and Stormwater Best
Management Practices in Maryland, Anacostia Restoration Team for the Maryland
Department of the Environment, Washington, DC.
Grant, G., L. Engleback, and B. Nicholson. 2003. Green Roofs: Their Existing Status and
Potential for Conserving Biodiversity in Urban Areas, Report Number 498, English Nature
Research Reports.
Hathaway, J., and W.F. Hunt. 2007. Stormwater BMP Costs. North Carolina Department of
Environment and Natural Resources.
www.bae.ncsu.edu/stormwater/PublicationFiles/DSWC.BMPcosts.2007.pdf.
Hirschman, D., and J. Kosco. 2008. Managing Stormwater in Your Community: A Guide for
Building an Effective Post-Construction Program, Center for Watershed Protection,
www.cwp.org/postconstruction.
Holz, T. Written Direct Testimony. 2008. Pollution Control Hearings Board for the State of
Washington, Puget Soundkeeper Alliance and People for Puget Sound; Pierce County
Public Works and Utilities Department; City of Tacoma; The Port of Seattle; Snohomish
County; Clark County; and Pacificorp and Puget Sound Energy, Appellants, vs.
Department of Ecology, Respondent, and King County; City of Seattle; Port of Tacoma,
and Washington State Department of Transportation, Intervenors, August 2008.
Horner, Richard Direct Testimony. 2008. Pollution Control Hearings Board for the State of
Washington, Puget Soundkeeper Alliance and People for Puget Sound; Pierce County
Public Works and Utilities Department; City of Tacoma; The Port of Seattle; Snohomish
County; Clark County; and Pacificorp and Puget Sound Energy, Appellants, vs.
Department of Ecology, Respondent, and King County; City of Seattle; Port of Tacoma,
and Washington State Department of Transportation, Intervenors, August 2008.
3-334 Chapter 3. Urban and Suburban
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
National Climatic Data Center (NCDC). 2007. NCDC precipitation data, CD-ROM, National
Climatic Data Center.
National Research Council. 2008. Urban Stormwater Management in the United States, The
National Academies Press, Washington, DC.
Shaver, E., R. Horner, J. Skupien, C. May, and G. Ridley. 2007. Fundamentals of Urban Runoff
Management: Technical and Institutional Issues. 2nd ed. North American Lake
Management Society, Madison, Wl.
Schueler, T. and M. Helfrich. 1988. Design of Wet Extended Detention Pond Systems. Design
of Urban Runoff Controls, L. Roesner and B. Urbonas eds., American Society of Civil
Engineers, New York, NY.
Schueler, T., and H. Holland. 2000. The Practice of Watershed Protection: Techniques for
Protecting our Nation's Streams, Lakes, Rivers, and Estuaries. Center for Watershed
Protection, Ellicott City, MD.
U.S. Department of Agriculture, Natural Resources Conservation Service. 2007. National
Engineering Handbook, title 210-VI. Part 630, chapter 7. Washington, DC.
http://directives.sc.egov.usda.gov.
U.S. Department of Agriculture, Soil Conservation Service. 1986. Urban Hydrology for Small
Watersheds. Technical Release No. 55. Second Edition. Washington, D.C.
U.S. Environmental Protection Agency, Managing Wet Weather with Green Infrastructure,
www.epa.gov/greeninfrastructure.
Vingarzan and Taylor. 2003. Trend Analysis of Ground Level Ozone in the Greater Vancouver/
Fraser Valley Area of British Columbia, Environment Canada -Aquatic and Atmospheric
Sciences Division.
Wsconsin DNR. 2008. Impact of Redevelopment on TSS Loads, Runoff Management, available at
http://www.dnr.state.wi.us/runoff/pdf/rules/nr151/lmpact of RedevTSSLoads 021308.pdf.
Chapter 3. Urban and Suburban 3-335
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
Resources: Runoff Methodology Parameter Assumptions
Runoff from each land cover was estimated by the following equation:
Runoff = Rainfall - Depression Storage - Infiltration Loss
(1)
Depression Storage
Reference depression storage (inches)
Reference
1
2
3
Impervious
0.05-0.1
0.01-0.11
0.1
Pervious
0.1-0.3
0.02-0.6
0.2
1. ASCE. 1992. Design & Construction of Urban Stormwater Management Systems. New York, NY.
2. Marsaleck, J., B. Jimenez-Cisreros, M. Karamouz, P.R. Malmquist, J. Goldenfum, and B. Chocat. 2007. Urban Water
Cycle Processes and Interactions. Urban Water Series, UNESCO-IMP, Tyler & Francis.
3. Walesh, S.G. 1989. Urban Surface Water Management. John Wiley & Sons, Inc.
Based on the above reference data, depression storage (or initial abstraction, the rainfall
required for the initiation of runoff) to the direct determination method was assumed as follows:
• Rooftop: 0.1 inches
• Pavement: 0.1 inches
• Pervious area: 0.2 inches
Infiltration
Infiltration loss occurs only in pervious areas. In this analysis, infiltration was estimated by
Morton's equation:
Ft - rmjn + (/max — fmjn) 6 — K t
(2)
where
Ft = infiltration rate at time t (in/hr),
fmin = minimum or saturated infiltration rate (in/hr),
fmax = maximum or initial infiltration rate (in/hr),
k = infiltration rate decay factor (/hr), and
t = time (hr) measured from time runoff first discharged into infiltration area
3-336
Chapter 3. Urban and Suburban
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
Reference infiltration parameters
Maximum infiltration rate (in.hr), fmax
Infiltration
(in/hr)
Sandy
Loam
Clay
Partially dried out with
No vegetation
2.5
1.5
0.5
Dense vegetation
5
3
1
Dry soils with
No vegetation
5
3
1
Dense vegetation
10
6
2
Reference: Huber, W. C. and R. Dickinson. 1988. Storm Water Management Model User's Manual, Version •
EPA/600/3-88/001 a (NTIS PB88-236641/AS), U.S. Environmental Protection Agency, Athens, GA.
Minimum infiltration rate (in/hr), fmin
Hydrologic Soil
Group
A
B
C
D
Infiltration (in/hr)
0.45-0.30
0.30-0.15
0.15-0.05
0.05-0
A: well drained sandy; D: poorly drained clay
Reference: Huber, W.C., and R. Dickinson. 1988. Storm Water Management Model User's Manual, Version 4. EPA/600/3-
88/001a (NTIS PB88-236641/AS), U.S. Environmental Protection Agency, Athens, GA.
Decay coefficient, k
Soils
Sandy
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
• Hydrologic Soil Group C
- Maximum infiltration rate: 3 in/hr
- Minimum infiltration rate: 0.1 in/hr
- Decay factor: 3.5 /hr
• Hydrologic Soil Group D
- Maximum infiltration rate: 1 in/hr
- Minimum infiltration rate: 0.02 in/hr
- Decay factor: 5 /hr
Infiltration loss for the 24-hr rainfall duration was estimated by the following equations with
assumptions of a half hour Af:
Infiltration Loss at the nth time-step = (f -A/) = {(/„_, + /„)/ 2) • At}
Integrated Infiltration Loss for 24 hours = £ (f • A/)
Integrating infiltration loss during 24 hours with a half hour At
(3)
(4)
time-step
0
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
t
(hr)
0
0.5
1
1.5
2
2.5
3
3.5
4
4.5
5
5.5
6
6.5
7
7.5
Infiltration rate
(in/hr)a
SoilB
5
2.03
0.94
0.53
0.39
0.33
0.31
0.30
0.3
0.3
0.3
0.3
0.3
0.3
0.3
0.3
SoilC
3
0.60
0.19
0.12
0.10
0.1
0.1
0.1
0.1
0.1
0.1
0.1
0.1
0.1
0.1
0.1
SoilD
1
0.100
0.027
0.021
0.02
0.02
0.02
0.02
0.02
0.02
0.02
0.02
0.02
0.02
0.02
0.02
Infiltration volume
(inches)15
SoilB
0
1.757
0.741
0.368
0.230
0.179
0.161
0.154
0.15
0.15
0.15
0.15
0.15
0.15
0.15
0.15
SoilC
0
0.901
0.198
0.076
0.054
0.05
0.05
0.05
0.05
0.05
0.05
0.05
0.05
0.05
0.05
0.05
SoilD
0
0.275
0.032
0.012
0.01
0.01
0.01
0.01
0.01
0.01
0.01
0.01
0.01
0.01
0.01
0.01
3-338
Chapter 3. Urban and Suburban
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
time-step
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
t
(hr)
8
8.5
9
9.5
10
10.5
11
11.5
12
12.5
13
13.5
14
14.5
15
15.5
16
16.5
17
17.5
18
18.5
19
19.5
20
20.5
21
21.5
22
22.5
23
23.5
24
Infiltration rate
(in/hr)a
SoilB
0.3
0.3
0.3
0.3
0.3
0.3
0.3
0.3
0.3
0.3
0.3
0.3
0.3
0.3
0.3
0.3
0.3
0.3
0.3
0.3
0.3
0.3
0.3
0.3
0.3
0.3
0.3
0.3
0.3
0.3
0.3
0.3
0.3
SoilC
0.1
0.1
0.1
0.1
0.1
0.1
0.1
0.1
0.1
0.1
0.1
0.1
0.1
0.1
0.1
0.1
0.1
0.1
0.1
0.1
0.1
0.1
0.1
0.1
0.1
0.1
0.1
0.1
0.1
0.1
0.1
0.1
0.1
SoilD
0.02
0.02
0.02
0.02
0.02
0.02
0.02
0.02
0.02
0.02
0.02
0.02
0.02
0.02
0.02
0.02
0.02
0.02
0.02
0.02
0.02
0.02
0.02
0.02
0.02
0.02
0.02
0.02
0.02
0.02
0.02
0.02
0.02
Sum: Infiltration loss during 24 hours c
Infiltration volume
(inches)15
SoilB
0.15
0.15
0.15
0.15
0.15
0.15
0.15
0.15
0.15
0.15
0.15
0.15
0.15
0.15
0.15
0.15
0.15
0.15
0.15
0.15
0.15
0.15
0.15
0.15
0.15
0.15
0.15
0.15
0.15
0.15
0.15
0.15
0.15
9.743
SoilC
0.05
0.05
0.05
0.05
0.05
0.05
0.05
0.05
0.05
0.05
0.05
0.05
0.05
0.05
0.05
0.05
0.05
0.05
0.05
0.05
0.05
0.05
0.05
0.05
0.05
0.05
0.05
0.05
0.05
0.05
0.05
0.05
0.05
3.430
SoilD
0.01
0.01
0.01
0.01
0.01
0.01
0.01
0.01
0.01
0.01
0.01
0.01
0.01
0.01
0.01
0.01
0.01
0.01
0.01
0.01
0.01
0.01
0.01
0.01
0.01
0.01
0.01
0.01
0.01
0.01
0.01
0.01
0.01
0.769
a Calculated infiltration rate at each time by Equation (2)
b Calculated infiltration volume from the previous time to the current time by Equation (3)
c Integrated infiltration volume for 24 hours with a half hour At by Equation (4)
Chapter 3. Urban and Suburban
3-339
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
Based on the above calculation, 24-hr infiltration losses for pervious areas and bioretention
areas were modeled as follows:
• Soil Group B: 9.743 inches
• Soil Group C: 4.430 inches
• Soil Group D: 0.769 inches
Infiltrations of underlying soils at paver blocks were modeled conservatively by applying the
minimum infiltration rate for each soil type (Infiltration loss = fmin • 24) because the soils under
the paver blocks may require or be subjected to some compaction for engineering stability. The
estimated infiltration losses for each soil are presented below:
• Soil Group B: (0.3 in/hr) • (24 hrs) = 7.2 inches
• Soil Group C: (0.1 in/hr) • (24 hrs) = 2.4 inches
• Soil Group D: (0.02 in/hr) • (24 hrs) = 0.48 inches
Design Storage of Management Practices
Bioretention
Reference
1
2
3
4
5
6
Ponding
(inches)1
up to 12
6-12
6-12
up to 6
6-18
Mulch
(inches)
2-4
(optional)
2-3
2-3
as needed
Soil media
(ft)
1-1.5
2.5-4
2-4
1.5-4
1.5-2
2-4
Soil media
porosity
about 40%
about 40%
30%-40%
Underdrain
bioretention systems utilize
infiltration rather than an underdrain
recommended, especially if initial
testing infiltration rate < 0.52 in/hr
if necessary
Optional
if necessary
1. State of New Jersey. 2004. New Jersey Stormwater Best Management Practices Manual
www.ni.aov/dep/stormwater/tier A/pdf/NJ SWBMP 9.1 print.pdf.
2. MDE (Maryland Department of the Environment). 2000. 2000 Maryland Stormwater Design Manual, Volumes I & II,
prepared by the Center for Watershed Protection and the Maryland Department of the Environment, Water Management
Administration, Baltimore, MD.
www.mde.state.md.us/Proarams/WaterProarams/SedimentandStormwater/stormwater design/index.asp.
3. Clar, M.L., and R. Green. 1993. Design Manual for Use of Bioretention in Storm Water Management, prepared for the
Department of Environmental Resources, Watershed Protection Branch, Prince George's County, MD, by Engineering
Technologies Associates, Inc. Ellicott City, MD, and Biohabitats, Inc., Towson, MD.
4. USEPA(U.S. Environmental Protection Agency). 1999. Storm Water Technology Fact Sheet: Bioretention. EPA 832-F-
99-012. Office of Water. US Environmental Protection Agency. Washington, D.C. www.epa.gov/owm/mtb/biortn.pdf.
1 Ponding is a measure of retention capacity
3-340
Chapter 3. Urban and Suburban
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
5. Prince George's County. Bioretention Design Specifications and Criteria. Prince George's County, MD.
www.co.pa.md.us/Government/Agencvlndex/DER/ESG/Bioretention/pdf/bioretention design manual.pdf.
6. City of Indianapolis. 2008. Indianapolis Stormwater Design Manual.
www.sustainindv.org/assets/uploads/4 05 Bioretention.pdf.
Paver Blocks
Reference
1
2
3
Media
(inches)
12 or more
9 or more
12-36
Void space
40%
40%
40%
1. University of California at Davis. 2008. Low Impact Development Techniques: Pervious Pavement.
http://extension.ucdavis.edu/unit/center for water and land use/pervious pavement.asp.
2. AMEC Earth and Environmental, Center for Watershed Protection, Debo and Associates, Jordan Jones and Goulding,
and Atlanta Regional Commission. 2001. Georgia Stormwater Management Manual Volume 2: Technical Handbook
www.aeoraiastormwater.com/.
3. Subsurface Infiltration Bed. www.tredvffrin.ora/pdf/publicworks/CH2 - BMP4 Infiltration Bed.pdf.
Green Roofs
Reference
1
2
3
Media
(inches)
3-4
1-6
2-6
1. Charlie Miller. 2008. Extensive Green Roofs. Whole Building Design Guide (WBDG).
www.wbda.ora/resources/greenroofs.php.
2. Great Lakes WATER Institute. Green Roof Project: Green Roof Installation.
www.alwi.uwm.edu/research/aenomics/ecoli/greenroof/roofinstall.php.
3. Paladino & Company. 2004. Green Roof Feasibility Review. King County Office Project.
http://vour.kinacountv.aov/solidwaste/areenbuildina/documents/KCGreenRoofStudv Final.pdf.
Based on the above reference data, design storages to the direct determination method were
assumed as follows:
• Bioretention: up to 10 inches (depending on practice used, site conditions, and the like)
• Green roof: 1 inch (2.5 inches deep media with 40% void space)
• Porous pavement: 4 inches (10 inches deep media with 40% void space)
Factors that influence total storage available include, ponding depth, available media void
space, and supplemental storage if the system is designed with gravel or open pipes
underneath the media.
Chapter 3. Urban and Suburban
3-341
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
Chapter 4.
Forestry
Contents
1 Nonpoint Source Pollution and the Chesapeake Bay: Forests in Perspective 4-2
2 Forestry Practices for Water Quality Protection 4-8
2.1 Introduction 4-8
2.2 Preharvest Planning 4-11
2.3 Streamside Management Areas (SMAs) 4-17
2.4 Forest Road Construction/Reconstruction and Forest Road Management 4-22
2.5 Timber Harvesting 4-29
2.6 Site Preparation 4-31
2.7 Fire Management 4-32
2.8 Revegetation of Disturbed Areas 4-34
2.9 Forest Chemical Management 4-35
2.10 Wetlands Forest Management 4-35
3 References 4-37
Chapter 4. Forestry 4-1
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
1 Nonpoint Source Pollution and the Chesapeake
Bay: Forests in Perspective
The Chesapeake Bay Program has published a report on the health of the Chesapeake Bay
almost annually since 1999 (CBP 2009a). In that report the program provides information on the
primary sources of nitrogen (N), phosphorus (P), and sediment—the pollutants of most concern
in the Chesapeake Bay. The list of largest contributors of nutrients to the Bay in the annual
reports invariably has included agriculture, atmospheric deposition, wastewater, and
urban/suburban lands. The 2007 report also includes septic systems as a primary contributor.
Of the states in the Chesapeake Bay watershed, only Virginia notes silviculture as a source
contributing to water quality impairment. Virginia lists silviculture as a probable source of
impairment for 14.8 miles of rivers and streams, or 0.069 percent of the total river and stream
miles reported (USEPA 2008). Silviculture was not listed as a source of impairment to any other
waterbody types.
Forest harvesting and other silvicultural activities, therefore, are generally not identified in state
reports as having a significant adverse effect on the Chesapeake Bay. Forests play an
important role in helping to protect water quality in the Bay. Some excerpts from the reports
about the importance of forests in the Chesapeake Bay are provided below.
• Forests protect and filter drinking water for 75 percent of the Bay watershed's residents
and provide valuable ecological services and economic benefits including carbon
sequestration, flood control, wildlife habitat and forest products. Retaining and
expanding forests in the Chesapeake Bay watershed is critical to our success in
restoring the Chesapeake Bay. Forests are the most beneficial land use for protecting
water quality, due to their ability to capture, filter and retain water, as well as absorb
pollution from the air (CBP 2008).
• In addition to preserving the watershed, well-maintained forest buffers naturally absorb
nutrients and sediments, thus improving water quality in neighboring streams. Riparian
forest buffers also provide a source of large, woody material input to streams that helps
form and maintain important fish habitat and provide for channel stability (CBP 2008).
• Scientific findings clearly show that well-managed forests are the most beneficial land
use for clean water. Experts agree that healthy forests are directly linked to the health of
rivers in the Chesapeake Bay watershed and, ultimately, the Bay. Large areas of healthy
forest and streamside forests are essential to keeping nutrient and sediment pollution
out of the rivers and Bay (CBP 1999).
4-2 Chapter 4. Forestry
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
A relatively new EPA initiative—the Healthy Watersheds Initiative—augments the Agency's well-
established watershed approach with proactive, holistic, aquatic ecosystem conservation and
protection. EPA recognizes the numerous benefits that healthy watersheds provide. For
instance, forested watersheds protect aquifer recharge zones and surface water sources and
reduce water treatment costs: For every 10 percent increase in forest cover in an aquifer's
source area, chemical and treatment costs decrease by 20 percent. Healthy watersheds also
provide benefits like habitat for fish, amphibians, birds, and insects; recreational opportunities
such as fishing, water-based recreation, and tourism; and vast carbon storage capabilities.
Healthy watersheds are also less vulnerable to floods, fires, and other natural disasters, which
reduces costs to communities.
The Healthy Watersheds Initiative includes both assessment and management approaches that
encourage states, local governments, watershed organizations, and others to take a strategic,
systems approach to conserve healthy components of watersheds. The initiative combines
understanding of the biological, chemical, and physical condition of waterbodies with watershed
functional attributes, such as hydroecology, geomorphology, and natural disturbance patterns
and, thus, helps us manage watersheds as integrated systems that can be understood through
the dynamics of essential ecological attributes.
Forested watersheds are well recognized to provide water quality benefits. The full suite of the
economic values of forested watersheds is difficult to quantify, however. Forest cover intercepts
rainfall, protecting soils from erosion; the roots of trees and forest litter covering a forest floor
prevent soil erosion; trees absorb water, delaying the input of stormwater runoff to streams; and
forest vegetation absorbs nutrients that could otherwise be lost to surface waters through
surface runoff and groundwater. All these water quality services provided by forests are
valuable to society, but their dollar value varies by the location of the forest (e.g., Is it in a
watershed that provides municipal drinking water?), species and sizes of trees, condition of the
forest, climate, rainfall characteristics, and soil characteristics (e.g., erodibility, nutrient content)
(CWP no date). The water quality protection service of an acre of forest, therefore, cannot be
assigned a single dollar value. Studies have estimated the value of forest conservation
(Table 4-1), resulting in a range of $25 million to $6 billion of capital costs that have been
avoided through watershed protection.
Chapter 4. Forestry 4-3
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
Table 4-1. Avoided costs of constructing filtration plants through watershed protection
Metropolitan area
New York City, NY
Boston, MA
Seattle, WA
Portland, OR
Portland, ME
Syracuse, NY
Auburn, ME
Avoided costs
$1 .5 billion spent on watershed protection over 10 years to avoid at least $6 billion
in capital costs and $300 million in annual operating costs
$180 million (gross) avoided cost
$150-200 million (gross) avoided cost
$920,000 spent annually to protect watershed in avoiding a $200 million
cost
$729,000 spent annually to protect watershed has avoided $25 million in
costs and $725,000 in operating costs
capital
capital
$10 million watershed plan is avoiding $45-60 million in capital costs
$570,000 spent to acquire watershed land is avoiding $30 million capital
$750,000 in annual operating costs
cost and
Source: CWP No date
Forests, especially well-managed forests, are a key element in any state, local, or federal water
quality protection program. It is estimated that between 50 and 75 percent of the population of
the United States relies on forest lands for good quality water (Neary et al. 2009). Forests and
forested land—whether in a rural setting, along streams on agricultural land, intermixed with
other land uses in suburban settings, or in urban locations—possess characteristics that other
soil types do not that make them act as natural filters for stormwater and one of the least
expensive and most effective means of protecting water quality. (Further information about the
benefits of trees and forests in urban settings is provided in Chapter 3 of this guidance
[Chapter 3: Urban and Suburban]). These characteristics include high levels of organic matter
on the forest floor that intercepts rain drops, and soil porosity from root growth and decay,
cracking from freeze/thaw and wetting/drying processes, animal burrowing, and other natural
processes. Much rain water is thus stored in the forest soil and its delivery to streams is
primarily via groundwater flow; surface runoff is rare in forest settings. Good water quality is a
result of the nutrient uptake and cycling and contaminant sorption processes that occur as water
passes through the soil before reaching stream networks (Neary et al. 2009).
One strategy that states use to achieve well-managed forests is training programs for licensed
loggers. Such logger training programs are run by state departments of forestry, universities, or
nonprofit forestry groups, and they are critical to the effective use of best management practices
(BMPs) on harvest sites. The New York Logger Training is a cooperative effort of timber
harvesters, forest industry, government, educators, and foresters working together to deliver
resources that allow loggers to learn environmentally sound practices and improved skills
(NYLT 2010). The Sustainable Forestry Initiative Program in Pennsylvania has developed a
comprehensive training program for loggers. A variety of courses cover topics from basic
compliance with local, state, and federal laws; to in-depth discourses on business management,
wildlife, forest management, and ecology; BMPs for erosion control; and others (Loggertraining
4-4 Chapter 4. Forestry
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
2010). In West Virginia, the West Virginia Division of Forestry provides workshops on BMPs for
practicing loggers (WVDOF 2010). The logger training program in Virginia is referred to as the
SHARP (Sustainable Harvesting and Resource Professional). To achieve SHARP Logger
standing, participants must complete a core program of 18 hours of classroom and field training
(Virginia Tech 2010). Of those 18 hours, 6 hours cover sustainable forestry, and 6 hours are
devoted to BMPs. The Sustainable Forestry session combines classroom sessions with field
exercises. Participants review the principles of sustainable forestry, and then tour a forest site to
observe examples of forest ecology and silviculture. The Harvest Planning and Best
Management Practices session includes visiting a forested site, discussion of how to use
topographic maps, and training on the essential elements for an environmentally sound harvest
plan.
Another important development in forest management is the increasing acceptance and use of
sustainable forest management techniques through third-party forest certification programs.
Forest certification began to become established in the mid- to late-1990s and is gaining
attention, participation, and acceptance (Mercker and Hodges 2007). Forest certification
programs often offer a more robust approach to preharvest planning activities and offer a host of
economic and sustainability benefits. One of the principles of sustainable forestry is to protect
waterbodies and riparian zones and to conform to BMPs to protect water quality (SFI 2010). The
most commonly cited benefits of forest certification programs are market access, credibility, and
improved forest management. A second potential benefit from certification is assurance that
landowners are managing their property in the most sustainable way possible. A third-party
audit provides a system for validating sustainable management claims. That could assure public
agencies and the general public that the landowner is engaged in long-term forest management
(University of Florida 2007). On a per acre basis, direct costs will generally increase as
ownership size decreases and might vary from less than $1/acre to many dollars per acre
(University of Florida 2007).
As described fully in the Riparian chapter of this document, forested riparian buffers can provide
some measure of flow regulation under certain watershed conditions. A primary way in which
buffers reduce flow velocity is by creating physical barriers that slow down the flow and allow
infiltration of water into soil. They also maintain streamside soils in a condition to absorb water
by virtue of their extensive root systems and organic litter production that provide the soil
structure necessary for a large quantity of infiltration. Rainfall and runoff intensity, soil
characteristics, hydrologic regime, and slope of the buffer and runoff source area are some of
the factors that determine a forested riparian buffer's ability to regulate stream flow. A narrow
forested buffer on a steep, non-vegetated slope has little ability to regulate flow, whereas a wide
forested buffer on a gentle, vegetated slope could help reduce peak flow levels and provide for
dry season flow.
Chapter 4. Forestry 4-5
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
Leaders of the Chesapeake Bay Program clearly recognize the importance of forests and
forested riparian areas to the Bay's health. For example, the current Federal Leadership
Committee strategy is to protect 2 million acres of lands throughout the watershed currently
identified as high conservation priorities at the local, state, and federal level (including 695,000
acres of forest land of highest value for maintaining water quality) by 2025 (Federal Leadership
Committee 2010). An original goal of 2,010 miles of forest buffer restoration by 2010 was
achieved ahead of time, and a new goal to restore forests along at least 70 percent of streams
and shorelines in the Bay watershed was set in 2003. The Bay was to have at least 10,000
shoreline miles forested by 2010 (CBP 2009b). The progress as of 2009 was 6,901 miles. A
federal implementation plan was developed as part of the initiative. For federally managed
lands—approximately 1.9 million acres of the 2.2 million acres of federal lands in the
Chesapeake watershed are forested—this plan focused on protecting existing forests from
development, incorporating forest conservation into land use planning, and working with forest
landowners to promote forest conservation.
Research in N saturation shows that young forests capture more N from atmospheric inputs.
Old forests generally do not leak N unless there is a large input source of N, such as from
atmospheric pollutants (Kyker-Snowman no date). The retention of atmospheric N in forested
watersheds is directly influenced by species composition and many factors that can change that
composition, e.g., natural succession, climate change, forest management practices, forest pest
infestations (Lovett et al. 2002). Undisturbed and properly managed forested ecosystems have
considerable capacity to retain and efficiently cycle reactive N and prevent it from entering
waterways. If, however, a forested system experiences a disturbance—such as widespread
removal of vegetation—its ability to retain N is diminished. Implementing sound forest
management practices can minimize such effects (SUNY 2010).
Deforestation is the long-term conversion of forest to another land use or the long-term
reduction of the tree canopy cover below a 10 percent threshold. Chesapeake Bay Program
land analyst scientists have a very good idea where deforestation will occur in the coming years
in the Bay watershed. Forests that are vulnerable to development and that without action would
be expected to be developed are critical to protecting the Bay watershed. Preventing the loss of
those forests is referred to as avoided deforestation, and it has been used as a measure of
credit for more than 10 years.
The nutrient reduction efficiency of avoided deforestation can be considerable because of the
difference in nutrient loading to the Chesapeake Bay between a natural forest versus typical
development. Bay scientists ran a model to compare N contributions to the Bay under the
scenario that all high-value, vulnerable forests are lost versus those forests remaining protected.
The model predicted that if the forests are protected, 3.1 million pounds of N would be
prevented from flowing into the Bay.
4-6 Chapter 4. Forestry
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
The focus on forestry in the Bay is on preserving forests, maintaining forested shorelines and
streambanks, and restoring forests near Bay waters and throughout the Bay watershed where
they have been removed.
The lessons from the above-mentioned reports and initiatives—and the message to be gained
from this guidance—are the following:
• Forests and forested buffers are extremely important to maintaining and improving water
quality in the Chesapeake Bay.
• Maintaining well-managed, protective forested riparian buffers in a condition that
conserves or enhances their ability to trap pollutants; protect the water quality of the
Bay; and provide high-quality habitat for aquatic species is vitally important.
• Most forests in the Bay watershed are privately owned (approximately 80 percent)
(Blankenship 2006). The objectives and motivations of private landowners must be
considered in determining what BMPs should be recommended to successfully engage
forest owners in maintaining their forests for the future. The Chesapeake Bay Program
estimates that as much as 35 percent of the region's private forests are vulnerable to
development (CBP 2004).
Chapter 4. Forestry 4-7
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
2 Forestry Practices for Water Quality Protection
2.1 Introduction
The effects of forestry activities on surface waters are of concern because healthy, clean waters
are important for aquatic life, drinking water, and recreational use. Surface waters and their
ecology can be affected by inputs of sediment, nutrients, and chemicals, and by alterations to
stream flow that can result from forestry activities. The purpose of implementing measures and
BMPs to protect surface waters during and after forestry activities is to protect important
ecological conditions and characteristics of the surface waters in areas with roads and logged,
forested areas. Such conditions vary with waterbody type, but, in general, the ecological
conditions that implementation measures and BMPs are intended to protect include the
following:
• General water quality, by minimizing inputs of polluted runoff
• Water temperature, by ensuring an adequate amount of shade along shorelines and
streambanks
• Nutrient balance, by providing for an adequate influx of carbon and nutrients that serve
as the basis of aquatic food chains
• Habitat diversity, by ensuring that inputs of large organic debris to the aquatic system
are appropriate for the system
• Hydrologic processes, by limiting disturbances to ground cover, overland flow, and
stream flow patterns, both seasonal and annual
Logging a forested area can affect all those ecological conditions to some extent. Preharvest
conditions might consist of canopy, subcanopy, and herbaceous vegetative layers; a thick litter
layer; a complex of tree, shrub, and herbaceous roots surrounded by uncompacted soils; 70-
100 percent shade at ground level; nutrient cycling between vegetation and soils; and a
vegetation-buffered hydrologic process. Post-harvest, the canopy and subcanopy are reduced;
the litter layer is removed in some areas and compacted in others; roots of removed vegetation
decompose; sunlight penetration to the ground is increased; nutrient absorption by vegetation is
reduced; and more rainfall reaches the ground, less rain water evaporates back to the
atmosphere, and runoff increases. Those changes can lead to increased water, sediment, and
nutrient delivery to streams, but the post-harvest effects can be minimized through the use of
appropriate BMPs during and immediately after a harvest, followed by regular BMP
maintenance. Forestry activities and their potential effects on forest hydrology and water quality
(through nonpoint source pollution) are discussed below.
4-8 Chapter 4. Forestry
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
Sediment
Sediment deposited in surface waters is addressed in this document because of its potential to
affect in-stream conditions and aquatic communities. Sediment is the pollutant most associated
with forestry activities. Soil is lost from the forest floor by surface erosion following ground
disturbances typically associated with a forest harvest (e.g., use of heavy machinery, skidding,
truck traffic), or through mass wasting (e.g., landslides on steep slopes induced by loosened soil
from decomposed tree roots after a harvest).
In undisturbed forests, surface erosion generally contributes minor quantities of sediment to
streams and the quantity of surface erosion depends on factors mentioned earlier, such as soil
type, topography, and amount of vegetative cover (Spence et al. 1996).
Rill erosion and channelized flow occur where rainwater and snowmelt are concentrated by
landforms, including berms on roads and roadside ditches. They cause erosion most severely
where water is permitted to travel a long distance without interruption over steep slopes
because the combination of distance and slope tends to increase the volume and velocity of
runoff. Sheet erosion, or overland flow, occurs occasionally on exposed soils where the
conditions necessary for it exist—including saturated soil or a rainfall intensity that is greater
than the ability of soil to absorb the water—but it is not common on forest soils because the
forest floor and associated litter layer have a very high infiltration capacity.
Nutrients
Nutrients, such as N and P in soil and plant material, are primary chemical water quality
constituents. They can enter waterbodies attached to sediments, dissolved in the water, or
transported by air. Forest harvesting can locally increase nutrient leaching from the soil through
its disruption of the cycling of nutrients between the soil and overlying vegetation, although the
effect generally subsides to near precutting levels within 2 years of a harvest, provided that all
appropriate post-harvest measures are taken to revegetate the site. Excessive amounts of
nutrients can stimulate algal blooms or an overgrowth of other types of aquatic vegetation. That
can, in turn, lead to an increase in the amount of decomposing plant material in an aquatic
system and increased turbidity and biological oxygen demand. The latter effect can decrease
dissolved oxygen concentrations, with potentially detrimental effects to aquatic biota. Chapter 3,
section I (Forest Chemical Management) of EPA's 2005 guidance National Management
Measures to Control Nonpoint Sources of Pollution from Forestry (USEPA 2005), discusses
methods for minimizing the adverse effects of forestry activities on nutrient balances.
Organic debris, discussed below, can be an important source of nutrients in an aquatic
environment. Streamside Management Areas (SMAs) play an important role in organic debris
inputs and maintaining nutrient balances in aquatic forest ecosystems.
Chapter 4. Forestry 4-9
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
Organic Debris
Organic debris—primarily composed of leaves, twigs, branches, and fallen trees—is an
important element of water quality because it provides nutrients and stream structure that are
important to supporting aquatic life. The presence of organic matter in the form of woody debris
is one of the primary influences on the microbial denitrification process. It ranges in size from
suspended organic matter in water to fallen trees. Large, woody debris, or LWD, can be whole
trees or tree limbs that have fallen into streams. It contributes to the physical habitat diversity
essential to support aquatic life. As a structural element, LWD influences the movement and
storage of sediment and gravel in streams and stabilizes streambeds and banks. Small, organic
litter—primarily leaves in deciduous forests and cones and needles in coniferous forests—is an
important source of nutrients for aquatic communities. It usually decomposes over a year or
more, depending on the forest type.
When streamside vegetation is removed—especially when riparian canopy trees are removed—
inputs of organic debris decrease and the amount of sunlight reaching the water increases. For
a stream that might have relied primarily on sources of nutrients external to the stream (fallen
debris), vegetation removal can force the stream to rely primarily on in-stream sources (such as
algal growth and in-stream vegetation), which might not be present in low-order streams.
Organic debris generated during forestry activities include residual logs, slash, litter, and soil
organic matter. Such materials can perform some of the same positive functions as naturally
occurring LWD and organic litter. If their abundance in a stream is substantially greater than
normal, however, they can also block or redirect streamflow, alter nutrient balances, and
decrease the concentration of dissolved oxygen as they decompose and consume oxygen.
In 2005 EPA published National Management Measures to Control Nonpoint Sources of
Pollution from Forestry (USEPA 2005). Little has changed with respect to the commonly
accepted best practices of protecting surface waters from inputs of sediment and nutrients
during and after forestry activities since that guidance was published. The 2005 guidance was
based on a comprehensive review of both the scientific literature and state forestry practices at
the time. A review of state forestry practices and the recent literature indicates that the
information in the 2005 guidance is still as relevant today as it was when it was published.
Recent research on forest harvesting has focused on better understanding how some BMPs
work (and why they fail) and on methods that can be used to reduce the cost and effort involved
in forest planning and harvesting. One of the greatest risks to water quality from forestry
activities come from having unprotected streams. SMAs have proven to be an important
component of water quality protection in forested areas, and recent research has focused on
understanding the width requirements and vegetative and soil characteristics that give SMAs
their water-quality protection abilities.
4-10 Chapter 4. Forestry
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
The other major risk to water quality from forestry activities comes from sediment-laden runoff
from areas disturbed by forestry activities, especially roads, landings, and skid trails. Not
surprisingly, those have also been the focus of the bulk of the research over the past 5 years.
Road building and timber removal are among the most costly aspects of forest harvesting, and
much research has focused on reducing the costs of forest harvest planning, road building, and
timber removal.
Below is a review of the implementation measures from EPA's 2005 guidance, with minor
changes made to a few. Some of the implementation measures are not updated in this guidance
because the 2005 guidance adequately identifies and discusses the best practices for protecting
water quality from forestry activities. For those implementation measures that are updated, the
relevant sections below provide a brief overview of the BMP-specific guidance provided in
EPA's forestry guidance, some recommendations suggested by the recent research that could
help improve on the advice provided in the 2005 guidance, and a brief review of some recent
research relating to the recommendations.
2.2 P re harvest Planning
Implementation Measure F-1:
Perform advance planning for timber harvesting and forest road systems that includes
the following elements, where appropriate:
1. Identify the harvest area and road layout and areas to be avoided during
harvest and road construction (for example, waterbodies, wetlands, protected
species locations and habitat, and highly erosive soils). Avoid locating roads,
landings, and skid trails on steep grades and in SMAs. Use electronic and
paper topographic and soil maps and a handheld global positioning system
unit to facilitate marking the features, and mark them in a highly visible
manner before the harvest.
2. Consider all water quality-related factors when planning the harvest and road
system. Factors to consider include soil moisture conditions when the harvest
and heaviest traffic will occur, BMPs for erosion control during and after the
harvest, and existing water quality conditions in all potentially affected
waterbodies.
3. Design roads to withstand the anticipated amount of traffic during the
anticipated season of harvest such that ruts will not form and the effectiveness
of road surface drainage features will not otherwise be compromised.
Chapter 4. Forestry 4-11
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
4. Design road drainage structures to discharge runoff in small quantities to off-
road areas that are not hydrologically connected to surface waters.
5. Design the road layout to minimize the number of stream crossings.
6. For fish-bearing streams, design stream crossings to permit fish passage.
The Preharvest Planning implementation measure is to ensure that all forestry activities are
planned with water quality considerations in mind and conducted to minimize the delivery of
nonpoint source pollutants to streams and other surface waters. Road system planning is an
essential part of this implementation measure. Two basic tenets of road planning are to
minimize the number of road miles constructed and to locate roads so as to minimize the risk of
water quality effects. Those two tenets of road planning are excellent and important guidelines
for forest road network planning. Although the drive to reduce costs is what has led to much
recent research on how road planning can be improved, minimizing costs can also be good for
water quality because the fewer road miles and skid trails that are developed to harvest an area,
the less water quality is likely to be adversely affected.
More than any other aspect of forest harvesting and management, forest roads have been
identified as a major source of sediment delivered to streams and wetlands in forests. Soil
sediment delivered to streams affects public resources such as water quality, aquatic and
wildlife habitat, and riparian resources. Soil sediment causes problems when three
components—source, resource, and delivery—are combined. Roads that are not eroded do not
have the source to cause sediment problems. Roads that are far from streams do not have the
resource to cause sediment problems. Roads that have adequate drainage structures to deliver
the sediment onto stable forest floors do not deliver the sediment to the stream.
Forest roads have an important role in managing forest resources. They need to be constructed
in such a way that forestry workers and machines can gain access to operational sites and carry
out operations safely and efficiently. On the other hand, forest roads are at risk of road surface
erosion and are subject to cut-and-fill slope failures. Therefore, it is important that forest road
design incorporates consideration of cost efficiency and the appropriate management of water
and soil.
Best Management Practices
1. If feasible, consider using a combination of geographic information system (GIS) data,
Light Detection and Ranging (LiDAR) data, and one of the many computer optimization
techniques modified for use in natural resources and forest harvest planning to
determine road layouts, road and skid trail combinations, and landing locations that will
4-12 Chapter 4. Forestry
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
minimize the amount of road construction or skid distance, or both, expose the least
amount of forest soil, and minimize the risk of water quality degradation from harvesting.
GIS data are widely available today for many areas of the country, and where they are not
available, they are easy to collect quickly using a handheld GPS device. LiDAR is a remote
sensing technique that is rapidly being incorporated as a common technique in natural
resources planning. Forest harvest planning, including road network layout and determining a
best combination of roads and skid trails for an area is a field where computer optimization is
being used with increasing success.
Designing a road network and determining an ideal combination of roads and skid trails to
minimize cost and maximize water quality protection is difficult because so many possible
layouts exist. Computer optimization techniques permit forest planners to analyze many more
possibilities than manual techniques and can arrive at an optimum solution using any desired
set of weighed factors.
Discussion
The location and operation of forest machinery, and the design and construction of forest roads
are important issues in forest planning and account for up to 55 percent of production costs
(Epstein et al. 2006). A major challenge of any forestry operation is designing an operation that
minimizes the costs of road construction, installing and operating harvest machinery, and
transporting timber, while at the same time protecting the forest environment. Forest planners
are increasingly using computerized approaches to forest planning to reduce costs, collect the
information necessary to plan a harvest, find road and landing layouts that minimize forest
disturbance, and determine how best to manage existing road networks.
Aruga et al. (2005b) used two computer optimization techniques (the genetic algorithm and
Tabu search) in combination with linear programming and compared the results obtained with
the computer approaches to a manually designed forest road profile. They found that the
profiles designed by computer cost less than the manually designed profile, that using such
optimization techniques found good solutions for road system layout in a reasonable amount of
time, and that more road profile alternatives could be evaluated in less time using computers.
Aruga et al. also looked at the effect of the number of road profile control points (used in the
optimization programming) on construction costs, and their results indicate that increasing the
number of control points reduces the construction costs. That results from the forest road profile
becoming closer to the ground profile—and the earthwork volume then being reduced—as the
number of control points is increased (Aruga et al. 2005b).
LiDAR is a commercially available remote sensing system that is used in natural resources
applications. LiDAR is a laser system that calculates the 3-dimensional (3D) coordinates of
Chapter 4. Forestry 4-13
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
objects from reflections on the earth's surface (Akay et al. 2009). Various forestry activities can
be performed rapidly and efficiently using LiDAR remote sensing technology. From the scans,
various structures of individual trees, including crown width, diameter, volume, and height, can
be estimated. The last scan can provide a very high-quality Digital Elevation Model (DEM) with
approximately 1-meter (m) spatial resolution and about 10 to 20 centimeter (cm) height
accuracy (Akay et al. 2009), which is useful for road and landing layout planning.
Forestry activities can sometimes be done more quickly and less expensively using LiDAR than
using ground-based systems for wide-scale areas. LiDAR is one of the fastest growing
technologies in the natural resources field and it is expected to provide higher resolution and
more accurate data as the technology and GIS technologies advance (Akay et al. 2009). Of
course, the use of technologies such as LiDAR and GIS must be balanced against the current
availability of information about a forest stand, the cost of the technology, and the size of
intended harvest. Small harvest operations, such as those typical of nonindustrial private forest
landowners, might not benefit as much from the use of the technologies as would larger,
corporate forest owners.
Aruga (2005) emphasizes the importance of using DEM and LiDAR data over something such
as computer assisted drawings (CAD), which are widely used to draw road plans, road profiles,
and cross sections, and to calculate earthwork volumes. But when planning a complicated road
system for accessing numerous locations that might not be accessible from existing roads, CAD
is not well suited to finding the best alignment with the lowest total road cost that is made up of
construction, maintenance, user, social, and environmental costs. For such a complicated
calculation, Aruga (2005) recommends using a high-resolution DEM derived from LiDAR data,
which is then used to optimize horizontal and vertical alignments of forest roads. Where primary
and secondary access routes are required, road intersection points are selected manually, from
which the computer program using the DEM and LiDAR data generates alternative horizontal
and vertical road alignments. The DEM generates ground profile and cross sections and
calculates earthwork volumes for curved roadways. It also estimates construction and
maintenance costs. The optimization model used by Aruga (2005) can find the best solution
taking all the factors into account, and it helps forest engineers design a forest road by
evaluating many alternatives (Aruga 2005).
Aruga et al. (2005a) also used a program to optimize forest road alignments but combined it
with a method for predicting surface erosion and sediment delivered to streams, again using a
high-resolution DEM. Because the program generates forest road alignments using a high-
resolution DEM, it can calculate factors required by standard methodology to predict soil
sediment delivered to streams. Aruga et al. (2005a) investigated the effects of road surface
materials, culvert distance to stream, and out-sloped roads on total road costs and soil sediment
delivered to streams. Using the model, Aruga et al. (2005a) found that using lower-quality rock
4-14 Chapter 4. Forestry
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
surfacing on forest roads reduced total costs, but the amount of soil sediment from lower-quality
rock surfacing was 1.5 times more than that on a higher-quality rock surface, and recommend
that lower-quality rock surfacing not be used near streams. They also found that placing near-
stream culverts 15m upstream and using an out-sloped road template significantly reduces total
road cost and soil sediment. Using the model permitted Aruga et al. (2005a) to successfully
optimize forest road alignments, which reduced total road cost and soil sediment.
Other researchers have also been investigating the use of computer programming for forest
planning. Epstein et al. (2006) used a mixed-integer programming system, PLANEX, that
incorporates many parameters like the technical characteristics of machinery operation, road
construction, transport and harvest costs, exit points, and economic variables that restrict the
harvest. GIS was used in the process to provide timber volumes, topographic information, and
information on the existing road network. Forestry companies have applied the technology and
have reported that its advantages include operation designs that use fewer roads, which
translates into lower total costs and the environmental benefits that come from less ground
disturbance (Epstein et al. 2006).
Numerous authors have investigated the use of computer programs to find optimal road layouts
for forest harvesting. Najafi et al. (2008) developed a method to evaluate forest road network
variants using a systematic grid layout. They collected terrain condition and stand data at grid
points using GIS and prepared maps of forest potential for road construction and maps of forest
capacity for harvesting on the basis of the data they collected. A primary objective of the work
was to determine whether the environmental impacts and costs of road network development
could be reduced using GIS technologies. They determined that the method can be used to
evaluate road networks easily, precisely, and in detail, with very little cost incurred to gather the
grid point data (Najafi et al. 2008).
Ghaffarian et al. (2007) used an optimization program to find an optimal layout for a forest
harvested by skidder in northern Iran. The program showed which roads could be eliminated from
the existing forest road network, thus reducing the potential for road failure and sediment runoff
and road maintenance costs, while still permitting efficient forest harvest (Ghaffarian et al. 2007).
Chung et al. (2008) developed a road network optimization model and applied it to a 11,540-acre
(4,760 hectare) forest in the upper part of the Mica Creek watershed in Idaho, an area owned by
Potlatch Forest Holdings. The model is used to identify cost-efficient road networks for timber
harvesting given cost constraints and with options for on-road transportation of logged timber on
new roads and off-road timber transportation using skidders, taking into consideration terrain
conditions and stream locations. Costs that are input to the model and that partially determine the
outcome include timber volume, road construction cost, skidding cost, and stream crossing cost
(Chung et al. 2008). The latter purposefully tends to favor fewer or simpler stream crossings.
Chapter 4. Forestry 4-15
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
The model selects the least-cost activity using costs of skidding versus road construction and
timber volume. For example, if enough timber volume is in an area or road construction cost is
low compared with skidding cost, the road building option is selected so as to decrease the
average skidding distance. On the contrary, if timber volume is not large enough or road cost is
high, the skidding option is selected because building a new road would not be economically
feasible even though the average skidding distance increases. Such a process eventually
generates a road network that most cost-efficiently serves the entire area of interest for the
purpose of timber harvesting (Chung et al. 2008).
Rackley and Chung (2008) used NETWORK2000, a forest transportation planning model, to
produce alternative road system layouts that simultaneously minimize transportation costs and
overall sediment delivery using inputs of estimated sediment delivery. They applied the
methodology to the Mica Creek watershed in northern Idaho, where 11 alternative road
networks were developed. The results of the modeling effort indicates that incorporating
environmental effects into transportation planning can generate alternative road networks that
reduce a large amount of estimated sediment delivery at the expense of a relatively small
increase in transportation costs (Rackley and Chung 2008).
It is important to be able to include all relevant factors in any computerized system for optimizing
forestry operations, because while many methods of finding optimal landing locations and
determining the best skidding distance have been developed, they simplify harvest units and do
not consider many factors that influence landing, skid trail, and road location (Contreras and
Chung 2007). Contreras and Chung (2007) used a computerized model to determine the
optimal landing location for harvesting using raster-based GIS data. The model found skid trails
from stump to candidate landing locations and selected the best location on the basis of
minimizing total skidding distance and spur road costs. The model included harvest unit
boundary shapes, volume distribution, obstacles, terrain conditions, and spur road construction
as factors taken into account in the optimization task. Using the model, Contreras and Chung
(2007) found a range of cost savings associated with the various factors to be from $0 to
$9,443, with an average savings per factor considered of $1,788. Data needed for the model
are easy to obtain because LiDAR and GIS can provide most of it (Contreras and Chung 2007).
LiDAR can also be used to obtain detailed information on a forest harvest area (Akay et al.
2009). A LiDAR data set for forested areas is generated by light pulses reflected from different
levels of vegetation canopy, including the top of the vegetation surface (first return),
intermediate surfaces (second and following returns), and the ground surface (last return). From
the first and second returns, various structures of individual trees (crown width, diameter,
volume, and height) can be estimated. Using the last return, LiDAR can provide a very high-
quality DEM. LiDAR is one of the fastest growing technologies in the natural resources field, and
4-16 Chapter 4. Forestry
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
it is expected to provide higher resolution and more accurate data as the technology and GIS
technologies advance (Akay et al. 2009).
1b. Where the use of LiDAR and DEM are not feasible (for instance, because data are
lacking or because their use is too costly), consider integrating the use of digital
topographic maps and aerial photography with data collected using a handheld GPS unit
for forestry planning.
A handheld GPS unit combined with freely available or low-cost digital topographic maps and
aerial images is a method ideally suited to forest planning uses for small properties to determine
harvest unit boundaries, road layouts, road and skid trail combinations, and landing locations.
LiDAR and DEM are expensive, technology-intensive tools for forestry operations that are
suitable for use by large-scale forestry operations and government agencies, but they are
beyond the reach of smaller forest owners. A handheld GPS receiver used in combination with
digital topographic maps and a computer mapping program is technology that is within the reach
of and suitable for small forestry operations, such as those typical of nonindustrial private
landowners. A variety of functions related to forestry—including collecting and storing specific
GPS points, paths, and routes, and transferring the stored information between the GPS unit
and a computer—can be performed with a handheld GPS receiver. Distances and areas can be
calculated in the field or afterward on a computer using a mapping program, and adjustments to
boundaries and paths can be made in the computer and then transferred back to the GPS unit
for later use in the field, if necessary. Using a simple GPS receiver, a landowner or forester
could gather complete location information on a forest unit to be harvested, walk candidate
access road and skid trail routes while collecting GPS locations, and then conduct final harvest
planning in more detail on a computer using a free or commercially available computer digital
mapping software package. Free software packages include USAPhotoMaps, Google Earth,
EasyGPS, and GPS Utility, while commercial software is available for purchase if required to
provide greater accuracy and up-to-date maps.
2.3 Streamside Management Areas (SMAs)
Implementation Measure F-2:
Establish and maintain an SMA along all (perennial and ephemeral) waterbodies.
Avoid all activity inside SMAs along all waterbodies. SMAs should be wide enough
to provide a preharvest level of shade to surface waters, detain and capture water
and sediment runoff from the harvest site and roads, and a sustainable source of
large woody debris for in-stream channel structure and aquatic habitat.
Chapter 4. Forestry 4-17
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
Section 3B of EPA's guidance, National Management Measures to Control Nonpoint Source
Pollution from Forestry (USEPA 2005) presents EPA's recommendation for SMAs in areas
affected by forestry activities such as harvesting and post-harvest site preparation. The 2005
guidance describes the implementation measure, discusses the benefits of SMAs, and presents
BMPs that can be used to meet the intent of the implementation measure.
The recommendations of the 2005 guidance with respect to SMAs still hold. Forested areas
along streams and rivers are considered vital for providing habitat, food, and shelter for wildlife
and protecting water quality by reducing nutrient and sediment input from upland areas. The
Chesapeake Bay Program Forestry Workgroup emphasized the importance of streamside areas
when it developed the 2003 Directive for Expanded Riparian Forest Buffer Goals (CBP 2003).
The directive recommends that forest buffers exist on at least 70 percent of all shorelines and
streambanks in the Chesapeake Bay watershed. An estimated 60 percent of the shorelines in
the watershed are now forested. Protecting the forests along streams in areas harvested for
wood products is one of the key components to achieving the goal of the 2003 directive.
Most states incorporate SMAs as a major component of their forestry practice guidelines, and
the recommendations of the states for establishing and protecting SMAs in harvest areas to
protect water quality have not changed since publication of the 2005 EPA guidance. A general
rule for the width of an SMA is a minimum of 25 to 50 feet, with 5 feet of additional width added
for each 1 percent of slope of the contributing land (Klapproth and Johnson 2000). Of course,
state, federal, or other applicable guidelines or rules for SMAs must be followed where they are
applicable. For instance, many states (e.g., Virginia, Kentucky, Georgia, North Carolina, and
South Carolina) prescribe wider SMAs along waters that protect cold water fisheries (Hodges
and Visser 2004).
The importance of SMAs for water quality protection is well-established. Over the past 5 to
7 years, researchers have been investigating the use of technology for improving the accuracy
and ease with which variable-width SMAs can be established. Technology has also been
applied to preventing concentrated runoff flows from entering and passing through SMAs to
reach streams. Also, in response to landowner concerns over lost revenue by not harvesting
in SMAs, researchers have investigated the extent to which thinning in SMAs might be
permitted while still retaining the nutrient- and sediment-trapping capabilities of the SMA.
Recommendations to augment the information on SMAs in the 2005 EPA guidance are provided
below, and the findings of the recent research are summarized. For more information on SMAs,
see the Riparian Section.
4-18 Chapter 4. Forestry
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
Best Management Practices
1. Use GIS data or digital topographic maps and a GPS unit to determine SMA
boundaries.
Field-based determination of variable-width SMA boundaries is a time-consuming process that
can sometimes be accomplished in less time using GIS data or digital topographic maps. The
width of SMAs is measured horizontally from the streambank, and the slope of land often varies
along a stream course, which requires an SMA with a width that varies with the slope. Using
GIS data or digital topographic maps, slope, and distance to stream, boundary points for an
SMA can be determined quickly and accurately. Those points can then be loaded onto a
handheld GPS unit and taken into the field for marking before harvest.
2. Use high-resolution stream maps when planning SMAs to ensure that all streams are
protected.
When planning for stream protection, it is important to use the highest resolution stream map
available. Lower resolution maps might not indicate the location of lower-order and ephemeral
streams. When SMAs are planned, if these streams are left unprotected, water quality could be
seriously compromised during and after a harvest.
Discussion
SMAs are delineated along streams in forested areas before harvesting. Generally, the width of
an SMA varies by the slope of the terrain perpendicular to a stream, with the width increasing as
the adjacent slope increases. That is because additional distance is necessary to prevent more
rapidly moving runoff from reaching a stream channel. The process of establishing a variable-
width SMA involves extensive field mapping, which requires traversing streams, measuring side
slopes, determining where the limits of the SMA should be, marking the boundaries for easy
identification during the harvest, and transferring the boundaries to aerial photos and
retransferring them to the forest planning map. Although a variable-width SMA is advantageous
for water quality protection, such an involved process of establishing them complicates forest
operation planning (Williams et al. 2003). Williams et al. (2003) discuss how managers can use
GIS as an aid to forestry management planning by accurately mapping SMAs without the need
for on-the-ground field determinations. Basically, the process involves using maps of stream-
bottom position and the topographic information in a GIS database to accurately and quickly
determine the boundary location of variable-width SMAs. Details of the GIS software approach
to delineating and mapping variable-width SMAs are provided by Williams et al. (2003).
Baker et al. (2007) evaluated the influence of stream map resolution on measures of the stream
network and explored how predictions of nutrient retention potential might be affected by the
resolution of a stream map. They noted that stream network maps from a broad range of map
Chapter 4. Forestry 4-19
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
resolutions have been employed in watershed studies of riparian areas and were concerned
that map resolution could affect important attributes of riparian buffers determined from the
maps—for instance, the connectivity between source lands and small stream channels could be
missing on coarse-resolution maps. They found that using fine-resolution stream maps
significantly increased estimates of stream order, drainage density, and the proportion of
watershed area near a stream (Baker et al. 2007).
When Baker et al. (2007) used stream maps of decreasing resolution for the same area,
estimates of the mean distance from streams to source areas and mean buffer width were
reduced, and the areas found to be unprotected by streamside buffers increased. Increasing the
stream map resolution revealed portions of river networks reaching out farther into landscapes
and closer to watershed divides, dissecting the landscape more finely while simultaneously
decreasing the average proximity of the stream channels throughout watersheds (Baker et al.
2007).
Measures of percent land cover within 100 m of streams were found to be less sensitive to
stream map resolution, and overall, increasing stream map resolution led to reduced estimates
of nutrient retention potential in riparian buffers (Baker et al. 2007). That study also
demonstrated that stream map resolution can also affect a user's ability to determine whether
sediment retention occurs in riparian zones. In some watersheds, switching from a
coarse-resolution to a fine-resolution stream map completely changed the perceptions of the
authors of a stream network from one that was well-buffered to one that was largely unbuffered.
Best Management Practice
1. Establish wider-than-recommended SMAs where an SMA of recommended width will
not sufficiently protect water quality.
The width of SMAs is generally prescribed by state or local ordinance, but under some
circumstances, it can be too narrow to adequately protect water quality. For instance, the litter
layer in an SMA is critical to stopping sediment- and nutrient-laden runoff from reaching
streams. If the litter layer is disturbed or lacking, an SMA might have to be wider than
recommended to adequately stop runoff.
Similarly, sediment and nutrients can be trapped as runoff infiltrates into the soil. But if the soil in
an SMA has poor infiltration, runoff that does reach the SMA is more likely to reach surface
waters. Extending the width of an SMA where soils have poor infiltration provides extra distance
between the sediment and nutrient source to surface waters within which runoff can be slowed
and stopped to prevent water quality degradation.
4-20 Chapter 4. Forestry
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
Discussion
White et al. (2007), working in the Piedmont region of Georgia, noted that a large portion of
sediment is removed in the first 2 m of forested filter strips whether they are disturbed or not. In
their study, only 2-3 percent of the total sediment was removed in each meter beyond the first
2 m. Significant reductions also occur in finer, silt-sized sediment in undisturbed filter strips, and
"it appears that it is within this size fraction that increased filter strip width is the most important."
If fine sediment is a concern, according to White et al. (2007), a 16-m filter strip should be
sufficient to reduce the 2- to 20- micrometer (urn) particle concentrations in runoff to near zero.
Filter strips will have little effect on surface flow sediment concentrations, however, where
delivered sediment is colloidal size. That points again to the importance of considering soil
characteristics when determining the appropriate SMA width for water quality protection.
