&EPA
Watershed Analysis
and Management (WAN)
Guide for States and
Communities
t
;ember 2003
Watershed
Analysis and
Management Project
-------
Foreword
Using a watershed approach provides a unique and effective way to assess the
environment, identify problems, establish priorities for preservation or restoration, and
implement solutions. The Watershed Analysis and Management (WAM) Program is an
effort to guide communities in the successful application of a watershed approach and
led to the development in 2002 of this Watershed Analysis and Management (WAM) Guide
for States and Communities.
The Environmental Protection Agency's (EPA) Office of Wetlands, Oceans, and
Watersheds (OWOW) and the American Indian Environmental Office (AIEO)
collaborated in 1997 on a joint project to develop a comprehensive WAM methodology.
The initial WAM approach was based on watershed planning efforts in the Pacific
Northwest, including the Washington State watershed analysis methodology for state and
private forest lands and the Northwest Forest Plan watershed analysis guide for federal
ownership. The concept was to extend existing capabilities to address a nationwide range
of ecological environments, project objectives, and watershed management issues at the
state, community, and tribal levels. With substantial support from the AIEO, a more
comprehensive approach was undertaken to include the additional issues of tribal cultural
and community values. The first product, Watershed Analysis and Management (WAM) Guide
for Tribes, was developed with a system development grant from OWOW to the Pacific
Watershed Institute, concurrent with pilot applications of the approach, through AIEO
grants, by tribes representing different ecological environments, objectives, and community
issues.
The Watershed Analysis and Management (WAM) Guide for Tribes was, published in September
2000. In addition, tribal WAM field training was developed and implemented with the
White Mountain Apache team, with the WAM Field Course Training Guidance produced
in 2001. A related effort, using a watershed approach to Total Maximum Daily Loads
(TMDLs), was undertaken with the Navajo Nation in Window Rock, Arizona, and the
guide Internal Capacity Building for Tribal TMDLs was produced in 2002. Simultaneously, the
WAM process was applied to state and community projects, including development of a
Watershed Quality Management flan. This plan serves as a template for incorporating quality
assurance into other watershed plans and documents.
-------
The Watershed Analysis and Management (WAM) Guide for States and Communities has
been strengthened by application of the WAM process in watersheds across the
United States. The guide incorporates knowledge gained through recent applications
of the WAM process to a large-scale county watershed project in Ohio and to a tri-
county coalition watershed project in the Snohomish River basin in Washington State.
Examples from these projects are included in the guide.
The WAM program has benefited from major program support and technical
contributions from OWOW and AIEO; Dave Somers, President, Pacific Watershed
Institute; Steve Toth, consultant and a principal contributor to both the Watershed
Analysis and Management (WAM) Guide for ^Tribes and the Watershed Analysis and Management
(WAM) Guide for States and Communities; the tribal pilot leads, Tammis Coffin, Latane
Donelin, Jonathan Long, and John Sims; and Paul Braasch, Environmental Coordinator,
Clermont County, Ohio, whose inputs made major contributions to this document.
Martin W Brossman, Project Officer
Watershed Analysis and Management (WAM) Program
page
-------
Acknowledgements
Contributors to this guide include (in alphabetical order):
Dr. Mike Barbour Christy Parker Nock
Martin Brossman Dr. Patricia Olson
Jean Caldwell Tom Ostrom
Dr. Shulin Chen Dave Somers
Jim Currie E. Steven Toth
Cygnia Freeland Curt Veldhuisen
Joanne Greenberg Karen Welch
Layout and Graphics:
Editing:
4 Point Design
Kay Hessemer
Diana Hoffer
We appreciate the generous funding provided by the EPA's OWOW and AIEO. Martin
Brossman, EPA's Project Officer, was invaluable in providing guidance and direct inputs
on the project. Terry Williams of the Tulalip Tribe (former director of AIEO) provided
the vision and continuing support necessary for the initial Watershed Analysis and Management
(WAM) Guide for Tribes. Finally, the insights from Tribes and other communities involved
with the projects were key to developing a flexible approach, and these projects provided
excellent examples of applying watershed analysis in different regions of the country.
This guide is patterned after a number of watershed analysis methods developed in
the Pacific Northwest. These efforts to promote watershed analysis have been an
invaluable source of information for this guide and include the Washington State
methodology developed for the Washington Forest Practices Board, the Federal guide for
watershed analysis produced by the Regional Ecosystem Office, and the Oregon watershed
assessment manual created for the Governor's Watershed Enhancement Board.
For more information on this WAM guide please contact:
E. Steven Toth
321 30th Avenue
Seattle, WA 98122
206-860-7480
thomtoth@nwlink.com
-------
page
IV
-------
Table of Contents
Introduction l
The Watershed Analysis and Management Process
Overview 19
Step 1: Scoping 25
Step 2: Watershed Assessment 45
Step 3: Synthesis 57
Step 4: Management Solutions 69
Step 5: Adaptive Management 85
Technical Modules
Community Resources CR-1
Aquatic Life AL-1
Water Quality WQ-1
Historical Conditions HC-1
Hydrology H-1
Channel C-l
Erosion E-l
Vegetation V-1
Glossary
-------
page
VI
-------
Acronym List
BIA Bureau of Indian Affairs
BOD Biochemical oxygen demand
BLM Bureau of Land Management
BMP Best management practice
cf S cubic feet per second
CWA Clean Water Act
DO Dissolved oxygen
EPA U.S. Environmental Protection Agency
ESA Endangered Species Act
FEMA Federal Emergency Management Agency
GIS Geographic Information System
HUC Hydrologic Unit Code
IAC Intergovernmental Advisory Committee
IFIM Instream Flow Incremental Methodology
NCASI National Council of the Paper Industry for Air and Stream Improvement
NMFS National Marine Fisheries Service
NOAA National Oceanic and Atmospheric Administration
NPDES National Pollutant Discharge Elimination System
NRCS U.S. Department of Agriculture Natural Resources Conservation Service
NWI National Wetland Inventory
PAHs Polycyclic aromatic hydrocarbons
PCBs Polychlorinated biphenyls
QA/QC Quality assurance/quality control
RCRA Resource Conservation and Recovery Act
RIEC Regional Interagency Executive Committee
RUSLE Revised Universal Soil Loss Equation
SCS U.S. Department of Agriculture Soil Conservation Service
Tl A Total impervious area
TMDL Total Maximum Daily Load
TSS Total suspended solids
USAGE U.S. Army Corps of Engineers
US DA U.S. Department of Agriculture
USDI U.S. Department of the Interior
USFS U.S. Department of Agriculture Forest Service
USFWS US. Fish and Wildlife Service
USGS U.S. Geological Survey
WAM Watershed Analysis and Management
WEPP Water Erosion Prediction Procedure
WFPB Washington Forest Practices Board
VII
-------
page
VIII
-------
4
4
4
4
4
4
4
4
4
4
4
4
4
4
4
4
4
4
4
4
4
4
4
4
4
4
4
4
4
4
4
4
4
4
4
4
4
4
4
4
4
4
4
4
4
4
4
Introduction
-------
The rivers, lakes, estuaries, and •wetlands in our communities are among our most precious
resources. We depend on them for clean •water to drink, to irrigate crops, to run
industries, to support fish and •wildlife, and to recreate •with our families. Yet, today most
of the Nation's major •watersheds have serious •water quality and habitat-related problems.
Traditionally, management of •water resources has focused on individual components of
the environment, such as drinking •water protection, •water quality analysis, or •wetland
preservation. Sources of pollution are also typically evaluated on a site-by-site basis.
Millions of dollars are spent to evaluate aquatic resources, conduct monitoring programs,
and develop restoration plans, yet these projects are rarely considered collectively.
Unfortunately, the health of many •watersheds continues to decline as a result of the
cumulative impacts from multiple land uses.
To address natural resource issues more
comprehensively, a •watershed approach can
be used to address problems across
administrative and political boundaries
(Figure 1). The •watershed approach
emphasizes partnerships between
communities and government agencies. This
coordination allows for the integration
of community values •with scientific
information about •watershed conditions.
Successful •watershed partnerships lead to
effective programs for improving •water
quality and restoring aquatic resources.
While each •watershed partnership must
address a unique set of social and
environmental issues, certain elements exist
that are common to successful •watershed
partnerships. The Watershed Analysis and
Box1. WhatisWAM?
Figure 1. A watershed approach focuses on addressing
water resource issues by river basins
Watershed
boundary
Floodplain
Stream
channel
The WAM process is
a well-defined, yet
flexible method to
credibly examine and
develop solutions to
watershed problems.
Management (WAM) approach outlined in this guide
describes these common elements in the form of practical
methods, tools, and examples that can help ensure effective
and efficient partnerships (Box 1).
The WAM process can be used by any organization or
partnership to help define goals and develop strategies
for improving •watershed conditions (Box 2). The WAM
process encourages the involvement of broad community
Introduction
-------
Box 2. WAM objectives
Characterize current and historical
watershed conditions
Evaluate the cumulative effects of
land management
Improve protection of community
resources
Promote management options that
protect watershed resources
Develop effective restoration projects
Design watershed-specific monitoring
programs
interests, including landowners, businesses, government agen-
cies, tribes, and other local groups. The WAM guide provides
ideas and tools for developing community involvement and
improving communication.
The WAM guide also describes practical methods for using
scientific information to credibly assess watershed conditions.
WAM encourages an ecosystem approach through the integra-
tion of different scientific disciplines. The WAM approach
also emphasizes the use of existing information such as maps,
photographs, monitoring data, and environmental reports as
the basis for planning efforts. Combining modern watershed
assessment techniques with the local knowledge and experience
of community members produces valuable insights about historical conditions, resource
trends, and restoration opportunities. Communities can use this information to develop
practical management solutions that protect and restore their important resources.
WAM is a flexible process that can be adapted to address a broad range of local
issues and watershed conditions (Box 3). WAM can also incorporate and enhance
existing environmental programs to use funds and personnel most efficiently. The
Box 3. WAM for novice and expert watershed groups
The WAM guide provides tools to help ensure effective watershed
improvements. Communities that are just beginning a watershed
approach to restoration can use WAM to help organize their
activities, define clear goals, and develop a strategy to achieve
those goals. The five-step process provides a road map for
addressing varied watershed issues and ensuring a long-term
and effective watershed improvement strategy. The technical
assessment modules provide a "cookbook" approach to help
assemble readily available information important to assessing and
evaluating watershed conditions.
More experienced watershed groups may benefit from the examples
and strategies used by other watershed groups around the country.
The WAM framework may also be a helpful way to organize disparate
watershed efforts and communicate watershed objectives. It may
also help to create a more interdisciplinary and holistic approach to
addressing watershed issues.
tools provided in the WAM process can
be used in any watershed to help ensure
that high quality information is collected
to support practical projects that will effec-
tively improve the health of the ecosystem.
Watershed management is a long-term
process that requires a strong commitment.
The benefits include not only restoring
the environment, but also improving the
sense of community. A watershed is more
than just a place—it represents a commu-
nity with important ideas and values about
using and protecting their environment.
page
2
Introduction
-------
WAM Design
The WAM design incorporates the following elements:
• Involvement of the local community.
• A focus on valued watershed and cultural resources.
• Integration of existing environmental programs.
• A comprehensive ecosystem approach.
• Practical and cost-effective assessment tools.
• Credible, interdisciplinary scientific methods.
• Emphasis on long-term commitment to watershed management.
Ecosystem Approach
The WAM process uses an ecosystem approach to better understand watershed conditions
and the ecological processes that influence them. An ecosystem approach emphasizes
the workings and interactions of the ecosystem resources, such as fish, water quality, and
community resources, and processes, such as hydrology, erosion, and vegetation growth.
This approach contrasts with traditional environmental assessments that emphasize the
understanding of individual components or interactions among a small number of
components.
The WAM process considers key ecosystem components and the interactions among
physical and biological processes (Figure 2). Important connections among watershed
components can be evaluated using the findings of the watershed assessment.
WAM Participation
The watershed group is optimally led by community representatives who have an interest
in watershed issues. Environmental professionals are helpful to implement the assessment
and carefully evaluate issues in a credible and defensible manner. Long-time residents
can provide local knowledge about changes in watershed conditions. Larger and more
complicated assessments may also use a facilitator to ensure effective and organized
discussion in a neutral atmosphere.
Ultimately, community-wide involvement in the WAM process is important to make long-
term changes in watershed management, but each watershed group will need to determine
Introduction
-------
Figure 2. Key ecosystem components
DELIVERED
TO STREAM
I Cattle Grazing Cattle grazing is one of many land
use activities that can be culturally and economically
important to local communities. Grazing can impact natural
vegetation, erosion rates, and water quality
| Physical Setting Soils from various bedrock materi-
als have different erosion potentials and support differ-
ent types of vegetation.
PSJ Climate Weather patterns and intensity of rainfall are
factors driving erosion processes and affecting vegeta-
tion patterns.
^j Topography Slopes are a significant factor influenc-
ing erosion and accessibility for grazing and timber
harvest. Slope aspect is also important in determining vege-
tation patterns.
I Vegetation Type Vegetation communities provide
many economic resources (e.g., timber) and cultural
resources (e.g., medicinal plants). Reduced vegetative cover
or a change in species composition can lead to increased lev-
els of soil erosion.
I Riparian Zones Riparian zones are a critical compo-
nent of the watershed, providing habitat and ecological
functions (e.g., sediment buffer strip, stream shading, and
nutrient input to streams).
PV Water Quality Water quality conditions dictate the
type and status of aquatic life. Sediment from elevated
erosion levels can eliminate habitat and introduce other pol-
lutants to the water column. Increased water temperatures
can degrade habitat for aquatic species.
§j Aquatic Life Fish are often a key ecological, cultural,
and economic resource. Aquatic species are also good
indicators of watershed ecosystem health. Impacts through-
out the watershed are reflected in aquatic habitat conditions.
•• Stream Channel The stream channel is a dynamic
feature of the watershed with conditions that are
defined by a combination of natural physical characteristics.
Land-use impacts (e.g., dams, channel dredging or straight-
ening) and natural events (e.g., floods) can significantly
degrade channel conditions, reducing or eliminating aquatic
habitat. Changes in sediment delivery can modify the com-
position of the stream bed. Loss of streamside vegetation can
increase bank erosion.
page
4
Introduction
-------
the best pathway. For example, the development of watershed partnerships may occur
in several stages (Box 5)- Creating partnerships to reach consensus and protect valued
resources takes time.
Box 5. The Prairie Band of the Potawatomi partnership approach
The Prairie Band of the Potawatomi first identified watershed concerns in Big Soldier
Creek using internal staff and consultation with tribal members. Partnerships with
the U.S. Department of Agriculture (USDA) Natural Resources Conservation Service
(NRCS), Kansas State University, Haskell Indian Nations University, and Royal Valley
High School allowed the tribe to characterize watershed conditions and initiate
streambank stabilization projects.
Since the watershed area is much larger than the reservation and because of
"checkerboard" ownership within the reservation, a broader program of public
outreach was initiated. A watershed working group was established with the larger
community to create a comprehensive resource management plan. Building these
partnerships will allow access to more resources, improve coordination, and develop
support and cooperation from tribal members, private citizens, and public agencies.
WAM Time-frames and Resource Needs
The time-frame and resources needed for the WAM process are related to the objectives
for conducting the analysis. General planning may require only a few weeks or
months. Environmental impact statements or Total Maximum Daily Load (TMDL)
plans, however, may require months or years to complete. The actual time and costs
of initiating and completing the WAM process will vary depending on the following
factors:
• Size of the watershed.
• Availability of staff and resources.
• Amount and accessibility of existing data and information.
• Complexity of the ecological and management conditions in the watershed.
• Amount of work needed to have confidence in the assessment.
Introduction
-------
Levels of Assessment
Level 1 assessment
Level 1 assessment relies primarily on existing information such as natural resource
maps and past environmental reports. Level 1 assessment is a broad-based information
gathering effort that can reveal important insights about watershed functions and
interactions. Level 1 assessment is qualitative and may result in lower levels of certainty
or confidence in the assessment results.
Level 2 assessment
In Level 2 assessment, experienced analysts utilize more data collection, quantitative
assessment tools, field surveys, and computer-based models to provide a higher level of
certainty or confidence in the assessment results. A Level 2 assessment requires more
time and resources than does a Level 1 assessment and may follow a Level 1 assessment
when results are indeterminate or vague.
Quality Assurance/Quality Control
Box 6. Logic tracking
Logic tracking refers to the documentation of the
thought process, decisions, and results of each
step of WAM. There are a number of tools in WAM
to assist in logic tracking:
• Lists of critical questions.
• Forms provided in each module to document
vital information.
• Map and data requirements in reports.
• Review of key watershed issues.
Logic tracking also provides quantitative and quali-
tative information that can be used to determine the
certainty or confidence level of the assessment
results. Assessment methods, data sources, data
quality, assumptions of the assessment, and limita-
tions of the results are all documented.
The intent of the quality assurance and quality
control (QA/QC) procedures embedded in the WAM
process is to reduce potential errors in the watershed
assessment, ensure the effectiveness of management
solutions, and provide repeatability and accountability.
Seven elements for meeting QA/QC objectives are
included:
1. Joint technical and policy discussion of key
watershed issues.
2. Credible scientific assessment methods.
3- Explicit treatment of uncertainty.
4. Identification of key assumptions.
5. Logic tracking to achieve accountability (Box 6).
6. Direct link between watershed assessment and
management solutions.
7- Adaptive management feedback through
monitoring.
page
6
Introduction
-------
WAM Process
The WAM approach consists of five steps that lead the watershed group through issue
definition, assessment, management planning, and monitoring (Figure 3)- This guide is
intended to be a basic reference for collecting important watershed
information. For more detailed analyses, the document lists possible
approaches and provides additional technical references. In many
situations, it may be infeasible or undesirable to conduct all steps
and analyses described in this document. The WAM process
should be adapted to integrate existing environmental programs and
address priorities unique to each community.
Scoping
In the Scoping step, the watershed
group will determine the issues to be
addressed through the WAM project.
The Scoping process also determines
how the community will participate
in the project. Community-wide
participation is desirable as it provides greater input on watershed
issues and helps ensure that effective management changes will be
implemented.
Watershed Assessment
A set of technical modules provides guidance for
assessing the major ecological components of a
watershed in a structured and coordinated manner
(Box 7). Collectively, the modules are designed to
provide a holistic view of the watershed system. The products from
these modules are designed to provide compatible information for
use in Synthesis.
Figure 3. WAM five-step process
C steP1
SCOPING
Determine watershed issues
and project goals
Enhance community participation
C
WATERSHED ASSESSMENT
Determine scope of assessment
Conduct science-based analysis
Promote interaction among analysts
Step 3
SYNTHESIS
Combine information about the
ecosystem
Summarize key findings
C
MANAGEMENT SOLUTIONS
Develop management options
Create management plan
( Steps
ADAPTIVE MANAGEMENT
Monitor watershed conditions
Evaluate management plan
Introduction
-------
Box 7. Technical modules
Resource modules identify important
resources and determine their sensi-
tivity to changes in environmental
conditions:
• Community Resources
• Aquatic Life
• Water Quality
• Historical Conditions
Process modules evaluate the effects
of land uses or management practices
on the environment:
• Hydrology
• Channel
• Erosion
• Vegetation
Synthesis
The objective of Synthesis is to combine
knowledge gained about individual
components of the watershed into a
comprehensive understanding of watershed
issues. Synthesis focuses the assessment on the interactions among
land use activities, watershed processes, and resource conditions.
Synthesis is an interdisciplinary exercise and may include both
technical analysts and community representatives who participated in
Scoping. Synthesis requires participants to look beyond their respective
areas of expertise and the analyses conducted in individual modules.
Synthesis results in a number of products designed to take the
information generated from the technical modules and create an
understanding of the watershed as a system—in other words, to develop the "watershed
story." These products document the risks to watershed resources and form the
foundation for developing management solutions.
Management Solutions
In the Management Solutions step, the information generated through
Watershed Assessment and Synthesis is used to develop specific management
options, monitoring needs, and restoration priorities. A management plan is
developed with a number of management options to provide flexibility for
implementation by the community.
Adaptive Management
The uncertainties in our understanding of natural ecosystems and in the
effectiveness of management practices require the use of Adaptive Management.
Adaptive Management is the process by which new information about the
health of the watershed is incorporated into the management plan. The
Adaptive Management section provides guidelines for developing research and monitoring
programs to address gaps in information and to measure the effectiveness of management
activities.
page
8
Introduction
-------
Examples of WAM Applications
Ideally, the WAM process should be pursued at the initiation of a watershed project.
Experience has shown, however, it can be a valuable tool in many related applications.
Some of these applications are summarized here; all involved funding or expertise provided
by the WAM project. They include an ongoing large-scale, long-term county watershed
project in Ohio, a tri-county coalition watershed project in the Snohomish River Basin
in Washington State, and development of a watershed field training program. The WAM
method has been refined with its application to the development of such watershed plans
and training.
Clermont County XLC Project
The U.S. Environmental Protection Agency (EPA) established Project XL, eXcellence
and Leadership, to work with interested project sponsors from four categories (facilities,
industry sectors, governmental agencies, and communities) to determine whether common
sense, cost-effective strategies can replace or modify specific regulatory requirements
to produce and demonstrate superior environmental performance. Clermont County,
Ohio, is participating in Project XLC (for communities) to develop alternative pollution
reduction strategies, focusing on the watershed of the East Fork of the Little Miami River.
WAM provided the necessary well-defined, rational process and quality controls for this
project.
The project addresses multiple water quality, land use, and economic development issues
in the County, while developing a multi-year master work plan for implementation. The
work plan includes identifying watershed issues, assessing water quality impacts from
existing and future land uses, and developing the appropriate management approaches to
prevent water quality impairment while promoting economic development. The XLC
Team includes Clermont County, Ohio, The State of Ohio, and XL Co-leads from EPA's
Region 5 and EPA Headquarters.
Since XL projects involve replacement or modification of specific regulatory requirements
to produce and demonstrate superior environmental performance, they require especially
carefully documented processes and quality controls. An expert on the WAM process
and quality assurance was given a key role with the team. A Watershed Quality
Introduction
-------
Management Plan was developed, based on the WAM process, to meet their needs.
The following figures are illustrative examples from the Watershed Quality Management
Plan. The complex organization of project manager, regulatory agencies, stakeholders,
and consultants is shown in Figure 4. The parallel nature of the Project Manager and QA
Manager roles is of key importance to ensure objective oversight.
Figure 5 shows the interaction of the Clermont County XLC project participants within
the WAM process. The total plan for the multi-year Clermont XLC project is based on
the five phases of the WAM process with tasks and products defined under each phase.
This has proven valuable in communications as well as in effective project planning and
control. Figure 6 shows how the WAM process was used to define the activities and
milestones for the lifetime of the Clermont project.
Figure 4. Key partnerships of the XLC project in Clermont County, Ohio
Appropriate
Agency
Project Manager
From Pool of
Agencies with
Regulatory Authority
(Issue-Dependent)
Project XLC
USEPA Consultation
Team
Clermont County
Stakeholder
Committee
Key Partnerships:
Project
Management
__ Quality
Assurance
Clermont County
XLC
Project Manager
Contractors and
Consultants
Task Managers
Appropriate
Agency
QA Manager
From Pool of
Agencies with
Regulatory Authority
(Issue-Dependent)
Project XLC
QA Consultation
Team
Clermont County
XLC
QA Manager
Contractors and
Consultants
QA Coordinators
Clermont County
Science Advisory
Committee
Lines of
Communication
page
10
Introduction
-------
Figure 5. The WAM process for the Clermont County XLC project
Clermont County, OEPA, and
Appropriate Local, State, and
National Organizations
Scoping:
Identification of Issues
/ Project XLC \
4 \ USEPA Consultation Team )
Stakeholder
Committee
Clermont County, Contractors
and Consultants
Watershed Assessment:
Quality Requirements, Data
Collection, Data Analysis
Appropriate Agency
and Consultation Team
QA Oversight
Corrections
Needed
/ Appropriate Local,
( State, and National
^\ Organizations s
Clermont County, Contractors
and Consultants
Synthesis:
Data Interpretation, Integration, and
Recommendations for Management
v Prescriptions ,
Data Unacceptable
Data Acceptable
Appropriate Agency
and Consultation Team
QA Oversight
Clermont County, OEPA, and
Appropriate Local, State, and
National Organizations
Management Prescriptions:
Decision Making
More Information
Needed
Project XLC
USEPA Consultation Team
No Regulatory
Flexibility Issue
Regulatory Flexibility
Requested
Stakeholder
Committee
USEPAand
Other Agencies
Review
Denied-
Clermont County, OEPA, and
Appropriate Local, State, and
National Organizations
Adaptive Management:
Monitoring and Evaluation
T
Objective Achieved to Address Issues
Evaluate New Options
Introduction
11
-------
Figure 6. Proposed time line for Clermont County XLC project
Note: "X" = time period in which major effort occurs
"—" = time period in which minor effort occurs
Activities snd
Milestones
Scoping
Identify critical issues
Establish project objectives
stakeholders
Determine roles and
responsibilities
Determine data needs, tools
Review requirements
Prepare water quality
sampling work plan
Procure contractors/
consultants
Develop modeling system
Approve Phase 1 Project
Agreement
Determine schedule
Prepare Watershed QMP
Assessment
Acquire data
Analyze data
Review data and prepare
data summary reports
Pre-Project
Agreement
Activity
X
X
Y
X
X
X
X
X
X
X
X
2000
Q3 Q4
X X
X X
V
X —
X X
X
X X
X X
X
X X
X
2001
Q1 Q2 Q3 Q4
X X
—
— —
X X
X
— X — —
X X X X
—
X — —
X
X X X X
X
2002
Q1 Q2 Q3 Q4
— —
—
X X
X
— X — —
—
XXX
X X X X
X
2003
Q1 Q2 Q3 Q4
— —
—
X X
X
— X — —
—
XXX
X X X X
X
2004
Q1 Q2
— —
—
X X
X
— X
—
page
12
Introduction
-------
Figure 6. (continued)
Activities and
Milestones
Synthesis
Review data summaries and
other information
Evaluate action options for
each issue
Prepare watershed issue
summaries
Management Prescriptions
Develop Watershed Action
Plan with recommendations
for actions to address the
issues
Stakeholders review and
approve
Prepare draft Watershed
Management Plan
Regulatory flexibility
considerations by
appropriate agencies
Complete Watershed
Management Plan
Adaptive Management
Design monitoring program
Monitor actions implemented
Evaluate effectiveness of
actions
Adjust the Plan
Pre-Project
Agreement
Activity
2000
Q3 Q4
2001
Q1 Q2 Q3 Q4
X X
X X
—
X
2002
Q1 Q2 Q3 Q4
— —
— —
X
X X
X
X X
X X
X
2003
Q1 Q2 Q3 Q4
— —
— —
—
X X
X X
X
2004
Q1 Q2
— —
— —
—
X
X —
Introduction
13
-------
Marshland Watershed Assessment
The Snohomish River basin, located just north of Seattle, Washington, is the second
largest watershed draining to Puget Sound (1,856 square miles). The watershed supports
significant populations of native fish important to commercial and recreational interests,
including coho, chinook, chum, and pink salmon; steelhead, rainbow, cutthroat, and
bull trout; and mountain whitefish. The Marshland Watershed Assessment documents
historical changes and current environmental conditions. Two species, chinook salmon
and bull trout, have been listed as threatened under the Endangered Species Act (ESA).
In response to the ESA listings, the State of Washington is developing a statewide
salmon strategy that includes regional and watershed-specific recovery plans. Numerous
governmental and non-governmental organizations are represented at the regional level
through a tri-county coalition. Policy and technical committees have been formed to
develop comprehensive watershed management plans that will lead to the recovery of
salmon populations. These plans will address many factors affecting fish populations,
including habitat conditions, land use development, artificial hatchery production, and
harvest.
The Marshland watershed, within the Snohomish River basin, was chosen to serve as
a potential template for other watershed plans within the basin.The WAM framework
developed through the EPA is being used to help ensure community participation, an
ecosystem approach with defensible technical assessments, and management plans tied
directly to the results of the watershed assessment.
The Marshland Watershed Assessment utilized the WAM process to help guide data
collection and work with the local community to identify environmental issues and
potential solutions. Scoping, the first step in the WAM process, addresses community
involvement, problem identification, and project goals. Based on discussions with
the Marshland community, Snohomish County, and state and federal agencies, four
environmental issues were identified: preserving endangered salmon, protecting homes
and agricultural lands from flooding, addressing urban growth impacts, and improving
water quality.
page
14 Introduction
-------
Watershed Assessment and Synthesis are the second and third steps, respectively, of the
WAM process. The Marshland Watershed Assessment documents historical changes
and current environmental conditions (Figure 7) - Major ecological components of
the watershed were evaluated using existing information, such as natural resource
maps, environmental reports, and monitoring data. The Level 1 assessment relied
on information from experts in hydrology, geology, fish biology, ecology, and water
quality. Synthesis was used to integrate the assessment results and summarize important
findings.
The Marshland community is now conducting the fourth step of the WAM process,
evaluating various Management Solutions to their environmental issues. Specific
solutions, such as changes in land use practices and restoration of aquatic habitat,
are being discussed with the Marshland community and other watershed stakeholders.
Further work will be required in this step of the process to evaluate the feasibility
of promising or preferred alternatives and to develop a comprehensive watershed
management plan. The last step of the WAM process, Adaptive Management, will
address the need to monitor conditions and refine the watershed plan as environmental,
economic, and social conditions change over time.
Utilization of WAM as a Basis for Watershed Training
The structured approach of the WAM process in well-defined steps and modules also
makes it effective as a foundation for watershed training. In order to facilitate use of the
watershed approach by tribes with limited experience, the WAM tribal guide was used
to develop a watershed field training course. A training guide describes the week-long
training course that was designed for a particular watershed on the White Mountain
Apache tribal lands in the mountains of eastern Arizona. The training guide, WAM
guide, and a training video are now available for use in training.
Figure 8 illustrates the units of instruction, the means of instruction, and the
relationship of each unit to the WAM guide. Note that the participants are first
introduced to the WAM guide, familiarizing them with the WAM process. The
participants are then trained in map interpretation, field investigation, geologic analysis,
etc. through a combination of lectures and field trips.
Introduction 15
-------
Figure 7. Maps illustrating changes in land use and wetland communities in the Snohomish River
basin for the evaluation of watershed restoration options (Collins 2000)
A.
I
Snohomish
-1860
WETLANDS /
Estuarine Emergent
Estuarine Scrub-Shrub
Riverine Tidal Foisted
Riverine-Tidal Scrub-Shrub
Palustrine Scrub-Shrub
I
h
Forested Floodplain
Forested Terrace
Tidal Flats
• Channel
0 I 2 3 4 s Kilometers
Snohomish
1895-1911
WETLANDS /
Estuarine Emergent
Esluarirte Scrub<>hrub
Riverine Tidal Forested
Riverine Tidal (Logged Forest)
Riverine-TJdal Scrub-Shrub
Palustrine Scrub-Shrub
Snohomish
1941-1953
WETLANDS
Estuarine Emergent
Estuarine Scrub-Shrub
Riverine Tidal Forested
• Rlwrlrw-Tlrlal Scrub-Shrub
Palustrine Scrub-Sliul.1
page
16
Introduction
-------
Figure 8. Overview of WAM watershed training program
Unit
WAM Introduction
Scoping
Assessment
Map Interpretation
Field Investigations
Aerial Photo
Interpretation
Geologic Analysis
Channel
Soils
Ecoregions & Land
types
Erosion
Hydrology
Water Quality
Synthesis (focus on
riparian conditions)
Management Plan
Development
Means of Instruction
Classroom discussion of introduction
materials
Discussion of sample watershed issues
Through units below
Lecture, measurements, and map reading
activities
Four field trips to different project sites
Compare changes in land feature through
time
Lecture, map interpretation, and sample
identification
Lecture, field measurements of cross-
sections and pebble counts
Lecture, texture laboratory, game,
interpretation of soil survey on field trip
Lecture and map interpretation
Lecture, photo interpretation, game
Lecture, climate activity, game, stream gaging
demonstration
Field sampling of water quality, water
quality analysis with Piper diagram
Lecture and game
Group project and presentation
Relationship to WAM
Introduction and Overview
Scoping
Watershed Assessment
Basic skills required for Level 1 analysis;
Channel Module
Demonstration of Level 2 analysis techniques;
discussion of Adaptive Management at project
sites
Basic skills required for Level 1 analysis;
Historical Conditions Module, Erosion Module,
Channel Module
Erosion Module
Channel Module
Erosion Module
Erosion Module; Vegetation Module
Erosion Module
Hydrology Module
Water Quality Module
Synthesis; Channel Module, Aquatic Life Module,
Community Resources Module
Synthesis, Watershed Assessment, and
Management Solutions
Introduction
17
-------
References
Collins, B.D. 2000. Mid-19th century stream channels and wetlands interpreted from
archival sources for three north Puget Sound estuaries. Report prepared for
the Skagit System Cooperative, Bullitt Foundation, and the Skagit Watershed
Council.
page
18
Introduction
-------
The Watershed Analysis
and Management Process
-------
Overview
-------
This portion of the guide describes the methods and tools for
implementing the WAM process. The guide is written primarily for
environmental professionals who wish to implement a WAM process.
The WAM process comprises five general steps (Figure 1).
Detailed guidance on conducting each step is provided in the five
corresponding sections of this manual. The following paragraphs
provide an overview of how WAM can be used to meet watershed
management objectives. The five steps of the WAM process provide
a logical progression for conducting an assessment with community
involvement, defensible scientific analysis, and credible management,
monitoring, and restoration plans to address watershed impacts.
The WAM process also allows sufficient flexibility to accommodate
varying levels of community participation, technical assessment, and
management plan development. Box 1 lists definitions for some
commonly used terms in the WAM guide. A glossary at the end of
the guide provides definitions for a complete list of technical words
and jargon.
Figure 1. WAM five-step process
C
SCOPING
Determine watershed issues
and project goals
Enhance community participation
C
WATERSHED ASSESSMENT
Determine scope of assessment
Conduct science-based analysis
Promote interaction among analysts.
Step 3
\
SYNTHESIS
1 Combine information about the
ecosystem
• Summarize key findings V
Box 1. Definitions for terms commonly used in the WAM guide
Community resource: an environmental asset that has
important cultural and economic value for the people of
the region (e.g., drinking water, agricultural land, fish,
wildlife).
Delivery potential: the likelihood that a hazardous input
will be transported to a community resource.
Hazardous input: any element of the ecosystem that can
affect a community resource (e.g., sediment, nutrients,
heat).
Resource sensitivity: the responsiveness or
susceptibility of the environmental asset to hazardous
inputs.
Watershed process: a natural system of interactions in
the environment (e.g., water movement, erosion, nutrient
cycling).
MANAGEMENT SOLUTIONS
1 Develop management options
• Create management plan
C
ADAPTIVE MANAGEMENT
' Monitor watershed conditions
> Evaluate management plan
Overview
page
19
-------
While this guide advocates a structured and comprehensive approach to watershed
assessment, it is important to recognize that watershed-based management is an iterative
process that requires an ongoing effort of assessment, planning, monitoring, and
communication. Environmental programs that address one or more of these steps may
already exist. WAM can help to evaluate and refine these programs to most effectively
address watershed-scale problems. Resource management information will need to be
collected and analyzed over the long term to provide a sufficient understanding of
watershed conditions. It may also take many years of building partnerships to create
and implement a watershed management plan for public and private land within the
community.
Scoping
ft
The Scoping process helps to organize and focus the
leadership of small and large watershed groups on priority
watershed issues. The WAM guide provides guidance on
developing a goal-oriented strategy, producing realistic action
plans, addressing financial needs, and implementing priority
projects. It will also help the watershed group decide
on how to strategically engage and interact with the local
community. Effective changes in watershed management usually cannot happen without
broad community involvement and support. The challenges of community participation,
however, may necessitate a phased WAM approach that allows for background data
collection and more communication time to better address inevitable issues of jurisdiction,
overlapping authorities, and risk management.
The Scoping section also discusses important project and information management needs.
The WAM process generates a great deal of information that can be valuable when
considered in a long-term management framework. It is important to create a process
for consistently collecting, storing, and displaying watershed data through tools such as
computer databases and geographic information system (GIS) map layers so that results can
be summarized and communicated effectively.
page
20
Overview
-------
Watershed Assessment
The Watershed Assessment step provides an opportunity to collect
information about key ecosystem processes that can be used to
interpret watershed conditions and help guide restoration efforts. This
section provides examples of common watershed issues, the technical
modules that typically relate to each issue, and the critical questions
within each module that may be applicable. This information can
be used to focus the assessment on specific parts of the ecosystem.
Consultation among community representatives and the technical team is encouraged
to make sure that the appropriate information is collected while maintaining an
interdisciplinary and comprehensive assessment. The section also provides guidance on
collecting important background information and managing the assessment process.
The Technical Modules are organized into eight sections to evaluate various aspects of the
ecosystem. They contain a description of methods and tools that can be customized to
address the watershed issues and project goals identified in Scoping. The Community
Resources, Aquatic Life, Water Quality, and Historical Conditions modules address the
current and historical distribution and condition of important resources in the watershed.
The Hydrology, Channel, Erosion, and Vegetation modules address the physical and
ecological setting of the watershed and the effects of land use practices over time.
Separating the assessment into technical modules provides a structured approach to
ecosystem analysis and the flexibility to focus on critical watershed resources and processes.
Critical questions within each technical module provide additional flexibility to refine the
analysis and use only the applicable tools and methods. A table at the beginning
of each module lists the critical questions along with the
kinds of methods or tools available to answer the critical
question. Depending on the objectives of the analysis,
some modules or critical questions may not be necessary to
complete a watershed assessment. Alternatively, modules may
be combined into one analysis effort (Box 2).
The methods and tools described in each technical module
are divided into two categories: Level 1 and Level 2
assessment. Any combination of Level 1 and 2 assessment
Box 2. Combining modules
Combining tools and methods from multiple mod-
ules can provide an efficient and effective assess-
ment process. The following combination of mod-
ules may be desirable:
• Community Resources/Historical Conditions
• Erosion/Channel
• Channel/Aquatic Life
• Hydrology/Channel
Overview
page
21
-------
Box 3. Potential objectives of a Level 1 assessment
• Summarize general watershed characteristics
• Describe key watershed issues
• Identify important gaps in information
• Prioritize further assessment or monitoring needs
can be conducted depending on the objectives of the
assessment. Level 1 methods and tools rely on existing
information to summarize and evaluate the current state of
knowledge about the watershed (Box 3). These methods
and tools are described in each module as a series of steps
to provide useful products and a comprehensive assessment.
This "cookbook" approach can be helpful for users who have
limited resources or limited experience with watershed-scale
assessments. Level 1 assessments generally require a few weeks of work for each module,
but the actual time will depend on factors such as the watershed size and availability of
data. Box 4 provides examples of the products of a Level 1 assessment.
Box 4. Summary of possible Level 1 technical module products
Resource Modules
Community Resources
• Locations of community resources
• Map of community resource sensitivities
• Ecological needs of each resource
• Land use impacts on each resource
Aquatic Life
• Map of species distribution
• Assessment of habitat conditions
• Map of habitat sensitivities
Water Quality
• Locations of beneficial uses
• Applicable water quality criteria and standards
• Potential sources of pollutants
• Map of water quality sensitivities
Historical Conditions
• Historical timeline
• Trends in resource conditions
• Map of historical sites
Process Modules
Hydrology
• Climate summary
• Characterization of runoff processes
• Characterization of stream runoff
• Potential land use impacts (e.g., dams, dikes, urban and rural
development, irrigation, grazing)
Channel
• Map of stream network
• Channel classification (stream channel gradient and confine-
ment, sinuosity, or other physical features)
• Map of channel types
• Summary of land use impacts
Erosion
• Summary of geology and soils
• Relationship between land use practices and erosion
• Map of erosion hazards
Vegetation
• Map of vegetation communities, riparian areas, and wetlands
• List of threatened and endangered plant species
• Summary of historical changes in vegetation and land use
impacts
page
22
Overview
-------
Box 5. Potential objectives of a Level 2 assessment
The Level 2 methods and tools are more technical and typically require experienced
analysts (Box 5). The Level 2 section of each module provides a "menu" of
approaches that includes for each approach a general
description, guidance on its appropriate use, and
technical references for more detailed information.
The purpose of the Level 2 section is to provide a
list of options for a detailed watershed assessment
rather than specific directions on how to implement
the approach. A Level 2 assessment often requires
field surveys and a time frame of several months to
complete. The methods also require a good deal
of professional judgement to evaluate the applicability of the tools, understand the
limitations of the methods, analyze the data, and objectively interpret the results.
• Supplement existing watershed data to test hypotheses
• Establish cause-and-effect relationships among manage-
ment activities and watershed conditions
• Delineate specific areas that require special management
• Establish monitoring requirements and criteria
• Identify cost-effective restoration projects
While the modules are separated to provide more flexibility in the assessment,
interdisciplinary discussion and shared data collection among technical modules
is an important component of the assessment (Box 6). The Synthesis step provides
a formal setting for integrating information on various aspects of the ecosystem into
Box 6. Icons
Water Quality
Channel
Vegetation
This icon appears in the
margins of the technical
modules to highlight parts of
the assessment for which
information exchange and
consultation with other mod-
ule analysts may be helpful.
a holistic understanding,
but integration also occurs
during the Watershed
Assessment. A great deal
of interaction among
technical module analysts
is necessary to further
understanding of complex,
interconnected ecosystem
processes.
Synthesis
The Synthesis section describes a process to integrate the results of the Watershed
Assessment and to summarize important findings. Synthesis
provides an opportunity for formal interaction among different
scientific disciplines to provide a more comprehensive picture of
the watershed. This part of the WAM process can also provide
Overview
page
23
-------
an opportunity for interaction between technical and non-technical participants to
improve understanding of watershed conditions and potential interactions among land
uses, watershed processes, and community resources. In addition, Synthesis may be used
to help evaluate risks to important resources.
Management Solutions
The Management Solutions section provides guidance on integrating technical
^[^ information about watershed concerns into an accessible format that
'"*-' ^^^^ can be used to evaluate and develop management options and to create
^^^^ a management plan. Management options may include changes in land
use activities, implementation of monitoring plans, or development of
restoration plans. The development of management options is generally more effective
with community-wide participation, but local, state, or federal agencies may have the
ability to implement some management options on their own.
Adaptive Management
The Adaptive Management section describes the role of research and monitoring
in addressing gaps in information and ensuring the effectiveness of
management solutions (Box 7). The uncertainties in our understanding
of natural systems and in the effectiveness of management actions
require the use of adaptive Box 7 Monitoring objectives
management. Guidance is provided
to identify specific objectives for new
scientific research or development of
monitoring plans. This information
can be invaluable for developing
defensible, long-term watershed
management plans.
• Implementation: Evaluate whether
management plan was properly
completed
• Effectiveness: Examine whether
the proposed changes resulted in
desired effects
• Validation: Confirm assumptions,
evaluate predictions, and research
trends
page
24
Overview
-------
Step i: Scoping
-------
Scoping
-------
Introduction
Watershed restoration efforts can vary from site-specific projects using local volunteers
to regional, multi-governmental partnerships. The Scoping process helps to organize the
leadership of small and large communities and focus them on priority watershed issues.
The WAM guide provides guidance on developing a goal-oriented strategy, producing
realistic action plans, addressing financial needs, and implementing priority projects. It
•will also help the •watershed group decide how to strategically engage and interact •with
the local community. This engagement •will be critical to effectively improve •watershed
conditions.
Depending on the needs of the •watershed group, each step of the Scoping process can
be addressed by following the ordered list of actions or specific actions can be considered
individually. In either case, Scoping is by nature an iterative process, and the •watershed
group •will •want to periodically revisit the issues addressed in this section.
Scoping Process
Step Chart
Procedure
The objectives of the Scoping step are as
follows:
• To organize leadership for the WAM
process.
• To determine key •watershed issues.
• To develop a strategy that addresses
priority •watershed issues.
• To determine staff and funding needs.
• To determine Watershed Assessment
requirements.
• To enhance community participation.
Review group organization
and leadership
Determine watershed boundaries
and key issues
Develop WAM goals and strategy
Consider funding and
other resource needs
Enhance community participation
Scoping
page
25
-------
Step 1. Review group organization and leadership
Since each watershed group will have a unique set of people and issues to address,
this section cannot provide a specific blueprint for group organization and leadership.
Instead, this step identifies important elements to consider in the development and
growth of any watershed group (Box 1). The watershed group will need to specifically
determine the lines of responsibility and authority for managing various aspects of the
watershed program.
Box 1. Choosing WAM project goals
Smaller, less intensive efforts to evaluate watershed conditions can
yield important insights about watershed functions and interactions.
This type of assessment can help meet a variety of goals:
• Educating the local community about key watershed issues.
• Summarizing current information on watershed conditions.
• Identifying important gaps in knowledge.
• Organizing and prioritizing future actions.
• Conducting pilot projects for monitoring and restoration.
Involving the local community may be particularly important when
conducting WAM with limited resources. Staff can often be
supplemented with help from local citizens and professionals at
county, state, or federal agencies.
Larger, more intensive WAM efforts can provide a more rigorous
evaluation to identify cause-and-effect relationships in watershed
conditions using science-based assessments. More detailed
assessments can help meet goals such as the following:
• Educating and engaging varied interest groups in the watershed.
• Evaluating and supplementing existing watershed information.
• Identifying specific areas that require special management.
• Establishing watershed-specific standards for improved management.
• Planning cost-effective monitoring and restoration projects.
Larger assessments will require more financial and staff resources
to manage the process. Soliciting funds from various state and
federal grants may be an important part of this process.
The size of the organization necessary to
achieve watershed restoration objectives is
typically proportional to the size of the
watershed area. A small watershed
group working in a large watershed
area may want to consider focusing
efforts on a smaller area, such as the
watershed of a major tributary. Large
watersheds generally require a more
complex organization to address varied
land management issues and resource
conditions.
Most watershed partnerships will involve
a number of different interest groups.
It will be important to ensure adequate
representation for all groups likely to be
affected by the watershed management
process. However, the social and
political dynamics may require a staged
approach starting with a small group of
like-minded participants and eventually
expanding to become more inclusive
of all watershed interests. Ultimately,
resolution of watershed management
issues will depend upon the collaboration
of all interested parties.
page
26
Scoping
-------
A community-driven watershed group will typically have better success engaging key
local landowners than will outside agencies or specific interest groups. Whether the
watershed group is just starting out or has a long history, establishing and maintaining
communication with key landowners or interest groups will be a vital, on-going task to
meet watershed restoration objectives.
The organization and leadership of many watershed groups relies upon government
staff and funding, yet important segments of the community may inherently mistrust
government involvement. The organization and leadership of the watershed group
should be structured to ensure a community-driven prioritization and decision-making
process in the context of current rules and regulations.
Science should play an important role in providing credible information to the
watershed management process, but community representatives should ultimately
make decisions about watershed priorities and land management changes. The
organization and leadership of the watershed group should explicitly address the way in
which scientific information will be used in the decision-making process.
Many larger watershed partnerships are organized with separate policy and technical
committees, but completely separating these groups often leads to miscommunication
and other problems. Some policy representation at the technical level and technical
representation at the policy level can help to maintain good communication and ensure
an effective and efficient process.
Common characteristics of effective watershed groups include being 1) results-
oriented, 2) truth-seeking, 3) consent-based, and 4) adaptable (Pajak 2000). Results-
oriented means establishing clear, measurable objectives and regularly evaluating
results. Truth-seeking focuses on understanding watershed status and trends using
credible science. Consent-based groups are generally driven by the local community
and involve all stakeholders. Finally, adaptable means the group can work on
watershed issues at a small and large scale and use new information to adapt
management efforts.
Scoping
27
-------
Step 2. Determine watershed boundaries and key issues
The WAM methodology can be applied to any size area and at various scales, depending
on the objectives identified. Watersheds are a convenient unit of area for water-related
concerns since they typically define the area that can influence surface water. Some areas
of the United States, such as the arid Southwest or the limestone-dominated parts of
the Southeast, may not have easily defined topographic boundaries, so other assessment
boundaries may be necessary. Specific environmental issues often dictate the size and
boundaries of the watershed under consideration, but where feasible, focusing on smaller
watershed areas on the order of tens of square miles is generally most productive (Box 2).
Box 2. Hydrologic unit codes and watershed boundaries
Hydrologic unit codes (HUCs) developed by the U.S. Geological Survey (USGS) are commonly used by state and
federal agencies for defining watersheds at various scales. Most watershed data from agency reports and web sites
are organized by HUC. While HUCs may represent scales that are useful for natural resource management, they often
do not coincide with the topographic boundaries of the watershed. Where possible, the topographic boundary of the
watershed, rather than administrative boundaries, should be used to define the assessment area.
HUCs are based on a four-level classification system that divides the United States into successively smaller
hydrologic units. Each hydrologic unit is identified by a unique HUC consisting of two to eight digits based on the four
classification levels. The NRCS, together with other state and federal agencies, has further delineated fifth- and sixth-
level watersheds in many states. HUCs for these additional watershed levels consist of 11 and 14 digits, respectively,
and represent a scale of a few hundred to tens of square miles. Fifth- and sixth-level HUCs are generally a good
scale for WAM projects.
Example of HUCs from South Carolina (Bower et al. 1999)
Hydrologic
Unit Level
Hydrologic
Unit
Hydrologic
Unit Name
Hydrologic
Unit Area (mi2)
HUC
1st
2nd
3rd
4th
5th
6th
Region
Subregion
Accounting Unit
(Basin)
Cataloging Unit
(Sub-basin)
Watershed
Subwatershed
South Atlantic Gulf
Edisto-Santee
Santee
Enoree
Unnamed
Unnamed
23,600
15,300
731
82
41
03
0305
030501
03050108
03050108040
03050108040010
page
28
Scoping
-------
Most watershed groups form because of concerns about a specific watershed issue or in
response to land management or regulatory changes. The watershed group will need to
agree on the issues to be addressed as part of the WAM process (Box 3).
Box 3. Key issues for the Marshland watershed community, Snohomish County, Washington
Flood control and floodplain drainage have traditionally been the largest environmental and economic resource issues
in the Marshland watershed. A levee system along the Snohomish River protects farmland and residents from smaller
floods, but larger floods have caused significant agricultural and property damage. A network of ditches, a large canal,
and a pump plant are used to drain the area and lower the water table to take advantage of the productive floodplain
soils. Unfortunately, these projects have blocked access for salmon and drained wetlands that served as important
fish and wildlife habitat.
The Marshland watershed has also experienced significant population growth in the last 20 years. The cumulative
impacts of increased development on environmental resources, such as water quantity and quality, have not been well
addressed. The Marshland Flood Control District faces problems of tributary stream flooding, sediment deposition,
and erosion of streams and ditches as a result of both natural processes and recent development in the Marshland
uplands. The increased volume of water from residential development also increases the pumping costs for the District
to remove water from their fields. Other land management activities, such as forest removal, brush control, draining
of wetlands, erosion from fields, and fertilizer and chemical runoff have caused water quality problems and reductions
in fish and wildlife populations.
Chinook salmon and bull trout have been listed as threatened species under the Endangered Species Act. Several other
wild salmon stocks in the Snohomish River basin are also considered at risk. All of these stocks currently use habitat in
the Snohomish River valley and historically used habitat within the Marshland watershed. The Marshland floodplain area
could provide critical habitat for the restoration of salmon runs in the Snohomish River basin.
The key issues for the Marshland watershed can be summarized into the following four categories:
1. Fish access and habitat restoration to protect endangered salmon.
2. Maintenance of flood and drainage control to protect homes and agricultural lands.
3. Mitigation of urban development impacts on water runoff and erosion.
4. Improvement of water quality.
The watershed issues identified may be recorded in Form SCI (Figure 1). Table 1 provides
examples of possible watershed issues by land use.
Scoping
29
-------
Figure 1. Sample Form SC1. List of watershed issues
Watershed Issue
1. Fish can no longer be eaten
because of high levels of
pollutants
2. Bank erosion and channel
entrenchment limit land
productivity and degrade water
quality
Affected Resources
• Bass, salmon, trout
• Food and cultural resources
important to tribes
• Community recreation
• Loss of farmland
• Damage to county road
• Loss of cultural sites
• Loss of forested floodplain habitat
• Reduction in stream habitat
Possible Causes
• Pulp and paper mill effluent
• Stormwater runoff
• Naturally high mercury levels
• Larger floods due to urbanization
• Inadequate forested buffers along
streams
• Dikes and dredging
• Historical channel straightening
Table 1. Examples of possible watershed issues
Land Use
Aquatic Resources
Water Quality
Agriculture Fish migrate into drainage ditches where
dissolved oxygen levels are too low to sup-
port fry emergence.
Urbanization New development requires that a formerly
unconfined channel be taken underground.
Forestry Increased forest road development and
increased culvert placement reduce fish
passage for endangered fish.
Mining Mine tailings with arsenic and other heavy
metals contaminate important trout habitat.
Grazing Dense concentrations of cattle disturb sen-
sitive springs and amphibian habitats.
During spring rains, herbicides run
off fields into nearby creek, increas-
ing dissolved nitrogen levels.
Surface water runoff during spring
thaw deposits sediment and road
salt into nearby tributary.
Deforested watershed contributes
sediment to channel.
Heavy metals concentrations exceed
water quality criteria in streams.
Nutrient loading from animals have
increased algal blooms in slow-mov-
ing waters.
page
30
Scoping
-------
Step 3. Develop WAM goals and strategy
Once the watershed group has discussed the key issues, specific goals for the watershed
should be identified and refined. Defining watershed goals is one of the most important
parts of the WAM process. Both short- and long-term goals for the WAM process may
need to be discussed. The watershed group may start by defining broad goals for the
organization, which are often described in a "mission statement" or other "statement of
purpose." Broad goals can be useful for communication and interaction with diverse
interest groups.
More specific goals, however, are usually of greater help for guiding the actions of the
watershed group (Box 4). Consider goals that are measurable and attainable over a five-
to ten-year period. The group may also
benefit from having more project-specific
goals that are part of an annual work plan.
Box 4. Examples of broad aquatic resource goals
and considerations for refining the goals
Simply and clearly stating the goals of
the group will be an important and
effective tool for communication with the
community, as well as an important way
to measure progress. Also, keep in mind
that the determination of watershed goals
is an iterative process, and the goals will
likely be refined as more information is
gathered and stakeholders interact more
productively.
Watershed groups often underestimate the
amount of time and effort required to
accomplish watershed goals. The group
should be realistic about current and expected future resources. Small local groups
can initiate straightforward improvements through citizen outreach and watershed
stewardship programs, whereas larger-scale changes to infrastructure or regulation will
require representation by multiple agencies and community leaders (Boxes 5 and 6).
Protect drinking water sources.
- Consider surface water or groundwater.
Protect critical aquatic habitat.
- Define critical areas.
- Consider options for protection (e.g., acquisition,
easement, regulation).
Restore important aquatic habitat.
- Identify priority areas.
- Identify potential types of restoration measures.
Build public understanding and support in watershed
improvement efforts.
- Target key landowners and businesses.
- Develop educational programs with schools.
- Create a website and publish a newsletter.
Protect waterbodies to meet state water quality standards.
- Identify potential sources of impairment.
Scoping
page
31
-------
Box 5. Choosing WAM project goals
Smaller, less intensive efforts to evaluate watershed conditions can yield important insights
about watershed functions and interactions. This type of assessment can help meet a
variety of goals:
• Educating the local community about key watershed issues.
• Summarizing current information on watershed conditions.
• Identifying important gaps in knowledge.
• Organizing and prioritizing future actions.
• Conducting pilot projects for monitoring and restoration.
Involving the local community may be particularly important when conducting a WAM project
with limited resources. Staff can often be supplemented with help from local citizens and
professionals at county, state, or federal agencies.
Larger, more intensive WAM efforts can provide a more rigorous evaluation to identify
cause-and-effect relationships in watershed conditions using science-based assessments.
More detailed assessments can help meet goals such as the following:
• Educating and engaging varied interest groups in the watershed.
• Evaluating and supplementing existing watershed information.
• Identifying specific areas that require special management.
• Establishing watershed-specific standards for improved management.
• Planning cost-effective monitoring and restoration projects.
Larger assessments will require more financial and staff resources to manage the process.
Soliciting funds from various state and federal grants may be an important part of this
process.
Once the watershed goals are defined, the group should develop their strategy or "action
plan." The strategy is the process or the steps to be taken to achieve the previously
identified goals. The strategy will help define the focus of efforts in more detail and
should give guidance on prioritizing projects. A basis in science will help increase the
credibility of the strategy, but community values are an equally important consideration
in ensuring the long-term commitment necessary for effective watershed improvements.
page
32
Scoping
-------
Box 6. Project goals for the Little Miami River watershed, Clermont County, Ohio
During the development of Clermont County Project XLC, Ohio EPA and a stakeholder committee
worked with Clermont County to evaluate ten issues related to the water quality in the East Fork Little
Miami River (EFLMR) watershed. An emphasis was placed on considering nontraditional solutions, such
as seeking regulatory flexibility from state and federal authorities. The ten issues were as follows:
1. Renew and periodically review NPDES permits in the County's watershed (Milford waste water
treatment plant (WWTP), Lower East ForkWWTP, Middle East ForkWWTP, Batavia WWTP,
Williamsburg WWTP) based on new water quality findings and determinations.
2. Evaluate the feasibility of point/point trades within the EFLMR to optimize nutrient control
between facilities.
3. Consider the development of point/non-point source trading to achieve better controls of
nutrients in the watershed, possibly in coordination with Ohio EPA's EFLMR TMDL project.
4. Explore summer low flow augmentation from Lake Marsha to release higher dissolved oxygen
waters to improve biological conditions and reduce stress.
5. Review permit options to include seasonal nutrient removal limits.
6. Expedite possible innovative on-site wastewater treatment, disposal and management options
for areas of failing or discharging on-site systems.
7. Review the possibility of new discharge to the Little Miami River to accommodate treatment of
wastewater from areas with known failing on-site systems.
8. Explore potential for County ownership and management of on-site systems.
9. Evaluate riparian land controls for water quality protection.
10. Non-traditional non-point source control of water quality.
To be placed into the proper context for problem solving, each issue needed further development to
identify who needed to be involved in the process (e.g., stakeholders; specific local, state, or national
regulatory agencies), what the most appropriate methods for investigating the issue were, and whether
the County could perform the work or consultants would be needed.
The strategy is an action plan for the next 10 to 20 years that allows the watershed
group to be strategic, rather than opportunistic, in their watershed recovery efforts. The
rationale for choosing certain priorities or actions should be clearly stated within the
strategy. The following elements may be helpful in crafting a site-specific watershed
strategy:
Scoping
page
33
-------
• Geographic Priorities: Are certain sub-basins or stream reaches of particular
importance (e.g., unique, productive, critical habitat component) based on best
available knowledge?
• Community Priorities: Are recovery efforts in certain areas important to engage
community support for the entire watershed?
• Assessment: What information gaps will need to be filled in order to prioritize or
implement recovery efforts?
• Protection: Are there priority areas where current practices are ineffective in
protecting watershed resources?
• Restoration: Is the focus on protecting intact, high quality habitat or restoring
historically productive habitat?
• Monitoring: How will the group measure progress in achieving the watershed
objectives?
• Community: How will key landowners and community leaders be engaged to
participate in priority watershed protection and recovery efforts?
The strategy should be summarized in no more than a few pages so that the community
can easily understand the rationale and outcomes of implementing the strategy (Box 7).
Step 4. Consider funding and other resource needs
The financial resources available to a watershed group can vary significantly. However,
even groups with minimal resources can conduct important elements of the WAM
process and significantly improve watershed conditions. Many of the tools and
methods described in the WAM process rely on local expertise and relatively inexpensive
materials. Professionals from local government agencies, colleges, and universities are
often available to help collect and interpret information. Community outreach will be a
key component for watershed groups to recruit volunteers and other contributions.
page Scoping
34
-------
Box 7. Developing a protection and restoration strategy for the Snohomish River basin, Washington
Focus Area Concept
In the Snohomish River basin, "focus areas" support high levels of spawning, rearing, holding, or refuge for
chinook salmon. Focus areas are determined from biological data on the level of habitat use. In addition to areas
with high current use, other important areas include sites of high historical but low current use and sites with high
but inconsistent use (map).
Near-term focus areas for restoration and protection projects
Selection of Focus Areas
Local experts, including state and tribal
biologists, compiled salmon distribution data
to identify areas that support high densities
of chinook salmon. These focus areas
will become the building blocks for salmon
conservation in the watershed. Future efforts
will 1) link the focus areas to other current
and historical fish habitat, 2) link areas that
maintain the watershed processes important
to supporting high quality salmon habitat, and
3) extend this strategy to address the habitat
needs of bull trout, coho, and other salmon
species.
Habitat Condition Analysis
Habitat conditions were analyzed to help
choose the appropriate type of protection and
restoration projects. Local experts performed
the analysis with a panel of five scientists
reviewing their work and conclusions.
Project Identification
Watershed stakeholders identified specific
projects in the focus areas based on the characterization of current habitat conditions. Participants used aerial
photographs and detailed maps showing natural features, such as wetlands, and land use information, such
as dike locations and zoning boundaries. The participants also considered linkages between past and future
projects, time-sensitive opportunities and risks, and whether key watershed processes were intact.
Strategic Project List
A basin-wide workshop was held to review suggested projects for each focus area and to develop a strategic list
of project ideas. Land acquisition or conservation easements along riparian corridors are a key part of the habitat
strategy, as are more complex restoration projects, such as the removal or modification of flood control levees.
Many of these projects will require detailed feasibility studies to address issues such as public safety and the
protection of homes, businesses, farmland, and infrastructure. Restoration projects will require working with key
landowners and building community support.
(Adapted from Snohomish Basin Salmon Recovery Forum 2001)
Scoping
page
35
-------
Box 8. Federal granting agencies
The following federal agencies manage grant programs
that may help to support watershed-related work:
• U.S. Army Corps of Engineers
Section 206 Program
- Section 22 Program
• U.S. Department of Agriculture, Natural Resources
Conservation Service
Wetland Reserve Program
• U.S. Environmental Protection Agency
• U.S. Geological Survey
• U.S. Fish and Wildlife Service
• National Marine Fisheries Service
- Community-Based Restoration Program
Some watershed groups may reach a stage at
which increased funding will be necessary to
accomplish their goals. Financial grants are
commonly available from various private and
public institutions, including local, state, and
federal government agencies (Box 8). The group
should understand that the process for acquiring
and managing a financial grant might take a
large amount of effort and supplemental resources.
Project development, project management, and
administrative requirements can be significant for
many grant programs. Local government agencies
and non-profit organizations may have staff with
experience in grant writing and administration.
The time frame and resource needs for conducting the WAM process will depend on the
watershed issues, the project goals, and the scale of the assessment. The actual time and
costs associated with the WAM process will vary depending on the following factors:
• Size of the watershed.
• Availability of staff and resources.
• Amount and accessibility of existing data and information.
• Complexity of the ecological and management conditions in the watershed.
• Amount of work needed to achieve acceptable levels of confidence.
WAM outlines a framework for evaluating environmental problems and developing
effective management solutions that should increase opportunities for funding.
Involving the local community, understanding ecological processes, and using
defensible, science-based assessment are important elements for many state and federal
grants. Groups can also take advantage of in-kind support from public agencies or
citizen groups through cooperative projects, cost-share programs, or technical assistance,
rather than seeking additional grants.
The Catalog of Federal Funding Sources for Watershed Protection (U.S. Environmental
Protection Agency [EPA] 1999) lists a variety of federal monetary grants with contacts
and internet sites to obtain further information. It also provides a list of publications
and private, non-profit organizations that may provide additional sources of funding.
page
36
Scoping
-------
Step 5. Enhance community participation
The most effective watershed groups across the country actively engage and involve the
local community. Building support in the community to better address watershed issues
is vital to implement effective, long-term solutions. Cooperators such as local, state, and
federal agencies may be able to provide staff and other valuable resources to strengthen
the watershed recovery efforts. If the results of the WAM process are to influence
regulatory decisions, support applications for public funding, or have credibility in the
affected communities, full community participation is desirable.
The following potential participants may be vital to the WAM process (EPA 1997):
• Private companies and landowners whose livelihoods depend on watershed resources.
Farmers and ranchers.
Fishermen.
Timber companies.
Developers.
Fishing and hunting guides.
Utility companies.
• Offices of local, state, tribal, and federal governments.
Local watershed organizations and conservation districts.
State and county departments of environmental protection.
- NRCS.
- US DA Forest Service (USFS).
- EPA.
• Organizations that use the watershed or that are concerned with watershed or land
use issues.
Water recreation organizations.
Public health organizations.
Community economic development organizations.
Environmental groups.
Scoping
37
-------
Conducting Community Meetings to Enhance VKVM Participation
Depending on the size of the watershed and the population distribution, one or more
Scoping meetings can help inform and engage the local community (Box 9)- The
objectives of the Scoping meeting are to 1) provide an open forum for public input,
2) prioritize watershed issues, and 3) provide ideas on watershed goals. The focus of the
meeting should be to share information and generate ideas in a neutral and cooperative
atmosphere.
Box 9. Citizen involvement, Flagstaff, Arizona
The City of Flagstaff needed to update its growth management guide. The city brought together the
USFS, the State Land Department (which managed properties within the city boundaries), and the
National Park Service (which was slated to expand its boundaries). The initial issue on the table was
the interface of open space and urban areas. Through discussion, however, other issues arose, such as
the migration of elk and other large animals across highways and through residential areas, development
pressures, andfloodplain protection.
Although local, state, and federal agencies did much of the preliminary work, the group quickly
opened the process to community participation. Participation was encouraged from city and county
representatives, the Native American population, the Sierra Club, Northern Arizona University, and the
citizens of Flagstaff. As the group grew and opinions were shared, the actual goals of the group evolved,
incorporating a more complete set of concerns from the community.
Adapted from EPA (1997)
Collect background material
Maps, individually or in atlases, and other basic watershed information are readily
available from map stores, university libraries, natural resource agencies, and the
Internet. The EPA's "Surf Your Watershed" website (http://www.epa.gov/surf)
is a good place to start collecting maps and
other watershed information. The NRCS
(http://www. nrcs. usda.gov/TechRes. html) and
the USGS (http://mapping.usgs.gov) are also
good sources for maps and other landscape
information (Box 10).
Box 10. Create an information management system
Documenting the decision-making processes, storing map
data, cataloging information, and sharing information are
key components of WAM QA/QC. The following tools can be
used to facilitate information management:
GIS to store map data and generate maps.
Computer databases to store information.
Electronic mail list serve or web site to facilitate
communication.
Depending on the size of the watershed and
complexity of watershed issues, it may be helpful
to choose one person whose main responsibility is
to manage the storage and flow of information.
page
38
Scoping
-------
The following materials are helpful for most Scoping meetings and should be prepared
prior to the meeting:
Base map. A topographic or GIS map with watershed boundaries, administrative
locations (township boundaries, towns, highways, or other sites to help orient
people), and larger waterbodies (streams, lakes, wetland complexes).
Land use map. A large-scale map that generally identifies the locations of various
land uses in the watershed. Land zoning maps may be a useful source for this
information.
Land ownership map. A map that shows the general ownership pattern. A simple
map that differentiates between public and private lands may be sufficient.
Ecoregion map. A map that shows areas
with relatively uniform ecological systems
(Box 11).
Environmental maps. Other readily
available maps of vegetation communities,
wetlands, geology, soils, or precipitation
may be useful.
Watershed resources map. A map that
generally shows the location of important
community resources, such as swimming
areas, drinking water sources, and critical
fish and wildlife habitat. This map can
be refined during the Scoping meeting to
capture all important community resources.
Environmental reports. General reports
on past and present environmental
characteristics such as water quality, aquatic
habitat, water use, flooding history, climate
patterns, erosion, wetlands, or vegetation
are often available from environmental
impact statements, hydroelectric dam
licensing reports, and other watershed
assessments.
Box 11. Ecoregions
Ecoregions are defined as areas with a relatively uniform
pattern of terrestrial and aquatic ecological systems. Delineation
of ecoregions can help resource managers better understand
regional relationships of climate, topography, geology, soils, and
vegetation that influence aquatic habitats. Ecoregions can be
an effective aid for inventorying and assessing environmental
resources, setting resource management goals, and developing
biological criteria and water quality standards. Omernik and
Bailey (1997) provide a good discussion of the differences
between ecoregions, watersheds, and hydrologic units.
Two similar approaches to ecoregion mapping from the EPA
(Omernik 1995) and the USFS (Bailey 1987, 1995a, 1995b) are
readily available. For a description of the EPA's approach to
ecoregion mapping consult the website at http://www.epa.gov/
bioindicators/html/usecoregions.html. Level III and IV
mapping will be most useful for WAM. For information
on the USFS approach to ecoregion mapping, consult the
publication "Ecological Subregions of the United States"
(http://www.fs.fed.us/land/pubs/ecoregions/ecoregions.html).
Ecoregion mapping at the section or subsection scale will be most
useful for WAM. This report also has an extensive bibliography
with maps and other information on landscape characteristics
organized by region.
Scoping
page
39
-------
• Photographs. Standard and aerial photographs are often useful for illustrating various
watershed conditions or issues.
Organize meeting logistics
Depending on the scale and amount of community participation for the Scoping
meeting, the following preparations may need to be made:
• Select a convenient time and location. An evening meeting may be necessary to get
full community participation. A neutral meeting place such as a school or community
center may be preferable to government agency offices.
• Develop an agenda. A list of discussion topics and a schedule should be provided prior
to the meeting. Try to solicit speakers from various agencies and interest groups to
share information and discuss projects being conducted in the watershed.
• Prepare meeting notices and invitations. The Scoping meeting can be advertised
in local newspapers, newsletters, or other public forums. Invitations to community
groups or individuals may also be sent out along with an information packet. The
information packet could include one or more of the following items:
- A general watershed map.
- A summary of watershed issues.
- A synopsis of the WAM process.
- A meeting agenda.
- A questionnaire about community concerns.
• Promote focused discussion. It will be important to clearly define objectives for the
meeting and encourage sharing of ideas and opinions by asking questions and checking
for consensus. Consider which issues may have the greatest potential for conflict
between stakeholders. For example, conflicts often arise between rural and urban
communities, which may have different land use interests. A facilitator may be helpful
for mediating discussions and staying on schedule.
• Record ideas and minutes for meeting. Two people will often be needed to help
record ideas on a flip chart and to summarize the minutes of the meeting. For less
formal meetings, volunteers from among the Scoping participants may be used to help
record this information.
page Scoping
40
-------
The following sources provide more information on conducting such meetings:
• Leadership Skills: Developing Volunteers for Organizational Success (Morrison 1994).
• Solving Community Problems by Consensus (Carpenter 1990).
• The "Know Your Watershed" website (http://www.ctic.purdue.edu/KYW).
Conduct meeting and prioritize key watershed issues
One crucial output from the Scoping process is the discussion of key watershed issues
and how human activities may be impacting community resources. The watershed issues
should outline the perceived connections between human land uses, the response in
watershed conditions, and community resource impacts.
Visually displaying the location of community resources and areas of concern can be a
useful organizational and learning tool for meeting participants. To promote interaction
and discussion, participants can be asked to draw locations of community resources
directly onto a land use map. Alternatively, the land use and watershed resource locations
can be combined on one map or placed on clear mylar to allow for map overlays. Any
other readily available information on the watershed can also be used in a map overlay
fashion to illustrate connections between landscape and resource conditions.
If the watershed group has already identified their key watershed issues, the issues
should be shared with the larger watershed community. Community participants may
identify new issues or emphasize different aspects of issues that will require changing or
broadening the WAM goals. Be sure to create goals consistent with the commitment of
stakeholders and the availability of funding and other resources. Once the WAM goals
are finalized, record them on Form SC2.
References
Bailey, R. G. 1987- Mapping ecoregions to manage land. Pp. 82-85 in: 1987 Yearbook
of Agriculture. U.S. Department of Agriculture, Washington, D.C.
Bailey, R. G. 1995a. Ecosystem geography. Springer-Verlag, New York, New York.
Bailey, R. G. 1995b. Descriptions of the ecoregions of the United States, second edition.
U.S. Department of Agriculture Forest Service, Miscellaneous Publication No.
1391, Washington, D.C.
Scoping P_aSe
41
-------
Bower, D. E., C. Lowry, Jr., M. A. Lowery, and N. M. Hurley, Jr. 1999- Development
of a 14-digit Hydrologic Unit Code numbering system for South Carolina.
U.S. Geological Survey, Water-Resources Investigations Report 99-4015, Reston,
Virginia.
Carpenter, S. 1990. Solving community problems by consensus. Program for
Community Solving, Washington D.C.
Morrison, E. K. 1994. Leadership skills: Developing volunteers for organizational
success. Fisher Books, Tucson, Arizona.
Omernik, J. M. 1995- Ecoregions: A spatial framework for environmental management.
Pp. 49-62 in: W Davis andT. Simon (eds.). Biological assessment and criteria:
tools for water resource planning and decision making. Lewis Publishers, Boca
Raton, Florida.
Omernik, J. M., and R. G. Bailey. 1997- Distinguishing between watersheds
and ecoregions. Journal of the American Water Resources Association
33(5):935-949.
Pajak, P. 2000. Sustainability, ecosystem management, and indicators: Thinking globally
and acting locally in the 21st century. Fisheries 25(12):16-30.
Snohomish Basin Salmon Recovery Forum. 2001. Snohomish River basin chinook
salmon near term action agenda, December 2001. Snohomish County Surface
Water Management Division, Everett, Washington.
U.S. Environmental Protection Agency (EPA). 1997- Community-based environmental
protection: A resource book for protecting ecosystems and communities. EPA
230-B-96-003, Washington, D.C.
U.S. Environmental Protection Agency (EPA). 1999- Catalog of federal funding sources
for watershed protection, second edition. EPA 841-B-99-003, Office of Water
(4503F), Washington, D.C.
page Scoping
42
-------
Form SC1. List of watershed issues
Watershed Issue
Affected Resources
Possible Causes
Scoping
page
43
-------
Form SC2. WAM project goals
Project Goal
Assessment
Level
Scoping
44
-------
step 2: Watershed
Assessment
-------
Introduction
The Watershed Assessment step provides an opportunity to collect information about key
ecosystem processes that can be used to interpret watershed conditions and help guide
restoration efforts. The Watershed Assessment can be used for some of the following
purposes:
• To document current and historical watershed conditions.
• To identify important gaps in knowledge.
• To analyze the limiting factors most affecting aquatic species.
• To conduct pilot projects for monitoring and restoration.
• To establish watershed-specific standards for TMDLs.
Box 1. Technical modules
The Watershed Assessment relies on an interdisciplinary, science-based approach to
gather information about ecosystem processes, resource conditions, and historical changes.
Changes in resource conditions can be due to specific practices and events or can be
a result of the cumulative effects of management practices
throughout the watershed. Various aspects of the ecosystem
are evaluated using a series of technical modules that provide
guidance on analyzing watershed conditions (Box 1). Each
technical module contains a description of methods and tools
that can be customized to address the watershed issues and
project goals identified in Scoping.
Resource modules identify important
resources and determine resource sensitivi-
ties to changes in environmental conditions:
Community Resources
Aquatic Life
Water Quality
Historical Conditions
Process modules identify impacts caused by
land uses or management practices:
• Hydrology
• Channel
• Erosion
• Vegetation
Watershed
Assessment
page
45
-------
Watershed Assessment Process
Step Chart
Procedure
Determine the scope of the
watershed assessment
Identify the assessment team
Conduct assessment team orientation
Conduct assessment using
technical modules
Conduct pre-Synthesis
assessment team meeting
The objectives of the Watershed
Assessment step are as follows:
• To define the type of technical
analyses necessary to meet WAM
project goals.
• To conduct defensible, science-based
assessment at a watershed scale.
• To promote interaction among
scientific disciplines.
• To identify connections among
ecosystem processes, resource
conditions, and human activities.
• To effectively summarize watershed conditions, land management influences, and
information gaps.
Step 1. Determine the scope of the watershed assessment
Representatives from the watershed group who participated in the Scoping process should
review the key watershed issues and project goals with technical staff who will be working
on the Watershed Assessment. This discussion will help to ensure that the Watershed
Assessment will meet the proposed project goals (Box 2). The technical staff should discuss
the following questions with the watershed group representatives:
• Which technical modules are needed to address the key watershed issues?
• Which critical questions need to be addressed by the Watershed Assessment?
• Where are Level 1 methods sufficient to meet project goals?
46
Watershed
Assessment
-------
Where are Level 2 methods necessary to meet project goals?
How can existing studies or monitoring programs be integrated into the assessment?
Are there sufficient resources available to conduct the assessment?
What is a realistic schedule to complete the Watershed Assessment?
What issues will require long-term data collection?
Box 2. Determining the appropriate scale for the Watershed Assessment
Defining the appropriate scale at which to assess watershed conditions can
be a difficult issue. Land management practices may ultimately require site-
specific evaluations, but conducting a technical assessment at this scale
(typically a map or photo scale of 1:5,000 or smaller) is typically not feasible
or desirable for an entire watershed given time and cost constraints. A
larger scale, such as 1:50,000 or 1:100,000, may be more economical for
addressing larger watershed issues such as regional planning but may lack
the resolution necessary to recommend effective management and protection
strategies within the watershed. Working at a scale of between 1:15,000 and
1:30,000 often provides cost-effective coverage and meaningful results that can
be translated to site-specific projects. It should be emphasized, though, that
even at this scale further work will inevitably be required to address problems
at the site level. Whatever scale is used, map products should use a consistent
scale to aid comparisons and allow for map overlays.
A useful tool for outlining the watershed issues and assessment needs is the creation
of conceptual models. Figure 1 is a conceptual model illustrating components of the
ecosystem that would need to be considered to evaluate impacts of cattle grazing. Each
component of the model has an associated technical module to illustrate the potential
scope of the assessment. Within the technical modules, critical questions are provided that
can be used to further refine the scope of the assessment. Table 1 lists some common
watershed issues and the modules and associated critical questions that address each issue.
Watershed
Assessment
page
47
-------
Figure 1. Conceptual model for evaluating grazing impacts
•• Cattle Grazing (Community Resources module): Cattle grazing Is
one of many land use activities that can be culturally and
economically Important to local communities. The goal of
watershed assessment Is to ensure that these activities are
conducted In a manner that can be sustained and that does
not negatively Impact the ecosystem.
•• Physical Setting (Erosion module): Identifica-
tion of soils and parent material Is essential to
understanding erosion processes. Soils from various
bedrock materials have different erosion potentials and
support different types of vegetation.
•• Climate (Hydrology module): Consideration
must be given to weather patterns and Intensity
of rainfall as factors driving erosion processes and
affecting vegetation patterns.
•• Topography (Hydrology module): Slopes are a
^^ significant factor Influencing erosion and accessi-
bility for grazing. Slope aspect Is also Important In deter-
mining vegetation patterns.
__ Vegetation Type (Vegetation module): Information on
B™ current and historical conditions of vegetative cover can be
critical to understanding system capacity (e.g., grazing Intensity) and
changes over time due to historical uses (e.g., reduced forage). Reduced
vegetative cover or a change In species composition can lead to Increased levels
of soil erosion.
•• Riparian Zones (Vegetation and Aquatic Life modules): Riparian zones are a critical
component of the watershed, providing habitat and ecological functions (e.g., sediment buffer
strip, stream shading, and nutrient Input to streams).
ff Water Quality (Water Quality module): Water quality conditions dictate the type and status of aquatic life.
Sediment from elevated erosion levels can eliminate habitat, warm water to critical levels, and Introduce
other pollutants to the water column.
•!• Aquatic Life (Aquatic Life module): Fish are often a key ecological, cultural, and economic resource.
Aquatic species are also good Indicators of watershed ecosystem health. Impacts throughout the watershed
are reflected In aquatic habitat conditions.
•!• Stream Channel (Channel module): The stream channel Is a dynamic feature of the watershed with condi-
tions that are defined by a combination of natural physical characteristics. Changes Is sediment delivery can
modify the composition of the stream bed, and loss of streamslde vegetation can Increase bank erosion.
DELIVERED
TO STREAM
48
Watershed
Assessment
-------
Table 1. Examples of watershed issues and applicable modules and critical questions
Watershed Issues
Modules
Critical Questions*
Floods
Hydrology
Channel
Historical Conditions
H1: What is the seasonal variability in streamflow?
H7: What are the potential land use impacts to hydrologic
processes in the watershed?
C2: How do climate and the frequency, magnitude, duration,
and timing of floods affect channel conditions?
HC2: What are the natural setting and disturbance regimes in
the watershed?
Drinking water
Water Quality
Hydrology
Community Resources
WQ2: What water quality parameters do not meet the standard
and for what time period?
H6: For which beneficial uses is water primarily used in the
watershed, and are surface water or groundwater withdrawals
prominent?
CR4: What processes or land use activities may be impacting
community resources?
Floodplain/riparian
conditions
Vegetation
Community Resources
Aquatic Life
Hydrology
Channel
V4: Does existing upland, riparian, or wetland vegetation differ
substantially from historical conditions?
V6: What are the important functions of riparian vegetation
relative to watershed processes?
CR2: Where are community resources located?
AL3: What are the requirements of various life history stages of
the aquatic species?
H5: What water control structures are present in the watershed?
C5: How and where have changes in riparian vegetation
influenced channel conditions?
Algae blooms/
eutrophication
Water Quality
Aquatic Life
WQ7: What causes excessive algae growth or eutrophication?
AL5: What connections can be made between past and present
human activities and current habitat conditions?
Water temperature
Water Quality
Aquatic Life
Vegetation
WQ2: What water quality parameters do not meet the standard
and for what time period?
AL3: What are the requirements of various life history stages of
the aquatic species?
V6: What are the important functions of riparian vegetation
relative to watershed processes?
Loss of rare native
plant
Community Resources
Vegetation
CR2: Where are community resources located?
CR4: What processes or land use activities may be impacting
community resources?
V1: What are the primary vegetation categories that exist in
upland areas?
V4: Does existing upland, riparian, or wetland vegetation differ
substantially from historical conditions?
H1 = Module and critical question number
Modules: AL = Aquatic Life
C = Channel
CR = Community Resources
E = Erosion
H = Hydrology
HC = Historical Conditions
V = Vegetation
WQ = Water Quality
Watershed
Assessment
page
49
-------
Table 1. (continued)
Watershed Issues
Modules
Critical Questions*
Wetlands functions
and values
Hydrology
Vegetation
Aquatic Life
Community Resources
H3: What are the roles of groundwater and natural storage
features in the watershed?
V3: What are the primary vegetation categories that exist in
wetland areas?
V7: What are important functions of wetland vegetation
relative to watershed processes?
A3: What are the requirements of various life history stages of
the aquatic species?
CR2: Where are community resources located?
Bank erosion
Erosion
Hydrology
Vegetation
Channel
Water Quality
E10: How significant a sediment source is streambank
erosion, and how have erosion rates changed over time?
H1: What is the seasonal variability in streamflow?
V6: What are the important functions of riparian vegetation
relative to watershed processes?
C1: How does the physical setting of the watershed influence
channel morphology?
C3: How and where has the behavior of the channel changed
over time?
WQ9: What conditions lead to excessive turbidity?
Fish consumption
advisories
Aquatic Life
Water Quality
A2: What are the distribution, relative abundance, population
status, and population trends of the aquatic species?
WQ5: What causes fish consumption advisories?
Dams
Hydrology
Channel
Aquatic Life
Historical Conditions
H5: What water control structures are present in the watershed?
C10: How does the presence and management of dams and
levees affect channel conditions?
A5: What connections can be made between past and present
human activities and current habitat conditions?
HC3: Where and when have landscape changes occurred in
the watershed?
Threatened or
endangered aquatic
species
Aquatic Life
Channel
Erosion
Vegetation
Hydrology
A5: What connections can be made between past and present
human activities and current habitat conditions?
A2: What are the distribution, relative abundance, population
status, and population trends of the aquatic species?
C11: What is the potential for change in channel conditions
based on geomorphic characteristics?
E12: What are the primary sources of sediment delivery to
waterbodies?
V6: What are the important functions of riparian vegetation
relative to watershed processes?
H6: For which beneficial uses is water primarily used in the
watershed, and are surface water or groundwater withdrawals
prominent?
H1 = Module and critical question number
Modules: A = Aquatic Life
C = Channel
CR = Community Resources
E = Erosion
H = Hydrology
HC = Historical Conditions
V = Vegetation
WQ = Water Quality
50
Watershed
Assessment
-------
Technical advisors may want to discuss hypotheses about watershed processes and
resource impacts (Box 3)- These hypotheses may also help further refine the scope and
level of assessment necessary to meet project goals. Hypotheses related to issues identified
in Figure 1 might include the following:
• Grazing on highly erodible soil contributes the majority of sediment to streams.
• Natural soil erosion causes high turbidity measurements.
• Grazing has altered vegetation communities and increased stream temperatures.
• Erosion from grazing is only a problem on steep slopes near streams.
• Floods are responsible for increased bank erosion.
• Grazing has significantly increased bank erosion and altered aquatic habitat.
If significant changes are proposed in the scope of the Watershed Assessment, it may be
necessary to review the issues with all Scoping participants.
Box 3. Generating hypotheses
Generating hypotheses is a vital part of any scientific assessment. Hypotheses can help to determine
the required scope of assessment and to focus data collection and analysis on specific objectives. A
hypothesis is defined as an assumption that needs verification or proof. Hypotheses are clearly defined
statements that can be evaluated during the Watershed Assessment. Data from the assessment can
then be used to support or disprove the hypotheses. Often, further data collection and evaluation of
competing hypotheses are necessary following the initial Watershed Assessment.
Using a hypothesis to guide the Watershed Assessment
Hypothesis:
Grazing has increased the amount of fine sediment on the streambed due to
soil compaction and trampling of the streambank.
Level 1 Assessment: The Erosion module identifies soil types that are most susceptible to
disturbance from grazing. The Channel module maps bank disturbance from
aerial photos. The Aquatic Life module analyzes stream survey data on the
percentage of fine sediment in streams.
Level 2 Assessment: The Erosion module quantifies erosion from different land management
practices on various soil types. The Channel module quantifies bank erosion
using field surveys and predicts sediment transport capacity of streams. The
Aquatic Life module identifies potential fish spawning sites and measures fine
sediment in the streambed.
Watershed
Assessment
page
51
-------
Step 2. Identify the assessment team
Table 2. Types of specialists to consult for a Level 2 assessment
Module
Profession
Community Resources
Aquatic Life
Water Quality
Historical Conditions
Hydrology
Channel
Erosion
Vegetation
The assessment team comprises environmental professionals who will use the technical
modules or other methods to assess the watershed. For smaller assessments,
the team may be composed
of just a few local natural
resource professionals, but for
more complex issues, such as
those addressed in a Level 2
assessment, many trained
specialists and staff may be
necessary (Table 2).
Historian, Anthropologist, or Archaeologist
Aquatic or Wildlife Biologist
Aquatic Ecologist, Environmental Engineer,
Aquatic Biologist, Water Chemist, or Hydrologist
Historian or Librarian
Hydrologist or Environmental Engineer
Geomorphologist, Hydrologist, or Geologist
Geologist, Geotechnical Specialist, Soil Scientist,
or Geomorphologist
Ecologist or Botanist
Step 3. Conduct assessment team orientation
The composition of the assessment team will depend on the scope of the Watershed
Assessment. A team leader is always important to coordinate logistics and to manage
the assessment team. The team leader should make sure that assessment team members
are acquainted with the watershed (e.g., by distributing maps and environmental
reports) and with the WAM process (e.g., by providing copies of the WAM guide or a
technical module). The team leader will also be responsible for producing a Watershed
Assessment report. Table 3 provides a list of materials that are typically necessary for
a Level 1 assessment.
The team leader should organize an initial meeting of the assessment team to do the
following:
• Introduce team members.
• Distribute a team contact list.
• Clarify assessment objectives and hypotheses.
52
Watershed
Assessment
-------
Table 3. Typical Level 1 assessment information needs
USGS topographic maps
Watershed base map
Land use map
Ecoregion summary
Geology maps
Soils map
Slope class map (if GIS available)
Aerial photos
Orthophotos
Fish habitat surveys
Channel modification information
Mean annual precipitation data
USGS stream gage data
Existing vegetation maps
National Wetland Inventory (NWI) maps
Federal Emergency Management
Agency (FEMA) floodplain map
Water quality data and reports
305 (b) list of state waterbodies
303 (d) list of state waterbodies
Endangered Species Act (ESA) listings
or state endangered species
National Pollutant Discharge
Elimination System (NPDES)
permit compliance data
Community
Resources
•
•
•
Aquatic
Life
•
•
•
•
•
•
•
•
•
Water
Quality
•
•
•
•
•
•
•
•
•
•
•
•
Historical
Conditions
•
•
•
•
•
•
Hydrology
•
•
•
•
•
•
•
•
•
•
•
•
Channel
•
•
•
•
•
•
•
•
•
•
Erosion
•
•
•
•
•
•
•
•
Vegetation
•
•
•
•
•
•
•
•
•
•
Identify sources and availability of watershed data, aerial photos, maps, and
environmental reports.
Assign responsibilities for data collection and analysis (Box 4).
Discuss assessment product requirements such as maps and reports.
Establish assessment schedule.
Note travel issues, such as gate keys, permission for access, and safety.
Conduct a field tour of the watershed.
Watershed
Assessment
page
53
-------
Box 4. Emphasizing an interdisciplinary approach
Many of the tasks conducted by individual analysts during the
Watershed Assessment will generate useful information for other
people on the assessment team. Sharing this information during
the assessment will improve each module's evaluation and prepare
the team for a productive Synthesis session. Within each technical
module, arrow icons like the one shown below identify opportunities
for sharing information with other module analysts. Data, prelimi-
nary conclusions, and other ideas can be shared using email, infor-
mation-sharing software, fax, or telephone.
During the team orientation, it will be help-
ful to delineate sub-basins together so that
areas of special interest can be analyzed at
a similar scale. The assessment team
should also discuss opportunities for joint
data collection (e.g., stream surveys to col-
lect data for the Water Quality, Aquatic Life,
Channel, and Hydrology modules).
Hydrology
Vegetation
Water Quality
Step 4. Conduct assessment using technical modules
Each module analyst should review the appropriate technical module and customize
the methodology as necessary to address the specific watershed issues and project goals
identified during Scoping. The technical modules are located in the final sections of
this guide.
The assessment team leader should periodically monitor the progress of the Watershed
Assessment. The team leader may need to ensure that information sources are
being shared and dialogue and interaction are occurring among team members. If
GIS is being relied upon for analyses or map production, the team leader should
coordinate regularly with the GIS specialist(s) to ensure a smooth and efficient transfer
of information.
54
Watershed
Assessment
-------
Step 5. Conduct pre-Synthesis assessment team meeting
A meeting of the assessment team prior to beginning the more formal Synthesis process is
usually helpful to accomplish the following:
• Discuss interim findings and conclusions.
• Refine hypotheses based on shared information.
• Identify further assessment work needed.
• Review schedule and objectives.