White et al. (2007) also recommend that forested filter strip width be based on soil infiltration
characteristics. They also note a trend toward increased sediment retention with increased
depth of the litter layer, so it is probable that using harvesting equipment in an SMA would affect
the litter layer and reduce sediment retention. In areas where coarse sediment is of concern,
narrow filter strips should provide sufficient opportunity for settling and should be effective even
if relatively little runoff infiltrates the soil. They report that narrow filter strips can remove coarse-
textured sediment (> 20 urn in diameter) and that filter strips 16-m wide should remove most
2- to 20-um sediment from runoff water (White et al. 2007).
The study highlights the potential limitation of using only slope as a tool for prescribing SMA
width during harvesting for nutrient control. There is a disconnect between guidelines for slope
as a modifying factor for buffer width establishment and slope as a causal factor affecting
riparian zone nutrient concentrations. Stand characteristics, particularly the presence of N-fixing
species in riparian areas, can also be an important factor influencing soil N concentrations.
Vegetation in the SMA and soil properties are important factors to consider when determining
the width of an SMA for water quality protection purposes.
Best Management Practice
1. Follow p re harvest plan when harvesting in SMAs where upland, soil, and vegetative or
litter layer characteristics are such that sediment and nutrients would likely be
intercepted before reaching streams in a thinned SMA.
Where water quality would not be compromised and site characteristics are such that runoff
from harvest sites would be stopped adequately before reaching streams, thinning harvests
could be permitted in SMAs. Where permitted, harvesting in SMAs should always be done using
techniques that minimally disturb the litter layer or compact soils. Additionally, managers must
consider factors other than water quality protection when determining whether to permit thinning
in SMAs. For instance, adequate shade should be provided post-harvest to regulate stream
Chapter 4. Forestry 4-21
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
temperature in streams home to temperature-sensitive fish species, such as trout. Also, an
adequate number of trees to supply woody debris to the stream must be retained to ensure the
ecological health of stream biota.
Discussion
Lauren et al. (2007) investigated the possibility that SMA thinning could accommodate both the
landowner's desire to maximize timber revenue and the need to protect water quality. While it is
established that uncut buffer zones between clear cuttings reduce export of nutrients, they also
reduce harvested stock and harvest revenue, a common and justified concern of landowners.
Thinning in buffer zones could increase the volume and revenue of a harvest, but the effect of
thinning on nutrient export is not well known. Lauren et al. (2007) compared N export in a 90-m,
unthinned buffer zone to that in a 10-m, thinned buffer zone and found that the N export
decreased by 53.4 kilograms (kg) in the 90-m, unthinned buffer zone but by only 4.3 kg in the
10-m, thinned buffer zone. Interestingly, however, was their conclusion that a prescribed target
for water quality protection (e.g., reduce N export from a watershed by 25 kg in 5 years) can be
achieved with several management options, or by combining different management schemes.
For example, a buffer zone around a stream could be divided into subzones, such as an area in
which clearcutting is permitted with restricted site preparation, another zone in which thinning is
permitted without the need for site preparation, and a third, completely unmanaged zone.
Rivenbark and Jackson (2004) also noted the possibility that SMAs consisting of subzones could
be used to meet water quality goals. If the relative strengths of the types of zones for nutrient and
sediment reduction are known for an area, for a given water quality protection goal, a mixture of
zones in which different harvesting activities are permitted and required could be recommended
depending on individual landowner needs and site characteristics (Lauren et al. 2007).
2.4 Forest Road Construction/Reconstruction and Forest
Road Management
Implementation Measures:
F-3. Guard against the production of sediment when installing stream crossings.
Maintain permanent stream crossings and associated fills and approaches to
reduce the likelihood (a) that stream overflow will divert onto roads and
(b) that fill erosion will occur if the drainage structures become obstructed.
F-4. Protect surface waters from slash and debris material from roadway clearing.
F-5. Expedite the revegetation of disturbed soils on unstable cuts and fills. Use
temporary structures such as straw bales, silt fences, mulching, or other
appropriate practices until an area is adequately stabilized.
4-22 Chapter 4. Forestry
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
F-6. Conduct maintenance practices, when conditions warrant, including
cleaning and replacing deteriorated structures and erosion controls, grading
or seeding road surfaces, and, in extreme cases, slope stabilization or
removing road fills where necessary to maintain structural integrity.
F-7. Evaluate the future need for a road and close roads (including temporary
spur roads and seasonal roads) that will not be needed. Road closure should
include stabilizing closed roads and drainage channels against failure
during storms, ensuring that runoff from a closed road will be directed away
from the roadway, removing drainage crossings and culverts if there is a
reasonable risk of plugging, and removing all temporary stream crossings.
EPA's 2005 forestry guidance emphasizes the importance of good road planning for preventing
sediment delivery to streams in the Road Construction/Reconstruction and the Road
Management implementation measures. Road construction remains one of the largest potential
sources of forestry activity-produced sediment, and providing road and drainage crossing
structures that minimize the potential for sediment delivery to surface waters from roads,
landings, and skid trails is still an essential task for long-term water quality protection from forest
roads.
Road planning and construction can be even more effective today by using advances made in
computerized techniques to find the best layouts for roads that can reduce both costs and the
potential for road runoff to reach streams.
Forest roads also need to be maintained to correct breakdowns in road drainage structures that
can lead to sediment runoff and inputs to streams. When properly planned and constructed,
forest road drainage prevents or minimizes the connection between road runoff and the stream
network. When roads are left unmaintained, road drainage paths can lead to the stream
network. Road drainage hydrologically connected to the stream network is a direct path for
sediment input. Additionally, managers should analyze forest roads that are no longer needed,
and determine whether returning them to vegetative cover would reduce the risk of sediment
runoff.
Best Management Practices
1. Provide extra road drains, especially near streams and stream crossings, to minimize
the creation of concentrated runoff flows
In addition to protecting the litter layer and extending SMAs in areas with poor soil infiltration, it
is important to ensure that roads and skid trails near drainages and streams are kept
Chapter 4. Forestry 4-23
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
hydrologically disconnected from the drainage network. Such a practice means that road
segments near streams and stream crossings could need extra drainage structures installed
and runoff directed away from streams to minimize the chance of sediment-laden runoff
reaching a stream.
Discussion
Preventing concentrated runoff flow from reaching SMAs—or stopping concentrated flows within
an SMA if they do reach it—is important to protecting water quality. Rivenbark and Jackson
(2004) surveyed SMAs in the Georgia piedmont to determine the efficacy of BMPs in preventing
concentrated overland flow. Recording where flow broke through SMAs and where it did not
break through to streams, they found that 50 percent of breakthroughs were at areas of
convergence (swales) and gullies, and 25 percent were concentrated runoff from roads or skid
trails. They determined that breakthroughs tend to occur in areas with a large contributing area,
little litter cover, and steep slopes. They recorded some breakthroughs that traveled 100 feet
before being filtered. More than half of breakthroughs traveled 50 feet before reaching stream
channels and 14 percent traveled more than 100 feet before reaching streams, though 75
percent of breakthroughs were stopped within the first 20 feet of an SMA. Runoff travel distance
before dispersal was not really related to slope, and breakthrough frequency did not differ
between sites that were prepared post-harvest and sites that were clearcut and not prepared
(Rivenbark and Jackson 2004).
Rivenbark and Jackson (2004) noted the importance of protecting the litter layer in an SMA to
prevent concentrated flow from reaching the stream channel. In looking at concentrated flow,
White et al. (2007) recorded significant formation of concentrated flow after runoff had traveled 6
m through forested filter strips. According to their study, removing the litter layer can have a
major effect on overland flow travel time, especially on steeper slopes. On terrain of the same
slope but with a disturbed and undisturbed litter layer, runoff from the terrain with the disturbed
litter layer traveled 40 seconds per meter faster on 15-17 percent slopes and 12 seconds per
meter faster on 5-7 percent slopes (White et al. 2007).
The effectiveness of SMAs in protecting water quality, therefore, could be improved by
protecting the litter layer, dispersing road runoff better, introducing hydraulic resistance to likely
flow paths, and widening SMA at key locations (Rivenbark and Jackson 2004). Additionally, the
width of SMAs could be varied on the basis of physical features of the site. For instance, SMAs
could be extended in sensitive areas, their width could be based on the potential hydrologic load
of upland areas rather than being a set width, they could be wider where the contributing area is
large and slopes are steeper, and a sub-SMA—a width beyond the primary SMA—could be
established where clearcutting is allowed but ground cover is not disturbed and burning and
herbicide use is prohibited. It could also be beneficial to stack logging slash along SMA
boundaries to intercept and slow concentrated flows (Rivenbark and Jackson 2004).
4-24 Chapter 4. Forestry
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
2. Analyze the connectivity of a road network to streams (using computerized models
and risk analysis, if feasible) to determine where the risk of sediment runoff to streams is
greatest and where roads maintenance efforts should be concentrated, or road sections
should be removed or modified.
Within a forest road network, a small portion of the road surface generally contributes
disproportionately to water quality deterioration. Finding out which road segments are
responsible for water quality deterioration can best be accomplished with computerized
techniques that can analyze a variety of information about individual road segments to
determine those where maintenance or decommissioning will have the greatest effect.
Discussion
The computer programming methods mentioned above are best used to plan a forest road
network before one has been constructed to minimize costs and environmental damage.
Computerized techniques for managing existing forest road networks, including road
maintenance for water quality protection and road decommissioning, are also being developed.
Because runoff and sediment delivery is the dominant process by which water resources are
affected by forestry activities, the concept of a forest road system's hydrological connectivity to
a stream network has been the focus of much recent research. By managing runoff delivery
pathways and the resultant pattern of hydrological connectivity of the road system to the stream
network, the potential adverse effects of forest harvesting on in-stream water quality can be
limited (Croke and Hairsine 2006).
Computer programming methods are not necessarily needed to analyze small forest road
networks where main access roads lead off of public roads and feeder roads are either limited in
number or lacking. Under such circumstances, field monitoring of road conditions performed at
regularly scheduled intervals or after storms to check for signs of erosion and road failure
should be sufficient to determine where road maintenance or road decommissioning is
necessary to minimize water quality impacts.
The various links between site runoff, transport, and movement through an extensive forest
system into the river system at a site can be difficult to quantify accurately partly because it is
difficult to accurately measure the amount of sediment and attached nutrients delivered to,
stored and remobilized within, and eventually transported from a river system (Croke and
Hairsine 2006). A combined approach of reducing the source strength and enabling the delivery
path to trap mobilized sediment, thereby reducing connectivity, is a sound approach to
managing the sediment delivery problem.
Three types of runoff delivery pathways from forest roads exist: stream crossings, gullied
pathways, and diffuse pathways (Takken et al. 2008). Sediment delivery to streams depends on
Chapter 4. Forestry 4-25
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
source strength and the characteristics of the delivery path. Importantly, the degree of
connectivity of a road to surface waters depends on catchment characteristics such as
topography, road placement, drain spacing, and road and drainage density (Takken et al. 2008).
Takken et al. (2008) evaluated the risk of road-derived runoff delivery. They created risk
assessment maps using road-stream hydrological connectivity to highlight hot spots and to
evaluate procedures for road rehabilitation. Examining the relatively steep Albert River
catchment in Australia, they found that diffuse overland flow could be minimized with additional
road drains, particularly by adding more stream crossings per kilometer (km) of road where
drainage area is large and roads are lower on the hillslope. Road segments that are highly
connected to the stream network, however, were found to require the relocation of the road to
manage sediment delivery to streams (Takken et al. 2008).
Croke et al. (2005) demonstrated that a strong association exists between runoff pathway and
drain type. They found that most (90 percent) of gullied pathways were at culvert pipes that
drain cut-and-fill roads, whereas miter drains and push outs were predominantly associated with
dispersive pathways. They studied main access roads, feeder access roads, and minor access
roads. Initial sediment concentrations at road outlets ranged from 2 grams per liter (g/L) to
15 g/L and were highest from well-used main access roads compared with less-frequently used
feeder access and dump access roads. Road usage alone explained 95 percent of the variation
in sediment concentrations in runoff from the road surfaces studied. Most (more than
50 percent) sediment in runoff from the road outlets was silt- and clay-sized material, but
sediment concentrations in runoff plumes from main access roads had about 3.5 times higher
concentrations of < 63-um material than those from feeder access roads (Croke et al. 2005).
Croke et al. (2005) concluded that the potential effect of road-related sediment on in-stream
water quality can best be assessed in terms of the nature and connectivity of the delivery
pathway. Forest roads have a delivery pattern largely determined by runoff source strength and
connectivity. Connectivity is the arrangement and location of drainage structures such as
culverts and miter drains with respect to the natural drainage system in the catchment (Croke et
al. 2005).
Examining the hydrological connectivity of a forest road network and stream system can help
determine where best to focus efforts to reduce sediment and nutrient inputs to surface waters.
Fu et al. (2007) developed and applied a road erosion and sediment transport model. In the
areas in southeastern of Australia that they studied, approximately 21 kilotons (kt) and 35 kt of
sediment were produced annually from road erosion. They found that less than 10 percent of
the sediment produced was delivered to streams, and about half of the delivered sediment was
derived from only 4 percent of the total road network (Fu et al. 2007).
4-26 Chapter 4. Forestry
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
Allison et al. (2004) conducted research to demonstrate that decision analysis can be used to
organize the complex nature of forest road decisions using road deactivation as an example
decision. Road segments that are candidates for deactivation were ranked using factors of
interest, which in the case of this study was to reduce the susceptibility of roads to landslides
and debris flows. The rankings distinguish between road sections that offer high expected
benefit from those that offer moderate to low expected benefit. Allison et al. (2004) applied the
analysis to an area with steep terrain, but it could be applied to any terrain type and with various
factors of interest. They found in their case that 17 of 171, 100-m road segments accounted for
18 percent of the cumulative cost of deactivation, but 98 percent of the cumulative expected net
benefits from road deactivation. The results point out that some road segments have a higher
benefit-cost ratio than others and that most of the total potential restoration benefit (reduced
sediment delivery to streams, maintenance cost, and such) can be obtained from a small
proportion of the total road network and potential cost (Allison et al. 2004).
Road decommissioning is expensive, and Eastaugh et al. (2007) assessed the outcomes of
different forest road decommissioning options to determine whether costs and environmental
impacts could be lowered. They present a method of quantifying the degree to which a road is
hydrologically connected to a stream network and the likely effects of different configurations of
road construction on water quality. Their method permits the quantification of road/stream
connectivity without the need for extensive parameterization, which reduces both the time and
cost of implementing the method. They noted that several models exist for predicting road-
derived sediment production and delivery, but those models suffer from the practical
disadvantage of being highly parameterized, requiring a large number of input data that are
often difficult to obtain or accurately estimate. In contrast, the method used by Eastaugh et al.
(2007) uses a high-resolution DEM based on 1-m spaced LiDAR measurements to represent
catchment topography. The road morphology data necessary for the evaluation was collected
during an intensive field survey using a GPS receiver to record the location of road edges,
culvert locations, and drain outlets from the road surface (Eastaugh et al. 2007).
Eastaugh et al. (2007) applied the model to an actual road decommissioning and replacement
project in southeast Australia. For the application, road areas and drainage outlets were
surveyed in the field and flow paths to streams were derived from a 1-meter resolution LiDAR-
based DEM. The results of the application demonstrated that the road decommissioning project
examined would have been unlikely to reduce runoff to the stream network and that the overall
effect of the decommissioning would likely have been a net reduction in stream water quality
from increased sedimentation (Eastaugh et al. 2007).
Chapter 4. Forestry 4-27
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
Best Management Practices
1. Avoid having traffic on forest roads when road water content is high.
Truck traffic on forest roads when the water content of the road is high leads to deformation of
the road surface, which redirects runoff and reduces the effectiveness of drainage structures.
2. Use aggregate on forest roads near stream crossings.
Sediment runoff from roads surfaced with an aggregate chosen to withstand the intended traffic
load can be much less than from unprotected roads or roads with an aggregate of insufficient
quality to handle the traffic load. It is especially important to protect and maintain roads near
streams and stream crossings.
Discussion
Suspended sediment makes up 96 percent of the total sediment load from runoff, and a
practical option to limiting it in runoff is to reduce the generation rate by surfacing roads
adequately with aggregate and maintaining road drainage so it functions as intended (Sheridan
etal.2006).
Sheridan et al. (2006) investigated the effect of truck traffic intensity on runoff water quality from
unsealed, gravel-surfaced forest roads. In their studies, traffic explained 36 percent of the
variation in erodibility, pointing to the importance of adequately surfacing and maintaining forest
roads. Under wet-road conditions, it is common for the cross-sectional profile of a road to
become deformed by longitudinal rutting caused by traffic. That compromises lateral road
drainage and concentrates flows along the road surface, bypassing drainage structures and
leading to rilling of the road surface and high sediment generation rates (Sheridan et al. 2006).
The results of Sheridan et al. (2006) indicate that surfacing a road adequately and maintaining it
in good condition can reduce sediment production.
Roadside ditches and other drainage features often produce finer sediment than natural
conditions, and roads with only marginal-quality aggregate containing low-durability fine
particles can produce 4 to 17 times more sediment than those with good-quality aggregate
(Witmer et al. 2009). Witmer et al. (2009) recommend that because of limited budgets and the
need for cost-effective water quality protection, a priority listing of unpaved road-stream
crossings is needed before restoration and sedimentation reduction strategies can be
implemented.
Witmer et al. (2009) addressed the problem of determining where to focus road rehabilitation
efforts by developing a sedimentation risk index (SRI) for unpaved road/stream crossings to
help managers determine which road-stream crossings should receive priority for restoration
4-28 Chapter 4. Forestry
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
and sedimentation reduction. The SRI created by Witmer et al. uses 12 metrics to weigh factors
involving soil erodibility, road sedimentation abatement features, and steam morphology
alteration to arrive at a final index score for each stream crossing. All types of stream
crossings—round culvert, box culvert, and bridge—can be included, and they found no
significant difference in SRI scores among crossing structure type, indicating that one type is not
necessarily better when it comes to less sediment production than others. Limited budgets
make prioritizing unpaved road crossings a key means for efficient sedimentation abatement,
and the SRI or a similar rating scheme can be used to make water quality protection more
effective (Witmer et al. 2009).
2.5 Timber Harvesting
Implementation Measures:
F-8. Install landing drainage structures to avoid sedimentation to the extent
practicable. Disperse landing drainage over stable side slopes. Protect
landing surfaces used during wet periods. Locate landings outside SMAs.
F-9. Conduct harvest and construct landings away from steep slopes to reduce
the likelihood of slope failures.
F-10. Protect stream channels and significant ephemeral drainages from logging
debris and slash material.
The goal of the Timber Harvesting implementation measure in the 2005 guidance is to minimize
the likelihood of water quality effects resulting from timber harvesting. Precautions taken during
preharvest planning to minimize road and skid trail miles, and follow the contour of the land to
the extent feasible, are important aspects of protecting the forest floor from disturbance. Using
equipment well suited to the topography and forest type to limit erosion and sedimentation
during harvesting operations is also important.
When conducting a harvest, it is important to pay attention to the potential for soil disturbance
from the operation. Doing so can result in improved water quality protection. Disturbances to
forested watersheds can have severe adverse effects on soil and soil nutrients. Road
construction and skidding associated with forest harvesting can cause serious soil disturbance
that can increase suspended sediment in streams. It is vitally important that the forest floor be
protected from disturbance to the maximum extent feasible during all aspects of harvesting.
Chapter 4. Forestry 4-29
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
Best Management Practice
1. When constructing roads, landings, and skid trails, and during harvesting, use
methods that maximize protection of the forest floor to the extent feasible.
Most sediment and nutrient runoff from forest harvest sites originates in areas where the forest
floor has been disturbed and the soil has been exposed, disturbed, or compacted. Protecting
the litter layer and soils of the forest floor where it is possible (that is, where it need not be
disturbed for road construction or skidding) is vital to ensuring the protection of water quality.
Although roads and skid trails are generally maintained or protected after a harvest to limit
sediment runoff, disturbed areas beyond these can go unnoticed and not receive the
rehabilitation that roads and skid trails do to prevent sediment runoff. Unintentionally disturbed
areas also are not usually provided with runoff control features, so any runoff originating from
them could drain unchecked to streams and rivers.
Discussion
Protecting the forest floor outside the SMA is important to protecting the water quality of
forested streams. Surface erosion generally does not occur in an undisturbed forest because of
the infiltration capacity of the litter layer and forest soils (Hotta et al. 2007). Following this logic,
in an unharvested forest where the source area of suspended sediment is limited to the stream,
suspended sediment transport should correspond well with water discharge. Certain forest
practices, such as constructing forest roads and skid trails and serious soil surface disturbances
such as those caused by skidder activity and plowing, are known to increase suspended
sediment yields.
Most studies have investigated the effects of the practices associated with harvesting rather
than the harvesting itself. Hotta et al. (2007) investigated whether harvesting would increase
suspended sediment yields if harvesters took appropriate measures to prevent surface
disturbance, including using skyline logging treatments and piling branches and leaves at
selected locations in the watershed. They performed the study in an experimental watershed in
a steep-sloped forest near Tokyo, Japan. Hotta et al. (2007) measured suspended sediment
yield from areas harvested using such methods and found that annual suspended sediment
yields did not increase despite post-harvest increases in annual water yields. They found that
after harvesting.Jhere were no increases in suspended sediment yields concurrent with heavy
rainfall events, when most suspended sediment was normally transported in the watershed.
They concluded that post-harvest increases in suspended sediment yields can be controlled by
using careful harvesting techniques (Hotta et al. 2007).
4-30 Chapter 4. Forestry
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
2.6 Site Preparation
Implementation Measure F-11:
Protect surface waters during site preparation by
1. Selecting a method of site preparation and regeneration that is suitable for the
site conditions.
2. Conducting mechanical tree planting, ground-disturbing site preparation
activities, and bedding on the contour of sloping terrain and outside SMAs
and ephemeral drainages.
3. Protecting surface waters from logging debris and slash material, including
locating windrows far enough from drainages and SMAs to limit the entry of
material into surface waters during high-runoff conditions.
4. Suspending operations during wet periods if equipment begins to cause
excessive soil disturbance that will increase erosion. Conduct bedding
operations in high-water-table areas during dry periods of the year.
The Site Preparation and Forest Regeneration implementation measure in the 2005 guidance
discusses how important it is to revegetate harvested areas to minimize erosion and runoff from
disturbed soils that could degrade water quality. Vegetative cover on disturbed soils reduces
erosion and slows runoff, and roots stabilize soils. Minimizing disturbance to the forest floor litter
layer during all phases of forestry activities—from road construction to site preparation
operations—minimizes soil compaction and detachment, which helps maintain infiltration and
slow runoff. Such factors, in turn, reduce erosion and sedimentation after site preparation is
complete.
Where soil and the litter layer have been disturbed, and in instances where it would not prevent
the regrowth of planted trees or natural regeneration, protecting the soil by applying wood chips
or slash could be a viable method to both protect the soil and prevent the loss of N from the soil
to surface waters.
Best Management Practice
1. Apply wood chips or slash to disturbed areas after a harvest to reduce nutrient runoff.
N as nitrate is commonly leached from a forest after clearcut harvesting because the N cycle is
disrupted when vegetation that would normally use the N is removed. The amount of nitrate that
is made available for leaching depends on the amount of vegetation removed (generally,
selective cutting or diameter-limit harvesting do not result in nitrate leaching), vegetative
characteristics of the forest, and the time elapsed since the harvest. Nitrate leaching generally
Chapter 4. Forestry 4-31
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
decreases as vegetation regrows on the clearcut site. Applying wood chips derived from logging
slash can significantly reduce nitrate leaching after a harvest during the time when vegetation is
re-establishing itself. The wood chips are thought to immobilize much of the nitrate in the forest
floor.
Discussion
N as nitrate is a pollutant that can be released after forest harvest, especially after clearcutting.
Soil temperature can also be increased, which can increase microbial activity, organic matter
decomposition, and inorganic N production. Homyak et al. (2008) tested whether applying wood
chips derived from logging slash after harvesting would immobilize nitrate and thus reduce its
flux to streams. They applied wood chips to the soil surface in a stand of northern hardwoods
that was patch clearcut in the Catskill Mountains, New York, and found that between 19 and 38
kg of nitrate per hectare were immobilized in the first year after harvesting, depending on the
quantity of wood chips applied, which contributed to water quality protection. They suggest that
additional research on wood chip application as a new BMP after harvesting is warranted,
particularly in regions that receive elevated levels of atmospheric N deposition (Homyak et al.
2008).
Immobilizing nitrate in the forest floor by either leaving some logging slash on the ground or by
adding woody material after logging might be a feasible way to reduce nitrate flux to streams
and limit water quality impacts. Other studies in Japan, the Mediterranean, New Hampshire, and
the Appalachian Mountains have shown similar results (Homyak et al. 2008).
2.7 Fire Management
Implementation Measures:
F-12. Prescribed and wildland fire should not cause excessive erosion or
sedimentation because of the combined effect of partial or full removal of
canopy and removal of ground fuels and the litter layer, to the extent
practicable.
F-13. All bladed firelines, for prescribed fire and wildfire, should be stabilized
with water bars or other appropriate techniques if needed to control
excessive sedimentation or erosion of the fireline.
F-14. Consider the potential nonpoint source pollution consequences on
watercourses of wildfire suppression and rehabilitation activities, while
recognizing the safety and operational priorities of fighting wildfires.
4-32 Chapter 4. Forestry
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
The Fire Management implementation measure in the 2005 forestry guidance emphasizes the
importance of using prescribed fire in a way that does not remove the litter layer so that erosion
is not a problem after a fire. Recent research examines the mechanism by which fire can protect
a forest from erosion or expose it to erosion and emphasizes the importance of fire
management to protect a forest from post-fire erosion.
Best Management Practice
1. Ensure that prescribed fires are burned at a low enough intensity and at a burn rate
such that the litter layer that remains behind is sufficient to protect the forest floor from
erosion after the fire. Also, do not set prescribed fires or allow prescribed fires to burn in
SMAs.
The presence of a litter layer on the forest floor is key to reducing and avoiding sediment runoff.
A low-intensity prescribed fire is more likely to leave an intact litter layer and reduce nutrient
runoff after a fire than a high-intensity fire.
Discussion
The importance of protecting the forest litter layer during forestry operations was stressed
earlier. Because exposure of bare forest soils is the critical link to sediment and nutrient runoff, it
is equally important to maintain the litter layer during and after a prescribed fire.
Studies have shown that low-severity prescribed fire removes the upper forest floor layer (the Oi
layer of the soil O horizon), but retains a large proportion of the portions of the O horizon below
that (the Oe and Oa horizon layers) (Knoepp et al. 2009). Those layers protect surface soils
from potential erosion and represent a large reservoir of plant nutrients.
Knoepp et al. (2009) investigated N responses on sites in subwatersheds that drained a first-
order stream in the Blue Ridge Physiographic province of the southern Appalachian Mountains.
All prescribed fires were done in the dormant season and were low to moderate intensity. All
sites lost a significant amount of forest floor mass due to burning: 82 to 91 percent of the Oi
layer and 26 to 46 percent of the Oe + Oa layer. Soil NH4~N concentrations increased
immediately after burning in the top 5 cm of surface soils only, but returned to pre-burn levels by
mid-summer. Burning had no measurable effect on soil solution inorganic N concentrations. No
inorganic N was lost from the sites (Knoepp et al. 2009).
Elliot and Vose (2005) conducted low- to moderate-intensity and low-severity prescribed burning
to restore shortleaf pine/mixed-oak forest (Elliot and Vose 2005). Fires of a low intensity in this
study were ones that left the Oe and Oa layers intact but reduced the uppermost litter layer (Oi),
exposed little soil, and had heat penetration only near the soil surface. They measured soil
Chapter 4. Forestry 4-33
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
solution and streamwater nutrient concentrations and streamwater sediment concentration
(TSS). Soil solution and stream water (N) did not increase after burning on any of the sites, and
they found no differences in TSS between the burn and control streams. No detectable
differences between control and burned sites for concentrations of PO4, SO4, Ca, Mg, K, or pH
in soil solution or stream water were found, either. The results suggest that low-intensity, low-
severity fires can be conducted and used as a management tool without negatively affecting
water quality (Elliot and Vose 2005).
2.8 Revegetation of Disturbed Areas
Implementation Measures:
F-15. Revegetate disturbed areas (using seeding or planting) promptly after
completing the earth-disturbing activity. Local growing conditions will
dictate the timing for establishing vegetative cover.
F-16. Use mixes of species and treatments developed and tailored for successful
vegetation establishment for the region or area. Native species are generally
preferred, although nonnative species can be acceptable as long as they are
noninvasive.
F-17. Concentrate revegetation efforts initially on priority areas such as disturbed
areas in SMAs or the steepest areas of disturbance (e.g., on roads, landings,
or skid trails) near drainages.
The 2005 forestry guidance describes the Revegetation of Disturbed Areas implementation
measure, and the practices provided in the 2005 are still the best advice for quickly restoring
vegetation on disturbed forest areas. This document provides no additions to the information in
the 2005 guidance. Revegetating disturbed areas is still important because it restabilizes the
soil, reduces erosion, and helps prevent pollutants from entering surface waters. As knowledge
of the ecological damage that can be caused by nonnative species has expanded after
numerous unsuccessful introductions of nonnative species for erosion control or other purposes,
it must be emphasized, however, that native species are preferred for revegetating disturbed
areas and any species used, whether native or nonnative, should be noninvasive for the habitat
into which it is to be introduced. Local or regional offices of a cooperative extension service can
offer excellent advice on species selection for revegetation uses.
4-34 Chapter 4. Forestry
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
2.9 Forest Chemical Management
Implementation Measures:
F-18. Establish and identify buffer areas for surface waters. (This is especially
important for aerial applications.) Conduct applications by skilled and,
where required, licensed applicators according to the registered use, with
special consideration given to effects on nearby surface waters. Carefully
prescribe the type and amount of pesticides appropriate for the insect,
fungus, or herbaceous species.
F-19. Before applying pesticides and fertilizers, inspect the mixing and loading
process and the calibration of equipment, and identify the appropriate
weather conditions, the spray area, and buffer areas for surface waters.
Immediately report accidental spills of pesticides or fertilizers into surface
waters to the appropriate state agency. Develop an effective spill
contingency plan to contain spills.
The 2005 forestry guidance describes the Forest Chemical Management implementation
measure. This document provides no additions to the information in the 2005 guidance.
Chemicals used in forest management include pesticides (insecticides, herbicides, and
fungicides) and fertilizers. Mixing, transporting, and applying the chemicals correctly and
according to manufacturer directions, and disposing of containers properly will prevent water
quality issues related to those substances to a great degree. For information relevant to forest
chemical management, see the 2005 guidance.
2.10 Wetlands Forest Management
Implementation Measure F-20:
Plan, operate, and manage normal, ongoing forestry activities (including harvesting;
road design, construction, and maintenance; site preparation and regeneration; and
chemical management) to adequately protect the aquatic functions of forested
wetlands.
The 2005 forestry guidance describes the Wetlands Forest Management implementation
measure. This document provides no additions to the information in the 2005 guidance. The
2005 guidance discusses special harvesting methods for use in forested wetlands, road design
and construction practices especially applicable to forested wetlands, wetland crossing
Chapter 4. Forestry 4-35
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
practices, site generation and regeneration practices for use in forested wetlands, fire
management practices for forested wetlands, and chemical management for working in forested
wetlands. The information provided in the 2005 guidance is still EPA's official guidance for
forestry work in wetland environments.
4-36 Chapter 4. Forestry
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
3 References
Akay, A.E., H. Oguz, I.R. Karas, and K. Aruga. 2009. Using LiDAR technology in forestry
activities. Environ. Monit. Assess. 151:117-125. [Akay et al. 2009 -> 2009a]
Allison, C., R.C. Sidle, and D. Tait. 2004. Application of decision alanlysis to forest road
deactivation in unstable terrain. Environ. Manag. 33(2): 173-185.
Aruga, K. 2005. Tabu search optimization of horizontal and vertical alignments of forest roads.
J. For. Res. 10:275-284.
Aruga, K., J. Sessions, and E.S. Miyata. 2005a. Forest road design with soil sediment
evaluation using a high-resolution DEM. J. For. Res. 10:471-479.
Aruga, K., J. Sessions, and A.E. Akay. 2005b. Heuristic planning techniques applied to forest
road profiles. J. For. Res. 10:83-92.
Baker, M.E., D.E. Weller, and I.E. Jordan. 2007. Effects of stream map resolution on measures
of riparian buffer distribution and nutrient retention potential. Landscape Ecology 22:973-
992.
Blankenship, K. 2006. State of the Chesapeake forests: Public perception often fails to look at
importance of forests beyond trees. .
Accessed April 22, 2010.
CBP (Chesapeake Bay Program). 1999. The State of the Chesapeake Bay. CBP/TRS 222/108.
.
Accessed February 8, 2010.
CBP (Chesapeake Bay Program). 2003. Expanded Riparian Forest Buffer Goals. Chesapeake
Executive Council. Directive No. 03-01.
. Accessed February
8, 2010.
CBP (Chesapeake Bay Program). 2004. Bay Watershed Forest Cover.
http://www.chesapeakebay.net/status watershedforests.aspx?menuitem=26067.
Accessed April 22, 2010.
CBP (Chesapeake Bay Program). 2008. New Conservation Goals Aim to Protect More
Chesapeake Forests. http://www.chesapeakebay.net/forests.aspx?menuitem=14640.
Accessed February 8, 2010.
Chapter 4. Forestry 4-37
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
CBP (Chesapeake Bay Program). 2009a. Bay Barometer. A Health and Restoration
Assessment of the Chesapeake Bay and Watershed in 2008. CBP/TRS 293-09. EPA-903-
R-09-001. .
Accessed February 8, 2010.
CBP (Chesapeake Bay Program). 2009b. Bay Health and Restoration Assessment.
. Accessed
Februarys, 2010.
Chung, W., J. Stuckelberger, K. Aruga, and T.W. Cundy. 2008. Forest road network design
using a trade-off analysis between skidding and road construction costs. Can. J. For. Res.
38:439-448.
Contreras, M., and W. Chung. 2007. A computer approach to finding an optimal log landing
location an analyzing influencing factors for ground-based timber harvesting. Can. J. For.
Res. 37:276-292.
Croke, J.C., and P.B. Hairsine. 2006. Sediment delivery in managed forests: a review. Environ.
Rev. 14:59-87.
Croke, J., S. Mockler, P. Fogarty, and I. Takken. 2005. Sediment concentration changes in
runoff pathways from a forest road network and the resultant spatial pattern of catchment
connectivity. Geomorphology 68:257-268.
CWP (Center for Watershed Protection). No date. The economic connections between forests
and drinking water: A pilot study in the Linganore Creek watershed, Maryland. Center for
Watershed Protection. Ellicott City, MD.
Eastaugh, C.S., P.K. Rustomji, and P.B. Hairsine. 2007. Quantifying the altered hydrologic
connectivity of forest roads resulting from decommissioning and relocation. Hydro/.
Process. 22:2438-2448.
Elliot, K.J., and J.M. Vose. 2005. Initial effects of prescribed fire on quality of soil solution and
streamwater in the Southern Appalachian Mountains. S. J. Applied For. 29(1):5-15.
Epstein, R., A. Weintraub, P. Sapunar, E. Nieto, J.B. Sessions, J. Sessions, F. Bustamante, and
H. Musante. 2006. A combinatorial heuristic approach for solving real-size machinery
location and road design problems in forestry planning. Operations Research 54(6): 1017-
1027.
Federal Leadership Committee. 2010. Strategy for Chesapeake Bay Watershed Protection and
Restoration. Chesapeake Bay Program, Annapolis, MD.
4-38 Chapter 4. Forestry
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
Fu, B., L.T.H. Newham, and J.B. Field. 2007. Modelling erosion and sediment delivery from
unsealed roads in southeast Australia. Mathematics and Computers in Simulation
79:2679-2688.
Ghaffarian, M.R., and H. Sobhani. 2007. Modelling erosion and sediment delivery from
unsealed roads in southeast Australia. Croat. J. For. Eng. 28(2): 185-193.
Hodges, C., and R. Visser. 2004. Comparison ofStreamside Management Zone Requirements
in the Southeast. Virginia Polytechnic Institute and State University, Department of
Forestry, Blacksburg, VA.
Homyak, P.M., R.D. Yanai, D.A. Burns, R.D. Briggs, and R.H. Germain. 2008. Nitrogen
immobilization by wood-chip application: Protecting water quality in a northern hardwood
forest. For. Ecol. Manag. 255:2589-2601.
Hotta, N., T. Kayama, and M. Suzuki. 2007. Analysis of suspended sediment yields after low
impact forest harvesting. Hydro/. Process. 21:3565-3575.
Klapproth, J.C., and J.E. Johnson. 2000. Understanding the science behind riparian forest
buffers: Effects on water quality. Pub. 420-151. Virginia State University, Virginia
Cooperative Extension, Petersburg, VA.
Knoepp, J.D., K.J. Elliott, B.D. Clinton, and J.M. Vose. 2009. Effects of prescribed fire in mixed
oak forests of the southern Appalachians: forest floor, soil, and soil solution nitrogen
responses. J. Torrey Bot Soc. 136(3):380-391.
Kyker-Snowman, T. No date. Forests and water: Some principles of management.
. Accessed March 2,
2010.
Lauren, A., H. Koivusalo, A. Ahtikoski, T. Kokkonen, and L. Finer. 2007. Water protection and
buffer zones: How much does it cost to reduce nitrogen load in a forest cutting? Scand. J.
For. Res. 22:537-544.
Loggertraining. 2010. Pennsylvania Timber Harvester/Forest Practitioner Training Program.
. Accessed March 4, 2010.
Lovett, G.M., K. Weathers, and M. Arthur. 2002. Control of nitrogen loss from forested
watersheds by soil carbon:nitrogen ratio and tree species composition. Ecosystems
5:712-718.
Mercker, D.C., and D.G. Hodges. 2007. Forest certification and nonindustrial private forest
landowners: Who will consider certifying and why? J of Extension 45(4).
. Accessed March 2, 2010.
Chapter 4. Forestry 4-39
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
Najafi, A., H. Sobhani, A. Saeed, M. Makhdom, and M.M. Mohajer. 2008. Planning and
assessment of alternative forest road and skidding networks. Croat. J. For. Eng.
29(1):63-73.
Neary, D.G., G.G. Ice, and C.R. Jackson. 2009. Linkages between forest soils and water quality
and quantity. Forest Ecology and Management 258:2269-2281.
NYLT (New York Logger Training). 2010. What is NYLT?
. Accessed March 4, 2010.
Rackley, J., and W. Chung. 2008. Incorporating forest road erosion into forest resource
transportation planning: a case study in the mica creek watershed in northern Idaho.
Trans. X\SX\6£51(1):115-127.
Rivenbark, B.L., and C.R. Jackson. 2004. Concentrated flow breakthroughs moving through
silvicultural streamside management zones: Southeastern Piedmont, USA. JAWRA
40(4): 1043-1052.
SFI (Sustainable Forestry Initiative). 2010. SFI2010-2014 Standard. Sustainable Forestry
Initiative, Inc., Washington, DC.
Sheridan, G.J., P.J. Noske, R.K. Whipp, and N. Wijesinghe. 2006. The effect of truck traffic and
road water content on sediment delivery from unpaved forest roads. Hydro/. Process.
20:1683-1699.
Spence, B.C, G.A. Lomnicky, R.M. Hughes and R.P. Novitski. 1996. An ecosystem approach to
salmonid conservation. TR-4501-96-6057. ManTech Corp, Corvalis, OR. Funded by
National Marine Fisheries Service, U.S. Fish and Wildlife Service and the U.S.
Environmental Protection Agency. Available from National Marine Fisheries Service,
Portland, OR.
SUNY (State University of New York). 2010. How does Forest Harvesting Affect Nitrogen in
Streams? State University of New York, College of Environmental Science and Forestry.
. Accessed March 2, 2010.
Takken, I., J. Croke, and P. Lane. 2008. A methodology to assess the delivery of road runoff in
forestry environments. Hydro/. Process. 22:254-264.
University of Florida. 2007. Forest Certification Programs.
. Accessed March 2, 2010.
USEPA (U.S. Environmental Protection Agency). 2005. National Management Measures to
Control Nonpoint Sources of Pollution from Forestry. EPA 841-B-05-001. U.S.
Environmental Protection Agency, Office of Water, Washington, DC.
4-40 Chapter 4. Forestry
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
USEPA (U.S. Environmental Protection Agency). 2008. Virginia 2008 Water Quality
Assessment Report. U.S. Environmental Protection Agency, Office of Water, Washington,
DC. . Accessed March
4, 2010.
Virginia Tech. 2010. SHARP Logger Program, . Accessed
March 4, 2010.
White, W.J., LA. Morris, A.P. Pinho, C.R. Jackson, and LT. West. 2007. Sediment retention by
forested filter strips in the Piedmont of Georgia. J. Soil Water Cons. 62(6):453^63.
Wlliams, T.M., D.J. Lipscombb, W.R. English, and C. Nickel. 2003. Mapping variable—width
streamside management zones for water quality protection. Biomass and Bioenergy
24:329-336.
Wtmer, P.L., P.M. Stewart, and C.K. Metcalf. 2009. Development and use of a sedimentation
risk index for unpaved road-stream crossings in the Choctawhatchee watershed. JAWRA
45(3): 734-747.
WVDOF (West Virginia Division of Forestry). 2010. Logging. West Virginia Division of Forestry,
Charleston, WV. . Accessed March 4, 2010.
Chapter 4. Forestry 4-41
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
Chapter 5.
Riparian Area Management
Contents
1 Introduction 5-3
1.1 What is a Riparian Area? 5-3
1.2 Why Riparian Buffers? 5-4
1.3 Who is This Chapter For? 5-5
1.4 What Does This Chapter Cover? 5-5
2 Benefits of Natural Riparian Areas 5-6
2.1 Water Quality Benefits 5-7
2.1.1 Filtering Sediment Pollution 5-7
2.1.2 Filtering Nutrient Pollution 5-7
2.1.3 Estimated Pollutant Removal 5-8
2.2 Floodplains and Streambanks 5-10
2.3 Maintaining Aquatic Habitat 5-11
2.4 Aesthetic Value 5-12
2.5 Forested versus Grassed Buffers: Increased Focus on the Buffer/Stream
Interface 5-12
3 Restoring and Reestablishing Riparian Forest Buffers 5-13
3.1 Introduction 5-13
3.1.1 Organization of This Section 5-13
3.2 Selecting and Prioritizing Areas for Restoration 5-14
3.2.1 Stream Order 5-14
3.2.2 GIS Tools for Buffer Placement 5-16
3.3 Analyzing Existing Conditions and Identifying Potential Problems 5-17
3.3.1 Hydrology 5-17
3.3.2 Soils 5-17
3.3.3 Riparian Vegetation 5-18
Chapter 5. Riparian Area Management 5-1
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
3.3.4 Special Characteristics and Potential Problems Associated with a
Previous Land Use 5-19
3.4 Buffer Width and Connectivity 5-21
3.5 Establishing Riparian Vegetation 5-24
3.5.1 Natural Regeneration 5-24
3.5.2 Planting Trees 5-25
3.5.3 Protecting Seedlings 5-26
3.5.4 Reinforcement Planting 5-28
3.6 Cost 5-28
4 Protection and Maintenance of Riparian Areas 5-29
4.1 Background 5-29
4.2 Long-Term Maintenance 5-30
4.2.1 Watershed-Scale Evaluation 5-30
4.2.2 Evaluation of Buffer Quality 5-31
4.2.3 Managing Plants 5-33
4.3 Protection 5-36
4.3.1 Acquisition 5-37
4.3.2 Zoning and Protective Ordinances 5-37
4.3.3 Water Quality Standards 5-40
4.3.4 Regulation and Enforcement 5-40
4.3.5 Education and Training 5-41
5 References 5-42
5-2 Chapter 5. Riparian Area Management
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
1 Introduction
1.1 What is a Riparian Area?
A riparian area is defined as
A vegetated ecosystem along a waterbody through which energy, materials, and
water pass. Riparian areas characteristically have a high water table and are
subject to periodic flooding and influence from the adjacent waterbody. These
systems encompass wetlands, uplands, or some combination of those two
landforms. They will sometimes, but not in all cases, have all the characteristics
necessary for them to be also classified as wetlands (USEPA 2005).
In other words, riparian areas are the areas between uplands and adjacent waterbodies that
encompass the floodplain and some transitional upland area (Tjaden and Weber 1998). Both
soils and vegetation in riparian areas are usually distinctly different from the surrounding
uplands and typically support a diverse and unique population of animals as compared to
uplands. They act as natural filters of nonpoint source pollutants, including sediment, nutrients,
pathogens, and metals, to waterbodies such as rivers, streams, lakes, and coastal waters. The
term riparian buffer is used to distinguish a specific area adjacent to the stream within a riparian
area (see Figure 5-1) or, in some cases, it might include the entire area. Riparian buffers can
also be referred to as riparian management zones, buffer strips, and streamside management
zones.
Figure 5-1. Relationship between uplands, riparian areas, riparian buffers, and the stream channel.
Chapter 5. Riparian Area Management
5-3
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
Riparian areas are inextricably linked to the stream itself. Disturbances that affect the riparian
area affect the stream and vice versa. Stream corridor \s a term used to describe the combined
riparian/stream ecosystem (FISRWG 1998). Stream corridors in the Chesapeake Bay region
evolved within temperate, forested watersheds (Williams 1989). Thus, system structure,
functions, and biota in the corridor all developed within a range of natural conditions associated
with forest ecosystems. For that reason, management plans aimed at restoring streams to more
natural state typically focus on restoring and protecting riparian forest buffers.
1.2 Why Riparian Buffers?
Riparian buffers (Figure 5-2) can significantly aid in
reducing pollution contributions to the Chesapeake Bay,
including nitrogen (N), phosphorus (P), and sediments.
They also contribute to the protection of streams and
streambanks and provide habitat for a multitude of
species. Ideally, a network of buffers along a stream can
act as a natural right-of-way, allowing the stream to move
through the landscape buffered from direct influences of
development in the watershed. Riparian forested buffers
in particular have long been recognized as a vital part of
the Chesapeake Bay ecosystem. For those reasons, the
U.S. Environmental Protection Agency (EPA) considers
the protection and restoration of riparian buffers to be a
critical element of the Chesapeake Bay Program.
Riparian Buffer Goal for the Chesapeake Bay:
Forest buffers should exist on at least 70 percent of
all shorelines and streambanks in the watershed.
Figure 5-2. A riparian buffer.
The Chesapeake Executive Council adopted the 70 percent riparian buffer goal for the Bay in
2003 (Chesapeake Executive Council 2003). EPA reiterates that goal in this guidance. An
interim goal to achieve 63 percent by 2025 was adopted as part of the Chesapeake Bay
Strategy under the Executive Order.
Approximately 58 percent of the Bay's riparian areas are forested. To reach both the interim
goal of 63 percent and long-term goal of 70 percent coverage in the entire watershed, the
Chesapeake Bay Program and its partners will need to restore at least 30,000 miles of riparian
buffers and conserve all riparian areas that are forested. The following two implementation
measures for riparian buffers will enable the forested riparian buffer goals to be met.
5-4
Chapter 5. Riparian Area Management
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
Implementation Measures:
R-l. Promote the restoration of the preexisting functions in damaged and
destroyed riparian systems, especially in areas where the systems will serve
a significant nonpoint source pollution-abatement function as well as the
suite of valuable ecosystems services riparian buffers provide.
R-2. Protect from adverse effects riparian areas that are serving a significant
nonpoint source pollution-abatement function and maintain this function
while protecting the other existing functions of these riparian areas.
The measures are in line with past EPA guidance (USEPA 2005) as well those described in the
National Research Council report Riparian Areas: Functions and Strategies for Management in
2002 (NRC 2002). Specifically, that restoration of riparian functions along America's
waterbodies should be a national goal and protection should be the goal for riparian areas in the
best ecological condition.
1.3 Who is This Chapter For?
This chapter of the guidance document is written for federal land managers who manage
riparian areas. EPA anticipates that it will be useful for others involved in watershed planning,
including conservation districts, local municipalities landowners, and land use managers, total
maximum daily load developers, conservation trusts, and natural resource contracts specialists.
1.4 What Does This Chapter Cover?
This chapter has three main sections:
• Section 2 describes the benefits of buffers, including pollutant-removal efficiency and
factors that affect it.
• Section 3 outlines recommendations for the restoration of forested buffers in the
Chesapeake Bay and includes site selection, planting, and short-term maintenance of
newly restored sites.
Section 4 discusses strategies for the long-term maintenance and the protection of existing
forested riparian areas. Such areas must first be identified and assessed before they can be
properly maintained and protected.
Chapter 5. Riparian Area Management 5-5
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
2 Benefits of Natural Riparian Areas
Many benefits are associated with forested riparian areas. Some of those benefits can be
replicated with technology such as reservoirs (flood control) and treatment plants (pollutant
removal). However, none of those single-function replacement technologies provide the
multiple, simultaneous functions of a healthy forested riparian area.
This section describes a few of the most important of the many benefits. In general, benefits can
be categorized into one or more of six broad ecological functions (FISRWG 1998) (Figure 5-3):
• Barrier and Filter—The ability to stop or limit penetration of water, materials, energy, and
organisms into, through, or along the stream corridor
• Habitat—The spatial structure of the riparian area and stream, which allows organisms
to live, feed, and reproduce
Habitat—the spatial structure
of the environment which
allows species to live,
reproduce, feed, and move.
Filter-the selective
penetration of materials,
energy, and organisms.
Habitat
Filter
Barrier—the stoppage of
materials, energy, and
organisms.
Source—a setting where
the output of materials,
energy, and organisms
exceeds input.
Barrier
Source
Conduit-the ability of the
system to transport materials,
energy, and organisms.
Conduit
Source: FISRWG 1998
Figure 5-3. Critical ecosystem functions.
Sink
Sink—a setting where the
input of water, energy,
organisms and materials
exceeds output.
5-6
Chapter 5. Riparian Area Management
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
• Conduit—The ability of the corridor to serve as a flow pathway for water, materials,
energy, and organisms
• Source and Sink—The net movement of water, materials, energy, and organisms in or
out of the buffer
2.1 Water Quality Benefits
2.1.1 Filtering Sediment Pollution
Erosion, transport, and deposition of various-sized soil particles from the watershed into the
stream channel are natural processes that shape the landscape over time. Those processes are
disturbed by human activities such as urban development and agriculture. The exposure of soil
during construction, because of overgrazing or between growing seasons, combined with the
increased surface runoff associated with increased impervious surfaces and soil compaction
increase sediment loading to streams. That causes a variety of negative in-stream effects,
including the following:
• Destroying beneficial channel structures such as pool and riffles
• Damaging gills of fish and aquatic insects
• Filling in pore spaces on the stream bed and suffocating benthic biota
• Interfering with fish spawning habitat, and egg and larval survival
• Reducing light penetration and interfering with algae and aquatic plant photosynthesis
Riparian areas help regulate the amount and size of sediment that reaches the stream from
upland sources. Assuming that sediment-laden runoff moving through the riparian area is not
allowed to concentrate, channelize, and convey directly to the stream, sediment will be
deposited as riparian vegetation slows runoff and water infiltrates the soil.
2.1.2 Filtering Nutrient Pollution
N and P are two nutrients essential for the growth of algae and other aquatic plants. When
present in excessive amounts, however, they can trigger algal blooms, nuisance levels of plant
growth, and overall degradation of a stream. Altering land use for human activity has greatly
increased the amount of nutrients in aquatic systems. Those excess nutrients come from lawn
and agricultural fertilizers, animal wastes, sewage treatment plants, and septic systems. The
potential pathways to a stream of the two nutrients differ, however, because of different
chemical properties. Correspondingly, the filtering mechanisms for P and N within riparian areas
also differ.
Chapter 5. Riparian Area Management 5-7
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
P has a strong tendency to sorb to soil particles and organic matter. Therefore, it is usually
moved across the landscape attached to sediment that is carried in surface runoff.
Consequently, the conditions and mechanisms that serve to filter out sediments in riparian
areas serve to filter out P. As sediment settles from runoff and water infiltrates the soil, the
attached P can either remain in the soil or be taken up by riparian vegetation.
On the other hand, N does not sorb strongly to sediment. While N in particulate form can be
physically filtered by vegetation, similar to sediments, nitrate in dissolved form can infiltrate the
soil, move with groundwater, and potentially enter the channel with shallow subsurface flow or
baseflow.
Bacteria residing in riparian soils play an important role in filtering N through a process called
denitrification. That process reduces nitrate to primarily dinitrogen gas (N2) with possible
production of trace amounts of nitrous oxide, a potent greenhouse gas, both of which are
released into the atmosphere. The basic requirements for denitrification are anaerobic
conditions or restricted oxygen availability (saturated soil conditions), a good supply of nitrate
and electron donors such as organic material, and warm conditions (above 50 degrees
Fahrenheit [°F]). Other microorganisms and biota in the soil take up N, as do plants if the root
zone is saturated part of the time.
2.1.3 Estimated Pollutant Removal
The Mid-Atlantic Water Program at the University of Maryland led a project in 2006-2007 to
review and refine definition and effectiveness estimates for best management practices (BMPs)
in the Chesapeake Bay watershed, including grassed and forested riparian buffers in
agricultural areas. The objective was to develop estimates that reflect the average operational
condition representative of the entire watershed to better reflect monitored data in modeling
scenarios and watershed plans. Table 5-1 summarizes the nutrient and sediment reduction
efficiencies for forest and grass buffers in agricultural areas on the basis of the literature review
performed for this study. As indicated by the results, forest buffers are better at reducing N
loads to the Chesapeake Bay; however, forest and grass buffers are the same in their ability to
reduce P and sediment loads.
5-8 Chapter 5. Riparian Area Management
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
Table 5-1. Average nutrient and sediment reduction efficiency comparison of riparian forest and
grass buffers
Location
Inner Coastal Plain
Outer Coastal Plain Well Drained
Outer Coastal Plain Poorly Drained
Tidal Influenced
Piedmont Schist/Gneiss
Piedmont Sandstone
Valley and Ridge — marble/limestone
Valley and Ridge — sandstone/shale
Appalachian Plateau
TN reduction (%)
Forest
65%
31%
56%
19%
46%
56%
34%
46%
54%
Grass
46%
21%
39%
13%
32%
39%
24%
32%
38%
TP reduction (%)
Forest
42%
45%
39%
45%
36%
42%
30%
39%
42%
Grass
42%
45%
39%
45%
36%
42%
30%
39%
42%
TSS reduction (%)
Forest
56%
60%
52%
60%
48%
56%
40%
52%
56%
Grass
56%
60%
52%
60%
48%
56%
40%
52%
56%
Source: Simpson and Weammert 2009
Note: TN = total nitrogen; TP = total phosphorus;
TSS = total suspended solids
It is important to remember that all buffers do not have the same efficiency for pollutant
reduction (Speiran et al. 1998). Pollutant-removal estimates in Table 5-1 are based on average
conditions in agricultural areas and were developed for use in EPA's Chesapeake Bay Water
Quality Model. Research on pollutant removal in urban and suburban areas is limited. In
addition, site-specific conditions can greatly affect pollutant-removal processes. Hot spots,
regions of disproportionately high reactions rates compared to the surrounding area, or hot
moments, short periods when disproportionately high reaction rates occur compared to typical
conditions, can occur and alter annual contaminant budgets at the watershed scale (Vidon et al.
2010).
Hydrology plays a significant role in buffer effectiveness. The filtering functions of a buffer are
greatly reduced when runoff enters the riparian area as concentrated flow or channelizes while
flowing through the buffer. Denitrification in riparian zones is affected by the depth of the water
table and the presence of subsurface carbon and dissolved oxygen in groundwater. Pollutant
removal is reduced where ideal conditions do not occur. For example, in urban areas, surface
runoff is usually diverted into a stormwater management system that conveys water directly into
streams. Similar short circuiting occurs in agricultural areas that are tile drained. In those
situations, runoff completely bypasses riparian buffers and does not receive any of their
pollutant-removal benefits.
Because of those and other factors, pollutant source control, discussed in the other chapters of
this document, is extremely important in addition to the use of riparian forest buffers for water
quality.
Chapter 5. Riparian Area Management
5-9
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
The U.S. Department of Agriculture (USDA) Agricultural Research Service Southwest
Watershed Research Laboratory developed the Riparian Ecosystem Management Model
(REMM), for researchers and natural resource agencies to help quantify the water quality
benefits of riparian buffers under varying site conditions. REMM requires weather data, pollutant
input information, riparian soils, vegetation, and litter information and is calibrated only for the
Coastal Plain in Georgia, but it would be useful in areas with similar conditions where the
required input parameters are available.
2.2 Floodplains and Streambanks
During intense storms, water levels in the stream can rise above bankfull elevation and spill into
the hydrologic floodplain. Flooding is important because it reconnects the floodplain to the
stream and provides habitat conditions critical for the reproductive cycle of some species of fish,
insects, amphibians, and reptiles. Increased impervious surfaces or compacted soils associated
with urban development in a watershed increases flow energy in streams, which can cause
greater rates of streambank erosion. That erosion can become so significant that even with the
increased runoff entering the stream, the stream becomes incised and completely disconnected
from its floodplain.
The presence of a healthy riparian area can mitigate the effects of such altered hydrology. One
study found that vegetation restoration of bare ground and livestock trampled riparian zones
reduced catchment export of sediment from over 100 kilograms per hectare per year to less
than 10 within one year, mainly by reducing bank erosion and stabilizing the stream channel
(McKergow et al. 2003).
Woody riparian vegetation in the floodplain serves to dissipate flow energy during floods. Root
systems of riparian vegetation immediately adjacent to the stream help bind sediments, which
can reduce bank erosion. Riparian forests contribute large woody debris to streams, such as
branches, logs and root wads. The roughness they create in the channel can slow stream
velocity, which promotes channel bed and bank stability and sediment deposition (Harmon et al.
1986). Dams created by the debris can also increase sediment deposition in channels and
increase flooding frequency that promotes sediment deposition on floodplains (Dosskey et al.
2010). Deposition of sediment also removes sediment-bound chemicals (such as P) and soil
organic matter from the water column, which in turn contributes to biogeochemical processes in
floodplains and the stream channel.
5-10 Chapter 5. Riparian Area Management
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
2.3 Maintaining Aquatic Habitat
Stream biota, including bacteria, algae, macrophytes, zooplankton, macroinvertebrates, fish,
amphibians, reptiles, and mammals, all require a hospitable aquatic environment to live,
reproduce, interact, and thrive. The riparian area plays a crucial role in maintaining a range of
suitable habitats and conditions within the channel for a diverse and self-sustaining cycle of
aquatic life. Good quality terrestrial habitat is essential for maintaining water quality and natural
flows in the stream channel.