Technical module analysts should be prepared with preliminary maps, tables, and graphs
to summarize their findings. Preparing this material prior to Synthesis helps to organize
the assessment results and identify gaps in information. Most of the material can also be
used during Synthesis and in the Watershed Assessment report.
Watershed
Assessment 55
-------
56
Watershed
Assessment
-------
Step 3: Synthesis
-------
Introduction
The Synthesis step of the WAM process provides an opportunity for interaction
among the assessment team members to provide a more comprehensive picture of
the watershed. Synthesis is generally an interdisciplinary evaluation involving a larger
assessment team, but even smaller assessment teams can summarize and evaluate the
information in an interdisciplinary fashion. These discussions often lead to new insights
about important watershed processes and the status of community resources.
Synthesis Process
Step Chart
Procedure
The objectives of the Synthesis step are
as follows:
• To share information generated from
various areas of the assessment.
• To identify important interactions
among land uses, watershed
processes, and community resources.
• To summarize key watershed issues
to be addressed in the Management
Solutions step.
• To determine potential future actions
for key watershed issues (e.g., Level 2
assessment, management practices,
restoration plans, monitoring plans).
Prepare for the Synthesis process
Present Watershed Assessment results
Identify connections between land use practices
and resource impairment
Summarize watershed issues
Produce Watershed Assessment report
Synthesis
57
-------
Step 1. Prepare for the Synthesis process
The Synthesis process is typically organized and facilitated by the assessment team
leader. The assessment team members are the primary participants, but other
community members may also be interested in following the process. The team leader
will need to notify potential participants and schedule Synthesis meetings. Synthesis
meetings may last from two days to a few weeks, depending on the complexity of
watershed issues and the scope of the assessment. If more than two to three days will
be required to complete the Synthesis process, it is advisable to spread out the meetings
over two to three weeks. A break between Synthesis sessions is important not only to
maintain the focus of the participants but also to allow for follow-up work to address
questions raised during Synthesis or to fine-tune the assessment.
At the Synthesis meetings, the assessment team members should be prepared to present
the results of their respective assessments along with appropriate maps. The checklist
provided in Box 1 summarizes the important products from each WAM technical
module. Depending on the scope of the assessment, some of these products may not
have been created. Ideally, the analysts would have a draft of their module reports
completed. Writing draft reports prior to Synthesis ensures that critical work has been
completed and helps identify information needs and potential linkages with other
modules. Completion of maps and forms will help make the Synthesis meetings
effective and efficient.
A number of general Synthesis questions that may need to be addressed by each module
are presented in Box 2. These questions illustrate the types of issues addressed by the
Synthesis process and may not be appropriate for all watershed assessments.
Step 2. Present Watershed Assessment results
If some Synthesis participants are unfamiliar with the WAM process, the team leader
should orient participants on the purpose of the Watershed Assessment, the issues
identified in Scoping that were investigated by the assessment team, and the role of
Synthesis meetings in the WAM process.
Synthesis
58
-------
Box 1. A checklist of module products needed for Synthesis
Module
Products
Community Resources
Aquatic Life
Water Quality
Historical Conditions
Hydrology
Channel
Erosion
Vegetation
EH Map CR1. Community resources
EH Form CR1. Categorization of community resources
EH Form CR2. Trends in community resource conditions
EH Map AL1. Aquatic species distribution
EH Map AL2. Aquatic habitat distribution
EH Map AL3. Aquatic habitat conditions
EH Form AL1. Summary of hypotheses
EH Map WQ1 .Water quality impairments
EH Form WQ1. Summary of water quality conditions
EH Map HC1. Historical sites
EH Form HC1. Historical timeline
EH Form HC2. Trends in watershed resource conditions
EH Map H1. Water control structures
EH Form H1. General watershed characteristics
OH Form H2. Summary of hydrologic issues by sub-basin
EH Map C1. Channel segments
I I Map C2. Geomorphic channel types
I I Form C1. Historical channel changes
EH Form C2. Geomorphic channel type characteristics
EH Map E1. Land types
EH Form E1. Summary of erosion observations
EH Form E2. Summary of land type characteristics
EH Map V1. Upland vegetation
EH MapV2. Riparian/wetland vegetation
EH Map V3. Land use practices that affect vegetation
EH Form V1. Vegetation category summary
Syntht
59
-------
Box 2. Synthesis questions
Community Resources
• What are the ecological needs of community resources relative to hydrology, erosion, stream conditions,
vegetation, and water quality?
Aquatic Life
• What are the habitat requirements of aquatic life in the watershed?
• How is aquatic life affected by interactions among erosion, hydrology, riparian function, water quality,
and stream channel processes?
• How is the distribution of aquatic species influenced by natural conditions?
Water Quality
• How have resources in the watershed been affected by pollutants?
• How do natural conditions in the watershed influence water quality in various waterbodies?
• How do natural conditions in the watershed influence the transport and fate of pollutants in the
watershed?
• How have land use practices influenced water quality conditions in the watershed?
Historical Conditions
• When have land use/management changes altered watershed conditions?
Hydrology
• How do climate, geology, and topography influence surface and sub-surface water flow through the
watershed?
• How has land use altered the flow of water through the watershed?
• How have alterations in the flow of water influenced conditions for resources?
Channel
• How do watershed climate, geology, and topography influence runoff, sediment transport, and aquatic
habitat conditions?
• How do channel conditions influence physical and biological processes in the streams?
Erosion
• How do the climate, geology, and topography of the natural landscape influence sediment generation
and transport in the watershed?
• How do land use activities change the frequency and magnitude of erosion at a watershed scale?
• How have alterations in the flow of water influenced conditions for resources?
Vegetation
• How have vegetation communities changed over time, and what has caused these changes?
• What riparian and wetland functions are important for protecting aquatic habitat, water quality, or other
community resources?
page
60
Synthesis
-------
The first day of Synthesis meetings
. Box 3. Assessment team presentations
is typically devoted to presentations or
information gathered by the assessment ,- , , . . . , . , . ., , .. . . ,
b } Each module analyst should present the following information:
team. Presentations should be tailored
• Module objectives and critical questions.
to the knowledge and experience of
A brief description of materials and methods.
A summary of results using maps, figures, and tables.
A discussion of the findings and the relationship to other modules.
the participants in the Synthesis meeting
(Box 3). After each presentation,
additional time will typically be required
to discuss the findings and consider
information from other module analysts. The total time for each module presentation
and discussion should be no more than one hour so that all the presentations can be
completed in a day.
Step 3. Identify connections between land use practices and resource
impairment
After the first day of assessment team presentations, the Synthesis meetings should
focus on outlining the linkages between modules and summarizing watershed issues.
Depending on the complexity of watershed issues, the amount of available information,
and the size of the watershed, this step may require from one to several days to complete.
Outlining potential connections among land use practices, watershed processes, and
community resources can be approached from a number of angles. In a Level 1
assessment, starting with a resource is typically a good way to begin developing potential
explanations or hypotheses for impairment (Box 4). Information from various modules
can provide insight on the potential for delivery of hazardous inputs or the influence
of natural conditions on the state of the resource. The Synthesis group should work
together in developing various hypotheses and identifying the most promising hypotheses
as watershed issues.
Hypotheses should be scrutinized based on the following:
• An evaluation of plausible alternatives.
• Existence of supporting scientific data.
• Different lines of supporting evidence.
• The ability of factors to amplify or attenuate an effect.
Synthesis
61
-------
Box 4. Identifying connections between an impaired resource and land use
practices, an example from the Penobscot River basin, Maine
Step 1. Identify Impaired Beneficial Resource
One of the critical issues in the Penobscot River basin, Maine, is a fish
consumption advisory due to contamination with mercury, dioxin, and
PCBs. Fish are an important cultural resource for the Penobscot Indian
Nation, and angling is an important recreational activity for the entire
watershed community.
Step 2. Identify Potential Sources of Impairment
Potential sources of these pollutants include discharge of wastewater
from paper mills, contaminated sediments in the Penobscot River, aero-
sol deposition from industrial smokestacks, and naturally occurring mer-
cury-bearing rocks.
Step 3. Identify Relevant Watershed Processes and Data Needs
Water chemistry data are important for identifying potential point source
discharges. Stream sediment composition, pollutant load, and transport
characteristics are important data to determine the significance of this
source of pollutants. Geology information may also be crucial for identi-
fying potential natural sources of mercury. Since fluctuating water levels
allow mercury to be methylated and thus susceptible to uptake by bio-
logical organisms, information on changes in streamflow and dam opera-
tions may also be important.
Step 4. Identify Promising Hypotheses and Information Gaps
Point source discharges of pollutants from wastewater and smokestacks
are the most likely sources of impairment. Little information exists on
contaminated sediments and the potential for biological uptake, but this
is potentially an important source. A review of geologic data revealed
that rocks in the area contain minimal amounts of mercury.
Evaluating hypotheses will help
to identify gaps in knowledge,
increase confidence in cause-and-
effect relationships, and prioritize
future actions.
The Synthesis group may find that
in some cases it is easier to develop
hypotheses around a landscape
sensitivity or land management
practice. Landscape sensitivities
might include a landform that is
particularly susceptible to erosion
or a vegetation community that is
easily disturbed. Land management
practices that are consistently
causing problems can also be the
focus of a hypothesis. For example,
forest road construction within 100
feet of streams may consistently
cause sedimentation problems, or
stormwater discharge into shallow
lakes may cause an increase in algae
bloom size and duration.
Step 4. Summarize watershed issues
Watershed issues can be categorized in three general ways: 1) by community resource,
2) by hazardous input (e.g., pollutant), or 3) by land use practice (Box 5). Categorizing
watershed issues is a subjective process, but it is important to provide detailed
information on the issues in a form that the Scoping participants and the management
team can understand and use to make decisions. The following details should be
provided for each issue:
page
62
Synthesis
-------
Box 5. Organizing watershed issues, example
from the Penobscot River basin, Maine
The Penobscot River basin has a number of
beneficial resources impacted by point source
discharge of pollutants such as RGBs, dioxin,
and mercury (Box 4). The issue of mercury
loading is sufficiently complex and different from
the other pollutant issues to merit consideration
on its own. While impairment of resources was
the focus of initial discussions, the watershed
issues in this case were more logically organ-
ized according to the hazardous inputs:
1) PCBs and dioxin, and 2) mercury.
• The management activities potentially causing
impairment.
• The location of hazardous inputs.
• The location of sensitive resources.
• The mechanism of impairment.
• Data and other evidence to support conclusions.
At this point, it will be helpful to review the issues
identified during Scoping in light of the Watershed
Assessment and the discussion of hypotheses. Based
on this discussion, general watershed issues identified
during Scoping may need modification to better reflect
current knowledge or to highlight specific concerns. New
watershed issues may also be identified.
Form SI provides a template for summarizing important watershed issues (Box 6,
Figure 1). Form SI is one of the primary products of the Synthesis process and will
be a key element of the last two WAM steps: Management Solutions and Adaptive
Management. The following paragraphs describe each element of Form SI in further
detail.
Box 6. Information to include in Form S1. Summary of watershed issues
Watershed Issue: The
community resource,
hazardous input, or land
use practice that is the
focus of the issue should
be clearly identified.
Watershed Issue:
Location:
Situation Summary:
Recommendations:
Justification:
Community Resource, Hazardous Input, or Land Use
Practice
Sub-basin, Stream Segment, Waterbody, or Landform
(reference maps and figures as necessary)
Input from Watershed, Time Frame, Watershed Proc-
ess, Hazard Location, Management Activity, Delivery
Conditions, Sensitive Resource Location, Channel
and Resource Effects
Level 2 Assessment, Management Changes, Restora-
tion Plan, or Monitoring Plan
Supporting Data, Criteria for Resource Sensitivity,
Delivery Potential, Confidence in Assessment
Location: The area
affected by the particular
watershed issue should be
referenced as specifically
as possible. The location
may be as large as the
entire watershed or a sub-
basin or as specific as one stream segment or landform. Reference appropriate maps to
help people who are unfamiliar with the watershed or who did not participate in the
assessment.
Synthesis
63
-------
Figure 1. Sample Form S1. Summary of watershed issues
Watershed Issue: Soil Erosion
Location: Erosion Units 1 and 2 (Map E1) in the Bear Creek and Crazy Creek sub-basins.
Situation Summary:
Soil erosion is a problem in Erosion Units 1 and 2 due to disturbance of erodible soils from
1) road construction, 2) rerouting of water drainage from paved surfaces, 3) compaction of
soil from grazing, and 4) natural erosional processes (weathering, soil creep, dry ravel,
bank erosion). Sediment delivery to streams generally occurs within 75 feet of waterbodies.
Most of the problems occur in low-gradient, moderately-incised streams in loess deposits
(Channel Type 8). The accumulation of fine particles affects fish and aquatic plants by
1) reducing egg to fry survival for fish by cementing gravel and reducing the flow of oxygen,
and 2) preventing the growth of snake reeds, which are an important tribal resource for
basket-weaving and traditional medicine.
Recommendations:
1. Work with rural residential and forest landowners to develop options for reducing
sediment delivery from gravel roads.
2. Work with the County Land Development and Engineering department to improve
current and future water drainage structures and storm runoff detention.
3. Develop grazing management plan to reduce streambank trampling and to revegetate
riparian corridors.
4. Conduct a Level 2 assessment to better quantify the sources of erosion.
5. Monitor the percentage of fine sediment before and after implementation of BMPs.
Justification:
Field observations, anecdotal information, and stream surveys provide evidence for the
erosion problems in these two land types. Gant et al. (1999) and unpublished tribal and
county reports provide more detailed examples of problems. While a high level of fine
particles probably existed naturally in streams running through these loess deposits, land
management practices have visibly increased their volume. A level of 30% fines or higher
was considered a problem based on habitat requirements for fish. A high level of
confidence exists in identifying the causes for erosion because of its broad documentation.
A Level 2 assessment, however, would help to quantify each source of erosion and thus
help in prioritizing and justifying management solutions.
page
64
Synthesis
-------
Situation Summary: The
situation summary describes
the watershed problem in a
simple and structured fashion
(Box 7). The basic elements
of the situation summary are
provided in Box 6 and are
illustrated in Box 8.
Box 7. Developing situation summaries
Development of situation summaries can be a time-consuming process
that requires focused writing and editing. While these summaries rely on
information from several different modules, it may be desirable to have
one individual or group of individuals produce initial drafts of the situation
summaries outside of the Synthesis meetings. Rather than spending the
entire group's time describing each watershed issue in detail, the Synthesis
meetings can then be more effectively used to critique and modify the draft
situation summaries.
Box 8. Sample situation summary
Input from Watershed
Time Frame
Watershed Process
Hazard Location
Management Activity
Delivery Conditions
Channel Effects
Sensitive Resource Location
Resource Effects
Fine sediment
from past and potential future
soil erosion in
Erosion Units 1 and 2
due to 1 ) disturbance of erodible soils from road construction,
2) rerouting of water drainage from paved surfaces, 3) com-
paction of soil from cattle grazing, and 4) natural erosional
processes (weathering, soil creep, dry ravel, bank erosion)
within 75 feet of streams and wetlands
has caused and/or could cause accumulation of fine particles
within low-gradient, moderately-incised channel types in loess
deposits (Channel Type 8)
that can 1 ) reduce egg to fry survival for fish by cementing
gravel and reducing the flow of oxygen and 2) prevent the
growth of snake reeds, which are an important tribal resource
for basket-weaving and traditional medicine.
Recommendations: The quality of data available for
the Watershed Assessment, the assessment scale or
level of detail, and the confidence in conclusions
drawn from the assessment will all influence potential
recommendations (Box 9)- The intent of making
recommendations is to provide guidance for future steps
rather than to develop specific management solutions.
Management solution development will occur in the
next step of the WAM process.
Box 9. Confidence in recommendations
Lack of quality data or confidence in the
assessment results should lead to further
study in the form of a Level 2 assessment or
longer-term monitoring. Strong evidence for
cause-and-effect relationships is required to
recommend management changes or resto-
ration plans.
Synthesis
65
-------
Box 10. Confidence summaries
Justification: Providing evidence for conclusions from the Watershed Assessment is
one of the most important exercises in the Synthesis process. Sources of data or
other evidence should be referenced to support
the situation summary. The standards or
criteria used to rate landscape hazards, resource
sensitivities, and delivery potentials should be
clearly described. Finally, confidence in the
assessment and conclusions should be discussed.
A High/Moderate/Low rating can be used to
assess confidence, but the summary should also
provide explanations for each rating (Box 10).
Rating confidence in the assessment and
conclusions should be based on the following:
• The availability of information.
• The quality of information.
• The ability to analyze and interpret the data
• The lack of alternative explanations.
Step 5. Produce Watershed Assessment report
The assessment team leader is typically responsible for producing an overall Watershed
Assessment report. The format for this report is flexible, but the report should
provide easily accessible information to community members. In most cases, a concise
report will be more effective in communicating watershed issues than will a complex
technical document with extensive data. Striking a balance between the need to
communicate effectively with a potentially diverse audience and the need to provide
scientific documentation to support conclusions is one of the greatest challenges in
creating a useful Watershed Assessment report.
While each module analyst should have a short report on assessment results, the team
leader must synthesize this information to provide a comprehensive picture of watershed
conditions. This comprehensive picture can be effectively presented as the watershed
story, a narrative that describes historical conditions and evaluates the effects of changes
over time. The format of the Watershed Assessment report is flexible, but the report
should describe important results and conclusions in a succinct manner (Box 11). The
maps, tables, and forms produced in each module are designed to provide concise
summaries of results as well as logic tracking for quality assurance and control.
page
66
Synthesis
-------
Box 11. Example outline for a Watershed Assessment
report
IV.
Introduction
A. Purpose/objective of assessment
B. List of sponsors and participants
C. Watershed issues
D. Regulatory or policy issues
Description of Watershed
A. Location, size, ownership, and land uses
B. Topography, geology, soils
C. Climate
D. Streams, sub-basins, waterbodies
E. Vegetation
F. Historical land uses and disturbances
Summary of Watershed Assessment
A. Watershed story
B. Summary of issues
C. Recommendations
D. Research and monitoring needs
E. Confidence in assessment
F. Quality assurance and control
Technical Module Reports
A. Community Resources
B. Aquatic Life
C. Water Quality
D. Historical Conditions
E. Hydrology
F Channel
G. Erosion
H. Vegetation
Synthesis
67
-------
Form S1. Summary of watershed issues
Watershed Issue:
Location:
Situation Summary:
Recommendations:
Justification:
page
68
Synthesis
-------
step 4: Management
Solutions
-------
Introduction
The goal of the Management Solutions step is to create a watershed management plan to
address the issues identified during Scoping, Watershed Assessment, and Synthesis. The
management plan should describe multiple management solutions to provide flexibility in
the implementation of watershed improvements (Box 1).
Management solutions for addressing watershed issues
or problems can take many forms:
• Changes in land use (e.g., land use planning or
zoning).
• Changes in management practices (e.g., Best
Management Practices [BMPs]).
• Monitoring programs.
• Educational programs.
• Restoration plans.
• Regulatory changes (e.g., water quality standards
and criteria).
The type of management solutions developed through
the WAM process will depend largely on the scale and
level of assessment. A Level 1 assessment provides a
general characterization of the watershed that may be
useful for land use planning, identifying monitoring
needs, or developing educational programs. This
level of information is typically not detailed
enough to evaluate or suggest specific prescriptive
actions. A Level 2 assessment can provide more
site-specific information that can be used to evaluate
the effectiveness of management practices, identify
restoration opportunities, or establish resource-based
water quality standards.
Box 1. Watershed management planning
in Nantucket, Massachusetts
In response to a variety of threats to Nan-
tucket's water supply, the Nantucket Land
Council, a private, non-profit organization,
commissioned the development of a water
resource management plan. Twelve water
resource protection areas were delineated as
part of the plan and designated for priority
protection. Among these areas were well-
head protection areas for the island's two
principal public water supply wells, a larger
aquifer protection area designated as a
source of future water supplies, and the
drainage areas for coastal and freshwater
ponds. The designated areas were protected
by a combination of regulatory and non-regu-
latory measures, including zoning districts
that regulated land use, subdivision and wet-
lands regulations, on-going water quality
monitoring, and public education campaigns
discussing the residential use of lawn fertil-
izer and household chemicals.
Adapted from EPA (1995a)
Using information generated during the previous steps, the WAM approach can provide
a strong link between community values, scientific information, and the development of
Management
Solutions
page
69
-------
practical and effective management solutions. Information from these steps is used to
identify resource needs, the effects of current and past management, and the success or
failure of past practices. With broad community participation and support, the technical
information can be used to suggest effective management changes to protect and enhance
the valued resources identified during the Scoping process.
Watershed management plans should be integrated with existing programs and tailored
to the needs of the community and the unique character of the watershed. Ideally,
multiple programs and solutions will be developed as part of the management plan to
provide flexibility in the implementation of watershed improvements. Existing projects
and programs such as water quality monitoring or stream restoration should be considered
elements of a comprehensive watershed approach to management solutions.
This section describes the steps to develop a watershed management plan. Examples of
management objectives and solutions are provided. Information on watershed restoration
is described, and possible sources of funding are identified. Information on developing
monitoring programs can be found in the next section, Adaptive Management.
Management Solutions Process
Step Chart
Procedure
The objectives of the Management
Solutions step are as follows:
• To use information from previous steps
to develop management objectives and
options.
• To create a watershed management
plan.
• To develop incentives for
implementation of management
solutions.
Assemble management team
Evaluate Watershed Assessment
and Synthesis products
Develop management
solutions
Create watershed
management plan
page
70
Solutions
-------
Step 1. Assemble management team
The management team will be responsible for setting management objectives and
developing a set of prioritized options for each objective. Deciding who will participate
on the management team depends upon the number of people involved in the WAM
process. If a small number of people are involved, it may be possible to include all
participants in the management team. Otherwise, a cross-section of community leaders
and technical staff should be included on the management team. If effective changes are
expected from this process, it is vital to include representatives from all interested parties
who might be affected by the proposed management changes.
A combination of people with technical and policy backgrounds in environmental
resource management is ideal to identify and evaluate options for changes in
management practices and watershed programs. At least a few individuals who
participated in the Watershed Assessment can be a part of the management team to
provide background information and help resolve technical questions. Land owners,
industry representatives, and regulatory agencies may also be integral for developing
effective management solutions.
Step 2. Evaluate Watershed Assessment and Synthesis products
Before management objectives and solutions can be written, it is important to
understand the results of the Watershed Assessment and the summaries of watershed
issues that were produced in Synthesis (Form SI). The summaries of watershed issues
may provide sufficient detail for establishing objectives and solutions, but often a more
comprehensive understanding of watershed issues is necessary. If the management
team is identified ahead of time, it may be helpful for members to attend the
Synthesis meetings. Another option is for the assessment team to provide a summary
presentation to the management team. A field review of the watershed or specific areas
of concern may also be warranted to provide further information for developing effective
management solutions.
Step 3. Develop management solutions
The summaries of watershed issues (Form SI) from Synthesis provide a list of watershed
concerns that may require specific management solutions. The team should develop a
management objective for each issue. A set of specific solutions can then be written
Management page
Solutions 71
-------
to address each objective. Multiple options are encouraged for each objective to provide
flexibility for implementation by community members (Box 2). The objectives and
solutions should be recorded on Form Ml (Figure 1). The rationale for each solution
should also be recorded for future reference. Rationale may be based on local data,
technical and management expertise, or scientific literature.
Box 2. Management planning in the Klamath River basin, Oregon
Physical obstructions, habitat destruction, and pollutants have severely degraded an
important tribal and commercial salmon and trout fishery in the Klamath River, Oregon. The
long-range restoration plan was developed using a sequence of goals, objectives, policies,
and priority projects. Examples of goals, objectives, and policies from this program are
provided below.
Goal: Restore by 2006 the biological productivity of the basin in order to provide
for viable commercial and recreational ocean fisheries and in-river tribal and
recreational fisheries.
Objective: Protect stream and riparian habitat from potential damage caused by timber
harvesting and related activities.
Policies: • Improve timber harvest practices through local workshops; develop habitat
protection and management standards for agency endorsement; and create a
fish habitat database.
• Evaluate current timber harvest practices by developing an index of habitat
integrity; incorporating fish habitat and population data into state water quality
assessments; and monitoring recovery of habitat in logged watersheds.
• Promote necessary changes in regulations, including state forest practice rules,
USFS policies in land management plans, and BMPs.
• Anticipate potential problems by requesting additional state monitoring
programs; modifying state and federal rules to protect erodible soils; and giving
priority to protection of unimpaired salmon habitat.
Adapted from Klamath River Basin Fisheries Task Force (1991)
page
72
Solutions
-------
Figure 1. Sample Form M1. Summary of management options
Issue
Erosion from gravel
roads
Untreated
wastewater delivery
to the Massassaqua
River
Protection of unique
natural areas for rec-
reation and wildlife
habitat
Pollutants in drinking
water
Management Objective
Minimize delivery of
eroded sediment to
streams
Minimize delivery of
dairy farm waste to
streams during floods
Restore natural prairie
and riparian vegetation
communities
Identify trends in drinking
water quality
Management Solutions
1. Install additional culverts.
2. Grass-seed road cut and fill
slopes.
3. Voluntary traffic manage-
ment plan.
1 . Create additional waste
storage ponds.
2. Relocate waste storage
ponds outside of 100-year
floodplain.
3. Establish vegetated biofiltra-
tion drainage features.
1. Initiate educational program
on value of riparian buffers.
2. Establish pilot projects for
vegetation restoration.
3. Develop conservation ease-
ments with private land-
owners.
1 . Expand existing water qual-
ity monitoring program with
three additional stations.
2. Conduct statistical analysis
and produce a summary
report for water quality data
from past 10 years of moni-
toring.
Cost Estimate
1. $20,000
2. $5,000
3. $1,000
1. $200,000
2. $75,000
3. $20,000
1. $5,000
2. $35,000
3. $100,000
1. $12,000
2. $10,000
Rationale
Past use of road improve-
ment plans has been effec-
tive at substantially reduc-
ing sediment delivery to
streams.
The watershed assess-
ment identified the close
proximity of waste storage
facilities to streams as the
primary factor causing ele-
vated fecal coliform levels
in the river.
The watershed assess-
ment indicated that natural
prairie and riparian com-
munities could be re-estab-
lished through the use of
buffers and restoration
techniques.
Water quality data have
been collected at a few
locations, but no summary
or evaluation of trends has
been completed.
Management
Solutions
page
73
-------
Land management options
Table 1 provides examples of management objectives and options to minimize aquatic
impact from various land uses. The key to effective aquatic resource protection often
is to use several types of aquatic management practices in concert with education and,
as necessary, regulation (EPA 1995a). A single type of management practice is seldom
sufficient to solve watershed-scale problems. A number of sources are available that
provide ideas and guidance on the use of various management solutions:
• Agriculture
- EPA (1984) describes the factors and available research relevant to selecting
appropriate pesticide BMPs.
- The National Agricultural Library (http://warp.naLusda.gov) offers a
bibliography of over 300 citations on evaluation of agricultural BMPs from
the AGRICOLA database. The NRCS also provides the National Handbook
of Conservation Practices (http://www.nrcs.usda.gov) to provide established
standards for commonly used practices to protect natural resources.
- Local NRCS offices often have Field Office Technical Guides at the county level
for watershed-specific information.
• Urban
- Metropolitan Washington Council of Governments (1990) lists non-point source
control techniques for urban areas.
- EPA (1994) describes institutional strategies for developing, revising, and
implementing runoff control programs in urbanized communities.
- EPA (1990) provides information on targeting and prioritizing BMPs in urban
areas.
• Forestry
- EPA (1993a, 1993b) provide a synopsis of BMPs used to mitigate impacts on
water quality caused by forestry operations.
• Wetlands
- EPA (1996) is a guide to stormwater BMPs for protecting wetlands in urban areas,
but many practices would also be applicable in other settings.
• Coastal Waters
- EPA (1992a) describes appropriate management measures and management
practices for each major category of non-point source pollution (agriculture,
forestry, urban, etc.).
page Management
74 Solutions
-------
Table 1. Examples of management options and solutions
Land Use Issue
Management Objectives
Management Options
Confined Animal • Design and implement systems that collect
Facilities (small solids, reduce contaminant concentrations,
units) and reduce runoff to minimize delivery of
pollutants.
• Reduce groundwater pollutant loading.
• Manage stored runoff and accumulated
solids through an appropriate waste utiliza-
tion system.
Waste storage ponds
Waste storage structure
Waste treatment lagoons
Filter strips
Grassed waterways
Constructed wetlands
Dikes
Diversions
Heavy use area protection
Lined waterways/outlets
Roof management systems
Terraces
Composting facilities
Forestry
Establish Streamside Management Areas
(SMAs) along surface waters with appro-
priate widths and harvest restrictions to:
1. maintain a natural temperature
regime;
2. provide bank stability;
3. minimize delivery of sediments
and nutrients to streams;
4. provide trees for a sustainable
source of large woody debris
needed for channel structure
and aquatic species habitat; and
5. minimize wind damage.
Specify BMPs to minimize erosion.
Develop Road Management Plans.
SMAs can vary greatly in width depending on
site-specific factors (e.g., slope, class of water-
course, type of soil and vegetation, and practice).
Minimize disturbance in SMA from heavy machi-
nery that could expose the mineral soil of the
forest floor.
Locate landings, sawmills, and roads outside
the SMA.
Establish buffers for pesticide and fertilizer
application to limit entry into surface waters.
Prevent excessive amounts of slash and small
organic debris from entering the waterbody.
Apply harvesting restrictions in the SMA to
maintain its integrity.
Agricultural Land • Minimize the delivery of sediment from
agricultural lands to surface waters.
• Design and implement a combination of
management practices to settle fine-
grained solids and associated pollutants
to minimize delivery to streams.
Adapted from EPA (1992a)
Conservation cover on land retired from production
Conservation cropping sequence
Conservation tillage
Contour farming
Cover and green manure crop
Plantings on erodible or eroding areas
Leave crop residue to provide protection from
erosion
Delayed seed bed preparation
Field border or other filter strip
Grassed waterways
Grasses and legumes in rotation
Sediment basins
Field strip-cropping
Terracing
Wetland and riparian zone protection
Management
Solutions
page
75
-------
Restoration approaches
Understanding the relationships among physical, chemical, and biological watershed
processes is critical for determining where and what type of habitat restoration will be
effective for improving stream quality and supporting valued resources. Since most
restoration projects are relatively expensive, the longevity and cost-effectiveness of the
project must be objectively evaluated.
Stream restoration can be categorized by three general approaches (EPA 1995b):
1. Upland techniques generally involve BMPs that control non-point source inputs
from the watershed (e.g., erosion and runoff control, reforestation, restoration of
native plant communities, wetland restoration).
2. Riparian techniques are applied out of the channel in the riparian corridor
(e.g., reestablishment of vegetative canopy, increasing width of riparian corridor,
restrictive fencing).
3- In-stream techniques are applied directly in the stream channel (e.g., channel
realignment to restore geometry, meander pattern, substrate composition, structural
complexity, or streambank stability).
In-stream restoration practices often need to be accompanied by techniques in the
riparian area and the surrounding watershed. For example, restoring a stream may
not only involve reconfiguring the channel form and stabilizing stream banks but can
also require planting riparian vegetation and controlling excess sediment and chemical
loading in the watershed. Details about specific restoration practices are beyond the
scope of this guide; however, Table 2 provides examples of techniques relevant to various
watershed issues.
The following sources provide further information on restoration strategies and
techniques:
• Streams
- The Restoration of Rivers and Streams: Theories and Experience (Gore 1985).
- Better Trout Habitat: A Guide to Stream Restoration and Management (Hunter
1991).
- A Classification of Natural Rivers (Rosgen 1994).
- Ecological Restoration: A Tool to Manage Stream Quality (EPA 1995b).
page Management
76 Solutions
-------
Table 2. Examples of restoration techniques for various watershed issues
Watershed Issue
Altered Stream Morphology
Sedimentation
High Streamflows
Low Streamflows
Biological Integrity
Toxicity
Water Temperature
Restoration Technique
In-stream structures (e.g., logs, boulders)
Bank protection
Promote riparian vegetation growth
Reduce sediment delivery
Restore wetlands
Stabilize banks
Modify operations of water diversion structures
Restore natural stream meanders and complexity
Increase substrate roughness
Promote riparian vegetation growth
Restore wetlands
Reduce impervious area
Reduce water withdrawals
Restore native riparian vegetation
In-stream structures (e.g., logs, boulders)
Increase channel depth with machinery
Stabilize banks
Reduce sediment delivery
Restore native riparian vegetation
In-stream structures (e.g., logs, boulders)
Remove passage barriers (e.g., diversions, culverts)
Reduce sediment delivery
Dredging
Capping material
Restore wetlands for filtering
Promote riparian vegetation growth
In-stream structures (e.g., logs, boulders)
Reduce water withdrawals
Riparian Corridors
- Stream Corridor Restoration: Principles, Processes and Practices (Federal Interagency
Stream Restoration Working Group 1998).
- A Citizens Streambank Restoration Handbook (Izaak Walton League 1995).
Wetlands
- Restoration of Aquatic Ecosystems (Brooks et al. 1992).
- Wetland Creation and Restoration: The Status of the Science (Kusler and Kentula
1990).
Management
Solutions
page
77
-------
Step 4. Create watershed management plan
Unless the watershed group is small, the management options detailed in Form Ml will
generally require review and prioritization by a group of community members larger
than the management team alone. This group, often the same people involved in
the Scoping step, will need to evaluate management options to ensure that they have
community support and the appropriate resources to be implemented. The approved
management solutions will be incorporated
Box 3. Key elements of a watershed management plan into a final watershed management plan
that prioritizes watershed actions over the
next 10 to 20 years (Box 3).
Clearly defined management objectives
Range of management options
Prioritization of management solutions
Description of rationale and uncertainties
Cost estimates and funding mechanisms
Schedule for implementation and completion
The watershed management plan should
relate directly to the strategy developed
in the Scoping process. The watershed
management plan typically involves more
specific actions than the strategy developed
in Scoping but should be consistent with the WAM goals. In some cases, the watershed
management plan may actually become the new watershed strategy.
Prioritizing management actions can be based on any combination of criteria, including
the following:
• Expected benefit to resources.
• Geographical importance.
• Critical or unique areas.
• Potential threat to resources.
• Financial impact.
• Community support.
Integrating the scientifically-based watershed priorities with community priorities is one
of the biggest challenges of the WAM process. Management options may be prioritized
initially based on the technical merits of the proposal, but community values may lead
to different priorities. Gaining community support to conduct projects in the highest
priority areas may require initially working in biologically less important areas. Projects
that engage local community support can then be used to educate the community about
working in higher priority areas even if the project is not in close proximity. Working in
page
78
Solutions
-------
a lower priority area may also serve as a pilot project to help learn about potential issues
and problems that could arise on a bigger and higher priority project.
Along with the prioritized management solutions, the watershed management plan
should include the rationale for choosing priorities or projects. A schedule for the
implementation and completion of management actions is also an important component
of the plan. Finally, the watershed management plan should be clearly summarized so
that the community can easily understand the rationale and outcomes of implementing
the plan.
Incentives for implementation
It may be difficult to reach consensus on some management solutions. Management
solutions may benefit society as a whole but may not provide an economic benefit to the
individual or organization responsible for implementing them. The limited understanding
of ecosystems may lead to uncertainties about the results of the assessment. Community
members may also disagree about the risk to important resources posed by management
practices. Some may argue for the least costly methods, others for the most effective
methods, regardless of cost. It will be important to consider incentives for participation
and voluntary, rather than regulatory, implementation of BMPs (Box 4). Table 3
summarizes potential incentives to consider in a watershed management plan.
Box 4. Cooperation and incentives in a community context
Most discussions of land management activities will involve personal communication
with a land manager, private landowner, or government representative. Cooperative
projects, cost-share programs, and technical assistance will probably be the most
commonly used incentives. Community meetings and discussions will generally be
more productive than will regulatory mechanisms for achieving watershed recovery.
The White Mountain Apache Tribe in Arizona was able to educate local ranchers
about the need to protect springs and streams important to the tribe. The tribe hired
members of the local livestock association to construct fencing around restoration
areas. The investment of time and money by local community members will help to
ensure the long-term success of these projects.
Management
Solutions
page
79
-------
Table 3. Incentives for implementing management solutions
Type of Incentive or
Motivational Factor
Description of Key Factors
Education Programs that target and tailor the message to key audiences are most
effective in causing change. Technical education about operation and ben-
efits of controls may be necessary.
Technical assistance
Through one-on-one interaction with landowners, the professional staff can
recommend appropriate BMPs for various sites. Assistance with on-site
engineering or agronomic work may be needed during the implementation
of management solutions.
Tax advantages Federal, state, or local taxing authorities can make changes to reward indi-
viduals who implement management solutions.
Cost sharing Direct payment to individuals who implement management solutions has
been effective where the cost-share rate is high enough to elicit widespread
participation.
Regulatory incentives
Direct purchase of sensi-
tive or problem areas
Non-regulatory site
inspections
A regulatory system can be established that conditions the receipt of bene-
fits on meeting certain requirements or goals.
The purchase of land for preservation, such as community-owned green-
belts or critical wildlife habitat, can be managed by groups such as the
Nature Conservancy. Costs are generally high, but direct purchase pro-
vides effective protection.
A site visit by staff of local or state agencies can be educational and pro-
vide an incentive for voluntary implementation of management solutions.
Community pressure
Direct regulation of land
use activities
Adapted from EPA (1995a)
If a community values the use of certain management solutions, land own-
ers and managers are more likely to implement them.
Regulatory programs that are simple, direct, and easy to enforce are quite
effective. Such programs can regulate land use (through zoning ordinan-
ces) or the kind and extent of activity allowed (e.g., pesticide application
rates), or they can set performance standards for a land activity (such as
retention of the first inch of runoff from urban property).
page
80
Solutions
-------
Funding
Funding is usually the greatest limitation to watershed management improvements, but
well-organized plans using the WAM approach should be eligible for many types of
private and public grants. With a little effort, sources of money can be pooled to
implement a watershed management plan. The following references are helpful for
procuring funds:
• EPA (1999) presents information on 52 federal funding sources (grants and loans)
that may be used to fund a variety of watershed protection projects. The information
on funding sources is organized into categories, including coastal waters, conservation,
economic development, education, environmental justice, fisheries, forestry, Indian
tribes, mining, pollution prevention, and wetlands.
• EPA (1992b) describes particularly effective state and local non-point source programs
and methods used to fund them.
References
Brooks, R. P., S. E. Gwin, C. C. Holland, A. D. Sherman, and J. C. Sifneos. 1992.
Restoration of aquatic ecosystems. In: M. E. Kentula, and A. J. Hairston, (eds.).
An approach to improving decision-making in wetland restoration and creation.
NAS Report. U.S. Environmental Protection Agency (EPA), Environmental
Research Laboratory, Corvallis, Oregon.
Federal Interagency Stream Restoration Working Group. 1998. Stream corridor
restoration: principles, processes and practices. U.S. Environmental Protection
Agency, EPA 841-R-98-900, Washington, D.C.
Gore, J. A. (ed.). 1985- The restoration of rivers and streams: theories and experience.
Butterworth, Stoneham, Massachusetts.
Hunter, C. J. 1991. Better trout habitat: a guide to stream restoration and management.
Island Press, Washington, D.C.
Izaak Walton League. 1995- A citizen's streambank restoration handbook. Izaak Walton
League of America, Gaithersburg, Maryland.
Management page
Solutions 81
-------
Klamath River Basin Fisheries Task Force. 1991- Long range plan for the Klamath
River Basin Conservation Area Fishery Restoration Program. U.S. Fish and
Wildlife Service, Klamath River Fishery Resource Office, Yreka, California.
Kusler, J. A., and M.E. Kentula (eds.). 1990. Wetland creation and restoration: the
status of the science. Island Press, Washington, D.C.
Metropolitan Washington Council of Governments (MWCG). 1990. A current
assessment of urban best management practices. MWCG, Washington D.C.
Rosgen, D. L. 1994. A classification of natural rivers. Catena 22:169-199-
U.S. Environmental Protection Agency (EPA). 1984. Best management practices
for agricultural nonpoint source control: IV. Pesticides. EPA 841-S-84-107,
Washington, D.C.
U.S. Environmental Protection Agency (EPA). 1990. Urban targeting and BMP
selection: an information and guidance manual for state nonpoint source
program staff engineers and managers. EPA 841-B-90-111, Washington, D.C.
U.S. Environmental Protection Agency (EPA). 1992a. Guidance specifying
management measures for sources of nonpoint pollution in coastal waters. EPA
840-B-92-002, Office of Water, Washington, D.C.
U.S. Environmental Protection Agency (EPA). 1992b. State and local funding of
nonpoint source control programs. EPA 841-R-92-003 Office of Water,
Washington, D.C.
U.S. Environmental Protection Agency (EPA). 1993a. Summary of current state
nonpoint source control practices for forestry. EPA 84l-S-93-001, Washington,
D.C.
U.S. Environmental Protection Agency (EPA). 1993b. Water quality effects and
nonpoint source control for forestry: an annotated bibliography. EPA
841-B-93-005, Washington, D.C.
page Management
82 Solutions
-------
U.S. Environmental Protection Agency (EPA). 1994. Developing successful runoff
control programs for urbanized areas. EPA 841-K-94-003, Washington, D.C.
U.S. Environmental Protection Agency (EPA). 1995a. Watershed protection: a project
focus. EPA 841-R-95-003, Office of Water, Assessment and Watershed
Protection Division, Washington, D.C.
U.S. Environmental Protection Agency (EPA). 1995b. Ecological restoration: a tool to
manage stream quality. EPA 841-F-95-007, Washington, D.C.
U.S. Environmental Protection Agency (EPA). 1996. Protecting natural wetlands — a
guide to stormwater best management practices. EPA-843-B-96-001, Office of
Water, Washington, D.C.
U.S. Environmental Protection Agency (EPA). 1999- Catalog of federal funding
sources for watershed protection. EPA 841-B-99-003, Office of Water (4503F),
Washington, D.C.
Management page
Solutions 83
-------
Form M1. Summary of management options
Issue
Management Objective
Management Solutions
Cost Estimate
Rationale
page
84
Solutions
-------
Step 5: Adaptive
Management
-------
Introduction
Adaptive management is the process by which new information about the health of the
watershed is incorporated into the watershed management plan. Adaptive management
is a challenging blend of scientific research, monitoring, and practical management that
allows for experimentation and provides the opportunity to "learn by doing." It is a
necessary and useful tool because of the uncertainty about how ecosystems function and
how management affects ecosystems. Adaptive management requires explicit consideration
of hypotheses about ecosystem structure and function, defined management goals and
actions, and anticipated ecosystem response (Jensen et al. 1996).
The results of this process are essential to validate the Watershed Assessment, to ensure
that ecosystem relationships were considered adequately in Synthesis, and to show that
management solutions have been implemented and are effective at achieving watershed
objectives.
Adaptive Management Process
Step Chart
Procedure
The objectives of the Adaptive
Management step are as follows:
• To create a system to monitor changes in
the watershed.
• To evalute trends using monitoring data.
• To modify the watershed management
plan as necessary.
Develop adaptive
management plan
Monitor
Evaluate monitoring
results
Adjust watershed
management plan
Adaptive
Management
page
85
-------
Step 1. Develop adaptive management plan
The adaptive management plan will define the process for monitoring watershed
conditions and, when necessary, modifying the watershed management plan (Box 1). The
design of the adaptive management plan is best accomplished in cooperation with policy-
level personnel with the authority to make a commitment of resources and technical
Box 1. Key elements of the adaptive personnel who can help identify scientific issues and evaluate
management plan monitoring data.
Monitoring objectives
Information needs
Available financial, technical, and human
resources
Process for evaluating monitoring results
and changing watershed management plan
Data management process
Process for communicating results of
watershed management actions
Box 2. Adaptive management in Oyster Creek, Texas
The Brazos River Authority in Texas is an example of how a long-term com-
mitment to an adaptable watershed management process can achieve sub-
stantial progress. In the Oyster Creek watershed, data collected by volun-
teers suggested that industrial discharge was impacting water quality. After
two years, industry came to better understand how they were affecting
water quality. Similarly, the volunteers learned that other non-point source
pollution would have to be addressed to solve the problems.
Industry re-engineered their discharge system to remedy the situation when
they realized that the data were good and that other causes would be eval-
uated and addressed. As a result, the partnership has continued to grow,
with industry supporting the volunteers with chemical supplies and monitor-
ing kits. In addition, they are funding a constructed wetlands pilot project.
A key to the success of this watershed management effort has been keep-
ing the community aware of progress as it is made in the watershed and
acknowledging the successes that occur.
Adapted from EPA (1997a)
The adaptive management group should clearly define
the objectives and timelines for watershed monitoring.
Using information from the Watershed Assessment and
Management Solutions processes, identify gaps in knowledge
about watershed conditions and management activities.
Prioritize the information needs so that resources can be
allocated to the most important issues. Step 2 provides more
detail on the type of monitoring to consider and resources for
designing and implementing monitoring programs.
Watershed management plans that
rely on adaptive management require
a long-term commitment of resources
to ensure success (Box 2). Financial,
technical, and other human resources
need to be outlined, along with the
specific responsibilities of each party.
The adaptive management group
should also consider establishing
criteria for modifying the watershed
management plan based on
monitoring results (Box 3). Separate
criteria will be needed for each
resource of concern, for example,
water quality, water quantity, and
aquatic life. Consideration should be
page
86
Adaptive
Management
-------
Box 3. Examples of criteria to evaluate the effectiveness of
a watershed management plan
Watershed Issue
Criteria
Stream Temperature
Bull Trout
All streams shall meet state temperature standards
in 10 years:
Class A- 16°C
Class B - 18°C
Class C - 22°C
Complete review of stream classes to ensure con-
sistency with beneficial use in 2 years
Fine Sediment • 50% reduction in road sediment delivery to Bear
Creek and Crazy Creek sub-basins in 5 years
• 25% reduction in road sediment delivery to all other
sub-basins in 5 years
Fish Passage • 90% of dams and diversions will have fish passage
structures in 5 years
• 80% of irrigation diversions will have fish screens in
2 years, and 100% will in 5 years
• Increase spawning population by 10% after 10 years
given to evaluating implementation and effectiveness at site-specific and watershed scales.
Describing the expected detail and quality of monitoring data will allow the community
to have confidence in the monitoring results and the need for changes in the watershed
management plan.
Data management and the communication of results are also important considerations
during the planning process. A great deal of data can be generated from a monitoring
program. Managing these data so that they can be effectively analyzed and summarized
is critical for maintaining interest and reporting progress on the watershed management
plan.
It will be important to highlight trends and effectively communicate successes to the
community. Consider how the group wants to promote the watershed management effort.
The following strategies can help to educate and promote better watershed management:
Adaptive
Management
page
87
-------
• Demonstration sites.
• Watershed tours.
• Community workshops.
• Information campaigns.
• Brochures.
• Web site.
• Interpretive signs.
• Student projects.
Step 2. Monitor
Three types of monitoring may be needed to meet management objectives and to evaluate
management practices:
1. Implementation monitoring (also called compliance monitoring) to determine
whether standards and guidelines are being properly followed.
2. Effectiveness monitoring to determine whether the implementation of management
solutions is achieving desired objectives.
3- Validation monitoring to determine whether the predicted results occurred and
whether assumptions about the watershed and management system were correct
(includes trend and baseline monitoring).
Further detail on designing and implementing monitoring programs can be found in the
following documents:
• General
— Inventory and Monitoring Coordination: Guidelines for the Use of Aerial Photography in
Monitoring (Bureau of Land Management [BLM] 1991).
— Statistical Methods for Environmental Pollution Monitoring (Gilbert 1987).
• Forestry
— Monitoring Guidelines to Evaluate Effects of Forestry Activities on Streams in the Pacific
Northwest and Alaska (MacDonald et al. 1991).
— Evaluating the Effectiveness of Forestry Best Management Practices in Meeting Water
Quality Goals or Standards (EPA 1994).
— Techniques for Tracking, Evaluating and Reporting the Implementation ofNonpoint
Source Control Measures: II. Forestry (EPA 1997c).
page Adaptive
88 Management
-------
• Agriculture
— Techniques for Tracking, Evaluating and Reporting the Implementation ofNonpoint
Source Control Measures: I. Agriculture (EPA 1997b).
— Monitoring and Evaluation of Agriculture and Rural Development Projects (Casley and
Lury 1982).
• Urban
— Techniques for Tracking Evaluating and Reporting the Implementation ofNonpoint
Source Control Measures: III. Urban Sources (EPA 1997d)
— Environmental Indicators to Assess Stormwater Control Programs and Practices (Clayton
and Brown 1996).
Step 3. Evaluate monitoring results
It is beyond the scope of this guide to provide detailed information on statistical analyses,
but other issues such as criteria for establishing trends and making changes in management
should be established prior to the evaluation of results (Box 3). These standards and
criteria may need to be modified based on resulting data.
Step 4. Adjust watershed management plan
A process for incorporating new information into the watershed management plan should
be outlined in the adaptive management plan. Specific time frames for revaluation
and adjustment in the watershed management plan should be established. Reevaluation
of the management plan will likely occur at 2-, 5-, or 10-year intervals to allow for
implementation and monitoring of projects and programs. Standards for applying new
information may need to be discussed by policy representatives.
Adaptive page
Management 89
-------
References
Bureau of Land Management (BLM). 1991. Inventory and monitoring coordination:
guidelines for the use of aerial photography in monitoring. BLM, Technical
Report TR 1734-1, Washington, D.C.
Casley, D. J., and D. A. Lury 1982. Monitoring and evaluation of agriculture and rural
development projects. The Johns Hopkins University Press, Baltimore, Maryland.
Clayton and Brown. 1996. Environmental indicators to assess stormwater control
programs and practices. Center for Watershed Protection, Silver Springs,
Maryland.
Gilbert, R. O. 1987- Statistical methods for environmental pollution monitoring. Van
Nostrand Reinhold, New York, New York.
Jensen, M. E., P. Bourgeron, R. Everett, and I. Goodman. 1996. Ecosystem management:
a landscape ecology perspective. Water Resources Bulletin 32(2):203-216.
MacDonald, L. H., A. W Smart, and R. C. Wissmar. 1991- Monitoring guidelines
to evaluate effects of forestry activities on streams in the Pacific Northwest and
Alaska. U.S. Environmental Protection Agency, EPA/910/9-9-001, Washington,
D.C.
U.S. Environmental Protection Agency (EPA). 1994. Evaluating the effectiveness of
forestry best management practices in meeting water quality goals or standards.
U.S. EPA 841-B-94-005, Washington, D.C.
U.S. Environmental Protection Agency (EPA). 1997a. Top 10 watershed lessons learned.
EPA 840-F-97-001, Office of Water, Washington, D.C.
U.S. Environmental Protection Agency (EPA). 1997b. Techniques for tracking, evaluating
and reporting the implementation of nonpoint source control measures: I.
Agriculture. EPA 841-B-97-010, Washington, D.C.
page Adaptive
90 Management
-------
U.S. Environmental Protection Agency (EPA). 1997c. Techniques for tracking, evaluating
and reporting the implementation of nonpoint source control measures: II.
Forestry. EPA 841-B-97-009, Washington, D.C.
U.S. Environmental Protection Agency (EPA). 1997d. Techniques for tracking, evaluating
and reporting the implementation of nonpoint source control measures: III. Urban
Sources. EPA 84l-B-97-011, Washington, D.C.
Adaptive
Management
page
91
-------
page
92
Adaptive
Management
-------
Technical Modules
-------
Community Resources
-------
Background and Objectives
It is the goal of this module to identify the natural resources valued by communities
within a watershed in order to gain a better understanding of which resources will require
protection.
The Level 1 Community Resources assessment
provides a structure for communities to identify
and evaluate their valued natural resources in the
watershed. The Level 2 assessment documents
the importance of community resources, provides the rationale for protecting those
resources, and supports the prioritization and implementation of management solutions.
"For communities to grow, they must protect the
underlying natural systems on which they are built."
EPA(1997a)
Community
Resources
page
CR-1
-------
Community Resources Module Reference Table
Critical Questions
Information
Requirements
Level 1
Methods/Tools
Level 2
Methods/Tools
CR1:
What resources in the water-
shed are significant to the
community?
CR2:
Where are community
resources located?
CR3:
What is the seasonality of the
community resource use?
CR4:
What processes or land use
activities may be impacting
community resources?
CR5:
How have community
resource conditions changed
through time?
• Anecdotal information
• Community survey
• Anecdotal information
• Watershed base map
• Natural resource maps
• Anecdotal information
• Anecdotal information
• Land use maps
• Anecdotal information
• Collect and summarize existing
information
• Collect and summarize existing
information
• Collect and summarize existing
information
• Collect and summarize existing
information
• Collect and summarize existing
information
• Detailed interviews
• Work with historian or
anthropologist
• Community use analysis
• Economic analysis
• Detailed interviews
• Field work
• Community use analysis
• Work with historian or
anthropologist
• Detailed interviews
• Field work
• Detailed interviews
• Field work
• Community use analysis
page
CR-2
Community
Resources
-------
Level 1 Assessment
Step Chart
Data Requirements
• Watershed base map
• USGS topographic maps
• Land use map
Products
• Form CR1. Categorization of community resources
• Form CR2. Trends in community resource conditions
• Map CR1. Community resources
• Community Resources report
Procedure
The primary objectives of the Community Resources
assessment are as follows:
Identify and categorize community
resources
Identify locations of community
resources
Identify seasonality of resource use
Identify trends in resource conditions
and possible impacts
Produce Community Resources report
• To identify valued community resources.
• To identify locations of community resources.
• To evaluate changes in resource conditions through time.
Step 1. Identify and categorize community resources
Through interviews with community members, identify resources that have significance
or value to the community. Many of the important community resources will have been
identified during Scoping. Resources could include such things as wildlife, fish, drinking
water, or a unique place that has a recreational or other unique value to the community.
For example, many watersheds support fish populations that have long served to attract
recreational fishermen or even commercial fisheries. Another example is a historical
feature, such as a homestead from the early 1800s that documents history of pioneer
life in the watershed. Lifelong residents may be especially helpful in identifying uses of
Community
Resources
page
CR-3
-------
natural resources in the watershed. Once a list of resources is generated, categorize them by
resource use (Box 1) and record the information in Form CR1 (Figure 1).
Box 1. Community resource categories
• Natural beauty: resources that possess aesthetic value (e.g., a scenic lookout, a waterfall, or a wetland)
• Recreation: places and resources used for entertainment
• Historical: sites that possess historical significance
• Subsistence: resources used to provide food
• Economic: resources important for community employment and revenue
• Education: places or resources of educational value
EPA (1997b)
Figure 1. Sample Form CR1. Categorization of community resources
Resource
Rocky Ford
Strawberries
Catfish
Off road vehicle trails
Copper
Beaver
Elk
Mushrooms
Patton Homestead
Gem Lake
Site
1
2
3
4
5
6
7
8
9
10
Natural
Beauty
•
•
Recreation
•
•
•
•
•
•
Historical
•
Subsistence
•
•
•
•
Economic
•
•
•
Education
•
Other
Step 2. Identify locations of community resources
Determining the location of community resources within the watershed is a critical step in
evaluating possible land management impacts to these resources (Box 2). Exact locations of
resources need not be identified if the goal is to preserve sensitive information; however, it
is important that all resource locations be identified in some way. Identifying the presence
of sensitive resources in a broad area or with coded symbols can maintain the security
of important sites should the community wish to not widely advertise their existence or
location.
page
CR-4
Community
Resources
-------
Box 2. Sources of information on community resource locations
Local Town Hall, County Office, or Planning Board
• Local land use maps that show whether land is used for housing, commercial
enterprises, agriculture, or open space
• Tax maps that show public or private ownership of land
• Flood insurance maps
State Environmental Agency
• Wetland delineation maps
• Watershed maps that show the waterbodies, wetlands, and other components of
the watershed
• Land use maps
• Aerial photos
• Aquifer delineation maps
State Conservation or Land Acquisition Group
• Land use maps
State Wildlife and Fisheries Department or Department of Natural Resources
• Maps of state and local recreation areas
• Maps showing the distribution of different plants and animals throughout the state,
including rare and endangered species, non-native species, and critical habitat
Federal Government
• Maps showing natural features of all parts of the United States (USGS)
• Maps of coastlines and ocean waters (The National Oceanic and Atmospheric
Administration [NOAA])
• Maps of floodways and flood hazard areas (FEMA)
EPA (1997a)
To create Map CR1, add the locations of community resources to a base map of the
watershed (Figure 2). Topographic maps that cover the watershed area can also be used.
The community resources map can be a rough schematic or a more detailed map using
GIS technology.
Community
Resources
page
CR-5
-------
Figure 2. Sample Map CR1. Community resources
Step 3. Identify seasonality of resource use
Natural resources important to a community are often available only at specific times of
the year (Box 3). For example, berries are gathered during the summer, and deer and elk
are hunted during the fall. Understanding the seasonality of resource use provides a greater
opportunity to connect land use impacts to community resource conditions.
Step 4. Identify trends in resource conditions and possible impacts
page
CR-6
An important and easily available source of information on community resource condition
trends is interviews with individuals who have lived in the community for many years.
Information on conditions or trends, such as bad smelling drinking water or an obvious
decrease in fish populations, can be obtained from long-term residents or from historical
documents on community life. Another important source of information is state or federal
restrictions on using community resources. Examples include restrictions on fish or water
consumption, the federal listing of an endangered wildlife species, or the classification of
a parcel of land as critical habitat.
Community
Resources
-------
Use the information collected to
identify trends in resource conditions
and summarize the trends in Form
CR2 (Figure 3).
For each resource, also identify land
use impacts on resource conditions.
While many of the potential land
use impacts will have been identified
during the Scoping process, further
investigation can help to refine the
connection between land uses and
resource conditions. The sources of
resource impairment should also be
recorded in Form CR2.
Box 3. Seasonality of resource use, an example
from the Sol Due watershed
Quileute Annual Cycle
(approx. dates)
January
March
April
May
June
Shaffer et al. (1995)
Sol Due Watershed Activities
• Hunting small mammals:
land otter and beaver
• Steelhead fishing
• Root digging: ferns
• Skunk cabbage
• Camas
• Salmonberry and thimbleberry
• Horsetail sprouts
• Bird hunting
• Cedarbark
• Spring (chinook) salmon
• Blueback (sockeye) salmon
• Labrador tea and herbs
Figure 3. Sample Form CR2. Trends in community resource conditions
Resource
Native
Vegetation
Wetlands
Trout
Trend
• Decrease in native
plant species in
local park
• Decrease in acreage
• Loss of plant diversity
• Decreased populations
• Loss of adequate
habitat
Sources of Impairment
• Increased
recreational use
• Road construction
• Agriculture
• Peat harvesting
• Urban development
• Grazing contributing
sediment to prime
spawning habitat
Related Modules
• Vegetation
• Vegetation
• Erosion
• Channel
• Vegetation
• Hydrology
• Water Quality
• Aquatic Life
Community
Resources
page
CR-7
-------
Step 5. Produce Community Resources report
The Community Resources report should summarize the location and use of important
community resources and discuss possible impacts to and trends in resource conditions.
Elements of this report include the following:
1. Description of Community Resources
• Community cultural story (Box 4)
• General location and use of community resources
• Changes in resource use and conditions over time
2. Summary of Results
• Conclusions
• Map CR1. Community resources
• Form CR1. Categorization of community resources
• Form CR2. Trends in community resource conditions
3- Sources of Information
• Methods
• References
• Assumptions
• Confidence in the assessment
• Further information needs
CR_8
Community
Resources
-------
Box 4. Deer Creek cultural story
The Stillaguamish River watershed lies 40 miles north of the Seattle area in Washington
State and is approximately 1,200 square miles. The Stillaguamish flows off the western
foothills of the Cascade Mountains down to Puget Sound. The river and its tributaries support
four salmon species, steelhead trout (sea-run rainbow trout), sea-run and resident cutthroat
trout, and many other species of fish. These fish were once plentiful but have suffered from
degradation of their habitat and over-harvest during the past century. The estuary of the
Stillaguamish also supported abundant fish and shellfish populations.
The watershed is the historic home of the Stillaguamish Tribe of Native Americans. The
tribe depended on the abundant fish resources in the watershed for their food and for
trade. Salmon were harvested almost year round and were eaten fresh, cooked over alder
campfires, and dried. Their roe (eggs) were considered a delicacy and a good source of oil
and protein. The Stillaguamish culture honored the salmon and steelhead, which provided a
central focus for their myths, legends, and religion.
Europeans began to settle the area in the late 1800s; however, they tended to settle in the
lowlands near Puget Sound. They also found food, sustenance, and sport in the salmon and
steelhead of the watersheds.
In 1911, a world famous author and sportsman, Zane Grey, journeyed to the Pacific
Northwest to fish for steelhead in a famous tributary stream of the Stillaguamish River, Deer
Creek. He later wrote of traveling all day by train into the forests north of Seattle until he
finally reached the town of Oso at the mouth of Deer Creek. He then climbed aboard a
logging train and headed into the Deer Creek watershed. Arriving finally, and climbing over
moss covered downed trees, he described Deer Creek as the most crystal clear, emerald
green trout stream he had ever seen.
Today, Deer Creek runs chocolate brown year round. Steelhead fishing has been closed for
decades, and the Deer Creek steelhead are perhaps extinct. The salmon and steelhead runs
of the Stillaguamish River are now some of the weakest in the region, and most years no
fishing by sportsmen or tribal fishermen is permitted.
Community
Resources
page
CR-9
-------
CR-10
Level 2 Assessment
The purpose of the Level 2 Community Resources assessment is to collect additional
information on the importance of the resources identified in the Level 1 assessment.
Resources in the watershed might have social, cultural, or recreational significance, or
they might support the economy or quality of life in the community. Documenting
the importance of community resources will provide the rationale for protecting those
resources and will support prioritization and implementation of management solutions.
A useful source of information on evaluating the benefits provided by community
resources is Community-Based Environmental Protection: A Resource Book for Protecting
Ecosystems and Communities (EPA 1997a).
Social and Cultural Importance of Community Resources
Describing the social and cultural significance of watershed resources will help the
community to better document their cultural heritage, understand their relationship
to the natural environment, and communicate with others about preserving valued
resources. The following methods can be used to collect information on the cultural
significance of community resources:
• Perform personal interviews with natives, long-term residents, and other community
members.
• Perform fieldwork to locate community resources.
• Work with a historian, anthropologist, or archaeologist familiar with the region.
Topics that could be addressed include the following:
• Describe traditional uses of resources, such as plants, fish, and wildlife for food or
waterways for transportation. In addition to existing resources, consider resources
that have been degraded or lost.
• Provide additional detail on the cultural or historical significance of locations in the
watershed.
Community
Resources
-------
Economic Importance of Community Resources
Another way to establish the importance of community resources is to identify, and
if possible to quantify, their contribution to the local economy. The economic value
of community resources is most obvious when the community's economy is based on
agriculture or on the extraction of natural resources, such as fish, shellfish, trees, coal, and
oil. Other ways that natural resources can contribute to a community's economy include
the following:
• Natural areas can be important for recreation-based businesses that attract tourists,
anglers, hunters, birdwatchers, and hikers.
• Lakes, parks, and preserves can enhance property values.
• Wetlands, forested areas, and floodplains can provide natural flood water storage and
water filtration, reducing the need for capital projects to replace these functions, such as
levees and seawalls or water treatment plants.
Table 1 lists possible indicators and sources of information for documenting the economic
value of community resources.
Importance of Community Resources for Quality of Life
Natural resources can also contribute to a community's quality of life, although this type of
resource value is more difficult to quantify than economic value. Examples of benefits that
can be provided by natural resources include the following:
• Natural beauty.
• Human health and safety.
• Recreation.
• Sense of community.
• Educational value.
Table 2 lists possible sources of information for documenting the importance of
community resources for quality of life.
Community
Resources
CR-11
-------
Table 1. Information sources for assessing the linkages between natural resources and the local economy
Overall
Assessment
Objective
Sample Indicators
Possible Sources of Information
Assess
dependence of
local tax revenues
on ecosystems
Annual revenue from fees for use of parks and
beaches
Local parks and recreation department, local revenue department
Assess • Annual revenues from and/or employment in
dependence of local outdoor recreational businesses (e.g., boat
local economy on rentals, nature tour guides, birdwatching, and
nature-based cross-country skiing centers)
recreation • Annual number of fishing or hunting licenses
issued in the county
• Annual number of "activity days" for various
categories of outdoor recreation (e.g., fishing,
hunting)
Local merchants
Local chamber of commerce
State fish and wildlife department
State Comprehensive Outdoor Recreation Plans (contact state
tourism and recreation agency)
U.S. Fish and Wildlife Service (USFWS), National Survey of Fishing,
Hunting, and Wildlife Associated Recreation, published every six years
Local chamber of commerce
Assess need for
clean water for
industrial use
Use of water by food processors, breweries, etc.
Local water authority
Local chamber of commerce
Local business leaders or representatives of relevant companies
Assess impact of • Relative cost of otherwise similar houses located
ecosystem health near and several blocks away from a local park
on residential • Qualitative indicator based on home buyer and
property values realtor opinions on premium paid for properties
located near environmental amenities (e.g.,
clean rivers, parks)
Local registry of deeds
Survey of recent home buyers in the area
Local realtors
Assess trends in • Urban Sprawl Index: rate of conversion of open
commercial and land to suburban/urban development
residential • Percentage of building permits in downtown/
development urban core vs. non-urban or suburban areas
Municipal/county/state land use planning offices
Local building and permits office
Assess local
dependence on
"extractive" natural
resource-based
activities
Revenues of local forest products industry
relative to revenue in all industries
Employment in local forest products industry
relative to employment in all industries
Revenues of local commercial fishery relative to
revenue in all industries
Employment in local commercial fishery relative
to employment in all industries
U.S. Department of Commerce, Bureau of the Census, County
Business Patterns, phone: (301) 457-4100
U.S. Department of Commerce, Bureau of Economic Analysis,
Regional Economic Information System, phone: (202) 606-9900
USFS, Forest Statistics, by state
U.S. Department of Commerce, Bureau of the Census, County
Business Patterns, phone: (301) 457-4100
U.S. Department of Commerce, Bureau of Economic Analysis,
Regional Economic Information System, phone: (202) 606-9900
National Marine Fisheries Service (NMFS) in the U.S. Department of
Commerce maintains county-level data on landings and value of catch
Local chamber of commerce
Assess
sustainability of
local resource-
based industries
EPA <1997a)
Ratio of the amount, health, and diversity of
timber regrowth to timber cut
Stability in numbers of juvenile and young-of-
year in fish population over time
USFS, Forest Statistics, by state
NMFS data (see above)
page
CR-12
Community
Resources
-------
Table 2. Information sources for assessing the linkages between natural resources and local quality of life
Overall Assessment
Objective
Sample Indicators
Possible Sources of Information
Characterize
importance of
ecosystem to local
education
Number of school field trips to
natural areas
Number of visitors to local
arboretum, bird sanctuary, or state
and national parks
Local schoolteachers
Management office of relevant
organization (e.g., arboretum)
Assess flood control
services provided by
local wetlands
Qualitative indicator based on
flooding history of area with
wetlands and similar areas where
wetlands have been lost to
development
Newspaper archives
Local land use officials
Local emergency management
officials
Characterize
dependence of town
on local surface and
groundwater
Percentage of household water
supply from local sources
Local public works department
Regional water supply authority
Assess availability of
land for recreation
Acres of land/open space available
for recreation per 1,000 people in
the community
Local land use officials
Local or state parks and recreation
officials
Characterize level of
recreational activity
dependent upon
ecosystems
EPA (1997a)
Annual number of "activity days"
for various categories of outdoor
recreation (e.g., rafting and
kayaking, fishing, hunting, and
visitor days to local resorts and
campgrounds)
Trends in beach closures or fishing
advisories
Fate and effects of sanitary waste
and refuse on ecosystems
USFWS, National Survey of Fishing,
Hunting, and Wildlife Associated
Recreation, published every six
years
State Comprehensive Outdoor
Recreation Plans, contact state
tourism and recreation agency
County or municipal records for
sanitary treatment and waste
removal from recreation site
Community
Resources
page
CR-13
-------
References
Shaffer, J. A., B. Warner, and J. Powell. 1995- Sol Due Pilot watershed analysis: Cultural
module. Olympic National Forest, Olympia, Washington.
U.S. Environmental Protection Agency (EPA). 1997a. Community-based environmental
protection: A resource book for protecting ecosystems and communities. EPA
230-B-96-003, Washington, D.C.
U.S. Environmental Protection Agency (EPA). 1997b. Cultural ecosystem stories: A
guide to preparing natural resource case studies (DRAFT). EPA, American Indian
Office, Washington, D.C.
page
CR-14
Community
Resources
-------
Form CR1. Categorization of community resources
Resource
Site*
Natural
Beauty
Recreation
Historical
Subsistence
Economic
Education
Other
' Identify locations on Map CR1, Community resources
Community
Resources
page
CR-15
-------
Form CR2. Trends in community resource conditions
Resource
Trend
Sources of Impairment
Related Modules
page
CR-16
Community
Resources
-------
Aquatic Life
-------
Background and Objectives
Streams, lakes, and wetlands provide habitat for cold and warm water fish, amphibians,
and the species on which they depend. The Aquatic Life module provides a procedure
for evaluating the needs of valued aquatic species and the condition of stream, lake, and
wetland habitats. In this module, the term valued aquatic species refers to a single species,
several species, or a functional group or guild of species that were identified for assessment
during Scoping. The assessment is designed to determine how the flows of water, heat,
pollutants, and other stream inputs are affecting the habitat and other needs of valued
species.
For a Level 1 assessment the analyst collects and summarizes existing information on the
population status, distribution, and ecological needs of the species. This information is
then used to develop working hypotheses regarding how the species and habitat in the
watershed have been impacted. Using existing habitat data, habitat in the watershed is
evaluated based on the species' ecological needs. The results of the habitat evaluation are
used to support or disprove the working hypotheses or to identify the need for further
data collection and assessment.
The module also provides information on methodologies that can be used for a Level 2
assessment. While Level 1 assessment relies primarily on existing information, Level 2
assessment is used when more extensive data collection and analyses are needed.
•.atic Life
page
AL-1
-------
Aquatic Life Module Reference Table
Critical Questions
Information
Requirements
Level 1
Methods/Tools*
Level 2
Methods/Tools*
AL1:
What are the valued
aquatic species that are
present in the watershed?
AL2:
What are the distribution,
relative abundance,
population status, and
population trends of the
aquatic species?
AL3:
What are the
requirements of various
life history stages of the
aquatic species?
AL4:
What are the habitat
conditions for the aquatic
species?
AL5:
What connections can be
made between past and
present human activities
and current habitat
conditions?
• Information on species
and distribution
• Historical and current
population estimates
and species distribution
information
• Scientific literature
• Regional information
and regional models
• Scientific literature
• Existing habitat survey
information
• Historical information
on watershed
conditions
• Current information on
watershed conditions
• Aerial photos
• Consult watershed and
species experts
• Evaluate existing
information
• Investigate watershed
history
• Consult management
agencies, watershed
experts, and species
experts
• Collect existing regional
information
• Identify the habitat
requirements (by life
stage, season, etc.)
• Consult with species
experts
• Develop descriptions of
current habitat
conditions
• Develop and apply
evaluation criteria
• Summarize watershed
history
• Consult watershed
experts
• Analyze aerial photos
• Evaluate existing habitat
survey information
• Collect watershed-
specific information
• Population modeling
• Bioassessment methods
• Instream Flow
Incremental
Methodology or habitat
suitability indices
analysis
• Suitability criteria
development
• Regional models
• Collect watershed-
specific information
• Modeling
• Modeling
• Expert system
Overlap exists between Level 1 and Level 2 methods. Often, the difference consists of the level of effort
expected or whether existing information is used or the collection of new information is needed. Most
Level 2 methods incorporate actions that are identified here as Level 1 methods (for example, consulting
watershed or species experts).
page
AL-2
atic Life
-------
Level 1 Assessment
Step Chart
Data Requirements
• Map of streams, lakes, and wetlands within the watershed.
• Land use map or recent aerial photos.
• Information on the population status, population trends,
and distribution of the aquatic species. Sources for this
information include agency records, species distribution
maps, basin management plans, stock management
plans, historical and current population assessments, and
endangered species assessments and descriptions.
• Information on aquatic habitat conditions from state and
federal agency records and existing habitat surveys.
• Information on dams, diversions, stream channelization,
and alteration of lakes or wetlands. Much of this
information may be historical.
• Information on existing or proposed listings under the
ESA or under state endangered species laws.
• Professional opinions and information from resource
professionals with expertise in the region, the watershed,
or the aquatic species.
• Scientific literature on species' ecological needs.
Products
• FormALl. Summary of hypotheses
• Map ALL Aquatic species distribution
• Map AL2. Aquatic habitat distribution
• Map AL3- Aquatic habitat conditions
• Aquatic Life report
Collect aquatic species and
habitat information
Summarize aquatic species
population information
Summarize ecological needs
of aquatic species
Develop working hypotheses
Evaluate current habitat conditions
Reevaluate hypotheses
Produce Aquatic Life report
'.atic Life
AL-3
-------
Procedure
Step 1. Collect aquatic species and habitat information
Collect available historical and current information on the valued species from federal,
tribal, state, and local agencies and other community members. The information
requirements are summarized in the Data Requirements section, above. Tracking
down available information can be a time-consuming part of the process. Information
gathering should also include interviews with agency biologists and any other individuals
with expertise in either the assessment area or the aquatic species.
Step 2. Summarize aquatic species population information
Summarize the information from Step 1 focusing on the population status of the aquatic
species and its distribution. Also summarize any available information about trends in
population or distribution. The amount of detail for each of these topics may vary.
Population information may be available only for an area larger than the watershed in
question (e.g., a river basin or multi-state area) or may be very detailed (e.g., years of creel
census information for a particular lake). Information may also be anecdotal (e.g., great
declines in the range of a given species over the last 150 years). It may be that consulting
watershed experts will yield the best information available.
At this point it may be useful to create Map AL1, the distribution map for the aquatic
species under study. It may also assist other analysts to have this map.
Step 3. Summarize ecological needs of aquatic species
Using information that was gathered in Step 1, summarize descriptively or in a table
the important life history patterns of the aquatic species and the species' ecological
needs during each life stage (Box 1). This information, together with the distribution
information, will help in determining the areas of the watershed that are important
for different life history requirements or times of year. The information on life
history requirements will also contribute to the development of hypotheses and habitat
evaluation criteria. Examples of life stages include spawning, incubation, rearing, adult,
and in- and out-migration. Requirements should be represented by factors that are
measurable (e.g., water temperature) rather than those that, while important, are less
likely to be measurable (e.g., genetic diversity).
page
AL-4 Aquatic Life
-------
Box 1. Life history preferences for stream-resident brook trout (Salvelinus fontinalis)
Life stage
Habitat preferences
Timing
Spawning
Incubation
Winter habitat
Summer habitat
0.1 - 3" gravel, redd sizes
<2ft2
No flood flows (causes redd
scouring) or fine sediment
inputs (smothers eggs)
Pools with cover, interstitial
spaces in cobble/gravel
substrates
Water temperatures 10°C -
19°C, adequate food (primarily
insects, some fish), escape
cover
September - November
Winter
Water temperatures < 4°C
Water temperatures > 4°C
Meehan (1991), Stoltz and Schnell (1991)
Step 4. Develop working hypotheses
Summarize important historical events and specific situations of concern
Using historical information and management plans, summarize past events and current
situations in the watershed that are likely to have had an impact on either the population
of the aquatic species or on habitat conditions. Summaries can be in text or table format.
Following are examples of events or situations that could affect species or habitats:
• Historical presence or absence of a species (such as beaver) in a watershed.
• Historical introduction of an exotic species and subsequent interactions between native
and introduced species.
• Past management actions such as hatchery operations or stocking programs.
• Disturbance events such as land clearing, dam construction, alteration of lakes or
wetlands, floods, or fires that may have contributed to current habitat conditions.
Also consider situations such as changes in inputs of heat (e.g., loss of stream shading),
sediment (e.g., landslides), streamflow (e.g., dams or diversions), and riparian conditions
(e.g., grazing, land clearing). Consultation with other analysts at this stage may be very
useful.
Channel
Hydrology
Vegetation
Water Quality
Historical
Conditions
'.atic Life
page
AL-5
-------
Channel
Vegetation
Water Quality
page
AL-6
Develop working hypotheses about impacts on aquatic species and habitats
Using the information collected and summarized in the previous steps, develop working
hypotheses about cause-and-effect relationships between historical actions or current
situations, a change in inputs to the aquatic system, and potential impacts on the aquatic
species or its habitat.
It is not expected that enough information will be available to allow statistical testing of
hypotheses in the scientific sense. Rather, the process of developing hypotheses is used
to focus the assessment process and facilitate discussions. Communication among the
Aquatic Life, Channel, Vegetation, and Water Quality analysts is essential to incorporate
findings collected for one module into the assessment of another (e.g., water quality
information as a habitat parameter), to identify data gaps, and to refine hypotheses.
A suggested format for summarizing working hypotheses is provided as Form ALL
Examples of general hypotheses are provided in Figure 1; the analyst should be able to
generate more specific hypotheses than those shown.
Step 5. Develop habitat evaluation criteria
Generate a table of proposed habitat evaluation criteria based on the life history
requirements of the aquatic species. Because of the importance of conclusions that will
be developed using the criteria, community members and watershed experts should
participate in criteria development whenever possible. This will provide a chance for
feedback on variables used and the critical values selected.
Habitat evaluation criteria are defined in this module as characteristics of the environment
in which an organism lives that can serve as effective indices of habitat condition and
indicators of human-caused change. Criteria should be quantitative if possible. General
categories of habitat criteria include the following:
• Floodplain characteristics.
• Riparian characteristics.
• Streambank characteristics.
• Stream channel, lake, and wetland characteristics.
• Streambed substrates.
• In-stream wood debris.
• Habitat quantity.
• Water quantity and quality.
atic Life
-------
Figure 1. Sample Form AL1. Summary of hypotheses
Species
Stream-dwelling fish
or amphibians
Stream-dwelling fish
or amphibians
Stream-dwelling fish
or amphibians
A native trout
Brook trout
Sub-basin
Beaver River
Trout Creek
Prairie Creek
Deer Creek
Spring Creek
Description
Beavers were common
in the watershed prior
to settlement and are
uncommon now.
A severe fire burned
the sub-basin in 1977.
Riparian trees were
removed along the
mainstem (1960-1975);
current riparian
vegetation is pasture
grasses.
Stocking of brook trout
was widespread in the
late 1 9th and early 20th
centuries. Brook trout
are established and will
displace native trout.
Past management has
relied on hatchery
stocking. Current goals
protect naturally
spawning populations.
Hypothesis
Pool, backwater, and wetland habitats formerly
created and maintained by beavers may be less
common now than they were in the past. This may
have had the following impacts on the aquatic
species. . . (depending on the species preference
for or dependence on these habitats)
Sediment or wood debris may have entered the
stream channel, increasing sediment load and
changing channel conditions. This may have had
the following impacts on the aquatic species...
(depending on the species preference for or
dependence on the channel conditions that result
from these inputs)
Changes in the riparian vegetation may have
caused water temperature changes, changes in
in-stream habitat conditions, or stream channel
shifts. This may have had the following
impacts on the aquatic species... (depending on
the species water temperature preferences or
tolerances and habitat requirements)
The distribution of native trout may cover a
smaller area now. This may have had the following
impacts on the aquatic species... (impacts
could include population numbers, breeding
opportunities, higher fishing pressure, etc.)
Because the management goal now supports
natural spawning, the condition of the spawning
areas may be critical for maintaining population
numbers. Stream survey information indicates
the following about conditions of spawning
habitat... This may have had the following impacts
on the aquatic species... (depending on the
species preference for or dependence on these
conditions')
Source (include
watershed expert
as appropriate)
Historical records
Agency records
Aerial photos
Historical records
Basin management
plan
Identify regional criteria or develop literature-based criteria
For some species, appropriate habitat criteria and associated survey methods
may already have been developed by management
agencies. If regionally appropriate habitat evaluation
criteria cannot be located for the aquatic species,
criteria should be developed based on scientific
literature and consultation with regional managers
and biologists (Box 2). Interviews with watershed or
species experts will provide valuable information.
'.atic Life
Box 2. Guidance for developing habitat evaluation criteria
Bovee (1986) presents an excellent discussion of methods
to develop habitat suitability criteria using watershed
experts' opinions and scientific literature for situations in
which collection of additional field data is not possible.
page
AL-7
-------
Box 3. Sources of habitat suitability models
Information on habitat suitability models can
be obtained from regional offices of the USGS
Biological Resources Division, particularly
the Midcontinent Ecological Science Center,
Fort Collins, Colorado (www.mesc.usgs.gov).
The regional office in Lafayette, Louisiana
(National Wetlands Research Center) may
also have some documents available online
(www.nwrc.gov).
Habitat criteria have been summarized for many species
by the USFWS and the USGS Biological Resources
Division based on investigations presented in the scientific
literature (Box 3). These documents can suggest both
appropriate criteria for consideration and a starting point
for determining regionally appropriate values and ratings
in discussion with watershed experts.
The example provided in Box 4 illustrates how habitat
evaluation criteria can be developed based on scientific
literature. Both critical thinking and common sense will be
Box 4. Development of habitat evaluation criteria based on scientific literature
Stuber et al. (1982) provide the following information on habitat conditions for largemouth bass (Micropterus
salmoides) in rivers.
Life stage
Parameter
Good habitat
conditions
Moderate habitat
conditions*
Poor habitat
conditions
Adult, juvenile, fry Dissolved oxygen
Adult, juvenile
Adult, juvenile
Adult, juvenile
Adult, juvenile
Incubation
Fry
All
Turbidity (suspended
solids)
Percentage pool habitat
Percentage cover in
pools
Summer water
temperature
Water temperature
Water temperature
Salinity
> 8 mg/L
< 25 ppm
> 60%
40 - 60%
24 - 30°C
13-26°C
27 - 30°C
< 1.66 ppt
4 - 8 mg/L
25-100ppm
< 4 mg/L
> 100 ppm
< 20%
<15°Cand>36°C
<10°Cand >30°C
<15°Cand>32°C
> 4 ppt
* Moderate values are listed here if provided by Stuber et al. (1982).
Using the habitat conditions table for largemouth bass, habitat evaluation criteria could be developed for discussion
with watershed experts. For example, dissolved oxygen criteria could be developed fairly simply. Levels greater than
8 mg/L could be rated "good," levels between 4 and 8 mg/L "moderate," and levels less than 4 mg/L "poor." For two
other parameters, percentage pool habitat and summer water temperature, the "good" and "poor" ranges could be
easily defined, but the question of how to assign a "moderate" rating might require more discussion. A "moderate"
rating for percentage pool habitat could be assigned to the 30 - 50% range, and a "moderate" rating for summer
water temperatures could be assigned to the 15.5 - 23.5°C range (assuming typical summer water temperatures
are not less than 15°C).
page
AL-8
atic Life
-------
necessary during this process. The goal is to identify a small number of appropriate criteria
for each life stage of the aquatic species. Too many criteria can confuse the assessment.
Focus should remain on those criteria that watershed experts agree are important to
specific life stages and for which information has been collected. Criteria should also
be measurable to allow comparison among sub-basins (e.g., stream shading and average
tree height would be more useful than
would a general description of riparian
function). The criteria should help to
illustrate where land use and human
interaction with the landscape have the
Box 5. Development of human disturbance criteria
potential to change habitat conditions or
alter population status.
Develop human disturbance criteria
In addition to the evaluation criteria for
specific habitat conditions, it might be
appropriate to use an index of human
disturbance, such as road density or
percentage impervious surface (Box 5).
In a watershed with a mix of agricultural, urban, and suburban land
uses, the identified issues are delivery of sediment and increased
runoff to the stream during winter storms and fragmentation of
the riparian corridor by roads, pipelines, and powerlines. Aerial
photos can be used to make a count of road stream crossings
per mile, which will indicate the number of delivery points for
sediment and runoff and the relative amount of disturbance in
the riparian corridor. Specific criteria for evaluating the level of
human disturbance can be developed by comparing the number of
road stream crossings per mile with regional values or by making
comparisons across sub-basins or land use categories
Mayetal. (1997)
Step 6. Evaluate current habitat conditions
Use the information collected in Step 1 and the criteria developed in Step 5 to evaluate
the current habitat conditions in the watershed. For each stream reach, lake, wetland, or
sub-basin for which information is available, habitat is evaluated for the species or life stage
that occurs there. The evaluation can also group species as appropriate or analyze
groups of stream reaches, lakes, or wetlands where a particular species or life stage is
important (e.g., spawning areas). In addition, the question of access into and out
of particular habitats should be evaluated as necessary (considering both in- and out-
migration, as appropriate). The analyst should focus both on typical habitats and habitats
of special concern. Describing overall conditions is as important as, or more important
than, describing unique or uncommon situations.
Compile a summary of available data on habitat conditions and apply the habitat
evaluation criteria. An example of a format that could be used to summarize data is
provided in Figure 2.
'.atic Life
page
AL-9
-------
Figure 2. Sample habitat data summary form
Reach ID
Distance
sampled
Pool Characteristics
Percent pool Percent cover
habitat Rating in pools Rating
Substrate Characteristics
Rating Sub- Rating for
Dominant for spawning/ dominant spawning/
substrate adult habitat substrate adult habitat
Water
Quality
Sample ID
Reach ID
where
sample
was taken
Water Quality Characteristics
Dissolved Turbidity Salinity Additional
oxygen (NTU), (ppt), parameter,
(mg/L), Rating Rating Rating Rating
Water Temperature Characteristics
Summer water
temperatures Incubation period
(°C) water temperatures
(mean, range) Rating (°C)(mean, range) Rating
Several criteria for a particular stream reach might fall into the "moderate" category.
While it may be fairly straightforward to look at the criteria in the "poor" category
and hypothesize connections between human-caused inputs and stream processes, the
meaning of the "moderate" ratings can be less clear. Values that fall into a moderate range
may indicate that conditions are changing from poor to good or from good to poor. The
analyst can look for supporting evidence from other parameters in similar categories, such
as other indicators of riparian condition or of in-stream habitat quality.
There may be situations in which only general information, not specific data, is available
for a parameter considered important by the analyst or the watershed experts. In that
situation, professional judgments can be made and indicated as such in the report. In
addition, data gaps that were identified should be noted.
page
AL-10
atic Life
-------
Habitat information should be evaluated critically. Habitat surveys are a snapshot of
dynamic aquatic and riparian systems. Data may have been inconsistently collected, and
sampling protocols will tend to change over time. Also, data may not be summarized in
a manner helpful to the analyst. For example, data collected between two access points
may cover several channel types. Events occurring after a survey (e.g., a flood) may
have left the habitat in a different condition than data indicate. Collaboration between
analysts will be the best source of information to assess these situations.
Channel
Hydrology
Vegetation
Water Quality
Step 7. Reevaluate hypotheses
Using the results of the habitat evaluation, reevaluate the working hypotheses developed
in Step 4 (Box 6). Determine whether the information collected on current habitat
conditions supports the hypotheses or indicates that the hypotheses should be revised.
Also identify any hypotheses for which further data collection or input from other
analysts will be needed. The hypotheses will be discussed with the other analysts during
Synthesis.
Box 6. Sample revaluations of hypotheses using conclusions from habitat evaluation
Hypothetical example 1
Shading levels are good in three of five sub-basins in the Little Pine watershed. The hypothesis is
that, for the other two sub-basins, summer water temperatures may be less than optimal and may
be limiting fish population numbers. Comparing available water temperature data and habitat criteria,
it appears that summer water temperatures are higher than preferable but not lethal in the two sub-
basins. No fish population or distribution data were available. Given that the hypothesis cannot be
proved or disproved with existing information, the analyst then states the suspected problem: Shading
levels are less than optimal in the two sub-basins, with possible negative impacts to fish habitat or
populations from high water temperatures. This would then generate the following question for other
analysts during Synthesis: Are stream shading levels in the two sub-basins likely to be increasing,
decreasing, or staying the same? What effects might this have on future water temperatures?
Hypothetical example 2
Bullfrogs, an introduced non-native species in the western United States, are now present throughout
the Bull Run watershed. Because it is well known that bullfrogs are very successful predators on native
frogs, the following hypothesis was developed: Native frogs are now rarer than in the past and may
only exist above barriers to bullfrogs. Native frog distribution information for the watershed shows
that native frogs are in fact rare, except in one stream system where bullfrogs have been excluded.
The analyst then revises the hypothesis by adding the idea that the small stream system should be
identified as refugia for the native frogs.
•.atic Life
page
AL-11
-------
Step 8. Produce Aquatic Life report
Produce maps
At least two and possibly three maps will be generated from the assessment. Map AL1
will present species distribution. An option is to also present historical distribution if it
will contribute to the Synthesis discussions.
Maps AL2 and AL3 will present habitat distribution and a summary of habitat
conditions. The habitat distribution and condition information could also be combined
on one map, depending on the amount of information to be presented. The information
included on the maps will vary with the aquatic species, its specific habitat requirements,
and the geomorphology of the watershed. Examples of information that could be
presented include the following:
• Spawning habitat, rearing habitat, adult habitat, and juvenile habitat (there may be
"important/primary" and "less important/secondary" categories).
• Critical habitat (e.g., location of refugia or the only occurrence of a habitat type in
the watershed).
• "Important/primary" habitat that is in degraded condition or in very good condition.
• Areas where habitat is in "naturally poor" condition (e.g., due to geology or soils).
• Areas where in- or out-migration is blocked.
• Dams, diversions, or irrigation withdrawals.
• Other topics of concern identified by the analyst (e.g., water quality problems).
Not all topics on this list will necessarily be presented on all maps. Whether one or two
maps are needed to present the summary of habitat condition will depend on the number
of aquatic species and the complexity of the situation. Often cartographic requirements
that limit the amount of information easily included on a single map will prevail. Maps
can be separated by concerns for a particular species, concerns during a specific time of
year (such as winter, summer, or spawning periods), or other appropriate concerns. It
may be helpful to present the channel segmentation and classification on one of these
Channel maps to assist in the development of hypotheses regarding channel and habitat responses
to inputs such as sediment, water, and vegetation.
page
AL-12 Aquatic Life
-------
Produce report
Produce a report summarizing information gathered and evaluation results. Critical
questions should be kept in mind while developing the report. The report should include
the following elements:
• A description of the valued aquatic species, their population statuses and trends, and
their current distribution.
• A table summarizing life history requirements, which will be helpful for other analysts
during Synthesis.
• A description of the historical abundance of and use of the watershed by the aquatic
species.
• A description of the habitat evaluation criteria and the sources and methods used to
develop the criteria.
• A summary of current habitat conditions within the watershed. Descriptions can be
separated based on channel type, species or life stage, or sub-basin.
• A discussion of the hypotheses developed and evaluated.
• Identification of data gaps.
• A summary of the level of Box 7. Sample summaries of confidence in the assessment
confidence in the assessment and
in the various conclusions that
have been reached (Box 7).