As discussed in Section 1 of this chapter, a riparian area usually includes the streambank,
floodplain, and some portion of the transitional upland area. Natural features within such areas
add structural variety and might include wetlands, natural levees, oxbow lakes, and other
landforms. Diversity of riparian features usually results in corresponding diversity in soils,
vegetation, and biota—important attributes of a healthy terrestrial habitat.
A few important benefits of forested riparian areas for habitat are described below.
• Contributing wood debris to the channel—Large, woody debris that falls into the channel
creates additional habitat diversity for fish and other aquatic biota, especially in smaller
streams. They often create a damming effect that traps sediment and create scour holes
and function as fish habitat.
• Provides allochthonous input of organic matter—Energy sources that drive metabolic
activity in a stream come from either autochthonous sources (within the stream channel
via algae and aquatic plant photosynthesis) or allochthonous sources (outside the
stream channel). In smaller, shaded headwater streams, there is little aquatic primary
production because of lower light levels. Here, allochthonous input of woody material,
leaves, and other organic matter is critical for the base of the food chain. Bacteria and
fungi break the material down, and their microbial biomass becomes food for shredding
invertebrates. Organic particles are subsequently transported to provide energy for
downstream organisms.
• Maintaining stream temperature—Water temperature determines the range and viability
of aquatic species. Some species, such as trout, require cold water temperatures. Other
species, such as smallmouth bass, tolerate warmer temperatures. Riparian vegetation
that covers the channel reduces solar radiation and keeps water temperatures cooler.
Baseflow (from groundwater inflow) helps keep water temperatures stable year round.
Chapter 5. Riparian Area Management 5-11
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
2.4 Aesthetic Value
Besides water quality and habitat benefits, riparian areas can add value to property providing
seasonal changes, such as shade in summer, flowers and birds in spring, and color in fall (Baird
and Wetmore 2003). A study in 2006 in Missouri found that residents are willing to pay to live in
an area with community owned and accessible buffers, and are willing to pay even more to live
adjacent to these areas (Qiu et al. 2006). That pattern is consistent with other studies (Patterson
and Boyle 2005; Netusil 2006).
2.5 Forested versus Grassed Buffers: Increased Focus
on the Buffer/Stream Interface
Sweeney and Elaine (2007) point out that buffers have been historically viewed almost
exclusively in terms of their barrier and filter functions; specifically, their ability to filter out upland
sediment, nutrients, and other pollutants before they reach the channel. Such a focus on the
upland/buffer interface resulted in a general acceptance of grass buffers as a reasonable
alternative to forested buffers, because some studies show similar pollutant removal
efficiencies. For cultural, sociological, budgetary, and other reasons, grass buffers were even
sometimes promoted as the preferred choice for riparian vegetation.
Research in the past decade, however, has revealed that grass buffers are about 68 percent as
effective as forest buffers in reducing total nitrogen (TN) (Todd 2002). But perhaps more
significant, the positive effects that riparian forest buffers have on stream systems have been
more fully explored and documented. Sweeney (1992, 1993) reinforced the idea that stream
processes, functions, and biota were developed in concert with riparian forests rather than
riparian grasslands, and the absence of trees creates considerable stress on the natural aquatic
ecosystem. For example, a study of forested and deforested small streams in the Piedmont
region demonstrated that deforestation caused significant channel narrowing which, in turn,
reduced stream habitat and processing of organic matter and nutrients (Sweeney et al. 2004).
The study also determined that a forested stream ecosystem had 2 to 10 times more uptake of
N than a grass ecosystem. For those reasons, this chapter focuses on forested riparian buffers.
That is not to say that upland/buffer interface is not an important consideration for buffer design,
because that is where most sediment deposition and a lot of biogeochemical removal occurs.
However, the buffer/stream interface must not be overlooked.
5-12 Chapter 5. Riparian Area Management
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
3 Restoring and Reestablishing Riparian Forest
Buffers
Implementation Measure R-1:
Promote the restoration of the preexisting functions in damaged and destroyed
riparian systems, especially in areas where the systems will serve a significant
nonpoint source pollution-abatement function as well as the suite of valuable
ecosystems services riparian buffers provide.
3.1 Introduction
Approximately 58 percent of the streams in the Chesapeake Bay have riparian forest buffers,
short of the 2025 goal of 63 percent, and the long-term goal of 70 percent. That means that
restoring or reestablishing riparian forests is required to meet the Bay goal. Maryland, Virginia,
Pennsylvania, and the District of Columbia have proposed in their tributary strategies to restore
some 50,000 miles of riparian forest buffers to help reach water quality goals for major rivers
that drain into the Bay (Greiner and Vogt 2009).
Successful restoration and reestablishment of buffers in the Chesapeake Bay area require that
landowners, managers, public agencies, and other responsible parties assess ecological
functions provided by existing riparian soils and vegetation and then make the best adjustments
and improvements possible given cost, funding, and other practical constraints. In many cases,
restoration will include planting seedlings and eventually reestablishing fully functioning riparian
forest.
3.1.1 Organization of This Section
This section is organized to cover the basic steps for undertaking a successful riparian forest
buffer restoration project.
• Selecting and prioritizing areas for restoration (Section 3.2)
• Analyzing existing conditions and identifying potential problems at the site level
(Section 3.3)
• Importance of connectivity and determining the appropriate buffer width (Section 3.4)
• Selecting, planting, and protecting tree seedlings (Section 3.5)
Chapter 5. Riparian Area Management 5-13
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
Much of the information presented in Sections 3.2 and 3.4 are based on the Maryland
Department of Natural Resources Forest Service (DNR FS) manual, Riparian Forest Buffer
Design and Maintenance (2005). For details about the methods and procedures described, see
that manual.
Sections 3.6 and 3.7 wrap up the chapter by discussing costs of riparian buffer restoration, and
present information on potential sources of funding.
3.2 Selecting and Prioritizing Areas for Restoration
As discussed in Section 2.1, to get certain pollutant-removal benefits, riparian buffers must
intercept pollutants. While seemingly obvious, it is usually easier said than done. While it is easy
to identify areas where runoff would bypass riparian buffers, such as areas with stormwater
outlet pipes and gullies, other factors are less obvious. A few studies have found that
groundwater seeps due to macropores from roots can also reduce buffer effectiveness and
have a significant effect on stream chemistry (O'Driscoll and DeWalle 2010; Angier and McCarty
2008). Identifying those conditions is expensive and time consuming, and it is not possible on
every riparian restoration site. Fortunately, land managers can use information such as stream
order and geographic information system (GlS)-based data analysis tools to locate areas where
maximum pollutant-removal benefits are most likely.
3.2.1 Stream Order
As a mainstem stream moves through its watershed, it drains an increasing amount of land
area. The mainstem stream is continuously fed by a network of feeder streams. Strahler (1957)
proposed a classification system to identify the position of all streams in a watershed network.
Small streams with no tributaries are first-order streams (Figure 5-4). When two first-order
streams flow together, they become a second-order stream. The confluence of two second-
order streams creates a third-order stream, and so on.
Lower order streams dominate the landscape in terms of numbers and stream mileage. It is
estimated that 75 percent of streams in the United States are first- and second-order streams
and 90 percent are first-, second-, or third-order streams (FISRWG 1998; Leopold et al. 1964).
Therefore, meeting the short- and long-term goals for forested riparian buffer coverage in the
Chesapeake Bay watershed requires managers to focus primarily on restoring buffers of lower
order streams.
5-14 Chapter 5. Riparian Area Management
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
Figure 5-4. Strahler's stream classification.
The relatively small scale of headwater streams also increases the magnitude of influence the
riparian area has on them (Sweeney and Elaine 2007). A forest canopy, for example, can easily
extend across small streams and keep stream temperature cool. Large, woody debris adds
proportionally more structure to the channel, and allochthonous materials are distributed
throughout the channel and support life in virtually all microhabitats.
Because a small stream's watershed is also smaller in size, a forest buffer of even modest
proportions can effectively regulate the lateral flow of water and filter a commensurate volume of
sediments, P, and other pollutants (Dosskey et al. 2005; Polyakov et al. 2005). Groundwater
flow is usually shallower and therefore more likely to pass within the root zone of trees as it
travels downslope. That increases the opportunity for N uptake before groundwater flow
reaches the channel (Craig et al. 2008). In addition, as stream order increases, direct surface
runoff to the channel tends to increase, meaning that in smaller watersheds, a greater
proportion of upland runoff will actually be intercepted by the riparian zone (McGlynn and
Seibert 2003; Tomer et al. 2003; Wondzell and Swanson 1996).
Chapter 5. Riparian Area Management
5-15
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
3.2.2 CIS Tools for Buffer Placement
Stream order is only one factor in determining where buffers might have the most influence on
water quality. Upland nutrient loading, depth to water table, and slope are some of the many
factors that land managers should take into account to prioritize areas for restoration in terms of
maximum pollutant-removal benefit. Several GIS tools are being developed to synthesize the
information and identify critical areas where buffers are most needed in terms of water quality
benefit. One example is the Chesapeake Bay Riparian Forest Buffer Targeting Scheme.
Riparian Forest BufferTargetingScheme
Anne Arundel County, MD
'MARYLAND
In 2008 the Chesapeake Bay
Forestry Workgroup developed a
scientifically based scheme to
identify areas in the watershed
where performance of riparian forest
buffers might be expected to be
high. The scheme is in the form of a
targeting matrix that captures the
variables that influence the
efficiency of nutrient removal in a
buffer, namely, hydrology
(specifically depth to water table),
slope, land use, and source nutrient
loading.
Each of the attributes is weighted
according to importance and then
scored, with a higher score given to
conditions that would result in more
pollutant removal (such as a shorter
depth to water table). The scores
are analyzed in GIS to create a map
like the one in Figure 5-5. For more
information on the matrix, including
an explanation of why the attributes
listed here are the most likely to
result in the successful placement of riparian forest buffers in areas of the Chesapeake Bay
watershed, see http://archive.chesapeakebay.net/pubs/calendar/FWG 11-18-
08 Handout 3 9152.pdf and http://archive.chesapeakebay.net/pubs/calendar/FWG 11-18-
08 Presentation 1 9152.pdf.
Buffer Target Priority
0-0.3B Lower
0.37-0.79
0 80 -1 00
1.01 - 1.36
1.37-1.5
1.51-1.79
> 1.80-193
1-94-2.21
2.22 - 2.57
2.58 - 4 Higher
N
Figure 5-5. Riparian Buffer Prioritization Map of Anne
Arundel County, Maryland.
5-16
Chapter 5. Riparian Area Management
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
3.3 Analyzing Existing Conditions and Identifying
Potential Problems
Every riparian forest buffer has a unique set of conditions that managers must understand
before developing a restoration plan. How those conditions link to pollutant removal and
ecological function is important to success. Three key areas that need to be addressed are (1)
hydrology, (2) soils, and (3) existing vegetation. In addition, special characteristics and potential
problems associated with converting a previous land use to a forest buffer should be
considered.
3.3.1 Hydrology
As discussed throughout this chapter, riparian areas are driven by hydrology (NRC 2002).
Identifying pathways of water flow through the site provides clues on how well beneficial
functions in the riparian area will operate once reforested. Ideal site hydrological conditions
include the following:
• Local groundwater originating from adjacent upland takes a relatively shallow path
through the soil and comes into contact with the root zone of buffer vegetation. That
contact increases the likelihood that N will be taken up by vegetation, immobilized by
microorganisms, or undergo denitrification by bacteria.
• Runoff water originating from the uplands does not concentrate, channelize, and convey
directly to the stream and bypass riparian vegetation and groundwater recharge areas.
Gently sloping vegetative landscapes are preferred because they promote sheetflow and
naturally reduce runoff velocity. These attributes increase the residence time of surface
runoff and increase the likelihood of infiltration. Lower slopes also tend to reduce the
velocity of groundwater flow and increase its contact time with buffer vegetation roots
and other processes that remove or immobilize N.
Hydrologic analysis at the site should include an evaluation on how well the above conditions
are met.
3.3.2 Soils
Success in regulating the lateral flow of water, filtering sediment and nutrient pollution, and
maintaining important processes and functions in the stream itself ultimately depends on
riparian soils and the organisms that reside in them. Features within the riparian area such as
natural levees and wetlands have their own unique soil characteristics. Soil complexity is
beneficial because different soil attributes affect the occurrence and efficiency of ecological
Chapter 5. Riparian Area Management 5-17
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
functions as well as supporting a diverse vegetative community (FISRWG 1998). Some
important soil characteristics to assess include the following:
• So/7 composition and texture—Soils are composed of various inorganic mineral particles
that can be categorized by size (sand, loam, or clay) and organic matter (in various
stages of decomposition). Soils that promote infiltration and transmission of water need
to have a high porosity, such as coarse-textured sandy/loamy soils held together with
organic matter, as opposed to fine-textured clayey soils.
• So/7 moisture—The ability of the upper layer of soil to hold water by surface tension in
fine pores is very important to the growth and survival of vegetation. Loamy/clayey soils
have the best water-holding properties. Sandy soils are the most porous and do not
have much capacity to hold water.
• So/7 compaction—Human activity, especially in urban areas, can compact natural soils
and reduce infiltration and water-holding capacity as well as killing root systems. About
50 percent pore space is ideal (MDNR FS 2005).
• Wetland soils—Wetlands in riparian areas typically occur where the water table is at or
near the surface. Soils are hydric, meaning they are saturated during all or portions of
the growing season and develop anaerobic conditions. Only plants adapted to these
conditions can survive in wetlands. Saturated areas are also important areas for
denitrification, a bacterial process that removes nitrate from groundwater before it
reaches the stream channel, and should be identified and protected.
The Pennsylvania Stream ReLEAF Forest Buffer Toolkit, section 2 of the Maryland DNR
Riparian Forest Buffer Design and Maintenance guide, and section 4 of the Chesapeake Bay
Riparian Handbook: a Guide for Establishing and Maintaining Riparian Forest Buffers (Palone
and Todd 1997) contain guidance on soil evaluation.
3.3.3 Riparian Vegetation
Soil properties, topography, shading, seed stock, water availability, and other factors determine
the density and distribution of vegetative species within a riparian area. Plants play an important
role in filtering, storing, and processing pollutants and lessening their effect on stream quality.
Riparian vegetation also performs several ecological functions. Restoring vegetative structure,
especially reestablishing trees, is often the most visible aspect of a riparian restoration project.
Different attributes affect the occurrence and efficiency of ecological functions. Important
characteristics that managers need to assess and then maintain or restore include the following:
• Trees adjacent to the stream—The importance of trees to stream ecology is discussed in
Section 2 of this chapter. The annual cycle of growth and senescence of trees provides
5-18 Chapter 5. Riparian Area Management
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
organic material to the stream, which serves as the base of the food chain in headwater
streams. Streamside trees also add large, woody material to the channel, which provides
important habitat functions for a variety of aquatic biota. Additionally, the root systems of
streamside trees help bind bank sediments and reduce the potential for erosion.
• Horizontal complexity—A riparian area with diverse population of vegetation is generally
a reflection of a diversity of soils, drainage conditions, flooding patterns, and other
conditions across the area. A mix of herbaceous plants, shrubs, and trees provide
varying levels of sediment, nutrient, and pollutant removal efficiencies (FISRWG 1998).
Complex vegetation habitat also typically results in a wider variety of wildlife.
• Edge habitat—Two distinct habitats within a riparian forest area are edge habitat and
interior habitat. The edge habitat is the area of transition between an upland ecosystem
and the interior forest. Compared to interior habitat, edge habitat, by virtue of its position,
receives higher and more fluctuating levels of solar and wind energy, precipitation, and
water and materials flowing from the adjacent land use. Therefore, it functions as the
first line of defense for regulating runoff and filtering pollutants. Flora and fauna that
inhabit edge habitat are species that can tolerate more intense and fluctuating
conditions.
• Interior habitat—Interior habitat is a more stable environment, sheltered from conditions
endured by edge vegetation. In general, more sensitive and rare species of plants and
animals are in interior habitat, away from the dynamic processes in the edge habitat.
Therefore, if protecting sensitive or rare species is an objective of riparian forest buffer
restoration, managers must ensure that there is adequate interior habitat in the buffer.
• Vertical complexity—Birds and other tree-dwelling wildlife depend on a variety of layers
of vegetation to thrive and reproduce. A vertically complex area also reflects a diversity
of age composition and indicates a successful pattern of succession and new growth.
3.3.4 Special Characteristics and Potential Problems Associated
with a Previous Land Use
If all or a portion of the riparian area being restored was used for some other purpose (e.g.,
cropland, pastureland, lawns, parkland), there might be special characteristics or potential
problems that should be assessed. As described in Riparian Forest Buffer Design and
Maintenance (2005), those could include the following:
• Compacted soils—Soil compaction is often a problem in developed areas. Compacted
soil restricts the movement of water into the ground and inhibits root penetration. It is
often a problem in urban and suburban soils because of vehicle or foot traffic, playing
areas, or other use. Compacted soils in pastureland might be due to cow paths or other
animal or equipment traffic. Usually soil compaction is not a problem in agricultural
Chapter 5. Riparian Area Management 5-19
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
lands; however, there might be a compacted layer of soil below the plow zone. If
compaction presents a problem for tree rooting, a moderate amount of discing or tilling
can be employed to loosen the soil.
• Fill material or other problem soils—Fill material, especially in suburban and urban
areas, might have been imported and placed on the site. Fill can contain any variety of
material not amenable for growth of native trees and vegetation. Conditions could
include low fertility, high sand content, high clay content, low organic matter content,
excessive rocks, and low microfauna content. Soil testing that includes composition and
pore analysis, pH, and organic and nutrient content can help determine soil limitations
and what amendments might be needed for healthy growth. Depending on the results,
amendments might include fertilizers, composted manure, peat moss, mulch, or
decompaction agents.
• Noxious or invasive weeds—Weeds can and often will outcompete and kill young trees.
Present and future generations of noxious or evasive weeds might reside at the site
(Figure 5-6). Weed seeds are very hardy and can lay dormant in the soil for years
waiting for favorable conditions to germinate. Controlling noxious and invasive weeds
should occur before tree planting
through a mowing or other
removal method. In some cases, it
is prudent to even delay planting
for a year to get more complete
control of weed populations.
When converting cropland to
riparian forest buffer, establishing
a cover crop is a convenient weed
control method.
Animal damage—A variety of
animals can damage tree
seedlings by rubbing or trampling
them or by feeding on leafs,
stems, bark, or roots. Managers
need to make plans to keep them
away from planted areas.
Figure 5-6. Ailanthus altissima, or Tree of Heaven
is a common invasive found in riparian forest
buffers.
Human damage—Riparian buffers are sometime damaged by well-meaning actions by
residents. Mowing, clearing, and other landscaping improvements can limit ecological
functions. Public education and creating an awareness of the buffer value and purpose
will help limit this problem.
5-20
Chapter 5. Riparian Area Management
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
3.4 Buffer Width and Connectivity
Two important dimensional characteristics of riparian buffers are
• Width—The lateral measure of buffer vegetation on either side of the stream.
• Connectivity—The measure of how continuous the buffer is both laterally and
longitudinally. Gaps or breaks in the buffer serve to lessen connectivity (Figure 5-7).
In general, ecological functions are enhanced when buffers are wide and connected rather than
narrow and full of gaps. For example, wider contiguous buffers create more space and a wider
diversity of soils and vegetation to filter out sediment, nutrients, and other pollutants from upland
sources before they reach the stream. Gaps in the buffer decrease buffer continuity and
increase the chance of upland runoff concentrating and shooting through the gap to the stream.
Gaps also discourage the movement of wildlife along the stream corridor. For those and other
reasons, buffer-restoration objectives typically include making the buffer as wide and as
connected as possible.
Width is a controversial aspect of buffer design and protection. There is much variation in buffer
width recommendations in state and federal guidelines and peer-reviewed literature. Because
factors that influence ideal buffer widths such as soil type and subsurface biochemistry, are site-
specific, the location of a forest buffer can be more important than buffer width (Speiran 2010).
Additionally, optimal widths are function dependent. In other words, the ideal buffer width at a
location will also vary depending on whether the highest priority in terms of buffer function is
water quality, stream temperature, or wildlife habitat. For example, DeWalle (2010) found that
increasing buffer widths beyond 12 meters has a limited effect on stream shade and that the
density and height of buffer vegetation near the stream are more important.
For further discussion on the scientific data related to width and pollutant removal, see Mayer et
al. 2005 and Okay 2007. Todd (2002) points out that a clearly defined relationship does not
exist between buffer efficiency and width that can be applied to the Chesapeake Bay region but
concludes that the potential risk for failure of a buffer to remove excess nutrients before they
reach the stream clearly increases with decreasing buffer width.
Chapter 5. Riparian Area Management 5-21
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
B
Source: FISRWG1998
Figure 5-7. Connectivity within a landscape.
In 1991 the U.S. Forest Service released specifications for riparian forest buffer design for
protecting and enhancing water resources (Welsch 1991). That document recommends that a
riparian buffer should follow a three-zone design, illustrated in Figure 5-8.
While buffers will vary in accordance with factors discussed above, generally, the first zone next
to the stream should be at least 15 feet wide and consist of mature tree cover, which protects
streambanks, reduces thermal impacts, and contributes organic matter to the stream.
Immediately adjacent to the first zone is the second zone, which typically should have a
minimum width of 60 feet and consists of trees and shrubs. The primary purpose of the second
zone is to capture and transform nutrients, sediments, and other pollutants from surface runoff
and shallow groundwater. Zone three should be approximately 25 feet wide and contain natural
grasses. That zone is an important area for the spreading, filtration, and infiltration of surface
water.
5-22
Chapter 5. Riparian Area Management
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
carefuty
managed
Concenlraled
(tows g can be
peimnted in
ZoneSijixMf
certain
condiitons
fASTURE
WWmng
lao lities and
irvestoch are
kaptouiofiha
RipaiianZon*
inwrfvu
practicable.
Source: Welsch 1991
Figure 5-8. A typical 3-zone buffer design.
Following those guidelines, the minimum buffer width should be 100 feet for maximum pollutant-
removal benefits, or wider where pollutant flows are greater or there is greater risk to
downstream waterbodies. That is consistent with riparian buffer ordinances in Virginia,
Pennsylvania, and Maryland (Baird and Wetmore 2003; MD CAC 2010; CWA PA 2009). Natural
Resources Conservation Service (NRCS) Conservation Practice Standards for Riparian Forest
Buffers in Maryland, Pennsylvania, and Virginia require a minimum 35-foot width of forested
area for cost sharing. However, a wider buffer is recommended in high nutrient, sediment, and
animal waste application areas, to include wetlands, steep slopes, and other critical elements,
or when buffers are planted for carbon storage (NRCS 2006, 2008, 2009). Additionally, in areas
where sediment is a major concern, a grassed filter strip (zone 3) at least 24 feet wide is
required.
More information about the benefits of the 3 zone design is in the USDA booklet titled Riparian
Forest Buffers: Function and Design for Protection and Enhancement of Water Resources at
http://www.na.fs.fed.us/spfo/pubs7n resource/riparianforests/ (Welsch 1991).
Chapter 5. Riparian Area Management
5-23
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
3.5 Establishing Riparian Vegetation
Choosing the species of trees to populate a riparian forest buffer requires matching growing
requirements with site conditions and planning objectives. In general, managers should strive to
create species patterns that mimic reference conditions in the area. Managers should also
consider the following when selecting plant species:
• Vegetation in the riparian forest buffer should be tolerant of different types of
meteorologic and hydrologic conditions.
• Choose plants that have multiple values, such as erosion control, nesting habitat, food
sources (nuts and fruit), and filtering capability.
• In areas of high erosion or where concentrated flow is an issue, trees, leaves, and
woody debris might be ineffective for the amount of sediment retention desired (Daniels
and Gilliam 1996; Knight et al. 2010). Consider adding a grass filter between the upland
and the riparian forest. Tall, dense, stiff grass species are preferred in such areas
(Dosskey2001).
3.5.1 Natural Regeneration
Natural regeneration is the least expensive option for establishing a riparian forest buffer.
Generally, natural regeneration will take longer to reach mature forest conditions, but it
eliminates the need (and costs) for selecting and planting trees. Key attributes for success are
the availability of native trees to function as a natural seed source and quality, non-compacted
soils that promote good seed contact. To achieve that latter attribute, some site preparation work
might be necessary.
Common tree species that generate windborne seeds that travel reasonably far distances
include poplar, ash, pine, sycamore, birch, sweetgum, and maple. Seeding by heavier seed
species (e.g., oaks and hickories) require trees that are fairly close by, preferably upslope.
Initial germination might yield thousands of seedlings per acre (Bradburn et al. 2010). Therefore,
thinning the buffer at some point might be appropriate to create a healthier population of trees.
More information is in chapter 3 of the Maryland DNR FS Riparian Forest Buffer Design and
Maintenance Guide
(http://www.dnr.state.md.us/forests/download/rfb design&maintenance.pdf).
5-24 Chapter 5. Riparian Area Management
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
3.5.2 Planting Trees
Planting results in more control of the location, density, and species on the site. It also speeds
up the restoration process. However, it can be considerably more expensive than natural
regeneration. Seeds, seedlings, or more mature trees can be planted on the site, depending the
budget and objects of the planting.
• Direct seeding—Seed can be directly sown in the soil and aided by raking or discing,
depending on the density of the seeds. Because of potential predation by squirrels,
birds, and other animals, a fairly large number seeds is required. If germination is
successful, dense stands can develop, which might need to be eventually thinned.
• Seedling planting—Seedlings can be planted by hand or using a planting machine.
Unlike direct seeding, managers can tightly control tree location, pattern, and density. In
addition to a good selection of seedling species available from nurseries, planting
seedlings is usually the most cost-effective method of establishing trees in a riparian
forest buffer. Care must be taken, however, to not damage or dry out seedlings during
the plant process. Managers generally choose to plant seedlings in rows because such a
configuration is easiest to design, install, and maintain. It also generates a full canopy
closure more rapidly than other configurations.
• Tree planting—In some cases, managers might want to plant more mature trees at the
site. Digging planting holes is more costly, but it avoids trampling high-traffic areas.
• Species choice—Choosing the species of trees to populate in the riparian forest buffer
requires matching growing requirements with site conditions and planning objectives. In
general, managers should strive to create species patterns that mimic reference
conditions in the area.
Forest conditions, and corresponding ecological functions, develop more quickly with a high
density of trees. If the rapid creation of a canopy for shading out weeds or providing cover and
shade to a stream is the objective, high-density planting is recommended (e.g., 500 trees per
acre). However, thinning back to 100 to 150 trees per acres will eventually be needed to create
a healthy, self-sustaining riparian forest buffer (MDNR FS 2005).
The Stroud Water Research Center recommends planting at least 8 to 10 species when
restoring a riparian area. In all cases, species must match the environmental characteristics of
the site, and plans should be defined to protect seedlings from weeds and animals.
Chapter 5. Riparian Area Management 5-25
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
Additional information, including suggestions for the species to plant in the Chesapeake Bay
area, is in the following resources:
• Pennsylvania Stream ReLeaf ToolKit
(http://www.dep.state.pa.us/dep/deputate/watermgt/wc/Subiects/StreamReleaf/Forestbuff
tool/default, htm)
• Chapter 3 of the Maryland DNR FS Riparian Forest Buffer Design and Maintenance
Guide (http://www.dnr.state.md.us/forests/download/rfb design&maintenance.pdf).
• Chesapeake Bay Alliance (http://www.alliancechesbay.org/proiect.cfm?vid=158)
• University of Maryland (http://www.riparianbuffers.umd.edu/fact/FS725.html)
• Virginia Department of Forestry
(http://www.dof.virginia.gov/mgt/rfb/rfb-common-plants.htm)
3.5.3 Protecting Seedlings
Young seedlings are susceptible to competition from weeds and animal damage. Protecting the
investment is an important part of riparian forest buffer management.
Many species of grasses and weeds can out-compete tree seedlings for light, water, nutrients,
and growing space. Fortunately, riparian forest buffer managers have several options to protect
the planting investment until they get a foothold.
• Hand clearing—Pulling and cutting weeds species by hand is an option for small riparian
areas. It is labor intensive, however. Some invasive species require the removal of entire
root systems.
• Mats, collars, and mulch—Physical barriers for weed growth can be very effective in
preventing weed competition around young trees. Some mats and tree collar products
can be treated with a selective herbicide for added protection. Mulch can also provide a
physical barrier to protect seedlings from weeds, but it too can be expensive and must
be replenished.
• Tree shelters—Tree shelters are designed to protect young trees from weeds and
wildlife. Sweeney et al. (2002) found that using shelters yields a survival rate four times
higher than seedlings without shelters. In addition, sheltered trees have 19 times better
vertical growth. Tubes that are ventilated, lighter in color, and designed to let in more
light tend to work best (Figure 5-9).
5-26 Chapter 5. Riparian Area Management
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
Figure 5-9. Trees protected with tubes.
In addition to weeds, several animal species can harm seedlings above and below the ground.
Manager can use several techniques to discourage or prevent their access to young trees.
• Fencing—Fencing can be used to limit access to the riparian forest buffer by livestock,
deer, and other larger animals (Figure 5-10). It can be electric or woven wire. To be
effective, deer fencing needs
to be well-designed and
around 8 feet tall. Gates
might need to be built in for
•
human access. Additional
information on livestock
exclusion fencing is in the
Agriculture chapter.
• Tree shelters—Shelters are a
physical barrier for browsing
deer. They also keep voles
from seedling roots provided
that the tube is pushed into
the soil a few inches. Figure 5-10. Fencing limits access to the stream.
Chapter 5. Riparian Area Management
5-27
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
3.5.4 Reinforcement Planting
Reinforcement plantings might be necessary if some portion of original seedlings die. Before
undertaking such an action, however, riparian managers should investigate why they did not
survive or how they were damaged and then adjust planting methods and follow-up care
accordingly. In some cases, a single factor might be the cause of tree mortality; in other
instances, a combination of factors might be in play.
3.6 Cost
Costing is, of course, a key part of the planning process. The Maryland Cooperative Extension
Service estimates that a typical forest buffer costs between $218-$729 per acre to plant and
maintain (Tjaden and Weber 1998). However, costs vary widely and depend on the size and
type of buffer. Managers must make choices at each step in the development process; from
site-preparation alternatives, to planting methods, to seedling protection approaches, and
follow-up maintenance. There is also a cost in taking the land out of crop production, if the
landowner or a renter is farming the land. The National Agroforestry Center developed an Excel-
based tool called Buffer$ (http://www.unl.edu/nac/buffer$.htm) to help landowners analyze cost
benefits of buffers compared to traditional crops.
The following resources are available for helping landowners determine the cost of establishing
a riparian buffer on property:
• Klapproth and Johnson. 2009. Understanding the Science Behind Riparian Forest
Buffers: Resources for Virginia Landowners.
• Maryland Cooperative Extension. Fact Sheet 774. When a Landowner Adopts a Riparian
Buffer—Benefits and Costs (http://www.riparianbuffers.umd.edu/PDFs/FS774.pdf).
• North Carolina State University, Cooperative Extension Service. 2003. Cost and Benefits
of Best Management Practices to Control Nitrogen in the Upper and Middle Coastal
Plain (http://www.neuse.ncsu.edu/Ag%20621.pdf).
• USDA NRCS. 1997. 1997 Conservation Reserve Program practice cost and flat rate
payment estimates for Virginia, March 1997.
5-28 Chapter 5. Riparian Area Management
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
4 Protection and Maintenance of Riparian Areas
Implementation Measure R-2:
Protect from adverse effects riparian areas that are serving a significant nonpoint
source-abatement function and maintain that function while protecting the other
existing functions of the riparian areas.
4.1 Background
The current rate of loss of riparian forests
in the Chesapeake Bay is unknown. The
long-term goal of having riparian forests
on 70 percent of all streambanks and
shorelines in the Chesapeake Bay
requires not only the restoration of buffers,
but also strong protections for existing
buffers to maintain that goal. Existing
riparian buffers and restored riparian
buffers (Figure 5-11) that have been
established for several years must be
protected and maintained to keep them
functioning as desired.
Figure 5-11. A healthy riparian buffer.
The previous section discusses
restoring and reestablishing
riparian forest buffers. This
section provides information on
recommended long-term
maintenance activities and
methods jurisdictions can use to
protect existing riparian buffers.
An example of a riparian area evaluation on the watershed scale
is that of Johnson County, Indiana (Letsinger 2004). In that
study, the author assessed the current status of buffers (width
and type) in the watershed. She digitally mapped existing buffers
on an aerial photograph base and used multiple field surveys to
ground truth the remote-sensing methods. Next she used a
simplified numerical model to simulate hydraulic routing. She
used the model to identify all riparian areas, impaired areas, and
areas with the potential for flooding or increased erosion. That is
useful in determining which areas should be the focus protection
and maintenance efforts.
Chapter 5. Riparian Area Management
5-29
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
4.2 Long-Term Maintenance
Existing riparian buffers, including those that have been restored, require long-term maintenance
to maintain their desired functions, especially in terms of filtering P, N, and sediments from
upland areas and preventing those pollutants from entering the Chesapeake Bay.
4.2.1 Watershed-Scale Evaluation
The first step in determining long-term maintenance of riparian buffers on a broad scale (at the
state or county level) is to determine the extent of riparian buffers in the watershed.
RIPARIAN FOREST COVER BY SUB-WATERSHED
Buffer boundaries can be mapped and, with proper legal authority, specific rules can be applied
to protect and manage the buffer. Some maps already exist that show riparian buffer areas in
the Chesapeake Bay. For example, Pennsylvania State University mapped the extent and
change in riparian forest buffers for the entire Chesapeake Bay watershed (Day and Crew 2005)
using the 1992 National Land Cover Dataset and the University of Maryland's MA-RESAC 2001
data set (Claggett et al. 2010). The
extent of riparian buffers in any
watershed can be determined using
tools such as geographic information
systems, remote sensing, and
hydrologic modeling. Satellite images
and high-resolution aerial photography
can help in the evaluation of each
riparian area. For example, The
Connecticut's Changing Landscape
project, at the University of
Connecticut's Center for Land Use
Education and Research used basic
GIS analysis tools and remotely
sensed land use data to evaluate land
cover change within riparian corridors
between 1986 and 2006.
(http://clear.uconn.edu/projects/riparia
n buffer2/index.htm).
^» >70%
^B 60S 70%
C ) 40%-60%
20% • 40%
^B <20%
Z7/7// Watersheds with <70% buffers
and .-('ill niliogen lemoval potential
The Riparian Buffer Mapper
(RBMapper) software developed by
GDA Corp with support from the
Chesapeake Bay Program,
Source: Chesapeake Bay Program 2005.
Figure 5-12. A forest cover map.
5-30
Chapter 5. Riparian Area Management
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
U.S. Geological Survey (USGS), and USDA FS is a tool that might be helpful for buffer
delineation. The program outputs a land cover map of riparian buffers (Figure 5-12) and a text
report with land cover statistics.
On-site methods might also be needed, such as performing various types of field surveys that
look at geomorphology, hydrology, habitat, wildlife, soils, plant inventories, and so forth. A good
approach would be to use a combination of remote and on-site methods to evaluate the
streambanks in the watershed in terms of channel geometry, land use, soil types, and
vegetation. The targeting matrix proposed by the Chesapeake Bay Program Forestry
Workgroup and described in Section 3.3 might also be useful in helping to identify areas where
riparian buffers are most likely to exist.
Some sources of maps, satellite imagery, and land cover data in the Chesapeake Bay
watershed include the following:
• RBMapper (http://gdacorp.web5.hubspot.com/rb-mapper/)
• Chesapeake Bay Program (www.chesapeakebay.net/maps.aspx?menuitem=16825)
• USGS (http://www.usgs.gov/pubprod/)
• Mid-Atlantic Regional Earth Science Applications Center (MA-RESAC)
(www.geog.umd.edu/resac/)
It is also important to evaluate the size (length, width) of each existing riparian buffer area to
determine whether it is adequate to protect the Chesapeake Bay from nonpoint source pollution,
or serve other functions such as providing wildlife habitat, stabilizing streambanks, or protecting
the fish population. Typically, longer and wider buffers are better at filtering and removing
pollutants and provide better wildlife and aquatic habitat, as described earlier in this document.
4.2.2 Evaluation of Buffer Quality
Once the buffers are located in the watershed, it is important to determine whether they are
achieving the desired functionality. Riparian buffers that are functioning well should be
maintained and protected, while those buffers not functioning well might need more significant
restoration (see Section 3 of this chapter). Specifically, land managers should evaluate the
following:
• Hydrologic Condition
• Adjacent Land Use
• Wildlife Habitat
Chapter 5. Riparian Area Management 5-31
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
Hydrologic Condition
Managers must understand existing and future As described in earlier sections, one of j
hydrogeomorphic conditions and consider them the most important functions of a riparian j
when developing management plans to ensure that buffer is to protect water quality by j
riparian buffers maintain their functions. Hydrologic filtering nonpoint source pollution coming j
and geomorphic conditions help maintain many of from adjacent land. While that is an i
the functional aspects of a riparian area, such as important function, riparian buffer ||
pollutant removal, habitat maintenance, and water managers should not alter riparian areas j
storage and transport. It is important to understand to improve their water qua|ity function at j
the natural flow patterns (frequency, magnitude, the expense of other functjons |
duration) associated with each riparian buffer, , jj
especially where flow regimes have been modified
(NRC 2002). Channel incision and widening from certain land use practices can curtail overbank
flows. Information on historical conditions from overbank flood events is useful to know whether
healthy riparian communities are possible and whether incision and widening is reversible
(NRC 2002).
Climate change creates uncertainty in managing riparian areas in the Chesapeake Bay. In the
upcoming years, plant species might experience a change in their growth rates and be exposed
to higher average temperatures and changes in typical rainfall (Sprague et al. 2006). In light of
this, hydrologic regimes are likely to change. Streams might experience more frequent effects of
severe floods, droughts, and hurricanes. To prepare for that, managers should assess how the
stream channel will function ecologically under extreme low-flow or high-flow conditions and
inspect the condition of a riparian buffer after a significant metrological or hydrological event
occurs to determine if any maintenance is needed.
Adjacent Land Use
Land use directly affects the characteristics of runoff through a riparian buffer. The pollutant-
removal effectiveness of the buffer will depend on the conditions of the upland land cover where
the runoff originates (i.e., urban, suburban, pervious, impervious, agricultural, tilled, no till) (NRC
2002). Therefore, addressing practices in the upland land uses that contribute to riparian
degradation is an important component of a successful riparian restoration project.
Agriculture runoff (high in nutrients, bacteria, and TSS) will be different from urban runoff (high
in nutrients, heavy metals, pesticides, hydrocarbons, temperature, oxygen-demanding
substances, and trash and debris) (USEPA 1996). Forested land has unique factors that
managers should consider in terms of maintaining and protecting existing riparian areas. For
example, timber harvesting must be managed so it does not increase water and sediment yields
5-32 Chapter 5. Riparian Area Management
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
and lead to stream channel destabilization and loss of aquatic habitat. The forest landowner
should also not decrease woody, in-stream cover. Doing so could destabilize streambanks,
reduce shading, increase water temperatures, reduce inputs of fine litter to the waterbody, and
reduce the diversity of plants and animals in the area. From a landscape perspective, managing
a greater proportion of the riparian area for uneven-aged, mixed stands of longer-lived species
suitable to the site can help protect riparian functions and values. The agriculture, forestry, and
urban chapters of this document provide detailed information on managing different land uses to
prevent and reduce nonpoint source pollution from entering the Chesapeake Bay.
Habitat
Managers should evaluate habitat to determine whether it is adequate to support the desired
plant and animal species. Examples of both terrestrial and aquatic habitat assessments include
the following:
• Maryland DNR (http://www.dnr.md.gov/streams/pubs/ea03-4phi.pdf)
• Ohio Environmental Protection Agency
(http://epa.ohio.gov/portals/35/wqs/headwaters/PHWHManual 2009.pdf)
• The Nature Conservancy Active River Area
(http://www.nature.org/initiatives/freshwater/files/active river area.pdf)
Additional Information
The following sources have additional information on the proper assessment of riparian buffers:
• Riparian Area Management—Process for Assessing Proper Functioning Condition
(USDI 1998)
• Methods for Evaluating Riparian Habitats with Applications to Management
(USDA FS 1987)
• Riparian Assessment Using the NRCS Riparian Assessment Method (NRCS 2004)
• Development of Methodologies to Evaluate the Health of Riparian and Wetland Areas
(Hansenetal. 2000)
4.2.3 Managing Plants
In addition to the factors discussed in the previous section, the plant species in riparian buffers
need to be maintained so that the areas retain their desired functions. Some studies have found
that pollutant-removal functions can increase over time (Rheinhardt et al. 2009). Consider the
planting, harvesting, pruning, and nurturing protocols required to protect the riparian species
Chapter 5. Riparian Area Management 5-33
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
from degradation. Managers might need to deal with new plants, invasive species control,
wildlife damage issues, and disease issues. A landowner can contact the local NRCS office or a
nursery for assistance.
Plantings
To manage existing areas so that they are effective long into the future, managers should
determine the variations in riparian communities in a watershed and whether they are
appropriate on the basis of factors such as soil type, hydrology, and land use. The species that
exist in the riparian buffer need to be examined to determine whether they are appropriate for
the desired effects of the buffer (such as wildlife and aquatic habitat) and whether they are
suitable for the site conditions. Native vegetation is typically better capable of withstanding local
water, climate, soil, and pest conditions.
Riparian buffer managers should consider the following:
• Climate change could bring about changes in temperature and rainfall amounts that
could affect vegetation's growth and survivability and could increase the types or amount
of invasive species.
• Keep an eye on riparian areas for plant die-off. First, determine the cause of the issue
(for example, is the die-off due to wildlife damage, or are the site conditions
inappropriate for the plants that are struggling?). Next, act quickly to repair any damage
or replant additional vegetation.
• Some riparian sites warrant botanical generalists, whereas other might warrant wetland
specialists. It depends on the site conditions. Remove certain species that are not
appropriate to the site conditions or plant new vegetation.
Weed Control
Riparian buffers should be managed over the long-term to ensure that native vegetation is being
established/maintained along the waterways. As mentioned in Section 3, weeds and invasive
species can overtake a riparian area, causing damage to other species by competing for
resources. Techniques to remove weeds, such as mowing, and hand clearing, are important to
consider using for long-term maintenance of a riparian buffer. For details on those techniques,
see Section 3.
Some good resources for identifying weeds and invasive species in the Chesapeake Bay are
• USDA NRCS (http://plants.usda.gov/iava/noxiousDriver)
• Native plant societies
5-34 Chapter 5. Riparian Area Management
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
• Virginia (www.vnps.org/)
• Maryland (www.mdflora.org/)
• District of Columbia (www.botsoc.org/)
• Pennsylvania (www.pawildflower.org/)
Preventative management, however, is the best method of weed control. This includes things
like not disposing of plant clippings in riparian areas, not planting invasive species nearby, and
removing problem plants as soon as they are spotted.
Note: When considering weed removal, when mechanized clearing is employed in an aquatic
area, a permit may be required from the U.S. Army Corps of Engineers pursuant to Clean Water
Act section 404.
Pruning, Harvesting, and Nurturing
In an existing riparian forest buffer, riparian buffer managers should check the conditions of any
plants in the buffer periodically, especially after significant storm events, and consider planting
additional species if needed to maintain the buffer's integrity. Check the area for damaged,
diseased, or dying trees and shrubs that might need to be pruned or removed and replaced
(contact NRCS, a cooperative extension, or local nursery for assistance). Check for fallen or
leaning trees and whether they present a hazard to upland land uses. Although fallen trees can
provide valuable habitat, trees threatening to cause significant damage might need to be pruned
or removed.
Check during drought conditions, and water plants if necessary. Some trees might need to be
harvested to remove nutrients and chemicals stored in their stems (Schultz et al. 1997) and to
allow stronger trees to grow. However, managers must take care not to overharvest because
that could be disruptive to the existing plant and animal communities and could lead to
increased streambank erosion (USEPA 2005).
Below are sources of additional information on pruning, harvesting, and nurturing protocols.
• US DA FSA (http://plants.usda.gov/iava/noxiousDriver)
• Maryland DNR Forest Service (http://www.dnr.state.md.us/Forests/)
• Virginia Forest Service (http://www.vaforestservice.com/Forest Management.aspx)
• Pennsylvania DNR (http://www.dcnr.state.pa.us/trees.html)
• Weeds Gone Wild (http://www.nps.gov/plants/alien/)
Chapter 5. Riparian Area Management 5-35
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
If the riparian forest buffer is part of an ongoing forestry operation, some limited harvest in
accordance with BMPs for water quality (and associated guidelines for streamside management
zones) may be allowed in the buffer, but workers should minimize land disturbance. Burning and
pesticide and fertilizer use might also be restricted. For more information, see Chapter 4 of this
document.
Agricultural land that has forested riparian buffers should be addressed using these same
principles for selective harvest and could be subsequently reforested or used for other
agricultural pursuits. For more information, see Chapter 2 of this document.
Fencing
Fencing, in some cases, can be an effective means of protecting riparian vegetation. Fences
can be used to keep out or control livestock movement and grazing and to direct human
activities into other areas. Fences serve to delineate land uses and prevent human activity from
encroaching on the riparian zone. Many different fencing options exist, and it is important to
identify the specific management requirements so that the location and design of fencing and
gates, is appropriate and effective. Fencing needs to be inspected regularly for damage caused
by weather, wildlife, or vandalism, and repaired if needed. Additional information on livestock
exclusion fencing is in Chapter 2 of this document.
Erosion and Sediment Control
Riparian buffers should be inspected annually and after significant rainfall events for signs of
erosion. Bare areas should be replanted, and additional soil might need to be added. In
addition, over time or after a significant rainfall event, sediment that is trapped in the riparian
area can build up and bury groundcover. Sediment can also build up at the edge of a buffer and
block water flow. In those cases, the sediment should be removed, and some vegetation might
need to be replanted. If it becomes an ongoing problem, the adjacent area might need better
management practices installed.
4.3 Protection
Federal, state, nonprofit, and private programs, both regulatory and nonregulatory, exist to
protect riparian functions. Creating ordinances and zoning to protect existing riparian areas is
likely to be less expensive than establishing new areas or restoring degraded ones (Mayer et al.
2005). It has been recommended by a federal interagency report that states should, "Limit or
eliminate development within riparian areas, using a similar approach such as Maryland's
Critical Areas legislation and Virginia's Chesapeake Bay Preservation Act" and "create
incentives to ensure that restored buffers remain intact" (Greiner and Vogt 2009).
5-36 Chapter 5. Riparian Area Management
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
4.3.1 Acquisition
The vast majority of land within the Chesapeake Bay watershed is held by private landowners.
However, a government agency, nonprofit organization, or private citizen can purchase land
where riparian areas exist as a means of protecting them from future degradation. Millions of
acres of habitat in the 64,000-square-mile Chesapeake Bay watershed are already protected by
federal, state, and local government programs and private organizations such as The Nature
Conservancy, The Natural Lands Trust, and other land trusts (Greiner and Vogt 2009).
Fee Simple Acquisition
A local government or conservation group can do a fee simple acquisition, which gives it the full
ownership of riparian land and provides the greatest amount of control over the use and
maintenance of a property. This type of ownership is most desirable if the resources on the land
are highly sensitive, and protection of the resources cannot be reasonably guaranteed using
other approaches for conservation.
Conservation Easement
An alternative to buying riparian land is to purchase the property owner's right to use that
riparian land for specific purposes by purchasing a conservation easement. A conservation
easement is a written legal agreement between a landowner and a land trust or a local
government that permanently restricts some landowner rights to the use of a property to protect
its conservation value.
Some easement transactions offer tax benefits. A landowner who donates an easement or sells
it for less than fair market value (for example, to a land trust) could be entitled to a federal
income tax deduction. Such land must be used exclusively for conservation purposes. The
easement is legally transferred but at no cost or at below-market value to the easement holder.
That allows the landowner to qualify for a tax-deductible charitable donation.
4.3.2 Zoning and Protective Ordinances
Local governments often administer the regulations or incentives necessary to encourage
private landowners to protect riparian areas. Land use ordinances are commonly used for that
purpose. Land use ordinances define land use restrictions and plans. Zoning is one of the most
common types of land use ordinances. Zoning that protects riparian buffers might be part of an
existing natural resource protection ordinance, stormwater ordinance orfloodplain ordinance in
a state. Managers should review such regulations for their adequacy in protecting riparian
areas. An overlay zoning ordinance pertaining to riparian buffer protection is appropriate in a
municipality that already has a zoning ordinance in place. For a municipality that does not have
Chapter 5. Riparian Area Management 5-37
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
zoning ordinances in place, a separate, freestanding ordinance might be necessary to protect
riparian buffers.
A stream buffer ordinance can be used to establish minimal acceptable requirements for buffer
design to protect streams and waterbodies in and around the Chesapeake Bay, and to provide
for the environmentally sound
use of the jurisdiction's land
resources. To see examples of
ordinances that can be used to
protect natural resources, see
www. stormwatercenter. net.
An example of a nonprofit agency that obtained a conservation
easement in the Chesapeake Bay is the Conservation Fund
(http://www.conservationfund.org/chesapeake bay initiative). The
Conservation Fund launched an ambitious program that seeks to
The stream buffer ordinance is
an example of a model
ordinance that can be used to
guide future growth while
safeguarding local natural
resources. By examining the
example provided, community
decision makers should find
the language to craft an
ordinance that is appropriate
for their conditions. A strong
buffer ordinance is one step in
preserving stream buffers.
protect 100,000 acres of high-priority land and water within the
watershed by 2010. Three miles of historic Chester River shoreline,
600 acres of unique Delmarva Bays, a 90-acre waterfowl
sanctuary, and important habitat for bald eagle and endangered fox
squirrel are now preserved forever under the 5,200-acre Chino
Farms conservation easement—the largest in Maryland's history.
The fund, collaborating with the landowner, Maryland DNR, Queen
Anne County, and U.S. Fish and Wildlife Service, ensured the
protection of more than 8 square miles of critical riparian habitat
and wetlands. This easement keeps Chino Farms in agricultural
production while conserving valuable natural resources in the
Chesapeake Bay watershed.
Another example of a riparian buffer ordinance is the Riparian Buffer Conservation Zone Model
Ordinance, which was prepared in 2005 by the Passaic River Coalition and New Jersey
Department of Environmental Protection, Division of Watershed Management:
http://www.marsh-friends.org/marsh/pdf/ordinance/StreamBufferOrdinance.pdf.
In some cases, through the municipal planning code, municipalities can take a regulatory or
incentive-based approach to protect riparian areas in new developments. The degree of riparian
area protection is likely to vary with the approach. Best results occur when a municipality
identifies riparian areas to protect early in the planning stage of a new development.
Communication during early planning stages, before commitments and decisions have been
made, often promotes goodwill efforts from the developer. Amenities such as greenways or
trails along stream corridors that result from municipal intervention can benefit the developer
and protect the water resource because such green spaces can enhance the desirability of
property in a new development.
5-38
Chapter 5. Riparian Area Management
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
In some jurisdictions,
developers can be awarded
increased building densities for
developments that conserve
natural areas, such as riparian
corridors. Conversely,
municipalities can employ
density limits to encourage
conservation of natural areas.
For example, a jurisdiction
could establish a minimum and
maximum density and permit
the higher density to a
developer that plans for natural
areas and open space
techniques while lowering the
allowable density for
developments that do not
incorporate preservation of
natural areas.
Created in 1999, this program strives to manage toward, protect,
and restore natural geomorphic conditions in streams. A big part of
this program is river corridor protection. The two protection
mechanisms are state and municipal land use restrictions on
development in fluvial erosion hazard area and the purchase of
river corridor conservation easements. The state used Stream
Geomorphic and Reach Habitat Assessment protocols to delineate
river corridors throughout the state and used this information to
develop FEH areas. River corridor easements were created to
augment the FEH land use ordinances. The purpose of the
easement is to give the river the space to re-establish a natural
slope, meander pattern, and floodplain connection (Kline and
Cahoon 2010). More information on this program can be found at
http://www.anr.state.vt.us/dec/waterq/rivers/htm/rv restoration.htm
The Stormwater Center (http://www.stormwatercenter.net/ModelOrdinances/buffer model ordinance.htm)
includes a template and sample ordinances, including one from Baltimore County, Maryland. Some of the
major sections of a stream buffer ordinance are
• The intent of the ordinance
• Examples of what type of land buffers are applied to (i.e., forest, agriculture)
• Plan requirements (i.e., maps, surveyed streams and forest buffers, limits of a 100-year floodplain,
mapped hydric soils, slopes measures, summary of species of vegetation)
• Design standards for forest buffer (i.e., width, slope)
• Management and maintenance of buffers (i.e., limitations on alteration of natural conditions,
maintenance of roads, bridges, paths, utilities, stormwater management)
• Enforcement procedures (i.e., checking for violations, civil or criminal penalties)
• Waivers/Variance (i.e., ordinance applies to all development after effective date)
• Conflict with other regulations (i.e., more restrictive regulation will apply)
Chapter 5. Riparian Area Management
5-39
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
In some states, like Pennsylvania, a riparian buffer can be used as a stormwater credit, which is
a technique that developers can use to reduce their stormwater management costs (Alliance for
the Chesapeake Bay 2004). A stormwater credit for a stream buffer would be given when runoff
from upland areas is treated by a grass or wooded buffer. Such techniques reduce runoff
volumes, which helps to avoid the construction of costly stormwater management facilities.
4.3.3 Water Quality Standards
A state can use its water quality standards to protect existing riparian areas. For example, North
Carolina has the Sediment Pollution Control Act, under which it declares that for forestry
operations, a streamside management zone (SMZ) (i.e., buffer) must be established and
maintained along the margins of intermittent and perennial streams and perennial waterbodies.
The SMZ must be of sufficient width to confine within the SMZ visible sediment resulting from
accelerated erosion (NCDENR 1999).
In Maryland's water quality standards, it is the policy that riparian forest buffers adjacent to
certain waters must be retained when possible to maintain water temperature to protect
salmonid fish. Maryland and Virginia have water quality standards that allow certain waters to
be listed as exceptional state waters, which receive certain protections from antidegradation.
(MDE 2009; VDEQ 2009).
4.3.4 Regulation and Enforcement
Individual local governments create and adopt development regulations to help retain riparian
forest buffers in urbanizing areas. In Virginia, many local buffer ordinances (Section 4.3.2) were
developed as part of implementing the Chesapeake Bay Act (VDCR 2010).An evaluation of the
Maryland Critical Area Program found a much higher rate of loss of resource lands outside the
designated critical areas after the program's enactment (Hillyer2003). Maryland also has the
Forest Conservation Act, which requires conservation of forests and mitigation of forest loss
within a hierarchy that recommends that riparian forests be the highest priority for protection
(MDNRFS 1991).
5-40 Chapter 5. Riparian Area Management
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
4.3.5 Education and Training
Activities that encroach on buffers
are often not done purposefully
but out of a lack of awareness.
Education and outreach are
important tools for promoting an
understanding of the importance
of riparian areas in maintaining
water quality and protecting
habitat and other valuable
functions that they perform
(USEPA 2005). Communities
should work to make buffers more
visible to the public and publicize
the buffer's purpose and value to
adjacent property owners. That
can be accomplished in many
ways, as recommended by EPA
and the Center for Watershed
Protection, including
• Marking buffer boundaries with permanent signs that describe allowable uses
(see Figure 5-13)
• Educating property owners about buffer
benefits and uses via newsletters, pamphlets,
meetings, and such and encourage a
stewardship ethic
• Teaching courses in restoration techniques for
landowners
Baltimore County Public Schools have an annual Forest Buffer
Restoration Project and Forest Buffer Maintenance Project
where every high school in Baltimore is invited to participate. In
the spring of 2008, almost 900 high school students from 18
Baltimore County Schools took part in the restoration effort and
planted over 700 native trees and shrubs in conjunction with
the Chesapeake Bay Trust, Baltimore County Forestry Board,
and Baltimore County Department of Recreation and Parks
and either take place on school land or at another designated
location. During the Forest Buffer Maintenance Project
students will map the planting areas to show where the trees
and shrubs were planted, complete a survival/mortality count,
and perform maintenance on the plantings such as pruning and
staking. These activities are taught in the Forestry Unit of the
High School Environmental Science Curriculum.
• Ensuring that when property is sold, the new
owners receive information about allowable
uses and limits of the buffer
• Conducting annual buffer walks to assess
buffer health and check for encroachment
Figure 5-13. Sign fora 1.2-acre riparian
forest buffer restoration in Virginia.
Chapter 5. Riparian Area Management
5-41
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
5 References
Alliance for the Chesapeake Bay. 2004. Riparian Forest Buffers. Public Policy Program White
paper, July 2004. Alliance for the Chesapeake Bay, Annapolis, MD.
Angier, J.T., and G.W. McCarty. 2008. Variations in base-flow nitrate flux in a first-order stream
and riparian zone. JAWRA. 44(2):367-380.
Baird A., and D. Wetmore. 2003. Riparian Buffers Modification and Mitigation Guidance Manual.
Virginia Department of Conservation and Recreation.
Bradburn, B.N., W.M. Aust, C.A. Dolloff, D. Cumbia, and J. Creighton. 2010. Evaluation of
riparian forests established by the Conservation Reserve Enhancement Program (CREP)
in VA. Journal of Soil & Water Conservation 65(2): 105-112.
Chesapeake Bay Program. 2005. Maps—Bay Watershed.
. Accessed February
2010.
Chesapeake Executive Council. 2003. Directive No. 03-01 Expanded Riparian Forest Buffer
Goals. Chesapeake Bay Program, Annapolis, MD.
Claggett, P.R., J.A. Okay, and S.V. Stehman. 2010. Monitoring regional riparian forest cover
change using stratified sampling and multiresolution imagery. JAWRA 46(2):334-343.
CWA PA (Clean Water Action Pennsylvania). 2009. Buffers 100: Taking a Positive Trend
Statewide. Clean Water Action Pennsylvania, Philadelphia, PA.
Craig, L.S., M.A. Palmer, D.C. Richardson, S. Filoso, E.S. Bernhardt, B.P. Bledsoe, M.W.
Doyle, P.M. Groffman, B.A. Hassett, S.S. Kaushal, P.M. Mayer, S.M. Smith, and P.R.
Wilcock. 2008. Stream restoration strategies for reducing river nitrogen loads. Frontiers in
Ecology and the Environment 6(10):529-538.
Daniels, R.B., and J.W. Gilliam. 1996. Sediment and chemical load reduction by grass and
riparian filters. So/7 Science Society of America Journal 60:246-251.
Day, R.L., and R.C. Crew. 2005. Chesapeake Bay Riparian Forest and Wetland Buffer
Inventory: Final Report. Pennsylvania State University, Land Analysis Laboratory.
DeWalle, D.R. 2010. Modeling stream shade: Riparian buffer height and density as important as
buffer width. JAWRA. 46(2):323-333.
Dosskey, M.G. 2001. Toward quantifying water pollution abatement in response to installing
buffer on crop land. Environmental Management 28(5):577-698.