The report could also identify areas
that may be critical habitat for a
particular life stage, reaches with
water quality concerns, reaches of
high-quality habitat or of degraded
habitat, and obstructions and
blockages to migratory species or life
stages. Comparisons could also be
made between current conditions and
descriptions of reference conditions
for the particular ecoregion, if they are available.
Confidence is high in amphibian distribution information in the
wetlands of the Bog Creek sub-basin because of recent extensive
baseline surveys.
Confidence is low to moderate for assessment of habitat conditions
for brook trout in the Big Pine Creek sub-basin. No habitat surveys
have been performed, and the assessment was made using aerial
photos.
Confidence is low regarding issues about water temperature for small
lakes in the Ruby Valley watershed. No water temperature data were
available, although watershed experts expressed concern about the
potential for high summer water temperatures.
•.atic Life
page
AL-13
-------
Level 2 Assessment
This section presents a selection of Level 2 assessment tools for aquatic species and aquatic
habitat. Some methods allow the analyst to study the species of concern (or group of
species) directly by assessing population size or species associations. Others use a measure
of habitat availability or quality to assess ecosystem health or impacts from land use. Other
methods incorporate approaches from population modeling and ecosystem theory.
This list of methods is not exhaustive. The analyst will need to consult with experts to
determine whether a particular method is appropriate for the area under analysis and the
topic of investigation.
Some of the methods presented below are fairly simple, while others require more time
and resources. The analyst should consider whether extensive analysis is warranted
by the magnitude of the problem under study and is feasible with the resources and
information available. It is possible that a simpler approach will generate results with
sufficient confidence to develop conclusions and policy recommendations. It should also
be recognized that the science of ecosystem analysis is evolving, and tools and methods are
continually under development.
Use of Aquatic Habitat Models
Instream Flow Incremental Methodology (IFIM)
The IFIM was developed by the USFWS to allow predictions of habitat quantity and
quality for various aquatic species in riverine environments (Bovee 1982). It was developed
for use in water allocation negotiations and operation of controlled rivers. Modeling is
based on a combination of hydraulic factors measured in the river and general habitat
preferences offish species and life stages.
The strength of this approach is that it allows a quantitative estimate of gains and losses
in fish habitat as flows incrementally change. One difficulty is that it can be expensive
to collect the physical measurements and fish observations needed to generate a good
quality model.
AL-1 4 Aquatic Life
-------
Habitat Suitability Indices (HSI)
The USFWS has also developed a series of descriptive models called HSIs for
many species, including many fish and other aquatic-dependent species. The HSIs
are developed from research literature and expert reviews and are intended to aid
in identifying important habitat variables. They are hypotheses of species-habitat
relationships, and users are expected to recognize that the veracity of model predictions
will vary between places and will depend on the extent of the database for individual
variables (Stuber et al. 1982; Terrell et al. 1982). This assessment tool can also be used
in a Level 1 assessment.
The strength of these models is that they provide a quantitative index of habitat quality.
They also present good summaries of what is known about the habitat requirements and
preferences of a particular species. The analyst can then compare this information with
the specific situation under analysis, choose the factors that are important, and devise
the appropriate analysis approach. HSIs are different from the "expert system" approach
outlined below because they require a higher level of expertise.
Use of an Expert System
Expert systems are designed to allow a less-experienced analyst access to the thinking and
experience of those with greater expertise on the topic under consideration. They can
be a series of questions posed to a group of experts, a dichotomous key, or a computer
program. The strength of this approach is that the experience of experts can be accessed
in a structured format. One problem with this approach is that it lends itself to a
"cookbook" analysis, which might neglect an important habitat situation that was not
addressed.
An example of an expert system is presented in MacDonald et al. (1991). They present an
expert system that, through a series of questions, allows the investigator to generate a list
of physical and biological parameters to be used in the design of water quality monitoring
to investigate impacts from land use practices. An example of a dichotomous key for
determining limiting factors for coho salmon freshwater life stages is presented by Reeves
et al. (1989). This approach relies on field data for habitat parameters as well as estimates
of adult escapement needs (see limiting factors discussion in the "Use of an Ecosystem
Approach" section, below).
page
'.aticLife AL-15
-------
Use of Bioassessment Methods
Bioassessment methods vary widely, although all generally use measures of population
size or makeup (e.g., number of species) to assess ecosystem health and response to land
use activities. Examples include a simple presence/absence study for a single species and
investigations of predator-prey relationships or other trophic-level interactions (Hauer and
Lambert 1996). Multi-species sampling for fish and macroinvertebrates is also used to
develop comparisons of population or habitat conditions within regions (Plafkin et al.
1989, Karr 1991).
Strengths of this approach include the fact that the aquatic species itself—rather than an
indicator such as habitat conditions or water quality—is under study. Also, regional values
for fish and macro invertebrate species assemblages have been generated for many states or
ecoregions (e.g., Kerans and Karr 1994). Difficulties with this approach include potentially
high costs in time and resources and difficulty in finding reference sites to define good
habitat conditions with which to compare the area under study.
Use of Population Model Predictions
The topic of population modeling is too large to address in this module; however, existing
information on population status and trends for the aquatic species of concern will always
be useful to the analyst. In addition, incorporation of population model predictions may
also be considered by the analyst. The analyst should be informed about model strengths
and weaknesses as well as the limits of both the data used in model development and the
range of model predictions.
Use of an Ecosystem Approach
Watershed analysis is itself an approach that takes an integrated view of ecosystem processes
and biological responses. Scientists have developed other methods or approaches that
incorporate aspects of watershed analysis, such as assessment of watershed processes, with
approaches drawn from ecosystem theory. A recent example, presented by Lestelle et al.
(1996), uses salmon as an indicator species for ecosystem health. Like watershed analysis,
this type of method works to integrate watershed processes, population dynamics and the
effect of management actions. Another ecosystem approach is a "limiting factor analysis,"
which attempts to identify which habitat component constrains or limits the size of a
page
AL-16 Aquatic Life
-------
population. An example of a limiting factor analysis method is presented by Reeves et al.
(1989) and discussed in the "Use of an Expert System" section, above. Like population
modeling, the topic of integrating ecosystem approaches and watershed analysis is too large
to address in the module.
A strength of an ecosystem approach is that it builds on past research and integrates many
of the dynamic factors that limit populations. One difficulty with this type of approach is
that information requirements and analysis may become very complex.
page
'.aticLife AL-17
-------
References
Bovee, K. D. 1982. A guide to stream habitat analysis using the Instream Flow
Incremental Methodology. Instream Flow Information Paper #12. U.S. Fish and
Wildlife Service, FWS/OBS-82/26, Washington D.C.
Bovee, K. D. 1986. Development and evaluation of habitat suitability criteria for use
on the Instream Flow Incremental Methodology. U.S. Department of the Interior
Fish and Wildlife Service, National Ecology Service, OCLC No. 15021448,
Washington, D.C.
Hauer, F. R., and G. A. Lambert (eds.). 1996. Methods in stream ecology. Academic
Press, San Diego, California.
Karr, J. R. 1991. Biological integrity: a long-neglected aspect of water resources
management. Ecological Applications l(l):66-84.
Kerans, B. L., and J. R. Karr. 1994. A benthic index of biotic integrity (B-IBI) for rivers
of the Tennessee Valley. Ecological Applications 4(4):768-785.
Lestelle, L. C, L. E. Mobrand, J. A. Lichatowich, and T. S. Vogel. 1996. Applied
ecosystem analysis - a primer. Ecosystem diagnosis and treatment (EDT).
Bonneville Power Administration, BPA/2753A/1996, Portland, Oregon.
May, C. W, E. B. Welch, R. R. Homer, J. R. Karr, and W Mar. 1997- Quality
indices for urbanization effects on Puget Sound lowland streams. Washington
Department of Ecology, Publication 98-04, Water Resources Series, Technical
Report # 154, Olympia,Washington.
MacDonald L. H., A. W Smart, and R. C. Wissmar. 1991- Monitoring guidelines
to evaluate effects of forestry activities on streams in the Pacific Northwest
and Alaska. U.S. Environmental Protection Agency, EPA/910/9-91-001,
Seattle, Washington.
Meehan, W H. (ed.). 1991. Influences of forest and rangeland management
on salmonid fishes and their habitats. American Fisheries Society, Special
Publication 19, Bethesda, Maryland.
page
AL-18 Aquatic Life
-------
Plafkin, J. L, M. T. Barbour, K. D. Porter, S. K. Gross, and R. M. Hughes.
1989- Rapid bioassessment protocols for use in streams and rivers; benthic,
macroinvertebrates and fish. U.S. Environmental Protection Agency, EPA/440/
4-89/001, Washington, D.C.
Reeves, G. H., E H. Everest, andT. E. Nickelson. 1989- Identification of physical
habitats limiting the production of coho salmon in western Oregon and
Washington. U.S. Department of Agriculture Forest Service, General Technical
Report PNW-GTR-245, Corvallis, Oregon.
Stoltz, J., and J. Schnell (eds.). 1991. Trout. Stackpole Books, Harrisburg, Pennsylvania.
Stuber, R. J., G. Gebhart, and O. E. Maughn. 1982. Habitat suitability index
models: largemouth bass. U.S. Fish and Wildlife Service, FWS/OBS-82/10.16,
Ft. Collins, Colorado.
Terrell, J. W, T. E. McMahon, P. D. Inskip, R. F. Raleigh, and K.L. Williamson.
1982. Habitat suitability index models: Appendix A. Guidelines for riverine and
lacustrine applications offish HSI models with habitat evaluation procedures.
U.S. Fish and Wildlife Service, FWS/OBS-82/10.A, Washington D.C.
page
'.aticLife AL-19
-------
Form AL1. Summary of hypotheses
Species
Sub-basin
Description
Hypothesis
Source (include
watershed expert
as appropriate)
page
AL-20
atic Life
-------
Water Quality
-------
Background and Objectives
The goal of the Water Quality assessment is to evaluate the status of specific waterbodies
as reflected by various water quality parameters related to the health of community
resources (Figure 1). The evaluation process will not only aid in identifying existing
water quality problems but will also identify the possible sources that may have caused
the problems and suggest changes in management practices or restoration possibilities.
Figure 1. Water quality assessment
Waterbodies
Streams
Lakes
Reservoirs
Estuaries
1
Beneficial Uses
Fisheries
Recreation
Domestic
i
KeyP
Temperature
TSS
DO
Industrial
Agricultural
Cultural
!
arameters
PH
Nitrogen
Phosphorus
Natural and Land
Use Disturbance
* 1
Watershed Processes y
Hydrology Management
Erosion and Restoration
\
Source Input
Water Energy
Nutrients Pathogens
Pathogens
Pesticides
Toxicants
Biological
Regional Interagency Executive Committee (RIEC) and
Intergovernmental Advisory Committee (IAC) (1995)
Level 1 Water Quality assessment is a screening process that characterizes the status of
water quality in the watershed and identifies potential sources of impacts. The assessment
can also identify which waterbodies are at risk and where more in-depth assessment is
needed to address specific pollution problems.
Level 2 Water Quality assessment can be conducted for stream segments or waterbodies
that have been identified as impaired by the Level 1 assessment or that are on the State
Water Quality
WQ-1
-------
303(d) list. Level 2 assessment provides detailed examination of pollution sources and
a complete description of water quality problems. Targeted stream sampling plans may
be developed to pinpoint pollution sources and provide quantitative information on the
degree of impact from a specific source. Level 2 assessment is also helpful when a higher
level of certainty is required, such as when developing TMDLs or restoration strategies.
page
WQ-2
Water Quality
-------
Water Quality Module Reference Table
Critical Questions
Information
Requirements
Level 1
Methods/Tools
Level 2
Methods/Tools
WQ1:
What are the beneficial uses
of water resources?
WQ2:
What water quality parame-
ters have not met the
standard and for what time
period?
WQ3:
How much difference exists
between current water qual-
ity and reference conditions?
WQ4:
What causes temperature
impairment?
WQ5:
What causes fish consump-
tion advisories?
WQ6:
What causes fish kills?
WQ7:
What causes excessive algae
growth or eutrophication?
• State, tribal, and local documenta-
tion
• 303d list
• EPA, state, and tribal standards
• Monitoring data
• Additional information required
for modeling
• Map and other description of the
reference conditions
• 303d list
• EPA, state, and tribal standards
• Monitoring data
• 303d list
• Change in water and land use
• NPDES data
• Weather data
• Flow data
• Aerial photos of riparian conditions
• Stream characterizations
• Water quality data, especially
PCBs, metals, and organic com-
pounds.
• Reports of previous advisories
• NPDES data
• Fish tissue analysis results
• Benthic sediments and pathogens
data
• DO, temperature
• Chemical spills, and mining
activities
• Fish species
• Stream characteristics
• Nutrient concentrations
• Flow data
•pH
• NPDES data
• 303d list
• Land uses
• Data on nitrogen and phosphorus
concentrations
• Temperature
• Turbidity
• Flow
• Chorophyll-a
• Solar radiation
• Survey community members
• Interview government agencies
• Compare the available data to
standards
• Trend analysis
• Summarize and compare availa-
ble data
• Describe the reference condi-
tions
• Survey various users
• Identify possible point and non-
point sources
• Identify diversions and new
water uses
• Identify land use change and any
abnormal climate conditions
• Identify possible point and
nonpoint sources
• Interview water users
• Compare water quality data to
available standard for the fish
species
• Identify potential pollutant
sources affecting fish survival
• Examine data for excessive
nutrient concentration and
aquatic weeds
• Identify potential nutrient
sources
• Statistical analysis
• Modeling
• Additional monitoring
• Toxicity test
• Field surveys
• Monitoring
• Stream classification
• Mixing and heat balance cal-
culations
• Computer simulations
• Toxicity analysis
• Bioaccumulation analysis
• Computer simulation for
dynamics of DO, tempera-
ture, pH, and algae
• Predict primary productivity
• Computer simulations
Water Quality
WQ-3
-------
Water Quality Module Reference Table (continued)
Critical Questions
Information
Requirements
Level 1
Methods/Tools
Level 2
Methods/Tools
WQ8:
What can cause beach or swim-
ming area closures and other
pathogen problems?
WQ9:
What conditions lead to exces-
sive turbidity?
WQ10:
What causes foul odors?
WQ11:
What adverse impacts on wet-
lands might have resulted from
water quality impairments?
WQ12:
What are the other possible
major sources causing water
quality problems?
• Data from Health Depart-
ment
• Beach locations
• Livestock facilities and septic
systems
• Flow data
* Hydrological data
* Pathogen attenuation rates
• Land use and soil type data
• Urban construction sites
• Road data
• Agricultural practices
• Wind data
* Hydrological data
• Watershed characteristics
• NPDES data
* Industrial facilities
* Livestock production facilities
• Water surface change
• DO
• Flow rate
• Volatile compound
• Data on sediments, nutrients,
and toxic chemicals
• Water balance
• Water temperature
• Change in water salinity
* Acid mine drainage
• Chemical spills
• Irrigation return flows
• Landfill sites
• Connection to storm sewer
* Leaking underground storage
tanks
* Atmospheric deposition
• Acid rain
• Groundwater
• Monitoring data
* Identify potential pathogen
sources of agricultural and
urban origin.
• Identify sources such as indus-
trial processes, wetlands, waste-
water treatment plants, failed
septic systems
* Mapping historical and exist-
ing wetland areas
• Evaluate changes in vegetation
sensitive to water quality
* Identify locations of the poten-
tial sources
* Pathogen die- off and trans-
port calculation
* Computer simulations
• Erosion and sediment deliv-
ery models
• WEPP, RUSLE and other
computer simulation models
• Calculate volatilization rate
* Identify odorous substances
* Modeling and computer
simulations
• Additional water analysis for
toxic substances
* Pathway analysis
* Additional monitoring
• Modeling and computer
simulation
• Examine land fill records
* Check irrigation flow quality
data
page
WQ-4
Water Quality
-------
Background and Objectives
Step Chart
Data Requirements and Sources
Data requirements
Identify water quality standards and criteria
Identify indicators of impairment
Analyze water quality data
The following is a brief list of the data required to begin the
Water Quality assessment. Some of the maps and data may not be
available for a given watershed or may not be necessary depending
on the scope of water quality issues.
• USGS topographic map of the watershed (1:24,000 scale).
• GIS stream layer (if available).
• Copies of existing water quality data and reports.
• 305(b) list reports and inventories of state waterbodies.
• 303 (d) list of state waterbodies not in compliance with the
Water Pollution Control Act of 1972 (Clean Water Act
[CWA]).
• NPDES permit compliance data for point source discharges.
Data sources
There are numerous sources of water quality data currently
available, and access to the web has greatly facilitated the
distribution of information (Tables 1 and 2). Water quality
information may be accessed in different forms, such as raw data, databases, and reports.
Reports and databases generally prove to be better sources than simple raw data. Reports
offer the advantage that previous synthesis and analysis efforts have been made. Details
on how the data were collected may also be provided. Most commercial databases are
compiled based on the original data collected with QA/QC protocols. Although raw data
may be available locally, it will most likely need to be processed before analysis.
Define scope of assessment
Identify beneficial and cultural water uses
Identify potential pollution sources
Produce Water Quality report
Water Quality
WQ-5
-------
Table 1. Internet sources for water quality information
Web site
EPA Surf Your Watershed
EPA Unified Watershed Assessments
EPA and NRCS Clean Water Action Plan
EPA STORE!
USGS Water Resources Data
USGS National Water Quality Assessment
Program
USGS National Mapping Program
Association of State and Interstate Water
Pollution Control Administrators
NRCS National Resources Inventory
Web address
http://www.epa.gov/surf2
http://www.epa.gov/cleanwater/uwafinal/
appc.html
http://www.epa.gov/cleanwater/links.html
or
http://www.nhq.nrcs.usda.gov/
cleanwater/links.html
http://www.epa.gov/owow/storet/
http://water.usgs.gov/data.html
http://water.usgs.gov/nawqa/
nawqa_home.html
http://mapping.usgs.gov/
http://www.asiwpca.org
http://www.nhq.nrcs.usda.gov/NRI/
Description
• Location of watershed
• Assessment of watershed health
• State and tribal Unified Watershed
Assessments and contacts
• EPA regulated facilities and pollutant
discharges
• Links to community groups
• Links to and descriptions of federal
programs for collecting water quality
information
• Links to federal, state, and private
sites with environmental data and other
information
• Large national database of water quality
information
• Links to water flow, water quality, and
climate data
• Describes the status and trends in the
quality of the nation's groundwater and
surface water resources
• Contains topographic maps, spatial data,
and remote sensing data
• Links to state water quality programs
• Statistically-based sample of land use
and natural resource conditions and
trends on non-federal lands in the United
States
Products
• Form WQ1. Summary of water quality conditions
• Map WQ1. Water quality impairments
• Water Quality report
Procedure
The objectives of the Water Quality assessment are as follows:
• To identify the beneficial and cultural uses of water resources.
page
WQ-6
Water Quality
-------
Table 2. Local sources of water quality information
Data Source
State 303(d) and 305(b)
reports
Section 31 4 and 319
lists
State and local soil
conservation districts
State and tribal health
departments
University libraries
Description
• 303(d) reports list water quality impaired waterbodies and
parameters exceeding standards.
• 305(b) reports characterize general water quality
conditions and programs to restore and protect waters.
• Section 31 4 lists indicate the water quality status of public
lakes, including point and non-point source pollution
problems.
• Section 319 lists were created in 1989 and characterize
water quality problems in coastal areas.
• Expertise and information may be available on the effects
of agricultural practices such as grazing, irrigation, and
waste management.
• Expertise and information may be available on drinking
water, septic tanks, and community health.
• Unpublished reports, dissertations, and theses may be
available in science and engineering libraries.
• To summarize water quality parameters related to the resource uses.
• To assess the trends and status of important water quality parameters.
• To identify sources of water quality impacts.
Step 1. Define scope of assessment
Identify the key personnel and assign responsibilities for the Water Quality assessment
team. Team members may be from within the lead tribal organization or may consist of
external community members or experts.
A preliminary plan of action should be developed that succinctly defines the assessment
objectives. The stream segments or sub-basins to be assessed, general time-frame for
completion, anticipated data collection problems, and responsibilities for final products
should all be discussed. Collecting, analyzing, and reporting water quality data that have
very little or no impact on the Water Quality assessment can waste a significant amount
of time.
Step 2. Identify beneficial and cultural water uses
Identify all legally defined beneficial uses and other potential beneficial uses (e.g., cultural)
of the water resources within the watershed. The beneficial use of each stream segment
Water Quality
WQ-7
-------
Table 3. Examples of beneficial uses and related
water quality parameters
Community
Resources
Historical
Conditions
should be identified from the mouth of the
mainstem upstream to the tributaries. A
list of federally recognized beneficial uses is
shown in Table 3- Beneficial uses should be
listed in Form WQ1.
After determining the beneficial uses
currently assigned to each stream segment
in the watershed, the Water Quality
assessment team can begin to discuss
whether these designations make sense
given the team's knowledge of the
watershed. The key questions in Box 1 are
a useful guide to ensure that all relevant
issues are addressed during this step.
The CWA directed states to establish water
quality standards related to the intended
uses (or beneficial uses) of surface waters.
Some states have completed beneficial use
status and attainability assessments for
various rivers. The beneficial uses outlined
in the CWA do not include cultural
or ceremonial water uses, but the CWA
does allow flexibility in identifying new uses or biota categories. The analyst
should coordinate with the Community Resources and Historical Conditions analysts
to identify potential beneficial
uses of cultural significance.
Establishing new beneficial uses
Beneficial use categories
Fish and wildlife
Agriculture
Public water supply
Navigation
Industry
Hydropower
Recreation
EPA (1994)
Key pollutant parameters
TSS
Turbidity
DO
Toxic chemicals
Temperature
Bacteria
TSS
Toxic chemicals
TSS
Turbidity
Toxic chemicals
Bacteria
Sediments
TSS
Turbidity
Turbidity
TSS/sediment yield
Turbidity (aesthetics and
safety)
Bacteria
Box 1. Key questions for beneficial use identification
will often require supporting
documentation of the following:
• Historical use.
• Locations of cultural
significance.
• Cultural use protection
standards.
Where are the surface waters, lakes, ponds,
estuaries, groundwater aquifers, wetlands, etc.?
What are the current identified beneficial uses?
What are the historical beneficial uses?
What are the key parameters related to the
beneficial uses?
Were any of the beneficial use changes caused
by water quality?
page
WQ-8
Water Quality
-------
Step 3. Select parameters and assemble data
Select water quality parameters
Based on the identified beneficial and cultural uses, determine which water quality
parameters will need to be evaluated. Tables 4 and 5 list parameters that typically need to
be evaluated for a variety of beneficial uses; the importance of each parameter for each use
is rated High, Moderate, or Low.
The parameters for which data are most commonly required are as follows:
• Temperature.
• Total suspended solids (TSS).
• Dissolved oxygen (DO).
• pH (acidity).
• Nutrients (e.g., nitrogen and phosphorus).
• Pathogens (e.g., fecal coliforms).
• Pesticides.
• Metals (e.g., cadmium, chromium, copper, lead, mercury, and zinc).
• Other toxic chemicals.
• Biological conditions.
More extensive definitions of these parameters can be found in introductory water quality
texts. The relationships between parameters and community resources are briefly described
in the following sections.
Temperature
Elevated stream temperatures can stress and cause behavioral changes in fish populations
and other biota. Warmer water temperatures can change aquatic community assemblages,
reduce growth rates, and increase disease.
Although land use impacts generally elevate stream temperatures, vegetation removal may
cause cooler water temperatures during the winter. Cooler winter water temperatures may
reduce growth offish and can also cause the formation of anchor ice that smothers aquatic
life in the stream substrate.
Temperature can also affect a number of other important water quality parameters.
Gas solubility decreases with increasing temperature, resulting in generally lower DO
Water Quality WQ-9
-------
Table 4. Parameter selection for water quality assessment in relation to water uses
Variables
Temperature
Color
Odor
Suspended Solids
Turbidity
Conductivity
Total dissolved solids
PH
DO
Chlorophyll a
Ammonia
Nitrate/Nitrite
Phosphorus
Total organic carbon
Chemical oxygen demand
Biochemical oxygen demand
Sodium
Potassium
Calcium
Magnesium
Chloride
Sulphate
Fluoride
Boron
Cyanide
Metals
Arsenic/Selenium
Oil and Hydrocarbons
Organic Solvents
Phenols
Pesticides
Fecal Coliforms
Total Coliforms
Pathogens
•o
ackgroun
lonitoring
m t
H
M
H
L
M
H
H
L
L
M
M
M
M
H
L
L
L
M
M
L
BJ
Q S DC aj ±: _l g
L
M M
M M
H H
M M
L L
L H L
L L M
L L
M M
L
H M
L L
M
L H
L L
L
L H
L L
M L L
M L
L
H L L
M L L
M
H
M
M
H H H
H H L
H H L M
o = £
.« ? 1 53
II C J Sri ^ § S
o« o.2> =ai o2 o
Q. O) .±(0 Q.O. LLO. Q-
H L
L M
H
M M L M H
M M
H M H H L
H M M H H
L H L
L L
M L
L
M
H L L H
L L L H
M M L H H
M M M H L
L L M
L L L H
L
L
L
H
Chapman (1996)
page
WQ-10 Water Quality
-------
Table 5. Parameter selection for water quality assessment in relation to additional water uses
Variables
Temperature
Color
Odor
Suspended Solids
Turbidity
Conductivity
Eh
pH
Dissolved Oxygen
Hardness
Ammonia
Nitrate/Nitrite
Phosphorus
Total organic carbon
Chemical oxygen demand
Biochemical oxygen demand
Sodium
Potassium
Calcium
Magnesium
Chloride
Sulphate
Fluoride
Boron
Cyanide
Metals
Arsenic/Selenium
Oil and Hydrocarbons
Organic Solvents
Phenols
Pesticides
Fecal Coliforms
Total Coliforms
Pathogens
11
o o
i i
L
L
M
H
M
L
L
H
L
H
H
H
L
M
H
M
L
L
L
H
L
L
M
M
L
L
H
H
H
c 3=
BJ O
•e =
—i ^
_j k.
L
L
L
M
M
L
L
H
L
M
M
M
L
M
M
M
L
L
L
M
L
L
M
L
H
L
L
M
3
~3
O
O)
M
L
M
H
M
L
L
H
L
H
H
H
L
L
H
M
L
L
L
H
L
L
M
H
H
M
M
o
It
0. 0
-r, 4> % %
^J J \J (/)
= 0) £ C
v> i 5 j=
L
M
H H
M H
H
L
M
M H
L L
H
H
M
H
H L
L L
M
H
M
M H
H
H
V)
_o
1
1^
L
L
L
H
H
L
L
H
L
L
L
L
L
L
H
L
L
L
L
H
L
L
L
L
M
L
L
L
L
BJ
O
'*••
3
"BJ o
U BJ
II
0 Q.
L
L
L
L
L
L
H
H
L
M
M
M
M
H
M
L
L
L
L
M
M
M
L
L
M
L
M
H
H
H
c
O
V '43
c o
S Q.
L
L
L
H
H
L
L
L
L
L
L
L
L
L
L
L
L
L
L
L
H
L
H
L
Chapman (1996)
Water Qual
WQ-11
-------
concentrations and reaeration rates. With temperature increases, chemical and biochemical
reaction rates typically increase markedly and mineral solubility increases. Most organisms
have distinct temperature ranges within which they can reproduce and compete effectively.
Total suspended solids (TSS)
TSS are defined as the particles in the water column that are larger than 2 microns
in diameter. In streams, the majority of TSS are fine sediments or algae. Laboratory
procedures for measuring TSS involve time-consuming processes of filtering, drying,
cooling, and weighing. Because TSS can be related to the turbidity of the water, turbidity
is used in many cases to evaluate the concentration of fine particulate material suspended
in the water column. Turbidity can be quickly measured by determining light transmission
in water.
Sediment may directly affect fish by causing gill abrasion or fin rot. Sediment can
indirectly impact aquatic biota by reducing habitat through blanketing of fish spawning
and feeding areas, by eliminating sensitive food organisms, or by reducing sunlight
penetration to aquatic plants, thereby impairing photosynthesis.
Suspended sediment also decreases recreational values, adds to the mechanical wear of
water supply pumps and distribution systems, and adds to treatment costs for water
supplies. Suspended sediment may also provide a mechanism for transport of pesticides
or other toxic compounds.
Dissolved oxygen (DO)
DO is defined as the amount of oxygen dissolved in water. The presence of oxygen is
of fundamental importance in maintaining aquatic life and the aesthetic quality of waters.
Low DO concentrations may harm fish and aquatic biota. Fish tolerance of low DO
levels varies by species, growth cycle, acclimation time, and temperature. Cold water fish
(e.g., salmon and trout) require higher DO concentrations than do warm water fish and
biota. The preferred DO level for trout is generally greater than 5 mg/L. Rough fish
such as carp and catfish can survive at oxygen levels as low as 2 mg/L and also tolerate
warmer water.
pH (acidity)
pH represents the concentration of hydrogen ions in water and thus indicates the acidity of
the water. As water becomes more basic, pH increases; as water becomes more acidic, pH
decreases. pH affects the reaction and equilibrium relationships of many chemicals. Many
page
WQ-12 Water Quality
-------
biological systems function only in relatively narrow pH ranges (typically 6.5 to 8.5)- Fish
and other aquatic species prefer a pH near neutral (7) but can withstand a pH in the range
of about 6 to 8.5- Low pH in water inhibits enzymatic activity in aquatic organisms. The
toxicity of many compounds can also be altered if the pH is changed. The solubility of
many metals, as well as other compounds, is affected by pH, resulting in increased toxicity
in the lower pH range.
Nutrients—phosphorus and nitrogen
Both phosphorus and nitrogen are essential nutrients for the growth of aquatic vegetation.
Phosphorus is essential for the growth of algae and other aquatic organisms. Serious
problems such as algae blooms and fish kills have resulted when excess phosphorus exists
in the aquatic environment.
Nitrogen is a complex element that can exist in seven states of oxidation. From a
water quality standpoint, the nitrogen-containing compounds that are of most interest are
organic nitrogen, ammonia, nitrate, and nitrogen gas. Table 6 summarizes the generally
reported forms of nitrogen.
Table 6. Summary of nitrogen forms
Total Nitrogen
Total Inorganic
Nitrogen Nitrate
Readily available for aquatic
Total Organic
Total Kjeldahl Nitrogen (TKN)
Ammonia Dissolved Particulate
plant growth Must undergo microbial degradation
to become available
Nutrient enrichment of surface waters may cause excessive algae and aquatic plant growth.
This creates large diurnal oxygen fluctuations due to excessive DO production during
daylight hours followed by excessive consumption of oxygen (mainly through plant die-
off) when photosynthesis is not occurring. Seasonal die-off of vegetation due to frost
may also create large oxygen demands and suffocate fish and aquatic organisms. Physical
impediments to fishing and boating and operation of water supply facilities can also be
affected when vegetation becomes so overgrown that leaves and roots clog motors and
Water Quality
WQ-13
-------
intakes. Nitrate contaminants in drinking water significantly above the drinking water
standard (10 mg/L) may cause methemoglobinemia (a blood disease) in infants and have
forced closure of several water supplies. High ammonia concentrations in water are also
toxic to fish and cause an odor problem.
Pathogens
Pathogenic bacteria, protozoa, and viruses include infectious agents and disease-producing
organisms normally associated with human and animal wastes. Waterborne pathogens
can be transmitted to humans or animals through drinking water supplies, direct contact
recreation, or consumption of contaminated shellfish. Bacterial pathogens of concern
include V. cholerae, Salmonellae, and Shigella. Pathogenic protozoan eggs and cysts have
been linked to Giardia lambia and Entamoeba histolytica (amoebic dysentery). Viruses
ingested from water can lead to diseases such as hepatitis (Thomann and Mueller 1987).
Detection methods for pathogenic bacteria are severely limited because of the difficulty in
isolating a small number of cells. Consequently, in spite of problems establishing direct
correlations, coliform groups can serve as indicators of pathogens. Fecal coliform bacteria
behave similarly to common enteric pathogens, and a close relationship exists between the
growth and survival of fecal coliform and both Salmonella and Shigella.
Relationships between the total coliform bacteria group and pathogens are not considered
to be quantitative. Because of the occurrence and interference of nonfecal bacteria and
their differential resistance to chlorination, more accurate approaches involving the fecal
coliform and fecal Streptococci groups are required.
Pesticides
Pesticides are most commonly used in agricultural applications for the control of weeds and
pest organisms. The presence of these substances in water is troublesome because they are
toxic to most aquatic organisms and many are known or suspected carcinogens. Potential
impairments from pesticides include damage to aquatic fauna and concerns for human
health (contamination of domestic water supply or fishery). Concentration levels rather
than overall loadings are most important. Contamination of groundwater by organic
chemicals can occur through leaching.
Metals
Heavy metals are a group of elemental pollutants including arsenic, cadmium, chromium,
copper, lead, mercury, nickel, selenium, and zinc. Industries such as electroplating, battery
manufacturing, mining, smelting, and refining have been identified as potential sources of
page
WQ-14 Water Quality
-------
heavy metals. Metals may enter surface waters either dissolved in runoff or attached to
sediment or organic materials. Metals can also enter groundwater through soil infiltration.
Metals can have toxic effects on humans, fish, wildlife, and microorganisms. Since metals
do not readily decay, their persistence in the environment is a problem potentially
contributing to long-term habitat and public water supply degradation. A principal
concern about metals in surface water is their entry into the food chain at relatively low
concentrations and their bioaccumulation over time to toxic levels. High concentrations
of arsenic can cause dermal and nervous system toxicity effects; high concentrations of
cadmium can cause kidney effects; and high concentrations of chromium have been linked
to liver and kidney effects. Lead can result in central nervous system damage and kidney
effects and is also highly toxic to infants and pregnant women. High concentrations of
mercury can cause central nervous system disorders and kidney effects; high concentrations
of selenium have gastrointestinal effects; and high concentrations of silver can cause skin
discoloration.
Other toxic chemicals
Thousands of industrial and petroleum processing chemicals such as plasticizers, solvents,
waxes, polychlorinated biphenyls (PCBs), and polycyclic aromatic hydrocarbons (PAHs)
make up the final group of toxic substances. Alkyl phthalates, chlorinated benzenes, PCBs,
and PAHs are broad subcategories in this group. Some chemicals are carcinogenic directly
to humans, while others affect fish, aquatic organisms, or plants within the water column
or in the benthic sediment layer.
Biological conditions
Because water quality problems often manifest themselves in terms of fish or organism
health, many states and the EPA are promoting data collection on fish and benthic
organism communities while conducting water quality assessments. While biological data
are generally considered to be indicators of water quality rather than specific parameters,
it may be cost-effective to compile this data and water quality data simultaneously. The
biological data may be critical in associating pollutant concentrations with long-term
detrimental effects. However, a great deal of uncertainty exists when interpreting this
type of data.
Assemble water quality data
Assemble all of the relevant water quality data available for the watershed. It is very
important to keep the assessment objectives in mind to keep the team focused. Try to
avoid collecting information outside the scope of the project.
Water Quality WQ-15
-------
Identify data deficiencies
Problems exist when comparing data sets collected by different entities. For example, the
data may have been collected using different methodologies and QA/QC protocols or at
different times and locations. To facilitate the combination of data from various sources,
team members will need to become familiar with the designation of stream segments and
waterbodies within their watershed.
An important part of creating the database will be judging the validity of the
data. Laboratory errors, data translation errors, improper chain of custody procedures,
and several other independent sources of error can affect results. Undoubtedly, data
interpretations will need to be made, but they should be made carefully by experienced
professionals.
Step 4. Identify water quality standards and criteria
Identify existing water quality standards and criteria applicable to the waterbodies and
stream segments being assessed. Water quality standards are laws or regulations adopted
by states and tribes to enhance water quality and to protect public health and welfare.
Water quality standards provide the foundation for accomplishing two of the principal
goals of the CWA: 1) to restore and maintain the chemical, physical, and biological
integrity of the nation's waters, and 2) where attainable, to achieve water quality that
promotes protection and propagation offish, shellfish, and wildlife and provides for
recreation in and on the water (EPA 1999).
A water quality standard consists of three elements: 1) the designated beneficial use or
uses of a waterbody or segment of a waterbody, 2) the water quality criteria necessary
to protect the use or uses of that particular waterbody, and 3) an antidegradation policy.
Water quality criteria describe the quality of water that will support a designated use and
may be expressed as either quantitative limits or a qualitative description. In practice,
criteria are set at levels that will protect the most sensitive of uses, such as human health
or aquatic life. An antidegradation policy ensures that water quality improvements are
conserved, maintained, and protected (EPA 1999).
Water quality criteria can be obtained from a wide range of sources:
• EPA criteria.
• State water quality criteria.
page
WQ-16 Water Quality
-------
• Site-specific criteria based on scientific studies.
• Agency guidelines.
Table 7 is an example of EPA water quality criteria. The term biota is fairly comprehensive,
so there may be scientifically justifiable reasons for requiring more or less stringent
criteria for a particular species than those shown in the table. Table 8 provides regional
reference values for natural water quality derived from 57 stations constituting the National
Hydrologic Benchmark Network.
Not all criteria have been translated into state or local laws; however, some agencies develop
policy based on criteria. A tribe or local health department, for example, may regulate
beach closures based on fecal coliform criteria without a specific water quality standard.
Table 7. EPA water quality criteria for DO concentrations (mg/L)
Cold water biota
Period
30-day mean
7-day mean
7-day minimum
1-day minimum
Early
9
8
Life
NA
6(6
NA
.0(5
* Applies to species that have early
Novotny and Olem
(1994)
Stages
5)*
•0)
Other Life Stages
6.5
NA
5.0
4.0
Warm water biota
Early Life Stages
NA
6.0
NA
5.0
Other Life Stages
5.5
NA
4.0
3.0
life stages exposed directly to water column.
Table 8. Regional reference values for regional natural water quality
Parameter
TSS (mg/L)
BOD (mg/L)
Nitrate (mg/L)
Total Phosphorus (mg/L)
Total coliforms (MPN/100 ml)
Novotny and Olem (1994)
Eastern
5-10
1.0
0.05-0.2
0.01-0.02
100-1000
Midwest
10-50
1-3
0.2-0.5
0.02-0.1
1000-2000
Region
Great Plains
20-100
2-3
0.2-0.5
0.1-0.2
500-2000
Mountain
5-20
1-2
0.1
0.05
100
Pacific
2-5
1
0.05-0.1
0.05-0.1
100-500
Water Quality
WQ-17
-------
Step 5. Identify indicators of impairment
Water quality impairment is typically defined as the exceedence of criteria, but other
indicators of problems, such as fish kills, algae blooms, and localized epidemics, should
also be examined. For each waterbody or stream segment, record potential indicators of
impairment on Form WQ1.
Numerous studies have been conducted to determine the precise combination of water
quality indicators necessary to accurately assess watershed conditions (EPA and USFWS
1984, Heaney 1989, Greeley-Polhemus Group 1991). Snodgrass et al. (1993) present a
sub-basin framework for managing environmental quality where flooding, erosion, surface
water quality, groundwater (quality and quantity), natural features (wetlands), aquatic
communities, recreation, aesthetics (water, valleyland), terrestrial (wildlife, woodlots), and
receiving waterbody issues are examined. Each category could be further divided to
coincide with the available data if additional clarification were needed. The EPA (1996a)
identified 18 environmental water quality indicators to meet five national environmental
goals. These indicators reflect the requirements of both the CWA and the Safe Drinking
Water Act. However, many of the indicators comprise multiple parameters whose relative
significance has yet to be established.
The EPA (1995a) used environmental indicators to judge the effectiveness of stormwater
management efforts. The indicators were selected from categories such as 1) water quality,
2) physical and hydrological, 3) biological, 4) whole watershed, 5) social, 6) programmatic,
and 7) site-specific compliance. Unfortunately, monitoring many of these indicators would
be cost-prohibitive.
Biological indicators have received considerable attention in recent years as potential
markers of watershed health. However, interpreting the results of bioassessment studies
can be difficult. Organism populations and community structures can vary considerably
according to season and site, making it difficult to interpret fluctuations.
Step 6. Analyze water quality data
Analyze the water quality data obtained in Step 1 and compare the data with the standards
and criteria identified in Step 2 to assess whether the existing water quality can support the
beneficial and cultural uses identified in Step 3- In some cases, evaluation of exceedences
may only require comparison of monitoring data to established standards and criteria. In
page
WQ-18 Water Quality
-------
more complicated watersheds, the assessment team might have to evaluate the quality of
the data, perform statistical analyses, or suggest possible standards or criteria. The major
tasks of this step are illustrated in Figure 2. The key questions listed in Box 2 will help
guide the Water Quality assessment team during the data analysis phase.
Figure 2.
Major tasks in water
quality data analysis
Prioritize waterbodies and
stream segments
T
Determine locations and
frequencies of exceedence
Compare water quality data
with reference conditions
Evaluate indicators of
water quality conditions
T
Summarize water
quality problems
Level 1 assessment involves basic statistical analyses
to describe the central tendency and spread of water
quality data. The mean or median describes the
central tendency of the sample, while the standard
deviation or interquartile range measures the spread
of data from the mean. Analysts can refer to several
documents for more detailed descriptions of statistical
procedures (Gilbert 1987, MacDonald et al. 1991,
EPA 1997a).
Prioritize waterbodies and stream segments
Decide which waterbodies or stream segments require
more detailed water quality evaluations. Contact
other members of the assessment team, such as the
Aquatic Life or Channel analyst to identify critical
areas. Reports that summarize water quality data and
concerns, such as the state 305(b) reports, can also
help to focus the assessment.
Aquatic Life
Channel
Box 2. Key questions for water quality data analysis
• In what sequence should the waterbodies be analyzed?
• How were the standards set up, (e.g., based on monthly or weekly mean concentration)?
• Is the water quality data format consistent with the standard?
• What water quality parameters have not met the standard and for how long?
• What beneficial uses are not supported in the waterbody?
• What are relevant background or reference conditions for the waterbodies of interest?
• How different is the existing water quality from the reference conditions?
Water Quality
WQ-19
-------
Determine locations and frequencies of exceedences
Review water quality data to identify exceedences of water quality criteria. Water quality
problems can also be identified by referencing water quality—related information such as
reports on fish kills, state 303 (d) reports, and other reported violations of water quality
standards.
Community
Resources
Historical
Conditions
The strength and rigor of the quality control should be considered in determining whether
or not the exceedence data are conclusive. EPA standards for monitoring should be
considered in reviewing the information (EPA 1996b). If monitoring data are inconclusive
or suspect because of quality control, care should be exercised in inferring water quality
problems.
Compare water quality data with reference conditions
Another approach for confirming water quality problems is to compare water quality
data to reference conditions, which represent the natural state prior to significant human
disturbance. Reference conditions can be identified in watershed areas with minimal
human influence. Another option is to use historical data to identify past reference
conditions. Data on reference conditions can be extremely valuable in the analysis process
to determine the degree of watershed deterioration and the feasibility of maintaining
certain beneficial uses. The reference condition approach is particularly useful when water
quality standards are not available.
Community
Resources
Aquatic Life
Evaluate indicators of water quality conditions
Using the information on indicators of water quality collected in Step 5, consider whether
water quality standards and criteria are sufficient to protect community resources. Identify
waterbodies where qualitative indicators such as fish kills, "swimmer's itch," unpleasant
odors, or fish consumption advisories suggest impairment of community resources.
Consult with the Community Resources analyst to help incorporate observations from the
local community.
Biological monitoring programs may provide useful information for identifying habitat
alterations, the cumulative effects of pollutants, and the biological integrity of aquatic
communities. A change in the abundance of organisms or in community composition
may indicate problems not revealed by more conventional water chemistry monitoring.
Consult with the Aquatic Life analyst about the status and trends of aquatic populations.
page
WQ-20
Water Quality
-------
Summarize water quality problems
Summarize the water quality problems in Form WQ1 and the Water Quality report.
The analysis of water quality exceedences, reference conditions, and impairment indicators
should provide the evidence to document water quality problems. Impaired stream
segments or other waterbodies should be highlighted on Map WQ1.
Water quality data may not be available or may have significant gaps for many of the
parameters. Major gaps in water quality data (e.g., inadequate coverage, infrequent
measurements, lack of reliability) should be identified in the Water Quality report.
Insufficient standards or criteria to evaluate water quality should also be highlighted.
Step 7. Identify potential pollution sources
Identify the potential sources of the water quality problems found in the watershed
information can be used as either a basis for further assessment or as a reference for
management plans. The general tasks involved in this step are illustrated
in Figure 3- Box 3 lists key questions that should be considered during
this step. Concluding that a waterbody is at risk from a particular practice
often requires explicit evaluation of the hazardous inputs, the transport of
pollutants, and delivery to sensitive resources in a Level 2 assessment.
Box 3. Key questions for pollution source identification
What are the potential sources of sediment, water, heat,
chemicals, pathogens, nutrients, etc.?
What is the fate of pollutants upon entry to the stream?
What is the potential for chemical change, dilution or other
transformation effects?
What is the potential for delivery via runoff, infiltration, or
atmospheric transport to sensitive segments?
What is the evidence for cause-and-effect linkages?
The
Figures.
Major tasks in pollution
source identification
Identify possible sources
T
Identify pathways of each
pollutant identified
Identity possible sources
Develop a list of all possible sources that relate to the water quality impairment, including
both point sources and non-point sources. A number of resources may be useful in this
part of assessment:
Water Quality
WQ-21
-------
• Resource Conservation and Recovery Act (RCRA) site data. Under the RCRA, the
EPA evaluates hazardous waste sites for corrective action. Information may be available
on toxic sources and risks to resources.