5-42 Chapter 5. Riparian Area Management
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
Dosskey, M.G., D.E. Eisenhauer, and M.J. Helmers. 2005. Establishing conservation buffers
using precision information. J Soil Water Conse/v60(6):349-354.
Dosskey, M.G., P. Vidon, N.P. Gurwick, C.J. Allan, T.P. Duval, and R. Lowrance. 2010. The role
of riparian vegetation in protecting and improving chemical water quality in streams.
JAWRA 46(2):261-277.
FISRWG (Federal Interagency Stream Restoration Working Group). 1998. Stream Corridor
Restoration: Principles, Processes, and Practices. GPO Item No. 0120-A; SuDocs No. A
57.6/2:EN 3/PT.653. ISBN-0-934213-59-3. Federal Interagency Stream Restoration
Working Group.
Greiner, J., and B. Vogt. 2009. Habitat and Research Activities to Protect and Restore
Chesapeake Bay Living Resources and Water Quality (202g) Report. National Oceanic and
Atmospheric Administration Chesapeake Bay Office, and U.S. Fish and Wldlife Service.
Harmon, M.E., J.F. Franklin, F.W. Swanson, P. Sollins, S.V. Gregory, J.D. Lattin, N.H.
Anderson, S.P. Cline, N.G. Aumen, J.R. Sedell, G.W. Lienkaemper, K. Cromack, Jr., and
K.W. Cummins. 1986. Ecology of coarse woody debris in temperate ecosystems.
/Advances in Ecological Research 15:133-302.
Hillyer, S.C. 2003. An Evaluation of the Maryland Critical Area Program Effects on Conservation
of Resource Lands and Patterns of Development. The Abell Foundation, Baltimore, MD.
Klapproth, J.C., and J.E. Johnson. 2009. Understanding the Science Behind Riparian Forest
Buffers: Benefits to Communities and Landowners. Virginia Cooperative Extension,
Blacksburg, VA.
Knight, K.W., R.C. Schultz, C.M. Mabry, and T.M. Isenhart. 2010. Ability of remnant riparian
forests, with and without grass filters, to buffer concentrated surface runoff. JAWRA
46(2):311-322.
Leopold, L.B., M.G. Wolman, and J.P. Miller 1964. Fluvial Processes in Geomorphology. W.H.
Freeman and Company, San Francisco, CA.
Mayer, P., S.K. Reynolds Jr., and T.J. Canfield. 2005. Riparian Buffer Width, Vegetative Cover,
and Nitrogen Removal Effectiveness: A Review of Current Science and Regulations.
EPA/600/R-05/118. U.S. Environmental Protection Agency, Washington, DC.
MD CAC (Maryland Critical Area Commission for the Chesapeake and Atlantic Coastal Bay).
2010. Preserving Our Precious Natural Resources.
. Accessed February 2010.
Chapter 5. Riparian Area Management 5-43
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
MDNR FS (Maryland Department of Natural Resources Forest Service). 1991. The Maryland
Forest Conservation Act. Natural Resources Article, Section 5-1601 through 5-1613.
Maryland Department of Natural Resources, Forest Service, Annapolis, MD.
MDNR FS (Maryland Department of Natural Resources Forest Service). 2005. Riparian Forest
Buffer Design and Maintenance. Maryland Department of Natural Resources, Forest
Service, Annapolis, MD.
MDE (Maryland Department of the Environment). 2009. Maryland Water Quality Standards.
Code of Maryland Regulations (COMAR) 26.08.02. Maryland Department of the
Environment, Baltimore, MD.
McGlynn, B.L., and J. Seibert. 2003. Distributed assessment of contributing area and riparian
buffering along stream networks. Water Resour Res. 39(4): 1082
McKergow, LA., D.M. Weaver, IP. Prosser, R.B. Grayson, and A.E.G. Reed. 2003. Before and
after riparian management: Sediment and nutrient exports from a small agricultural
catchment. Western Australia. Journal of Hydrology 270:253-272.
NRC (National Research Council). 2002. Riparian Areas: Functions and Strategies for
Management. National Academy Press, Washington, DC.
NRCS (Natural Resources Conservation Service). 1997. 1997 Conservation Reserve Program
practice cost and flat rate payment estimates for Virginia, March 1997. U.S. Department of
Agriculture, Natural Resources Conservation Service, Virginia State Office. Richmond, VA
NRCS (Natural Resources Conservation Service). 2004. Riparian Assessment Using the NRCS
Riparian Assessment Method. U.S. Department of Agriculture, Natural Resources
Conservation Service Bozeman, MT.
NRCS (Natural Resources Conservation Service). 2006. Maryland Conservation Practice
Standard Riparian Forest Buffer, Code 391. U.S. Department of Agriculture, Natural
Resources Conservation Service, Washington, DC.
NRCS (Natural Resources Conservation Service). 2008. Pennsylvania Conservation Practice
Standard Riparian Forest Buffer, Code 391. U.S. Department of Agriculture, Natural
Resources Conservation Service, Washington, DC.
NRCS (Natural Resources Conservation Service). 2009. Virginia Conservation Practice
Standard Riparian Forest Buffer, Code 391. U.S. Department of Agriculture, Natural
Resources Conservation Service, Washington, DC.
5-44 Chapter 5. Riparian Area Management
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
NCDENR (North Carolina Department of Environment and Natural Resources). 1999.
Sedimentation Pollution Control Act of 1973 (SPCA), as amended through 1999. North
Carolina General Statutes Chapter 113A Article 4. North Carolina Division of Land
Resources, Raleigh, NC.
Netusil, N. 2006. Economic Valuation of riparian corridors and upland wildlife habitat in an urban
watershed. Journal of Contemporary Water Research & Education 134:39-45.
O'Driscoll, M.A., and D.R. DeWalle. 2010. Seeps regulate stream nitrogen concentration in a
forested Appalachian catchment. J. Environ. Qual. 39:420-431.
Okay, J.A. 2007. Appropriate Riparian Forest Buffer Widths and Functions for Chesapeake Bay
Program Tracking, jokay@chesapeakebay.net. Forestry Work Group (FWG) Document
41307.
Palone, R.S., and A.M. Todd, eds. 1997. Chesapeake Bay Riparian Handbook: A Guide for
Establishing and Maintaining Riparian Forest Buffers. NA-TP-02-97. U.S. Department of
Agriculture, Forest Service, Radnor, PA.
Patterson, R.W., and K.J. Boyle. 2005. Cosfe & Benefits of Riparian Forest Management: A
Literature Review. Minnesota Forest Resources Council, St. Paul, MN.
Polyakov, V., A. Fares, and M.H. Ryder. 2005. Precision riparian buffers for the control of
nonpoint source pollutant loading into surface water: A review. Environ Rev 13:129-144
Qiu, Z., T. Prato, and G. Boehm. 2006. Economic valuation of riparian buffer and open space in
a suburban watershed. Journal of the American Water Resources Association (JAWRA)
42(6): 1583-1596.
Rheinhardt, R.D., M. McKenney-Easterling, M.M. Brinson, J. Masina-Rubbo, R.P. Brooks, D.F.
Whigham, D. O'Brien, J.T. Hite, and B.K. Armstrong. 2009. Canopy composition and
forest structure provide restoration targets for low-order riparian ecosystems. Restoration
Ecology 17:51-59.
Schueler, T. 1995. Site Planning for Urban Stream Protection. Center for Watershed Protection.
Silver Spring, MD.
Schultz, R.C., P.M. Wray, J.P. Colletti, T.M. Isenhart, C.A. Rodrigues, and A. Kuehl. 1997.
Stewards of our Streams: Buffer Strip Design, Establishment, and Maintenance. Iowa
State University, Department of Forestry, Ames, IA.
Simpson, T.W., and S.E. Weammert. 2009. Riparian Forest Buffer Practice (Agriculture) and
Riparian Grass Buffer Practice: Definition and Nutrient and Sediment Reduction
Efficiencies for use in Calibration of the Phase 5.0 of the Chesapeake Bay Program
Watershed Model. University of Maryland, Mid-Atlantic Water Program, College Park, MD.
Chapter 5. Riparian Area Management 5-45
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
Schumm, S.A. 1977. The Fuvial System. John Wiley and Sons, New York, NY.
Speiran, G.K., P.A. Hamilton, and M.D. Woodside. 1998, Natural Processes for Managing
Nitrate in Ground water Discharged to Chesapeake Bay and Other Surface Waters—More
than Forested Buffers. U.S. Geological Survey Fact Sheet 178-97. U.S. Geological
Survey, Reston, VA.
Speiran, G.K. 2010. Effects of groundwater-flow paths on nitrate concentrations across two
riparian forest corridors. JAWRA 46(2):246-260.
Sprague, E., D. Burke, S. Claggett, and A. Todd. 2006. The State of Chesapeake Forests. The
Conservation Fund, Arlington, VA.
Strahler, A.N. 1957. Quantitative analysis of watershed geomorphology. American Geophysical
Union Transactions 38:913-920.
Sweeney, B.W. 1992. Streamside forests and the physical, chemical, and trophic
characterisitics of piedmont streams in eastern North America. Water Science and
Technology 26:2653-2673.
Sweeney, B.W. 1993. Effects of streamside vegetation on macroinvertebrate communities of
White Clay Creek in Eastern North America. In Proceedings of the Academy of Natural
Sciences of Philadelphia 144:291-340.
Sweeney, B.W. 2002. Streamside forests and the physical, chemical, and trophic characteristics
of Piedmont Streams in Eastern North America. Water Science and Technology
26:2653-2673.
Sweeney, B.W., and J.G. Elaine. 2007. Resurrecting the in-stream side of riparian forests.
Journal of Contemporary Water Research and Education 136:17-27.
Sweeney, B.W., S.J. Czapka, and L.C.A. Petrow. 2007. How planting method, weed abatement,
and herbivory affect afforestation success. South. J. Appl. For. 31(2) 2007.
Sweeney, B.W., S.J. Czapka, and T. Yerkes. 2002. Riparian forest restoration: Increasing
success by reducing plant competition and herbivory. Restor. Ecol. 10(2):392-400.
Sweeney, B.W., T.L. Bott, J.K. Jackson, LA. Kaplan, J.D. Newbold, L.J. Standley, W.C.
Hesslon, and R.J. Horwitz. 2004. Riparian deforestation, stream narrowing, and loss of
stream ecosystem services. PNAS 101(39) 2004.
Tjaden, R.L., and G.M. Weber. 1998a. Riparian Buffer Management: An Introduction to the
Riparian Forest Buffer. Fact Sheet 724. Maryland Cooperative Extension, University of
Maryland, College Park, MD.
5-46 Chapter 5. Riparian Area Management
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
Todd, A. 2002. Nutrient Load Removal Efficiencies for Riparian Buffers and Wetland
Restoration. U.S. Department of Agriculture Forest Service, Northeastern Area, State and
Private Forestry, Annapolis, MD, on behalf of the Forestry Work Group.
Tomer, M.D., D.E. James, and T.M. Isenhart. 2003. Optimizing the placement of riparian
practices in watershed using terrain analysis. J Soil Water Conserv 58:198-206
USDI (U.S. Department of the Interior). 1998. Riparian Area Management: Process for
Assessing Proper Functioning Condition. Technical Reference 1737-9. U.S. Department of
the Interior, Bureau of Land Management Service Center, Denver, CO.
USEPA (U.S. Environmental Protection Agency). 1996. Protecting Natural Wetlands: A Guide to
Stormwater Best Management Practices. EPA-843-B-96-001. U.S. Environmental
Protection Agency, Office of Water, Washington, DC.
USEPA (U.S. Environmental Protection Agency). 2005. National Management Measures to
Protect and Restore Wetlands and Riparian Areas for the Abatement ofNonpoint Source
Pollution. EPA 841-B-05-003. U.S. Environmental Protection Agency, Office of Water,
Washington, DC.
USEPA (U.S. Environmental Protection Agency). 2006. Wadeable streams assessment: A
collaborative survey of the nation's streams. EPA 841-B-06-002. U.S. Environmental
Protection Agency, Washington, DC.
Vidon, P., C. Allan, D. Burns, T. P. Duval, N. Gurwick, S. Inamdar, R.d Lowrance, J. Okay,
D. Scott, and S. Sebestyen. 2010. Hot spots and hot moments in riparian zones: Potential
for improved water quality management. JAWRA 46(2):278-298.
VDEQ (Virginia Department of Environmental Quality). 2009. 9 VAC 25-260 Virginia Water
Quality Standards with Amendments Effective August 20, 2009. Statutory Authority
§ 62.1-44.15 3a of the Code of Virginia. Virginia State Water Control Board.
VDCR (Virginia Department of Conservation and Recreation). 2010. A Virginia Priority...A Local
Option, . Accessed February 2010.
Vought, L.B., M.J. Dahl, C.L. Pedersen, and J.O. Lacoursiere. 1994. Nutrient retention in
riparian ecotones. Ambio 23(6):343-348.
Welsch, D. 1991. Riparian Forest Buffers: Function and Design for Protection and Enhancement
of Water Resources. NA-PR-07-91. U.S. Department of Agriculture Forest Service,
Radnor, PA.
Wlliams, M. 1989. Americans and their Forest: A Historical Geography. Cambridge University
Press, Cambridge, U.K.
Chapter 5. Riparian Area Management 5-47
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
Wondzell, S.M., and F.J. Swanson. 1996. Seasonal and storm dynamics of the hyporheic zone
of a 4th-order mountain stream. I: Hydrologic processes. J North Am Benthol Soc 15:3-19.
5-48 Chapter 5. Riparian Area Management
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
Chapter 6.
Decentralized Wastewater Treatment
Systems
Contents
1 Nitrogen-Reduction Implementation Measures 6-3
2 Introduction and Background 6-6
3 Nutrient-Reduction Processes for the Decentralized Wastewater Sector 6-9
3.1 Nitrogen 6-9
3.2 Nitrogen Pretreatment 6-9
3.3 Phosphorus 6-10
3.4 Permeable Reactive Barriers 6-11
3.5 System Configuration 6-12
4 Treatment Technologies and Costs 6-13
4.1 Conventional Systems 6-15
4.2 Land/Vegetative Treatment Systems 6-15
4.3 Suspended Growth Systems 6-15
4.4 Attached Growth Aerobic Systems 6-16
4.5 Add-On Anoxic Filters with a Carbon Source 6-17
4.6 Composting Toilet Systems 6-18
4.7 Cluster Treatment Systems 6-19
4.8 Soil Dispersal Systems 6-19
4.9 Effluent Reuse 6-20
5 Wastewater Planning and Treatment System Management 6-23
5.1 Public Education and Involvement 6-23
5.2 Planning 6-24
5.3 Performance Requirements 6-24
5.4 Recordkeeping, Inventories, and Reporting 6-25
Chapter 6. Decentralized Wastewater Treatment Systems 6-1
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
5.5 Financial Assistance and Funding 6-25
5.6 Site Evaluation 6-25
5.7 System Design 6-26
5.8 Construction/Installation 6-26
5.9 Operation and Maintenance 6-27
5.10 Residuals Management 6-27
5.11 Training and Certification/Licensing 6-27
5.12 Inspections and Monitoring 6-28
5.13 Corrective Actions and Enforcement 6-28
6 References 6-30
6-2 Chapter 6. Decentralized Wastewater Treatment Systems
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
1 Nitrogen-Reduction Implementation Measures
The U.S. Environmental Protection Agency (EPA) recommends protecting surface waters in the
Chesapeake Bay watershed from nitrogen (N) discharged by decentralized wastewater
treatment systems by using N-reduction technologies and enhanced system management.
Implementation Measures:
D-l. Specify the following risk-based, N-removal performance levels for all new
and replacement individual and cluster systems:
• 20 milligrams per liter (mg/L) total nitrogen (TN) standard* for all new
subdivisions and commercial and institutional developments and all
system replacements throughout the Chesapeake Bay watershed.
• 10 mg/L TN standard* for all new developments and all system
replacements in sensitive areas—i.e., between 200 and 1,000 feet of the
ordinary high water mark of all surface waters, or between 200 and
500 feet of an open-channel MS4.
• 5 mg/L TN standard* for all new developments and system replacements
in more sensitive areas—i.e., between 100 and 200 feet of the ordinary
high water mark of all surface waters, or between 100 and 200 feet of an
open-channel MS4.
• 100-foot setback from surface waters and open channel MS4s for all
effluent dispersal system components.
D-2.
D-3.
* Effluent standards can be met by either system design or
performance, as verified by third-party design review or field
verification. Except in sandy or loamy sand soils, a 5 mg/L N
reduction credit is given when using time-dosed, pressurized
effluent dispersal within 1 foot of the ground surface and
more than 1.5 feet above a limiting soil/bedrock condition.
Ensure wastewater treatment performance effectiveness and cost efficiency
by using cluster systems with advanced N-removal technology sufficient to
meet the standards specified above for all newly developed communities
and densely populated areas.
Sustain treatment system performance in perpetuity through management
contracts with trained and certified operators for all advanced N-removal
Chapter 6. Decentralized Wastewater Treatment Systems
6-3
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
systems, and responsible management entity (RME) operation and
maintenance (O&M) for all cluster and nonresidential systems. RMEs
include sanitation districts, special districts, and other public or private
entities with the technical, managerial, and financial capacity to assure long-
term system performance.
D-4. Preserve long-term treatment system performance with management
practices designed to protect system investments, by doing the following:
• Conducting GIS-based inventories of all individual and cluster
(i.e., decentralized) wastewater systems in all areas that drain into the
Chesapeake Bay or its tributaries. Inventory information includes system
location (i.e., latitude/longitude), type, capacity, installation date, owner,
and relevant information on complaints, service (including tank pump-
out), repairs, inspections, and dates. Inventory data is stored
electronically in a format amenable for use in watershed studies, system
impacts analyses, and supporting general management tasks. EPA offers
The Wastewater Information System Tool (TWIST) (USEPA 2006) as a free
resource for managing that information in a user-friendly database.
Health departments, state agencies, RMEs and others can adapt, amend,
or otherwise modify TWIST without restriction or obligation.
• Requiring inspections for all systems on a schedule according to
wastewater type, system size, complexity, location, and relative
environmental risk. At a minimum, qualified inspectors inspect all
systems at least once every 5 years and inspect existing systems within
sensitive areas at least once every 3 years. Inspect advanced treatment
systems, cluster systems, and those serving commercial, institutional, or
industrial facilities at least semiannually and manage such systems under
an O&M agreement or by an RME. Inspections are consistent with EPA
management guidelines for individual and cluster systems. A service
professional or other trained personnel conducts routine monitoring of
all systems, and periodic effluent sampling for cluster and nonresidential
systems, on the basis of system type, operating history, manufacturer's
recommendations, and other relevant factors.
• Repairing or replacing all malfunctioning systems when discovered, with
new or replacement technologies capable of meeting the N-removal
standards specified above.
• Requiring reserve areas for installing a replacement soil dispersal system
that is equal to at least 100 percent of the size of the original effluent
6-4 Chapter 6. Decentralized Wastewater Treatment Systems
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
dispersal area. Treatment systems using effluent time-dosing (i.e., not
demand-dosing) to the soil can have reserve areas equal to at least
75 percent of the total required drainfield area. Systems with pressurized
drip effluent dosing or shallow pressurized effluent dispersal and those
with dual drainfields operated on active/rest cycles (i.e., alternating
drainfields) can have reserve areas equal to at least 50 percent of the
original required dispersal area.
D-5. Remove nitrate in subsurface effluent plumes that enter surface waters by
using effective, low-cost technologies such as permeable reactive barriers
(PRBs). PRBs are low-cost, pH-controlled trenches filled with sand and a
degradable carbon source, such as sawdust, shredded newspaper, or wood
chips, designed to intercept groundwater plumes and reduce the TN
concentration via denitrification.
Chapter 6. Decentralized Wastewater Treatment Systems 6-5
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
2 Introduction and Background
Individual on-site and cluster (decentralized) wastewater systems treat household and
commercial wastes in suburban, exurban, and rural areas throughout the Chesapeake Bay
watershed. The Chesapeake Bay Program (USEPA 2009) estimates that about 25 percent of
the homes in the watershed—2.3 million total—rely on these systems, which disperse treated
effluent to the soil. EPA predicts that decentralized system installations will increase over the
next 20 years by about 35 percent (i.e., 800,000 new systems), eventually reaching 3.1 million
(USEPA 2009).
Nearly all the solids and phosphorus (P) discharged from decentralized wastewater systems are
retained by the soil, through physical filtration, adsorption, and precipitation processes
(USEPA 2004), although release of P into the environment is a concern in sandy soils under
certain conditions, especially with poor vertical separation distance with groundwater (Bussey
1996). However, N in wastewater is ultimately converted to nitrate upon infiltration into aerobic
soils, a stable, soluble, and highly mobile form of this nutrient that negatively affects
groundwater and surface water quality. For those reasons, in this guidance EPA focuses on
implementation measures to reduce N.
Decentralized wastewater systems contribute approximately 12.5 million pounds of N to the
Chesapeake Bay annually, or about 4.5 percent of the total load. According to current
Chesapeake Bay nutrient loading models, most of the N load from such systems—about
60 percent—comes from the Potomac and Susquehanna river drainage areas within
Pennsylvania, Virginia, and Maryland. With 800,000 new systems predicted over the next
15 years, significant reductions in N loads from new and existing systems are needed.
The Chesapeake Bay nutrient and sediment reduction goals include decreases in current and
future pollutant loads from decentralized treatment systems. A new generation of "hardware and
software"—treatment technologies and management practices—are needed to achieve the
reductions. This section describes those technologies, management practices, and associated
implementation measures. Implementation measures for achieving the reductions include
installing treatment units with optimal N-removal capabilities in sensitive areas near surface
waters; using standard N removal systems in other areas; and ensuring that all treatment
systems are appropriately operated, maintained, and managed. The measures encompass a
range of treatment technologies, planning and performance considerations, and management
actions needed to address N export from decentralized systems.
6-6 Chapter 6. Decentralized Wastewater Treatment Systems
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
The implementation measures described in this chapter support two primary goals for
addressing N inputs to the Chesapeake Bay from these systems:
• Prevent further impairment of the Chesapeake Bay by significantly reducing N levels in
wastewater from new residential, commercial, and institutional developments using
decentralized systems
• Reduce N inputs to the Chesapeake Bay from existing individual and cluster wastewater
systems by replacing malfunctioning systems with better-performing technologies and by
managing all systems to ensure long term performance
Implementation measures to achieve those goals include repairing or replacing malfunctioning
systems, targeting high-risk systems in sensitive areas for replacement with advanced treatment
units, clustering replacement systems where possible to implement better-performing and more
efficient community treatment facilities, inspecting all systems throughout the Chesapeake Bay
watershed, and installing PRBs where technically and economically feasible to reduce N
concentrations in targeted effluent plumes. Those approaches are based on more than
2 decades of research and field studies on decentralized system applications.
Key findings on system performance, effects on groundwater, and the opportunities presented
by next-generation treatment technologies are summarized in the Final Report for the La Pine
National Decentralized Wastewater Treatment Demonstration Project (Rich 2005), a joint effort
of EPA and other federal, state, and local agencies:
The groundwater investigations have found significant existing nitrogen pollution
and the 3-D model has predicted extensive future contamination of the aquifer.
The model also predicted, based on the field performance of denitrifying systems
in the project, that contamination could be slowed or stopped using onsite
wastewater treatment technologies, and that, as the region is retrofitted with
denitrifying technologies, the existing contamination would be flushed from the
groundwater system via existing natural discharge points.
The field test program, in addition to identifying systems that can remove a large
proportion of the nitrogen in residential wastewater, found that conventional
systems are not protecting the aquifer from nitrate contamination. Conventional
systems that were previously thought to denitrify up to 50% of the nitrate
discharged from septic tanks were found to achieve significantly less
denitrification when process and environmental variables were accounted for.
The La Pine Project, EPA's Environmental Technology Verification (ETV) program, the National
Sanitation Foundation standards program, and other research efforts across the country have
Chapter 6. Decentralized Wastewater Treatment Systems 6-7
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
identified and tested a number of denitrifying wastewater systems and found that performance
varies considerably. However, some systems do perform optimally in removing TN from the
effluent—e.g., to concentrations lower than 5 mg/L—and others are capable of N effluent levels
in the 10 and 20 mg/L range.
Higher treatment performance levels are needed in sensitive areas to protect or restore surface
water quality. Research and field studies confirm that effluent plumes with elevated nitrate levels
move laterally over long distances—i.e., greater than 300 feet in unconfined, sandy aquifers
(Walker et al. 1972; Robertson and Cherry 1992). N concentrations in effluent plumes are
affected by soil oxygen levels, soil composition, plant uptake, labile carbon content, travel
distance, rate of movement, mixing, and other factors. The measures specified in this chapter
include descriptions of treatment and dispersal systems that can meet the performance
standards needed to protect the Chesapeake Bay and its tributaries and include more stringent
treatment levels in sensitive areas near waterbodies. Such measures are consistent with efforts
in the states that have already been adopting treatment zone setbacks and treatment standards
to address N and other pollutants in coastal areas (Joubert et al. 2003).
6-8 Chapter 6. Decentralized Wastewater Treatment Systems
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
3 Nutrient-Reduction Processes for the
Decentralized Wastewater Sector
Nutrients—primarily P and N—are usually present in significant levels in domestic and
commercial wastewater. Nutrient treatment and removal involve processes that occur either in
treatment system components or in the receiving environment, as summarized below.
3.1 Nitrogen
N is the primary pollutant of concern along the coastal areas of the eastern United States,
including the Chesapeake Bay. N discharges are a concern both as a drinking water
contaminant (nitrate) and as an aquatic plant nutrient, particularly in N-sensitive surface waters
and nearshore marine waters. N is not readily or consistently removed in conventional individual
and cluster soil-based systems because conventional soil-discharging systems are not designed
to remove N, and most soils have a limited capacity to retain or remove N. Organic N in
wastewater is generally converted to ammonium N in the septic tank. Ammonium N is quickly
nitrified as the wastewater infiltrates the aerobic soil. Nitrate-N is stable, soluble, and highly
mobile in the subsurface environment. Biological denitrification of the nitrate is usually limited
because the soil is often aerobic near the ground surface and usually has very little organic
carbon, which is required by heterotrophic denitrifying microorganisms. Therefore, where N
removal is required for dispersal, pretreatment that achieves both nitrification and denitrification
is usually necessary before the wastewater is dispersed to the soil.
3.2 Nitrogen Pretreatment
Many reasonably priced natural and mechanical pretreatment systems, specifically designed for
individual and cluster systems, are available today. The most popular example of such systems
is the recirculating media filter, with timed pressure-dosing effluent dispersal. The filter media is
typically sand, gravel, textile or peat. A portion of the filtered effluent is recycled back to the
septic tank (or pump/recirculating tank) and filter several times before discharge. Denitrification
is supported by the low-oxygen, high-carbon environment that exists in the recirculating tank.
The systems are able to consistently remove an average of 50 percent or more of the TN in the
septic tank effluent—reducing the TN from a typical influent range of 40-50 mg/L for single
family homes to 15-20 mg/L (Otis 2007; USEPA 2002a; Jenssen and Siegrist 1990; Higgins et
al. 2002; Smith et al. 2008; Rich et al. 2003).
To achieve TN levels of 3-5 mg/L and lower, an additional denitrifying unit process is usually
installed to augment the pretreatment system. To sustain a denitrification process capable of
Chapter 6. Decentralized Wastewater Treatment Systems 6-9
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
high levels of N removal, the nitrified effluent from the pretreatment process must be exposed to
a reactive carbon source in a low-oxygen environment before discharge. For larger installations,
methanol, acetic acid, molasses, or other organic chemicals are added to the anaerobic reactor.
However, the cost of building, operating, and maintaining an external chemical feeding system,
coupled with the cost of chemicals, power for a feed pump, controls, and chemical storage
increase N-removal expenses substantially.
Carbon sources are not equal in terms of O&M requirements. For example, methanol is very
sensitive to under- or over-dosing, and thus requires special attention to ensure that the system
is monitored enough to control dosing for optimal N-removal and biochemical oxygen demand
control. By contrast, sawdust and newspapers need to be replaced only when effluent N breaks
through (i.e., the denitrification capacity of the sawdust or newspaper has been exhausted).
Proprietary denitrifying units, which avoid the need for additional feed pumps, controls, and
chemicals, are now available. Such units include a slowly degradable organic material in the
reactor tank that can last several years. Field testing has documented TN effluent
concentrations of 3-5 mg/L and even lower (Smith et al. 2008; Lombardo et al. 2005).
Further N removal occurs in the soil, particularly when pretreated effluent is dispersed uniformly
via alternating dose/rest cycles. Plant uptake of N, soil oxygen levels, carbon sources,
temperature, and residence time are key factors in N-removal levels during this final stage of
treatment, which are estimated in the 50 percent reduction range (Long 1995; Otis 2007).
Additionally, some soils contain sufficient labile carbon to denitrify effluents regardless of the
method of dispersal (Anderson 1998; Gold et al. 2002; Starr and Gillham 1986; Bushman 1996;
Hiscock et al. 1991). Other important variables could include seasonal use (Postma 1992),
in-stream processes, including the matrix through which the groundwater enters nearby surface
waters (Birgand 2000; Stewart and Reneau 1984), and the distance from the source to the
receiving surface waters (Stacey 2002). One study from the U.K. (Hiscock et al. 1991) estimates
that average groundwater carbon content would account for removal of 3 mg/L of nitrate.
3.3 Phosphorus
Approximately 20 to 30 percent of the P in wastewater is removed in septic tanks (Lombardo
2006). P removal in soil effluent dispersal systems is achieved primarily by mineral precipitation.
The process involves sorption and complex biogeochemical mechanisms that rely on dissolved
P mineralization with iron, calcium, and aluminum (Tyler et al. 2003; Stone Environmental 2005;
Lombardo 2006). The stability of those processes is influenced by pH, redoximorphic conditions,
and the chemistry of aluminum and iron. The soil's capacity to remove P is significant both
spatially and temporally. Sorption can be reversible—as with sands, or relatively permanent, as
in soils high in iron oxides.
6-10 Chapter 6. Decentralized Wastewater Treatment Systems
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
In general, most regions of the Chesapeake Bay watershed have soils that retain high levels of
P from decentralized systems. Areas where soil-based, P-removal rates are low include highly
permeable soils, such as sands, loamy sands, and soils very high in gravel. In areas with
sufficient soil P-removal capacity, saturation fronts of P move only inches or less per year.
Wastewater system designers maximize P-removal rates by locating the infiltration system in
medium- to fine-textured soils that are as far from surface waters as possible, and extending the
infiltration system along the topographic contour of the installation site. Also, uniform dosing and
resting dispersal by pressure or drip distribution will optimize P removal in the soil by increasing
the contact time between the effluent and the soil.
If native soils are not amenable to adsorption removal, other adsorption methods are available
(Stone Environmental 2005; Dimick et al. 2006; USEPA 2002a). Although some P can be
removed by pretreatment systems that contain high concentrations of adsorptive elements or by
biological P removal, soil adsorption is by far the most common and least expensive means of
removal. Where soils are inadequate for P removal, mound systems that use more appropriate
soil (possibly imported) might be required. System use over time slowly reduces the capacity of
the soil to remove P.
3.4 Permeable Reactive Barriers
Specific types of PRBs have been developed to remove nitrate from groundwater plumes that
would otherwise adversely affect surface water quality. PRBs consist of a trench filled with a
degradable carbon source (e.g., sawdust, newspaper) and are sited to intercept high-nitrate
groundwater plumes (WE&T 2009) before they enter surface waters (Figure 6-1). As the plumes
pass through the low-oxygen,
carbon-rich barrier, bacteria
break down nitrate molecules to
use the oxygen for cell
respiration. In areas where
receiving waters are already
eutrophied, the trenches
provide immediate relief by
removing nitrate from the
incoming groundwater. water Table
Addressing the source of the
high-nitrate plume (i.e., densely
sited septic systems) would
also produce results, but any
measureable effects would
likely take several years
GWFlow
'ermeable Reactive Barrier
Source: USEPA 1998
Figure 6-1. PRB conceptual approach.
Chapter 6. Decentralized Wastewater Treatment Systems
6-11
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
because of slow effluent plume movement in most soils and could be more expensive and
require more maintenance than installing PRBs.
PRBs are typically installed as long, narrow trenches perpendicular to the incoming plume and
parallel to the shoreline. The most effective ones for removing nitrate from plumes are filled with
a carbon-based media mix that controls for changes in pH. Such systems have been
successfully demonstrated in North America and Europe (Vallino and Foreman 2008; Robertson
and Cherry 1995; Lombardo et al. 2005; USEPA 1998). Costs range from about $5,000 to
$15,000 per equivalent dwelling unit (i.e., in the plume sourcing area), depending on soils,
geology, depth to groundwater, subsurface hydrology, construction access, existing
infrastructure, and other factors. Zero valent iron, now used for some industrial wastewater
treatment applications, has been studied as a nutrient-removal media in PRBs and other system
components. Obstacles with this technology include reduction of nitrate to ammonia rather than
N gas and relatively high costs (Cheng 1997). New variations of this technology hold promise
for removing some of these obstacles (Lee et al. 2007).
3.5 System Configuration
As noted above, a certain level of treatment process sophistication and soil discharge technique
(e.g., pressure dosing, drip dispersal) are required for optimum N removal. Their cost in terms of
both hardware and management needs can be significantly mitigated through the use of cluster
systems that treat wastewater from multiple homes or businesses. Cluster systems, also called
community or distributed systems, have become extremely popular in areas where high levels
of wastewater treatment are required, where space is too limited for on-site conventional soil-
discharging systems, and local funding capacity precludes conventional sewage collection and
treatment (see Section 4.6).
It should be noted that soil-discharging wastewater systems that have the capacity to serve 20
or more people per day are defined by EPA as Class 5 underground injection wells and are
therefore subject to permitting and other requirements for large-capacity septic systems under
the federal Safe Drinking Water Act. Further, any decentralized system that accepts waste other
than sanitary wastewater (such as industrial waste) is an Underground Injection Control (UIC)
Class 5 Injection Well. UIC regulatory information for large-capacity septic systems is posted at
http://www.epa.gov/safewater/uic/class5/types Ig capacity septic.html.
6-12 Chapter 6. Decentralized Wastewater Treatment Systems
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
4 Treatment Technologies and Costs
Key considerations in treatment system selection are wastewater flow, strength (i.e.,
biochemical oxygen demand), the presence of nonconventional organic or inorganic
constituents, the sensitivity of the receiving environment, and the capacity of system managers
to operate and maintain it over the long term. Given those factors, both the selection and
ongoing use of a specific technology is driven by management considerations. For example,
wastewater characterization and assessment of the receiving environment are planning-level
activities that result in establishing performance standards, which begin to identify the narrow
range of treatment technology options and related design considerations. Once a specific
system is selected, construction oversight, operation, inspection, maintenance, and residuals
removal—all management program elements—become paramount in ensuring perpetual
performance.
The La Pine Decentralized Wastewater Demonstration Project (Rich 2005) has provided some
of the most comprehensive field data on the performance of various system types. The
project—funded by EPA and supported by the Deschutes County, Oregon, Environmental
Health Division; Oregon Department of Environmental Quality; and the U.S. Geological
Survey—monitored system performance between 1999 and 2005 (see Figure 6-2 and
Table 6-1). System performance was found to be affected by a number of variables, but in
general the level of analysis provides insight on the range of pollutant removal that can be
expected from the various system types. The figure and table that follow summarize key data
from the project; detailed performance results, system descriptions, and other information are
available in the final project report (Rich 2005).
The subsections that follow discuss the main classes of treatment system technologies. The
final section of this chapter summarizes management program elements that support the
implementation measures provided at the beginning of this chapter. Table 6-2 provides
examples of biological N-removal performance from the literature for a variety of technologies.
Table 6-3 contains details on specific treatment systems described in the subsections below.
Chapter 6. Decentralized Wastewater Treatment Systems 6-13
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
NrREX
Biokreisel
AX-20
RX-30
Amphidrome
EnviroServer
FAST, w/0 RV
Navadic
Dyno2
Puraflo
Lined Sand FJIter
Bottomless Sand Filter
NiteLess
Septic Tank
IDEA
mg/L [
LJ.
~jL
BH
i
H+
14.1
14.0
14.7
17.0
16.3
18.8
1
l-l-l
24.2
26.3
1
HH
1
W-1
1
l-H
33.5
32.3
34.9
36.4
35.1
J_
48.0
I — 1 50 2
1 51.3
l-l-l *1 1
49.8
50.2
|
l-l-l
1
Eh
61.0
61.0
63.0
66.1
60. 9
1 1 1 1 1 1 1 1=
) 10 23 30 40 50 60 70 80 90
• Median Total Nitrogen
D Mean Total Nitrogen
1(
)0 1
o 1:
3
i
96.8
SO 1'
10
Source: Rich 2005.
Figure 6-2. Effluent TN concentrations for systems tested in the La Pine Project.
Table 6-1. System components and type classifications for Figure 6-2
System component/type
Septic Tank
Lined Sand Filter
Bottomless Sand Filter
AdvanTex AX-20
AdvanTex RX-30
Puraflo
Dyno2
Amphidrome
Biokreisel
EnviroServer
FAST Bio-Microbics
IDEA
Nayadic
NiteLess
NITREX
General classification
Primary treatment vessel
Attached growth, sand media
Attached growth, sand media
Attached growth, textile media
Attached growth, textile media
Attached growth, peat media
Attached growth, gravel media, wetland polishing
Attached growth/suspended growth hybrid
Attached growth/suspended growth hybrid
Attached growth/suspended growth hybrid
Attached growth/suspended growth hybrid
Suspended growth
Suspended growth
Suspended growth with add-on anoxic filter
Add-on anoxic filter
6-14
Chapter 6. Decentralized Wastewater Treatment Systems
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
4.1 Conventional Systems
Conventional treatment systems featuring septic tanks and soil infiltration systems are the most
commonly used wastewater treatment technologies. The soil dispersal system facilitates aerobic
treatment, degradation, filtration, and adsorption of contaminants not treated or retained by the
septic tank. However, N removal is somewhat limited, with TN concentrations before soil
application typically in the 40-50 mg/L range. In sandy soils with little organic content, high
oxygen levels, and poor downgradient mixing, N concentrations can remain high even after
several hundred feet of effluent plume movement (Walker et al. 1973; Robertson and Cherry
1992; Cogger 1988; Joubert et al. 2003). Given the low N removal rates of conventional
systems (i.e., averaging 20 percent TN removal; Otis 2007; Smith et al. 2008; Jenssen and
Siegrist 1990), they are no longer appropriate for use in new communities or densely developed
areas in the Chesapeake Bay watershed.
4.2 Land/Vegetative Treatment Systems
Land treatment systems, such as spray irrigation systems, are permitted in some places but
have not been widely used because of their large land area requirements (USEPA 2000). In
general, such vegetative treatment systems have shown poor performance with regard to N
removal. However, in recent years, significant advances have been made. The Living Machine,
a proprietary decentralized wastewater treatment system has been used successfully for large-
capacity applications, such as schools. While the system delivers advanced N removal, it relies
on multiple treatment processes including anaerobic and aerobic reactors, a clarifier, and an
ecological fluidizer bed (USEPA 2002b), which drive up the cost. Eco-machines are similar in
concept to The Living Machine and are capable of advanced N removal. Costs for both of these
technologies make sense for only fairly large-capacity applications. They are not practical for
individual residential systems but could be useful for cluster and large system applications.
4.3 Suspended Growth Systems
Suspended growth systems, such as activated sludge-based aerobic treatment units (ATUs),
are generally effective in nitrifying septic tank effluent. Denitrification is somewhat limited, but
can be aided by process controls (e.g., recirculation) and effluent dispersal via time-dosing into
the upper soil horizon (Stewart 1988). Aerobic units that feature aeration that periodically stops
and starts show improved denitrification. Sequencing batch reactors, which first fill and then
draw, in alternating aerobic/anoxic cycles in a single tank might also meet the 20 mg/L
recommended effluent limit for areas more than 1,000 feet from surface waters in the
Chesapeake Bay watershed, when effluent is dispersed to the soil via time-dosed pressure
application (Washington State Department of Health 2005). Capital costs for conventional
on-site suspended growth systems range from $7,500 to $15,000 per equivalent dwelling unit
Chapter 6. Decentralized Wastewater Treatment Systems 6-15
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
(EDU), with O&M expenses of $400 to $800 per EDU per year when all suggested O&M tasks
are performed (Tetra Tech 2007).
N removal in larger cluster applications of suspended growth systems (i.e., > 200 homes) can
be enhanced by incorporating a membrane bioreactor process (MBR) unit, which screens
wastewater through very small pore-size filters. MBRs are more common to centralized
treatment facilities because of operating costs and economy of scale issues. However,
individual home-sized and small cluster units are beginning to be developed for the U.S. market
(e.g., BioBarrier, ZeeWeed; WERF 2006). The high-quality effluent provides opportunities for
treated water reuse. Cost and performance data for individual and small cluster applications of
MBRs are not widely available and are likely to vary greatly. Energy costs, particularly to
operate the pumping components, are often significant, especially in smaller system
applications (USEPA 2007).
4.4 Attached Growth Aerobic Systems
These systems (sometimes called trickling filters or media filters) use natural aeration instead of
mechanical, produce less sludge for disposal, and require less power and O&M than the
suspended growth units in performing the same tasks. All the systems listed in Table 6-3 are
varieties of attached growth system types. Like suspended growth systems, attached growth
treatment units also require a recirculation step to meet more stringent TN-removal objectives.
Commercially available systems come in lightweight packages and employ lightweight media for
easy installation. They also require about 20 percent less physical footprint than typical trickling
filters. When properly loaded and operated, they can produce very high nitrification levels that
must be followed by a denitrification step to exceed the typical 50 percent N-removal rate.
Attached growth systems are also often quite stable compared with suspended growth
processes, which might be important, particularly for decentralized systems serving periodically
or seasonally used facilities. On-site capital costs are slightly higher in general than the
suspended growth ATUs ($10,000-$16,000 per EDU), but O&M costs are significantly less,
e.g., about $200-$300 per EDU per year (USEPA 2010; Tetra Tech 2007).
N removal in attached growth media filters can be optimized through internal treatment system
process controls. Single-pass media filters—sand filters, textile filters, peat systems, mounds,
and other packed media bed units—achieve excellent nitrification levels but generally do a poor
job with denitrification unless some, or all, of the effluent passes through a carbon-rich, low-
oxygen environment after the nitrification stage. That can be accomplished by recirculating a
portion of the effluent back to the septic tank or a pump tank, or by adding a denitrification unit
to the system, or both. Media filters have a long record of excellent performance, with
nitrification rates as high as 95 percent (Otis 2007; Smith et al. 2008; USEPA 2002a). The
treatment process is stable year-round and can be employed through either custom-built,
6-16 Chapter 6. Decentralized Wastewater Treatment Systems
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
nonproprietary engineered systems or commercial units that can be installed in a single day.
Capital costs for single-pass filters range from $5,500 to $13,000 per EDU, with O&M expenses
of $200 to $400 per EDU per year (USEPA 2010; Tetra Tech 2007).
Recirculating media filters have been in use for many years and feature high nitrification rates
with about 50-70 percent TN reduction. The systems recycle part of the effluent back to the
septic tank or the recirculating tank, where the anoxic environment and available carbon
facilitate denitrification processes. Design considerations include the ratio of effluent recirculated
and the configuration of the recycle plumbing, i.e., ensuring that the recycled effluent is
discharged to a tank location with low oxygen and some carbon. TN effluent concentrations can
be as low as 10 mg/L, which can be further reduced in the soil by using time-dosed, pressure-
drip effluent dispersal. Engineered systems and proprietary units are widely available and can
serve single homes or large subdivisions. Capital costs for recirculating systems range from
$9,500 to $20,000 per EDU, with O&M expenses of $350 to $600 per EDU per year (USEPA
2010; Tetra Tech 2007; Washington State Department of Health 2005).
4.5 Add-On Anoxic Filters with a Carbon Source
Optimal denitrification can be achieved by passing nitrified effluent through a low-oxygen,
carbon-rich environment before soil dispersal. Engineered and proprietary systems featuring
add-on anoxic filters with an external carbon source (e.g., methanol, sawdust, newspapers)
have performed successfully in single-home and cluster applications. For example, at least one
commercially available product (NITREX) regularly produces effluent with N concentrations of
less than 5 mg/L (Heufelder et al. 2007, see also Figure 6-2 and Table 6-2). Others claim to
have similar systems with comparable performance, although, to date, independent field
verification is lacking. NITREX relies on a passive nitrate remediation biofilter unit that uses a
processed wood by-product as the filter medium. Other system designs discussed above can
approach that level when paired with time-dosed, shallow pressurized dispersal. Capital costs
for add-on denitrification systems range from $3,500 to $7,000 and more per EDU, with O&M
expenses of less than $100 per year (Washington State Department of Health 2005). Note that
those are added costs and do not include costs for the septic tank, nitrification process unit, or
soil dispersal system—just the add-on component.
Chapter 6. Decentralized Wastewater Treatment Systems 6-17
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
Table 6-2. Examples of biological N removal performance from the literature
Technology examples
TN removal efficiency
(%)
Effluent TN
(mg/L)
Suspended growth
Aerobic units w/ pulse aeration
Sequencing batch reactor
25%-61%a
60%b
37-60a
15.5b
Attached growth
Single-Pass Sand Filters (SPSF)
Recirculating Sand/Gravel Filters (RSF)
Multi-Pass Textile Filters (AdvanTex AX20)
RSF w/ Anoxic Filter
RSF w/ Anoxic Filter & external carbon source
RUCK system
NITREX
8%-50%c
15%-84%d
64%-70%e
40%-90%f
74%-80%s
29%-54%h
96% ]
30-60C
10-47d
3-55e
7-23f
10-1 3s
18-53h
2.2
Source: Adapted from Washington Department of Health 2005
Notes: Overall performance can vary, depending on system configuration and other factors. For detailed descriptions of
treatment processes and technologies, see
http://www.psparchives.com/publications/our work/hood canal/hood canal/n reducing technologies.pdf.
a. California Regional Water Quality Control Board 1997; Whitmeyer et al. 1991
b. Ayres Associates 1998
c. Converse 1999; Gold et al. 1992; Loomis et al. 2001; Nolte & Associates 1992; Ronayne et al. 1982
d. California Regional Water Quality Control Board 1997; Gold etal. 1992; Loomis et al 2001; Nolte & Associates 1992;
Oakley etal. 1999; Pilukand Peters 1994; Ronayne etal. 1982
e. NSF International 2009
f. Ayres Associates 1998; Sandy et al. 1988
g. Gold etal. 1989
h. Brooks 1996; Gold etal. 1989
j. Rich et al. 2003
4.6 Composting Toilet Systems
Composting toilet systems that contain and treat toilet wastes can reduce watershed N
discharges significantly, because such wastes account for 70-80 percent of the TN load in
domestic wastewater. Composting systems have been used successfully in both private and
public facility settings. Like all systems, they require appropriate design and ongoing
maintenance. A graywater treatment system is needed if the facility generates sink, laundry, or
other graywater, therefore adding to the cost. Capital costs for composting systems (and
excluding the cost of graywater systems) range from $2,500 to $10,000, with O&M expenses of
$50 to $100 per year (USEPA 1999). The single-house viability of such systems depends on
local codes and the owner's attitude, though acceptance and use of composting systems is
6-18
Chapter 6. Decentralized Wastewater Treatment Systems
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
increasing because of improved designs, performance, and lower maintenance requirements.
The systems are more frequently used in public settings, such as parks and campgrounds.
4.7 Cluster Treatment Systems
Generally, cluster systems collect wastewater from multiple houses through low-cost sewerage
and treat and disperse the effluent to soil-based dispersal systems similar to on-site systems.
Many homes and businesses can be served by a single treatment facility. Most cluster systems
feature septic tanks on each building lot; collection piping that operates via gravity, vacuum, or
pressure; a treatment facility with attached growth process units; and a soils-based dispersal
field for the effluent. Add-on anoxic denitrification filters can be included. Effluent is typically
dispersed to the soil under pressure (e.g., pressure, drip, time or demand dosing) to assure
uniform application throughout the larger drainfield. Collection technologies include grinder
pump systems, which macerate and transport all sewage; effluent sewers, such as the septic
tank effluent pump (STEP); the septic tank effluent gravity (STEG) collection system; and
vacuum systems.
Advanced treatment systems can facilitate local reuse of the treated effluent for toilet flushing,
irrigation, industrial purposes, or just be used to replenish aquifers. The cost of a cluster
collection system varies significantly according to the number of users, collection system
logistics, treatment facility design, land availability, materials, labor costs, and other factors.
Cluster systems can achieve economies of scale to provide high levels of treatment at costs
significantly less than individual systems and centralized sewer systems. New cluster systems
generally range from $10,000 to $18,000 per EDU in non-urbanized areas of new development,
with higher costs for retrofits in urban areas, depending on the treatment technology used
(USEPA 2010; Tetra Tech 2007). Replacement and retrofit systems have similar costs, but
collection system installation can drive costs higher. An RME with the technical, financial, and
managerial capacity to ensure viable, long-term, cost-effective performance is essential for
cluster system applications. Total system annual O&M costs range from $450 to $750 per EDU
per year (Tetra Tech 2007).
4.8 Soil Dispersal Systems
Gravity-based, soil dispersal systems generally include conventional perforated pipe, laid in
stone-filled trenches or purchased with Styrofoam beads surrounding the pipe and wrapped in
netting; and gravelless, open-bottomed leaching chambers. N removal in the soil increases
when effluent is dispersed in a time-dosed manner (i.e., dose/rest cycle) in the uppermost soil
horizon (i.e., within one foot of the ground surface). Time-dosed, pressure-drip dispersal in the
top 12 inches of soil has been credited with a 50 percent reduction in Tennessee (Long 1995),
making the option an important feature for achieving the performance standards recommended
Chapter 6. Decentralized Wastewater Treatment Systems 6-19
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
in this chapter. As in all effluent dispersal systems, maximizing the separation distance between
effluent application and restrictive soil boundaries (e.g., hardpan, bedrock, perched water
tables, seasonal high water tables) improves performance.
Another effluent-dispersal strategy that improves performance is the use of alternating soil
dispersal fields. Most conventional systems continuously load drainfields with effluent, resulting
in a gradual reduction of the soil's capacity to treat effluent over time. Alternating drainfields that
are used for 6 months then rested for 6 months improves the performance of the soil dispersal
system and should be favored over conventional drainfields. Such systems require relatively low
additional investment and can greatly extend the life of the soil dispersal system (Noah 2006).
Maintenance programs for such systems should be designed and implemented in concert with
the local health department or RME to ensure that flow-diversion devices are operated on
schedule. Because this strategy applies to conventional septic drainfields, this recommendation
applies primarily to areas of new development outside sensitive areas and subdivisions.
4.9 Effluent Reuse
Reusing treated wastewater system effluent can significantly reduce N discharge to the
environment. Many of the technologies suggested for advanced decentralized wastewater
treatment in the Chesapeake Bay watershed can, with adaptations, be used to produce
reclaimed water for beneficial reuses, including aquifer recharge, landscape irrigation, toilet
flushing, fire protection, cooling and other nonpotable indoor and outdoor purposes (USEPA
2004). When reclaimed water is used for irrigation, reuse can offset potable water demand by
augmenting supply while sequestering nutrients in vegetative matter and offsetting fertilizer use
(WERF 2010). Reclaimed water technologies generally include recirculating filtration systems
and membrane bioreactors, amended with disinfection systems (most commonly, chlorination or
ultraviolet disinfection or both), online monitoring systems, on-site storage, and sometimes
specific chemical feed systems for conditioning treated effluent to meet water quality demands
for specific reuses (e.g., pH adjustment for cooling water). Nonreactive dye injection is
sometimes required by building codes for reclaimed water to be used indoors. Costs for
decentralized reclaimed water systems are highly context-specific and dependent on the
intended reuse application, system size, and local or state regulatory requirements (WERF
2010) but can be assumed to add 50 percent to the costs of a more traditional decentralized
system.
6-20 Chapter 6. Decentralized Wastewater Treatment Systems
-------
Table 6-3. Products that have completed the EPA ETV process for N reduction in domestic wastewater from individual homes, as of May
2005
System name
Technology
Description of process
Performance
Cost
Waterloo Biofilter® Model 4-Bedroom
Waterloo Biofilter Systems, Inc.
143 Dennis St.: PO Box 100,
Rockwood, Ontario
Canada NOB 2kO
http://www.nsf.org/business/water quality
protection center/pdf/Waterloo-VS-
SIGNED.pdf
Fixed film trickling
filter.
The biofilter unit uses patented
lightweight open-cell foam that
provides a large surface area. Settled
wastewater from a primary septic tank
is applied to the surface of the biofilter
with a spray distribution system. The
system can be set up using a single
pass process (without any
recirculation of biofilter treated
effluent) or can use multi-pass
configurations. The ETV testing
results were generated by returning
50% of the biofilter effluent back to the
primary compartment of the septic
tank.
It averaged 62%
removal of TN with
an average TN
effluent of 14 mg/L
over the 13-month
testing period.
Earlier testing of
this product in a
single pass mode
demonstrated that it
could produce a
20-40% TN
reduction.
$13,000-$17,000 for total
system installation. The
Waterloo Biofilter unit only
would cost approximately
$7,000.
Amphidrome™ Model Single Family
System:
F.R. Mahony & Associates, Inc.
273 Weymouth St.
Rockland, MA 02370
http://www.nsf.org/business/water quality
protection center/pdf/Amphidrome VS.pdf
Submerged growth
sequencing batch
reactor (SBR) in
conjunction with an
anoxic/equalization
tank and a clear
well tank for
wastewater
treatment
The bioreactor consists of a deep bed
sand filter, which alternates between
aerobic and anoxic treatment. The
reactor operates similar to a biological
aerated filter, except that the reactor
switches between aerobic to anoxic
conditions during sequential cycling of
the unit. Air, supplied by a blower, is
introduced at the bottom of the filter to
enhance oxygen transfer.
It averaged 59%
removal of TN
effluent of 15 mg/L
over the 13-month
testing period at the
Massachusetts
Alternative Septic
System Test Center
(MASSTC).
$7,500 for unit only. The
manufacturer estimates it
would cost $12,000-
$15,000 for a complete
installation.
Septitech® Model 400 System
Septitech, Inc.
220 Lewiston Road
Gray, ME 04039
http://www.nsf.org/business/water quality
protection center/pdf/SeptiTech VS.pdf
Two-stage fixed film
trickling filter using
a patented highly
permeable
hydrophobic media
Clarified septic tank effluent flows by
gravity into the recirculation chamber
of the SeptiTech unit. A submerged
pump periodically sprays wastewater
onto the attached growth process and
the wastewater percolates through the
patented packing material. Treated
wastewater flows back into the
recirculation chamber to mix with the
contents. Treated water flows into a
clarification chamber and is
periodically discharged to disposal
unit (drainfield, drip irrigation, etc.)
Averaged 64%
removal of TN with
an average TN
effluent of 14 mg/L
over the 12-month
testing period at
MASSTC.
$11,000 for SeptiTech unit
includes shipping and
installation. The
manufacturer estimated that
a total system with pressure
distribution drainfield would
cost approximately $20,000.
-------
Table 6-3. Products that have completed the EPA ETV process for N reduction in domestic wastewater from individual homes, as of May
2005 (continued)
C)
s
System name
Technology
Description of process
Performance
Cost
Bioclere™ Model 16/12
Aquapoint, Inc.
241 Duchanine Blvd.
New Bedford, MA 02745
http://www.nsf.org/business/water quality
protection center/pdf/Bioclere-VS-
SIGNED.pdf
Fixed film trickling
filter.
Septic tank effluent flows by gravity
to the Bioclere clarifier unit from
which it is sprayed or splashed onto
the fixed film media. Treated
effluent and sloughed biomass are
returned to the clarifier unit. A
recirculation pump in the clarifier
periodically returns biomass to the
primary tank. Oxygen is provided to
the fixed film by a fan located on the
top of the unit.
Averaged 57%
removal of TN with
an average TN
effluent of 16 mg/L
over the 13-month
testing period at
MASSTC.
$7,500 for unit itself. Price for
total system would need to
include primary septic tank,
Bioclere unit and disposal
option, with costs in the range
of$12,000-$15,000. The
manufacturer recommends
use in clusters to reduce per
home costs and facilitate
maintenance. Experience with
a 27-home cluster resulted in
costs of $6,800-$8,000 per
home.
Retrofast 0.375 System:
Bio-Microbics
8450 Cole Parkway
Shawnee, KS 66227
http://www.nsf.org/business/water quality
protection center/pdf/Biomicrobics-
FinalVerificationStatement.pdf
Submerged
attached-growth
treatment system,
which is inserted as
a retrofit device into
the outlet side of
new or existing
septic tanks.
The RetroFAST 0.375 System is
inserted into the second
compartment of the septic tank. Air
is supplied to the fixed film
honeycombed media of the unit by
a remote blower. Alternate modes
of operation include recirculation of
nitrified wastewater to the primary
settling chamber for nitrification.
Intermittent use of the blower can
also be programmed to reduce
electricity use and to increase
nitrification.
Averaged 51%
removal of TN with
an average TN
effluent of 19 mg/L
over the 13-month
testing period at
MASSTC.
Product and installation cost
for the Retrofast 0.375
System ranges is estimated to
be $4,000-$5,500 depending
on existing tankage. That cost
includes the FAST unit,
blower, blower housing and
control panel. The local
representative for Bio-
Microbics units believes costs
could be as low as $3,500 for
multiple units.
Recip® RTS-500 System:
Bioconcepts, Inc.
P.O. Box 885
Oriental, NC 28571-0885
http://www.nsf.org/business/water quality
protection center/pdf/Bioconcepts Verifica
tion Statement.pdf
Fixed film filter
This is the newest product to
complete Environmental
Technology Verification (ETV)
Program testing. It is a patented
process developed by the
Tennessee Valley Authority (TVA)
and uses a fixed film filter medium
contained in two adjacent, equally
dimensioned cells. Timers on each
of the two reciprocating pumps
control the process.
Averaged 58%
removal of TN with
an average TN
effluent of 15 mg/L
over the 12-month
testing period at
MASSTC.
Very limited experience with
this single-family unit. The unit
built for ETV testing was a
prototype. The cost per unit,
by itself, is estimated to be
$8,000-$10,000. Cost of the
septic tank and disposal unit
would be extra and the cost
would depend on site
conditions. Conservatively,
cost for a total system could
be $11,000-$15,000.
Source: Adapted from Washington Department of Health 2005
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
5 Wastewater Planning and Treatment System
Management
The previous section describes N-removing individual or cluster wastewater system
technologies, system configurations, and effluent dispersal options. This section describes
management considerations that are essential for optimizing treatment system selection, sizing,
performance, and long-term use, such as inventory systems, wastewater planning, performance
standards, siting and installation guidelines, operation, inspection, maintenance, and residuals
handling. The management tasks described in this section are paramount for reducing nutrient
inputs to the Chesapeake Bay because they establish the framework for selecting and using
specific treatment systems in particular locations. For example, advanced cluster systems are
the best approach for protecting and restoring the Chesapeake Bay when considering
wastewater facilities for new subdivisions and replacing significant numbers of malfunctioning
systems in existing subdivisions.