• NPDES permit data. State agencies are commonly responsible for implementation
of point source discharge permitting under the CWA. Under this authority, states
provide permits to pollutant dischargers based upon a review of receiving water
assimilation capacity, loading, and other considerations.
• Stormwater evaluations. County and city governments commonly conduct analyses
of stormwater and associated effects on water quality. This information may indicate
pollutant loadings of toxic and non-toxic substances.
• Health department studies and sanitary surveys. Health departments (state and
county level) commonly evaluate water quality impacts, including the impacts on
shellfish beds, groundwater, and surface water.
• State recreational studies. State recreation agencies commonly evaluate site qualities
with respect to human use potential, as well as the condition offish and wildlife
habitat.
• Species evaluations by the USFWS and state resource agencies. Habitat
conservation plans and other analyses evaluating habitat and impacting land practices
may be on file.
• Section 319 studies (under the CWA). These may include evaluations of water
quality problems, inventories, etc.
• Resource agency studies. Local, state, and federal agencies that regulate land
disturbing activities often have information on land use and potential water quality
problems. The NRCS commonly funds conservation districts to evaluate water quality
problems specific to agricultural lands. The BLM and USFS often have data on timber
sales, grazing allotments, and mining claims that may impact water quality.
Identify pathways of each pollutant identified
Identify the relationship between pollution sources and the water quality problems. A
pathway diagram is a useful tool to show the potential links between the source of
generation and water quality (Figures 4 - 8 in the "Level 2 Assessment" section). The
diagram is a simple way to crystallize the strategy for the assessment and narrow it down
to manageable dimensions.
page
WQ-22 Water Quality
-------
The identification of pathways should be based upon knowledge of pollutant-generating
activities, the transport of pollutants, and the location of water quality problems. The
Level 2 assessment provides more detailed information on identifying pollutant pathways.
Step 8. Produce Water Quality report
The Water Quality report should summarize water quality conditions, indicators of
impairment, and connections between pollutant sources and resource impairment.
Highlighting assumptions, gaps in data, and scientific uncertainty in the Water Quality
report will be important to evaluate the confidence in the assessment.
The report will typically include the following components:
• Summary of available water quality data.
• Applicable water quality standards and criteria.
• Community resources dependent on water quality.
• Exceedences of criteria and standards.
• Indicators of impairment.
• Potential sources of impairment.
• Conclusions of the assessment.
• Future monitoring and research needs.
• Confidence in the assessment.
Water Quality WQ-23
-------
Level 2 Assessment
This section provides a general overview of methods and tools that can be used in a Level 2
Water Quality assessment. It is not comprehensive and by no means represents a complete
procedure. Sources that provide more detailed information on assessment methods are
noted throughout this section.
Level 2 assessment can be complicated by the fact that water quality parameters are often
interrelated. Unlike more visible indicators of watershed health, water quality problems
often manifest themselves through symptoms that may occur miles downstream of the
actual problem. For example, eutrophication problems, caused by excessive phytoplankton
growth, require sufficient nutrients, temperature, light, and time. Problems with excessive
nutrient inputs upstream may not become evident until after water flows into a lake, where
sediments settle, allowing additional light penetration, the water temperature increases, and
the algae has time to grow. Investigating the lake for the source of nutrients may prove to
be futile because they were transported from upstream sources. This complexity may make
characterization or identification of water quality problems very difficult.
Level 2 assessment for water quality can be quite complicated and requires interaction with
several of the other module analysts, patricularly the Hydrology, Aquatic Life, and Erosion
analysts. Pathway analysis requires knowledge of water chemistry and environmental
science. Use of complicated mathematical models requires knowledge of both water quality
and computer modeling, and extensive training and experience may be necessary to use
computer simulation packages. In addition, Level 2 assessment may require extensive field
data collection at specific locations throughout the watershed. Thus, estimates of the time
and resources required for assessment need to take into account these elements.
This section focuses on methods and quantitative tools for estimating pollutant loading
from various sources. The methods and tools are divided into four categories:
• Analysis of mixing and dilution.
• Loading tables.
• Parameter-specific pathway analysis.
• Computer simulations.
page
WQ-24 Water Quality
-------
Analysis of Mixing and Dilution
A mixing and dilution calculation is the most widely used method for evaluating the
impact of a pollutant discharge on a receiving waterbody. The pollutant from a particular
source is typically diluted after being discharged. The impact of the discharge can be
evaluated by determining the pollutant concentration in the receiving waterbody after
mixing. Conversely, if an elevated pollutant concentration is measured and a source can
be identified, then the amount of discharge from the source can be back-calculated. The
equation used for these purposes is as follows:
Where: Cf = pollutant concentration after mixing.
Cj and C2 = pollutant concentrations in the source and the receiving
water before mixing, respectively.
Qj and Q2 = flow rates of the source and the receiving water,
respectively.
For a lake or a pond without appreciable water exchange, the mixing equation can be
written as follows:
Where: Vj and V2 = volumes of the source and the receiving water, respectively.
The resulting pollutant concentration assumes complete mixing of the pollutant and
the receiving waterbody. This generally will not occur until some distance downstream.
Within the initial dilution zone, concentrations may be considerably higher. The length
of the mixing zone can be quite variable depending on stream characteristics and
possible density or thermal stratification between the pollutant and the natural stream.
Several methods for determining the mixing zone length can be found in the literature.
These range from relatively simple rule-of-thumb approaches to computer models
such as CORMIX. Analytical solutions can be found for river mixing in references
such as Thomann and Mueller (1987) and Martin and McCutcheon (1999). Martin
and McCutcheon (1999) also present more in-depth theoretical discussions concerning
mixing in streams and lakes.
Water Quality WQ-25
-------
Loading Tables
Hydrology
When detailed information is not available or time and resources are not adequate to
do modeling, proper use of loading tables allows quick estimations of pollutants from a
particular source or land use. Loading tables give unit pollutant loading rates. Examples
include soil erosion per acre of land, atmospheric deposition per square foot of surface
area, and solids product rate per foot of curb length in cities. Table 9 illustrates some
approximate loading rates for different land uses in Washington State. Other sources
for unit loading values include McElroy et al. (1976), Thomann and Mueller (1987),
and Chandler (1993). Novotny and Chesters (1981) include approximations for nutrient
export based on geographic regions of the United States and land use. The values
are given in terms of concentration, so approximations for runoff must also be made
independently.
Table 9. Unit loads of pollutants (kg/ha/yr) from different land uses
Pollutant
TSS
COD
Pb
Zn
Cu
N03+N02-N
TKN
TP
* Exact values
siness
3
-Q
"s .«
*•• '»_
C *•
O V)
O T3
1080
1070
7.1
3.0
2.1
4.5
15
2.8
mercial
E
o
O
V
840
1020
3.0
3.3
n.a.
0.67
15
2.7
are given where
2.
"w
w
3
^
_c
56
63
0-7.1
3.5- 12
0.33-1.1
0.45
2.2- 15
0.
9-4.0
available;
V)
E
>S
"5>
c
-------
Parameter-Specific Pathway Analysis
Many equations or methods have been developed to analyze the relationship between
different forms or phases of pollutants. Pathway analysis explores the relationship
between different forms of a pollutant based on the physical or chemical processes
of transformation. Knowledge of these relationships will improve identification and
evaluation of pollutant sources. The pathway analysis conducted in a Level 1 assessment
(Step 7) is often qualitative, aiming at source identification. Pathway analysis conducted
in a Level 2 assessment is more quantitative, aiming at identification of the degree of
impact from one or more possible sources.
Temperature
The relationship between water temperature and the factors controlling it is well
understood and amenable to quantitative prediction. The temperature of a waterbody
can be determined by calculating the heat balance between the waterbody and the
surrounding environment. Major controlling factors include solar radiation, geographical
location, elevation, groundwater interaction, shading, and seasonal weather conditions
such as rain and wind.
Land use activities that affect discharge, streamside vegetation cover, and channel
morphology all exert variable influences on temperature in different climates. With other
factors held constant, streams with lower discharge are more susceptible to temperature
increases during the summer and decreases during the winter. Reduction of base flows also
causes increased seasonal temperature extremes because groundwater commonly warms
streams in winter and cools them in summer.
Hydrology
The reduction of stream surface shading by the removal of riparian vegetation can
significantly affect temperature, depending upon elevation, stream hydrology, and
groundwater/surface water interaction. Riparian grazing can also aggravate seasonal water
temperature extremes by reducing base flows via channel incision or soil compaction.
Restoration of riparian soils and vegetation through improved range management is one
of the most effective management tools available for increasing summer base flows.
Increases in channel width caused by high levels of sediment delivery or loss of bank
stability also exacerbate water temperature extremes in winter and summer. In summer,
Erosion
Water Quality
WQ-27
-------
Channel
Erosion
vegetation of a given height is less effective in shading wider channels. Wider and
shallower channels also have a greater heat load under a fixed energy budget because of
the increase in the stream surface area.
Temperature modeling can be conducted in two ways. The first deals with mixing of
water that has different temperatures, and the second is based on the heat balance of
a control waterbody. The mixing equation presented in the "Analysis of Mixing and
Dilution" section, can be used in temperature calculations by substituting temperature
(T) for concentration (C). This approach is generally used to estimate temperature
impacts from point sources. The heat balance approach, on the other hand, is used
widely in computer modeling for evaluating non-point sources. A good example can be
found in the QUAL2E user's guide (EPA 1995b).
Total suspended solids (TSS)
Erosion
The major sources of TSS include sediment, algae growth in the waterbodies, and point
source discharges. The sediment resulting from agricultural and urban runoff and from
streambanks can be estimated using methods provided in the Erosion module. TSS
caused by algae growth can be related to the nutrient concentration and productivity of
the waterbody. Direct discharge from point sources can be estimated from the NPDES
permit data, which are maintained by state agencies. TSS in a waterbody is additive;
the concentration of the TSS in a waterbody is the summation of the mass of TSS from
different sources divided by the volume of the waterbody. Some portion of the suspended
solids will settle.
Dissolved oxygen (DO)
The major DO sources include photosynthesis and reaeration (Figure 4). Cool
temperature, rapid aeration, and relatively low biochemical oxygen demand (BOD) may
increase DO. Respiration of photosynthetic organisms, decay of organic matter in the
water column, and benthic oxygen demand decrease DO. Introduction of organic matter
from both point and non-point sources to streams can increase BOD and decrease DO.
Photosynthetic contributions of oxygen occur only during daylight hours and are quite
seasonal. The primary contributors are algae. Highly eutrophic waters may range in DO
concentration from supersaturated during hot, sunny days to anaerobic at night.
page
WQ-28
Water Quality
-------
Figure 4. A simplified pathway of DO
Deoxygenation
due to BOD
In mountainous environments, streams possess little
vulnerability to low DO because fine organic debris
is generally sparse and reaeration of flowing water is
more than sufficient to maintain high levels of DO.
Low DO is more likely when the following conditions
are present:
• Very slow-moving, low-gradient, warm streams
with low discharge (i.e., low reaeration rates).
• Heavy inputs of fine organic debris to low-flow
streams, causing a large BOD or high
concentrations of organics.
• Warm, eutrophic streams, where high rates
of photosynthesis and respiration cause diurnal
fluctuations in DO (consuming oxygen without
reaeration). These conditions are similar to those
associated with lake eutrophication.
Large BOD is quite often localized to short reaches where organic material accumulates.
A second source of BOD demand is the growth of attached organisms, such as the
filamentous bacteria often released in wastewater discharges.
In general, risk determination should be based on high organic loading to slow moving
streams with limited reaeration potential. Streams subject to warming as a result of low
natural flow, water withdrawals, and loss of riparian shade are especially susceptible.
The saturation potential of oxygen depends on the water temperature, the atmospheric
pressure, and the salinity. For fresh water at sea level, the DO saturation concentration in
mg/L can be expressed as a function of temperature (American Public Health Association
1985):
Oxygen
generation by
photosynthesis
C =-139.34411 +
1.575701 E5
T
6.652308 E7
T2
1.2438 E10
T3
8.621949 Ell
T4
Where: T = temperature in degrees Kelvin (°C + 273-15).
GS = DO saturation (mg/L)
Water Quality
WQ-29
-------
Degradation of pollutants often reduces the DO concentration below the saturation
value. The oxidation of carbonaceous substances often causes reduced oxygen levels
downstream of point sources. Municipal waste increases BOD, so wastewater treatment
plants are a common starting point for this type of analysis. A common tool for
predicting DO concentrations under various flow conditions is the Streeter-Phelps
Equation. This equation is essentially a balance between DO consumption due to BOD
expression and stream reaeration. According to Thomann and Mueller (1987), the DO
balance equation can be written as follows:
{
K
d
K, - Kr
a
X X
exp(-Kr -- exp(-K
U U
L0 - (cs- c0 ) exp(-Ka
X
U
Where: Ka = reaeration coefficient.
Kj = effective deoxygenation rate.
Kr = BOD loss rate.
x = distance downstream of point source.
U = average water column velocity.
L0 = BOD concentration at the outfall.
c0 = DO concentration at the outfall.
cs = saturation concentration of oxygen.
pH modeling involves describing the hydrogen ion balance in water. The natural pH
balance of a waterbody can be affected by industrial effluents and atmospheric deposition
of acid-forming substances (i.e., acid rain). Changes in pH can indicate the presence of
certain effluents, particularly when continuously measured and recorded. Daily variations
in pH can be caused by photosynthesis and the respiration cycle of algae in eutrophic
water. The rapid growth of algae on a clear day can consume a significant amount of
carbon dioxide from the water and increase the pH. During the night, however, the
respiration of algae produces excessive carbon dioxide, which lowers the pH.
Nitrogen
In a natural environment, nitrogen undergoes biological and non-biological
transformations according to the nitrogen cycle (Figure 5). The major non-biological
page
WQ-30 Water Quality
-------
processes involve phase transformations such as volatilization, adsorption, and
sedimentation. The biological transformation involves the following:
1. Uptake of ammonia and nitrate by plants and micro-organisms to form organic
nitrogen.
2. Fixation of nitrogen gas by plants and bacteria to produce organic nitrogen.
3- Ammonification of organic nitrogen to produce ammonia during decomposition of
organic matter.
4. Oxidation of ammonia to nitrite and nitrate under aerobic conditions.
5. Bacterial reduction of nitrate to nitrous oxide and molecular nitrogen under
anaerobic conditions through denitrification.
Figure 5. Nitrogen cycle
Nondigestible
residue sink
nitrobacter
Animal
protein
Sawyer and McCarty (1978)
Plant
protein
Ammonia is highly soluble in water and occurs naturally in waterbodies from
the breakdown of nitrogenous organics. Discharges from industrial and municipal
wastewater treatment facilities are the most common non-natural sources of ammonia.
Ammonia can also result from atmospheric deposition.
Water Quality
WQ-31
-------
In aqueous solution, ammonia occurs in two forms, the un-ionized form (NH3) and the
ionized form (NH4). The un-ionized form of ammonia is toxic to aquatic life. The
ionized ammonia can be adsorbed onto colloidal particles, suspended sediments, and bed
sediments. Most reports refer to the concentration of total ammonia nitrogen, which is
the summation of the two forms:
NH3 + NH4 = Total Ammonia Nitrogen
The equilibrium between the two forms is determined by pH; the higher the pH,
the more un-ionized ammonia and the higher the toxicity. Unpolluted waters generally
contain a small amount of ammonia, usually < 0.1 mg/L as nitrogen. Total ammonia
concentrations measured in surface waters are typically less than 0.2 mg/L but may reach
2-3 mg/L. A higher concentration could be an indication of organic pollution such as
domestic sewage, industrial waste, or fertilizer runoff. Natural seasonal fluctuations also
occur as a result of the death and decay of aquatic organisms, particularly phytoplankton
and bacteria in nutritionally rich waters. High ammonia concentrations may also be
found in the bottom of lakes that have become anoxic.
Nitrate is an essential nutrient for aquatic plants, and seasonal fluctuations can be caused
by plant growth and decay. Under aerobic conditions, ammonia can be biologically
oxidized to nitrite and then to nitrate by a group of bacteria called nitrifiers.
Under anaerobic conditions with the presence of organic carbon, nitrate can also be
reduced to nitrite and then to nitrogen gas. As nitrite is an intermediate product,
nitrite concentration in natural waterbodies is usually quite low. Natural sources of
nitrate to surface water include igneous rocks and plant and animal debris. Natural
concentrations, which seldom exceed 0.1 mg/L, may be increased by municipal and
industrial wastewaters, including leachates from waste disposal sites and sanitary landfills.
In rural and suburban areas, the use of inorganic nitrate fertilizers can be a significant
source. Concentrations in excess of 5 mg/L usually indicate pollution by human and
animal waste or fertilizer runoff.
Nitrate is very mobile in soil because of its negative charge. The leaching of nitrate
to groundwater can cause groundwater impairments. Increasing groundwater nitrate
concentrations in many agricultural regions have been attributed to fertilizer application
and animal waste.
page
WQ-32 Water Quality
-------
Surface water impairments from nitrogen include eutrophication and toxicity from
nitrites, nitrates, and ammonia. Nitrites and ammonia are directly toxic to fish while
nitrates and phosphates affect fish indirectly. High nitrate and phosphate concentrations
are associated with stream eutrophication. Algae blooms and the profusion of other
aquatic plants may directly kill fish when vegetation dies and deoxygenation occurs.
Blooms and massive growth of other aquatic plants are possible when nitrate content in
the presence of other essential nutrients exceeds 0.5 mg/L.
Most nitrogen transformation processes are evaluated using computer models because of
the complexity of the nitrogen cycle caused by the many interactions. The computer
simulation models are summarized in a later section.
Phosphorus
Weathering of
phosphate rocks
Phosphate
fertilizer source
Natural sources of phosphorus are mainly derived from the weathering of
phosphorus-bearing rocks and the decomposition of organic matter. Domestic
wastewater (particularly wastewater containing detergents), industrial effluents, and
fertilizer runoff contribute
.... r Figure 6. Phosphorus cycle
to elevated levels in surface
waters. Major pathways of
phosphorus transformation
include plant uptake,
fertilization, and residue
decomposition (Figure 6).
Unlike nitrogen, phosphorus
is not particularly mobile
in soils, and phosphate ions
do not leach readily.
Phosphorus is held tightly
by a complex union with
clay and soil particulates
and organic matter. Most
phosphorus is removed from
soils either by crop uptake or
by soil erosion.
Removed from
cycle by harvesting
Leaching
Water Quality
WQ-33
-------
Phosphorus is rarely found in high concentrations in fresh water as it is actively uptaken
by plants. As a result, there can be considerable seasonal fluctuations in surface water
concentrations. In most natural surface waters, phosphorus concentrations range from
0.005 to 0.020 mg/L. Concentrations as high as 200 mg/L can be found in some
enclosed saline waters (Chapman 1996).
Most phosphorus-related water resource problems result from excessive annual loading.
However, if the water resource flushes seasonally, only the phosphorus loading
immediately preceding algae bloom periods may be of concern. For instance, runoff from
row cropland or suburban developments may be the major phosphorus loading source
on an annual basis, but these may be less important than wastewater treatment plant
contributions to algae bloom conditions during the summer and early fall.
Phytoplankton growth can be simulated using the following equation:
X
G = G
max
K + x
Where: G = growth rate based on nutrient limitation.
= temperature corrected maximum growth rate.
max
x = nutrient concentration.
Ks = half saturation constant for nutrient-limited growth.
Pathogens
Bacteria and viruses originate from runoff from livestock areas (Edwards et al. 1997),
bottom sediments (Sherer et al. 1988), wildlife (Weiskel et al. 1996), bacterial
populations resident in the soil (Crane et al. 1983), septic systems (Weiskel et al. 1996),
rural municipalities (Farrel-Poe et al. 1997), and runoff from urban areas (Schillinger
and Gannon 1985). Pathogens are largely carried to waterbodies by runoff or sediment
transport. Viruses depend heavily on adsorption to sediment particles, while bacteria
may be transported to waterbodies by various mechanisms, including infiltration, surface
runoff, and adsorption. Pathogens may enter separate storm sewers from leaking sanitary
sewers, cross-connections with sanitary sewers, malfunctioning septic tanks, and animal
wastes.
page
WQ-34 Water Quality
-------
Tools used in water quality assessment for pathogens are models for predicting pathogen
die-off and transport. Among the factors affecting survival of pathogens are pH, predation
by soil microfiora, temperature, presence of sediment, sunlight, and organic matter.
Tables 10 and 11 present information on some factors that impact pathogen survival.
Table 10. Factors that affect survival of enteric bacteria and viruses in soil
Factor
PH
Predation by soil microfiora
Moisture content
Temperature
Sunlight
Type of pathogen
Bacteria
Viruses
Bacteria
Viruses
Bacteria and viruses
Bacteria and viruses
Bacteria and viruses
Organic matter Bacteria and viruses
EPA (1977) and Novotny and Olem (1994)
Comments
Shorter survival in acidic soils (pH 3-5) than
in neutral and calcareous soils
Insufficient data
Increased survival in sterile soil
Insufficient data
Longer survival in moist soils and during
periods of higher rainfall
Longer survival at lower temperatures
Shorter survival at the soil surface
Longer survival or regrowth of bacteria when
sufficient amounts of organic matter are
present
Pesticides
The major sources of pesticides and insecticides
include agriculture, combined sewer outfalls,
urban runoff, and runoff from rural residential
areas. Insecticides include organochlorine,
organophosphorus, and carbamate chemicals.
Organochlorine compounds, such as DDT,
dieldrin, aldrin, heptachlor, and lindane can
persist in soils and aquatic environments for
many years (Figure 7). For example, DDT
has frequently been detected 10 years after its
application.
Table 11. Survival of selected pathogens in soils
Organism
Ascaris ova
Entamoeba histolytica cysts
Enteroviruses
Hookworm larvae
Salmonella
Salmonella typhi
Tubercle bacilli
Novotny and Olem (1994)
Survival time
(in days)
up to 7
6-8
8
42
15-100
1-200
More than 200
Water Quality
WQ-35
-------
Figure 7. Pathways for pesticide and organic compound transformation and transport
Water quality—related pesticide modeling includes calculations and simulations of
pesticide adsorption, decay, and transport. The oxygen status of soils and sediments has
a pronounced effect on the microbial breakdown of organochlorine pesticides. In soils
and sediments, DDT is rapidly converted to TDE (DDD) under anaerobic conditions.
Several organochlorine pesticides, including heptachlor, lindane, and endrin, have been
shown to degrade in soils to compounds of lower toxicity and reduced insecticidal activity.
Herbicides are less ubiquitous than are organochlorine insecticides. Such compounds as
s-triazines, picloram, monouron, and 2,4,5-T often persist in soils for as much as a year
following application.
Downward movement of agriculturally applied chemicals into soil layers and groundwater
is controlled by soil type, chemistry, pesticide composition, and climatic factors. The
leachability of a compound from soils depends primarily on the degree of adsorption of
the chemicals on soil particles. Models are also available to evaluate leaching potential
(i.e., downward mobility) of organic chemicals. Further information on models to
analyze pesticide movement are provided in the "Computer simulations" section.
Toxic metals and organic pollutants
Toxic metals and organic pollutants can be a serious water quality problem within
a watershed. While numerous sources exist for these pollutants (Table 12), most of
page
WQ-36
Water Quality
-------
Table 12. Sources of toxic metals and organic pollutants
Pollutants
Sources
Arsenic
Cadmium
Lead
Mercury
Benzene
Carbon tetrachloride
p-dichlorobenzene
1,1-dichloroethylene
1,1,1-trichloroethane
Trichloroethylene
Trihalomethanes
Natural geology, pesticide residue, industrial waste, smelting
Natural geology, mining, smelting
Lead pipes, lead-based solder
Air and water discharge from paint, paper, and vinyl chloride producers, natural geology
Petroleum fuel leaks, industrial chemical solvents, Pharmaceuticals, pesticides, paints, and plastics
Cleaning agents, industrial wastes from coolant manufacturers
Insecticides, moth balls, air deodorizers
Plastic, dye, perfume, and paint manufacturers
Food wrapping and synthetic fiber manufacturers
Pesticide, paint, wax and varnish, paint stripper, and metal degreaser producers, dry cleaning wastes
Surface water containing organic matter treated with chlorine
the toxic substances get into waterbodies and aquifers through point source discharges
and stormwater runoff. Modeling the fate and transport of these substances requires
knowledge of the chemical and physical characteristics of each particular substance
(Figures 7 and 8). Computer simulation software packages are available for such
applications.
Figure 8. Pathways for transformation and transport of heavy metals
Water Quality
WQ-37
-------
Computer Simulations
Mathematical models for water quality assessment should be selected based on their
intended uses and the conditions specific to the waterbody. A number of water
quality models have been developed for general uses. The complexity of these models
ranges from relatively simple spreadsheet-based pollutant loading models to extremely
intricate, three-dimensional, finite-element models. Historically, many models focused
on nutrients, DO, temperature, and BOD problems. Today, however, computer codes
capable of handling metals and dissolved constituents are also being introduced. Tables
13 and 14 summarize the main features of several existing watershed simulation models
that are generally available to the public. Detailed descriptions of these models can be
obtained from other sources (EPA 1997b, Deliman et al. 1999). Tables 13 and 14 are not
intended to be comprehensive and do not list models developed by private individuals or
companies. Many of these models are proprietary or extremely expensive to purchase.
All water quality models are approximations of mathematical or empirical relationships.
Consequently, it is very important that users understand the basic limitations or
constraints introduced by the approximations. A great deal of expertise in running and
interpreting model results is needed. Models can be shown to produce a widely varying
range of outputs depending on the selection of coefficients and other assumptions.
Proper calibration, validation, and sensitivity analysis require experience. The validity
of the results may be drawn into question by inexperienced modelers. Used properly,
models are powerful tools that can be used to help design water quality monitoring
programs and evaluate remediation scenarios. However, improperly used models will
ultimately lead to inconclusive or erroneous results and may cost more time and resources
than they save.
page
WQ-38 Water Quality
-------
Table 13. Capabilities of water quality models
Attributes
Models
AGNPS
ANSWERS
BATHTUB
CE-QUAL-RIV1
CE-QUAL-W2
CE-QUAL-ICM
CH3D-WES
CREAMS
DELFT3D
DYNTOX
EFDC
EUTROMOD
EXAMSII
HSPF
PRZM
QUAL2E
SWRRB
SMPTOX
TPM
UTM-TOX
WASPS
WEPP
H = High
L= Low
M = Medium
EPA (1997b)
Source
USDA
Purdue
USAGE
USAGE
USAGE
USAGE
USAGE
USDA
DELFT
EPA
Tetra Tech
NALMS
EPA
EPA
EPA
EPA
USDA
EPA
William & Mary
ORNL
EPA
USDA
N = No
Y=Yes
Temperature
N
N
Y
Y
Y
Y
Y
Y
N
Y
N
Y
N
Nutrients
Y
Y
Y
Y
Y
Y
N
Y
Y
N
Y
Y
N
Y
Y
N
Y
N
Y
en
ro
N
N
N
N
N
Y
N
Y
N
N
N
Y
Y
Y
Pesticides
Y
N
N
N
N
Y
N
Y
Y
N
N
Y
Y
N
Y
Y
N
N
O)
Erosion Modelin
Y
Y
N
N
N
N
N
Y
N
N
N
Y
Y
N
Y
N
N
Y
N
Y
„ Range of applications
ro .y
||
CO ^
CO 0
D
D
SS
D
D
D
D
D
D
D
SS
SS
D
SS
SS
SS
D
In-stream Water
Quality
Simulation
N
N
Y
Y
Y
Y
N
Y
Y
Y
N
Y
N
Y
Y
N
Y
Screening
H
H
L
-
L
L
H
L
H
H
L
H
M
H
H
L
Intermediate
M
H
H
M
M
M
L
M
M
H
M
H
H
M
H
H
T3
_CD
'5
Q
-
H
H
H
H
H
-
H
-
-
H
M
H
M
M
L
Management
M
H
H
H
M
H
L
M
M
M
H
H
M
H
H
H
Water Quality
WQ-39
-------
Table 14. Overview of water quality models
Watershed-scale loading models
Simple methods
EPA Screening
Simple Method
Regression Method
SLOSS-PHOSPH
Watershed
FHA Model
Watershed Management Model
Field-scale loading methods
CREAM/GLEAMS
Opus
WEPP
Receiving water models
Mid-range methods
SITEMAP
GWLF
Urban Catchment Model
Automated Q-llludas
AGNPS
SLAMM
Integrated modeling systems
PC-VIRGIS
WSTT
LWMM
GISPLM
BASINS
Detailed models
STORM
ANSWERS
DR3M-QUAL
SWRRMWQ
SWMM
HSPF
Hydrodynamic
RIVMOD-H
DYNHYD5
EFDC
CH3D-WES
Steady-state water quality Dynamic water quality Mixing zone models
EPA Screening
EUTROMOD
PHOSMOD
BATHTUB
QUAL2E
EXAMS II
TOXMOD
SMPTOX3
Tidal Prism Model
DECAL
DYNTOX
WASPS
CE-QUAL-RIVI
CE-QUAL-W2
CE-QUAL-ICM
HSPF
CORMIX
PLUME
EPA (1997b)
page
WQ-40
Water Quality
-------
References
American Public Health Association. 1985- Standard methods for the examination
of water and waste water, 16th edition. American Public Health Association,
Washington, D.C.
Buffo, J. 1979- Water pollution control early warning system. Section 1, Non-point
source loading estimates. Municipality of Metropolitan Seattle (METRO),
Washington.
Chandler, R. D. 1993- Modeling and nonpoint source pollution loading estimates in
surface water management. Thesis, M.S.E., University of Washington, Seattle.
Chapman, D. 1996. Water quality assessments: A guide to the use of biota, sediments,
and water in environmental monitoring. E & FN Spon., New York, New York.
Crane, S. R., J. A. Moore, M. E. Grismer, and J. R. Miner. 1983- Bacterial pollution from
agricultural sources: A review. Trans. ASAE 26:858-866, 872.
Deliman, P. N., R. H. Click, and C. E. Ruiz. 1999- Review of watershed water
quality models. U.S. Army Corps of Engineers, Waterways Experiment Station,
Technical Report W-99-1, Vicksburg, Mississippi.
Edwards, D. R., B. T Larson, and T T Lim. 1997- Nutrient and bacteria content
of runoff from simulated grazed pasture. Presented at the 1997 ASAE Annual
Meeting, Paper No. 97-2055, St. Joseph, Michigan.
Farrell-Poe, K. L., A. Y Ranjha, and S. Ramalingam. 1997- Bacterial contributions by
rural municipalities in agricultural watersheds. Trans. ASAE 40(1):97-101.
Gilbert, R. O. Statistical methods for environmental pollution monitoring. Van Nostrand
Reinhold, New York, New York.
Greeley-Polhemus Group. 1991. Economic and environmental considerations for
incremental cost analysis in mitigation planning. U.S. Army Corps of Engineers,
Institute for Water Resources, IWR Report 91-R-l, Washington, D.C.
Water Quality WQ-41
-------
Heaney, J. P. 1989- Cost effectiveness and urban storm-water quality criteria. In: L.
Roesner, B. Urbonas, and M. Sonnen (eds.). Design of urban runoff quality
controls. ASCE, New York, New York.
Homer, R., B. W Mar, L. E. Reinelt, J. S.. Richey, and J. M. Lee. 1986. Design
of monitoring programs for determination of ecological change resulting from
nonpoint source water pollution in Washington State. University of Washington,
Department of Civil Engineering, Seattle, Washington.
MacDonald, L. H., A. W Smart, and R. C. Wissmar. 1991- Monitoring guidelines to
evaluate effects of forestry activities on streams in the Pacific Northwest and
Alaska. U.S. Environmental Protection Agency, EPA-910/9-91-001, Washington,
D.C.
Martin, J. L., and S. C. McCutcheon. 1999- Hydrodynamics and transport for water
quality modeling. Lewis Publishers, Boca Raton, Florida.
McElroy, A. D., S. Y Chiu, J. W. Nebgen, A. Aleti, and E W. Bennett. 1976.
Loading functions for assessment of water pollution from nonpoint sources.
U.S. Environmental Protection Agency, Midwest Research Institute, EPA-600/2-
76-151, Kansas City, Missouri.
Novotny, V., and G. Chesters. 1981. Handbook of nonpoint pollution. Van Nostrand
Reinhold, New York, New York.
Novotny, V., and H. Olem. 1994. Water quality: Prevention, identification, and
management of diffuse pollution. Van Nostrand Reinhold, New York, New York.
Puget Sound Water Quality Authority. 1986. Nonpoint source pollution. Puget Sound
Water Quality Authority, Seattle, Washington.
Regional Interagency Executive Committee (RIEC) and Intergovernmental Advisory
Committee (IAC). 1995- Ecosystem analysis at the watershed scale: federal
guide for watershed analysis, version 2.2. Regional Ecosystem Office, Portland,
Oregon.
page
WQ-42 Water Quality
-------
Sawyer, C. N., and P. L. McCarty. 1978. Chemistry for environmental engineering.
McGraw-Hill Book Company, New York, New York.
Schillinger, J. E., and J. J. Gannon. 1985- Bacterial adsorption and suspended particles
in urban stormwater. Journal of the Water Pollution Control Federation
57(5):384-389.
Sherer, B. M., J. R. Miner, J. A. Moore, and J. C. Buckhouse. 1988. Resuspending
organisms from a rangeland stream bottom. Trans. ASAE 31(4):1217-1222.
Snodgrass, W., D. E. Maunder, K. Schiefer, and K. C. Whistler. 1993- Tools for
evaluating environmental quality, water quality and water quantity issues. In: W.
James (ed.). New techniques for modeling the management of stormwater quality
impacts. Lewis Publishers, Boca Raton, Florida.
Thomann, R. V., and J. A. Mueller. 1987- Principles of surface water quality modeling
and control. Harper & Row, New York, New York.
U.S. Environmental Protection Agency (EPA). 1977- Stanley W. Zison. Water quality
assessment: A screening method for nondesignated 208 areas. EPA, EPA-600/6-
77/023, Washington, D.C.
U.S. Environmental Protection Agency (EPA). 1994. Water quality handbook. EPA,
Office of Water, EPA-823-B-94-005a, Washington, D.C.
U.S. Environmental Protection Agency (EPA). 1995a. Environmental indicators to assess
the effectiveness of municipal and industrial stormwater control programs. Draft.
EPA, Office of Wastewater Management, Washington, D.C.
U.S. Environmental Protection Agency (EPA). 1995b. QUAL2E Windows interface
user's guide. EPA, Office of Water, EPA-823-B-95-003, Washington, D.C.
U.S. Environmental Protection Agency (EPA). 1996a. Environmental indicators of water
quality in the United States. EPA, Office of Water, EPA-841-R-96-002, EPA,
Washington, D.C.
Water Quality WQ-43
-------
U.S. Environmental Protection Agency (EPA). 1996b. The volunteer monitor's guide to
quality assurance project plans. EPA, EPA-84l-B-96-003m, Washington, D.C.
U.S. Environmental Protection Agency (EPA). 1997a. Monitoring guidance for
determining the effectiveness of nonpoint source control. EPA, Office of Water,
EPA-841-B-96-004, Washington, D.C.
U.S. Environmental Protection Agency (EPA). 1997b. Compendium of tools for
watershed assessment andTMDL development. EPA, EPA-841-B-97-006,
Washington, D.C.
U.S. Environmental Protection Agency (EPA). 1999- Introduction to water quality
standards. EPA, Office of Water, EPA-823-F-99-020, Washington, D.C.
U.S. Environmental Protection Agency (EPA) and U.S. Fish and Wildlife Service
(USFWS). 1984. 1982 national fisheries survey. EPA and USFWS, Washington,
D.C.
Weiskel, P. K., B. L. Howes, and G. R. Heufelder. 1996. Coliform contamination of
a coastal embayment: sources and transport pathways. Environ. Sci. Technol.
30:1872-1881.
page
WQ-44 Water Quality
-------
Form WQ1. Summary of water quality conditions
Sub-basin
Waterbody
Segment
Beneficial
uses
Parameters of
concern
Indicators of
impairment
Notes (data sources,
land use hazards)
Water Qual
WQ-45
-------
page
WQ-46
Water Quality
-------
Historical Conditions
-------
Background and Objectives
Understanding the history and location of natural disturbances (e.g., fires and droughts)
and human disturbances (e.g., dam construction and human settlement patterns)
provides valuable information about past and current conditions of the watershed. The
Historical Conditions module summarizes information on past watershed disturbances
and on watershed conditions prior to disturbance.
The Level 1 approach relies on existing documents (e.g., maps, surveys, tribal documents,
and research papers) as the primary source of historical information. The increased
assessment time in the Level 2 approach allows for a more in-depth assessment of
historical information or personal interviews with tribal elders and community members.
Both the Level 1 and Level 2 approaches summarize the collected information in a
timeline, a map, and a historical narrative.
Historical
Conditions
HC-1
-------
Historical Conditions Module Reference Table
Critical Questions
HC1:
What land use/management
changes have occurred within
the watershed since European
settlement?
HC2:
What are the natural setting
and disturbance regimes in the
watershed?
HC3:
Where and when have land-
scape changes occurred in the
watershed?
Information
Requirements
• Historical watershed
information:
- Land surveys
— Settlement patterns
— Tribal documents
— State and federal reports
• Historical watershed
information:
— Land surveys
— Vegetation surveys
— Climate data
- Fire records
• Anecdotal information
• Historical watershed
information:
— Land surveys
- Vegetation surveys
- Fire records
Level 1
Methods/Tools
• Collect and summarize existing
information
• Collect and summarize existing
information
• Collect and summarize existing
information
Level 2
Methods/Tools
• Develop survey/questionnaire
• Conduct interviews
• Develop survey/questionnaire
• Conduct interviews
• Conduct interviews
page
HC-2
Historical
Conditions
-------
Level 1 Assessment
Step Chart
Data Requirements
• Historical watershed information
• Topographic map of watershed
• Aerial photos
Products
Form HC1. Historical timeline
Form HC2. Trends in watershed resource conditions
Map HC1. Historical sites
Historical Conditions report
Produce Historical Conditions report
Procedure
The objectives of the Historical Conditions module are as
follows:
• To collect historical documents on the settlement and use of
the watershed.
• To identify past human and natural disturbances in the
watershed.
• To provide a historical context for the use and alteration of
watershed resources.
Step 1. Collect historical watershed information
The first step is to decide where to look for historical
watershed information. Box 1 lists possible sources, and Box 2
lists places to start looking for documents on the history of the
watershed. Consult the tribal council, tribal elders, and other
Box 1. Sources of historical information
• Old books and maps
- Explorers diaries and sketches
- Historical accounts
• Public land surveys
• Tribal treaties and other documents
• Tribal elders
• Landscape photographs
• Aerial photographs
• City plans
• Local and state history books
• Newspaper accounts
• Scientific journals
• Published oral histories
Historical
Conditions
HC-3
-------
Community
Resources
Aquatic Life
Vegetation
Hydrology
Channel
long-time community residents for
valuable anecdotal information
about watershed conditions and
uses. Also, consult with the
Community Resources, Aquatic
Life, Vegetation, Hydrology, and
Channel analysts to share
information.
Box 2. Locations of historical information
Tribal archives
Historical museums
City archives
Local libraries
State, county, and federal agencies
Universities and tribal colleges
Local historical societies
The analyst should gather
information about historical development and changes to the landscape (e.g., dam
construction, irrigation, settlement patterns, land use). It is also helpful to get
information about climatic events and large natural disturbances (e.g., floods, hurricanes,
fires, droughts, windstorms, earthquakes, insect outbreaks).
Step 2. Summarize historical conditions
Identify major historical events on timeline
An effective way to summarize historical events is in a timeline format. Figure 1
illustrates a general timeline approach. The detail of the timeline will vary depending
on the amount of historical
Figure 1. Sample Form HC1. Historical timeline documentation available and
the size of the watershed. It
may be possible to extrapolate
regional information to make
assumptions about historical
land use and disturbance.
Organizing the information
as a timeline enables readers
to quickly understand the
timing of important events
that have affected watershed
conditions. Whatever format
is used for the timeline, label
it Form HC1.
Date
1850s
1890s
1890s-1930s
1910
1925
1930
1940
1950-1970
1980
Historical Event
First eastern brook and rainbow trout stocked in Kootenai
Early attempts at dike construction
Channel alteration from log drives in tributaries
Wildfires
Lake Creek Dam in operation
Moyie Dam in operation
Sturgeon declines, commercial fishing stopped
Cominco Fertilizer Plant
Non-selective kill from gas bubble disease, 1 7 miles from dam
Adapted from Sasich etal. (1999)
page
HC-4
Historical
Conditions
-------
Summarize trends in resource conditions
From the information presented in the timeline, trends in resource conditions may
be identified, and connections between land use practices and resource trends can be
hypothesized. From the Kootenai timeline (Figure 1), trends in resource conditions can
be connected to specific land use practices, such as dike construction, log drives, and dam
operation. Information on watershed changes can be listed in Form HC2 (Figure 2).
Consult with the Community Resources, Aquatic Life, and Water Quality analysts for a
complete list of resources.
Figure 2. Sample Form HC2. Trends in watershed resource conditions
Resource
Sturgeon
Wetland habitat
Water quality
Trend
• Declining numbers found
in Kootenai and tributaries
• Decreasing numbers of wetlands
• Higher quantities of chemicals
in water
Disturbance
• Channel alteration
• Impacts from dams
• Dike construction
• Dam operations
• Industrial effluent
• Mines
Adapted from Sasich et al, (1999)
Write watershed historical narrative
The watershed historical narrative pulls together the information collected on historical
watershed conditions and natural and human disturbances. Beginning from the earliest
information available, tie together the history of water quality, aquatic life, land use
impacts, channel alterations, and settlement patterns. A sample watershed historical
narrative is provided in Box 3-
Map historical sites and landscape disturbances
Once the historical information is summarized, it may be useful to map the locations
of historical sites and disturbances (Map HC1). If the watershed is large, break it into
sub-basins to get a finer resolution.
Community
Resources
Aquatic Life
Water Quality
Historical
Conditions
HC-5
-------
Box 3. Watershed historical narrative from Quinault Watershed Analysis
The Upper Quinault River Valley remained geographically isolated until exploration by the Gillman
Expedition in 1889. The first Euroamerican settlers arrived in the Cook/Elk and Quinault Lake [areas] in
1889, and practiced subsistence farming and grazing. By 1897, homesteaders had occupied most of the
suitable bottom lands around Lake Quinault and as far upstream as the confluence of the North and East
Forks of the Quinault River. Present day settlement is concentrated in the Neilton and Amanda park areas
near Quinault Lake and in the unincorporated village of Taholah, located at the mouth of the Quinault River.
Timber harvesting, fishing and tourism have been the prominent economic influences in the Quinault River
watershed. Logging began in 1916, when cedar was salvaged from the "Neilton Burn". By 1924 the advent
of railroad logging made large-scale commercial timber harvesting viable in the Cook/Elk and Quinault
River [areas]. Extensive road construction and subsequent timber harvesting occurred between 1950 and
1980. Although the level of old growth harvesting has declined in recent years, second growth forest
management and related forestry activities such as cedar salvage and gathering of special forest products
will continue to play an important role in the local and regional economy.
Quinault Indian Nation (1999)
Types of information to be placed on Map HC1 include the following:
• Dams and diversions.
• Water quality impacts (e.g., toxic spill, algal bloom).
• Channel modifications (e.g., dikes, channel straightening).
• Historical fishing sites.
• Historical wetlands and floodplains.
• Historical sites.
• Fires.
Step 3. Produce Historical Conditions report
The Historical Conditions report should include the watershed historical narrative, the
map of historical sites (Map HC1), and the forms showing a historical timeline and
resource trends (Forms HC1 and HC2). A possible outline for the report is provided
in Box 4.
page
HC-6
Historical
Conditions
-------
Box 4. Sample outline for Historical Conditions report
A. Historical Watershed Narrative
1. Watershed resources at time of European settlement
a. Native American use
b. Vegetation
c. Presence and abundance offish and wildlife species
d. Stream habitat
e. Natural disturbance patterns
2. Historical settlement, land use, and resource management patterns
a. Settlement patterns and development: rural and urban
b. Roads
c. Dikes
d. Logging practices
e. Agriculture
f. Urbanization
g. Grazing
h. Mining
i. Water use, diversions
j. Fisheries exploitation
k. Changes in disturbance patterns
B. Summaries of Historical Conditions
1. Form HC1. Historical timeline
2. Form HC2. Trends in watershed resource conditions
3. Map HC1. Historical sites
C. Conclusions
1. Summary of watershed conditions and change
2. Conclusions about historical conditions that are currently
impacting community resources
D. Sources of information
Adapted from Watershed Professionals Network (1999)
Historical
Conditions
HC-7
-------
Level 2 Assessment
The Level 2 assessment is similar to the Level 1 assessment, but more time and resources
may allow for more extensive information collecting activities, such as the following:
• Sending out a questionnaire to community members.
• Conducting personal interviews.
• Working with a local historian or university anthropology department.
page
HC-8
Historical
Conditions
-------
References
Quinault Indian Nation. 1999- Quinault Watershed Analysis. Quinault Indian Nation,
Taholah, Washington.
Sasich, ]., E Olsen, and J. Smith. 1999- Kootenai River watershed assessment. Final
report prepared for the Kootenai Tribe of Idaho.
Watershed Professionals Network. 1999- Oregon watershed assessment of aquatic
resources manual. Draft report prepared for the Governors Watershed
Enhancement Board, Salem, Oregon.