The following subsections summarize key management program elements viewed as important
for controlling the input of nutrients and other pollutants to the Chesapeake Bay. EPA has
provided extensive guidance, case studies, resources, references, and links on these
management program topics (USEPA 2005, 2010). Specific, detailed information on each topic
below is provided in EPA's (2005) Handbook for Managing Onsite and Clustered (Decentralized)
Wastewater Treatment Systems, available online at
http://cfpub.epa.gov/owm/septic/septic.cfm7page id=289.
5.1 Public Education and Involvement
Decentralized wastewater management programs require public support. The success of such
programs will depend on how well homeowners, system service providers, and other
stakeholders are involved in the development process. Unless people understand the need for a
management program, there is little chance it will be adopted. Once in operation, the program
must keep the community engaged, involved, and informed. Managers should give special
consideration to explaining the need for new requirements for system upgrades, inspections, or
other performance measures.
EPA has partnered with a variety of nonprofit organizations involved in decentralized
wastewater management to improve public education, outreach, and involvement through
development of informational materials, technical products, and training programs. Links to
these partner organizations and the educational, technical, and other resources they provide are
provided at http://cfpub.epa.gov/owm/septic/septic.cfm7page id=260. EPA maintains a
Chapter 6. Decentralized Wastewater Treatment Systems 6-23
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
repository of print, radio, and TV public service announcements and other materials specifically
pertaining to septic system education in its Nonpoint Source Outreach Toolbox, online at
http://www.epa.gov/nps/toolbox/.
5.2 Planning
Planning can be used to integrate management strategies for areas served by both centralized
and decentralized wastewater treatment facilities, serve as the basis for ordinances and
subdivision regulations, and synchronize the community growth plan in harmony with the water
and wastewater infrastructure investments. Integrating wastewater planning functions provides
better long-term management of facilities and can help local officials deal with a number of
needs such as sewer overflows, National Pollutant Discharge Elimination System effluent
limitations, total maximum daily loads (TMDLs), and antidegradation requirements. For
example, integrated planning can minimize problems associated with competition for infiltration
areas between wastewater and stormwater management facilities in new developments, and is
useful in anticipating and preventing adverse water quality effects. Variables to consider during
the planning process include wastewater flows, proximity and uses of nearby water resources,
landscape topography, hydrology, hydrogeology, soils, environmentally sensitive areas,
infrastructure system options and locations, population densities, and need and potential for
clustering treatment or reuse facilities.
EPA supports a wide range of water resource planning and management functions through
programs such as the Clean Water Act section 319 nonpoint source management program, the
Clean Water Act 305(b) assessment reports, TMDLs, wellhead and source water protection
programs, watershed planning initiatives, coastal management, National Estuary Program,
wetlands protection programs, water quality standards, continuous planning processes under
section 303(e), water quality management processes under section 205(j) and 604(b), the Clean
Water State Revolving Fund, and so on. Ideally, the planning and management activities
supporting decentralized wastewater treatment would be integrated, or at least coordinated, with
these and other water resource programs, many of which the states operate.
5.3 Performance Requirements
Performance requirements for systems are necessary to minimize the risks they pose to health
and water resources. Performance requirements specify objectives for each wastewater
management system, which can include physical, chemical, and biological process
components. Performance compliance is based on pollutant-removal estimates for the various
system components (e.g., septic tank, suspended-growth or fixed-film reactors, lagoons,
wetlands, soil, disinfection), verified by periodic field inspections and sampling. Performance
can be measured via numeric or narrative criteria. Numeric criteria reflect time-based, mass
6-24 Chapter 6. Decentralized Wastewater Treatment Systems
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
loadings or pollutant-concentration limits designed to protect sensitive water resources.
Pollutants commonly targeted in performance requirements include nutrients, bacteria, oxygen
demand, and solids.
5.4 Recordkeeping, Inventories, and Reporting
System inventories provide the nuts and bolts for on-site management. Basic system
information—location, type, design capacity, owner, installation, and servicing dates—is
essential to an effective program. The best record-keeping programs feature integrated
electronic databases with field unit data entry (i.e., using a handheld personal digital assistant),
save-to-file computer assisted design drawings, and user-specified reporting formats, and GIS-
based spatial data management and user interface systems.
5.5 Financial Assistance and Funding
Financial assistance might be needed to (1) develop or enhance a management program;
(2) provide support for constructing and modifying wastewater facilities; and (3) support
operation of the program. Funding for program development and operation is often available
from public and private loan or grant sources, supplemented by local matching funds. It can also
be derived from some form of resource sharing among management program partner
organizations such as planning departments or health and water resource agencies. Developing
an RME and financing for constructing and operating facilities require larger investments that
might come from grants and loans or public-private partnerships. Long-term operating costs are
usually borne by system users through payment of fees and assessments.
5.6 Site Evaluation
Evaluating a proposed site in terms of its environmental conditions, physical features, and soil
characteristics provides the information needed to size, select, and locate an appropriate
wastewater treatment system. Regulatory authorities issue installation permits on the basis of
the information collected and analyses performed during the site evaluation. Prescriptive site
evaluation, design, and construction requirements are based on experience with conventional
septic tank/soil dispersal systems and empirical relationships that have evolved over the years.
A soil analysis to a depth of 4 to 6 feet using a hand auger, drill rig, or a backhoe pit, rather than
a simple percolation test, provides a better approach for assessing soils, seasonal water table
fluctuations, and other subsurface site features. Performance-based approaches require a more
comprehensive site evaluation. Site evaluation protocols can include some presently employed
empirical tests, specific soil properties tests and soil pits to characterize soil horizons, mottling,
and a variety of other properties. Modeling groundwater and surface water impacts of multiple
Chapter 6. Decentralized Wastewater Treatment Systems 6-25
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
systems in defined areas (e.g., stream subwatershed) can help to further refine performance
requirements and related system site and design considerations.
5.7 System Design
Decentralized wastewater treatment system design requirements focus on protecting public
health and water resources. However, systems should also be affordable and aesthetically
acceptable. Prescriptive codes that specify standard designs for sites meeting minimum criteria
simplify design reviews, but limit development options and the potential for efficiently meeting
performance requirements. Where management programs rely on the state code for design,
there might not be any need for special review procedures for alternative system designs.
However, in sensitive environments where performance codes are employed, there is a need to
include allowances for alternative designs even if they only expand the number of prescriptive
system choices and site parameters for sites that do not meet the conditions for conventional
systems. Design considerations should address the potential implications of water conservation
fixtures, effects of different pretreatment levels on hydraulic and treatment performance of soil-
based systems, and the O&M requirements of different pretreatment and soil dispersal
technologies.
5.8 Construction/Installation
Poor installation can adversely affect performance of both conventional and advanced systems
that rely on soil dispersion and treatment. Most jurisdictions allow installation or construction to
begin after issuance of a construction permit, which occurs after the design and site evaluation
reports have been reviewed and approved. Performance problems linked to installation/
construction are typically related to soil wetness during construction, operation of heavy
equipment on soil infiltration areas, use of unapproved construction materials (e.g., unwashed
aggregate containing clay or other fines), and overall construction practices (e.g., altering trench
depth, slope, length, location). The effects of improperly installed soil-based systems generally
occur within the first year of operation in the form of wastewater backups. Some improper
construction practices might not be as evident and could take years to manifest themselves in
the form of degraded groundwater or surface water. The regulatory authority or other approved
professionals should conduct inspections at several stages during the system installation
process to ensure compliance with design and regulatory requirements.
6-26 Chapter 6. Decentralized Wastewater Treatment Systems
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
5.9 Operation and Maintenance
O&M is important for all wastewater treatment systems, especially those that rely on
components that are difficult to remedy if damaged—such as a soil dispersal system. Most
system user information includes building awareness of inputs that might affect treatment
processes, such as strong cleaners, lye, acids, biocides, paint wastes, oil and grease, and the
like. Gravity-flow, soil-infiltration systems require little O&M beyond limiting inputs to normal
residential wastes, cleaning effluent screens/filters, and periodic tank pumping (e.g., every 3 to
7 years). Systems employing advanced treatment technologies and electromechanical
components require more intensive O&M attention, e.g., checking switches and pumps,
measuring and managing sludge levels (important for all systems), monitoring and adjusting
treatment process and system timers, checking effluent filters, monitoring effluent quality, and
maintaining disinfection equipment. Operators and service technicians should be trained and
certified for the types of systems they will be servicing; services should be logged and reported
into a management tracking system, such as EPA's TWIST (USEPA 2006), so that long-term
performance can be tracked. The use of a dial-up modem or Internet-based monitoring
equipment can improve operator efficiency and performance tracking when large numbers of
systems are involved.
5.10 Residuals Management
Septic tanks contain settleable solids, fats, oils, grease, and other residuals that require periodic
removal. The primary objective for septage management is to establish procedures for handling
and dispersing the material in a manner that protects public health and water resources and
complies with applicable laws. Approximately 67 percent of the estimated 12.4 billion gallons of
septage produced annually in the United States is hauled to publicly owned treatment works or
other facilities for treatment, while the remaining 33 percent is applied to land. Federal
regulations (under Title 40 of the Code of Federal Regulations Part 503) and state/local codes
strive to minimize exposure of humans, animals, and the environment to chemical contaminants
and pathogens that are often present in septage. Residuals management programs should
include tracking or manifest systems that identify sources, pumpers, transport equipment, final
destination, and treatment or management techniques.
5.11 Training and Certification/Licensing
A variety of professionals and technicians including planners, regulators, designers, installers,
operators, pumpers, and inspectors, are all involved in some aspect of a decentralized
wastewater management program. Training, along with certification or registration, provides
system owners and users with competent service providers and promotes professionalism
among the industry. Service providers need to have a solid working knowledge of treatment
Chapter 6. Decentralized Wastewater Treatment Systems 6-27
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
processes, system components, performance options, O&M requirements, and
laws/regulations. Universities, colleges, technical schools, agency-sponsored training programs,
regional/local workshops, or formal/informal apprenticeship programs can provide such training.
Service providers should have extensive and detailed knowledge of their own service areas and
a general grasp of other related activities (e.g., planning or site evaluation). Service providers
should pursue opportunities for cross-training, joint accreditation/certification, and sharing of
training resources wherever possible.
5.12 Inspections and Monitoring
Perhaps the most significant shortcoming in existing management programs is the lack of
regular inspections and performance monitoring. Area-wide monitoring regimes include testing
groundwater and surface waters for indicators of substandard treatment, such as the presence
of human fecal bacteria and excess nutrients. All systems need to be inspected, at an interval
defined by the technological complexity of system components, the receiving environment, and
the relative risk posed to public health and valued water resources. The best approach is to
establish an inspection regime and schedule on the basis of the system's relative reliance on
electromechanical components combined with health and environmental risk. Less effective
surrogate approaches include, in order of descending effectiveness (1) requiring comprehensive
inspections at regular intervals; (2) third-party inspections at the time of property transfer;
(3) inspections only as part of complaint investigations.
5.13 Corrective Actions and Enforcement
A decentralized wastewater management program should be enforceable to assure compliance
with laws and to protect public health and the environment. Management agencies should have
the legal authority to adopt rules and assure compliance by levying fines, fees, assessments, or
by requiring service providers to respond to system malfunctions. Program administrators
should emphasize those tools that encourage compliance, rather than punishment. It also helps
to have the support of the courts to implement an effective enforcement program. To assure
compliance, management agencies typically need authority to do the following:
• Respond promptly to complaints
• Issue civil and criminal actions or injunctions
• Provide meaningful performance inspections
• Condemn systems or property
• Issue notices of violation (NOVs)
• Correct system malfunctions
6-28 Chapter 6. Decentralized Wastewater Treatment Systems
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
• Implement consent orders and court orders
• Restrict real estate transactions
• Hold formal and informal hearings
• Issue fines and penalties
Chapter 6. Decentralized Wastewater Treatment Systems 6-29
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
6 References
Anderson, D.L. 1998. Natural denitrification in ground water impacted by onsite wastewater
treatment systems. In Proceedings of the 8th National Symposium on Individual and Small
Community Sewage Systems, American Society of Agricultural and Biological Engineers,
Orlando, Florida, March 8-10, 1998, pp. 336-345.
Bedessem, M.E. 2005. Nitrogen removal in laboratory model leachfields with organic-rich
layers. Journal of Environmental Quality 34:936-942.
Behrends, LL, L Houke, P. Jansen, K. Rylant, and C. Shea. 2007. Recip Water Treatment
System with U.V. Disinfection for Decentralized Wastewater Treatment: Part II: Water
Quality Dynamics. In Proceedings of the National Onsite Wastewater Recycling
Association Annual Meeting, Baltimore, MD, March, 2007.
Birgand, F. 2000. Quantification and Modeling ofln-stream Processes in Agricultural Canals of
the Lower Coastal Plain. North Carolina State University, Biological and Agricultural
Engineering Department, Raleigh, NC.
Bushman, J.L. 1996. Transport and Transformations of Nitrogen Compounds in Effluent from
Sand Filter-Septic System Draintile Fields. MS Thesis, Oregon State University.
Bussey, K.W., and D.A. Walter. 1996. Spatial and temporal distribution of specific conductance,
boron, and phosphorus in a sewage-contaminated aquifer near Ashumet Pond, Cape Cod,
Massachusetts. U.S. Geological Survey Open-File Report 96-472, 44 p.
Cheng, F., R. Muftikian, Q. Fernando, and N. Korte. 1997. Reduction of nitrate to ammonia by
zero-valent iron. Chemosphere 35(11):2689-2695.
Cogger, C. 1988. On-site septic systems: The risk of groundwater contamination. Journal of
Envir. Health 51(1):12-16. Sept/Oct, 1988.
Dimick, C.A., K.S. Lowe, R.L. Siegrist, and S.M. Van Cuyk. 2006. Effects of applied wastewater
quality on soil treatment of effluent. In Proceedings of the National Onsite Wastewater
Recycling Association 15th Annual Conference, Denver, CO, August 28-31, 2006.
Etnier, C.D., D. Braun, A. Grenier, A. Macrellis, R.J. Miles, and T.C. White. 2005. Mico-Scale
Evaluation of Phosphorus Management: Alternative Wastewater systems Evaluation.
Project No. WU-HT-03-22. Prepared for the National Decentralized Water Resources
Capacity Development Project, Washington University, St. Louis, MO, by Stone
Environmental, Inc., Montpelier, VT.
6-30 Chapter 6. Decentralized Wastewater Treatment Systems
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
Gold, A.J., J.T. Sims, and G. Loomis. 2002. A risk-based approach to nitrogen contamination
from decentralized wastewater treatment, In Proceedings of Northeast Onsite Wastewater
Treatment Short Course, Newport, Rl, March 24-26, 2002.
Heufelder, G., S. Rask, and C. Burt. 2007 Performance of Innovative Alternative Onsite Septic
Systems for the Removal of Nitrogen in Barnstable County, Massachusetts 1999-2007.
Barnstable County Department of Health and Environment, Barnstable, MA.
Higgins, J., G. Heufelder. S. Foss, J. Costa, and S. Corr. 2002. Advanced onsite wastewater
treatment technology performance. In Proceedings of Northeast Onsite Treatment Short
Course, Newport, Rl, March, 2002.
Hiscock, K.M., J.W. Lloyd, and D.N. Lerner. 1991. Review of natural and artificial denitrification
of groundwater. Water Research (GB) 25(9): 1099-1111.
Integrated Upflow Services, Inc. 2010. Information on Upflow Filter Denitrification Process.
. Accessed April 28, 2010.
Jenssen, P.O., and R.L. Siegrist. 1990. Technology assessment of wastewater treatment by soil
infiltration systems. Water Science Tec/?no/ogy22(3-4):83-92.
Joubert, L, P. Hickey, D.Q. Kellogg, and A.J. Gold. 2003. Wastewater Planning Handbook:
Mapping Onsite Treatment Needs, Pollution Risks, and Management Options. NDWRCDP
Report WU-HT-01-07,. Washington University, St. Louis, MO.
Lee, S., K. Lee, S. Rhee, and J. Park. 2007. Development of a new zero-valent iron zeolite
material to reduce nitrate without ammonium release. Journal of Environmental
Engineering 133(1):6-12.
Lombardo, P., N. Brown, J. Barnes, K. Foreman, and W. Robertson. 2005. Holistic approach for
coastal watershed nitrogen management. In Proceedings of the 2005 National Onsite
Wastewater Recycling Association Annual Meeting Conference Proceedings, Cleveland,
OH, October, 2005.
Lombardo, P. 2006. Phosphorus Geochemistry in Septic Tanks, Soil Absorption Systems, and
Groundwater. Lombardo Associates, Inc., Newton, MA.
Long, T. 1995. Methodology to predict nitrogen loading from on-site sewage treatment systems.
In Proceedings of the Northwest Onsite Wastewater Treatment Short Course, ed,
R.W. Seabloom. University of Washington, Department of Civil Engineering, Seattle,
Washington, September, 1995.
Chapter 6. Decentralized Wastewater Treatment Systems 6-31
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
Nitrabar. 2010. A pan-European EC LIFE Environment Project to demonstrate a passive system
for the removal of nitrates derived from agricultural practices, .
Accessed November 20, 2009.
Noah, M. 2006. Drainfield rehabilitation. Small Flows Quarterly. Winter 2006. West Virginia
University, National Environmental Services Center, Morgantown, WV.
Omni Environmental Systems, Inc. 2010. Information on OMNI denitrification process.
. Accessed November 29, 2009.
Otis, R.J. 2007. Estimates of Nitrogen Loadings to Groundwaterfrom Onsite Wastewater
Treatment Systems in the Wakiva Study Area. Prepared for Florida Department of Health,
Tallahassee, FL.
.
Accessed August, 2009.
NSF International. 2009. Final Evaluation Report, Pennsylvania Onlot Technology Verification
Program, Orenco Systems, Inc. AdvanTex AX20N. Prepared for Pennsylvania Department
of Environmental Protection, by NSF International, Ann Arbor, Ml.
Postma, F.B., A.J. Gold, and G.W. Loomis. 1992. Nutrient and microbial movement from
seasonally used septic systems. Journal of Environmental Health. 55(2):5-10.
Rich, B. 2005. La Pine National Demonstration Project Final Report, 1999-2005. U.S.
Environmental Protection Agency and supported by the Deschutes County, Oregon,
Environmental Health Division, Oregon Department of Environmental Quality, and the U.S.
Geological Survey.
Rich, B, D. Haldeman, T. Cleveland, J. Johnson, R. Weick, and R. Everett. 2003. Innovative
systems in the La Pine National demonstration project. In Proceedings of the Twelfth
Northwest On-Site Wastewater Treatment Short-Course, Seattle, WA, September, 2003.
Robertson, W.D., and J.A. Cherry. 1992. Hydrogeology of an unconfined sand aquifer and its
effect on the behavior of nitrogen from a large-flux septic system. Hydrogeology Journal
1992:32^4.
Robertson, W.D., and J.A. Cherry. 1995. In situ denitrification of septic-system nitrate using
reactive porous media barriers: field trials. Ground H/ater33(1):99-111.
Smith, D.P., R.J. Otis, and M. Flint. 2008. Florida Passive Nitrogen Removal Study. Prepared
for the Florida Department of Health, City, FL.
Stacey, P.E. 2002. Nitrogen effects and management: Implementing the Long Island sound
study. In Proceedings of Northeast Onsite Wastewater Treatment Short Course, Newport,
Rl, March 24-26, 2002.
6-32 Chapter 6. Decentralized Wastewater Treatment Systems
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
Starr, R.C., and R.W. Gillham. 1989. Controls on Denitrification in Shallow Unconfined Aquifers.
In Contaminant Transport in Groundwater, Proceedings of the International Symposium on
Contaminant Transport in Groundwater, Stuttgart, Germany, April, 1989.
Stewart, L.W., and R.B. Reneau Jr. 1984. Septic Tank Disposal Experiments using
Nonconventional Systems in Selected Coastal Plain Soils. Prepared for the Virginia
Department of Health, Richmond, VA, and Virginia Polytechnic Institute and State
University, Blacksburg VA.
Stewart, L.W., and R.B. Reneau Jr. 1988. Shallowly placed, low pressure distribution system to
treat domestic wastewater in solils with fluctuating high water tables. Journal of
Environmental Quality 17(3):499-504.
Stone Environmental. 2005. Risk-Based Approach to Community Wastewater Management:
Tisbury, Massachusetts. Project No. WU-HT-00-26. Prepared for the National
Decentralized Water Resources Capacity Development Project, Washington University,
St. Louis, MO, by Stone Environmental, Inc., Montpelier, VT.
Tetra Tech. 2007. Cost and Performance of Onsite and Clustered Waste water Treatment
Systems (unpublished). Tetra Tech, Inc., Fairfax, VA.
Tyler, E.J., D.L. Mokma, and M. Corry. 2003. Soil hydraulic and treatment performance for
onsite model performance code development. In Proceedings of the Twelfth Northwest
On-Site Wastewater Treatment Short Course, Seattle, WA, September, 2003.
USEPA (U.S. Environmental Protection Agency) and NSF International. 2003. Environmental
Technology Verification Report for Bioclere. EPA-832-F-02-025. U.S. Environmental
Protection Agency, Office of Water, Washington, DC.
USEPA (U.S. Environmental Protection Agency). 1993. Nitrogen Control. EPA/625/R-93/010.
U.S. Environmental Protection Agency, Offices of Research and Development and Water,
Cincinnati, OH.
USEPA (U.S. Environmental Protection Agency). 1998. Permeable Reactive Barrier
Technologies for Contaminant Remediation. U.S. Environmental Protection Agency, Office
of Research and Development, Office of Solid Waste and Emergency Response,
Washington, DC.
USEPA (U.S. Environmental Protection Agency). 1999. Water Efficiency Technology Fact
Sheet—Composting Toilets. U.S. Environmental Protection Agency, Office of Water,
Washington, DC.
USEPA (U.S. Environmental Protection Agency). 2000. Onsite Wastewater Treatment Systems
Technology Fact Sheet 12—Land Treatment Systems. EPA-625-R-00-008. U.S.
Environmental Protection Agency, Office of Research and Development, Washington, DC.
Chapter 6. Decentralized Wastewater Treatment Systems 6-33
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
USEPA (U.S. Environmental Protection Agency). 2002a. Onsite Wastewater Treatment
Systems Manual. EPA-625-R-00-008. U.S. Environmental Protection Agency, Office of
Water, Washington, DC.
USEPA (U.S. Environmental Protection Agency). 2002b. Wastewater Technology Fact Sheet:
The Living Machine. EPA-832-F-02-025. U.S. Environmental Protection Agency, Office of
Water, Washington, DC.
USEPA (U.S. Environmental Protection Agency). 2004. Guidelines for Water Reuse. EPA-625-
R-04-108. U.S. Environmental Protection Agency, Washington, DC.
. Accessed April 27,
2010.
USEPA (U.S. Environmental Protection Agency). 2005. Handbook for Managing Onsite and
Clustered (Decentralized) Wastewater Treatment Systems. EPA 832-B-05-001. U.S.
Environmental Protection Agency, Office of Wastewater Management, Washington, DC.
USEPA (U.S. Environmental Protection Agency). 2006. The Wastewater Information System
Tool (TWIST). EPA 832-E-06-001. U.S. Environmental Protection Agency, Office of
Wastewater Management, Washington, DC.
USEPA (U.S. Environmental Protection Agency). 2007. Wastewater Management Fact Sheet—
Membrane Bioreactors. U.S. Environmental Protection Agency, Office of Water,
Washington, DC. .
Accessed April 29, 2010.
USEPA (U.S. Environmental Protection Agency). 2009. The Next Generation of Tools and
Actions to Restore Water Quality in the Chesapeake Bay, A Revised Report Fulfilling
Section 202a of Executive Order 13508. U.S. Environmental Protection Agency,
Washington, DC.
USEPA (U.S. Environmental Protection Agency). 2010. Individual and Clustered (Decentralized)
Wastewater Management Program Elements. Web Supplement.
. Updated January 2010.
Accessed February 24, 2010.
Valiela, I., G. Collins, J. Kremer, K. Lajitha, M. Geist, B. Seely, J. Brawley, and C.H. Sham.
1997. Nitrogen loading from coastal watersheds to receiving estuaries: New method and
application. Ecol. Appl. 7(2):358-380.
Vallino, J., and K. Foreman. 2008. Effectiveness of Reactive Barriers for Reducing N-Loading to
the Coastal Zone, Submitted to The NOAA/UNH Cooperative Institute for Coastal and
Estuarine Environmental Technology (CICEET). Ecosystems Center Marine Biological
Laboratory Woods Hole, MA.
6-34 Chapter 6. Decentralized Wastewater Treatment Systems
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
Walker, W.G., J. Bouma, D.R. Keeney, and P.G. Olcott. 1973. Nitrogen transformations during
subsurface disposal of septic tank effluent in sands: Ground water quality. Journal of
Environmental Quality 2(4):475^80. Oct-Dec 1973.
Washington State Department of Health. 2005. Nitrogen Reducing Technologies for Onsite
Wastewater Treatment Systems. Prepared for the Puget Sound Action Team, by
Washington Department of Health, Olympia, WA.
. Accessed April 27, 2010.
WERF (Water Environment Research Foundation). 2006. Decentralized Systems for Green
Buildings and Sustainable Sites. WERF Stock No. DEC3R06. December, 2006.
. Accessed April 27, 2010.
WERF (Water Environment Research Foundation). 2010. Distributed Water Infrastructure in
Sustainable Communities: A Guide for Decision-makers. WERF DEC3R06. March 2010.
. Accessed April 27, 2010
WE&T Research Notes. 2009. Method shows promise for removing groundwater nitrate,
researchers say. Water, Environment, and Technology 21(11):6-8.
Chapter 6. Decentralized Wastewater Treatment Systems 6-35
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
Chapter 7.
Hydromodification
Contents
1 Overview 7-3
1.1 Sources 7-4
1.1.1 Streambank and Shoreline Erosion 7-4
1.1.2 Channelization 7-4
1.1.3 Dams and In-Stream Structures 7-5
1.2 Contribution to Nonpoint Source Pollution in Chesapeake Bay 7-6
2 Chesapeake Bay Hydromodification Implementation Measures 7-8
2.1 General Principles and Goals 7-8
2.2 Implementation Measures 7-9
2.2.1 Implementation Measure H-1: Protect Streambanks and Shorelines from
Erosion 7-10
2.2.2 Implementation Measure H-2: Control Upland Sources of Sediment and
Nutrients at Dams 7-12
2.2.3 Implementation Measure H-3: Restore In-Stream and Riparian Habitat
Function 7-14
2.2.4 Implementation Measure H-4: Reduce Pollutant Sources through
Operational and Design Management 7-15
2.2.5 Implementation Measure H-5: Restore Stream and Shoreline Physical
Characteristics 7-17
3 Chesapeake Bay Hydromodification Practices 7-20
3.1 Existing Practices 7-20
3.2 Updated and Next Generation Practices 7-21
3.2.1 Advanced Hydroelectric Turbines 7-22
3.2.2 Bank Shaping and Planting 7-23
3.2.3 Brush Mattressing 7-24
3.2.4 Cross Vanes 7-26
Chapter 7. Hydromodification 7-1
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
3.2.5 Establish and Protect Stream Buffers 7-28
3.2.6 Flow Augmentation 7-32
3.2.7 Joint Planting 7-35
3.2.8 Legacy Effects of Dams and Dam Removal 7-37
3.2.9 Live Crib Walls 7-41
3.2.10 Live Fascines 7-43
3.2.11 Live Staking 7-46
3.2.12 Log and Rock Check Dams 7-49
3.2.13 Marsh Creation and Restoration 7-51
3.2.14 Multi-Cell Culvert 7-53
3.2.15 Natural Channel Design and Restoration 7-55
3.2.16 Non-Eroding Roadways 7-60
3.2.17 Revetments 7-64
3.2.18 Riparian Improvements 7-66
3.2.19 Riprap 7-68
3.2.20 Rock and Log Vanes 7-69
3.2.21 Selective Withdrawal 7-71
3.2.22 Shoreline Sensitivity Assessment 7-72
3.2.23 Step Pools 7-73
3.2.24 Streambank Dewatering 7-75
3.2.25 Toe Protection 7-77
3.2.26 Turbine Operation 7-78
3.2.27 Turbine Venting 7-79
3.2.28 Vegetated Buffers 7-80
3.2.29 Vegetated Filter Strips 7-82
3.2.30 Vegetated Gabions 7-84
3.2.31 Vegetated Geogrids 7-85
3.2.32 Vegetated Reinforced Soil Slope (VRSS) 7-86
3.2.33 Weirs 7-87
3.2.34 Wing Deflectors 7-89
4 References 7-92
7-2 Chapter 7. Hydromodification
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
1 Overview
The Chesapeake Bay and its tributaries, representing the nation's largest estuary, is a resource
of important economic, social and environmental significance. The Chesapeake Bay ecosystem,
however, remains severely degraded primarily because of pollution from excess nitrogen (N),
phosphorus (P), and sediment, which enters surface waters. Those pollutants come from
multiple diverse sources within the Chesapeake Bay watershed, but the primary sources are
agriculture, urban and suburban runoff, wastewater, and airborne contaminants (Chesapeake
Bay Program 2009). Another contributor of pollutants to the Chesapeake Bay is
hydromodification. The states in the U.S. Environmental Protection Agency's (EPA's) Region 3
report in their biennial water quality report that a cumulative total of 1,427 miles of assessed
rivers and streams, 1,687 acres of assessed lakes and reservoirs, and 1,916 square miles of
assessed bays and estuaries in the Mid-Atlantic are impaired by hydromodification.
The term hydromodification as used in this guidance refers to the alteration of the hydrologic
characteristics of waterbodies, which in turn could cause degradation of water resources. Many
activities that are considered forms of hydromodification have been conducted and continue to
be conducted because they are considered to be critical to human activities, such as dredging
shipping channels for commerce or constructing culverts at stream crossings for transportation.
Hydromodification can also refer to activities that are conducted in and adjacent to stream
channels to maintain stream functions or reduce damage to streams or adjacent properties such
as clearing of debris or armoring of streambanks.
While hydromodification activities likely occurred within the Chesapeake Bay watershed before
European settlement (e.g., fish traps, secondary effects from riparian agriculture) the scale and
scope of hydromodification increased dramatically with the advent of European expansion on
the east coast of North America. Early settlers constructed dams to harness hydropower and
drained floodplain areas for farming (Walter and Merritts 2008; Schenk and Hupp 2009). As
development accelerated through the colonial, post revolutionary and industrial periods
hydromodification activities expanded to include dredging of natural and man-made waterways
for commerce, construction of water supply, recreational and flood control dams, and channel
straightening and dredging for flood control and agriculture. In more recent years, development
of the built environment has resulted in secondary channel erosion within and downstream of
urban centers.
Chapter 7. Hydromodification 7-3
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
1.1 Sources
Hydro modification activities are grouped into three general categories for the purposes of this
chapter: (1) channelization and channel modification, (2) dams, and (3) streambank and
shoreline erosion. Such broad categories are useful in that they provide a logical organization
for hydromodification activities. However, as is described later in this chapter, implementation
measures and practices can apply across these three activity categories. In addition certain
hydromodification activities might not fit neatly within any of the three categories.
1.1.1 Streambank and Shoreline Erosion
Streambank and shoreline erosion refers to the degradation of stream, estuary and lake shore
areas resulting in loss of soil and other material landward of the bank along non-tidal streams
and rivers. Streambank erosion occurs when the sediment on streambanks detaches and
becomes mobilized within or near the stream channel. Detachment is a complex process
resulting from the interaction of streamflow, vegetation, cohesive properties of soil and the soil
water interface. Eroded material is often carried downstream and re-deposited in the channel
bottom or in point bars located along bends in the waterway. Shoreline erosion occurs in large
open waterbodies, such as larger lakes and the lower estuarine portion of the Chesapeake Bay,
where waves and currents sort coarser sands and gravel from eroded banks and move them in
both directions along the shore away from the area being eroded. While the underlying forces
causing the erosion could be different for streambank and shoreline erosion, the results, erosion
and its impacts, are usually similar. It is also important to note that streambank and shoreline
erosion are natural processes and that natural background levels of erosion also exist and might
be necessary to ensure the health of a particular stream. However, human activities along or
adjacent to streambanks or shorelines can accelerate erosion and other nonpoint sources of
pollution.
In both urban and rural areas, streambank erosion is often associated with changing land use
characteristics within a watershed such as increased impervious surfaces. Because the erosion
of streambanks and shorelines is often closely related to upland activities which occur outside of
riparian areas, it is often necessary to consider solutions to these issues as a component of
overall watershed protection and restoration objectives. The topic of upland effects on stream
channels is covered in more detail in the Urban chapter of this guidance.
1.1.2 Channelization
Channelization and channel modification include activities such as straightening, widening,
deepening, and clearing channels of debris and accumulated sediment. Objectives of
channelization and channel modification projects include flood control, infrastructure protection,
7-4 Chapter 7. Hydromodification
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
channel and bank stabilization, habitat improvement/enhancement, recreation, and flow control
for water supply (source). Channelization activities play an important role in nonpoint source
pollution in the Chesapeake Bay by affecting the timing and delivery of pollutants that enter the
water. Channelization can also be a cause of higher flows during storm events, which increases
the risk of flooding.
Historically, channelization occurred to reduce flooding, drain wet areas for agriculture and to
allow for commerce among, other reasons. In recent years however regulatory requirements
primarily driven by the Clean Water Act have limited traditional hydromodification activities
within stream channels and waterbodies. Simultaneously, water resource managers have
recognized the critical role that healthy stable stream corridors play in the protection and
improvement of water quality and living resources within the Chesapeake Bay. As a result many
of the hydromodification activities occurring currently are those related to maintenance and
restoration of channel corridors and shorelines.
1.1.3 Dams and In-Stream Structures
Dams and in-stream structures are artificial barriers on waterbodies that control the flow of
water. These structures can be built for a variety of purposes, including flood control, power
generation, irrigation, navigation, and to create ponds, lakes and reservoirs for uses such as
municipal water supply, fish farming and recreation. While these types of structures are
constructed to provide benefits to society, they can contribute to nonpoint source pollution and
have detrimental effects on living resources. For example dams can alter flows that ultimately
can cause effects on water quality and roadway culverts can result in the scour of stream
sediments at their outlet. While these structures were often built for purposes related to human
needs in many cases that need is no longer present (e.g., small hydropower dams to support
manufacturing). As a result water resource managers have conducted detailed cost benefit
analysis at many dams and the result often show that the benefits of dam removal outweigh the
benefits of continuing to maintain and operate the dam.
An important development in the effect of dams in water quality is the increasing trend of dam
removal within the Chesapeake Bay. As dams reach their life expectancy many will be removed
for safety concerns or to restore the connectivity of aquatic ecosystems. This phenomenon is
covered extensively in one of the practices (Legacy effects of Dams and Dam Removal)
recommended in Section 3 of this chapter.
Chapter 7. Hydromodification 7-5
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
1.2 Contribution to Nonpoint Source Pollution in
Chesapeake Bay
The contribution of hydromodification activities to sediments and nutrient loads to the
Chesapeake Bay is poorly defined in the current research literature. Traditionally, land use
managers and water resources professionals categorized nonpoint source pollutant loadings
based on specific land uses (such as agricultural, urban and silviculture). Contribution of specific
hydromodification activities such as channel erosion or dams was less well defined. With recent
research on the topic, however, increased attention and research activity has been focused on
separating the contribution of specific activities such as stream corridor instability to the overall
pollutant loading to the Bay.
The interaction between pollutants from upland sources and those which originate within the
stream corridor is a complex relationship in which in-stream transported pollutants are often
affected by historic or current upland activities. During the 1700s and 1800s eroding upland
agricultural areas resulted in significant sediment storage within stream corridors typically called
legacy sediment (USGS 2003). The construction of mill dams during that period resulted in the
impoundment and storage of sediment behind tens of thousands of mill dams in the mid-Atlantic
region. Subsequent removal of these dams during the late industrial period and urban and
suburban development in the past 100 years has led to remobilization of the legacy sediments
as stream corridors have become instable and streambanks have eroded (USGS 2003).
Because of the intimate nature of hydromodification activities with the stream corridor, there is
understandably a close relationship between those activities and sediment delivery to surface
waters. A summary of existing information of the impacts of stream hydromodification on the
quality of the Chesapeake Bay is provided in Table 7-1. These studies demonstrate the
importance of stream restoration and protection in achieving pollutant reduction in the
Chesapeake Bay, particularly for sediment and the P that accompanies sediment loading.
While the contribution of sediment from streambank erosion might be a significant source in
many streams, the percentage of unstable streams within the Chesapeake Bay watershed is
unknown (USGS 2003).
The contribution of hydromodification to other pollutants of concern in the Chesapeake Bay is
even less well documented. N contribution throughout the watershed is primarily from
agricultural, wastewater, and airborne sources. N in its most commonly observed forms is
present in very low levels within contributions from hydromodification sources. P on the other
hand, given its tendency to become soil and particulate bound, is often present in the legacy
sediments, which are significant contributors to eroding streams.
7-6 Chapter 7. Hydromodification
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
Table 7-1. Studies quantifying the impact of sediment loading from stream hydromodification on
Chesapeake Bay water quality
Study
A Summary Report of Sediment Processes in
Chesapeake Bay and Watershed, USGS, Water-
Resources Investigations Report 03-4123, 2003
Schueleret.al. 2000. The Practice of Watershed
Protection, Technical Note #119 from Watershed
Protection Techniques 3(3):729-734, Center for
Watershed Protection, 2000.
U.S. Environmental Protection Agency. 2001 .
Protecting and Restoring America's Watersheds:
Status, Trends, and Initiatives in Watershed
Management, EPA 840-R-00-001 .
http://www.epa.qov/owow/nps/urbanm/pdf/urban
guidance.pdf.
Gellis et al. Synthesis of U.S. Geological Survey
Science for the Chesapeake Bay Ecosystem and
Implications for Environmental Management,
Chapter 6: Sources and Transport of Sediment in
the Watershed. 2007, U.S. Geological Survey
Circular 131 6.
Gellis et al. 2009, Sources, transport, and storage
of sediment in the Chesapeake Bay Watershed:
U.S. Geological Survey Scientific Investigations
Report 2008-5 186
Devereux et al. Suspended-sediment sources in
an urban watershed, Northeast Branch Anacostia
River, Maryland. Hydrological Processes,
Accepted 2009.
Findings
Summarizes the impacts and sources of sediment
and notes that sediment yield from urbanized areas
can remain high after active construction is
complete because of increased stream corridor
erosion due to altered hydrology
Stream enlargement, and the resulting transport of
excess sediment, is caused by urban development
Straightened and channelized streams carry more
sediments and other pollutants to their receiving
waters. Up to 75% of the transported sediment from
the Pocomoke watershed on the Eastern Shore of
Maryland was found to be erosion from within the
stream corridor
Sediment sources are throughout the Chesapeake
Bay watershed, with more in developed and steep
areas
In the Piedmont region, streambank erosion was a
major source of sediment in developed Little
Conestoga Creek; 30% of sediment from the
Mattawoman Watershed on the Coastal Plain (flat
land) is from streambanks
Streambank erosion was the primary source of
sediment in the Northeast Branch Anacostia River
Chapter 7. Hydromodification
7-7
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
2 Chesapeake Bay Hydromodification
Implementation Measures
In 2007 EPA published a guidance document titled National Management Measures to Control
Non-point Source Pollution from Hydromodification whose purpose was to provide background
information on nonpoint source pollution and to offer a variety of solutions for reducing nonpoint
source pollution resulting from hydromodification. Background information included a discussion
of the sources of nonpoint source pollution and mechanisms for transport into the nation's
waters. The guidance further presented a series of Management Measures for use on a national
scale to directly address the causative factors for nonpoint source pollution. Management
measures as presented in the 2007 document establish performance expectations and where
appropriate specific actions that can be taken to prevent or minimize nonpoint source pollution.
A series of practices was also described for each management measure. Practices are specific
actions taken to achieve, or help achieve a management measure. Practices are often termed
best management practices (BMPs); however, the word best was dropped from the 2007
Hydromodification guidance and will not be used in this chapter because the use of the
adjective is too subjective.
This chapter expands on the extensive resources provided in the 2007 document while focusing
on the pollutants, sources, and practices considered important to the overall goal of restoring
the health of the Chesapeake Bay. Implementation measures (formerly management measures)
presented are either the same or improved versions of those presented in the 2007 guidance.
Where available, information on the application, design, and performance of specific practices
suitable for use in the Chesapeake Bay are provided. To support one of the key steps required
by the Executive Order 13508 to define next generation tools, a number of practices have been
added to this chapter, which exhibit proven capability to address the nonpoint source issues
within the Chesapeake Bay. This chapter and the 2007 guidance are intended to be used in
tandem to provide the reader with an updated summary of tools and techniques appropriate for
addressing nonpoint source pollution in the Chesapeake Bay.
2.1 General Principles and Goals
The purpose of this chapter is to provide the user with background information on how
hydromodification activities affect nutrient and sediment impacts within the Chesapeake Bay
and to provide guidance on a range of practices that can be implemented to reduce the impact
of hydromodification activities on Bay water quality. While this chapter focuses on practices that
are relevant to the Chesapeake Bay and its associated watershed specifically, the information
7-8 Chapter 7. Hydromodification
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
provided herein is also widely relevant wherever hydromodification activities result in
degradation of surface waters.
While the primary focus of this chapter is on reducing loading of sediment, N, and P, it is
important to note that there are often numerous secondary benefits to each specific practice
detailed herein. To that end appropriate additional information is provided on secondary benefits
such as those associated with living resources (and complementing the activities suggested in
draft report 202(g) of Executive Order 13508). For example bioengineering techniques such as
live staking and brush mattressing are typically applied to an eroding streambank principally to
reduce sediment loading to the associated stream. However, the function of those practices is
based on establishing riparian vegetation, which is an important component in improving aquatic
riparian habitat.
For many hydromodification activities and their associated effects, a close relationship exists to
other chapters of this guidance. In such cases, the reader might be directed to the respective
section for additional guidance. For instance, increased rate and volume of stormwater runoff
from urbanizing areas often leads to channel and streambank erosion. In that case, the
causative factor of the effect (urbanization) is covered in the urban section of this chapter.
Because streambank erosion is itself considered a form of hydromodification, the effect is
described in detail and number of structural practices recommended to address the effect within
the stream corridor.
While this chapter recommends a series of approaches and information on specific tools and
techniques to address nonpoint source pollution in the Chesapeake Bay watershed on a project
basis, each project must be considered within the context of the watershed or subwatershed in
which it is prescribed. The successful implementation of watershed restoration requires that
projects be identified and selected consistent with watershed assessments and prioritized
according to the overall watershed restoration goals (Beechie et al. 2008). Furthermore,
individual projects should be considered as a component of watershed restoration and
measured according to the cumulative benefits of other similar watershed restoration projects
that might be proposed (Kondolf et al. 2008).
2.2 Implementation Measures
To accomplish the goals set forth above, this chapter suggests a series of implementation
measures that are recommended to address the effects of hydromodification. The reader might
notice that the 2007 guidance document includes six Management Measures that tribal, state,
or local programs could implement to address nonpoint source pollution from hydromodification
activities. In this chapter, the six management measures have been reduced to five categories
and renamed implementation measures. That terminology is used in this chapter because they
Chapter 7. Hydromodification 7-9
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
are measures that can be implemented to address specific functional causes of impacts of
hydromodification activities.
Implementation Measures:
H-l. Protect Streambanks and Shorelines from Erosion
H-2. Control Upland Sources of Sediment and Nutrients at Dams
H-3. Restore In-stream and Riparian Habitat Function
H-4. Reduce Pollutant Sources through Operational and Design Management
H-5. Restore Stream and Shoreline Physical Characteristics
2.2.1 Implementation Measure H-1: Protect Streambanks and
Shorelines from Erosion
Implementation Measure H-1:
The protection of Streambanks and shorelines from erosion refers to the installation
of structural or biological practices at or near the land water interface. The primary
goals of this implementation measure are the following:
1. Protect streambank and shoreline features with the potential to reduce
nonpoint source pollution
2. Protect Streambanks and shorelines from erosion from uses of either the
shorelands or adjacent surface waters
Implementation Measure H-1 focuses on preserving stable Streambanks and shorelines to limit
the loss of pollutants, most notably sediment, from the erosion at the land water interface. This
measure is most closely related with Management Measure 6 of the 2007 guidance (Eroding
Streambanks and Shorelines). Practices appropriate for addressing Implementation Measure
H-1 consist of both structural practices such as riprap as well as management practices such as
non-eroding roadways. Where possible, the practitioner should consider the protection of
Streambanks and shoreline within the context of overall watershed goals and select practices
that address multiple watershed objectives were possible.
7-10 Chapter 7. Hydromodification
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
The application of bioengineering stream armoring techniques, which use vegetation and
natural systems, to address erosion for instance should be considered before implementing
more rigid, structural controls such as riprap. While bioengineering techniques might not be
suitable for all applications, they often support the objectives of other implementation measures
and overall watershed goals.
Practices
The practices noted in Table 7-2 are suggested as appropriate to address Implementation
Measure H-1 and are described in more detail in Section 3 of this chapter. The table categorizes
practices according to whether they were detailed in the previous guidance, updated within this
chapter, or identified as a next generation tool or technique for addressing nonpoint source
pollution in Chesapeake Bay. Updated practices are those that are described in detail in the
2007 guidance but have updated or region-specific information in Section 3. Next generation
tools and techniques are those newer practices that had not been previously identified as
appropriate for addressing Implementation Measure H-1 but are described in detail in Section 3.
Table 7-2. Practices appropriate for use in addressing Implementation Measure H-1
Practice
Breakwaters
Bulk Heads and Seawalls
Groins
Multi-Cell Culverts
Non-Eroding Roadways
Return Walls
Rip Rap
Toe Protection
Described in
2007 guidance?
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Updated?
Yes
Yes
Yes
Next generation
tools and
techniques?
Yes
Page
7-53
7-60
7-68
7-77
Note: Clicking this link will access the 2007 document (National Management Measures to Control Non-point Source
Pollution from Hvdromodification). To find a specific practice, use the bookmarks.
Chapter 7. Hydromodification
7-11
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
2.2.2 Implementation Measure H-2: Control Upland Sources of
Sediment and Nutrients at Dams
Implementation Measure H-2:
The control of upland sources of nonpoint source pollutants at dams and other
hydromodification facilities, refers to the active implementation of pollutant control
techniques and practices that minimize the source generation and reduce the
transport of sediments and nutrients into the Chesapeake Bay and its watershed. This
implementation measure is well described in the 2007 guidance document (formerly
titled Erosion and Sediment Control for Construction of New Dams and Maintenance of
Existing Dams). The goals of this implementation measure are
1. Reduce the generation of sediment and nutrients during and after construction
2. Retain eroded sediment and nutrients on-site
3. Apply nutrients at rates necessary to establish and maintain vegetation
without causing significant nutrient runoff to surface waters
Implementation Measure H-2 is identical to Management Measure 3 from the 2007
hydromodification guidance. No updated information is provided on this measure whose
purpose is to prevent sediment and nutrients from entering surface waters during the
construction or maintenance of dams. Because of the extensive environmental permitting
necessary for the construction of dams in the Chesapeake Bay watershed and the developed
nature of the region's water resources, it is unlikely that significant dam construction will occur in
the near future. Maintenance of existing dams and impoundments, therefore, is likely to be the
most significant activity to which this measure is applicable.
No updated design or performance information is available for the practices recommended for
this implementation measure. As a result, for more information on specific practices, see the
2007 hydromodification guidance.
Practices
The practices noted in Table 7-3 are suggested as appropriate to address Implementation
Measure H-2.
7-12 Chapter 7. Hydromodification
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
Table 7-3. Practices appropriate to addressing Implementation Measure H-2
Practice
Check Dams
Coconut Fiber Roll
Construction Runoff Intercepts
Construction Management
Erosion Control Blankets
Locate Potential Land Disturbing Activities away from Critical Areas
Mulching
Preserve Onsite Vegetation
Phase Construction
Retaining Walls
Re vegetate
Project Scheduling
Sediment Basin/Rock Dams
Sediment Fences
Sediment Traps
Seeding
Site Fingerprinting
Sodding
Soil Protection
Surface Roughening
Training ESC
Wildflower Cover
Note: Clicking this link will access the 2007 document (National Management Measures to
Control Non-point Source Pollution from Hvdromodification). To find a specific practice, use the
bookmarks.
Chapter 7. Hydromodification
7-13
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
2.2.3 Implementation Measure H-3: Restore In-Stream and Riparian
Habitat Function
Implementation Measure H-3:
The restoration of in-stream and riparian habitat function refers to the direct
implementation of practices that address functions of the aquatic environment.
Because the practices recommended as part of this implementation measure often do
not address the causative factors behind habitat degradation, other implementation
measures described in this chapter should be considered for implementation. This
implementation measure is well described in the 2007 guidance document (titled
Protection of Surface Water Quality and In-stream and Riparian Habitat). The primary
goal of this implementation measure is
1. Provide for safe passage of fish and other aquatic species upstream or
downstream of dams and other structures
Physical structures that block or impede fish migrations to historic spawning habitats have been
identified as potentially the most important factor in the decline in migratory fish such as
American shad, river herring and the American eel. The removal of blockages or the installation
of structures that encourage or enable fish passage such as fish lifts, fish ladders, and other
passageways are important measures that can be implemented within the Chesapeake Bay to
ensure that migratory fish are able to move freely throughout historical migratory routes.
Approximately 1,924 miles of stream in the Chesapeake Bay watershed have been opened to
fish passage, and Executive Order 13508 states that an additional 1,000 stream miles will be
opened by implementing 100 priority dam-removal, fish-passage projects by 2025.
The restoration of in-stream and riparian habitat function is closely related to Implementation
Measure H-5, Restore Stream and Shoreline Physical Characteristics, described below. The
practices recommended for use to address Implementation Measure H-5 often directly support
the primary goal of this implementation measure. EPA encourages practitioners to consider
these two implementation measures and their respective practices as collaborative techniques
to address nonpoint source pollution in the Chesapeake Bay and its effect on living resources.
Practices
The practices noted in Table 7-4 are suggested as appropriate to address Implementation
Measure H-3 and are described in more detail in Section 3 of this chapter. The table categorizes
practices according to whether they were detailed in the previous guidance, updated within this
chapter, or identified as a next generation tool or technique for addressing nonpoint source
pollution in Chesapeake Bay. Updated practices are those that are described in detail in the
7-14 Chapter 7. Hydromodification
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
2007 guidance but have updated or region-specific information in Section 3. Next generation
tools and techniques are those newer practices that had not been previously identified as
appropriate for addressing Implementation Measure H-3 but are described in detail in Section 3.
Table 7-4. Practices recommended to address Implementation Measure H-3
Practice
Behavioral Barriers
Collection Systems
Establish and Protect
Stream Buffers
Fish Ladders
Fish Lifts
Legacy Effects of Dams
and Dam Removal
Physical Barriers
Riparian Improvements
Shoreline Sensitivity
Assessment
Transfer of Fish Runs
Vegetated Buffers
Vegetated Filter Strips
Described in
2007 guidance?
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Updated?
Yes
Yes
Yes
Yes
Yes
Next generation
tools and
techniques?
Yes
Page
7-28
7-37
7-66
7-72
7-80
7-82
Note: Clicking this link will access the 2007 document (National Management Measures to Control Non-point Source
Pollution from Hvdromodification). To find a specific practice, use the bookmarks.
2.2.4 Implementation Measure H-4: Reduce Pollutant Sources
through Operational and Design Management
Implementation Measure H-4:
Reduction of pollutant sources through operational and design management of dams
refers to the design and management of dams so as to minimize the source generation
and reduce the transport of sediments and nutrients into the Chesapeake Bay and its
watershed. This implementation measure is well described in the 2007 guidance
document (formerly titled Erosion and Sediment Control for Construction of New Dams
and Maintenance of Existing Dams). The goals of this implementation measure are
1. Reduce pollutant generation and impact on living resources through
programmatic dam management
2. Design structures to limit pollutant generation
Chapter 7. Hydromodification
7-15
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
Implementation Measure H-4 addresses pollutants resulting from operational activities at in-
stream facilities such as dams and impoundments. The operation and management of such
facilities typically has minimal impact on the delivery of nonpoint source pollutants to
downstream waters. One notable exception is the removal of a impoundments which is covered
in detail in Implementation Measure H-5 and in the practice: Legacy Effects of Dams and Dam
Removal.
Operational practices do have significant implications on the living resources within and
downstream of structures via their effect on other water quality parameters such as water
temperature and dissolved oxygen. Management should focus on tools and techniques to
reduce the impact of Dam and in-stream structure operation on water quality through the
management of physical flow processes to meet environmental criteria (Olden and Naimen
2010; Merrittetal. 2010).
Practices
The practices noted in Table 7-5 are suggested as appropriate to address Implementation
Measure H-4 and are described in more detail in Section 3 of this chapter. The table categorizes
practices according to whether they were detailed in the previous guidance, updated within this
chapter, or identified as a next generation tool or technique for addressing nonpoint source
pollution in Chesapeake Bay. Updated practices are those that are described in detail in the
2007 guidance but have updated or region-specific information in Section 3. Next generation
tools and techniques are those newer practices that had not been previously identified as
appropriate for addressing Implementation Measure H-4 but are described in detail in Section 3.
Table 7-5. Practices recommended as appropriate to address Implementation Measure H-4
Practice
Advanced Hydroelectric
Turbines
Flow Augmentation
Selective Withdrawal
Turbine Operation
Turbine Venting
Described in
2007 guidance?
Yes
Yes
Yes
Yes
Yes
Updated?
Yes
Yes
Yes
Yes
Yes
Next generation
tools and
techniques?
Page
7-22
7-32
7-71
7-78
7-79
7-16
Chapter 7. Hydromodification
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
2.2.5 Implementation Measure H-5: Restore Stream and Shoreline
Physical Characteristics
Implementation Measure H-5:
The restoration of stream and shoreline physical characteristics is important to
restoring predevelopment hydrology and reducing loading from larger and scouring
flows. Degraded streams can themselves become a source of downstream pollution,
such as when P-laden sediments are mobilized during high-flow events. In such
cases, stream restoration can be a useful strategy to improve downstream water
quality. However, it is important to keep in mind that the elevated flows causing
sediment mobilization must also be addressed (see the Urban and Suburban
chapter). Stream stabilization requires restoration of the stream's energy signature.
The predevelopment hydrology of the watershed must be restored to regain the
predevelopment character of the stream; however, in existing urban areas, that might
be a longer-term goal. The primary goal of this implementation measure is to
1. Restore stable relationship between watershed hydrology and stream and
shoreline geometry. Where streambank or shoreline erosion is a nonpoint
source pollution problem, streambanks and shorelines should be stabilized.
Vegetative methods are strongly preferred unless structural methods are more
effective, considering the severity of stream flow discharge, wave and wind
erosion, offshore bathymetry, and the potential adverse effect on other
streambanks, shorelines, and offshore areas.
Many methods have been developed to restore the physical characteristics of streams and
shorelines to address lost function and instability. While many of the techniques can be applied
in isolation to address specific physical characteristics, for instance installing root wad
revetments to address bank erosion, EPA encourages practitioners to consider the practices
listed below and detailed in Section 3 as components of an overall restoration strategy. It is
important to note that restoration strategies should consider leveraging the natural
characteristics of the stream and shoreline hydrology, geometry, and ecology to address
physical function, such as biological engineering techniques, such as live fascines and brush
layering in preference to techniques that rely on structural characteristics such as revetments.
Where possible, measures should focus on the restoration of physical characteristics that are
appropriate to overall watershed goals and future conditions.
Physical restoration can help to restore the natural ecosystem function of nutrient removal that
occurs in streams. Studies that evaluate the N-removal ability of restored streams are
summarized in Table 7-6.
Chapter 7. Hydromodification 7-17
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
Table 7-6. Studies evaluating the N removal ability of restored streams in the Chesapeake Bay
watershed
Study
Finding
Kaushal et al. 2008. Effects of Stream Restoration
on Denitrification in an Urbanizing Watershed.
Ecological Applications 18(3):789-804.
Streams with ecological functions intact remove N
at a much higher rate than degraded urban
streams, and stream restoration practices can
restore this N removal function
Klocker et al. Nitrogen uptake and denitrification in
restored and unrestored streams in urban
Maryland, USA. Aquatic Sciences, Accepted
October 2009.
Degraded urban streams, deeply eroded and
disconnected from their floodplain have
substantially lower rates of N removal that than
streams hydraulically connected to their riparian
banks via low slopes, and reconnecting the stream
to the floodplain can increase
In addition to the water quality improvements that can be achieved through stream restoration,
the flood management community has become increasingly aware of the benefits of restoration
in preventing flood damages. The Association of State Floodplain Managers (ASFPM) has
prepared a white paper called Natural and Beneficial Floodplain Functions: Floodplain
Management—More than Flood Loss Reduction (http://www.floods.org), which emphasizes the
multiple benefits of protecting and restoring streams and their associated floodplains.
Techniques for stream and floodplain restoration are also described in the Riparian Section of
this guidance chapter. Example references for stream restoration, and for information on the
impacts of urban runoff on stream ecosystems, are provided in Table 7-7.
Table 7-7. References on urban stormwater effects on streams with emphasis on restoration and
habitat
USDA Natural Resources Conservation Service, Part 654 Stream Restoration Design National
Engineering Handbook, 210-VI-NEH, August 2007
Federal Interagency Stream Restoration Working Group (FISRWG) (1998J. Stream Corridor
Restoration: Principles, Processes, and Practices, ISBN-0-934213-60-7, Distributed by the National
Technical Information Service at 1-800-533-6847.
Infiltration vs. Surface Water Discharge: Guidance for Stormwater Managers, Final Report. 03-SW-4,
Water Environment Research Federation (WERF 2006) Appendix B. Assessment of Existing
Watershed Conditions: Effects on Habitat.
Practices
The practices noted in Table 7-8 are suggested as appropriate to address Implementation
Measure H-5 and are described in more detail in Section 3 of this chapter. The table categorizes
practices according to whether they were detailed in the previous guidance, updated within this
chapter, or identified as a next generation tool or technique for addressing nonpoint source
pollution in the Chesapeake Bay. Updated practices are those that are described in detail in the
7-18
Chapter 7. Hydromodification
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
2007 guidance but have updated or region-specific information in Section 3. Next generation
tools and techniques are those newer practices that had not previously been identified as
appropriate for addressing Implementation Measure H-5 but are described in detail in Section 3.