Historical
Conditions
HC-9
-------
Form HC1. Historical timeline
Date
Historical Event
page
HC-10
Historical
Conditions
-------
Form HC2. Trends in watershed resource conditions
Resource
Trend
Disturbance
Historical
Conditions
HC-11
-------
page
HC-12
Historical
Conditions
-------
Hydrology
-------
Background and Objectives
The purpose of the Hydrology module is to characterize the hydrologic regime of the
•watershed and assess its susceptibility to alterations from land and •water use practices.
When hydrologic processes are altered, the stream system responds by changing physical
parameters, such as channel configuration. These changes may in turn impact chemical
parameters and ultimately the aquatic ecosystem.
The degree to •which hydrologic processes are affected by land and •water use depends
on the location, extent, timing, and type of activity. Watershed activities can potentially
cause changes in the magnitude and timing of both peak flows and low flows. Some
activities (e.g., temporary roads, low levels of timber harvest, and seasonal irrigation
withdrawals) cause short-lived alterations to the hydrologic regime, •while other activities
(e.g., dams, urbanization, and channelization) cause fairly permanent changes in the
•watershed and thus to the hydrologic regime.
Hydrologic processes are complex, involving myriad interactions that are difficult to
quantify. The list of hydrologic concerns generated in the Scoping process •will provide
direction to the assessment. In addition, seven critical questions are posed to help focus
the assessment. The Hydrology Module Reference Table indicates the critical questions
that may be addressed in the initial Level 1 assessment and options for further Level 2
analyses. This module provides detailed steps for Level 1 assessment and a general
discussion of options for Level 2 assessment.
Level 1 assessment characterizes the hydrology and climate of the •watershed and screens
for potential land and •water use impacts. Characterization refers to gathering and
organizing existing data into a qualitative description of conditions. The Level 1
assessment does not produce definitive or quantitative results; however, the screening does
provide justification and focus for future Level 2 assessment.
page
Hydrology HY-1
-------
Hydrology Module Reference Table
Critical Questions
Information
Requirements
Level 1
Methods/Tools
Level 2
Methods/Tools
H1:
What Is the seasonal variabil-
ity in streamflow?
H2:
What is the climatic setting of
the watershed?
H3:
What are the roles of ground-
water and natural storage fea-
tures in the watershed?
H4:
What are the active runoff
generating processes?
H5:
What water control structures
are present in the watershed?
H6:
For which beneficial uses is
water primarily used in the
watershed, and are surface
water or groundwater with-
drawals prominent?
H7:
What are the potential land
use impacts to hydrologic
processes in the watershed?
* Representative streamflow
records
• Representative climate data
* Topographic maps
* Watershed characteristics
• Hydrogeologic maps and aqui-
fer descriptions
• Vegetation module maps
* Topographic maps
• Watershed characteristics
* Historical Conditions module
timeline
* Aerial photos
• Topographic maps
* Land use map
* Topographic maps
* Aerial photos
* Percentage of watershed occu-
pied by each land use
• Vegetation coverage
• Hydrologic soil information
• Percentage impervious area
* Tabulate and graph flow data
* Summarize peak and low flow
patterns
• Tabulate and graph precipitation
data
* Summarize storm patterns
• Locate storage features in the
watershed: snowpack, lakes, wet-
lands/swamps
* Define groundwater areas
* Describe runoff processes
* Locate reservoirs, lakes, diver-
sions, dams
* Characterize extent of draining
and ditching and other hydro-
modifications
* Identify types of water uses and
typical withdrawals in the water-
shed
• Determine periods of high water
demand
* Screen for potential impacts
* Ungaged streamflow analysis
* Frequency analysis (flood and
low flow)
• Flow duration curves
• Storm analysis
* Trend analysis
* Double mass analysis
• Hydrograph separation
techniques
• Characterize surficial aquifers
* Storm analysis
• Watershed hydrologic models
* Deregulate streamflow records
* Reservoir routing models
* Reservoir operation models
• Watershed hydrologic models
* Water rights analysis
* Consumptive use estimates
* Water balance calculations
• Network/allocation models
• 3D groundwater models
* Empirical relationships
* Regional relationships and
models
• Storm hydrograph techniques
• Continuous hydrologic models
page
HY-2
Hydrology
-------
Level 1 Assessment
Step Chart
Data Requirements
Summarize the role of groundwater and
other natural storage features
• Map of the watershed showing topography
and stream network. USGS or equivalent
topographic quadrangle maps at a
1:24,000 scale are adequate.
• Stream network classification map (if
available). Many states have adopted
regulatory categorizations pertinent to
stream order (e.g., stream order, water
type, stream class). If state classification
maps are available, they can be useful to
cross-reference with the Channel module
and Aquatic Life module analysts.
• Land use map with sub-basins delineated
(from Scoping).
• Mean annual precipitation map.
• USGS hydrologic atlases and groundwater
atlases.
• Streamflow data.
• Soil survey maps.
• Surficial geology maps (if available).
• Hydrogeologic maps describing aquifer
conditions (if available).
• Aerial photos or orthophotos (as necessary).
• Other relevant published or unpublished documents (city, county, tribal, state, or
federal agency or private consultant reports) with watershed information.
Data Sources
Section 1
Characterize the
Hydrology and Climate
Section 2
Screen for Potential Land and
Water Use Impacts on Hydrology
Identify general watershed characteristics
Screen for potential agriculture
or rangeland issues
Screen for potential urban, suburban,
or rural residential issues
The USGS is the best source of water-related information in the United States. The
USGS collects Streamflow, surface water quality, groundwater level, and groundwater
Hydrology
page
HY-3
-------
quality data. It publishes water resources data by state and water year, water resources
investigation reports, open-file reports, water resources bulletins, professional papers,
and hydrologic investigations atlases. USGS publications are available in many libraries
or they can be ordered through the U.S. Government Printing Office. The information
number for the USGS is 1-800-426-9000.
Hydrologic data
Current and historical streamflow data can be downloaded from the home pages of the
USGS district water resource offices. Streamflow data are also available commercially on
CD-ROM. Published resources include the following:
• USGS. National Water Summaries: Hydrologic Events and Surface- Water Resources.
These documents contain nationwide and state information on water resources,
including generalized maps of surface water runoff, water-related issues, groundwater
quantity and quality, and wetland locations.
• U.S. Water Resources Council (1978). The Nations Water Resources. Although dated,
this is still the most recent and comprehensive nationwide assessment of the United
States' water problems.
• USGS publishes open file reports containing regional flood equations (e.g., USGS
1979).
Climatic data
The National Weather Service and its data repository, the National Climate Data
Center, have websites that provide easy access to useful climate information (http://
www.nws.noaa.gov and http://www.ncdc.noaa.gov). Climate data are also available
commercially on CD-ROM. There are six regional climate centers (Western Regional,
High Plains, Southern, Midwestern, Southeast, and Northeast), each of which
can provide information on how and where to download climate data and assist
in identifying an appropriate climate station. Some states have designated state
climatologists who are a valuable resource. Published resources include the following:
• NOAA National Weather Service. The Climatic Record of the United States by
State. These documents contain daily, monthly, and annual climate information
on precipitation, temperature, evaporation, degree days, and other climate data by
weather station. NOAA also publishes a Mean Annual Precipitation Map.
page
HY-4 Hydrology
-------
• U.S. Weather Bureau Technical Paper 40, Rainfall Frequency Atlas of the United
States provides information on 24-hour storms for the conterminous United States.
Precipitation atlases for specific states (e.g., Miller et al. 1973) are also available.
Water use data
The USGS updates water use estimates every five years. Water use data can be obtained
through the USGS water use icon on the EPA's Surf Your Watershed web site (http://
www.epa.gov/surf/).
Groundwater resources data
• Hydrogeologic provinces. Heath (1984).
• The Ground Water Atlas of the United States, USGS Hydrologic Investigations Atlas,
HA 730 A-N series. This atlas consists of 14 chapters that describe the groundwater
resources of regional areas. A nationwide aquifer map is included along with
descriptions of groundwater characteristics, flow directions, chemical composition, and
water balance components such as runoff, precipitation, and evaporation. The text of
this atlas is available online (http://wwwcapp.er.usgs.gov/publicsdocs/gwa).
Products
• Form HI. General watershed characteristics
• Form H2. Summary of hydrologic issues by sub-basin
• Map HI. Water control structures
• Hydrology report
Procedure
The primary objectives of the Hydrology assessment are as follows:
• To characterize the hydrologic regime of the watershed by summarizing the following:
— Watershed characteristics.
— Streamflow patterns.
— Precipitation patterns.
— Watershed storage and groundwater features.
— Watershed runoff processes.
page
Hydrology HY-5
-------
• To locate land uses (agriculture and rangeland, urban, forestry, mining, etc.), water
uses, and water control structures (dams, dikes, diversion, etc.) in the watershed.
• To screen for potential impacts on hydrology from land and water use.
The Level 1 evaluation procedure is separated into two sections. The steps in Section 1
characterize the hydrologic and climatic setting of the watershed. The steps in Section 2
direct the user to screen for potential hydrologic issues associated with the land and water
uses present in the watershed.
The hydrologic evaluation may need to be carried out at the sub-basin level. This
will require adjusting streamflow and precipitation records to reflect conditions in each
sub-basin.
Section 1. Characterize the Hydrology and Climate
The geographic layout of the United States encompasses several diverse physiographic and
climatic zones, causing the amount of runoff and its distribution throughout the year to
vary considerably from region to region (Figure 1). Watersheds differ in both the ability
to produce flood flows and the ability to sustain flows during the dry periods.
Most streams do not produce uniform flow over the year. Instead, streams typically
exhibit patterns in flow reflective of individual storms, months, and seasons (Figure 1).
The seasonal pattern of streamflow in a watershed is largely governed by the climatic
inputs to that watershed (the amount, form, and timing of precipitation) offset by
losses from the watershed (the amount and timing of evapotranspiration losses and
snowmelt). The geologic characteristics of the watershed also heavily influence the
streamflow regime, as demonstrated by the marked difference between the hydrographs
compared in Figure 2. (A graphical plot of streamflow data over time is called a
hydrograph.) Finally, physical characteristics—such as the size of a river system, drainage
shape, topography, type of vegetation or ground cover, and amount of natural water
storage—all influence the specific runoff pattern of a given stream.
While flooding is common in each of the 50 states, the type and frequency of peak flow
events differ dramatically both within and among states. Floods can stem from many
factors, including heavy rainfall, rapid snowmelt, rain-on-snow, and thunderstorms, as
well as more dramatic ice jam breakups, channel avulsions, and dam or levee failures.
In coastal areas, hurricanes, winter storms, tsunamis, and rising sea levels can generate
floods.
page
HY-6 Hydrology
-------
Figure 1. Average monthly runoff (as a percentage of annual flow) for selected gages in the United States
Adapted from Satterlund and Adams (1992)
Baseflows or low flow regimes also vary from stream to stream. Intermittent streams
go dry for a period of time every year, while other streams do not experience much
fluctuation from high flow to low flow periods (see example for Yadkin, South Carolina,
in Figure 1). Many factors influence the amount of water found in streams during the
low flow period:
• Rate of snowmelt and glacial melt.
• Geologic characteristics.
• Outflow from lakes and reservoirs.
• Rate of evapotranspiration from soils and vegetation.
• Effects of upstream water withdrawals and irrigation return flows.
Hydrology
page
HY-7
-------
Figure 2. Geology modifies streamflow regime from
two watersheds with similar climates
Bad River from shale
Middle Loop
River from
sandhills
Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
Adapted from Satterlund and Adams (1992)
Several of the influencing factors may only be important in certain regions. For
instance, assessing the importance of glacial melt in sustaining late summer/early fall low
flows will be required for some watersheds located along the Pacific Northwest's Cascade
Mountain range and in Alaska, as well as a few watersheds in the Northern Rocky
Mountain and Canadian Rocky Mountain ranges. Wetlands, while present throughout
the nation, are most prevalent along the southern seaboard, gulf coast, and lower
Mississippi River and in the glacial terrain of the north-central United States.
Each region and even each watershed will have unique issues. This section will focus on
summarizing physical watershed characteristics and collecting available streamflow and
climate data in order to discern the hydrologic issues. The typical distribution of runoff
over the course of the year as well as the dominant peak flow and low flow issues in
the watershed will be investigated.
Step 1. Identify general watershed characteristics
Using the watershed base map generated in the Scoping process, review and clearly
delineate the boundaries of each identified sub-basin. Form HI can be used to
compile and organize watershed-specific hydrologic information. For each sub-basin,
page
HY-8
Hydrology
-------
identify basic watershed features such as drainage area, topographic relief (e.g., minimum
and maximum elevations), geology, drainage pattern, stream gradient, and mean annual
precipitation. If GIS support is available, some of the information can be calculated using
the computer. Otherwise, use USGS topographic maps and a map of mean annual
precipitation (from NOAA or a state agency) to estimate values for each characteristic.
Step 2. Characterize streamflow patterns
Identify gages
Identify any streamflow gages in or near the watershed of interest and develop a table
summarizing station information such as the station name, location, elevation, and period
of record.
The USGS has been operating streamflow stations across the country since the turn of the
century. In some regions, stream gages are numerous and have long periods of record,
while in other regions (e.g., west of the Mississippi), there are fewer gages and they have
shorter periods of record. The following are factors to consider in finding representative
streamflow data:
Where gages are numerous, the task will be to select the most useable and representative
gages-
Watershed size will be an important decision criterion, as will length of record; longer
records offer more insight into the variability of streamflow. To obtain representative
data for a watershed, the gage records should cover at least ten years.
The gaging station does not need to be currently in operation; historical data still offer
a glimpse into how a watershed responds to storm inputs (precipitation, temperature,
wind, etc.).
/-. r i u Box 1. Regulated watersheds
Gage records should represent a
unregulated streamflow (where
no reservoirs or diversions exist
above the gaging station). Gages
downstream of a reservoir or
even a millpond will not record
natural peak flows but will reflect
streamflow modified by the
structure (Box 1).
For watersheds with dams, large-scale diversions, or other
flow-altering activities; streamflow data remarks will need to
be reviewed in detail prior to use. The first task will be to
determine the unregulated portion of the record, prior to com-
pletion of the flow-altering activity. Summary statistics and
hydrographs developed from the unregulated portion of the
streamflow record can offer an indication of the pre-alteration
flow regimes. Techniques for deregulating the post-alteration
record can be undertaken as a Level 2 analysis.
Hydrology
page
HY-9
-------
Box 2. Criteria for assessing hydrologic
similarity of two watersheds
The USGS information office nearest the watershed can help locate an appropriate
gage or gages. If a stream gage is not located in the watershed, obtain records
for a nearby stream gage draining a hydrologically similar watershed. Gages
located in adjacent watersheds will not necessarily
be representative of conditions in the watershed
being assessed. Therefore, it is important to assess
hydrologic similarity by using the basic criteria listed
in Box 2 prior to selecting a surrogate gage. When
hydrologic similarity criteria are not met, ungaged
streamflow analysis may need to be conducted
(Box 3).
• Watershed drainage areas within the same
order of magnitude
• Similar mean watershed elevation above
the gage
• Similar precipitation and weather patterns
• Similar geology and topography
• No or insignificant out-of-stream diversions
Robison (1991)
Generate hydrographs
Obtain the mean monthly streamflow for the period
of record for each of the selected streamflow stations.
Generate a typical annual hydrograph (Figure 3) for each station. The shape of the
hydrograph provides an identifying characteristic of a watershed. If more than one
Figure 3. A typical annual hydrograph for winter storm-driven regime
300
Oct Nov Dec Jan Feb Mar Apr May Jun Jul Aug Sep
Month
page
HY-10
Hydrology
-------
Box 3. Estimating streamflow in ungaged watersheds
For watersheds where either no or minimal streamflow data are available, numerous meth-
ods exist to estimate streamflow. Only the methods that do not require extensive data or
modeling are presented here.
Flood regression equations
The USGS has developed regional flood regression equations for many areas of the
United States. These reports are typically published by state and entitled Magnitude and
Frequency of Floods. The equations can be used to estimate different flood events, such
as the 2-year flood, 25-year flood, etc., based on watershed area, precipitation, and land
cover. Inquire at the nearest USGS office about appropriate regional equations.
Area-precipitation method
In humid areas of similar geology, mean annual flow is closely related to drainage area
and mean annual precipitation. Mean flows may be estimated if 1) flow records from
nearby watersheds are available; 2) an isohyetal map is available (isohyets are contour
lines of equal precipitation); and 3) the geology of the area is relatively homogeneous.
Unit runoff method
Streamflow from a hydrologically similar watershed can be converted into runoff per unit
area (e.g., cubic feet per square mile) to estimate some of the streamflow statistics for the
ungaged watershed. Please note that these statistics are general estimates to be used to
assess relative magnitudes rather than absolute values. If there are any miscellaneous
streamflow measurements made in the watershed, these data can be compared to a
gaged station to establish a predictive relationship (i.e., regression analysis).
Surface water runoff maps
Use the USGS generalized maps of surface water runoff.
stream gaging station exists in the watershed, compare the hydrographs from each.
Consider the following questions:
• In which month or months does the majority of runoff occur?
• When do low flows occur?
• If comparing hydrographs, do they generally have the same shape, or does the timing
of runoff vary?
• Are flow patterns seasonally predictive?
• Do streams show great fluctuations in flow within seasons?
Hydrology
page
HY-11
-------
Optional Task: Where representative daily streamflow data are available, develop the
average daily hydrograph using the entire period of record. Compare daily flows over
a few years.
Aquatic Life
Flow variability is an important factor to aquatic ecosystems. The information collected
in this step may be useful to the Aquatic Life analyst. For example, the hydrographs can
be compared to the aquatic species' stream flow requirements to illustrate the timing of
streamflow in relation to the needs of aquatic life.
Aquatic Life
Summarize peak flow data
Obtain and graph the annual peak flow data associated with the selected streamflow
gages (Box 4). Enter the data into a table (similar to Figure 4) that tracks the magnitude
of annual peak flows in cubic feet per second (cfs) and the date of each peak flow.
Consider the following questions:
In which month or
months do the majority
of the annual peak flows
occur?
Do extreme high flows
occur during critical
periods for aquatic life?
Have high flows
influenced habitat
conditions?
Box 4. Annual peak flows and water years
For each station, a record of annual peak flows should
be available (see the "Data Sources" section). Annual
peak flows represent the highest recorded discharge
for that station for a given water year. The water year
differs slightly from the calendar year. Water year is
defined as the 12-month period starting on October 1
and ending on September 30. October 1, 1999,
through September 30, 2000, would be referred to as
water year 2000.
Summarize minimum flow data
Obtain and graph the annual minimum flow data associated with the selected
streamflow gages. These data are available from numerous data sources. For instance,
Box 5. Low flow frequency
Low flow statistics often include refer-
ence to the seven-day ten-year low flow
(7Q10). The 7Q10 is a statistic that rep-
resents the lowest mean discharge for
seven consecutive days that has a prob-
ability of occurring once in ten years.
the USGS Water Resources Data series, published by
state for each water year, provides summary statistics
for each station currently in operation. Among the
statistics, lowest mean daily flow can be found along
with the annual seven-day minimum (lowest mean
streamflow for seven consecutive days in a water year;
see also Box 5). Report the magnitude of low flows
and their dates of occurrence in a table similar to the
page
HY-12
Hydrology
-------
Figure 4. Sample table format for summarizing annual peak flow data
Annual peak flows for each water year of record
Station name:
Drainage area:
Station number:
Period of record:
Water year'
Peak flow
amount (cfs)
Date of
peak flow
Season of
peak flow
* October 1 - September 30
peak flow data table (Figure 4). In addition, record the minimum discharge for the period
of record of the gage. Consider the following questions:
• In which month or months do the annual minimum flows typically occur?
• Do extreme low flows occur during critical periods for aquatic life?
Aquatic Life
Step 3. Characterize precipitation patterns
Collect precipitation information
Obtain the NOAA mean annual precipitation map. Identify the climate stations nearest to
your watershed and develop a table summarizing station information, such as station name,
location, elevation, and period of record.
Summarize precipitation information
Describe the range and variability of precipitation from the mouth to the headwaters of the
watershed and among the sub-basins. In addition, obtain the average monthly precipitation
for the period of record and graph the annual distribution of precipitation. This graph of
the rate of rainfall over time is called a hyetograph. Obtain and graph the annual maximum
24-hour precipitation. Consider the following questions:
• In which month or months does the majority of precipitation occur?
• When are the dry seasons?
Hydrology
page
HY-13
-------
• In which month and year does the largest annual maximum 24-hour precipitation
event occur?
• Is this the same storm that produced one of the largest peak flows?
• In what month do most of the maximum 24-hour precipitation events occur?
Examine trends in data
If the period of record for the streamflow station and climate station overlap, examine
the pattern that has occurred for peak flows and precipitation over time. Consider the
following questions:
• Are annual peak flows consistently increasing or decreasing over a period of the record?
• Does a cyclical wet and dry pattern emerge in which short periods of lower peaks are
interspersed with periods of higher peaks?
If some pattern seems apparent, then the next step is to discern whether the pattern
mimics the climatic pattern. If there is a trend in the peak flow graph that is not apparent
in the precipitation graph, then further study may be warranted. Keep this point in mind
when proceeding with the hydrologic screening tasks. Note the year in which the trend
in peak flows becomes apparent and the year in which it stops and try to identify major
watershed changes that might have occurred coincidentally. Also be sure to review the
Historical streamflow and climate station histories to check for changes in gage locations. Check the
Historical Conditions module timeline for input on watershed changes.
Step 4. Summarize the role of qroundwater and other natural water storage
features
Natural water storage features play a role in the runoff response of the watershed. In fact,
hydrologic regimes in some regions are dominated by their storage components. "Storage-
based"systems or subsurface-dominated flow regimes typically release water slowly over
long periods of time. For instance, in the pine flatwoods of Florida, surface runoff occurs
only when the groundwater table intersects the soil surface. Conversely, most rangelands,
absent dense vegetation, offer little water storage. Surface runoff is the most common
form of conveyance as evidenced by numerous rills and ephemeral channels.
Almost all streams interact with groundwater to some extent. In fact, groundwater
discharge to streams (termed baseflow) often accounts for 50 percent or more of
page
HY-14 Hydrology
-------
the average annual streamflow. The proportion of stream water that is derived from
groundwater inflow, however, can vary considerably across physiographic and climatic
settings. Streams can interact with groundwater in one of three ways:
1. Streams gain surface water from groundwater inflow.
2. Streams lose water to groundwater by outflow through the streambed.
3- Streams do both, gaining at some times or in some reaches and losing at other times
or in other reaches.
Groundwater boundaries in many instances do not coincide with watershed boundaries;
groundwater/surface water interactions are largely controlled by the geologic setting
(Box 6). As an example of the effect that geology can have on the groundwater
contribution to streamflow, Winter et al. (1999) compared the Forest River watershed
Box 6. Hydrologically closed systems
Watersheds located in the glacial and dune
terrain (the prairie-pothole region) of the north-
central United States are characterized by hills
and depressions with many lakes and wet-
lands. While streams drain portions of this ter-
rain, typically they do not form a large drain-
age network, and stream outlets are often
absent, indicating a "closed" system. Move-
ment of water through this terrain is controlled
primarily by exchange of water with the atmos-
phere (through precipitation and evapotranspi-
ration) and with the ground water.
in North Dakota with the Sturgeon
River watershed in Michigan. The
Forest River watershed is underlain
by poorly permeable silt and clay
deposits, which limit the contribu-
tions of groundwater to streamflow
to around 14 percent of average
annual flow. By contrast, the
Sturgeon River watershed is dom-
inated by highly permeable sands
and gravels, causing the groundwa-
ter component of streamflow to be
large, approximately 90 percent of
its average annual flow.
Erosion
Antecedent precipitation conditions also influence groundwater/streamflow interactions.
During storms, a rising water level in the stream channel typically reverses the direction
of groundwater flow, causing storage of water in the floodplain and recharge of adjacent
aquifers. As the stream recedes, the stored groundwater is released slowly back to the
stream.
Vegetation
Inventory water storage features
Locate and describe surficial water storage features in the watershed such as lakes, ponds,
wetlands, and swamps. In some regions, the USGS has compiled descriptive watershed
information for each streamflow gaging station (Williams et al. 1985). The EPA Surf
Hydrology
page
HY-15
-------
Your Watershed web page (http://www.epa.gov/surf/) has information on the number
of lakes in the watershed, as well as the name, description of rock types, and square miles
of coverage for each underlying aquifer. Confer with the Vegetation analyst to obtain
the vegetation map documenting the extent of wetlands identified on the NWI maps
and through aerial photo interpretation. If information is not readily available, storage
features can be identified on topographic maps and aerial photographs.
Box 7. Karst terrain
Summarize snow data
If snow accumulates in the watershed, identify snow data collection stations in or near
the watershed. The NRCS collects snowpack depth and snow-water equivalent data at
stations in many regions. Contact the local NRCS office to determine whether snow
stations are actively monitored in or near the watershed.
Also, check with the USFS for snow data. Determine
in which sub-basins snow accumulates and, if possible,
estimate the snow pack depth.
Karst terrain refers to areas of highly disrupted surface
water drainage systems due to the dissolution of
underlying bedrock (typically limestone and dolomite).
Solution openings, rock openings, and sinkholes inter-
sect the surface, providing connection to the under-
ground drainage network. Precipitation onto areas
where karst terrain outcrops at the land surface tends
to infiltrate quickly. Even large streams can run dry as
they recharge the groundwater directly through sink-
holes and solution cavities. This direct link also leaves
groundwater resources very susceptible to pollution.
USGS studies (Brown and Patton 1995) found that
streams traversing the karst terrain associated with the
Edwards Aquifer in south-central Texas can lose con-
siderable amounts of water. Yet, karst aquifers can
also produce ample groundwater discharge. For
example, springs near the margin of the Edwards
Aquifer provide a continuous source of water for
streams to the south.
North-central Florida provides an example of a man-
tled karst region with numerous sinkhole lakes. Many
lakes in this region form as unconsolidated surficial
deposits slump into sinkholes in the underlying highly
soluble limestone of the Upper Floridian Aquifer.
Identify the presence of glaciers in the watershed.
Glacial streams, primarily during low flows, will exhibit
characteristics different from those for neighboring
streams that are fed by snowmelt, lakes, and
groundwater.
Summarize groundwater resources
Use available hydrogeologic resources, such as existing
reports, maps, and aquifer descriptions, to summarize
the knowledge of groundwater issues by sub-basin. The
USGS Groundwater Atlas provides aquifer descriptions
for most regions. Locate areas of productive
groundwater discharge in the watershed (e.g., well
fields, springs) and also potential areas of groundwater
recharge (e.g., karst terrain; Box 7).
Over the past decade, as the joint management
of groundwater and surface water resources has
come to center stage, investigators have focused on
characterizing the interactions. If the watershed is
in an area with a recently completed regional-scale
page
HY-16
Hydrology
-------
baseflow study (Box 8), use the report to
help define the role that groundwater plays
in maintaining the streamflow.
Step 5. Characterize watershed runoff
processes
Box 8. Baseflow studies
Recently completed baseflow studies are available
for several regions in the country:
• Washington State, selected rivers and streams
(Sinclair and Pitz 1999).
• The Great Lake area (Holtschlag and Nicolas 1998).
• The Chesapeake Bay area (Bachman 1997; Lang-
land etal. 1995).
• The Appalachia region (Rutledge and Mesko 1996).
• The Central Savannah River watershed (Atkins et al.
1996).
• Pennsylvania (White and Sloto 1990).
• Tennessee (Hoos 1990).
The purpose of this step is to identify the
relative importance of the runoff pathways
(surface and subsurface) within the
watershed. Using the information gathered
in Steps 2 through 4, summarize the
interaction among streamflow, precipitation
inputs, groundwater, and storage components. Discuss, to the extent possible, the
mechanisms by which runoff is generated. More than one runoff process can be active in a
watershed, and often a predictable pattern will emerge (Box 9).
A I, i j n Box 9. Example runoff descriptions
As a general rule, overland now r r
pathways are dominant in arid areas
and on paved urban areas or disturbed
landscapes where infiltration capacity
is often limited. Subsurface flow is
more prevalent in humid regions with
dense vegetation and deep, permeable
soils. Where subsurface flow is
a dominant contributor to storm
runoff, the percentage of precipitation
that reaches the stream during the
storm is low; most of the rain is
stored in the soil and groundwater,
then released slowly.
Further distinction can be made
regarding the influence of climate on
runoff. In rainfall— or rain-on-snow—dominated hydrologic regimes, annual maximum
precipitation events often occur at the same time of year as the annual peak flows.
By contrast, in areas with a snowmelt-dominated regime, maximum precipitation events
In forested watersheds draining deep soils in the Sierra Nevada
Mountains, winter snow accumulation and spring snowmelt are
the primary influences on the shape of the annual hydrograph.
However, other hydrologic processes are also active. Groundwa-
ter release sustains streamflow relatively well into the summer,
and all the more extreme peak flow events have resulted from
mid-winter rain-on-snow events. Rain-on-snow events have typi-
cally generated peak flows up to five times greater than spring
snowmelt peak flows.
Some watersheds in the unvegetated shallow cirques of the Sierra
Nevada Mountain alpine zone are snowmelt-dominated. Ground-
water may contribute only a small portion of the total annual
amounts of surface water; however, the groundwater inputs are
the primary source of water for 8 to 9 months of the year.
Hydrology
page
HY-17
-------
do not yield the largest floods; instead, spring melting of the accumulated winter
precipitation (stored in the snowpack) generates peak flows. Watersheds with extensive
wetland systems and other forms of storage will also show streamflow desynchronized
from the precipitation inputs. In arid regions, intermittent streams often yield flash
floods in response to high intensity rainstorms. The intensity of rainfall in these areas
can be a more important factor in determining runoff than the total amount of rainfall.
In the Great Plains region, thunderstorms provide more than half of the precipitation
during the growing season (Maidment 1992).
Step 6. Identify water control structures
Locate on a map the water control structures in the watershed. Man-made structures
and storage facilities such as water supply reservoirs, flood control reservoirs, and even
abandoned dams (millponds) impact the streamflow downstream of the impoundment
(Box 10). Information on the operation and physical attributes of such structures will
be instrumental in any future Level 2 analyses.
Box 10. Hydrologic impacts of reservoirs
In 1963, Glen Canyon Dam began to store water, and Lake Powell reservoir was cre-
ated along the Colorado River. Since then, the Colorado River downstream of the dam
has not experienced its natural seasonal floods. Snowmelt produced pre-dam flood
flows on the Colorado on the order of 2,400 m3/s. Since 1963, the controlled releases
from the Glen Canyon Dam have generally been maintained below 500 m3/s. In addi-
tion to modifying the streamflow, dams impede the transport of sediment downstream
by trapping it behind the dam (Poff et al. 1997).
Channel
Identify and map areas with channel modifications. Extensive levees, diking, or bank
armoring can disconnect the channel from its floodplain, which in turn can impact the
hydrologic function of the watershed. Confer with the Channel analyst to determine
the extent of channel modification.
Step 7. Characterize water use
Water use, through diversions of surface water or withdrawals of groundwater from
wells, reduces streamflow, potentially resulting in a negative impact on biological
resources. Water use is generally categorized by beneficial use designations, such as
page
HY-18
Hydrology
-------
municipal water supply, industrial water supply, irrigated agriculture, domestic water
supply, fish and wildlife, recreation, and federal reserved rights.
Identify the types of beneficial water uses in the watershed and summarize them in a table.
If overuse of either surface water or groundwater was identified as a concern during
Scoping,locate areas of concern in the watershed. For instance, several areas in the country
have pumped groundwater resources excessively, to the extent that the land surface is
subsiding.
Water
Quality
Box 11. Consumptive water use
Make generalizations about the typical schedules of withdrawals for each beneficial
use. For instance, withdrawals for irrigation may only be operated for a few
months of each year, while withdrawals for water
supply are typically year round. Characterize
the surface water withdrawals separately from the
groundwater withdrawals. Determine, if possible,
how much of the water use is consumptive
(Box 11) and the extent of imports of water
from or exports of water to other watersheds
(interwatershed transfers).
Consumptive use is the quantity of
water absorbed by a crop and tran-
spired or used directly in the building
of plant tissue together with the water
evaporated from the cropped area.
Section 2. Screen for Potential Land and Water Use Impacts on Hydrology
The screening process is designed to focus future analyses by identifying land and water
use activities in the watershed that are potentially problematic. Land use practices and
structural features, as well as water use, can modify the hydrologic regime of a watershed by
altering one or more of the following:
• Amount of water available for runoff.
• Flow available in the channel.
• Routing of water to the streams.
• Lag time (delay between rainfall and peak streamflow; Figure 5).
• Travel distance to the stream.
Each activity has its own array of potential impacts to the hydrologic resources (Table 1).
Those activities that affect the rate of infiltration or the ability of the soil surface to
store water are typically most influential. For instance, impervious surfaces associated
Hydrology
page
HY-19
-------
Figure 5. Hypothetical hydrographs demonstrating
changes between pre-urbanization (dotted curve) and
post-urbanization (solid curve) runoff
>• o
•5 E>
c
-------
Table 1. Potential hydrologic effects associated with land and water use
Land Use
Forestry
Agriculture/
rangeland
Urban
Water
control
structures
Water use
Land Use
Practice
Timber
harvest
Roads and
harvest
practices
Land
drainage
ditching
Draining
wetlands
Crop
production
Cattle
grazing
Increase in
impervious
surfaces
Use of
storm water
facilities
Dams and
diversions
Levees and
channelization
Surface water
diversions
Groundwater
pumping
Return flow
Hydrologic
Component
Affected
Peak flow
Low flow
Peak flow
Annual yield
Peak flow
Low flow
Peak flow
Low flow
Low flow
Peak flow
Peak flow
Low flow
Peak flow
Peak flow
Peak flow
routing
Low flow
Low flow
Low flow
Potential Hydrologic Effects
Increased peak flows due to reduction in evapotranspiration and interception
as well as more accumulation and melt of snowpack. Diminished impact as
regrowth occurs even though damage to the channels may persist.
Increased low flows due to reduction in evapotranspiration and interception.
Rerouted subsurface flows to surface runoff through roadside drainage
ditches. Compaction of soil causes increased runoff and decreased
infiltration. Logging practices such as skid trails contribute to the same effect.
Increased water yield due to more accumulation of snowpack in open areas
and reduction in evapotranspiration and interception. Most of increase occurs
during wet part of the year.
Increased timing of storm runoff as surface flow moves more quickly to
stream.
Lowered water table. Reduced groundwater recharge.
Increased timing of storm runoff as surface flow moves more quickly to
stream.
Lowered water table. Reduced groundwater recharge.
Altered rates of transpiration affects runoff.
Increased timing of storm runoff due to compaction of soils. Reduced
infiltration.
Reduced infiltration. Surface flow moves more quickly to stream, causing peak
to occur earlier and to be larger. Increased magnitude and volume of peak.
Can cause bank erosion, channel widening, downward incision, and
disconnection from floodplain.
Reduced surface storage and groundwater recharge, resulting in reduced
baseflow.
Increased timing of runoff through increased velocity due to lower friction in
pipes and ditches. Surface flow moves more quickly to stream via pipes and
ditches, causing peak to occur earlier and to be larger. Increased total volume.
Reduced magnitude and frequency of high flows. Can cause channel
narrowing downstream of dam. Capture of sediment behind the dam can result
in downstream channel erosion and bed armoring.
Reduced overbank flows. Isolation of the stream from its floodplain. Channel
constriction can cause downcutting.
Depleted streamflow by consumptive use. Streamflow depleted between point
of withdrawal and point(s) of return.
Lowered water table. If hydraulically connected, can cause streambank
erosion and channel downcutting after loss of bank vegetation.
Altered timing of groundwater/surface water interaction.
Hydrology
page
HY-21
-------
problems and to determine the magnitude of impacts. Outlining a detailed assessment
process that relies on hydrologic techniques is beyond the scope of this document;
however, general guidance for more extensive analyses is provided in the "Level 2
Assessment" section.
Step"!. Summarize land uses
Inspect the land use map from the Scoping process and identify the land uses present
in each sub-basin. Validate the boundaries around the mapped land uses using aerial
photos, orthophotos, or topographic maps and correct any inaccurate boundaries. Use
this corrected land use map to determine the area (acres or mi2) of forestry, agriculture,
rangeland, urban, rural residential, and other land uses in each sub-basin. The areas in
each land use can be determined using GIS, calculated using a planimeter, or estimated
using the rectangular grid method. Identify the location of structural features on the
map, and identify the point of diversion for each significant water use.
Enter the area estimated for each land use in each sub-basin into a table similar to
Figure 7-
Figure 7. Sample table format for summarizing land use data
Land use categories (% of watershed area)
Sub-basin
name
Rural
Forestry Agriculture Rangeland Urban residential Other
Entire
watershed
Step 2. Screen for potential forestry issues
If commercial forestry is a land use activity in the watershed, then the existing condition
of the forest stands in the watershed will need to be assessed. Further investigation will
page
HY-22
Hydrology
-------
be needed if the canopy cover of the current forest stand is substantially different from
its historical condition. In addition, extensive harvesting within the last few decades
may have substantially impacted the hydrology. Confer with the Vegetation analyst to
obtain work products and general information on the changes in forest canopy over
time. Consult with agency hydrologists or foresters as needed to determine whether
regional criteria for harvest management are available or whether there are regional
forestry issues that need to be addressed. For instance, much of the timber harvest in the
southeastern United States comes from lands occupied by a high percentage of forested
wetlands. Impacts of timber harvest on hydrology in this region should specifically
address wetlands.
Vegetation
For sub-basins in which commercial forestry raises concern, enter a "Yes" on Form H2.
Further investigation may not be warranted if forestry occupies only a small portion
of a sub-basin or the vegetative cover condition has not changed substantially; in this
case, a "No" may be the appropriate response on Form H2. For sub-basins in which no
commercial forestry occurs, enter an "N/A" on Form H2.
Step 3. Screen for potential agriculture or ranaeland issues
Box 13. Example of a regional agriculture
issue—peat mining in North Carolina
If agriculture activities or rangeland management occurs in a sub-basin, several questions
regarding soil type and agricultural practices will need to be addressed. The impact
of agriculture on hydrology is dependent on specific practices such as the type of
cover and management treatments, as well as
the characteristics of the soil being farmed
(Box 13). The infiltration rates of undisturbed
soils vary widely. Agriculture has a greater
effect on runoff in areas where soils have a
high infiltration rate than in areas where soils
are relatively impermeable in their natural
state (USDA Soil Conservation Service
[SCS] 1986). Impacts associated with the
utilization of rangelands can be assessed in a
manner similar to that used for agricultural
lands. In addition, cattle grazing on sparsely
forested lands can have similar impacts and
should be considered under this heading.
A study on the Coastal Plain of North Carolina
(Gregory et al. 1984) found the following
hydrologic impacts associated with peat mining:
• Greater volume, duration, and peak flow of
storm discharge from the field ditches on
the mining sites than from sites with natural
vegetation.
• Quicker overland flow to the ditches on the
mining site due to reduced infiltration asso-
ciated with grading the surface.
• Lower baseflows in the ditches draining the
mined sites.
Hydrology
page
HY-23
-------
The USDA has characterized and mapped the soils for most areas across the United
States. Other agencies, such as state land managers and the USFS, are also sources of
soil information. As part of the mapping process, soils are classified into one of four
Erosion hydrologic soil groups (Table 2), primarily as a function of their minimum infiltration
rate on wetted bare soil. Confer with the NRCS specialist nearest the watershed to
locate soil group information, typical agricultural practices in the watershed, and any
regionally specific crops.
Use the percentage of the sub-basin in agriculture, knowledge of associated soil groups,
and typical agricultural practices to help determine whether agricultural concerns exist.
Enter a "Yes," "No," or "N/A" response on Form H2 for each sub-basin.
Table 2. Hydrologic soil group classification
Hydrologic
soil group
Characteristics of soils
Low Runoff High infiltration rates even when thoroughly
Potential wetted. Deep, well drained sands or gravels with
A a high rate of water transmission. Sand, loamy
sand, or sandy loam.
B
D
High Runoff
Potential
SCS (1986)
Moderate infiltration rates when thoroughly
wetted. Moderately deep to deep, moderately well
to well drained, moderately fine to moderately
coarse textures. Silt loam or loam.
Slow infiltration rates when thoroughly wetted.
Usually has a layer that impedes downward
movement of water or has moderately fine to fine
textured soils. Sandy clay loam.
Very low infiltration rate when thoroughly wetted;
chiefly clay soils with a high swelling potential;
soils with a high permanent water table; soils with
a clay layer near the surface; shallow soils over
near impervious materials. Clay loam, silty clay
loam, sandy clay, silty clay, or clay.
Minimum
infiltration rate
(mm/hr)
8- 12
4-8
1 -4
0- 1
page
HY-24
Step 4. Screen for potential urban, suburban, or rural residential issues
For sub-basins with urban, suburban, or rural residential development, the screening
process will rely on estimating the impervious area as the basis for determining
Hydrology
-------
Table 3. Average area of impervious surfaces, urban and residential
development
potential hydrologic impacts. Impervious surfaces are those that prevent or inhibit the
natural infiltration process, such as roads, parking lots, and rooftops. Table 3 displays
the average percentage impervious
area associated with various types of
development. For each sub-basin,
use the land use map and aerial
photos to estimate the area occupied
by the most common types of
development. Multiply this area
by the average impervious area
percentage from Table 3 to obtain
an estimate of the sub-basin total
impervious area (TIA). If it is
not possible to identify the areas of
development types, a TIA estimate
can be made based on road density
(Box 14).
Type of land development
Urban Districts:
Commercial and business
Industrial
Residential Districts by
Average Lot Size:
1/8 acre or less (town houses)
1/4 acre
1/3 acre
1/2 acre
1 acre
2 acre
SCS (1986)
Average impervious
85
72
65
38
30
25
20
12
area (%)
Optional Task: Compute the weighted average percentage impervious value for all
development types in the sub-basin.
Box 14. Using road density to estimate impervious area
If difficulties arise in estimating impervious areas, the extent of develop-
ment can often be expressed in terms of road density. May et al. (1997)
established a relationship between watershed urbanization (percentage
TIA) and sub-basin road density (mi/mi2) that can be used as a surro-
gate for percentage impervious surfaces in the Pacific Northwest. In
urbanized areas of the Pacific Northwest when road densities equal or
exceed 5.5 mi/mi2, TIA probably exceeds 10 percent.
Concern for potential urban-related hydrologic issues should arise for each sub-basin that
exceeds a regionally appropriate percentage impervious area threshold. For Puget Sound
Lowland streams in Washington, May et al. (1997) recommend that impervious area be
limited (< 5-10 percent TIA) to maintain stream quality, unless extensive riparian buffers
are in place. Consult agency hydrologists or research in the vicinity of the watershed
to develop a threshold of concern applicable to the watershed. Schueler's (1994) review
Hydrology
page
HY-25
-------
of 18 urban stream studies revealed that a sharp decline in species diversity was often
associated with 10 percent or greater TIA.
Based on the estimated total impervious area in the watershed, designate sub-basins in
which urban use is of concern by entering a "Yes" or "No" response on Form H2.
Step 5. Screen for potential water control structure issues
For sub-basins with man-made water control structures and storage facilities, determine
the portion of the watershed influenced by each structure. Each reservoir has its own
operating scheme and, therefore, will require more detailed hydrologic investigations,
often including release schedules, reservoir routing, etc. If there is a sizable reservoir
in the watershed, further technical analyses will be required for the portion of the
watershed below the dam, but some of the steps can be completed for the land uses
present in the portion of the watershed above the dam. Consult with hydrologists at the
Bureau of Reclamation, USAGE, public utilities, or local reservoir operators to obtain
information about the operating scheme.
Other types of structures, such as dikes, levees, or channelization, can affect the
Channel hydrologic function of a watershed because they modify channel configuration. Confer
with the Channel analyst to assess reaches of concern.
In consultation with agency hydrologists and using data collected in the characterization
section, determine the extent to which the structures may be altering the hydrology of
the watershed. Sub-basins in which structures may cause changes to the hydrology will
require further study and should receive a "Yes" response on Form H2.
Step 6. Screen for potential water use issues
For sub-basins in which water is being withdrawn from either surface or groundwater,
comparisons of stream flow to water use will be necessary. Determine the time of year
when water use is the highest. If possible, compile estimates of monthly water use based
on information collected in Step 7 of Section 1.
In many regions throughout the country, high demand for water occurs during the low
flow season. The reduction of streamflow due to water use is of particular concern
page
HY-26 Hydrology
-------
during the low flow season. Consider whether a pattern emerges when comparing monthly
streamflow to monthly water demand.
Further investigation of water use and allocation issues may be warranted if consumptive
use is high in one or more sub-basins, particularly if the low flow period coincides with
times of high water use. In addition, while the impact to low flows of a surface water
withdrawal is fairly straightforward to account for and immediately felt, the impact of
groundwater withdrawals on nearby streams is not as easily understood. Characterizing
the groundwater/surface water interactions (termed hydraulic continuity) may be necessary
in areas where water use and water supply requirements are competing with fisheries
protection measures, such as enforcing minimum in-stream flows.
In consultation with agency hydrologists and using data collected in the characterization
section, determine the extent to which water use is depleting streamflow. Sub-basins in
which water use may be a concern will require further study and should receive a "Yes"
response on Form H2. Sub-basins with minimal water use may not need further study.
Step 7. Produce Hydrology report
Generate a brief report summarizing the information gathered. The report should feature
the tables, graphs, and forms produced as well as a narrative describing the hydrologic and
climatic character of the watershed and the potential land and water use impacts.
page
Hydrology HY-27
-------
Level 2 Assessment
Once the initial watershed characterization and the screening for potential impacts have
been completed, the focus of future assessment efforts should be reasonably clear. This
section provides a general discussion of available options for Level 2 characterization and
analyses. The Level 2 methods and specific tools required will differ for each watershed
depending on issues revealed during the Level 1 assessment. Level 2 analyses will be
more technical and extend the level of detail beyond that used in Level 1 (see Hydrology
Module Reference Table).