Table 7-8. Practices recommended for addressing Implementation Measure H-5
Practice
Bank Shaping and Planting
Branch Packing
Brush Layering
Brush Mattressing
Cross Vanes
Dormant Post Planting
Joint Planting
Legacy Effects of Dams
and Dam Removal
Live Crib Walls
Live Fascines
Live Staking
Check Dams (Log & Rock)
Marsh Creation and
Restoration
Natural Channel Design
and Restoration
Revetements
Rock and Log Vanes
Root Wad Revetements
Step Pools
Streambank Dewatering
Tree Revetements
Vegetated Gabions
Vegetated Geogrids
Vegetated Reinforced Soil
Slope (VRSS)
Weirs
Wing Deflectors
Described in
2007 guidance?
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Updated?
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Next generation
tools and
techniques?
Yes
Yes
Yes*
Yes
Yes
Yes
Page
7-23
7-24
7-26
7-35
7-37
7-41
7-43
7-46
7-51
7-55
7-64
7-69
7-73
7-75
7-84
7-85
7-86
7-87
7-89
Note: Clicking this link will access the 2007 document (National Management Measures to Control Non-point Source
Pollution from Hvdromodification). To find a specific practice, use the bookmarks.
* This practice was originally named Rosgen's Stream Classification Method in the 2007 guidance document.
Chapter 7. Hydromodification
7-19
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
3 Chesapeake Bay Hydromodification Practices
The practices detailed in this section are suggested as appropriate for use in the Chesapeake
Bay and nationally to address causative factors and impacts of hydromodification. While many
of these practices were previously described in detail in the 2007 guidance document, some are
new and represent the next generation of tools and actions to address nonpoint source
pollution. For those practices described in the 2007 guidance and for which no additional
information is relevant, the reader is directed to the earlier guidance. For those practices
described previously and for which additional information is available, new information is
presented; the reader is directed to refer to both this chapter and the 2007 guidance. For those
practices that are not included in the earlier guidance and have been identified as appropriate
for use in the Chesapeake Bay, detailed information is provided to describe the practice and
discuss appropriate applications and purpose as well as information on practice costs and
performance if available.
3.1 Existing Practices
The practices listed in Table 7-9 are described in detail in the 2007 National Hydromodification
guidance document. For additional information on the practices, see that document. Limited
additional information exists regarding these practices and their use in the Chesapeake Bay
watershed.
Table 7-9. Practices described in the 2007 guidance document
Practice
Behavioral Barriers
Branch Packing
Breakwaters
Brush Layering
Bulkheads and Seawalls
Check Dams
Coconut Fiber Roll
Collection Systems
Construction Runoff Intercepts
Construction Management
Dormant Post Plantings
Erosion Control Blankets
Fish Ladders
IM1
X
X
IM2
X
X
X
X
X
IMS
X
X
X
IM4
IMS
X
X
X
7-20
Chapter 7. Hydromodification
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
Table 7-9. Practices described in the 2007 guidance document (continued)
Practice
Fish Lifts
Groins
Locate Potential Land Disturbing Activities away from Critical Areas
Mulching
Phase Construction
Physical Barriers
Preserve Onsite Vegetation
Project Scheduling
Retaining Walls
Return Walls
Re vegetate
Root Wad Revetments
Sediment Basin/Rock Dams
Sediment Fences
Sediment Traps
Seeding
Site Fingerprinting
Sodding
Soil Protection
Surface Roughening
Training ESC
Transfer of Fish Runs
Tree Revetments
Wildflower Cover
IM1
X
X
X
X
IM2
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
IMS
X
X
X
IM4
IMS
X
X
Note: Clicking this link will access the 2007 document (National Management Measures to Control Non-point Source
Pollution from Hvdromodification). To find a specific practice, use the bookmarks.
3.2 Updated and Next Generation Practices
The practice sheets included in the section below are either updates to practices described in
the 2007 guidance document or are next generation tools and techniques that have been
identified as appropriate to address nonpoint source in the Chesapeake Bay watershed.
Chapter 7. Hydromodification
7-21
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
3.2.1 Advanced Hydroelectric Turbines
Description
Advanced hydroelectric turbines are the result of
engineering studies of how the hydraulic components
interact with biota and optimization of turbine
operations designed to reduce effects on juvenile fish
passing through the turbine as it operates.
Application and Purpose
n Protect Streambanks and
Shorelines from Erosion
D Control Upland Sources of
Sediment and Nutrients at Dams
D Restore In-stream and Riparian
Habitat Function
0 Reduce Pollutant Sources
through Operational and Design
Management
D Restore Stream and Shoreline
Physical Characteristics
Most research on advanced hydroelectric turbines has
been conducted by electric power producers in the
western United States. Improving the survival of
juvenile fish by encouraging development of low impact turbines is also being pursued on a
national scale by the U.S. Department of Energy and the U.S. Army Corps of Engineers.
Research includes biological studies of turbine passage at field sites and hydraulic model
investigations leading to innovative concepts for turbine design that will have environmental
benefits and maintain efficient electrical generation.
Efficiency Data
Previous field studies have shown that improvements in the design of turbines have increased
the survival of juvenile fish and researchers continue to examine the causes and extent of
injuries from turbine systems, as well as the significance of indirect mortality and the effects of
turbine passage on adult fish. Ongoing research is continuing to assess improvements in
turbine design and operation as well as modeling to assess turbine-passage survival.
7-22
Chapter 7. Hydromodification
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
3.2.2 Bank Shaping and Planting
Description
Bank shaping and planting involves regrading a n Protect Streambanks and
... . .,• . . . , , , , • Shorelines from Erosion
streambank to establish a stable slope angle, placing
topsoi! and other malaria! needed for p!ant growth on D 'SSXXZXfXEZ a! Dams
the streambank, and selecting and installing _ _ . , . . _. .
D Restore In-stream and Riparian
appropriate plant species on the streambank. Habitat Function
D Reduce Pollutant Sources
through Operational and Design
Application and Purpose Management
0 Restore Stream and Shoreline
Bank shaping and planting is most successful on Physical Characteristics
streambanks where moderate erosion and channel
migration are anticipated. Reinforcement at the toe of
the bank is often required, particularly where flow velocities exceed the tolerance range for
plantings and where erosion occurs below base flows.
Efficiency Data
Nearly 400 rock riprap grade-control structures (GCS) were recently placed in streams of
western Iowa to reduce streambank erosion and protect bridge infrastructure and farmland. In
that region, streams are characterized by channelized reaches, highly incised banks, and silt
and sand substrates that normally support low macroinvertebrate abundance and diversity.
Therefore, GCS composed of riprap provide the majority of coarse substrate habitat for benthic
macroinvertebrates in these streams. Litvan et al. (2008) sampled 20 sites on Walnut Creek,
Montgomery County, Iowa, to quantify macroinvertebrate assemblage characteristics (1) on
GCS riprap, (2) at sites 5-50 meters (m) upstream of GCS, (3) at sites 5-50 m downstream of
GCS and (4) at sites at least 1 kilometer (km) from any GCS (five sites each). Macroinvertebrate
biomass, numerical densities and diversity were greatest at sites with coarse substrates,
including GCS sites and one natural riffle site and relatively low at remaining sites with soft
substrates. Densities of macroinvertebrates in the orders Ephemeroptera, Trichoptera, Diptera,
Coleoptera and Acariformes were abundant on GCS riprap. Increases in macroinvertebrate
biomass, density, and diversity at GCS might improve local efficiency of breakdown of organic
matter and nutrient and energy flow, and provide enhanced food resources for aquatic
vertebrates. However, lack of positive macroinvertebrate responses immediately upstream and
downstream of GCS suggest that positive effects might be restricted to the small areas of
streambed covered by GCS. Improved understanding of GCS effects at both local and
ecosystem scales is essential for stream management when these structures are present.
Chapter 7. Hydromodification 7-23
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
3.2.3 Brush Mattressing
Description
A brush mattress is a layer (mattress) of interlaced live D Protect Streambanks and
, . „ ..... Shorelines from Erosion
branches placed on a bank face, often with a live
fascine and/or rock at the base. The mat is then D ' a! Dams
secured to the bank by live and/or dead stakes and _ _ . , . . _. .
D Restore In-stream and Riparian
partially covered with fill soil to initiate growth of the Habitat Function
cuttings. n Reduce Pollutant Sources
through Operational and Design
Management
Application and Purpose 0 Restore Stream and Shoreline
Physical Characteristics
Brush mattressing is commonly used in Europe for
streambank protection. It involves digging a slight
depression on the bank and creating a mat or mattress from woven wire or single strands of
wire and live, freshly cut branches from sprouting trees or shrubs. Branches approximately one
inch in diameter are normally cut 6 to 9 feet long (the height of the bank to be covered) and laid
in criss-cross layers with the butts in alternating directions to create a uniform mattress with few
voids. The mattress is then covered with wire secured with wooden stakes 2.5 to 4 feet long. It
is then covered with soil and watered repeatedly to fill voids with soil and facilitate sprouting;
however, some branches should be left partially exposed on the surface. The structure might
require protection from undercutting by placement of stones or burial of the lower edge. Brush
mattresses are generally resistant to waves and currents and provide protection from the
digging out of plants by animals. Disadvantages include possible burial with sediment in some
situations and difficulty in making later plantings through the mattress.
Brush mattresses can restore riparian vegetation and habitat and enhance conditions for
colonization of native plants. They reduce soil erosion and intercept sediment flowing down the
streambank. After vegetation reaches a height of a few feet, it can improve fish habitat by
shading the stream, lowering water temperatures and offering protection from predators (Allen
and Fischenich 2000). Brush mattresses are also useful on steep, fast-flowing streams.
Cost Data
Costs for brush mattresses range between $3 and $14 per square foot (Allen and Fischenich
2000). Costs can be reduced by using free material from donation sites and volunteer labor.
Costs related to project permitting or planning are not included in the estimate.
7-24 Chapter 7. Hydromodification
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
Design Guidance and Additional Information
Installation guidelines are available from the U.S. Department of Agriculture-Forest Service
(USDA-FS) So/7 Bioengineering Guide (USDA-FS 2002). Under the Ecosystem Management
and Restoration Research Program (EMRRP), the U.S. Army Corps of Engineers has presented
research on brush mattresses in a technical note (Brush Mattresses for Streambank Erosion
Control).
Chapter 7. Hydromodification 7-25
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
3.2.4 Cross Vanes
Description
A rock cross vane is a stone structure consisting of
footer and vane rocks constructed in a way that
provides grade control and reduces bank erosion. The
vane is composed of a center section perpendicular to
the streambanks joined to two arms that extend into the
streambank at the channel flow height. The rock cross
vane accumulates sediment behind the vane arms,
directs flow over the cross vane, and creates a scour
pool downstream of the structure.
D Protect Streambanks and
Shorelines from Erosion
D Control Upland Sources of
Sediment and Nutrients at Dams
D Restore In-stream and Riparian
Habitat Function
D Reduce Pollutant Sources
through Operational and Design
Management
0 Restore Stream and Shoreline
Physical Characteristics
Application and Purpose
Low-profile, in-stream structures, such as cross vanes, are primarily used to create aquatic
habitat in the form of scour pools and for grade control on incising streams and rivers.
Additionally, they are well-suited for channeling flow away from unstable banks. Cross vanes
are typically suited for use in moderate- to high-gradient streams. When constructed and
spaced properly, cross vanes can simulate the natural pattern of pools and riffles occurring in
undisturbed streams while forming gravel deposits which fish use as spawning grounds. Cross
vanes can also be used to stabilize banks when designed properly. Cross vanes should be
avoided in channels with bedrock beds or unstable bed substrates, and streams with naturally
well-developed pool-riffle sequences.
Cross vanes are appropriate for the following:
• Stabilization of a vertically unstable stream bed requires grade control
• To direct erosional forces away from the streambanks and to the center of the channel
• When fish habitat enhancement and grade control are both desired
• For bridge protection. Cross vanes provide grade controls, prevent lateral migration of
channels, increase sediment transport capacity and competence, and reduce footer
scour
• To enhance or create recreational paddling opportunities
• Most suitable for rapid-dominated stream systems with gravel/cobble substrate
7-26
Chapter 7. Hydromodification
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
Cost Data
Construction costs for cross vanes are highly variable, depending on the design, size of the
stone, availability of materials, and site constraints.
Chapter 7. Hydromodification 7-27
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
3.2.5 Establish and Protect Stream Buffers
Description
Stream buffers can provide cost-effective, long-term
pollutant removal without having to construct and
maintain structural controls. Specific stream buffer
practices include establishing a stream buffer
ordinance, developing vegetative and use strategies
within management zones, establishing provisions for
stream buffer crossings, integrating structural runoff
management practices where appropriate, and
developing stream buffer education and awareness
programs.
0 Protect Streambanks and
Shorelines from Erosion
D Control Upland Sources of
Sediment and Nutrients at Dams
0 Restore In-stream and Riparian
Habitat Function
D Reduce Pollutant Sources
through Operational and Design
Management
D Restore Stream and Shoreline
Physical Characteristics
Application and Purpose
Establishing and protecting these areas is important to water quality protection. Land acquisition
programs help to preserve areas considered critical to maintaining surface water quality. Stream
buffers can also protect and maintain near-stream vegetation that attenuates the release of
sediment into stream channels. Stream buffers should be protected and preserved as a
conservation area because they provide many important functions and benefits, including the
following:
• Providing a right-of-way for lateral movement
• Conveying floodwaters
• Protecting streambanks from erosion
• Treating runoff and reducing drainage problems from adjacent areas
• Providing nesting areas and other wildlife habitat functions
• Mitigating stream warming
• Protecting wetlands
• Providing recreational opportunities and aesthetic benefits
• Increasing adjacent property values
7-28
Chapter 7. Hydromodification
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
Efficiency Data
The biennial National Water Quality Inventory surveys shows no reduction in the percentage of
degraded miles of streams since the early 1990s despite an exponential increase in river
restoration projects to improve water quality, enhance in-stream habitat and manage the
riparian zone (Langendoen et al. 2009). This might suggest that many river restoration projects
fail to achieve their objectives. This was found to be partly from a lack of understanding of the
dynamics of the degraded riverine system and its interaction with the riparian zone. Vegetative
riparian conservation measures are commonly used to stabilize failing streambanks. The shear
strength of bank soils is greatly affected by the degree of saturation of the soils and root
reinforcement provided by riparian vegetation. An integrated model was used to study the
effectiveness of woody and herbaceous riparian buffers in controlling streambank erosion of an
incised stream in northern Mississippi. Comparison of model results with observations showed
that pore-water pressures are accurately predicted in the upper part of the streambank, away
from the groundwater table. Simulated pore-water pressures deviate from those observed lower
in the streambank near the phreatic surface. These discrepancies are mainly caused by
differences in the simulated location of the phreatic surface and simulated evapotranspiration in
case of the woody buffer. The modeling exercise further showed that a coarse rooting system,
e.g., as provided by trees, significantly reduced bank erosion rates for this deeply incised
stream.
The impact of different management of similar riparian land uses was studied in two pasture
subreaches by Zaimes et al. (2008), who found that total streambank soil loss can be estimated
by using magnitude of bank erosion, soil bulk density, and severely eroded bank area.
Significant seasonal and yearly differences in magnitude of bank erosion and total soil loss were
partially attributed to differences in precipitation and associated discharges. Riparian forest
buffers had significantly lower magnitude of streambank erosion and total soil loss than the
other two riparian land uses. Establishing riparian forest buffers along all the nonbuffered
subreaches would have reduced streambank soil loss by an estimated 77 to 97 percent,
significantly decreasing sediment in the stream. The pasture with cattle had consistently higher
magnitudes of bank erosion than those for the pasture with horses for the entire study period.
The pasture with cattle was also the only subreach to show an increase in eroding stream
length (3 percent) and eroding area (10 percent) from 1998 to 2002. Riparian vegetation and
land use are an integral part of streambank erosion, but high precipitation levels and associated
high discharges can also influence the erosion process. Differences in the magnitude of bank
erosion, severely eroded bank lengths and areas, and soil losses throughout this study are
partially attributable to differences in precipitation that were associated with the occurrence of
substantial discharge events. Other processes such as freeze and thaw events and season,
which affected the density of the vegetation cover of the watershed were also implicated. The
variation in soil losses from streambank erosion over the entire study period also suggest that a
data set of many years is needed to get a good estimate of bank erosion contributions to stream
Chapter 7. Hydromodification 7-29
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
sediment load. One-year data sets can be misleading in estimating the long-term contributions
of bank erosion to stream sediment loads.
A partnership involving more than a dozen organizations, agencies and businesses joined
forces to construct a 800-foot living shoreline that rebuilt the barrier between the creek and the
cove with natural materials, which was then planted with native plants to provide more stability
(Blankenship 2009). The project relied on volunteers and multiple funders and was the first
project in the Chesapeake Bay that involved the Corporate Wetland Restoration Partnership,
which brings together government on environmental projects. That type of restoration project
was envisioned in the draft habitat report that responded to President Barack Obama's
Chesapeake Bay Executive Order of May of 2009. The report calls for using partnerships to
build strategically placed "largescale, multifaceted restoration [projects] targeted at improving
living resources."
Besides the living shoreline, curved rock structures were built at both ends of the cove to protect
it from waves and to trap sand that will serve as beach habitat. The project included the
construction of an oyster reef, which serves as habitat and buffers the shoreline from waves.
Shallow water habitats, which had largely eroded away, were rebuilt and planted with marsh
grasses. Reestablishing shallow water habitat, including oyster beds and mussel beds, will
serve as foraging grounds for sea ducks, which should keep Hail Creek as one of the top five
waterfowl habitats for years to come.
Langendoen et al. (2009) found that restoration projects could benefit from using proven models
of stream and riparian processes to guide restoration design and to evaluate indicators of
ecological integrity. The USDA has developed two such models: CONCEPTS and Riparian
Ecosystem Management Model (REMM). Those models have been integrated to evaluate the
impact of edge-of-field and riparian conservation measures on stream morphology and water
quality. The physical process modules of the channel evolution model CONCEPTS and the
riparian ecosystem model REMM have been integrated to create a comprehensive, stream-
riparian corridor model that will be used to evaluate the effects of riparian buffer systems on in-
stream environmental resources. The capability of REMM to dynamically simulate streambank
hydrology and plant growth has been used to study the effectiveness of a deciduous tree stand
and an eastern gamagrass buffer in controlling the stability of a streambank of an incised
stream in northern Mississippi.
Cost Data
A study of cost-effectiveness analysis of vegetative filter strips and in-stream half-logs as tools
for recovering scores on a fish index of biotic integrity (IBI) in the upper Wabash River in Indiana
provided baseline data and a framework for planning and determining the cost of stream
7-30 Chapter 7. Hydromodification
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
restoration (Frimpong et al. 2006). The authors found that costs per unit increase in IBI score
with vegetative filter strips as the method of restoring stream health decreases with increasing
stream order and decreasing recovery time. Another finding was that vegetative filter strips are
likely a useful method, given cost considerations, for recovering lost IBI scores in an agricultural
watershed. Three assumptions were made about recovery time for IBI scores (5, 15, and 30
years) and social discount rates (1, 3, and 5 percent), which were tested for sensitivity of the
estimated cost-effectiveness ratios. The effectiveness of vegetative filter strips was estimated
using fish I Bis and riparian forest cover from 49 first-order to fifth-order stream reaches. Half-log
structures had been installed for approximately 2 years in the watershed before the study and
provided a basis for estimates of cost and maintenance. Cost-effectiveness ratios for vegetated
filter strips decreased from $387 to $277 per 100 meters for a 1 percent increase in IBI scores
from first- to fifth-order streams with 3 percent discount and 30-year recovery. That cost,
weighted by proportion of stream orders was $360 per 110 meters. On the basis of installation
costs and an assumption of equal recovery rates, half-logs were two-thirds to one-half as cost-
effective as vegetative filter strips. Half-logs would be a cost-effective supplement to filter strips
in low-order streams if they can be proven to recover IBI scores faster than using filter strips
alone.
Design Guidance and Additional Information
Maryland Department of the Environment Water Management Administration. 2000. Maryland's
Waterway Construction Guidelines at
http://www.mde.state.md.us/assets/document/wetlandswaterways/mgwc.pdf. Accessed
February 2010.
Chapter 7. Hydromodification 7-31
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
3.2.6 Flow Augmentation
Description
Flow augmentation is the term used to describe D Protect Streambanks and
,. , , , ...... Shorelines from Erosion
operational procedures such as flow regulation, flood
releases, or fluctuating flow reteases that all have the D 'SSXXZXfXEZ a! Dams
potential for detrimental impacts on downstream _ _ . , . . _. .
D Restore In-stream and Riparian
aquatic and riparian habitat. Several options exist for Habitat Function
creating minimum flows in the tailwaters below dams. 0 Reduce Pollutant Sources
Sluicing is the practice of releasing water through the through Operational and Design
sluice gate rather than through the turbines. For Management
portions of the waterway immediately below the dam, D ^ftore ,s/lrueam and Shoreline
Physical Characteristics
the steady release of water by sluicing provides
minimum flows with the least amount of water
expenditure. Turbine pulsing is a practice involving the release of water through the turbines at
regular intervals to improve minimum flows. In the absence of turbine pulsing, water is released
from large hydropower dams only when the turbines are operating, which is typically when the
demand for power is high.
Application and Purpose
The downstream effects that can be mitigated by using flow augmentation are highly variable as
each impounded system is unique. The location of a dam within a river system, its age, depth
and surface area, the hydraulic residence time, the regional climate, operation of the dam, and
chemistry of the inflowing waters all influence how impoundments affects downstream water
quality. Hydropower producers are faced with two environmental problems that can affect the
water quality in areas downstream from dams (i.e., tailwaters). These are low concentrations of
dissolved oxygen in the water released through the dam during generation and dry riverbeds
that result when hydropower generation is shut off. Selecting any particular technique as the most
cost-effective is site-specific and depends on several factors including adequate performance to
achieve the desired in-stream and riparian habitat characteristic, compatibility with other
requirements for operation of the hydropower facility, availability of materials, and cost.
Efficiency Data
Numerous studies have examined the effects of flow regulation on water quantity and quality by
comparing an impounded system with an adjacent unimpounded system. Mitigation techniques
7-32 Chapter 7. Hydromodification
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
to improve ecosystem health downstream of impoundments rely on the restoration of a more
natural flow regime by creating and implementing site-specific, dam management plans.
A study by Ahearn et al. (2005) examined the effects of flow regulation on water quantity and
quality by comparing an impounded system with an adjacent unimpounded system in California.
The study showed that a strong seasonal cycle for total suspended solids (TSS), NO3-N, TN,
PO4-P, TP, dissolved silicon, specific conductivity and flow into reservoirs in the lower
Mokelumne River was attenuated by physical and chemical fluctuations creating a weak
seasonal pattern. Dissolved silicon and TSS were the two constituents most efficiently
sequestered by the reservoirs. While the reservoirs acted as traps for most constituents, NO3-N
and PO4-P were produced during the drier years of the study, 2001 and 2002. In contrast, the
unimpounded reference reach in the Cosumnes River was an annual source for all constituents
measured. The Cosumnes delivers its highest NO3-N concentrations during the winter months
(December-April), while peak concentrations in the Mokelumne occur during the snowmelt
(May-July) and baseflow (August-November) seasons. Because of downstream N limitation,
the temporal shift in NO3-N export might be contributing to accelerated algal growth in the reach
immediately downstream and eventually to algal biomass loading to the downstream
Sacramento-San Joaquin Delta.
In 2003 the Housatonic Valley Association (HVA) partnered with The Massachusetts Riverways
Program (in the Department of Fish & Game) to begin measuring streamflow on several rivers
below recreational reservoirs. The measurements indicated unnatural variations in streamflow at
several sites that are detrimental to downstream aquatic life and habitat. A more naft/ra/flow
regime is being reestablished in the streams to improve their ecological condition. The HVA has
been meeting with Conservation Commissions, Lake Associations, and other stakeholders to
develop guidelines for managing flows out of reservoirs. The goal is to improve ecosystem
health downstream of impoundments by restoring a more natural flow regime by creating site-
specific, dam management plans in the form of monthly flow recommendations using a
methodology jointly developed by the U.S. Geological Survey (USGS) and the Massachusetts
Department of Conservation and Recreation (OCR). The long-term goal is to develop guidance
for Conservation Commissions throughout the Commonwealth to help them craft Orders of
Conditions for dam projects that include specific requirements to provide a year-round flow
regime appropriate to the natural variability of the ecosystem downstream of the impoundment.
Cost Data
Since the early 1990s, the Tennessee Valley Authority (TVA) has spent about $60 million to
address dissolved oxygen problems, including installing equipment to increase dissolved
oxygen concentrations below 16 dams and operational changes and installing additional
equipment to ensure minimum water flows through all its dams. TVA has since completed a
Chapter 7. Hydromodification 7-33
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
second round of improvements by installing or enhancing oxygen systems at nine projects and
two new autoventing turbines have been installed at the Boone Dam. The additional
oxygenation capacity will help offset the increased oxygen demands associated with delaying
the seasonal drawdown of TVA reservoirs.
7-34 Chapter 7. Hydromodification
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
3.2.7 Joint Planting
Description
Joint planting involves tamping live stakes of rootable
plant material or rooted cuttings into soil in the
interstices of porous revetments, riprap, or other
retaining structures.
Joint planting is useful where rock riprap is required or
already in place. It is successful 30 to 50 percent of the
time, with first year irrigation improving survival rates.
Live cuttings must have side branches removed and
bark intact. They should range from 0.5 to 1.5 inches in
diameter and be long enough to extend well into the
soil, reaching into the dry season water level.
D Protect Streambanks and
Shorelines from Erosion
D Control Upland Sources of
Sediment and Nutrients at Dams
D Restore In-stream and Riparian
Habitat Function
D Reduce Pollutant Sources
through Operational and Design
Management
0 Restore Stream and Shoreline
Physical Characteristics
Application and Purpose
Joint planting can improve aquatic habitat by providing food and cover in the riparian zone and
over the water when they are used in close proximity to the edge of the stream. Stone used at
the base of the joint planting produces substrates suited for an array of aquatic organisms.
Some of these organisms adapt to living on and within the rocks and some attach to the leaves
and stems. The leaves and stems can also become food for shredders.
Species for joint planting systems can be selected to provide color, texture, and other attributes
that add a pleasant, natural landscape appearance. Such plants for these systems include
willow (Sa//x spp.), which tends to be the best from an adventitious rooting perspective and is
normally an excellent choice. However other species such as poplar (Populus spp.), Viburnum
spp., Hibiscus spp., shrub dogwood (Cornus spp.) and buttonbush (Cephalanthus) also work
well. After establishment, joint planting system can reduce nonpoint pollution by intercepting
sediment and attached pollutants that otherwise enter the stream from overbank flow areas.
Cost Data
Joint planting ranges in cost between $1 to $5 per square foot (Gray and Sotir 1996). Costs do
not include riprap and assumes a spacing of four cuttings per square yard.
Chapter 7. Hydromodification
7-35
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
Design Guidance and Additional Information
Installation guidelines are available from the USDA-FS So/7 Bioengineering Guide (USDA-FS
2002) and the USDA NRCS Engineering Field Handbook, Chapter 18 (USDA-NRCS 1992).
7-36 Chapter 7. Hydromodification
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
3.2.8 Legacy Effects of Dams and Dam Removal
Description
Dam removal is the process of dismantling and D Protect Streambanks and
, , , , . , , Shorelines from Erosion
removing unsafe, unwanted or obsolete dams and
restoring the original stream gradient to the extent D 'SSXXZXfXEZ a! Dams
possible
0 Restore In-stream and Riparian
Habitat Function
. D Reduce Pollutant Sources
Application and Purpose through Operational and Design
Management
Dams serve a variety of important social and _ „ „
0 Restore Stream and Shoreline
environmental purposes, including water supply, flood Physical Characteristics
control, power generation, wildlife habitat and . ,
recreation (USEPA 2007). Dam removal is undertaken
either by owners of the dam or by public agencies and might become necessary for various
reasons. These include, most notably, the physical or structural deterioration of the dam
resulting in a public safety risk, sediment accumulation in the impoundment/reservoir behind the
dam and corresponding deleterious effects on the quality and quantity of water supplies. There
are many things to consider when removing a dam, one of which is the function(s) of the dam
and the status of that function (active versus inactive). Sometimes, the need for the dam is no
longer as important as it once was, usually because of economic considerations. Finally,
ecological concerns sometimes drive the need for dam removal. For example, migratory fish
passage throughout United States rivers and streams is obstructed by more than 2 million dams
and many other barriers such as blocked, collapsed, and perched culverts (USEPA 2007).
Because dams are capital-intensive, long-term ventures, the opportunity for dam removal
typically occurs infrequently, often corresponding to their periodic licensing renewal.
Efficiency Data
Many rivers and streams of the Mid-Atlantic region have been altered by postcolonial floodplain
sedimentation (legacy sediment) associated with numerous milldams. Several studies have
shown the effect that colonization has had on the deposition of sediment into floodplains and
estuaries (Jacobson and Coleman 1986; Hilgartner and Brush 2006). During the same time,
many mill dams were installed, trapping the sediment behind them along with nutrients washed
away from farm lands. Beavers played an important role in creating anabranching stream
networks in the Mid-Atlantic region during pre-settlement times, and beavers were an important
factor in creating wetlands, performing a similar function to dams in sediment retention.
Chapter 7. Hydromodification 7-37
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
Little Conestoga Creek, Pennsylvania, a tributary to the Susquehanna River and the
Chesapeake Bay, is one of these streams. Floodplain sedimentation rates, bank erosion rates,
and channel morphology were measured annually during 2004-2007 at five sites along a 28-km
length of Little Conestoga Creek with nine colonial era milldams (one dam was still in place in
2007). A study by (Schenk and Hupp 2009) was part of a larger cooperative effort to quantify
floodplain sedimentation, bank erosion, and channel morphology in a high sediment yielding
region of the Chesapeake Bay watershed.
Data from the five sites were used to estimate the annual volume and mass of sediment stored
on the floodplain and eroded from the banks for 14 segments along the 28-km length of creek. A
bank and floodplain reach based sediment budget (sediment budget) was constructed for the 28
km by summing the net volume of sediment deposited and eroded from each segment. Mean
floodplain sedimentation rates for Little Conestoga Creek were variable, with erosion at one
upstream site (5 mm/year) to deposition at the other four sites (the highest was 11 mm/year)
despite over a meter of floodplain aggradation from postcolonial sedimentation. Mean bank
erosion rates range between 29 and 163 mm/year among the five sites. Bank height increased
1 m for every 10.6 m of channel width, from upstream to downstream (R2 = 0.79, p < 0.0001)
resulting in progressively lowered hydraulic connectivity between the channel and the floodplain.
A knickpoint, approximately 9 km upstream of the dam, has produced a net erosional
environment in the upstream two river segments. The floodplain experienced short periods of
inundation nearly annually at the USGS stream gage, between the knickpoint and the dam,
despite the heightened banks from postcolonial sedimentation and subsequent dam removals.
Sediment trapping was recorded at four of the five study sites, indicating that the aggraded Little
Conestoga Creek floodplain still functions as a sediment sink.
The study concluded that dam removals have many benefits, but they come with the cost of
remobilizing large amounts of sediment. Managers and policy makers in the Northeast and Mid-
Atlantic states will have the additional burden of managing the storage and transport of legacy
sediment. Dam removals in these regions can lead to large and sustained sediment pulses as
legacy sediment is remobilized and transported further downstream, where increased
sedimentation is a critical concern for imperiled estuarine resources, in this case the
Chesapeake Bay.
Gravel-bedded streams are thought to have a characteristic meandering form bordered by a self
formed, fine-grained floodplain. This ideal guides a multibillion-dollar stream restoration industry.
Walter and Merritts (2008) mapped and dated many of the deposits along Mid-Atlantic streams
that formed the basis for this widely accepted model. These data, as well as historical maps and
records, show instead that before European settlement, the streams were small anabranching
channels within extensive vegetated wetlands that accumulated little sediment but stored
7-38 Chapter 7. Hydromodification
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
substantial organic carbon. Subsequently, 1 to 5 meters of slackwater sedimentation, behind
tens of thousands of 17th- to 19th-century milldams, buried the presettlement wetlands with fine
sediment. These findings show that most floodplains along mid-Atlantic streams are actually fill
terraces, and historically incised channels are not natural archetypes for meandering streams.
The study concludes that fluvial aggradation and degradation in the eastern United States were
caused by human-induced base level changes from the following processes:
• Widespread milldam construction that inundated presettlement valleys and converted
them into a series of linked slackwater ponds, coupled with deforestation and agricultural
practices that increased sediment supply
• Sedimentation in ubiquitous millponds that gradually converted these ponds to sediment-
filled reservoirs
• Subsequent dam breaching that resulted in channel incision through postsettlement
alluvium and accelerated bank erosion by meandering streams
• The formation of an abandoned valleyflat terrace and a lower inset floodplain, which
explains why so many eastern streams have bankfull (discharge) heights that are much
lower than actual bank heights (note that assessments of bankfull discharge are crucial
to estimates of flood potential and to design criteria for stream restoration).
A study by Skalak et al. (2009) demonstrated that the effects of dams on downstream channel
morphology are minor. No significant differences in the water surface slope upstream and
downstream of dams were observed. The study found that although monitoring studies of dam
removals are becoming more common (Wildman and MacBroom; Bushaw-Newton et al. 2002;
Doyle et al. 2003; Chang 2008) empirical knowledge of the effects of dam removal is still limited
and most observations and conceptual models tend to focus on the transient effects of dam
removal, the shorter-term patterns of upstream sediment mobilization and downstream
sediment storage.
Very little research has been conducted on the long-term effects of dam removal, although Graf
(2006) suggests that one of the most important unanswered questions involves the likely course
of channel change following dam removal. Skalak et al. suggest that the results of their study
can provide some useful estimates of the long-term effects of dam removal on downstream
channels because the reaches upstream of existing dams provide a useful surrogate for the
channel downstream before dam construction. If the dam is removed, the following scenario is
likely to occur. For an initial period of adjustment, sediment will be eroded from reservoir
deposits upstream, and a transient sediment pulse will likely pass into and through the reach
below the dam (Pizzuto 2002). During this period, changes in channel morphology and bed
composition might be expected. However, after the new channel within the reservoir reach has
Chapter 7. Hydromodification 7-39
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
stabilized, the supply of sediment and distribution of discharges should approach predam levels,
and the channel will slowly stabilize.
The issue of removing dams is highly controversial. Dams provide water quality benefits by
removing sediment and nutrients (Harrison et al. 2009), a function historically performed by
beaver dams and large woody debris (Valett et al. 2002). While providing water quality benefits,
dams also hinder fish migration, limit sediment transport, and alter flow regimes. Because dams
and their reservoirs persist for decades, river channels typically adjust to the altered hydrologic
and sediment transport regimes that dams impose. Dam removal itself therefore represents a
geomorphic disturbance to a quasi-adjusted riverine system. Removing a dam unleashes
cascades of erosional and depositional processes that propagate both upstream and
downstream, with the upstream response driving the downstream response.
The responses of aquatic ecosystems to elevated sediment loads and transformed channel
morphology and hydrology are difficult to predict. Because dam presence and operation are
known to be detrimental to preexisting aquatic ecosystems, dam removal is assumed to be
beneficial, and emerging studies have supported ecological resiliency after removal (Stanley et
al. 2002). Dam removal can also wreak havoc on already highly disturbed ecosystems. Further,
the sediment released following a dam removal will inevitably be harmful to some downstream
biota. The possibility exists that reservoirs can store high levels of contaminants, including
heavy metals and other organic and inorganic compounds. Release of such materials after dam
removal can create contaminant plumes with wide-ranging environmental consequences.
The benefits of removing dams include restoring flow fluctuations, allowing sediment transport,
preventing temperature fluctuations, and allowing fish migration. When natural flow fluctuations
are restored to a river, biodiversity and population densities of native aquatic organisms
increase. Wetlands adjacent to rivers also benefit from dam removal. Riparian areas would
likely flood more frequently, promoting riparian plant growth, revitalizing inland wetlands, and
creating small, ephemeral ponds, which serve as nurseries for aquatic species. Dams can alter
a river's temperature by releasing water from the bottom of the impoundment where cooler
water resides, so dam removal can restore a river's natural water temperature range.
Reproductive success, which often depends on appropriate timing for reaching spawning or
breeding habits, can be improved by the removal of dams. Furthermore, dam removal
decreases the risk of mortality for organisms that would otherwise have to pass through dams.
Cost Data
Costs of dam removal are site-specific and can vary from tens of thousands of dollars to
hundreds of millions of dollars, depending on the size and location of the dam (USEPA 2007).
7-40 Chapter 7. Hydromodification
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
3.2.9 Live Crib Walls
Description
Live crib walls are hollow, box-like frameworks of D Protect Streambanks and
, ,, ,. , , Shorelines from Erosion
untreated logs or timbers filled with riprap and
alternating layers of suitable backfill and live branch D 'SSXXZXfXEZ a! Dams
layers and are used for slope, streambank, and _ _ . , . . _. .
D Restore In-stream and Riparian
shoreline protection. Habitat Function
D Reduce Pollutant Sources
through Operational and Design
Application and Purpose Management
0 Restore Stream and Shoreline
Live crib walls are constructed to protect the toes and Physical Characteristics
banks of eroding stream reaches against scour and
undermining, particularly at the outsides of meander
bends where strong river currents are present. The log frameworks provide immediate
protection from erosion while the live branch cuttings contribute long-term durability and
ultimately replace the decaying logs. Additionally, live crib walls are effective in areas where
encroachment into the stream channel should be avoided. When considering these structures
as a stream restoration technique, the following limitations should be considered:
• Live crib walls should not be used where the channel bed is severely eroded or where
undercutting is likely to occur (e.g., where the terrain is rocky or where narrow channels
are bounded by high banks).
• Live crib walls are not intended to resist large lateral earth stresses, therefore their
heights should be limited accordingly (as noted in the installation specifications).
• Live crib walls promote siltation and retain large amounts of bed material; therefore they
require continual monitoring for adverse streamflow patterns.
When choosing and preparing logs and woody cuttings for live crib walls, the following
guidelines should be followed:
• Crib frameworks should be constructed from stripped logs or untreated lumber 4 to 6
inches (10 to 15 centimeters) in diameter.
• Live branches should be cut from fresh, green, healthy parent plants that are adapted to
the site conditions whenever possible.
1. Live branches should be 0.5 to 2.5 inches (1.3 to 6 centimeters) in diameter
and should be long enough to reach the soil at the back of the wooden crib
structure while projecting slightly from the crib face.
Chapter 7. Hydromodification 7-41
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
2. Commonly used woody plants for this measure include willow, poplar, and
alder because they are versatile and have high growth rates with shrubby
habits, fibrous root systems, and high transpiration rates especially when in
leaf.
3. Live branch cuttings should be kept covered and moist at all times and should
be placed in cold storage if more than a few hours elapse before installation.
• Fill soil should be native to the site, when possible, and should contain enough fine
material to allow for the live branches to root and grow readily.
Cost Data
Live crib walls range in cost between $13 to $33 per square foot (Gray and Sotir 1996).
Design Guidance and Additional Information
Installation guidelines are available from the USDA-FS So/7 Bioengineering Guide (USDA-FS
2002) and the USDA NRCS Engineering Field Handbook, Chapter 18 (USDA-NRCS 1992).
Additional Resources
FISRWG (Federal Interagency Stream Restoration Working Group). 1998. Stream Corridor
Restoration: Principles, Processes, and Practices. Federal Interagency Stream
Restoration Working Group.
http://www.nrcs.usda.gov/technical/stream restoration/PDFFILES/APPENDIX.pdf.
ISU (Iowa State University). 2006. How to Control Streambank Erosion: Live Cribwall. Iowa
State University.
http://www.ctre.iastate.edu/erosion/manuals/streambank/live cribwall.pdf.
Mississippi State University, Center for Sustainable Design. 1999. Water Related Best
Management Practices in the Landscape: Live Cribwall. Prepared for the U.S. Department
of Agriculture, Natural Resource Conservation Service, Watershed Science Institute.
http://www.abe.msstate.edu/csd/NRCS-BMPs/pdf/streams/bank/livecribwall.pdf.
Ohio DNR (Department of Natural Resources). No date. Ohio Stream Management Guide: Live
Cribwalls. Ohio Department of Natural Resources.
http://www.ohiodnr.com/water/pubs/fs st/stfs17.htm.
7-42 Chapter 7. Hydromodification
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
3.2.10 Live Fascines
Description
Live fascines are a form of soil bioengineering that n Protect Streambanks and
r.. . , Shorelines from Erosion
uses long bundles of live branch cuttings bound
together in long rows and plaoed in shaHow trenohes D 'SSXXZXfXEZ a! Dams
following the contour on dry slopes and at an angle on _ _ . , . . _. .
D Restore In-stream and Riparian
wet Slopes. Habitat Function
D Reduce Pollutant Sources
through Operational and Design
Application and Purpose Management
0 Restore Stream and Shoreline
Live fascines are suited to steep, rocky slopes, where Physical Characteristics
digging is difficult (USDA-NRCS 1992). When cut from
appropriate species (e.g., young willows or shrub
dogwoods) that root easily and have long straight branches, and when properly installed, they
immediately begin to stabilize slopes. Willow, alder, and dogwood cuttings are well suited for
use in live fascines. Fascine bundles can range from 5 to 30 feet (1.5 to 9 m) in length,
depending on handling and transportation limitations, with diameters ranging from 4 to 10
inches (10 to 25 cm). Untreated twine or wire used to tie the bundles should be at least 2 mm
thick. If inert (dead) stakes are employed to secure the bundles, they should be made from 2 by
4 inch (5 by 10 cm) lumber cut on the diagonal with lengths of 2.5 feet (0.8 m) for cut slopes and
3 feet (0.9 m) for fill slopes. The goal is for natural recruitment to follow once slopes are
secured. Live fascines should be placed in shallow contour trenches on dry slopes and at an
angle on wet slopes to reduce erosion and shallow face sliding. Live fascines should be applied
above ordinary high-water mark or bankfull level except on very small drainage area sites. In
arid climates, they should be used between the high and low water marks on the bank. This
system, installed by a trained crew, does not cause much site disturbance.
Establishing live fascines, also known as wattles, consists of the following:
• Preparing sausage-shaped bundles of live, woody plant cuttings
• Anchoring the bundles in shallow ditches in a slope or streambank with live and/or inert
stout stakes
• Partially burying the fascines to promote growth
Chapter 7. Hydromodification 7-43
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
As with other bioengineering measures, live fascines are an economical method when materials
are locally available. Additionally, live fascines are often an effective measure when employed
to
• Reduce runoff energy, and hence surface erosion, by braking a slope into a series of
shorter slopes
• Protect other bioengineering measures from washout and undercutting
• Replace brush layers on suitable cut slopes (because they are easier to install)
• Protect streambanks from washout and seepage, particularly at toes where water levels
fluctuate only moderately
• Stabilize or protect streambanks
• Provide habitat
• Reduce overland sediment loading
Cost Data
Live fascine costs range from $10 to $30 per foot for 6- to 8-in.bundles. Prices include securing
devices for installation, twine (for fabrication), harvesting, transportation, handling, fabrication,
and storage of the live-cut branch materials, excavation, backfill, and compaction. Costs vary
with design, access, time of year, and labor rates.
Design Guidance and Additional Information
Installation guidelines are available from the USDA-FS So/7 Bioengineering Guide (USDA-FS
2002) and the USDA NRCS Engineering Field Handbook, Chapter 18 (USDA-NRCS 1992).
Under their Ecosystem Management and Restoration Research Program (EMRRP), the U.S.
Army Corps of Engineers presents research on live fascines in a technical note (Live and Inert
Fascine Streambank Erosion Control).
Additional Resources
Massachusetts DEP. 2006. Massachusetts Nonpoint Source Pollution Management Manual:
Live Fascines. Massachusetts Department of Environmental Protection, Boston, MA.
http://proiects.geosvntec.com/NPSManual/Fact%20Sheets/Live%20Fascines.pdf.
Greene County Soil & Water Conservation District. No date. Construction Specification VS-01:
Live Fascines, http://www.gcswcd.com/stream/library/pdfdocs/vs-01.pdf.
7-44 Chapter 7. Hydromodification
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
ISU (Iowa State University). 2006. How to Control Streambank Erosion: Live Fascine. Iowa
State University, http://www.ctre.iastate.edu/erosion/manuals/streambank/live fascine.pdf.
Mississippi State University, Center for Sustainable Design. 1999. Water Related Best
Management Practices in the Landscape: Live Fascine. Prepared for the U.S. Department
of Agriculture, Natural Resource Conservation Service, Watershed Science Institute.
http://abe.msstate.edu/csd/NRCS-BMPs/pdf/streams/bank/livefacine.pdf.
Ohio DNR. No date. Ohio Stream Management Guide: Live Fascines. Ohio Department of
Natural Resources, http://www.ohiodnr.com/water/pubs/fs st/stfs14.pdf.
Chapter 7. Hydromodification 7-45
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
3.2.11 Live Staking
Description
Live staking is used to reestablish streambank
vegetation and help stabilize selected slope areas. This
form of soil bioengineering involves planting live
cuttings from shrubs or trees along the streambank and
is also known as woody cuttings, posts, poles, or stubs.
Stakings provide long-term streambank stabilization
with delayed initial onset and are best used as part of a
system that includes immediate means of buffering
banks from erosive flows (e.g., tree revetments, which
can actually accrue sediments), a component to deter
undercutting at the bed/bank interface (e.g., riprap or
gabions) and a means of reducing the energy of incoming flows at their source.
D Protect Streambanks and
Shorelines from Erosion
D Control Upland Sources of
Sediment and Nutrients at Dams
D Restore In-stream and Riparian
Habitat Function
D Reduce Pollutant Sources
through Operational and Design
Management
0 Restore Stream and Shoreline
Physical Characteristics
Application and Purpose
Live staking is an economical method when local supplies of woody cuttings are readily
available because implementing this measure requires minimal labor. When used effectively,
live stakes can do the following:
• Act to trap soil particles in sediment laden water resulting from the erosion of adjacent
land
• Slow water velocities, trap sediment, and control erosion when organized in clustered
arrays along the sides of gullies
• Repair small earth slips and slumps that are frequently wet
• Help control shallow mass movement when placed in rows across slopes
• Promote bank stabilization
Live staking is a preventative measure and should be employed before severe erosion problems
occur. Additionally, to be effective, live stakes should be
• Planted only on streams with low to moderate flow fluctuations
• Established in the original bank soil on moderate slopes of 4:1(h:v) or less
• Planted where appropriate lighting exists
7-46
Chapter 7. Hydromodification
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
• Used jointly with other restoration techniques especially on slopes with high erosion
rates and incidents of mass wasting
When choosing and preparing woody material for live stakes, managers should follow these
guidelines:
• Live stakes should be cut from fresh, green, healthy, dormant parent plants which are
adapted to the site conditions whenever possible. Commonly used woody plants for this
measure include willow, poplar, and alder because they are versatile and have high
growth rates with shrubby habits, fibrous root systems, and high transpiration rates,
especially when in leaf.
• Live stakes should have a diameter between 0.75 and 1.5 inches (2 to 4 cm) and should
be long enough to reach below the groundwater table so that a strong root system can
quickly develop. At least 1 foot (0.3 m) should be exposed to sunlight. Live woody posts
with diameters up to 10 inches (0.25 m) and lengths ranging from 4 to 6 feet (1.2 to
1.8 m) can also be used at the discretion of the project manager.
• Live stakes should be kept covered and moist at all times and should be placed in cold
storage if more than a few hours elapse between the cutting and replanting times.
• Vegetation selected should be able to withstand the degree of anticipated inundation,
provide year round protection, have the capacity to become well established under
sometimes adverse soil conditions, and have root, stem, and branch systems capable of
resisting erosive flows.
• Specific site requirements and available cutting source will determine size.
Cost Data
The installed cost of live stakes typically ranges from $1 to $2 per stake, depending on local
labor rates, proximity of harvesting area to site, and other site variables.
Design Guidance and Additional Information
Installation guidelines are available from the USDA-FS So/7 Bioengineering Guide (USDA-FS
2002) and the USDA NRCS Engineering Field Handbook, Chapter 18 (USDA-NRCS 1992).
Additional Resources
ISU (Iowa State University). 2006. How to Control Streambank Erosion: Live Stakes. Iowa State
University, http://www.ctre.iastate.edu/erosion/manuals/streambank/live stakes.pdf.
Chapter 7. Hydromodification 7-47
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
Myers, R.D. 1993. Slope Stabilization and Erosion Control Using Vegetation: A Manual of
Practice for Coastal Property Owners. Live Staking. Publication 93-30. Washington
Department of Ecology, Shorelands and Coastal Zone Management Program, Olympia,
WA. http://www.ecy.wa.gov/programs/sea/pubs/93-30/livestaking.html.
Walter, J., D. Hughes, and N.J. Moore. 2005. Streambank Revegetation and Protection: A
Guide for Alaska. Revegetation Techniques: Live Staking. Revised Edition. Alaska
Department of Fish and Game, Division of Sport Fish.
http://www.sf.adfg.state.ak.us/SARR/restoration/technigues/livestake.cfm.
7-48 Chapter 7. Hydromodification
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
3.2.12 Log and Rock Check Dams
Description
Check dams are low structures built across a stream n Protect Streambanks and
perpendicular to the flow. The most common use for Shorelines from Erosion
check dams is to decrease the slope and velocity of a D Contml uP|and Sources of
Sediment and Nutrients at Dams
stream to control erosion.
D Restore In-stream and Riparian
Habitat Function
D Reduce Pollutant Sources
through Operational and Design
Application and Purpose
The plunge pool below a check dam provides excellent Management
fish habitat, and the downstream gravel bar often 0 Restore Stream and Shoreline
, . , , , , ,, . Physical Characteristics
associated with the dam makes an excellent spawning
bed. When used to enhance fish habitat, check dams
should be placed far enough apart to ensure that the pool below a dam is above the backwater
of the next dam downstream. That will reduce the possibility that the habitat pool of the upper
dam can fill with deposits.
When constructed and spaced properly, check dams can simulate the natural pattern of pools
and riffles occurring in undisturbed streams while forming gravel deposits that fish use as
spawning grounds.
Check dams have also been used to prevent the movement of fine sediments into the
mainstream channel, to aerate water, and to raise water levels past culvert invert elevations,
thereby allowing fish passage.
Check dams should be avoided in the following areas:
• Channels with bedrock beds or unstable bed substrates
• Channels without well-developed, stable banks
• Streams with high bedload transport
• Streams with naturally well-developed pools-riffle sequences
• Reaches where the water temperature regime is negatively affected when the current is
slowed
Chapter 7. Hydromodification 7-49
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
Cost Data
Check dams vary widely in cost depending on the design, availability and selection of materials,
and site conditions.
Design Guidance and Additional Information
The following document provides design information and guidance for check dams.
Maryland Department of the Environment Water Management Administration. 2000. Maryland's
Waterway Construction Guidelines.
http://www. mde. state, md. us/assets/document/wetlandswaterways/mgwc. pdf.
7-50 Chapter 7. Hydromodification
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
3.2.13 Marsh Creation and Restoration
Description
Marsh creation and restoration is a useful vegetative
technique that can address problems with erosion of
shorelines. For shoreline sites that are highly sheltered
from the effects of wind, waves, or boat wakes, the fill
material is usually stabilized with small structures,
similar to groins, which extend out into the water from
the land. For shorelines with higher levels of wave
energy, the newly planted marsh can be protected with
an offshore installation of stone that is built either in a
continuous configuration or in a series of breakwaters.
D Protect Streambanks and
Shorelines from Erosion
D Control Upland Sources of
Sediment and Nutrients at Dams
0 Restore In-stream and Riparian
Habitat Function
D Reduce Pollutant Sources
through Operational and Design
Management
0 Restore Stream and Shoreline
Physical Characteristics
Application and Purpose
The exposed stems of marsh plants form a flexible mass that dissipates wave energy. As wave
energy is diminished, the offshore transport and longshore transport of sediment are reduced.
Ideally, dense stands of marsh vegetation can create a depositional environment, causing
accretion of sediments along the intertidal zone rather than continued shore erosion. Marsh
plants also form a dense mat of roots, which can add stability to the shoreline sediments. The
basic approach for marsh creation is to plant a shoreline area in the vicinity of the tide line with
appropriate marsh grass species.
Efficiency Data
Despite rapid growth in river restoration, few projects receive the necessary evaluation and
reporting to determine their success or failure and to learn from experience. As part of the
National River Restoration Science Synthesis, (Alexander and Allan 2006) interviewed
39 project contacts from a database of 1,345 restoration projects in Michigan, Wisconsin, and
Ohio to (1) verify project information; (2) gather data on project design, implementation, and
coordination; (3) assess the extent of monitoring; and (4) evaluate success and the factors that
can influence it. Projects were selected randomly within the four most common project goals
from a national database: in-stream habitat improvement, channel reconfiguration, riparian
management, and water-quality improvement. About half of the projects were implemented as
part of a watershed management plan and had some advisory group. Monitoring occurred in
79 percent of projects but often was minimal and seldom documented biological improvements.
Baseline data for evaluation often relied on previous data obtained under regional monitoring
Chapter 7. Hydromodification
7-51
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
programs using state protocols. Although 89 percent of project contacts reported success, only
11 percent of the projects were considered successful because of the response of a specific
ecological indicator, and monitoring data were underused in project assessment. Estimates of
ecological success, using three criteria from Palmer et al. (2005), indicated that half or fewer of
the projects were ecologically successful, markedly below the success level that project
contacts self-reported, and sent a strong signal of the need for well-designed evaluation
programs that can document ecological enhancements.
7-52 Chapter 7. Hydromodification
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
3.2.14 Multi-Cell Culvert
Description
Roadway crossing, typically of smaller streams, where 0 Protect Streambanks and
, ...... Shorelines from Erosion
the mam culvert at the stream channel is sized for
bankfull discharge and additional culverts are placed D S^a^e^ 2 Dams
on the floodplain to convey overbank flow up to the _ _ . , . . _. .
D Restore In-stream and Riparian
design discharge. Habitat Function
D Reduce Pollutant Sources
through Operational and Design
Application and Purpose Management
D Restore Stream and Shoreline
The use of a multi-cell culvert distributes stream Physical Characteristics
conveyance during larger storm events across a larger . ,
portion of the stream/floodplain cross-section than the
traditional single culvert system resulting in reduced flow velocities and better floodplain
connectivity, In addition the smaller primary culvert can increase flow depths during low flows
enabling fish passage.
Multi-cell culverts typically consists of a primary culvert installed in line with the stream channel
and sized with a cross-sectional area equivalent to the stream at bankfull discharge. One or
more secondary culverts are at floodplain or bankful elevation at variable locations across the
road crossing to provide passage of floodflow. Primary culvert inverts are often placed below the
channel invert to allow water and sediments to pool within the culvert to enable fish passage.
The placement and geometry of the primary culvert is intended to allow the natural transport of
sediment in the stream channel and prevent scour of the streambed because of flow contraction
(Rosgen 1996). The combined capacity of the primary and secondary culverts is the design
flow.
Multi-cell culverts might not be appropriate for streams that are incised or actively incising
streams, exhibit high-flow velocities, or streams that often carry a heavy debris load (Johnson
and Brown 2000). Use of multi-cell culverts in such systems could result in perched culverts and
debris jams, Rosgen (1996) type C or E channels might be most appropriate for use of multi-cell
culverts (Maryland Waterways Construction Guidelines 2000).
Performance
Published data on the performance of multi-cell culverts is primarily limited to fish passage
requirements and assessment of appropriate channels systems. Laboratory-scale model
Chapter 7. Hydromodification 7-53
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
experiments investigating the scour and flow depth characteristics of multi-cell culverts showed
reduction in overall scour pool volume and culvert perching of 52 percent and 55 percent,
respectively (Wargo and Weisman 2006).
Design Guidance and Additional Information
Maryland Department of the Environment Water Management Administration. 2000. Maryland's
Waterway Construction Guidelines at
http://www.mde.state.md.us/assets/document/wetlandswaterways/mgwc.pdf. Accessed
February 2010.
7-54 Chapter 7. Hydromodification
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
3.2.15 Natural Channel Design and Restoration
Description
Natural stream channel design is based on fluvial D Protect Streambanks and
, , . , , Shorelines from Erosion
geomorphology, which is the study of a stream s
interactions with the local climate, geology, topography, D S^a^e^ 2 Dams
vegetation, and land use—how a river carves its _ _ . , . . _. .
0 Restore In-stream and Riparian
channel within its landscape. The underlying concept of Habitat Function
natural stream channel design is to use a stable natural n Reduce Pollutant Sources
channel as a blueprint or template. Such a blueprint, or through Operational and Design
reference reach, will include the pattern, dimension, anagemen
and profile for the stream to transport its watershed's 0 ^ftore ,s/lrueam and Shoreline
Physical Characteristics
flows and sediment as it dissipates energy through its
geometry and in-stream structures. Project design
(channel configuration, structures, nonstructural techniques, and the like) must account for the
stream's ability to transport water and sediment.
Application and Purpose
Natural stream channel design depends on practioners accurately identifying stream
classification types. Stream type is a powerful tool to use in decision making when combined
with knowledge and field experience in natural stream channel design. In addition to providing a
stable condition, natural stream channel design promotes a biologically diverse system. Many of
the structures employed buy time until riparian vegetation becomes established and matures.
Establishing a vegetated buffer that has long-term protection is key to natural design and
provides a number of aquatic and terrestial benefits. Those benefits include root-mass that
stabilizes the bank; shade that buffers stream temperature; leaves that provide energy, food,
and shelter for wildlife; wildlife travel corridors; added roughness to the floodplain which helps to
reduce stream energy; and the uptake of nutrients from the soil.
Many methods exist for classifying streams. One popular method for classification is Rosgen's
Stream Classification System (Rosgen 1996). The purpose of that system is to classify streams
on the basis of quantifiable field measurements to produce consistent, reproducible descriptions
of stream types and conditions. Rosgen's classification hierarchy has four levels: geomorphic
characterization (Level 1), morphological description (Level 2), stream condition assessment
(Level 3), and validation and monitoring (Level 4).
Restoration of the proper dimension will ensure that the stream is connected to the floodplain so
that riparian vegetation and other components that roughen the channel will mitigate damage
Chapter 7. Hydromodification 7-55
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
from flood-flows. Structures used in natural stream channel design such as vanes, cross-vanes,
and root-wads create and maintain pool habitat, which is often minimal in degraded channels. In
other words, they maintain the dimension, pattern and profile (or slope) of the stream. Restored
streams provide for sediment transport and the sorting of bed material that results in the
development of habitat diversity.
All successful natural stream channel designs achieve sediment transport, habitat
enhancement, and bank and channel stabilization. The degree to which projects meet those
goals depends on a project's specific objectives. Ultimately, a stream considered stable or in
equilibrium can carry the sediment load supplied by the watershed without changing its
dimension (cross-sectional area, width, depth, shape), pattern (sinuosity, meander pattern), or
profile (longitudinal pattern and slope), and without aggrading (building up of bottom materials)
or degrading (cutting down into the landscape and abandoning the natural floodplain).
Stream restoration is an increasingly popular management strategy for improving the physical
and ecological conditions of degraded urban streams. In urban catchments, management
activities as diverse as stormwater management, bank stabilization, channel reconfiguration and
riparian replanting can be described as river restoration projects. Restoration in urban streams
is both more expensive and more difficult than restoration in less densely populated
catchments. High property values and finely subdivided land and dense human infrastructure
(e.g., roads, sewer lines) limit the spatial extent of urban river restoration options, while
stormwater and the associated sediment and pollutant loads can limit the potential for
restoration projects to reverse degradation. To be effective, urban stream restoration efforts
must be integrated within broader catchment management strategies. A key scientific and
management challenge is to establish criteria for determining when the design options for urban
river restoration are so constrained that a return toward reference or pre-urbanization conditions
is not realistic or feasible and when river restoration presents a viable and effective strategy for
improving the ecological condition of such degraded ecosystems.
Stream restoration should be performed to provide overall watershed improvement. One
method for achieving that is the Stream Corridor Assessment survey developed by the Maryland
Department of Natural Resources. The survey is a watershed management tool that identifies
environmental problems and helps prioritize restoration opportunities on a watershed basis.
Potential environmental problems commonly identified during the survey include stream channel
alterations, excessive bank erosion, exposed pipes, inadequate stream buffers, fish migration
blockages, trash dumping sites, near-stream construction, pipe outfalls, and unusual conditions.
In addition, the survey records information on the location of potential wetlands creation sites
and collects data on the general condition of in-stream and riparian habitats.
7-56 Chapter 7. Hydromodification
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
Efficiency Data
Restoration activities intended to improve the condition of streams and rivers are widespread
throughout the country but little information exists regarding types of activities and their
effectiveness. (Alexander and Allan 2006) developed a database of 1,345 stream restoration
projects implemented from the years 1970 to 2004 for the states of Michigan, Ohio, and
Wisconsin to analyze regional trends in goals, presence of monitoring, spatial distribution, size,
and cost of river restoration projects. They found that data on individual projects were
fragmented across multiple federal, state, and county agencies, as well as nonprofit groups and
consulting firms. The most common restoration goals reported for this region were in-stream
habitat improvement, bank stabilization, water-quality management, and dam removal. Hassett
et al. 2005 and 2007, analyzed 4,700 stream restoration practices in the Chesapeake Bay
watershed and Bernhardt et.al (2005) compiled a database for 37,099 projects in the National
River Restoration Science Synthesis (NRRSS) database. Those studies found that the primary
reasons for performing stream restoration are the following:
• Bank Stabilization
• Stormwater Management
• Flow Modification
• Channel Reconfiguration
• Fish Passage
• Riparian Management
• In-Stream Species Management
• Dam Removal/Retrofit
• Floodplain Reconnection
• In-Stream Habitat Improvement
• Aesthetics/Recreation/Education
• Water-Quality Management
The effects of upland disturbance and in-stream restoration on hydrodynamics and ammonium
uptake in headwater streams was studied by (Roberts et al. 2007) who found that the delivery of
water, sediments, nutrients, and organic matter to stream ecosystems was strongly influenced
by the catchment of the stream and can be altered greatly by upland soil and vegetation
disturbance. Upland disturbance did not appear to influence stream hydrodynamics strongly, but
it caused significant decreases in in-stream nutrient uptake. In October 2003, coarse woody
Chapter 7. Hydromodification 7-57
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
debris (CWD) was added to one-half of the study streams (spanning the disturbance gradient) in
an attempt to increase hydrodynamic and structural complexity, with the goals of enhancing
biotic habitat and increasing nutrient uptake rates. CWD additions had positive short-term
(within 1 month) effects on hydrodynamic complexity (water velocity decreased and transient
storage zone cross-sectional area, relative size of the transient storage zone, fraction of the
median travel time attributable to transient storage over a standardized length of 200 m, and the
hydraulic retention factor increased) and nutrient uptake (NH4 p uptake rates increased). The
results of this study suggest that water quality in streams with intense upland disturbances can
be improved by enhancing in-stream biotic nutrient uptake capacity through measures such as
restoring stream CWD.
(Bukaveckas 2007) studied the interplay between hydrogeomorphic features and ecosystem
processes within designed channels. Water velocity, transient storage, and nutrient uptake were
measured in channelized (prerestoration) and naturalized (postrestoration) reaches of a 1-km
segment of Wlson Creek (Kentucky) to assess the effects of restoration on mechanisms of
nutrient retention. Stream restoration decreased flow velocity and reduced the downstream
transport of nutrients. Median travel time was 50 percent greater in the restored channel
because of lower reachscale water velocity and the longer length of the meandering channel.
Transient storage and the influence of transient storage on travel time were largely unaffected
except in segments where backwater areas were created. First order uptake rate coefficients for
N and P were 30- and 3-fold higher (respectively) within the restored channel relative to its
channelized state. Changes in uptake velocities were comparatively small, suggesting that
restoration had little effect on biochemical demand. Results from this study suggest that channel
naturalization enhances nutrient uptake by slowing water velocity.
Increased delivery of N because of urbanization and stream ecosystem degradation is
contributing to eutrophication in coastal regions of the eastern United States according to
Kaushal et al. (2008) who tested whether geomorphic restoration involving hydrologic
reconnect/on of a stream to its floodplain could increase rates of denitrification at the riparian-
zone-stream interface of an urban stream in Baltimore, Maryland. Rates of denitrification
measured using in situ 15N tracer additions were spatially variable across sites and years and
ranged from undetectable to .200 Ig N (kg sediment). Concentrations of nitrate-N in groundwater
and stream water in the restored reach were also significantly lower than in the unrestored
reach, but this might have also been associated with differences in sources and hydrologic flow
paths. Riparian areas with low, hydrologically connected streambanks designed to promote
flooding and dissipation of erosive force for stormwater management had substantially higher
rates of denitrification than restored high nonconnected banks and both unrestored low and high
banks. Coupled measurements of hyporheic groundwater flow and in situ denitrification rates
indicated that up to 1.16 mg NO3-N could be removed per liter of groundwater flow through one
cubic meter of sediment at the riparian-zone-stream interface over a mean residence time of
7-58 Chapter 7. Hydromodification
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
4.97 d in the unrestored reach, and estimates of mass removal of nitrate-N in the restored reach
were also considerable. Mass removal of nitrate-N appeared to be strongly influenced by
hydrologic residence time in unrestored and restored reaches. Results of the study suggest that
stream restoration designed to reconnect stream channels with floodplains can increase
denitrification rates, that there can be substantial variability in the efficacy of stream restoration
designs, and that more work is necessary to elucidate which designs can be effective in
conjunction with watershed strategies to reduce nitrate-N sources to streams.
Cost Data
The most common restoration activities found by Alexander and Allan (2006) were the use of
sand traps and riprap, and other common activities were related to the improvement of fish
habitat. The median cost was $12,957 for projects with cost data, and total expenditures since
1990 were estimated at $444 million. Over time, the cost of individual projects has increased,
whereas the median size has decreased, suggesting that restoration resources are being spent
on smaller, more localized, and more expensive projects. Only 11 percent of data records
indicated that monitoring was performed, and more expensive projects were more likely to be
monitored. Standardization of monitoring and record keeping and dissemination of findings are
urgently needed to ensure that dollars are well spent and restoration effectiveness is
maximized.
Design Guidance and Additional information
Craig, L.S., M.A. Palmer, D. C. Richardson 1, S. Filoso, E. S. Bernhardt, B. P. Bledsoe, M.W.
Doyle, P. M. Groffman, B. Hassett, S. S. Kaushal, P. M. Mayer, S. M. Smith, and P.R.
Wilcock. 2008. Stream restoration strategies for reducing nitrogen loads. Frontiers in
Ecology and the Environment 6:529-538.
Doll, B.A., G.L Grabow, K.R. Hall, J. Halley, W.A. Harman, G.D. Jennings and D.E. Wise, 2003.
Stream Restoration: A Natural Channel Design Handbook. North Carolina State
University, North Carolina Stream Restoration Institute, Raleigh, NC.
Federal Interagency Stream Restoration Working Group. 1998. Stream Corridor Restoration:
Principles, Processes, and Practices. National Technical Information Service, U.S.
Department of Commerce, Springfield, VA.
Rosgen, D. 1996. Applied River Morphology. Wildland Hydrology, Pagosa Springs, CO.
Shields, F.D. Jr. 1996. Hydraulic and Hydrologic Stability. In River Channel Restoration: Guiding
Principles for Sustainable Projects. A. Brookes and F.D. Shields, Jr (eds.) John Wiley and
Sons, Ltd.
Chapter 7. Hydromodification 7-59
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
3.2.16 Non-Eroding Roadways
Description
Non-eroding roadways refer to practices that reduce
the sediment load to receiving waterbodies from dirt
and gravel roads.
Application and Purpose
The National Management Measures to Control
Nonpoint Sources Pollution from Hydromodification
document (USEPA 2007) has a chapter on the practice
of Non-eroding Roadways. For additional information
on the appropriate use and application of non-eroding
roadways, see the 2007 guide.
0 Protect Streambanks and
Shorelines from Erosion
D Control Upland Sources of
Sediment and Nutrients at Dams
D Restore In-stream and Riparian
Habitat Function
D Reduce Pollutant Sources
through Operational and Design
Management
D Restore Stream and Shoreline
Physical Characteristics
In addition to the information contained in the 2007 guide, the following practices are
recommended to reduce the sediment load from dirt and gravel roads.
Driving Surface Aggregate (DSA)
DSA is a specific gradation of crushed stone developed by the Center for Dirt and Gravel Road
Studies specifically for use as a surface wearing course for unpaved roads. DSA achieves
sediment reductions by decreasing erosion and transport of fine material from the road surface.
Sandstone- and limestone-derived aggregates are preferred.
Raising the Road Profile
Raising the road profile involves importing material to raise the elevation of an unpaved road. It
is typically practiced on roads that have become entrenched (lower than surrounding terrain).
Raising the elevation of the road is designed to restore natural drainage patterns by eliminating
the downslope ditch and providing cover for pipes to drain the upslope ditch. Removing the
downslope ditch will eliminate concentrated flow conveyed in the ditch and create sheet flow.
Raising the road profile achieves sediment reduction by controlling and reducing the volume of
road runoff.
Raising the road profile involves importing fill material to raise the elevation of the roadway up to
the elevation of the surrounding terrain. The road is filled to a sufficient depth as to eliminate the
ditch on the downslope side of the road and encourage sheet flow. Shale and gravel are the
7-60
Chapter 7. Hydromodification
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
most common fill materials for roads. Other potential recycled fill materials include ground glass,
waste sand, automobile tires, clean concrete rubble, and the like.
Grade Breaks
Grade breaks are an intentional increase in road elevation on a downhill grade, which causes
water to flow off of the road surface. It is designed to reduce erosion on the road surface by
forcing water into the ditches or surrounding terrain. Erosion of the road surface is reduced by
forcing runoff laterally off the road. In some cases, grade breaks are used to force water off the
road entirely, serving as an additional drainage outlet. Sites where water is not forced off the
road entirely convey the water into a roadside ditch.
Drainage Outlets
Drainage outlets are designed to capture water flowing in the roadside ditch and force it to leave
the road area. There are two major types of drainage outlets. Turnouts (also called bleeders) or
cutouts outlet water from the downslope road ditch. They usually consist of relatively simple cuts
in the downslope road bank to funnel road drainage away from the road. Drainage that is carried
by the upslope road ditch is usually outletted under the roadway by the use of a crosspipe (also
called culvert, sluice pipe, or tile drain). Installing additional drainage outlets reduces
concentrated flow, peak-flow discharges and sediment transport and delivery from unpaved
roads and ditches into streams, and can increase infiltration. It does not affect sediment
generation from the road surface or deliver in the upslope ditch; thus, all data on sediment
reductions in this chapter are for a downslope ditch only, unless otherwise noted. Drainage
outlets are to be placed in locations that have the least likelihood of reaching streams. If a newly
added outlet conveys sediment to the stream, little, if any, sediment reductions will be obtained.
Berm Removal
A berm is a mound of earthern material that runs parallel to the road on the downslope side.
Berms can be formed by maintenance practices and road erosion that lowers the road elevation
over time. In many cases, the berm is unnecessary and creates a ditch on the downslope side
of the road. The berm can be removed to encourage sheet flow into surrounding land instead of
concentrated flow in an unnecessary ditch. Restoring sheet flow results in decreased runoff and
sediment transport along the roadway, increase infiltration, and reduced maintenance
associated with the road drainage system.
Effectiveness information for non-eroding roadway practices are summarized in Table 7-10.
Chapter 7. Hydromodification 7-61
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
Efficiency Data
Table 7-10. TSS reduction efficiencies estimated for each practice
Technique
Driving Surface Aggregate
Limestone*
Sandstone
Raising the Road Profile
Grade Breaks
Additional Drainage Outlet
Berm Removal
TSS effectiveness
estimate
50%
55%
45%
30%
15%
35%
Total nitrogen (TN) and total phosphorus (TP) removal is minimal with dirt and gravel road
sediment control. One reason is that dirt and gravel roads are not fertilized. The other is that the
environmental benefit association with dirt roads is such that N and P reductions are not
anticipated, nutrient reductions are not a component of the average function of dirt and gravel
roads. If N and P reductions are associated with dirt and gravel roads, sediment reductions
should be tracked.
Design Guidance and Additional Information
For additional information on non-eroding roadways, see the following sources:
Controlling Nonpoint Source Runoff Pollution from Roads, Highways, and Bridges
http://www.epa.gov/owow/nps/roads.html
Erosion, Sediment, and Runoff Control for Roads and Highways
http://www.epa.gov/owow/nps/education/runoff.html
Gravel Roads: Maintenance and Design Manual—the purpose of the manual is to provide clear
and helpful information for doing a better job of maintaining gravel roads. The manual is
designed for the benefit of elected officials, mangers, and grader operators who are
responsible for designing and maintaining gravel roads.
http://www.epa.gov/owow/nps/gravelroads
Low-Volume Roads Engineering Best Management Practices Field Guide
http://zietlow.com/manual/gk1/web.doc
Massachusetts Unpaved Roads BMP Manual
http://www.berkshireplanning.org/download/dirt roads.pdf
7-62
Chapter 7. Hydromodification
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
Planning Considerations for Roads, Highways, and Bridges
http://www.epa.gov/owow/nps/education/planroad.html
Pollution Control Programs for Roads, Highways, and Bridges
http://www.epa.gov/owow/nps/education/control.html
Recommended Practices Manual: A Guideline for Maintenance and Service of Unpaved Roads
http://www.epa.gov/owow/nps/unpavedroads.html
The Road Maintenance Video Set is a five-part video series developed for the USDA-FS
equipment operators that focuses on environmentally sensitive ways of maintaining low-
volume roads, http://www.epa.gov/owow/nps/maint videoset.html
Chapter 7. Hydromodification 7-63
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
3.2.17 Revetments
Description
Revetments are the stabilization of eroding 0 Protect Streambanks and
,,.,,. .... . Shorelines from Erosion
streambanks and for shoreline protection by using
designed structural measures, such as rock riprap, D sSLnt^N^e'nte a! Dams
gabions, precast concrete wall units, and grid pavers. ,_, _ x , x . _. .
D Restore In-stream and Riparian
Habitat Function
. D Reduce Pollutant Sources
Application and Purpose through Operational and Design
Management
The purpose of revetments is to protect exposed or
D Restore Stream and Shoreline
eroded streambanks from the erosive forces of flowing Physical Characteristics
water. They are generally applicable where flow
velocities exceed 6 feet per second or where
vegetative streambank protection is inappropriate and necessary where excessive flows have
created an erosive condition on a streambank.
Because each channel is unique, measures for structural streambank should be installed
according to a design according to specific site conditions. Develop designs according to the
following principles:
• Make protective measures compatible with other channel modifications planned or being
carried out in the channel reaches.
• Use the design velocity of the peak discharge of the 10-year storm or bankfull discharge,
whichever is less. Structural measures should be capable of withstanding greater flows
without serious damage.
• Ensure that the channel bottom is stable or stabilized by structural means before
installing any permanent bank protection.
• Streambank protection should begin at a stable location and end at a stable point along
the bank.
• Changes in alignment should not be done without a complete analysis of effects on the
rest of the stream system for both environmental and stability effects.
• Provisions should be made to maintain and improve fish and wildlife habitat. For
example, restoring lost vegetation will provide valuable shade, food, and/or cover.
• Ensure that all requirements of state law and all permit requirements of local, state, and
federal agencies are met.
7-64 Chapter 7. Hydromodification
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
Typical materials used for revetments are as follows:
Riprap. Riprap is the most commonly used material to structurally stabilize a streambank. While
riprap will provide the structural stabilization necessary, the bank can be enhanced with
vegetative material to slow the velocity of water, filter debris, and enhance habitat.
Gabions. Gabions are rectangular, stone-filled wire baskets. They are somewhat flexible in
armoring channel bottoms and banks. They can withstand significantly higher velocities for the
size stone they contain because of the basket structure. They also stack vertically to act as a
retaining wall for constrained areas.
Reinforced Concrete. Reinforced concrete can be used to armor eroding sections of
streambank by constructing walls, bulk heads, or bank linings. Provide positive drainage behind
such structures to relieve uplift pressures.
Grid Pavers. Grid pavers are modular concrete units with or without void areas can be used to
stabilize streambanks. Units with void areas allows vegetation to establish. Such structures can
be obtained in a variety of shapes or they can be formed and poured in place. Maintain design
and installation in accordance with manufacturer's instructions.
Modular Precast Units. Interlocking modular precast units of different sizes, shapes, heights,
and depths, have been developed for a wide variety of applications. The units serve in the same
manner as gabions. They provide vertical support in tight areas as well as durability. Many types
are available with textured surfaces. They also act as gravity retaining walls. They should be
designed and installed in accordance with the manufacturers' recommendations. Openings in
the units provide drainage and allow vegetation to grow through the blocks. Vegetation roots
add additional strength to the bank.
The National Management Measures to Control Nonpoint Sources Pollution from
Hydromodification document (USEPA 2007) provides various examples of types of revetments.
Design Guidance and Additional Information
Ohio DNR. No date. Ohio Stream Management Guide: Riprap Revetments. Ohio Department of
Natural Resources, http://www.ohiodnr.com/water/pubs/fs st7stfs16.pdf.
Chapter 7. Hydromodification 7-65
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
3.2.18 Riparian Improvements
Description
Riparian improvements are strategies used to restore
or maintain aquatic and riparian habitat around
reservoir impoundments or along the waterways both
upstream of and downstream from dams and include
reducing sediment loading in the downstream
watershed, improving riparian vegetation, eliminating
barriers to fish migration, providing greater in-stream
and riparian habitat diversity, and reducing flow-related
effects on dams.
D Protect Streambanks and
Shorelines from Erosion
D Control Upland Sources of
Sediment and Nutrients at Dams
0 Restore In-stream and Riparian
Habitat Function
0 Reduce Pollutant Sources
through Operational and Design
Management
D Restore Stream and Shoreline
Physical Characteristics
Application and Purpose
Maintaining and improving riparian areas upstream of and downstream from dams is an
important consideration. Riparian improvements might be necessary along smaller-order
streams if their ability to detain and absorb floodwater and stormwater has been impaired—
often the result of removing forest cover or increasing watershed imperviousness. Cumulative
effects on riparian areas of smaller streams include increased discharge volumes and velocities
of water, which then result in more severe downstream flooding and increased storm damage or
maintenance to existing structures, including dams. Information on techniques to mitigate
effects on smaller streams can is also in the Urban chapter of this guidance (Chapter 3).
Design Guidance and Additional Information
The Iowa Department of Natural Resources (no date) recommends that the property owner or
developer estimate the amount of time, materials, equipment, and labor necessary to complete
the work as compared to those personally available. This is a subjective decision based on time,
knowledge, and resource constraints.
• Construction activities should be conducted during periods of low flow.
• Construction equipment, activities, and materials should be kept out of the water to the
maximum extent possible.
• All construction debris should be disposed of on land in such a manner that it cannot
enter a waterway or wetland.
7-66
Chapter 7. Hydromodification
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
• Equipment for handling and conveying materials during construction should be operated
to prevent dumping or spilling the material into waterbodies, streams, or wetlands.
• Care should be taken to prevent any petroleum products, chemicals, or other deleterious
materials from entering waterbodies, streams, or wetlands.
• Clearing of vegetation, including trees in or immediately adjacent to waters of the state,
should be limited to that which is absolutely necessary for construction of the project. All
vegetative clearing material should be removed to an upland, non-wetland disposal site.
Each of the methods described in the manual requires observation and maintenance of the
streambank erosion control practices over time. Observations should be made regularly before
and after major stream flow events. Maintenance activities should include the following:
• Remove any debris that becomes entangled in the erosion control material and could
damage the bank materials.
• Replace missing or damaged erosion control materials during times of low stream flow.
• Apply fertilizer to plant materials to enhance their growth each year.
• Apply fertilizer and weed control to buffer strip vegetation.
• Restrict livestock from steep banks and the areas containing the erosion control
measures.
Riparian Buffers
Riparian buffers are described in Chapter 5 of this document.
Chapter 7. Hydromodification 7-67
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
3.2.19 Riprap
Description
Riprap is a layer of appropriately sized stones designed
to protect and stabilize areas subject to erosion, slopes
subject to seepage, or areas with poor soil structure.
Application and Purpose
0 Protect Streambanks and
Shorelines from Erosion
D Control Upland Sources of
Sediment and Nutrients at Dams
D Restore In-stream and Riparian
Habitat Function
D Reduce Pollutant Sources
through Operational and Design
Management
The National Management Measures to Control
Nonpoint Sources Pollution from Hydromodification
document (USEPA 2007) has a chapter on the practice
of riprap. At the time of this writing, no additional
information is provided pertaining to the practice. For
information on the appropriate use and application for riprap, see the 2007 guide.
D Restore Stream and Shoreline
Physical Characteristics
Cost Data
Riprap costs vary depending on the class of riprap, the location of the quarry, and installation
practices. Prices typically range from $40 to $70 per ton.
7-68
Chapter 7. Hydromodification
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
3.2.20 Rock and Log Vanes
Description
Rock and log vanes are single-arm structures that are D Protect Streambanks and
.... . . . . . .. . . . ...... Shorelines from Erosion
partially embedded in the streambed such that they are
submerged even during ,ow flows. D S±SSS 2
D Restore In-stream and Riparian
Habitat Function
Application and Purpose _ D . 0 „ . . 0
'' ' D Reduce Pollutant Sources
Rock and log vanes induce secondary circulation of the
flow, thereby promoting the development of scour „
0 Restore Stream and Shoreline
pools. Vanes can also be paired and positioned in a Physical Characteristics
channel reach to initiate meander development or
migration. They essentially mimic the effect of a tree
partially falling into the stream. They are usually placed along the streambank where erosion is
occurring along the toe of the slope. The purpose of vanes is to reduce erosion along the
streambank by redirecting the stream flow toward the center of the stream. In addition, they tend
to create scour pools on the downstream side.
Vanes can be made of rock or log. They grade down from the bankfull elevation at the
streambank to the channel invert at their terminus in the stream. Vanes generally extend out
from the streambank one-third of the bankfull width and are angled upstream from the bank at a
20 to 30 degree angle. They should be carefully located and installed so as not to produce
additional erosion on the upstream side where they meet the bank (eddy scour) or allow flows to
outflank them, exacerbating existing bank erosion problems. The only difference between the
log vane and the rock vane is the material used. The J-hook vane is basically the same as a
rock vane with the exception that it curls around at the end in the shape of a "J." The curved end
portion serves to enhance downstream scour pool formation.
The following limitations apply to vanes:
• Vanes should not be used in unstable streams unless measures have been taken to
promote stream stability so that it can retain a constant planform and dimension without
signs of migration or incision.
• Vanes are ineffective in bedrock channels because minimal bed scouring occurs.
Conversely, streams with fine sand, silt, or otherwise unstable substrate should be
avoided because significant undercutting can destroy these measures.
• Vanes should not be used in stream reaches that exceed a 3 percent gradient.
Chapter 7. Hydromodification 7-69
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
• Vanes should not be used in streams with large sediment or debris loads.
• Banks opposite the structures should be monitored for excessive erosion.
Cost Data
Rock and log vanes vary greatly in cost depending on the design, availability and selection of
materials, and site conditions.
Design Guidance and Additional Information
The following documents provide design information and guidance for vanes.
Stream Restoration: A Natural Channel Design Handbook, prepared by the North Carolina
Stream Restoration Institute and North Carolina Sea Grant.
http://www.bae.ncsu.edu/programs/extension/wqg/srp/sr guidebook.pdf
The Virginia Stream Restoration & Stabilization Best Management Practices Guide. Department
of Conservation and Recreation, Division of Soil and Water Conservation. 2004.
http://www.dcr.virginia.gov/soil and water/documents/streamguide.pdf
7-70 Chapter 7. Hydromodification
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
3.2.21 Selective Withdrawal
Description
Selective withdrawal describes the use of intake D Protect Streambanks and
,, , , , . Shorelines from Erosion
structures on reservoirs that are capable of releasing
waters from specific iocations within a stratified water D 'SSXXZXfXEZ a! Dams
column to address downstream water quality _ _ . , . . _. .
D Restore In-stream and Riparian
Objectives. Habitat Function
0 Reduce Pollutant Sources
through Operational and Design
Application and Purpose Management
D Restore Stream and Shoreline
Selective withdrawal in reservoir releases depends on Physical Characteristics
the volume of water storage in the reservoir, the timing . ,
of the release relative to storage time, and the level
from which the water is withdrawn. Selective withdrawal takes advantage of the phenomenon of
reservoir stratification, in which the water column exhibits various quality characteristics
respective to water depth. Multilevel intake devices in storage reservoirs allow selective
withdrawal of water according to temperature, dissolved oxygen levels or other stratified water
quality characteristics. They can be particularly useful in stratified reservoirs so that they can be
operated to meet downstream water quality objectives such as to maintain downstream
temperature conditions or minimize the turbidity of discharge waters. While most selective
withdrawal intakes structures are built during initial reservoir construction, release structures can
be successfully modified to incorporate selective withdrawal as a retrofit, although doing so
could be costly.
Chapter 7. Hydromodification 7-71
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
3.2.22 Shoreline Sensitivity Assessment
Description
Shoreline sensitivity assessments are methodologies
that apply to shoreline areas and are used to evaluate,
classify, and assess stability and erosion vulnerabilities
in various types of lakes, reservoirs, estuaries, and
coasts.
Application and Purpose
n Protect Streambanks and
Shorelines from Erosion
D Control Upland Sources of
Sediment and Nutrients at Dams
0 Restore In-stream and Riparian
Habitat Function
D Reduce Pollutant Sources
through Operational and Design
Management
D Restore Stream and Shoreline
Physical Characteristics
(Langendoen et al. 2009) found that restoration
projects could benefit from using proven models of
stream and riparian processes to guide restoration
design and to evaluate indicators of ecological integrity. The USDA has developed two such
models: the channel evolution computer model (CONCEPTS) and REMM.
Efficiency Data
The physical process modules of the channel evolution model CONCEPTS and the riparian
ecosystem model REMM have been integrated to create a comprehensive stream-riparian
corridor model that will be used to evaluate the effects of riparian buffer systems on in-stream
environmental resources (Langendoen et al. 2009). The models have been integrated to
evaluate the impact of edge-of-field and riparian conservation measures on stream morphology
and water quality. The capability of REMM to dynamically simulate streambank hydrology and
plant growth has been used to study the effectiveness of a deciduous tree stand and an eastern
gamagrass buffer in controlling the stability of a streambank of an incised stream in northern
Mississippi.
7-72
Chapter 7. Hydromodification
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
3.2.23 Step Pools
Description
Step pools are rock grade-control structures D Protect Streambanks and
....... . . .. . . . , Shorelines from Erosion
constructed in the stream channel that recreate natural
step-poo, channe, morphoiogy. D %5£££S5£Z °a! Dams
D Restore In-stream and Riparian
Habitat Function
Application and Purpose Q Reduce po||utgnt Sources
Step-pool channels are characterized by a succession
of channel-spanning steps formed by large, grouped _ „ „ , „, ,.
K * ^ a a , a K 0 Restore stream and Shoreline
boulders called clasts that separate pools containing Physical Characteristics
finer bed sediments. They are constructed in higher
gradient channels where a fixed-bed elevation is
required. Step pools are built in series and allow for stepping down the channel over a series of
drops. The steps are constructed of large rock with the pools containing smaller rock material.
As flow tumbles over the step, energy is dissipated into the plunge pool.
Step-pools can be used to backwater a culvert, providing improved fish passage and can be
used to connect two reaches with different elevations.
Step-pool morphologies are typically associated with well-confined, high-gradient channels with
slopes greater than 3 percent, having small width-depth ratios and bed material dominated by
cobbles and boulders. Step pools generally function as grade-control structures and aquatic
habitat features by reducing channel gradients and promoting flow diversity. At slopes greater
than roughly 6.5 percent, similar morphologic units termed cascades spanning only a portion of
the channel width are formed in these channel conditions.
Step pools are not generally considered a habitat enhancement practice. The enhancement
potential is in the form of maintaining fish passage and expanding the total amount of habitat
available for fish.
Cost Data
Construction costs for step pools are highly variable, depending on the design, size of the stone,
availability of materials, and site constraints.
Chapter 7. Hydromodification 7-73
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
Design Guidance and Additional Information
The following documents provide design information and guidance for vanes.
Stream Restoration: A Natural Channel Design Handbook, prepared by the North Carolina
Stream Restoration Institute and North Carolina Sea Grant.
http://www.bae.ncsu.edu/programs/extension/wqg/srp/sr guidebook.pdf
The Virginia Stream Restoration & Stabilization Best Management Practices Guide, Department
of Conservation and Recreation, Division of Soil and Water Conservation 2004.
http://www.dcr.virginia.gov/soil and water/documents/streamguide.pdf
7-74 Chapter 7. Hydromodification
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
3.2.24 Streambank Dewatering
Description
Streambank dewatering is the practice of using 0 Protect Streambanks and
,. , , ,. Shorelines from Erosion
groundwater level management adjacent to an eroding
Streambank to lower static water pressure on bank and D S^a^e^ 2 Dams
reduce erosion potential. _ _ . , . . _. .
D Restore In-stream and Riparian
Habitat Function
. D Reduce Pollutant Sources
Application and Purpose through Operational and Design
Management
Streambank dewatering is the practice of actively or _ „ „
0 Restore Stream and Shoreline
passively reducing the static water level immediately Physical Characteristics
adjacent to a Streambank with erosion potential for the . ,
purposes of reducing poor water pressure within the
Streambank. The reduced pore pressure improves the shear strength of bank soils. Because
shear strength is one of several governing factors for bank failure, a reduction in bank failure
rates and potential is expected.
Dewatering systems can take several forms. Specific designs that are discussed in the research
literature are vertical groundwater wells managed by an active pumping system and installing
horizontal tile drains, which provide passive drainage for the riparian zone. While other
dewatering system designs might be possible, no published information on additional methods
are available. The location, depth, capacity, and configuration of the dewatering systems vary
depending on local conditions, and no published guidance on Streambank dewatering is
available.
Using Streambank dewatering is not widespread. A number of alternative practices are available
that might be more suitable for a particular application. Dewatering systems that rely on
pumping systems have an inherent long-term maintenance and operational cost. For those
reasons, Streambank dewatering might be most appropriate for short-term use or in areas
where grading and practice installation along the bank are not possible (such as because of
utility conflicts, access constraints, and the like). In addition, it is important to note that
Streambank dewatering can affect riparian habitat condition and available groundwater for
riparian habitat. Where wetlands are present adjacent to the stream, dewatering could affect the
wetland condition.
Chapter 7. Hydromodification 7-75
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
Performance
Shields et al. (2009) reported that streambank dewatering resulted in reduced rates of bank
erosion on a deeply incised channel in northern Mississippi. Pumped and passive drain systems
exhibited bank erosion of 0.21 m and 0.23 m, respectively, over a 2-year period of two wet
seasons, while a streambank without dewatering exhibited erosion of 0.43 m. While reduced
bank erosion was observed where streambank dewatering was used, the researches note that
at some individual monitoring stations, bank erosion exceeded control values.
Cost Effectiveness
While no published cost information is available, Shields et al. (2009) report that initial costs of
dewatering systems was significantly lower than more orthodox bank stabilization measures,
while it was acknowledged that long term pumping and maintenance costs were neglected.
7-76 Chapter 7. Hydromodification
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
3.2.25 Toe Protection
Description
Toe protection refers to the installation of erosion
resistant material, typically stone, near and at the water
line along shorelines and streams to reduce wave
reflection and scour of the land water interface.
Application and Purpose
The purpose of toe protection is to dissipate wave and
scour energy at the land water interface of and
therefore reduce shoreline and streambank erosion.
0 Protect Streambanks and
Shorelines from Erosion
D Control Upland Sources of
Sediment and Nutrients at Dams
D Restore In-stream and Riparian
Habitat Function
D Reduce Pollutant Sources
through Operational and Design
Management
D Restore Stream and Shoreline
Physical Characteristics
The National Management Measures to Control Nonpoint Sources Pollution from
Hydromodification document (USEPA 2007) provides information on the use of toe protection to
reduce shoreline erosion. While the installation techniques and methods differ slightly where toe
protection is used to reduce streambank erosion, the practice is principally the same.
Efficiency Data
Efficiency data on toe protection in streambanks is limited. However, recent research projects
have shown reduced loss of streambank where toe protection is implemented on eroding
channels. A modeling study in the Lake Tahoe basin using the Bank-Stability and Toe-Erosion
Model (BSTEM) predicted that the application of a 1.0-m-high rock toe protection would reduce
bank erosion by 69-100 percent (Simon et al. 2009). It was further noted that only 14 percent of
the sediment loss in the streambank of the studied reach was from the toe region, the remaining
sediment loss resulted from mass wasting of the overlying streambank indicating the importance
of the land water interface in overall stream sediment dynamics.
Chapter 7. Hydromodification
7-77
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
3.2.26 Turbine Operation
Description
Turbine operations include implementing changes in
the turbine start-up procedures that can enlarge the
zone of withdrawal to include more of the epilimnetic
waters in the downstream releases.
Application and Purpose
In an improvement effort that included changes in
turbine operation, the TVA made operational changes
and installed additional equipment to ensure that
minimum water flows through its dams.
D Protect Streambanks and
Shorelines from Erosion
D Control Upland Sources of
Sediment and Nutrients at Dams
D Restore In-stream and Riparian
Habitat Function
0 Reduce Pollutant Sources
through Operational and Design
Management
D Restore Stream and Shoreline
Physical Characteristics
Cost Data
Since the early 1990s, the TVA has spent about $60 million to address dissolved oxygen
problems below dams, including turbine operation.
Reference
Tennessee Valley Authority. No date. Tailwater Improvements: Improving Water Quality Below
TVA Hydropower Dams.
7-78
Chapter 7. Hydromodification
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
3.2.27 Turbine Venting
Description
Turbine venting is the practice of injecting air into water
as it passes through a turbine. If vents are inside the
turbine chamber, the turbine will aspirate air from the
atmosphere and mix it with water passing through the
turbine as part of its normal operation. Autoventing
turbines are constructed with hub baffles or deflector
plates placed on the turbine hub upstream of the vent
holes to enhance the low-pressure zone in the vicinity
of the vent and thereby increase the amount of air
aspirated through the venting system.
D Protect Streambanks and
Shorelines from Erosion
D Control Upland Sources of
Sediment and Nutrients at Dams
D Restore In-stream and Riparian
Habitat Function
0 Reduce Pollutant Sources
through Operational and Design
Management
D Restore Stream and Shoreline
Physical Characteristics
Application and Purpose
Developments in turbine venting technology show potential for aspirating air with no resulting
decrease in turbine efficiency. However, applying turbine venting technologies is site-specific,
and outcomes will vary considerably.
Efficiency Data
Turbine efficiency relates to the amount of energy output from a turbine per unit of water
passing through the turbine. Efficiency decreases as less power is produced for the same
volume of water. In systems where the water is aerated before passing through the turbine, part
of the water volume is displaced by the air, thus leading to decreased efficiency.
Chapter 7. Hydromodification
7-79
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
3.2.28 Vegetated Buffers
Description
Vegetated buffers are naturally occurring, composed of
vegetative areas that provide physical separation
between a waterbody and adjacent land uses.
Application and Purpose
Vegetated buffers remove nutrients and other
pollutants from runoff, trap sediments, and shade the
waterbody to optimize light and temperature conditions
for aquatic plants and animals.
D Protect Streambanks and
Shorelines from Erosion
D Control Upland Sources of
Sediment and Nutrients at Dams
0 Restore In-stream and Riparian
Habitat Function
D Reduce Pollutant Sources
through Operational and Design
Management
D Restore Stream and Shoreline
Physical Characteristics
Efficiency Data
Protecting or restoring modest-sized patches of living shoreline can provide adequate prime
waterfowl habitat (Blankenship 2009). Hail Creek, a tiny waterway at the tip of a peninsula that
is separated by a narrow swath of land from the Chester River, is shorter than a half-mile long.
But, despite its diminutive size, the creek and its surrounding marshes, part of the Eastern Neck
National Wildlife Refuge, are one of the top five waterfowl habitats in Maryland, with large
concentrations of bufflehead and scaup, as well as black ducks, Canada geese, and other
species. The creek has about 100 acres of underwater grasses, in contrast with nearby areas
where grasses have been declining. Those habitats have faced increasing danger in recent
years from rising water levels that have been eating away at a narrow barrier of land that
separates the upstream end of the creek from Hail Cove along the Chester River. If breached,
the sheltered creek habitats and adjoining wetlands would suddenly be subjected to highly
erosive waves.
Besides the living shoreline, curved rock structures were built at both ends of the cove to protect
it from waves and to trap sand that serves as beach habitat. The project included constructing
an oyster reef, which serves as habitat and buffers the shoreline from waves. Shallow water
habitats, which had largely eroded away, were rebuilt and planted with marsh grasses.
Reestablishing shallow water habitat, including oyster beds and mussel beds, will serve as
foraging grounds for sea ducks, which should keep Hail Creek as one of the top five waterfowl
habitats for years to come.
7-80
Chapter 7. Hydromodification
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
Cost Data
A partnership involving more than a dozen organizations, agencies, and businesses joined
forces to construct an 800-foot living shoreline. They rebuilt the barrier between the creek and
the cove with natural materials, which was then planted with native plants to provide more
stability. The project relied on volunteers and multiple funders and was the first project in the
Chesapeake that involved the Corporate Wetland Restoration Partnership, which brings
together government on environmental projects. This type of restoration project was envisioned
in the draft habitat report that responded to President Barack Obama's Executive Order of May
2009 that calls for using partnerships to build strategically placed "largescale, multifaceted
restoration [projects] targeted at improving living resources."
Chapter 7. Hydromodification 7-81
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
3.2.29 Vegetated Filter Strips
Description
Vegetated filter strips are low-gradient vegetated areas D Protect Streambanks and
Shorelines from Erosion
that filter overland sheet flow. Runoff must be evenly
distributed across the filter strip, and channelized flows D ^'eK^SS 2 Dams
decrease their effectiveness. _ _ . , . . _. .
0 Restore In-stream and Riparian
Habitat Function
. D Reduce Pollutant Sources
Application and Purpose through Operational and Design
Management
Vegetated filter strips should have relatively low slopes ,_, „ „
D Restore Stream and Shoreline
and adequate length to provide optimal sediment Physical Characteristics
control and should be planted with erosion-resistant . ,
plant species. The main factors that influence the
removal efficiency are the vegetation type, soil infiltration rate, and flow depth and travel time.
Such factors are dependent on the contributing drainage area, slope of strip, degree and type of
vegetative cover, and strip length. Maintenance requirements for vegetated filter strips include
sediment removal and inspections to ensure that dense, vigorous vegetation is established, and
concentrated flows do not occur.
Efficiency Data
A study of cost-effectiveness analysis of vegetative filter strips and in-stream half-logs as tools
for recovering scores on a fish IBI in the upper Wabash River in Indiana provided baseline data
and a framework for planning and determining the cost of stream restoration (Frimpong et al.
2006). Three assumptions were made about recovery time for IBI scores (5, 15, and 30 years)
and social discount rates (1, 3, and 5 percent), which were tested for sensitivity of the estimated
cost-effectiveness ratios. The effectiveness of vegetative filter strips was estimated using fish
I Bis and riparian forest cover from 49 first-order to fifth-order stream reaches. Half-log structures
had been installed for approximately 2 years in the watershed before the study and provided a
basis for estimates of cost and maintenance.
Cost Data
Frimpong et al. (2006) found that costs per unit increase in IBI score with vegetative filter strips
as the method of restoring stream health decreases with increasing stream order and
decreasing recovery time. Another finding of this study was that vegetative filter strips is likely a
useful method, given cost considerations, for recovering lost IBI scores in an agricultural
7-82 Chapter 7. Hydromodification
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
watershed. Cost-effectiveness ratios for vegetated filter strips decreased from $387 to $277 per
100 meters for a 1 percent increase in IBI scores from first- to fifth-order streams with 3 percent
discount and 30-year recovery. That cost, weighted by proportion of stream orders was $360
per 110 meters. On the basis of installation costs and an assumption of equal recovery rates,
half-logs were two-thirds to one-half as cost-effective as vegetative filter strips. Half-logs would
be a cost-effective supplement to filter strips in low-order streams if they can be proven to
recover IBI scores faster than using filter strips alone.
Chapter 7. Hydromodification 7-83
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
3.2.30 Vegetated Gabions
Description
A gabion is a rectangular basket made of heavily
galvanized wire mesh filled with small to medium size
rock. The gabions are laced together and installed at
the base of a bank to form a structural toe or sidewalk
Vegetation can be incorporated by placing live
branches between each layer of rock filled baskets.
The branches take root inside the gabions and in the
soil behind the structures. Their roots eventually
consolidate the structure and bind it to the slope.
0 Protect Streambanks and
Shorelines from Erosion
D Control Upland Sources of
Sediment and Nutrients at Dams
D Restore In-stream and Riparian
Habitat Function
D Reduce Pollutant Sources
through Operational and Design
Management
0 Restore Stream and Shoreline
Physical Characteristics
Application and Purpose
The National Management Measures to Control Nonpoint Sources Pollution from
Hydromodification document (USEPA 2007) contains a chapter on the practice of vegetated
gabions. At the time of this writing, no additional information is provided pertaining to this
practice. For information on the appropriate use and application for vegetated gabions, see the
2007 guide.
Cost Effectiveness
Vegetated gabions are comparable to vegetated geogrids and vegetated reinforced soil slope,
ranging from $15 to $40 per square foot. Construction costs vary with the structure's design
(materials, depth into the streambed, height and width, and such), site access, time of year,
degree and type of associated channel redefinition, and equipment and labor rates.
7-84
Chapter 7. Hydromodification
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
3.2.31 Vegetated Geogrids
Description
Vegetated geogrids are the covering of soil with
erosion control fabric (geotextile) on the slope of the
bank. The erosion control fabric is secured by tucking it
into the slope. Live cuttings are placed between the
geogrids, and a root structure is established to bind the
soil within and behind the geogrids. The toe of the bank
is stabilized by layers of rock on top of the same
geotextile fabric.
Application and Purpose
0 Protect Streambanks and
Shorelines from Erosion
D Control Upland Sources of
Sediment and Nutrients at Dams
D Restore In-stream and Riparian
Habitat Function
D Reduce Pollutant Sources
through Operational and Design
Management
0 Restore Stream and Shoreline
Physical Characteristics
The National Management Measures to Control Nonpoint Sources Pollution from
Hydromodification document (USEPA 2007) has a chapter on the practice of Vegetated
Geogrids. At the time of this writing, no additional information is provided pertaining to this
practice. For information on the appropriate use and application for vegetated geogrids, see the
2007 guide.
Cost Data
Vegetated geogrids range in cost from $20 to $40 per square foot depending on the design and
construction techniques (Sotir and Fischenich 2003).
Chapter 7. Hydromodification
7-85
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
3.2.32 Vegetated Reinforced Soil Slope (VRSS)
Description
The vegetated reinforced soil slope (VRSS) soil system 0 Protect Streambanks and
, , , ,. ,. . Shorelines from Erosion
is an earthen structure constructed from living,
rootabie, live-cut, woody p!ant malaria! branches, bare D ZSXXZXfXEZ a! Dams
root, tubling or container plant stock, along with rock, _ _ . , . . _. .
D Restore In-stream and Riparian
geosynthetics, geogrids, and/or geocomposites. Habitat Function
D Reduce Pollutant Sources
through Operational and Design
Application and Purpose Management
0 Restore Stream and Shoreline
The National Management Measures to Control Physical Characteristics
Nonpoint Sources Pollution from Hydromodification
document (USEPA 2007) has a chapter on the practice
of Vegetated Reinforced Soil Slopes. At the time of this writing, no additional information is
provided pertaining to this practice. For information on the appropriate use and application for
vegetated reinforced soil slopes, see the 2007 guide.
Cost Data
Vegetated reinforced soil slopes structure costs typically range from $15 to $35 per square face
foot. These prices do not include design, which can be extensive because of the required
geotechnical data collection and analysis. Harvesting, transportation, handling, and storage of
the live-cut branch materials or rooted plants can significantly influence cost, and are included in
the above range.
Construction costs also vary with the structure's design (materials, depth into the streambed,
height and width, and such), site access, time of year, degree and type of associated channel
redefinition, and equipment and labor rates. Installation is relatively complex because it can
require large earth-moving machinery. Installation, excavation, and soil replacement costs are
usually high.
7-86 Chapter 7. Hydromodification
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
3.2.33 Weirs
Description
This is a technique in which boulders or logs are laced n Protect Streambanks and
... , . . . . .. . i ,_ i Shorelines from Erosion
across the channel and anchored to the channel bank
or bed (or both) to check the water ahd raise its level D 'SSXXZXfXEZ a! Dams
for diversion purposes; they are designed to allow _ _ . , . . _. .
D Restore In-stream and Riparian
overtopping. Habitat Function
D Reduce Pollutant Sources
through Operational and Design
Application and Purpose Management
0 Restore Stream and Shoreline
Low-profile, in-stream structures such as vortex rock Physical Characteristics
weirs and w-weirs are primarily used to create aquatic . ,
habitat in the form of scour pools and for grade control
on incising streams and rivers. Additionally, they are well-suited for channeling flow away from
unstable banks. Weirs are used to collect and retain gravel for spawning habitat, to deepen
existing resting/jumping pools; to create new pools above or below the structure, to trap
sediment, to aerate the water, and to promote deposition of organic debris.
There are several types of weirs, but the two most common types for stream restoration are the
W-weir and the rock vortex weir. Both types provide grade control and reduce bank erosion. The
weirs accumulate sediment behind the weir arms and create a scour pool downstream of the
structure. A rock W-weir is a stone structure composed of footer and vane rocks and consists of
four weir arms arranged in a Wfashion across the channel. A rock vortex weir consists of footer
and vane rocks, and the form of the rock vortex weir is parabolic and spans the channel width.
The rock vortex weir accumulates sediment behind the weir arms and creates a scour pool
downstream of the structure.
Weirs are typically suited for use in moderate to high gradient streams. W-weirs are best used in
rivers with bankfull widths greater than 40 feet (12 meters). Weirs should be avoided in
channels with bedrock beds or unstable bed substrates, and streams with naturally well-
developed, pool-riffle sequences.
Cost Data
Construction costs for weirs are highly variable, depending on width of the channel, size of the
stone, availability of materials, and site constraints.
Chapter 7. Hydromodification 7-87
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
Design Guidance and Additional Information
The following document provides design information and guidance for vanes.
Stream Restoration: A Natural Channel Design Handbook, prepared by the North Carolina
Stream Restoration Institute and North Carolina Sea Grant.
http://www.bae.ncsu.edu/programs/extension/wqg/srp/sr guidebook.pdf
7-88 Chapter 7. Hydromodification
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
3.2.34 Wing Deflectors
Description
Wing deflectors are devices made of a variety of D Protect Streambanks and
...... . . . .-... . , r Shorelines from Erosion
materials that project outward into the channel from
one or both Streambanks but do not extend entirely D 'SSXXZXfXEZ a! Dams
across the channel. Wing deflectors are especially _ _ . , . . _. .
D Restore In-stream and Riparian
effective in wide, shallow, low gradient streams to Habitat Function
create pools and cover. n Reduce Pollutant Sources
through Operational and Design
Management
Application and Purpose 0 Restore Stream and Shoreline
Physical Characteristics
Wing deflectors are designed to deflect flows away . ,
from the bank and create scour pools by constricting
the channel and accelerating flow. The structures can be installed in series on alternative
Streambanks to produce a meandering thalweg and stream diversity. The most common design
is a rock and rock-filled log crib deflector structure. The design bases the size of the structure on
anticipated scour. These structures need to be installed far enough downstream from riffle areas
to avoid backwater effects that could drown out or damage the riffle. This design should be
employed in streams with low physical habitat diversity, particularly channels that lack pool
habitats. Construction on a sand bed stream can be susceptible to failure and should be
constructed with the use a filter layer or geotextile fabric beneath the wing deflector structure
(FISRWG 1998).
When two wing deflectors are placed opposite each other they serve to narrow or constrict the
flow of water. The double wing deflector is more often used in urban applications as it forces the
water toward the center of the channel and deepens the baseflow channel. Double wing
deflectors also create an area of increased velocity between them, enhancing riffle habitat
between and just upstream of the structure. This increased velocity also creates an area of
scour, creating pool habitat downstream of the structure. The construction is the same as a
single wing deflector except that in some instances, a rock sill at the stream invert can connect
the two structures.
Both single and double wing deflectors have significant habitat enhancement potential. These
structures enhance habitat through pool formation, the narrowing and deepening of the
baseflow channel, and the enhancement of riffle habitat. Deflectors protect the bank in the
immediate area and provide desirable changes to the stream flow patterns. They are relatively
easy to construct, inexpensive, easily modified to suit on-site conditions, and are adaptable for
Chapter 7. Hydromodification 7-89
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
use with other treatments. They are significantly cheaper to install than dam-type structures.
They are effective in sections of streams where the banks are too low or too wide for dams.
The following limitations apply to stream deflectors:
• Deflectors should not be used in unstable streams that do not retain a constant planform
or are actively incising at a moderate to high rate.
• Deflectors are ineffective in bedrock channels because minimal bed scouring occurs.
Conversely, streams with fine sand, silt, or otherwise unstable substrate should be
avoided because significant undercutting can destroy the measures.
• Deflectors should not be used in stream reaches that exceed a 3 percent gradient.
• Deflectors should not be used in streams with large sediment or debris loads.
• Banks opposite these structures should be monitored for excessive erosion.
Design Guidance and Additional Information
Additional Resources
FISRWG (Federal Interagency Stream Restoration Working Group). 1998. Stream Corridor
Restoration: Principles, Processes, and Practices. Federal Interagency Stream
Restoration Working Group.
http://www.nrcs.usda.gov/technical/stream restoration/PDFFILES/APPENDIX.pdf.
Massachusetts DEP. 2006. Massachusetts Nonpoint Source Pollution Management Manual:
Wng Deflectors. Massachusetts Department of Environmental Protection, Boston, MA.
http://proiects.geosyntec.com/NPSManual/Fact%20Sheets/Wng%20Deflectors.pdf.
Mississippi State University, Center for Sustainable Design. 1999. Water Related Best
Management Practices in the Landscape: Single Wng Deflector. Prepared for the U.S.
Department of Agriculture, Natural Resource Conservation Service, Watershed Science
Institute. http://www.abe.msstate.edu/csd/NRCS-BMPs/pdf/streams/bank/singlewing.pdf.
Mississippi State University, Center for Sustainable Design. 1999. Water Related Best
Management Practices in the Landscape: Double Wng Deflector. Prepared for the U.S.
Department of Agriculture, Natural Resource Conservation Service, Watershed Science
Institute. http://abe.msstate.edu/csd/NRCS-BMPs/pdf/streams/bank/doublewing.pdf.
Ohio DNR (Department of Natural Resources). No date. Ohio Stream Management Guide:
Deflectors. Ohio Department of Natural Resources.
http://www.ohiodnr.com/water/pubs/fs st/stfs19.pdf.
7-90 Chapter 7. Hydromodification
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
SMRC (Stormwater Manager's Resource Center). No date. Stream Restoration: Flow
Deflection/Concentration Practices. The Stormwater Manager's Resource Center.
http://www.stormwatercenter.net/Assorted%20Fact%20Sheets/Restoration/flow deflection
.htm.
Chapter 7. Hydromodification 7-91
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
4 References
Ahearn, D.S., R.W. Sheibley, and R. Dalhlgren. 2005. Effects of river regulation on water quality in
the lower Mokelumne River, California. River Research and Applications 21(6):651-670.
Alexander, G.G., and J.D. Allan. 2006. Stream restoration in the Upper Midwest, USA.
Restoration Ecology 14(4):595-604.
Alexander, G.G., and J.D. Allan. 2007. Ecological success in stream restoration: Case studies
from the midwestern United States. Environmental Management 40(2):245-255.
Allen, H., and C. Fischenich. 2000. Coir Geotextile Roll and Wetland Plants for Streambank
Erosion Control. U.S. Army Corps of Engineers, Ecosystem Management and Restoration
Ecosystem Research Program, Vicksburg, MS.
Beechie, T., G. Pess, and P. Roni. 2008. Setting river restoration priorities: a review of
approaches and a general protocol for identifying and prioritizing actions. North American
Journal of Fisheries Management 28(3): 891-905.
Bernhardt, E.S., M.A. Palmer, J.D. Allan, G. Alexander, K. Barnas, S. Brooks, J. Carr, S.
Clayton, C. Dahm, J. Follstad-Shah, D. Galat, S. Gloss, P. Goodwin, D. Hart, B. Hassett,
R. Jenkinson, S. Katz, G.M. Kondolf, P.S. Lake, R. Lave, J.L Meyer, T.K. O'Donnell, L.
Pagano, B. Powell, and E. Sudduth. 2005. Ecology - Synthesizing US river restoration
efforts. Science 308(5722):636-637.
Blankenship, K. 2009. Living shoreline project protects waterfowl habitat. Bay Journal.
Baltimore, MD, Alliance for the Chesapeake Bay. 19:1.
Booth, D.B., J.R. Karr, S. Schauman, C.P. Konrad, S.A. Morley, M.G. Larson, and S.J. Surges.
2004. Reviving urban streams: Land use, hydrology, biology, and human behavior.
Journal of the American Water Resources Association 40(5): 1351-1364.
Born, S.M., K.D. Genskow, T.L. Filbert, N. Hernandez-Mora, M.L Keeferand K.A. White. 1998.
Socioeconomic and institutional dimensions of dam removals: the Wisconsin experience.
Environ Mgt 22:359-70.
Brussock, P.P., A.V. Brown, and J.C. Dixon. 1985. Channel form and stream ecosystem
models. Water Resources Bulletin 21:859-866.
Bukaveckas, P.A. 2007. Effects of channel restoration on water velocity, transient storage, and
nutrient uptake in a channelized stream. Environmental Science & Technology
41 (5): 1570-1576.
7-92 Chapter 7. Hydromodification
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
Bushaw-Newton, K.L., D.D. Hart, J.E. Pizzuto, J.R. Thomson, J. Egan, J.T. Ashley, I.E.
Johnson, R.J. Horwitz, M. Keeley, J. Lawrence, D. Charles, C. Gatenby, D.A. Kreeger, T.
Nightengale, R.L. Thomas, and D.J. Velinsky. 2002. An integrative approach towards
understanding ecological responses to dam removal: The Manatawny Creek Study.
Journal of the American Water Resources Association 38(6):1581-1599.
Chang, H.H. 2008. Case study of fluvial modeling of river responses to dam removal. Journal of
Hydraulic Engineering-ASCE 134(3):295-302.
Charbonneau, R., and V.H. Resh. 1992. Strawberry creek on the University of California,
Berkeley campus: A case history of urban stream restoration. Aquatic Conservation:
Marine and Freshwater Ecosystems 2(4):293-307.
Chesapeake Bay Program. 2009. Bay Barometer: A Health and Restoration Assessment of the
Chesapeake Bay and Watershed in 2008. EPA-903-R-09-001. Chesapeake Bay Program,
Annapolis, MD.
D'Angelo, D.J., S.V. Gregory, L.R. Ashkenas, and J.L. Meyer. 1997. Physical and biological
linkages within a stream geomorphic hierarchy: a modeling approach. N. Am. Benthol.
Soc. 16(3):480-502.
Doyle, M.W., E.H. Stanley, and J.M. Harbor. 2003. Hydrogeomorphic controls on phosphorus
retention in streams. Water Resources Research 39(6).
Doyle, M.W., E.H. Stanley, C.H. Orr, A.R. Selle, S.A. Sethi, and J.M. Harbor. 2005. Stream
ecosystem response to small dam removal: Lessons from the Heartland. Geomorphology
71(1-2):227-244.
FISRWG (Federal Interagency Stream Restoration Working Group). 1998. Stream Corridor
Restoration: Principles, Processes, and Practices. GPO Item No. 0120-A; SuDocs No. A
57.6/2:EN 3/PT.653. Federal Interagency Stream Restoration Working Group.
Frimpong, E.A., J.G. Lee, and T.M. Sutton. 2006. Cost effectiveness of vegetative filter strips
and instream half-logs for ecological restoration. Journal of the American Water
Resources Association 42(5): 1349-1361.
Frissell, C.A., W.J. Liss, C.E. Warren, and M.D. Hurley. 1986. A hierarchical framework for
stream habitat classification: viewing streams in a watershed context. Environmental
Management ^ 0:199- 214.
Gillilan, S., K. Boyd, T. Hoitsma, and M. Kauffman. 2005. Challenges in developing and
implementing ecological standards for geomorphic river restoration projects: a
practitioner's response to Palmer et al. 2005. Journal of Applied Ecology 42(2):223-227.
Chapter 7. Hydromodification 7-93
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
Graf, W.L. 2006. Downstream hydrologic and geomorphic effects of large dams on American
rivers. Geomorphology 79(3^):336-360.
Gray, D.H., and R.B. Sotir. 1996. Biotechnical Soil Bioengineering Slope Stabilization: A
Practical Guide for Erosion Control. John Wiley and Sons, New York, NY.
Harrison, J.A., R.J. Maranger, R.B. Alexander, A.E. Giblin, P.A. Jacinthe, E. Mayorga, S.P.
Seitzinger, D.J. Sobota, and W.M. Wollheim. 2009. The regional and global significance of
nitrogen removal in lakes and reservoirs. Biogeochemistry 93(1-2): 143-157.
Hassett, B., M. Palmer, E. Bernhardt, S. Smith, J. Carr, and D. Hart. 2005. Restoring
watersheds project by project: trends in Chesapeake Bay tributary restoration. Frontiers in
Ecology and the Environment 3(5):259-267.
Hassett, B.A., M.A. Palmer, and E.S. Bernhardt. 2007. Evaluating stream restoration in the
Chesapeake Bay watershed through practitioner interviews. Restoration Ecology
15(3):563-572.
He, Z.G., W.M. Wu, F.D. Shields Jr. 2009. Numerical analysis of effects of large wood
structures on channel morphology and fish habitat suitability in a Southern U.S. sandy
creek. £co/?ycfro/ogy2(3):370-380.
Hilgartner, W.B., and G.S. Brush. 2006. Prehistoric habitat stability and post-settlement habitat
change in a Chesapeake Bay freshwater tidal wetland, USA. Holocene 16(4):479-494.
Jacobson, R.B., and D.J. Coleman. 1986. Stratigraphy and recent evolution of Maryland
Piedmont flood plains. American Journal of Science 286:617-637.
Jannsson, R., H. Backx, A.J. Boulton, M. Dixon, D. Dugeon, F.M.R. Hughes, K. Nakamura, E.H.
Stanley, and K. Tockner. 2005. Stating mechanisms and refining criteria for ecologically
successful river restoration: a comment on Palmer et al. 2005. Journal of Applied Ecology
42(2):218-222.
Johnson, P.A., and E.R. Brown. 2000. Stream assessment for multicell culvert use. Journal of
Hydraulic Engineering, ASCE, 381-386.
Kaushal, S.S., P.M. Groffman, P.M. Mayer, E. Striz, and A.J. Gold. 2008. Effects of stream
restoration on denitrification in an urbanizing watershed. Ecological Applications
18(3): 789-804.
Klocker, C.A., S.S. Kaushal, P.M. Groffman, P.M. Mayer, and R.P. Morgan. 2009. Nitrogen
uptake and denitrification in restored and unrestored streams in urban Maryland, USA.
Aquatic Sciences 71 (4):411-424.
7-94 Chapter 7. Hydromodification
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
Kondolf, G.M., P.L. Angermeier, K. Cummins, T. Dunne, M. Healey, W. Kimmerer, P.B. Moyle,
D. Murphy, D. Patten, S. Railsback, D.J. Reed, R. Spies, and R. Twiss. 2008. Projecting
Cumulative Benefits of Multiple River Restoration Projects: An Example from the
Sacramento-San Joaquin River System in California. Environmental Management
42(6):933-945.
Kuhnle, R.A., R.L Bingner, C.V. Alonso, C.G. Wilson, and A. Simon. 2008. Conservation
practice effects on sediment load in the Goodwin Creek Experimental Watershed. Journal
of Soil and Water Conservation 63(6):496-503.
Langendoen, E.J., R. R. Lowrance, and A. Simon. 2009. Assessing the impact of riparian
processes on streambank stability. £co/?ycfro/ogy2(3):360-369.
Litvan, M.E., T.W. Stewart, C.L. Pierce and C.J. Larson. 2008. Effects of grade control
structures on the macroinvertebrate assemblage of an agriculturally impacted stream.
River Research and Applications 24(2):218-233.
Martini, E.G., 1998. Wsconsin's Milldam act: drawing new lessons from an old law. Wisconsin
Law Review 1998, 1306-1336.
Merritt, D.M., M.L Scott, N.L. Poff, G.T. Auble, and D.A. Lytle. 2010. Theory, methods and tools
for determining environmental flows for riparian vegetation: riparian vegetation-flow
response guilds. Freshwater 6/o/ogy 55(1):206-225.
Mulholland, P.J., A.M. Helton, G.C. Poole, R.O. Hall, S.K. Hamilton, B.J. Peterson, J.L Tank,
L.R. Ashkenas, L.W. Cooper, and S.L. Johnson. 2008. Stream denitrification across
biomes and its response to anthropogenic nitrate loading. Nature 452(7184):202-205.
Olden, J.D., and R.J. Naiman. 2010. Incorporating thermal regimes into environmental flows
assessments: modifying dam operations to restore freshwater ecosystem integrity.
Freshwater Biology 55(1):86-107.
Palmer, M.A., E.S. Bernhardt, J.D. Allan, P.S. Lake, G. Alexander, S. Brooks, J. Carr, S.
Clayton, C.N. Dahm, J. Follstand Shah, D.L Galat, S.G. Loss, P. Goodwin, D.D. Hart, B.
Hassett, R. Jenkinson, G.M. Kondolf, R. Lave, J.L. Meyer, T.K. O'Donnell, L. Pagano, and
E. Sudduth. 2005. Standards for ecologically successful river restoration. Journal of
Applied Ecology 42(2):208-217.
Pezeshki S.R., S. Li, F.D. Shields Jr., and L.T. Martin. 2007. Factors governing survival of black
willow (Sa//x nigra) cuttings in a field restoration project. Ecological Engineering
29(1):56-65.
Pizzuto, J.E. 2002. Effects of dam removal on river form and process. BioScience 52:683-691.
Chapter 7. Hydromodification 7-95
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
Purcell, A.M., C. Friedrich, and V.H. Resh. 2002. An assessment of a small urban stream
restoration project in northern California. Restoration Ecology 10:685-694.
Roberts, B.J., P.J. Mulholland, and J.N. Houser. 2007. Effects of upland disturbance and
instream restoration on hydrodynamics and ammonium uptake in headwater streams.
Journal of the North American Benthological Society 26(1): 38-53.
Roni, P., K. Hanson, and T. Beechie. 2008. Global review of the physical and biological
effectiveness of stream habitat rehabilitation techniques. North American Journal of
Fisheries Management 28(3):856-890.
Rosgen, D. 1996. Applied River Morphology. Wildland Hydrology, Pagosa Springs, CO.
Schenk, E.R., and C.R. Hupp. 2009. Legacy effects of colonial millponds on floodplain
sedimentation, bank erosion, and channel morphology, Mid-Atlantic, USA. Journal of the
American Water Resources Association 45(3): 597-606.
Schueler, T. 1994. The importance of imperviousness. Center for Watershed Protection. Ellicott
City, M D. Watershed Protection Techniques 1 (3): 1 00 -1 1 1 .
Schwartz, J.S., and E.E. Herricks. 2007. Evaluation of pool-riffle naturalization structures on
habitat complexity and the fish community in an urban Illinois stream. River Research and
Applications 23(4):451-466.
Shields, F.D. Jr., A. Simon, and S.M. Dabney. 2009. Streambank dewatering for increased
stability. Hydrological Processes 23(1 1 ): 1 537-1 547.
Shields, F.D. Jr., N. Morin, C.M. Cooper. 2004. Large woody debris structures for sand-bed
channels. Journal of Hydraulic Engineering 130(3):208-217.
Shields, F.D., R.R. Copeland, P.C. Klingeman, M.W. Doyle, and A. Simon. 2003. Design for
stream restoration. Journal of Hydraulic Engineering-ASCE 129(8):575-584.
Simon, A., N.L. Bankhead, V. Mahacek, and E.J. Langendoen. 2009. Quantifying reductions of
mass-failure frequency and sediment loadings from streambanks using toe protection and
other means: LakeTahoe, USA. Journal of the American Water Resources Association.
Skalak, K., J. Pizzuto, and D.D. Hart. 2009. Influence of small dams on downstream channel
characteristics in Pennsylvania and Maryland: Implications for the long-term geomorphic
effects of dam removal. Journal of the American Water Resources Association
45(1):97-109.
Sotir and Fischenich. 2003. Vegetated Reinforced Soil Slope Streambank Erosion Control.
Engineer Research and Development Center, Vicksburg, MS.
7-96 Chapter 7. Hydromodification
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
Stanley, E.H., and M.W. Doyle. 2002. A geomorphic perspective on nutrient retention following
dam removal. Bioscience 52(8):693-701.
Tennessee Valley Authority. No Date. Tailwater Improvements: Improving Water Quality Below
TVA Hydropower Dams. Tennessee Valley Authority, Knoxville, TN. Accessed February
19,2010.
Urbonas, B.R. 2001. Linking Stormwater BMP Designs and Performance to Receiving Water
Impact Mitigation. In Proceedings of An Engineering Foundation Conference,
Environmental and Water Resources Institute of the American Society of Civil Engineers,
Snowmass Village, CO, August 19-24, 2001.
USDA-FS (U.S. Department of Agriculture-Forest Service). 2002. A Soil Bioengineering Guide
for Streambank and Lakeshore Stabilization. U.S. Department of Agriculture Forest
Service, Technology and Development Program, San Dimas, CA.
USDA-NRCS (U.S. Department of Agriculture-Natural Resources Conservation Service). 1992.
Engineering Field Handbook. U.S. Department of Agriculture, Washington, DC.
USEPA (U.S. Environmental Protection Agency). 2007. National Management Measures to
Control Nonpoint Source Pollution from Hydromodification. EPA 841-B-07-002. U.S.
Environmental Protection Agency, Office of Water, Washington, DC.
USGS (U.S. Geological Survey). 2003. A Summary Report of Sediment Processes in
Chesapeake Bay and Watershed. Water-Resources Investigations Report 03-4123, 2003.
U.S. Geological Survey, Reston, VA.
Valett, H.M., C.L. Crenshaw, and P.F. Wagner. 2002. Stream nutrient uptake, forest succession,
and biogeochemical theory. Ecology 83(10):2888-2901.
Walter, R.C., and D.J. Merritts. 2008. Natural streams and the legacy of water-powered mills.
Science 319(5861):299-304.
Wargo, R.S., and R.N. Weisman. 2006. A comparison of single-cell and multicell culverts for
stream crossings. Journal of the American Water Resources Association 42(4):989-995.
WDNR (Wisconsin Department of Natural Resources). 1995. Wisconsin lakes. Wsconsin
Department of Natural Resources PUBL.-FM-800. Wisconsin Department of Natural
Resources, Madison, Wl.
Wldman, L.A.S., and J.G. MacBroom. 2005. The evolution of gravel bed channels after dam
removal: Case study of the Anaconda and Union City Dam removals. Geomorphology
71(1-2):245-262.
Chapter 7. Hydromodification 7-97
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
Wilson, G.V., F.D. Shields, R.L. Bingner, P. Reid-Rhoades, D.A. DiCarlo, and S.M. Dabney.
2008. Conservation practices and gully erosion contributions in the Topashaw Canal
watershed. Journal of Soil and Water Conservation 63(6):420-429.
Zaimes, G.N., R.C. Schultz, and T.M. Isenhart. 2008. Streambank soil and phosphorus losses
under different riparian land-uses in Iowa. Journal of the American Water Resources
Association 44(4): 935-947.
7-98 Chapter 7. Hydromodification
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
Glossary
activated sludge. Highly concentrated mass of live bacteria that feed on organic wastes, which
are aerated to increase the rate of decomposition.
active/rest cycles (alternating drainfields). Final treatment and soil-based dispersal
component of a decentralized treatment system that is composed of multiple soil treatment
areas, which are independently dosed under the control of a flow diversion valve according to a
preset schedule.
advanced treatment systems. Any treatment of sewage that goes beyond the secondary or
biological water treatment stage and includes the removal of nutrients such as phosphorus and
nitrogen and a high percentage of suspended solids.
aerobic. Having molecular oxygen (O2) as a part of the environment, or a biological process
that occurs only in the presence of molecular oxygen.
aerobic treatment. A process by which microbes decompose complex organic compounds in
the presence of oxygen and use the liberated energy for reproduction and growth. (Such
processes include extended aeration, trickling filtration, and rotating biological contactors.)
aggregate. A collective term for sand, gravel, and crushed stone mineral materials in their
natural or processed state.
allochthonos. Derived from outside a system, such as leaves of terrestrial plants that fall into a
stream.
alluvium. Deposits of clay, silt, sand, gravel, or other particulate material that has been
deposited by a stream or other body of running water in a streambed, on a flood plain, on a
delta, or at the base of a mountain.
alum. A double sulphate formed of aluminum and some other element (esp. an alkali metal) or
of aluminum. It has 24 molecules of water of crystallization. Common alum is the double
sulphate of aluminum and potassium. It is white, transparent, very astringent, and crystallizes
easily in octahedrons. The term is extended so as to include other double sulphates similar to
alum in formula.
Glossary
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
alum (aluminum sulfate) treatment. Alum or aluminum sulfate is an acid that is commonly
used as a poultry litter treatment. Available in either a dry or liquid form, alum's acidic properties
are used to reduce ammonia levels in the poultry house, while its binding properties are used to
reduce phosphorus (P) in runoff (Moore et al. No date). Alum is also used to reduce P losses
from manure and wastewater, to increasing the efficiency of mechanical separation of manure,
and to reduce P losses from grazing land.
ammonia volatilization. A process that commonly takes place when nitrogen is in an organic
form known as urea. Urea can originate from animal manure, urea fertilizers and, to a lesser
degree, the decay of plant materials. Ammonia volatilization is most likely to take place when
soils are moist and warm and the source of urea is on or near the soil surface. Ammonia
volatilization will also take place on alkaline soils (pH greater than 8).
anabranching channel. A distributary channel that departs from the main channel, sometimes
running parallel to it for several kilometers before rejoining it.
anaerobic. Absence of molecular oxygen (O2) as a part of the environment, or a biological
process that occurs in the absence of molecular oxygen; bound oxygen is present in other
molecules, such as nitrate (NO3-) sulfate (SO4+) and carbon dioxide CO2.
anaerobic decomposition. The reduction of the net energy level and change in chemical
composition of organic matter caused by microorganisms in an oxygen-free environment.
analyte. A substance that is undergoing analysis or is being measured.
antidegradation. Provisions in the federal Clean Water Act, codified at 40 CFR 131.12, which
provide (1) a minimum level of protection for all surface waters; (2) requirements for alternatives
analyses, intergovernmental coordination, and social or economic justification before allowing
lowered water quality in high-quality waters; and (3) the highest level of protection for
outstanding national resource waters. State water quality standards must include both an
antidegradation policy and methods for implementation.
applied organic load. The quantity of organic material (e.g., manure) applied to lands or
introduced to a receiving waterbody or treatment practice, typically measured as chemical
oxygen demand (COD) or biological oxygen demand (BOD).
aquifer. A geologic formation, group of formations, or part of a formation that is saturated and
sufficiently permeable to transmit water.
Glossary
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
attenuation. For water velocity: the slowing, modification, or diversion of the flow of water as
with detention and retention ponds. For water quality: the process of diminishing contaminant
concentrations in water because of filtration, biodegradation, dilution, sorption, volatilization, and
other processes.
autoventing turbine. A hydroturbine with pressure-relieving ports that are open to the
atmosphere.
bank shaping. Re-grading streambanks to a stable slope, placing topsoil and other materials
needed for sustaining plant growth, and selecting installing, and establishing appropriate plant
species.
bankfull elevation. The water surface elevation within a channel corresponding to bankfull
discharge.
bankfull discharge. 1. For a natural channel that is not adapting to hydrologic change in its
watershed, it is the discharge that occurs when the water just fills the channel to the top of its
banks and begins to overflow onto a floodplain. 2. The discharge at which channel maintenance
is most effective, that is, the discharge at which moving sediment, forming or removing bars,
forming or changing bends and meanders, and generally doing work that results in the average
morphologic characteristics of channels.
baseflow. Sustained flow of a stream in the absence of direct runoff. It includes natural and
human-induced streamflows. Natural base flow is sustained largely by groundwater discharges.
bathymetry. The measurement of depths of water in oceans, seas, and lakes; also information
derived from such measurements.
bed-load. In-stream sediment transport mode in which individual particles either roll or slide
along the stream bed as a shallow, mobile layer a few particle diameters deep (the particle size
depends on the energy level of the flowing water).
benthic/benthos. An organism that feeds on the sediment at the bottom of a waterbody such
as an ocean, lake, or river.
berm. A low earth fill constructed in the path of flowing water to divert its direction, or
constructed to act as a counterweight beside the road fill to reduce the risk of foundation failure.
Glossary
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
bioinfiltration. A stormwater management practice where runoff is routed through a soil media
that is vegetated. This practice functions in a manner analogous to bioretention systems but has
a higher infiltration capacity, and thus would be categorized as an infiltration process.
biological treatment. A treatment technology that uses bacteria to consume organic waste.
bioretention. A stormwater management practice that is designed to provide both temporary
surficial water storage and runoff retention subsurface in soil media. Runoff is directed to
shallow depressions where it is infiltrated, filtered or evapotranspirated. These systems are
typically designed with a soil media selected to promote infiltration and runoff retention and are
vegetated with plants picked to withstand both inundation and drought. Bioretention systems
also be used to filter runoff to trap and in some cases degrade pollutants such as oils and
greases. This practice is often categorized under filtration although it has additional functions.
Some systems are build with underdrain or overdrain systems to convey excess runoff off-site.
bioswale. A relatively wide, shallow, open channel, typically vegetated with turf grasses, with a
slight gradient. These systems are designed to let water flow slowly through the turf grasses.
The roughness of the turf slows the runoff velocity and provides some filtration and settling of
suspended solids. Runoff volumes can also be reduced through infiltration depending on the
porosity of the underlying soils. Swales can be designed with underdrains to convey excess
runoff from saturated soils.
blue roofs. A practice that is designed to provide temporary storage of stormwater and slowly
release stormwater runoff using the roof surface of a structure. Also referred to as rooftop
detention.
branch packing. A form of soil bioengineering that uses alternating tiers of live branch cuttings
and compacted backfill to repair small localized slumps and holes in slopes and a means of
reducing the erosive potential of incoming flows at their source.
breakwater. A wave energy barrier designed to protect the land or nearshore area behind them
from the direct assault of waves.
brownfield. An abandoned, idled, or underused industrial and commercial facility/site where
expansion or redevelopment is complicated by real or perceived environmental contamination.
They can be in urban, suburban, or rural areas. EPA's Brownfields initiative helps communities
mitigate potential health risks and restore the economic viability of such areas or properties.
brush layering. A form of soil bioengineering that uses live branch cuttings laid flat into small
benches excavated in the slope face perpendicular to the slope contour.
Glossary
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
buffer strip. 1. Area between a stream and construction activities that achieves sediment
control by using the natural filtering capabilities of the forest floor and litter. 2. Strips of grass or
other erosion-resisting vegetation between or below cultivated strips or fields.
bulkhead. A structure or partition to retain or prevent sliding of the land. A secondary purpose is
to protect the upland against damage from wave action.
catch basin. A catch basin is a device that receives stormwater drainage from an outside
surface area. They are usually in parking lots or in areas where the removal of stormwater
buildup is desirable.
channel incision and widening. A process of channel degradation that results in a lower
elevation channel surrounded by one or more elevated terrace(s) that once were floodplains.
The interplay of channel incising (deepening) and widening is caused by changes in streamflow
or sediment delivery.
channel reconfiguration. River and stream channel engineering for the purpose of flood
control, navigation, drainage improvement, and reduction of channel migration potential;
activities include the straightening, widening, deepening, or relocation of existing stream
channels, clearing or snagging operations, the excavation of borrow pits, underwater mining,
and other practices that change the depth, width, or location of waterways or embayments in
coastal areas.
channelization. River and stream channel engineering undertaken for the purpose of flood
control, navigation, drainage improvement, and reduction of channel migration potential.
Activities such as straightening, widening, deepening, or relocating existing stream channels
and clearing or snagging operations fall into this category.
chisel plowing. Preparing croplands by using a special implement that avoids complete
inversion of the soil as in conventional plowing. Chisel plowing can leave a protective cover or
crops residues on the soil surface to help prevent erosion and improve filtration.
cistern. A tank or storage facility used to store water for a home or farm; often used to store
rain water.
clasts. Individual sedimentary particles such as a grain of sand, pebble, or boulder that make
up a sedimentary rock or deposit.
clear cut. A silvicultural system in which all merchantable trees are harvested within a specified
area in one operation to create an even-aged stand.
Glossary 5
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
cluster treatment system. A wastewater treatment system designed to serve two or more
sewage-generating dwellings or facilities with multiple owners that is not part of a centralized
collection system that discharges to any point sources and that treats and disperses effluent to
soil-based dispersal systems similar to onsite systems.
coarse woody debris (CWD). A large tree part, conventionally a piece greater than 10 cm in
diameter and 1 m in length.
coconut fiber roll. Cylindrical structures composed of coconut husk fibers bound together with
twine woven from coconut material to protect slopes from erosion while trapping sediment,
which encourages plant growth within the fiber roll.
colloids. Very small, finely divided solids (that do not dissolve) that remain dispersed in a liquid
for a long time because of their small size and electrical charge.
combined sewer overflow (CSO). A discharge of a mixture of stormwater and domestic waste
when the flow capacity of a sewer system is exceeded during rainstorms.
compost amendment. Organic matter that is added to soil to improve infiltration.
composting. The controlled biological decomposition of organic material in the presence of air
to form a humus-like material. Controlled methods of composting include mechanical mixing and
aerating, ventilating the materials by dropping them through a vertical series of aerated
chambers, or placing the compost in piles out in the open air and mixing it or turning it
periodically.
concentrated flow. Rills, ephemeral gullies, gullies, channels, streams and rivers are examples
on the landscape of areas where concentrated flow erosion occurs. Concentrated flow erosion
is also a culprit in embankment breaching and auxiliary spillway failure on earthen dams.
construction runoff intercepts. A temporary berm or channel constructed across a slope to
collect and divert runoff.
controlled-release or slow-release fertilizers. Inorganic or organic fertilizers that are
characterized by a slow rate of release, long residual, low burn potential, and low water
solubility. Several categories of slow-release nitrogen fertilizers are commercially available,
including urea-formaldehyde, isobutylidene diurea, sulfur coated urea, plastic coated fertilizers,
and natural organics.
Glossary
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
conventional tilling. Tillage operations considered standard for a specific location and crop
and that tend to bury the crop residues.
core aeration. Increasing air penetration of the soil by removing plugs of soil. A heavy machine
with hollow prongs is moved across a lawn pushing the prongs into the soil and pulling out plugs
of soil.
cover crop. A crop that provides temporary protection for delicate seedlings or provides a cover
canopy for seasonal soil protection and improvement between normal crop production periods.
crown fire. The movement of fire through the crowns of trees or shrubs more or less
independently of the surface fire.
cross-sectional area. The cross-sectional area of a stream or tributary stream channel is
determined by multiplying the stream or tributary stream channel width by the average stream or
tributary stream channel depth.
cosspipe or sluice pipe (also called culvert). A conduit used to enclose a flowing body of water
to allow it to pass underneath a road, railway, or embankment.
culvert. A metal, wooden, plastic, or concrete conduit through which surface water can flow
under or across roads.
curb extension. A section of sidewalk designed to contain soils and vegetation to filter runoff,
reduce runoff velocities and in some cases infiltrate runoff. Curb cuts or gaps in the curbs are
used to route runoff from street surfaces into this cells.
cut-and-fill. An earth-moving process that entails excavating part of an area and using the
excavated material for adjacent embankments or fill areas.
demand-dosing. A configuration in which a specific volume of effluent is delivered to a
component (e.g., a drainfield) according to patterns of wastewater generation from the source.
denitrification. The biological reduction of nitrate to nitrogen gas by bacteria in soil.
denitrification enzyme assay. An assay used to quantify the initial rate, or Phase I, of
denitrification using the acetylene block technique to prevent the reduction of N2O to N2.
Glossary
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
design flow. Projected flow through a watercourse that will recur with a stated frequency. The
projected flow for a given frequency is calculated using statistical analysis of peak flow data or
using hydrologic analysis techniques. (See storm return period).
dewater. Removing or draining the water from a site, stream, or trench.
digestion. The biochemical decomposition of organic matter, resulting in partial gasification,
liquefaction, and mineralization of pollutants.
dispersal. Spreading of effluent through the final receiving environment, typically soil.
distribution box. A level, watertight structure that receives septic tank effluent and distributes it
via gravity in approximately equal portions to two or more trenches or two or more laterals in a
bed.
dormant post plantings. Plantings of dormant cottonwood, willow, poplar, or other species
embedded vertically into streambanks to increase channel roughness, reduce flow velocities
near the slope face, and trap sediment as they grow.
dosing and resting. A configuration in which a specific volume of effluent is delivered to a
component according to a prescribed interval, regardless of facility water use.
drainage. Improving the productivity of agricultural land by removing excess water from the soil
by such means as ditches or subsurface drainage tile lines.
drainage density. In hydrologic terms, the relative density of natural drainage channels in a
given area. It is usually expressed in terms of miles of natural drainage or stream channel per
square mile of area and obtained by dividing the total length of stream channels in the area in
miles by the area in square miles.
drainage intensity (Dl). The drainage rate that occurs when the water table is at the soil
surface; it increases with drain depth and decreases with drain spacing.
drainage water management. A practice in which the outlet from a conventional drainage
system is intercepted by a water control structure that effectively functions as an in-line dam,
allowing the drainage outlet to be artificially set at levels ranging from the soil surface to the
bottom of the drains.
Glossary
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
drainfield (soil treatment area). Physical location where final treatment and dispersal of
effluent occurs; includes drainfields, drip fields and spray fields.
duff. The accumulation of needles, leaves, and decaying matter on the forest floor.
effluent. Partially or fully processed liquid flowing out of a sewage treatment component or
device.
energy signature. The characteristics of a stream system to allow it to transport the flows of
water and sediment provided by its watershed in an efficient and stable manner.
entrapped mixed microbial cells (EMMC) process. A process in which dilute wastewater is
passed through a cellulose triacetate matrix containing microbial cells for the purpose of
removing carbon and nitrogen.
ephemeral drainage. A channel that carries water only during and immediately following
rainstorms. Sometimes referred to as a dry wash.
epilimnion. The upper waters of a thermally stratified lake subject to wind action.
erosion control blankets. A manufactured sheet, typically rolled on a spool consisting of a
matrix of straw, coconut fiber, aspen fiber, jute, or polypropylene (plastic) that is woven,
stitched, glued, or bound together, which is placed on disturbed areas to provide temporary
erosion control and encourage establishment of vegetation.
essential turf. Turf required for the identified needs of the facility or jurisdiction, e.g., security,
historic preservation, access, other designated uses such as recreation, mental health
restoration or rehabilitation.
eutrophication. The slow aging process during which a lake, estuary, or bay evolves into a bog
or marsh and eventually disappears. During the later stages of eutrophication the waterbody is
choked by abundant plant life because of higher levels of nutritive compounds such as nitrogen
and phosphorus. Human activities can accelerate the process.
evapotranspiration. The loss of water from the soil both by evaporation and by transpiration
from the plants growing in the soil.
fast-release fertilizer. A synthetic fertilizer that releases its nutrients (especially N) rapidly (e.g.,
urea, ammonium nitrate).
Glossary
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
feed pump. Mechanical device for driving fluid flow or for raising or lifting a fluid by either
suction or pressure or both.
filter strips. Area of vegetation used for removing sediment, organic matter, and other
pollutants from runoff or wastewater.
filtration. A treatment process, under the control of qualified operators, for removing solid
(particulate) matter from water by means of porous media such as sand or a man-made filter;
often used to remove particles that contain pathogens.
first flush. The condition, often occurring in storm-sewer discharges and CSOs, in which a
disproportionately high pollutant load is carried in the first portion of the discharge or overflow.
fish ladder or lift. A series of ascending pools, similar to a staircase, that enables fish to
migrate up the river past dams. Also called a fishway.
fish runs. The place where fish, such as native steelhead trout and salmon, return from the
ocean each spring to spawn in the rivers or streams where they were born. Can also refer to the
group of fish that is migrating up the stream.
fish tagging. The placement of identifying tags or markers, typically permanent, on individual
captured fish specimens for the purposes of later retrieval and analysis for species migration,
growth, and overall health.
floe. A clump of solids formed in sewage by biological or chemical action.
floodplain. The flat or nearly flat land along a river or stream or in a tidal area that is covered by
water during a flood.
flow regime. Combinations of river discharge and corresponding water levels and their
respective (yearly or seasonally) averaged values and characteristic fluctuations around these
values.
flow velocities. The speed, expressed in units of length per unit of time, at which a fluid flows
through a culvert, channel or other conveyance.
flue gas desulfurization. A technology that employs a sorbent, usually lime or limestone, to
remove sulfur dioxide from the gases produced by burning fossil fuels. Flue gas desulfurization
is current state-of-the art technology for major SO2 emitters, like power plants.
10 Glossary
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
flume. A natural or man-made channel that diverts water.
fluvial. Of or relating to flowing waters, especially rivers.
fluvial aggradation. General and progressive raising of a stream bed by deposition of sediment
carried by the stream.
footer. Stone, concrete or other rigid structural material placed underneath other materials to
provide a foundation or bearing surface.
gabion. A rectangular basket or mattress made of galvanized, and sometimes PVC-coated,
steel wire in a hexagonal mesh. Gabions are generally subdivided into equal-sized cells that are
wired together and filled with 4- to 8-inch-diameter stone, forming a large, heavy mass that can
be used as a shore-protection device.
geomorphology. That branch of both physiography and geology that deals with the form of the
Earth, the general configuration of its surface, and the changes that take place in the evolution
of landform.
geotextile filtration. The use of geotextiles (permeable fabrics) to separate solids and liquids in
such materials as lagoon sludge and liquid manure.
grade breaks. An intentional increase in road elevation on a downhill grade that causes water
to flow off of the road surface.
grade stabilization structure. A structure used to control the grade and head cutting in natural
or artificial channels.
grassed swales. A term used to describe a vegetated open runoff channel planted with grasses
or turf. Similar terms include: grassed channel, dry swale, wet swale, biofilter, or bioswale.
These systems are designed to treat and attenuate stormwater runoff. As runoff flows along
these channels, the vegetation in the channel promotes filtration, settling and infiltration of runoff
into the underlying soils. The specific design features and methods of treatment differ in each of
these designs, but are improvements on the traditional drainage ditch. These designs
incorporate modified geometry and other features for use of the swale as a treatment and
conveyance practice.
Glossary 11
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
graywater. Any washwater that has been used in a home or business, except water from
toilets. This water is considered to be more re-useable, especially for landscape irrigation
purposes.
grazing. Feeding on standing vegetation, as by livestock or wild animals.
greenfields. Previously undeveloped land such as forests, meadows or other "natural lands."
green infrastructure. A term that has two commonly used meanings. The more common usage
refers to vegetated landscapes that are conserved or restored for ecological or anthropological
reasons, e.g., wildlife habitat, flood protection, drinking water source protection and air quality
and urban heat island concerns.
This term is also used to connote practices and strategies used to reduce the impact of wet
weather events (rainfall and snow melt) on receiving waters. In this usage, green infrastructure
is often also called low impact development or LID and is used to describe an array of
strategies, products, technologies, and practices that are designed to mimic the behavior of
natural systems as they relate to runoff, watershed and site hydrology and pollutant reduction.
These systems are typically designed using an integrated design approach that relies on
engineering, hydrological, biological, architectural, and planning concepts and practices to plan,
design and manage runoff through plant and soil uptake, filtration, infiltration,
evapotransipiration and the harvest and use of runoff.
green roof. Also known as eco-roofs or rooftop gardens, green roofs are engineered soil media
systems that are planted on rooftops and designed to reduce runoff, combined sewer overflows,
urban heat island impacts and provide other ecological and human benefits such as aesthetics,
wildlife habitat and aesthetics. The soil media mix and vegetation are planted over existing roof
structures, and consist of a waterproof, root-safe membrane that is covered by a drainage
system, lightweight growing medium, and plants. Green roofs reduce rooftop and building
temperatures, filter pollution, lessen pressure on sewer systems, and reduce the heat island
effect.
grid point data. Data that is collected at the intersections of imaginary or real lines laid over a
surface in a grid pattern.
grinder pump system. A pump that shreds solids in a waste stream and conveys the resulting
mixture under pressure to a subsequent system component.
groin. A shore protection structure built (usually perpendicular to the shoreline) to trap littoral
drift or retard erosion of the shore.
12 Glossary
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
ground fuels. All combustible materials below the surface litter, including duff, roots, peat and
saw dust dumps that normally support a glowing combustion without flame.
gully. A channel or miniature valley cut by concentrated, non-continuous runoff such as during
snowmelt or following heavy rains.
gully erosion. Severe erosion in which trenches are cut to a depth greater than 30 centimeters
(a foot). Generally, ditches deep enough to cross with farm equipment are considered gullies.
highly erodible lands (HELs). Land that is very susceptible to erosion, including fields that
have at least 1/3 or 50 acres of soils with a natural erosion potential of at least 8 times their T
value. More than 140 million acres are classified as HEL. Farms cropping highly erodible land
and under production flexibility contracts must be in compliance with a conservation plan that
protects this cropland.
hi-input turf. Turf that requires irrigation, frequent mowing, fertilization and/or pesticide
treatment.
hillslope. A part of a hill between its crest and the drainage line at the foot of the hill.
hydraulic connectivity. The ability of the soil to transmit water. Also commonly known as the
permeability. Darcy found that to relate the flow rate to the hydraulic head and area of flow
required a constant of proportionality (termed k) as the hydraulic connectivity. It has units of
velocity. Note that the value is a function of both the porous media and the fluid.
hydraulic residence time. The average time an element spends in a given environment
between the time it arrived and the time it is removed by some process. In the ocean, residence
time is defined as the concentration in sea water relative to the amount delivered to the ocean
per year; in groundwater, it is the time elapsed between water being recharged to the aquifer; in
lakes and reservoirs, it is the time elapsed between a parcel of water entering the waterbody
and leaving it.
hydraulic resistance. In hydraulics, resistance is the condition engendered by an obstruction
or restriction in the flow path. Hydraulic resistance in a forest setting is the obstruction of the
flow of water. Woody debris, forest litter, and surface irregularities and structures that slow the
flow of water increase hydraulic resistance.
hydric soil. A soil that is saturated, flooded, or ponded long enough during the growing season
to develop anaerobic (oxygen-lacking) conditions that favor the growth and regeneration of
hydrophytic vegetation.
Glossary 13
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
hydrodynamic simulations. Computer simulations of the motion or movement of water in a
stream, lake or estuary.
hydrologic cycle. Movement or exchange of water between the atmosphere and earth.
hydrologic extremes. Hydrologic events that change stream flow conditions, such as droughts
and floods, of significant magnitude compared to normal baseline conditions.
hydrology. The science dealing with the properties, distribution, and circulation of water.
hydromodification. Alteration of the hydrologic characteristics of landscapes, drainage ways
and waters of the US that result in changes in water balance, stream morphology, habitat,
groundwater recharge, evapotranspiration rates and surface runoff.
immobilization and mineralization. In mineralization, the nitrogen (N) in plant tissue is
converted by soil microbes into a form (nitrate) that subsequent plants can use. Immobilization
is the process by which plant usable forms of N in the soil become unavailable for subsequent
crop growth. Because microbial populations increase with the growth of a cover crop, N
contained in the cover crop and the soil can be immobilized or tied up as part of the physical
structure of the microbes. As a result, the cover crop N might not be available for uptake by the
following crop. When the microbes die, the N is mineralized and becomes available for
subsequent crop use.
impervious surfaces. A hard surface area that either prevents or retards the entry of water into
the soil mantle or causes water to run off the surface in greater quantities or at an increased
rate of flow. Common impervious surfaces include rooftops, walkways, patios, driveways,
parking lots, storage areas, concrete or asphalt paving, and gravel roads.
impoundment. A body of water or sludge confined by a dam, dike, floodgate, or other barrier.
incised. A channel that has been cut relatively deep into underlying formation by natural or
human-induced processes.
indoor ozone systems. A controversial indoor technique that uses ozone for broiler house
cleaning and in-house air contaminant (ammonia) control.
infiltration. The movement of water from the land surface into the soil.
14 Glossary
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
infiltration basin or trench. A drainage facility designed to use the hydrologic process of runoff
soaking into the ground, commonly referred to as percolation, to dispose of stormwater. Note:
Infiltration trenches are typically not vegetated or designed to significantly filter pollutants from
runoff.
inorganic nitrogen. The element nitrogen in combination with other mineral elements and not
derived from plant or animal sources.
integrated pest management. The use of pest and environmental information in conjunction
with available pest control technologies to prevent unacceptable levels of pest damage by the
most economical means and with the least possible hazard to persons, property, and the
environment.
intercropping. The growing of two or more species of crops simultaneously, as in alternate
rows in the same field or single tract of land.
interstitial. The matrix of air or liquid between sediment particles.
inverts. The bottom of a drainage facility along which the lowest flows pass.
labile carbon. The highly reactive fraction of soil organic carbon with the most rapid turnover
times; its oxidation drives the flux of CO2 between soils and atmosphere. Labile organic carbon
decomposes rapidly in the water column or in sediments, on a time scale of days to weeks;
refractory organic carbon requires more time.
land applied. The reuse of reclaimed water or the use or disposal of effluents or wastewater
residuals on, above, or into the surface of the ground through spray fields, land spreading, or
other methods.
landing. A place in or near the forest where logs are gathered for further processing or
transport.
large wood structures (LWS). See large woody debris.
large woody debris. Also called large wood structures. A large tree part, conventionally a piece
greater than 10 cm in diameter and 1 m in length.
leaching. The process by which soluble constituents are dissolved and filtered through the soil
by a percolating fluid.
Glossary 15
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
leaf litter. Also called duff. Leaves and twigs fallen from forest trees.
livestock exclusion fencing. Fencing that keeps livestock away from rivers and streams.
load. The quantity of sediment transported by a current. It includes the suspended load of small
particles and the bedload of large particles that move along the bottom.
longitudinal rutting. Ruts formed along the length of the road from tire pressure.
longitudinal zones. The longitudinal zones of a river corridor include the headwaters (zone 1),
the transfer zone (zone 2), and the depositional zone (zone 3).
lotic system. Flowing waters, as in streams and rivers.
low-input turf. Turf that requires little or no maintenance, i.e., fertilization, irrigation, pesticide
applications.
low-mow turf. Turf that is only infrequently mowed. Turf under this category would be mowed
as little as possible, and mowing frequency would be based on issues such as security, pests,
fire hazard, or suppression of woody species.
macroaggregate. A relatively large particle (as of soil).
macropores. Secondary soil features such as root holes or desiccation cracks that can create
significant conduits for movement of non-aqueous phase liquid and dissolved contaminants, or
vapor-phase contaminants.
matrix based fertilizers (MBFs). Fertilizers formulated to reduce nitrate, ammonium, and total
phosphorus leaching through binding of nitrogen (N) and phosphorus (P), and in some cases
via mixtures with aluminum sulfate, iron sulfate, starch, chitosan, or lignin. When N and P are
released, the chemicals containing these nutrients in the MBF temporarily bind N and P to an
aluminum sulfate or iron sulfate starch- chitosan- lignin matrix.
mat/tree collar. A sunlight-blocking device used to block the growth of grass or weeds
immediately adjacent to a newly planted tree. It is commonly made of 2.5-mil, UV-stabilized,
carbon-black plastic; about 3 feet x 3 feet (1 sq. yard) slit to easily fit around the tree.
16 Glossary
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
mechanical site preparation. The practice of cutting all standing material with blades or
choppers to prepare an area for establishing a future forest either by artificial or natural means.
Other practices include disking, bedding, and raking.
mesohabitat. Distinct units of habitat within an ecosystem.
microfauna. Soil-dwelling micro-organisms (animals) that cannot be seen with the naked eye.
microfiltration. Using a device with a filter media to physically prevent biological contamination
from passing through. Ceramic and solid block carbon are commonly used to provide
microfiltration.
miter drain. A drain that is at an angle (e.g., 45 degrees) to the surface that is being drained
(e.g., a grassed swale), as opposed to a drain laid flat on the surface that is being drained.
morphology. The branch of geology that studies the characteristics and configuration and
evolution of rocks and land forms.
mouldboard ploughing. Conventional tillage using a moldboard plow. It turns over the soil and
typically leaves less than 15 percent residue cover after planting.
native landscaping. Landscaping that is designed to use native plants adapted to the specific
geographic location of their origin.
nitrate flux. The flow of nitrate (the most soluble and mobile form of nitrogen) out of a system,
as from groundwater to streams, streams to rivers, and rivers to bays or oceans.
nitrification. The process whereby ammonia in wastewater is oxidized to nitrite and then to
nitrate by bacterial or chemical reactions.
no-mow turf. Grasses that do not need mowing and are allowed to reach their mature state,
e.g., switch grasses and other native grasses.
no till. Planting crops without prior seedbed preparation, into an existing cover crop, sod, or
crop residues, and eliminating subsequent tillage operations.
no-till disk aeration. Aeration that uses methods similar to no-till or conservation tillage
seeding of crops, which disrupts the soil surface in a series of parallel rows. The soil is aerated
Glossary 17
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
using an aeration device fashioned by attaching cores, tines, or metal flashing (disk aeration) to
rows on a metal plate and pushing the implement into the soil.
nonessential turf. Turf not necessary to achieve the intended goals of the facility or jurisdiction.
nonpoint source. Diffuse runoff (i.e., without a single point of origin or not introduced into a
receiving stream from a specific outlet). This document uses the term nonpoint source broadly,
as EPA has in the past, to refer to sources that currently are treated as nonpoint sources in
EPA's implementation of section 319 of the Clean Water Act. Some of these sources may
legally be made subject to regulation as point sources under section 402(p) of the Clean Water
Act. EPA has designated several categories of these stormwater sources for regulation, such as
small municipal separate storm sewer systems, and may designate others for regulation in the
future.
nutrient. Any substance assimilated by living things that promotes growth. The term is generally
applied to nitrogen and phosphorus in wastewater but is also applied to other essential and
trace elements.
nutrient use efficiency (NUE). A measure of how much crop is produced per unit of nutrient
supplied. A greater NUE leaves less nitrogen and phosphorus available for transport to
waterbodies.
on-site system. A wastewater treatment system relying on natural processes or mechanical
components or both to collect and treat sewage from one or more dwellings, buildings, or
structures and disperse the resulting effluent on property owned by the individual or entity.
organic turf management. Turf managed without the use of inorganic fertilizers or pesticides.
organic matter. The organic component of the soil consisting in living organisms, dry plants
and residues of animal origin. In a mass unit, this organic component is the most chemically
active of the soil. Such a component stores several essential elements, stimulates the proper
structure of the soil, is a source with capacity for the exchange of cations and regulates the pH
changes, supports the relationship between air and water in the soil, and is a huge geochemical
storage of carbon.
oxidation-reduction potential. The electric potential required to transfer electrons from one
compound or element (the oxidant) to another compound (the reductant); used as a qualitative
measure of the state of oxidation in water treatment systems.
18 Glossary
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
P-saturation. The amount of phosphorus in soil divided by the amount of phosphorus that can
be fixed by the soil.
participate bound. The condition in which a pollutant constituent attaches physically, strongly
or weakly, to sediments within a stream system.
pasture. Land used primarily for the production of domesticated forage plants for livestock (in
contrast to rangeland, where vegetation is naturally occurring and is dominated by grasses and
perhaps shrubs). Rotation pasture or cropland under winter cover crops is not included in this
definition. The 1992 national resources inventory recorded 126 million acres of pastureland, 9
percent of all nonfederal rural lands.
peak flow. The maximum flow through a watercourse that will recur with a stated frequency.
The maximum flow for a given frequency can be based on measured data, calculated using
statistical analysis of peak flow data, or calculated using hydrologic analysis techniques.
permeable reactive barriers. A subsurface emplacement of reactive materials designed as a
preferential conduit for treating contaminated groundwater flow.
phase construction. Disturbance of small portions of a site at a time to prevent erosion from
the dormant parts.
phreatic surface. The free surface of groundwater at atmospheric pressure.
phytoremediation. A practice used to reduce soil contaminant loadings through the use of
plants selected to uptake or breakdown the contaminants. In cases where plants cannot
metabolize and breakdown the contaminants, vegetative matter might need to be removed for
further processing or disposal.
phytotechnology. A term referring to technologies that use living plants.
planter box. A small, contained vegetated area that is used to collect and treat stormwater
through the mechanisms provided by bioretention designs. There are three general types of
planter boxes: (1) contained planter that is used for planting trees, shrubs, and ground cover
that is placed over an impervious surface; (2) infiltration planter that is a structural landscaped
reservoir used to collect, filter, and infiltrate stormwater run-on; and (3) flo-through planter that is
similar to an infiltration planter except it has a waterproof lining allowing it to be used next to
foundation walls. Other terms used for this practice include stormwater planter, vegetated
planter, tree box.
Glossary 19
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
plume. A definable, three-dimensional region of effluent created by the movement of
groundwater beneath its source.
plunge pool. A natural or sometimes artificially created pool that dissipates energy of free
falling water. The basin is at a safe distance downstream of the structure from which the water
is being released.
pore water pressure. The pressure exerted on its surroundings by water held in pore spaces in
rock or soil.
porosity. The degree to which soil, gravel, sediment, or rock is permeated with pores or cavities
through which water or air can move.
pre-development hydrology. The runoff characteristics in a watershed before urban
development in respect to the volume, rate, duration, and temperature of runoff.
production area of an AFO. That part of an animal feeding operation that includes the animal
confinement area, the manure storage area, the raw materials storage area, and the waste
containment areas. The animal confinement area includes open lots, housed lots, feedlots,
confinement houses, stall barns, free stall barns, milkrooms, milking centers, cowyards,
barnyards, medication pens, walkers, animal walkways, and stables. The manure storage area
includes lagoons, runoff ponds, storage sheds, stockpiles, under house or pit storages, liquid
impoundments, static piles, and composting piles. The raw materials storage area includes feed
silos, silage bunkers, and bedding materials. The waste containment area includes settling
basins, and areas within berms and diversions that separate uncontaminated stormwater. Also
included in the definition of production area is any egg washing or egg processing facility, and
any area used in the storage, handling, treatment, or disposal of mortalities.
push outs. A type of road drainage structure that drains topographic lows or saddles on a road
by directing runoff away from the road from both road directions.
rain garden. A depressed area of the ground planted with vegetation, allowing runoff from
impervious surfaces such as parking lots and roofs the opportunity to be collected and infiltrated
into the groundwater supply or returned to the atmosphere through evaporation and
evapotranspiration. Rain gardens are typically cheaper to build and design than bioretention or
bioinfiltration cells because they are often built without specific performance standards and
without the assistance of a certified professional to design them.
recirculating media filter. A wastewater treatment system component featuring a layer of
sand, gravel, or other material, on which effluent is applied and treated via microbial growth on
20 Glossary
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
the surface of the media, allowing the effluent to trickle through. A portion of the effluent is
returned to another system component for further treatment or to facilitate a treatment process.
reforestation. The establishment of a forest through artificial plantings or natural regeneration.
reinforcement planting. Additional trees and shrubs that are planted during the short-term
maintenance phase (approximately 2 years after initial plantings) of a riparian forest buffer
restoration to replace any plants that did not survive and to enhance the buffer.
retrofits. Installation of a new or redesigned stormwater facility to treat stormwater from existing
impervious area, including roofs, patios, walkways, and driving or parking surfaces.
return walls. Walls constructed at the ends of seawalls, bulkheads, or revetments
perpendicular to the shoreline to prevent flanking of the primary shore protection structure.
revetment. A facing of stone, concrete, and the like, built to protect a scarp, embankment, or
shore structure against erosion by wave action or currents.
ridge tillage. A type of soil conserving tillage in which the soil is formed into ridges and the
seeds are planted on the tops of the ridges. The soil and the crop residue between the rows
remain largely undisturbed. The practice offers opportunities to reduce crop production costs by
banding fertilizers and pesticides and reducing the need for field trips.
riffle. A shallow part of the stream where water flows swiftly over completely or partially
submerged obstructions to produce surface agitation.
rill. A small channel eroded into the soil by surface runoff; it can be easily smoothed out or
obliterated by normal tillage.
riparian area. Vegetated ecosystems along a waterbody through which energy, materials, and
water pass. Riparian areas characteristically have a high water table and are subject to periodic
flooding and influence from the adjacent waterbody. These systems encompass wetlands,
uplands, or some combination of the two, although they will not in all cases have all the
characteristics necessary for them to be classified as wetlands.
riparian buffer. A specific area to be managed within a riparian area.
riparian habitat. Areas adjacent to rivers and streams with a differing density, diversity, and
productivity of plant and animal species relative to nearby uplands.
Glossary 21
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
road failure. A portion or location along a forest road where generally erosion or poor
construction has resulted in the surface of the road falling away and leaving the road
impassable or compromising the intended drainage of the road surface.
road prism. All parts of a road including cut banks, ditches, road surfaces, road shoulders, and
road fills.
road profile. The cross-sectional shape of the road surface in relation to the road corridor
traversing the surrounding landscape.
root wad revetments. Logs with attached root masses that are placed in and on streambanks
to provide streambank erosion, trap sediment, and improve habitat diversity.
row crop agriculture. The rows or planting beds are far enough apart to permit the operation of
machinery between them for cultural operations.
scour. Soil erosion when it occurs underwater, as in the case of a streambed.
scour pool. Removal of underwater material by waves and currents, especially at the base or
toe of a shore structure.
seawalls. A structure separating land and water areas, primarily designed to prevent erosion
and other damage due to wave action.
sediment. Topsoil, sand, and minerals washed from the land into water, usually after rain or
snow melt.
sediment basin/rock dams. Barriers, often employed in conjunction with excavated pools,
constructed across a drainage way or off-stream and connected to the stream by a flow
diversion channel to trap and store waterborne sediment and debris.
sediment fence (also called silt fences). A temporary sediment control device used on
construction sites to protect water quality in nearby surface waters from sediment (loose soil) in
stormwater runoff. A typical fence consists of a piece of synthetic filter fabric (also called a
geotextile) stretched between a series of wooden or metal stakes.
sediment transport capacity and competence. The ability or efficiency of a stream system to
move sediment.
22 Glossary
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
sediment trap. A structure or vegetative barrier designed to collect soil material transported in
runoff and also to reduce water flow velocity and therefore scouring and erosion. Sediment traps
mitigate siltation of natural drainage features.
seeding. The establishment of vegetated cover on a disturbed site by applying plant seeds
and as appropriate, fertilizer, lime, or other amendments.
septage. Liquid and residuals removed from a septic tank or other sewage pretreatment device
or holding facility, such as a seepage pit, cesspool, or portable toilet.
septic tank effluent gravity (STEG) collection system. A collection system that uses septic
tanks to separate solids and allow gravity flow of effluent to a subsequent component.
septic tank effluent pump (STEP) collection system. A collection system that uses a septic
tank to separate solids and incorporates a pump and associated parts to convey effluent under
pressure to a subsequent component.
sequencing batch reactor. A series of components designed to treat wastewater in batches,
one process at a time. Typically, it involves activated sludge and other processes carried out in
the same tank in stepwise order (e.g., fill, treat, settle, decant, and draw).
setback. A distance between a water resource and an activity (e.g., manure spreading) within
which the activity cannot be carried out. The purpose of a setback is to reduce the potential for
contaminants to reach ground or surface water. Properly managed setbacks improve water
quality by acting as filters for water passing over or through the soil toward a water resource.
shear strength. The internal resistance of a body to shear stress, which typically includes
frictional and cohesive components and expresses the ability of soil to resist sliding.
sheetflow. Term used to describe the movement of water laterally across the surface of the
ground, rather than flowing in defined channels or depressions.
silt fence (See sediment fence.)
silviculture. The management of forest land for timber production.
silvopasture. An agroforestry application establishing a combination of trees or shrubs and
compatible forages on the same acreage.
Glossary 23
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
single-pass. A wastewater flow configuration wherein effluent moves through a treatment
component only once.
site fingerprinting. 1. Site clearing and development using minimal disturbance of existing
vegetation and soils. 2. Restricting ground disturbance to areas where structures, roads, and
rights of way will exist after construction is completed.
skid trail. A temporary, nonstructural pathway over forest soil used to drag felled trees or logs
to the landing.
slag filter. A filter filled with electric arc furnace steel slag, a by-product of making steel, to treat
barnyard runoff and milkhouse waste.
slash. The unwanted, unused, and generally unmerchantable accumulation of woody material,
such as large limbs, tops, cull logs, and stumps, that remains as forest residue after timber
harvesting.
slit aeration. A soil aerator, the most common for agronomic use, in which tines are pushed
into the soil to make elongated holes.
slough. A marshy or reedy pool that contains areas of slightly deeper water and a slow current.
sludge. Accumulated solids and associated entrained water within a wastewater pretreatment
component, generated during the biological, physical, or chemical treatment; coagulation; or
clarification of wastewater.
sluicing. The practice of releasing water through the sluice gate of an impoundment rather than
through the turbines.
sodding. A permanent erosion control practice involving laying a continuous cover of grass sod
on exposed soils.
soil dispersal field (soil treatment area). A physical location where final treatment and
dispersal of effluent occurs; includes drainfields, drip fields and spray fields.
spur road. A short road that branches from a major forest road and that is generally used to
access specific areas for harvesting.
24 Glossary
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
stormflow. The portion of streamflow attributable to precipitation that enters the channel
(generally as overland flow or shallow subsurface flow) within a short time frame in association
with storms (as opposed to baseflow, which enters the channel slowly from groundwater
sources).
storm return period. The recurrence interval or an estimate of the interval of time between
storms of a certain intensity or size. See also Design Flow.
stream corridor. The area that consists of the stream channel itself, the floodplain, and a
transitional zone between the floodplain and the surrounding landscape.
stream geometry. The physical form assumed by a stream system that includes channel depth,
width, longitudinal slope, and planform.
stream morphology. The science of analyzing the structural makeup of rivers and streams and
how they change over time.
streamside management area. A designated area that consists of the stream itself and an
adjacent area of varying width where management practices that might affect water quality, fish,
or other aquatic resources are modified. The SMA is not necessarily an area of exclusion but an
area of closely managed activity. It is an area that acts as an effective filter and absorptive zone
for sediments; maintains shade; protects aquatic and terrestrial riparian habitats; protects
channels and streambanks; and promotes floodplain stability.
street sweeping. The use of self-propelled and walk-behind sweeping and vacuum equipment
to remove sediment and other debris from streets, roadways, parking lots and sidewalks.
struvite formation. The common name for magnesium ammonium phosphate hexahydrate
(MgNH4PO4 • 6(H2O)). Struvite can naturally form and clog pumps and pipes when recycling
lagoon liquid, and struvite accumulation is a common problem in pumping systems for
anaerobic treatment portions of municipal waste treatment systems. Although components
designed to promote struvite formation and collection have been used to remove phosphorus
from municipal waste treatment systems, the idea of promoting struvite formation and collection
is a relatively new concept for livestock wastewater treatment and nutrient management.
subirrigation. Application of irrigation water below the ground surface by raising the water table
to within or near the root zone.
Glossary 25
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
surface roughening (also called soil roughening). Increasing the relief of a bare soil surface
with horizontal grooves by either stair-stepping (running parallel to the contour of the land) or
using construction equipment to track the surface.
suspended growth or fixed film reactors. A configuration wherein the microorganisms
responsible for wastewater treatment are maintained in suspension within a liquid.
suspended sediment. Very fine soil particles that remain in suspension in water for a
considerable period of time without contact with the bottom. Such material remains in
suspension because of the upward components of turbulence and currents and/or by
suspension.
swales. Vegetated, open-channel management practices designed specifically to treat and
attenuate stormwater runoff for a specified water quality volume.
tailwaters. The channel or stream below a dam, often characterized by waters with low
dissolved oxygen. Many nonpoint source pollution problems in reservoirs and dam tailwaters
frequently result from sources in the contributing watershed (e.g., sediment, nutrients, metals,
and toxics).
tank. A watertight structure or container used to hold wastewater for such purposes as aeration,
equalization, holding, sedimentation, treatment, mixing, dilution, addition of chemicals, or
disinfection.
thalweg. In hydrologic terms, it is the line of maximum depth in a stream. The thalweg is the
part that has the maximum velocity and causes cutbanks and channel migration.
thinning. A tree removal practice that reduces tree density and competition between trees in a
stand. Thinning concentrates growth on fewer, high-quality trees; provides periodic income; and
generally enhances tree vigor. Heavy thinning can benefit wildlife through the increased growth
of ground vegetation.
three-zone buffer system. A technique for establishing a buffer, consisting of inner, middle,
and outer zones. The zones are distinguished by function, width, vegetative target, and
allowable uses.
tile drains. Pipe made of perforated plastic, burned clay, concrete, or similar material laid to a
designed grade and depth to collect and carry excess water from the soil.
26 Glossary
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
tillage. Plowing, seedbed preparation, and cultivation practices.
time-dosed pressure drip dispersal (flow equalization). A system configuration that includes
sufficient effluent storage capacity to allow for uniform flow to a subsequent component despite
variable flow from the source.
time-dosing. A configuration in which a specific volume of effluent is delivered to a component
according to a prescribed interval, regardless of facility water use.
topography. The shape and contour of a surface, especially the land surface, usually
characterized by slope, aspect, and elevation.
total maximum daily load (TMDL). A calculation of the highest amount of a pollutant that a
waterbody can receive and safely meet water quality standards set by the state, territory, or
authorized tribe.
total suspended solids. A measure of the suspended solids in wastewater, effluent, or
waterbodies, determined by tests for total suspended non-filterable solids.
turf. A surface layer of earth containing a dense growth of grass and its matted roots; sod.
turnouts (aka bleeders or cutouts). A drainage ditch that drains water away from roads and
road ditches.
urban forest canopy. The land surface area that lies directly beneath the crowns of all trees
and tall shrubs.
vegetated swales. A shallow drainage conveyance that has vegetative turf (typically grasses)
with relatively gentle side slopes, generally with flow depths of less than one foot.
vertical stability (degradation/aggradation). The ability of a stream system to maintain a
constant or balanced profile without deposition of sediment (aggradation) or incision
(degredation).
vortex rock weirs. A structure designed to serve as grade control and create a diversity of flow
velocities, while still maintaining the bed load sediment transport regime of a stream.
waste treatment lagoon. An impoundment made by excavation or earth fill for biological
treatment of wastewater.
Glossary 27
-------
Guidance for Federal Land Management in the Chesapeake Bay Watershed
water quality standards. State-adopted and EPA-approved ambient standards for
waterbodies. The standards prescribe the use of the waterbody and establish the water quality
criteria that must be met to protect designated uses.
weir. 1. A wall or plate placed in an open channel to measure the flow of water. 2. A W-Weir is
an in-stream structure constructed for the purpose of reducing shear stress on streambanks,
controlling the grade of the streambed and establishing fisheries habitat. W-Weirs are typically
constructed with two rock vanes on opposing sides of the stream channel forming the outside
legs and two opposing vanes in the center of the channel to complete the W-Weir.
weighted usable area (WUA). The total surface area having a certain combination of hydraulic
and substrate conditions, multiplied by the composite probability of use by fish for the
combination of conditions at a given flow.
wetland. An area that is saturated by surface or ground water with vegetation adapted for life
under those soil conditions, as swamps, bogs, fens, marshes, and estuaries.
windbreaks. A living barrier that usually includes several rows of trees, and perhaps shrubs,
located upwind of a farm, field, feedlot, or other area and intended to reduce wind velocities.
Windbreaks, also called shelterbelts, can reduce wind erosion, conserve energy or moisture,
control snow accumulations, and provide shelter for livestock or wildlife.
windrow. Logging debris and unmerchantable woody vegetation that has been piled in rows to
decompose or to be burned; or the act of constructing such piles.
WTR addition. The addition of iron-rich or aluminum-rich drinking water treatment residuals
(WTR) to soils to bind with phosphorus and reduce losses of phosphorus via leaching and
runoff.
28 Glossary
------- |