Level 2 Characterization
Streamflow patterns
The methods for a Level 2 characterization of Streamflow will be a function of available
data and Level 1 products. For Level 2 analyses, determination of Streamflow for each
sub-basin will be necessary to assess the patterns and trends over time. Level 2 methods
may include the following:
• Applying Streamflow statistics from one gage location to another point in the
watershed (e.g., applying unit runoff from an upstream point to the mouth of a
watershed).
• Using regional regression equations for watersheds that are ungaged and have no
Streamflow records.
• Using correlation techniques for stations with short periods of record and extending
them using long-term data from another gage that drains a hydrologically similar
watershed.
Statistical information on extreme events generated through flood frequency analyses
(e.g., log pearson type III), low flow frequency analyses, or 7Q10s can provide perspective
on the range of expected extreme flows. Frequency analyses can be performed using
annual peak flow series data or partial series data.
* Aquatic Life
^ Water Quality
Flow duration curves provide an excellent way to represent Streamflow data to better
target pollution sources and effective management strategies. A flow duration curve
is the cumulative frequency of stream flow without regard to the chronology of
page
HY-28 Hydrology
-------
occurrence (Leopold 1994). Flow duration curves represent the percentage of time a
given value of stream flow will be exceeded (Figure 8). Thus, the highest streamflows
on record (i.e., flood conditions) will correspond to the lowest percentages, whereas the
lowest streamflows (i.e., drought conditions) will correspond to the highest percentages.
Duration curves generally reflect average daily flows but may also represent weekly or
monthly flows.
Figure 8. A hypothetical example of a flow duration curve based on mean daily stream
flow.
o 10
Flood
30 40 50 60
Percent of Time Flow Exceeded
70
80
90 100
Draught
Since nonpoint source pollution is often driven by runoff events, watershed management
plans orTMDL development may need to target different factors across the range of flow
conditions to restore water quality (Cleland 2002). Flow duration curves can help to
diagnose the source of problems and target specific activities or areas for improvement.
For example, if exceedence of water quality criteria occur at low flows, point sources of
pollution are likely to be targeted, whereas if exceedence occurs at high flows, nonpoint
sources and land management activities may need to be targeted. Figure 9 provides a
hypothetical example showing higher suspended sediment values at high flows, potentially
indicating a problem with non-point sources of sediment or bank erosion. Flow duration
curves may also be useful in evaluating pollutant load trading to ensure that the timing
and amount of pollutant load exchange provides adequate water quality protection. Flow
Hydrology
page
HY-29
-------
duration curves may be particularly helpful in providing insights for the Aquatic Life
and Water Quality modules."
Figure 9. A hypothetical example relating the annual flow duration curve with
suspended sediment pollutant load.
1000
0.01
0 10 20 30 40 50 60
Flood Percent of Time Flow Exceeded
70
80
90 100
Drought
Precipitation patterns and other climate data
Data from additional precipitation and snow stations can help to further characterize the
precipitation patterns and their influences on the hydrologic regime. Data from more
than one station along with NOAA maps or PRISM (Parameter-elevation Regressions
on Independent Slopes Model) maps developed by Oregon Climate Service (http://
www.ocs.orst.edu/) can be used to determine precipitation distribution throughout
each sub-basin. Multiple station data can also be useful for evaluating the impacts
of elevation and aspect on hydrologic processes such as rain, snow, or a combination
thereof. Precipitation frequency analyses reveal the magnitude and frequency of extreme
precipitation events. Level 2 analyses typically rely on additional climate data such as
temperature, wind, and evaporation data.
page
HY-30
Hydrology
-------
Trend analyses
Level 2 analyses may involve detecting trends in the streamflow or climate parameters.
A trend can be defined as a systematic increase or decrease over time of one particular
parameter (e.g., streamflow or temperature). Several options for detecting underlying
trends in time-series data sets are available. The first step is often to perform some type
of smoothing technique such as a moving average to reduce the effects of non-systematic
variation in flows. Moving averages can be calculated for different time periods (e.g.,
5-year or 10-year moving averages) depending on the availability of data. The Mann-
Kendall nonparametric test can be used to discern monotonically increasing or decreasing
trends in streamflow or precipitation data (Maidment 1992).
A double mass analysis is useful for the detection of changes in relationships between two
monitoring stations. This may become important if the location of a station has changed
over its period of record or if a change in land use practices has occurred around one
station but not the other.
Groundwater and other natural storage
Level 2 analyses may require further definition of groundwater issues. The average daily
hydrograph of surface water can be used to evaluate baseflow characteristics that are
usually supplied by groundwater discharge. Groundwater/surface water interactions can
be qualitatively addressed by examining a graph of the logarithm of discharge versus time.
The slope of the recession on this graph indicates the role of groundwater in sustaining
baseflows. The groundwater component of streamflow can also be evaluated using a
computer-based hydrograph separation technique (such as HYSEP [Sloto and Grouse
1996]) or summary statistics from the daily minimum streamflow records. Surficial
aquifers can be delineated and mapped based on comparisons of physical properties such
as depth to groundwater, surficial geology, soil properties, and the presence or absence of
near-surface aquitards (geological strata that limit groundwater seepage).
Monthly or daily tracking of hydrologic components in a water budget may provide more
information on the state of the water table fluxes, the lags between storage components,
and ultimately, the impact of groundwater and other storage on streamflow. This can be
accomplished using a spreadsheet or a watershed hydrologic model such as BASIN (see
Table 4 in the "Land Use" section, below).
page
Hydrology HY-31
-------
Runoff generating processes
The compilation of daily streamflow and climate data for the duration of typical storms
can be useful for further characterizing the watershed's runoff response. For instance,
in areas where rainfall duration has a large influence on producing watershed runoff,
daily precipitation values for several days prior to and including the day of the annual
peak flows will be helpful in detecting patterns. In other areas where rainfall intensity
may strongly influence the generation of runoff, collection of data on the rates of rainfall
throughout a day may offer insight into watershed processes.
In still other areas, runoff may result primarily from the combination of rainfall and
water resulting from snowmelt during the storm. Collection of temperature and
snowpack data prior to and during the time of annual peak flow events will help to
determine the propensity for snowpack to contribute melt water during storms; these
storms are referred to as rain-on-snow events.
Level 2 Analysis
Water control structures
Level 2 analyses of water control structures will include techniques tailored to the
physical setting and operating scheme of each structure. Reservoir routing, watershed
modeling, and other techniques may be necessary to assess impacts of different operating
rules on downstream flows or to deregulate streamflow records. Supporting statistics
can be generated to respond to specific inquiries. For example, the Kootenai Tribe of
Idaho posed the following question: Has the dam changed the season in which floods
typically occur (Box 15)? Other questions may arise regarding changes to the magnitude
of flooding. For larger, multi-purpose reservoirs, operators typically employ continuous
hydrologic models to forecast inflows, estimate lake levels, and schedule outflows. These
models have been calibrated to the watershed and may provide a useful tool for the
Level 2 assessment.
In watersheds with numerous small diversion structures, water use may become the
focus such that Level 2 analyses will need to include quantification of the cumulative
impacts numerous withdrawals may have on seasonal low flows.
Water use
page
HY-32 Hydrology
-------
Box 15. Analysis of dam effects on the Kootenai River, Idaho
The Kootenai Tribe of Idaho recently completed a Kootenai River Watershed Assessment (Sa-
sich et al. 1999). As part of this assessment, impacts of a dam were investigated. The table
below summarizes the number of peak flood events in the pre-dam period compared to the post-
dam period. The analysis was completed for three time categories that represent critical life
stages for the aquatic species of concern in the watershed. This investigation demonstrates that
the temporal sequence of floods has been substantially altered by the dam operations; a higher
percentage of floods has occurred from November to March in the post-dam period than in the
pre-dam period. Also, more floods occurred in the pre-dam period between April 15 and June 30
than after the dam was constructed.
Peak Floods at Leonia Gage (includes annual and partial series data)
Pre-dam
(water year 1929-71)
Post-dam
(water year 1972-98)
Time period
Number of floods
% of total Number of floods
% of total
April 15 - June 30
July - October
November - March
90
7
1
92
7
1
9
7
12
32
25
43
A relatively easy way to initially characterize water use in a watershed is to tabulate
the designated beneficial uses for both the surface and groundwater rights that are
on file with the state agency responsible for water law
administration. Water rights have different entitlements
across the country depending on the water law in
effect (Box 16). Understanding the implications of the
applicable water law will be necessary for completing a
Level 2 analysis.
Water rights, diversions, and use can be tracked by
employing a water allocation model or a spreadsheet
depending on the complexity of the situation. A
water allocation model accounts for natural inflows,
diversions, consumptive use (depletions), and return
flows based on the state water laws. Output can provide
the physical and legal availability of water for the reaches
and time periods designated. A water allocation model
tracks human uses of water while a hydrologic water
Box 16. Water law and water rights
Currently, 29 eastern states utilize the riparian rights sys-
tem, in which a landowner is entitled to the use of the
water bordering his or her property. Water law in the
western states is based on the prior appropriation doc-
trine or "first in time, first in right." Approximately 10
states use a hybrid system that combines attributes from
the riparian rights and the prior appropriation doctrine.
The prior appropriation doctrine entitles the most senior
appropriators to divert water prior to any water rights
holders with a later date (junior). Indian reservations,
national forests, national parks, and BLM lands are all
examples of federal reservations. These entities main-
tain federal reserved rights for the purposes for which the
reservation was established and the priority date of the
water right is the date the reservation was established.
Hydrology
page
HY-33
-------
balance model simulates the natural watershed processes that depend on climate inputs
(precipitation, temperature, wind, solar radiation, etc.) and the physical parameters such
as soil type and condition, geologic and topographic features, vegetative cover, and
channel location.
Water allocation calculations can track the inflows and outflows of water, spatially and
temporally. The spatial scale at which to operate a model must be carefully chosen.
Calculating water allocation on an annual basis at the mouth of a river may show
plenty of water. However, calculation at several locations in the same watershed on
a monthly or biweekly schedule may reveal problems that a more aggregated water
budget may mask.
In many regions, instream rights have become common as a means of protecting the
biological resources. In-stream flows have been established and, in some cases, a water
right has been awarded under the state agency in charge. In some states, in-stream flows
are synonymous with minimum flows; however, many contend that in-stream flows
should be set at a reasonable amount of flow to sustain biological resources, which is not
the same as a minimum flow. Comparison of instream flow rights to the minimum flow
records at several points in a watershed can help identify reaches of concern for fisheries
and other biological resources.
Actual water use does not always measure up to the amount designated on water rights
certificates. In some cases, illegal uses of water occur, abandoned rights exist, or certain
rights are not used to their full extent. Collection of actual water use data can add more
detail to a study aimed at the identification of reaches of concern. State departments
of health, conservation districts, and agricultural extension offices are good sources of
actual water use data as are records from the individual water purveyors in a watershed.
Investigations that address hydraulic continuity will be essential in some watersheds.
The formulation of specific technical questions along with knowledge of the available
data will assist in determining the approach for further hydrogeologic investigations.
In some watersheds, the timing of potential surface water capture by groundwater may
be important, while in other watersheds the analyst may only be interested in a spatial
analysis that defines the zone of hydraulic connectivity to a certain surface water source.
In areas where extensive groundwater data are available, a complex numerical model,
such as ModFlow, can be employed to determine the magnitude, distribution, and
timing of hydraulic effects.
page
HY-34 Hydrology
-------
Land use
Although it is fairly straightforward to identify the potential for a land use problem,
attempting to quantitatively assess the magnitude of the problem or the hydrologic
change is complex. The impacts of land uses on hydrology will vary from region to
region and even from watershed to watershed. So too will the selection of appropriate
analysis tools. Selection from the many options of technical tools will depend upon the
available input data and the specific questions that need to be addressed. The available
tools range in complexity from empirical equations to storm hydrograph methods to
mechanistic hydrologic models operated on a daily time step or even finer detail.
Table 4 identifies several techniques that may be useful, but it by no means constitutes
a definitive list.
Continuous models can be applied at the watershed scale and may be necessary to
assess cumulative impacts of several land uses in a watershed. For assessing urban
impact from small, developed areas, unit hydrographs can be used (e.g., Santa Barbara
Unit Hydrograph, Colorado Unit Hydrograph). Analysts assessing urban impacts may
need the ability to route stormwater through drainage networks, while analyses of
forestry impacts will need to address changes in forest cover as well as the differential
accumulation and melt of snow. Snowmelt models may also be necessary in rangelands
as snowmelt can often be an important element in many rangeland areas. In addition,
the impact of the road network on the routing of surface water in rural and forest
settings should be addressed in Level 2 analyses.
The single event hydrograph model TR55, based on the SCS runoff curve number
technique, is probably the most commonly used tool applied to the agricultural setting.
The curve number technique was originally developed for predicting changes in storm
runoff volume associated with changing land management practices. More complex
tools include BASIN, developed by the Bureau of Reclamation, Nebraska-Kansas Office.
The BASIN program computes irrigation farm delivery requirements, project diversion
requirements, groundwater diversion recharge, or watershed outflow, depending on how
the model is configured. In addition, BASIN will compute streamflow depletions or
net change in groundwater recharge due to a change in cropping patterns or irrigated
acreage.
page
Hydrology HY-35
-------
Keep in mind that many of the hydrologic tools and models suggested here (Table 4)
are capable of evaluating impacts from several land uses while others perform well
only for specific land uses. For example, TR55 was developed using data from small
rural/agricultural watersheds and has proved useful in rural catchments for comparison
of runoff under differing vegetative cover conditions. TR55 has not performed as well
in steep forested watersheds where subsurface pathways are dominant (Fedora 1987).
The applicability of many of the tools will be limited to the region in which they were
developed, while others will be useable across the country.
Table 4. Examples of hydrologic tools for Level 2
Land use
Examples of hydrologic models or technical tools and contact entity
Forestry • Washington State Watershed Analysis Methodology - Washington Forest
Practices Board (WFPB 1997)
• DRAIN MOD/DRAIN LOB - North Carolina State University
• Antecedent Precipitation Index (API) - Oregon State University
• DHSVM (Distributed Hydrologic Soils Vegetation Model) - Dennis Lettenmaier,
University of Washington, Seattle, Washington
Agriculture/rangeland
TR55-NRCS
DRAINMOD - North Carolina State University
Basin - Bureau of Reclamation
Simulating Production and Utilization of Range Land (SPUR) - USDA
HFAM (Hydrologic Forecasting & Analysis Model) - Norm Crawford,
HYDROCOMP, Inc., Palo Alto, California
Urban/rural residential
Hydrologic Simulation Program Fortran (HSPF) - EPA
HFAM (Hydrologic Forecasting & Analysis Model) - Norm Crawford,
HYDROCOMP, Inc., Palo Alto, California
Water Resources Evaluation of Nonpoint Silvicultural Sources Model
(WRENSS) - USFS
PRMS (Precipitation Runoff Modeling System) - George Leavesly, USGS,
Denver, Colorado
Regionalized Synthetic Unit Hydrograph methods (e.g. Santa Barbara,
Colorado unit hydrograph)
Stormwater runoff network models (e.g., KYPIPE, Waterworks)
page
HY-36
Hydrology
-------
References
Atkins, J. B., C. A. Journey, and J. S. Clarke. 1996. Estimation of ground-water
discharge to streams in the Central Savannah River Basin of Georgia and
South Carolina. U.S. Geological Survey, Water Resource Investigations Report
96-4179, Atlanta, Georgia.
Bachman, L. J. 1997- Groundwater nitrate loads in non-tidal tributaries of Chesapeake
Bay 1972-92. American Geophysical Union, EOS Transactions 78(46).
Bicknell, B. R., J. C. Imhoff, J. L. Kittle, Jr., A. S. Donigian, Jr., and R. C.
Johanson. 1997- Hydrological simulation program-Fortran, user's manual
for version 11. U.S. Environmental Protection Agency, National Exposure
Research Laboratory, EPA/600/R-97/080, Athens, Georgia.
Black, P. E. 1991- Watershed hydrology. Prentice-Hall, Inc., Englewood Cliffs, New
Jersey.
Branson, E A, G. E Gifford, K. G. Renard, and R. E Hadley. 1981. Rangeland
hydrology. Range Science Series No. 1, second edition. Kendall/Hunt
Publishing Co., Dubuque, Iowa.
Brown, D. S., and J. T. Patton. 1995- Recharge to and discharge from the Edwards
Aquifer in the San Antonio area, Texas. U.S. Geological Survey, Open-File
Report 96-181, San Antonio, Texas.
Cleland, B. 2002. TMDL development from the "bottom up" - Part II: Using
duration curves to connect the pieces. August 15, 2002. American Clean
Water Foundation, Washington, D.C.
Dunne, T, and L. Leopold. 1978. Water in environmental planning. WH. Freeman
and Company, San Francisco, California.
Fedora, M. A. 1987- Simulation of storm runoff in the Oregon Coast Range. U.S.
Department of Interior Bureau of Land Management, Technical Note 378,
Denver, Colorado
page
Hydrology HY-37
-------
Gregory, J. D., R. W Skaggs, R. G. Broadhead, R. H. Culbreath, J. R. Bailey, and
T. L. Foutz. 1984. Hydrologic and water quality impacts of peat mining
in North Carolina. The Water Resources Research Institute, Report No. 214,
North Carolina State University.
Heath. 1984 Ground-water regions of the United States. U.S. Geological Survey,
Water-Supply Paper 2242, Reston, Virginia.
Holtschlag, D. J., and J. R. Nicolas. 1998. Indirect ground water discharge to the Great
Lakes. U.S. Geological Survey, Open-File Report 98-579-
Hoos, A. B. 1990. Recharge rates and aquifer hydraulic characteristics for selected
drainage basins in middle and east Tennessee. U.S. Geological Survey, Water
Resources Investigation Report 90-4015, Nashville, Tennessee.
Kattelmann, R. C., N. H. Berg, and R. Rector. 1983- The potential for
increasing streamflow from Sierra Nevada watersheds. Water Resources Bulletin
19(3):395-
Langland, M. J., P. L. Lietman, and S. Hoffman. 1995- Synthesis of nutrient and
sediment data for watersheds within the Chesapeake Bay drainage basin. U.S.
Geological Survey, Water Resources Investigations Report 95-4233, Denver,
Colorado.
Leavesley, G. H., R. W Lichty, B. M. Troutman, and L. G. Saindon. 1983-
Precipitation-runoff modeling system: user's manual. U.S. Geological Survey,
Water-Resources Investigations Report 83-4238, Denver, Colorado.
Leopold, L. B. 1968. Hydrology for urban land planning: a guidebook on the
hydrologic effects of urban land use. U.S. Geological Survey, Circular 554,
Washington, D.C.
Leopold, L.B. 1994. A View of the River. Harvard University Press. Cambridge, MA.
Maidment, D. R. 1992. Handbook of hydrology. McGraw-Hill, New York, New
York.
page
HY-38 Hydrology
-------
May, C. W., E. B. Welch, R. R. Homer, J. R. Karr, and B. W. Mar. 1997- Quality
indices for urbanization effects in Puget Sound lowland streams. Final report
prepared for Washington Department of Ecology, Centennial Clean Water
Fund Grant, Water Resources Series, Technical Report No. 154, Olympia,
Washington.
May, C. W, R. R. Homer, J. Karr, B. W. Mar, and E. B. Welch. 1997- Effects
of urbanization on small streams in the Puget Sound Lowland ecoregion.
Watershed Protection Techniques 2(4):483-493-
McCammon, B., J. Rector, and K. Gebhardt. 1998. A framework for analyzing the
hydrologic condition of watersheds. U.S. Department of Agriculture Forest
Service and U.S. Department of the Interior Bureau of Land Management,
BLM Technical Note 405-
Miller, J. E, R. H. Frederick, and R. J. Tracey. 1973- Precipitation-frequency atlas
of the western United States, Volume X: Oregon. National Oceanic and
Atmospheric Administration, NOAA Atlas 2, Silver Spring, Maryland.
Otradovsky, F. 1981. BASIN user's manual. North Platte River Projects Office, Mills,
Wyoming.
Poff, L. N., J. D. Allan, M. B. Bain, J. J. Karr, K. L. Prestegaard, B. D. Richter, R. E.
Sparks, and J. C. Stromberg. 1997 The natural flow regime: a paradigm for
river conservation and restoration. Bioscience 47(11):769-784.
Robison, E. G. 1991. Water availability for Oregon's rivers and streams, Volume 1:
Overview. Oregon Water Resources Department, Hydrology Report #1.
Ross and Associates Environmental Consulting, Ltd. 1998. Recommended technical
methods for evaluating the effects of ground-water withdrawals on surface water
quantity. Draft report of the Technical Advisory Committee on the Capture
of Surface Water by Wells.
Rutledge, A. T, and T O. Mesko. 1996. Estimated hydrologic characteristics of
shallow aquifer systems in the Valley and Ridge, the Blue Ridge, and the
Piedmont physiographic provinces based on analysis of streamflow recession
page
Hydrology HY-39
-------
and base-flow. U.S. Geological Survey, Professional Paper 1422-B, Washington,
D.C.
Sasich, J., P. Olsen, and J. Smith. 1999- Kootenai River watershed assessment, final
report. Prepared for the Kootenai Tribe of Idaho.
Satterland, D. R., and P. W. Adams. 1992. Wildland watershed management. John
Wiley and Sons, Inc., New York, New York.
Schueler, T. 1994. The importance of imperviousness. Watershed protection techniques
Sinclair, K. A., and C. E Pitz. 1999- Estimated baseflow characteristics of selected
Washington rivers and streams. Water Supply Bulletin No. 60, Washington
Department of Ecology, Publication No. 99-327, Olympia, Washington.
Skaggs, R. W 1990. DRAINMOD user's manual. North Carolina State University,
Raleigh, North Carolina.
Sloto, R. A., and M. Y Grouse. 1996. HYSEP: A computer program for streamflow
hydrograph separation and analysis. U.S. Geological Survey, Water Resources
Investigation Report 96-4040, Lemoyne, Pennsylvania.
Sun, G., S. G. McNulty, J. P. Shepard, D. M. Amatya, H. Riekerk, N. B. Comerford,
R.W Skaggs, and L. Swift Jr. 1999- Effects of timber management on wetland
hydrology in the eastern United States. National Council of the Paper Industry
for Air and Stream Improvement, Forested Wetlands Research, Gainesville,
Florida.
U.S. Department of Agriculture Soil Conservation Service (SCS). 1985- National
engineering handbook, Section 4, Hydrology. SCS, Washington, D.C.
U.S. Department of Agriculture Soil Conservation Service (SCS). 1986. Urban
hydrology for small watersheds. SCS, Technical Release 55, Washington, D.C.
U.S. Geological Survey (USGS). 1979- Magnitude and frequency of floods in western
page
HY-40 Hydrology
-------
Form H1. General watershed characteristics
Watershed Name:
Sub-basin information:
Sub-basin
name
Total
watershed
Sub-basin
area (mi^)
Mean
elevation (ft)
Minimum
elevation (ft)
Maximum
elevation (ft)
Mean annual
precipitation (inches)
• Mean annual precipitation can be estimated from the Mean Annual Precipitation Map (from NOAA)
• Minimum and maximum elevations can be estimated from the base map or USGS quad maps.
Describe the type and extent of natural storage (lakes, wetlands, etc.) in the watershed.
What watershed changes have occurred that will affect streamflows (i.e., dams, major diversions for urban water
supply, irrigation diversions, industrial use, etc.)?
Information on stream gages in watershed: (Note: if more than one gage, fill out additional forms.)
Gage #:
Gage name :
Gage elevation:
Drainage area to gage:
Storage or regulation upstream of gage (yes or no)? If yes, describe on back of sheet
Hydrology
page
HY-41
-------
Form H2. Summary of hydrologic issues by sub-basin
Sub-basin
name
Entire
watershed
Potential
forestry
issue?
Potential
agriculture or
rangeland issue?
Potential urban
or residential
development issue?
Potential water
control structure
issue?
Potential
water use
issue?
Describe the rationale
behind the responses
page
HY-42
Hydrology
-------
Channel
-------
Background and Objectives
Stream channels are shaped by a number of important factors that interact to create
characteristics unique to each stream. Some factors, such as the climate, geology, stream
gradient, and drainage area of a stream, are typically unchanged by human activities. Other
factors, however, such as the supply and transport of sediment, the character of riparian
vegetation, and the volume and timing of water runoff can be influenced by land-use
activities. These factors all influence the channel morphology and dictate the quality and
quantity of habitat available for aquatic-dependent species. Studying channel morphology
can thus provide a measure of changes in habitat conditions and together with the Aquatic
Life module can help to assess the health of the aquatic system.
Evaluating the effect of land-use activities on channel conditions can be difficult because
stream channels are affected by the interaction of many watershed processes that often have
a great deal of natural variability. Large-scale projects such as dams or levees may create
easily observed impacts on flood discharge and floodplain characteristics but may also have
more subtle long-term impacts on important factors such as sediment storage, channel bed
elevation, and nutrient transport. A great deal of field data collection and analysis may be
necessary to provide evidence that land management impacts, and not natural disturbances
such as floods, are responsible for a change in channel conditions. The Channel analyst
will need to work closely with other analysts, particularly from the Erosion, Vegetation,
Aquatic Life, and Water Quality modules, to conduct a comprehensive assessment.
The objectives for a Level 1 assessment are to characterize the types of channels that
occur within the watershed and to identify where changes in channel morphology are
most prevalent. The Level 1 assessment relies primarily on the analysis of topography,
geology, and soil maps together with a historical set of aerial photographs. Some fieldwork
is encouraged to verify channel characteristics observed on maps and photographs.
Information on channel types within the watershed can be used to develop hypotheses
about the cause of observed channel changes and potential future effects. Further
evaluation and data will be necessary to provide evidence for any cause-and-effect
relationships.
Level 2 methods and tools require specialized expertise and experience in evaluating
channel behavior, conducting field surveys, and interpreting channel-related data. A
Level 2 assessment may be necessary when multiple land uses are impacting the channel
Channel CH-1
-------
or when a defensible, quantitative analysis is required. Potential field methods include
cross-sectional surveys to evaluate channel width/depth ratios, bankfull flows, hydraulic
roughness, and substrate characteristics. More advanced and long-term evaluations may
also involve measurement of discharge, bedload transport, and fine sediment transport.
Analysis techniques can include sediment budgets, stream power calculations, and use of
sediment transport equations and models.
CH-2 Channel
-------
Channel Module Reference Table
Critical Questions
Information
Requirements
Level 1
Methods/Tools
Level 2
Methods/Tools
C1:
How does the physical setting of
the watershed influence channel
morphology?
C2:
How does climate and the fre-
quency, magnitude, duration, and
timing of floods affect channel
conditions?
C3:
How and where has the behavior
of the channel changed over time?
C4:
How and where have changes in
sediment inputs (erosion) over
time affected channel conditions?
C5:
How and where have changes in
riparian vegetation influenced
channel conditions?
C6:
How and where have changes in
stream discharge influenced chan-
nel conditions?
C7:
What are the sediment transport
characteristics of streams in the
watershed?
C8:
Where does sediment storage
occur in the channel and on the
floodplain, and how much sedi-
ment is stored?
C9:
How and where has the dredging,
straightening or shifting of
streams affected channel behavior?
C10:
How does the presence and man-
agement of dams and levees affect
channel conditions?
C11:
What is the potential for change
in channel conditions based on
geomorphic characteristics?
• Air photos
• Topography maps
• Geology maps
• Annual peak flow data
• Climate data
• Historical set of air photos
• Historical set of air photos
• Historical set of air photos
• Sediment source data
• Historical set of air photos
• Riparian vegetation data
• Streamflow data
• Historical set of air photos
• Water withdrawal data
• Sediment transport data
• Streamflow data
• Aerial photographs
• Historical set of air photos
• Streamflow data
• Historical set of air photos
• Air photos
• Topography maps
• Geology maps
• Anecdotal information
• Observations from maps and
air photos
• Existing channel classification
• Existing survey data
• General channel typing
• Anecdotal information
• Air photo observations
• General channel typing
• Anecdotal information
• Air photo observations
• Anecdotal information
• Air photo observations
• Anecdotal information
• Air photo observations
• Anecdotal information
• Air photo observations
• Hydrology data
• Anecdotal information
• Air photo observations
• Anecdotal information
• Air photo observations
• Observations from maps and
air photos
• Existing channel classification
• General channel typing
• Field surveys
• Channel classification
• Geomorphic channel typing
• Field surveys
• Channel classification
• Geomorphic channel typing
• Flood analysis (Hydrology)
• Field surveys
• Channel classification
• Geomorphic channel typing
• Field surveys
• Sediment budget
• Soil Creep Estimation
• Field surveys
• Streamflow models (Hydrology)
• Bank erosion analysis (Erosion)
• Suspended or bedload transport
data
• Sediment transport equations
• Sediment budget (Erosion)
• Field surveys
• Aerial photograph analysis
• Sediment budget (Erosion)
• Field surveys
• Sediment budget (Erosion)
• Reservoir models
• Sediment transport models
• Channel classification
• Geomorphic channel typing
• Field surveys
Channel
page
CH-3
-------
page
CH-4
Channel
-------
Level 1 Assessment
Step Chart
Data Requirements
Topographic maps (1:24,000 scale [7-5-minute
series] or finer preferred).
Aerial photographs (1:12,000 scale preferred).
Photographs recording major storm events and
changes in land use activities are particularly useful
for assessing changes in channel conditions.
Geomorphic maps (if available).
Landform map and erosion data (coordinate with
Erosion module, if applicable).
Land use map (as necessary).
Climate and streamflow information (coordinate
with Hydrology module).
Information on water use/extraction and dam
management (coordinate with Hydrology module).
Delineate Channel Segments
Interpret Channel Sensitivity
Define Geomorphic Channel Types
Products
• FormCl. Historical channel changes
• Form C2. Geomorphic channel type characteristics
• Map Cl. Channel segments
• Map C2. Geomorphic channel types
• Channel report
Procedure
Step 1. Delineate channel segments
Dividing the stream network into segments provides an initial interpretation of channel
character that integrates the landform (i.e., geology, soils, and topography) and fluvial
features of the valley with channel relief, pattern, shape, and dimension. A channel
segment defines a portion of the stream network with relatively uniform channel features.
Channel
page
CH-5
-------
Using aerial photographs, topographic maps, and geology or soil maps, divide the stream
network into segments by identifying locations where the channel characteristics change.
Channel segments provide a preliminary classification system and serve as a reference
for cataloging data and other observations. Characteristics that can be used to delineate
segments include the following:
page
CH-6
Fault locations, major geologic structures, or changes in surface rock types.
Inflow of major tributaries.
Engineering structures, such as dams, diversions, levees, or single conveyance channels.
Local variation in channel pattern.
Channel confinement.
Channel gradient (Box 1).
Box 1. Creating a Longitudinal Stream Profile
A relatively simple analysis of stream gradient can provide useful information for channel
classification and highlight stream reaches that may require further study. Using a
topographic map, determine the stream gradient at regular intervals for the entire length
of the stream. Stream gradient is defined as the change in elevation divided by the
length of the stream reach. Most streams have a generally increasing trend in slope as
measured from the mouth of the stream to its headwaters. Abrupt increases in slope
typically signify areas of higher stream energy and may indicate a change in
confinement, geology, or sediment transport characteristics. Abrupt decreases in slope
typically signify areas of lower stream energy and often correspond to areas of increased
sediment deposition, broader floodplains, and greater stream meandering.
Longitudinal Profile for Bear Creek, Wyoming
12
V
'o
E
BJ
v
£
10 •
8 •
6 •
2 •
Lower gradient may indicate
sediment deposition and more
meandering or bank erosion
Higher gradient may indicate
different channel form or
stream bed character
10 15 20
River Kilometer
30
Channel
-------
• Changes in riparian vegetation.
• The presence, size, or shape of floodplains, terraces, fans, or sand/gravel bars.
Delineate channel segments on a topographic map to create Map Cl (Figure 1). In large
watersheds with numerous tributaries, it may be useful to assign a numeric code to the
mainstem channel and an alphanumeric code (e.g., Al) to each tributary system.
Figure 1. Sample Map C1
Toll River Watershed
Response Segments
The length and number of channel segments will depend upon the watershed size and the
goals of the Watershed Assessment. The analyst should not commit too much time to
examining minor differences in channel character because more data will be collected to
refine the channel classification.
Existing channel classification systems can also be used to delineate channel segments.
Numerous classification systems exist that use one or more parameters to divide
the channel network (Figures 2 and 3) (Graf and Randall 1997; Montgomery and
Buffmgton 1993; Rosgen 1994; WFPB 1997). In most cases, the analyst will want
to use the classification system that is most widely applied in the region. The
Channel
page
CH-7
-------
Figure 2. Watershed map illustrating application of stream
classification based on stream gradient and morphology
(Montgomery and Buffington 1993)
CO
CO
CO
CO
-f -/--
CA
CO = Colluvial
CA = Cascade
SP = Step-Pool
PR = Pool-Riffle
R = Riffle
f = forced by large wood
analyst should, however, evaluate the
utility of using available classification
systems to meet the WAM project goals.
Considerations may include scale of
investigation, available data, and the
need for field data.
Step 2. Assess historical channel
changes
A wide variety of historical data
are useful for reconstructing past
channel changes. In most cases, aerial
photographs will provide the primary
source of historical data. Photographic
coverage that spans decades and records
major events (e.g., floods, catastrophic
events) is necessary to determine trends
in channel conditions through time.
The historical analysis is also the
first step in developing hypotheses
about channel response to management
activities.
Historical changes and trends in
channel attributes provide an important context within which to assess current and
potential channel conditions. Aerial photograph analysis is an efficient method for
focusing field efforts, as well as a valuable resource for indicating historical channel change
and response.
Changes in channel morphology may involve the following elements:
• Engineering structures (diversions, levees, etc.).
• Channel pattern (e.g., sinuosity, braiding).
• Channel width.
• Size and form of sand/gravel bars.
• Extent and frequency of bank erosion.
page
CH-8
Channel
-------
Figure 3a. Stream types: gradient, cross section, plan view (Rosgen 1994)
Figure 3b. Cross-sectional view of stream types (Rosgen 1994)
Dominant
Bed
Material
A
B
D
DA
2
BOULUtfl
3
COQBLE
?^3^
6
SILTfCLAY
ENTRH.
SIN.
W/D
SLOPE
.04-.099
1.4-2.2
.02-.039
>2.2
<.02
N/A
>40
1.1-1.6
<40
<.005
>2.2
<.02
•=.02
.02-.039
Channel
page
CH-9
-------
Areal extent and stability of floodplains, terraces, and fans.
Scour from floods or channelized landslides.
Wood debris loading.
Canopy opening or changes in vegetation patterns.
Sediment processes (local storage or erosion).
Road crossings.
Hydrology
Reference points (i.e., fixed landmarks) should be identified so changes in channel
dimensions and forms can be measured in successive aerial photographs. Measuring the
same cross-sectional area (transect) allows the Channel analyst to compare changes in
channel width and area over time. Measurements from different sets of aerial photographs
will need to be corrected to account for scale differences and distortion. For small
channels, direct observation of channel width may not be possible due to dense riparian
vegetation. For these channels, canopy opening provides a useful surrogate for channel
width (Grant 1988). In larger channels, changes in gravel bar size and vegetation cover
may also be observed over time. To correlate channel changes with floods, coordinate
with the Hydrology analyst. Where historical changes are observed, record observation
on Form Cl (Figure 4).
Figure 4. Sample Form C1. Historical channel changes
Channel
segment(s)
Historical changes
Other observations
Channelized with con-
crete banks since 1903
Radical changes have virtually eliminated
aquatic habitat. Concrete channel minimizes
influence of sediment, water, and vegetation.
2,6
Levees since pre-1900
Dirt levees minimize sediment deposition.
Flood scour compromises levee integrity.
3,7, 11, 12, 13
Possible increased
entrenchment
Interviews and aerial photos indicate channel
incision over past 50 years, possibly due to
removal of in-stream wood debris and
increased runoff from urbanization.
4,5,9, 10
Increased sediment
deposition and bank
erosion
Low-gradient section with natural tendency for
sediment storage and channel migration. Ero-
sion from agricultural lands, grazing, and veg-
etation removal has probably increased sedi-
ment supply.
page
CH-10
Channel
-------
Step 3: Interpret channel responsiveness
Change
Potential Channel Responses
Increasing water runoff
Entrenchment (incision)
Gully formation
Coarsening of stream bed (i.e., less fine sediment)
Increased bank erosion
Decreasing water runoff
Aggradation
Increased fine sediment in the stream bed
Decrease in channel width
Understanding the factors that control and influence channel processes is critical to the
Synthesis step of the WAM process. The potential response of each channel segment to
changes in sediment, water runoff, and vegetation will need to be evaluated in the context
of historical channel behavior and the natural geomorphic setting (e.g., geology, gradient,
valley confinement). Table 1 lists possible channel responses. The exact nature and
duration of the responses will vary depending on the watershed and channel characteristics
and the causes for the changes.
Table 1. Examples of potential channel responses to changes
in water runoff, sediment supply, or vegetation
Considering evidence from
aerial photographs, stream
surveys, watershed reports,
anecdotal information, and
observations, identify channel
segments that have shown a
significant response to floods,
vegetation disturbance, or
changes in sediment supply
(Figure 5). A change in channel
behavior from natural or human
disturbances generally signifies
the potential for future changes
at these channel segments.
Consult with the Hydrology,
Erosion, and Vegetation analysts
to help correlate channel
changes with large floods,
periods of increased erosion, or
substantial changes to upland
or riparian vegetation. The
analysts can provide useful information on the magnitude, frequency, distribution,
and timing of changes in these watershed processes. The Historical Conditions and
Community Resource analysts may also have useful information on past conditions
or historical practices in and around the channel. Hypothesized connections between
historical practices and changes in channel conditions will often require further Level 2
assessment to provide evidence for causal links.
Increasing sediment
supply
• Aggradation
• Larger, more frequent sand and gravel bars
• Increased fine sediment in the stream bed
• Increased channel movement
• Increased flooding
Removal of upland
vegetation
Increased flooding
Increased sediment delivery
Removal of riparian
vegetation
Increased bank erosion
Aggradation
Fining of the stream bed
Increased channel movement
Channel widening
Hydrology
Erosion
Vegetation
Historical
Conditions
Community
Resources
Channel
page
CH-11
-------
Figure 5. Examples of channel form as a function of gradient, particle size, and sediment supply
Low -*-
Fine •*-
Dominant textures of floodplain sediments
Coarse
Tortuous meanders
gi
±
5
ra
»
0
\
I
Low
CTl
±
•o
2
01
Ratio of Bed-material load to total sediment load
-"High
Adapted from Selby (1985)
In addition to considering external agents for channel changes, it will be important to
consider the geomorphic setting of the channel to help evaluate where a high potential for
change exists naturally. A longitudinal stream profile will often help to identify segments
where a shift in gradient will increase the potential responsiveness of the channel. Evaluate
whether changes in geology or soil type correlate with a change in channel pattern or
behavior. Finally, examine the correlation between segments with a natural potential for
responsiveness and evidence of historical changes in channel behavior. These correlations
can be used to identify other channel segments with a high potential for responsiveness,
even if these segments have not changed significantly in recent times.
Information on changes in channel behavior will be used in the following step to help
define geomorphic channel types and to rate the responsiveness of channel types to changes
in sediment, water runoff, vegetation, and other disturbances.
Step 4. Define geomorphic channel types
Defining geomorphic channel types relies on the work conducted in the previous steps, as
well as products from other modules. Geomorphic channel types are groups of segments
that have similar characteristics and that are expected to respond similarly to changes in
page
CH-12
Channel
-------
water runoff, sediment, and vegetation. Channel typing can be useful to help integrate
information on hillslope processes with information on channel conditions to ultimately
assess aquatic habitat sensitivities.
Erosion
Hydrology
Vegetation
Specific criteria for developing channel types do not exist, so the Channel analyst must
use available data and professional judgment to define appropriate categories. Channel
types should consider both stream and valley form to characterize segments with similar
geomorphic responsiveness. Group segments with similar channel conditions and potential
responses to altered water runoff, sediment supply, or vegetation or to natural disturbances
(e.g., floods, hurricanes, fire). Existing channel classification schemes (Graf and Randall
1997; Montgomery and Buffmgton 1993; Rosgen 1994; WFPB 1997) often consider
many of these factors. A geomorphic channel type will typically consist of a group of
channel segments, but a unique segment may warrant its own channel type. It may be
helpful to consult with the Erosion analyst for a further understanding of the land types
present in the watershed. Although the channel types are likely to be related to geomorphic
land types, their delineation may not directly coincide.
Erosion
Creating geomorphic channel types provides a way of organizing information from the
Channel module and other modules to describe linkages between hillslope processes and
aquatic resources. Identification of channel types may involve some generalization such
that some local reaches may not have the same response potentials as other reaches of the
same type (WFPB 1997). Prior to the start of Synthesis, the Channel analyst should work
with the other module analysts to interpret potential linkages between land use practices,
changes in watershed processes, and channel responses.
Erosion
Hydrology .
Vegetation r
Aquatic Life
Identify geomorphic channel types on Map C2 (Figure 6). Form C2 can be used to
describe each channel type and summarize the hypothesized responsiveness of each channel
type (Figure 7). Responsiveness for each channel type should be rated "High," "Moderate,"
or "Low" relative to changes expected in other channel types. Since the response potential
of each channel type is based primarily on remote analysis of maps and other data, ratings
should be considered preliminary. Field verification and further analysis will often be
necessary to provide support for responsiveness ratings.
Step 5. Produce Channel report
The analyst should produce a report that organizes and presents the methods, data, and
results of the Channel assessment. The report should include a brief narrative along with
Channel
page
CH-13
-------
Figure 6. Toll watershed geomorphic channel types
(adapted from Washington Forest Practices Board 1997)
0 Mainstem Tolt
^ South Fork below the reservoir
Q] Reservoir and Tributaries
North Fork above ??
Qj North Fork canyon
South Fork canyon
1 I Tributaries to the
Middle North Fork
Steep Tributaries draining
convergent topography
North Fork braided chutes
tables, graphs, forms, and maps to provide the scientific justification for channel typing and
responsiveness ratings. The type of data or information necessary for a high confidence
level in the analyses and interpretations will not always be available; therefore, the analyst
must address the confidence level of the data and work products. The degree of confidence
that can be assigned to the products depends upon a number of factors:
• The amount, type, and quality of available information.
• The relative confidence for each work product.
• The extent of field work.
• The experience of the analyst.
• The complexity of the geology and terrain.
• Aerial photograph and map quality.
• Multiple lines of evidence for inferred changes.
page
CH-14
Channel
-------
Figure 7. Sample Form C2. Geomorphic channel type characteristics
1*113111161
type
Lower
Confined
Mainstem
Entrenched
Mainstem
Tributaries
on River
Floodplain
Tributaries
in Naches
Formation
Meandering
Upper
Mainstem
Description
Low gradient (<1%),
broad historic flood-
plain, islands, river
confined by levees
Low gradient (<1%),
recent channel
entrenchment
Low gradient (<2%),
small meandering
and braided streams,
wetlands, and old
oxbows common
2-4% gradient,
entrenched, with
high, raw banks in
weak sandstone
2-6% gradient, gravel
and cobble substrate,
numerous rapids
wnannei
segments
1 and 2
3
A1.B1,
and C1
A2, A3,
C2, and
D1
4-8
Potential responsiveness rating
Sediment
Moderate
Low
High
Low
Moderate
Runoff
High
Moderate
Low
High
Low
Vegetation
Moderate
Low
High
High
Moderate
Evidence supporting rating
• Floods in 1980s undermined levees
• Rip-rap instead of trees maintain
river banks
• Wetlands historically provided
flood water storage
• Historical floodplain not inundated
during floods
• Substantial bank erosion, but no
change in pattern following floods
in 1980s
• Increased sediment supply could
cause sub-surface flow
• Root system from riparian trees
maintain streambanks
• Runoff spreads across floodplain
• Floods cause severe bank erosion
• Wood debris important for storing
sediment
• Sediment not a problem, but more
fine particles could change sub-
strate character
• Trees important for shade and
bank stability
Channel
page
CH-15
-------
Level 2 Assessment
Stream channels are formed by a complex set of physical processes. Interpretations of
channel conditions can be difficult because of the dynamic interactions among climate,
water flow, and sediment transport. Determining natural or historical conditions is often
a challenge because many streams have been significantly modified by human activities.
Understanding the natural disturbance history can also be important for understanding
current conditions. Evidence of channel disturbance from floods, landslides, or fires
is often observable in channel and floodplain deposits for many decades following the
disturbance.
Because of the complexity of channel processes, parameters used to assess stream
conditions should be established in the scientific literature so that observations can be
credibly supported. Parameters should focus on geomorphic forces that can be quantified
(e.g., channel gradient, substrate size, shear stress) so that the analysis is repeatable and
changes can be reliably measured. Ideally, parameters will be applicable to a wide range
of channel types and account for variability from reach to reach. While some channel
variables require long-term monitoring data, many useful parameters are relatively easy
and inexpensive to measure in the field or from remote sensing.
The Level 2 assessment is divided into three general approaches to channel investigation:
1. Stream channel surveys.
2. Detailed channel classification.
3- Sediment budgets.
The following sections do not provide detailed instructions but offer general guidelines
and references to other sources that elaborate on these procedures. The following books
provide general information about channel processes and ways to evaluate them:
• Rivers: Form and Process in Alluvial Channels (Richards 1982).
• Water in Environmental Planning (Dunne and Leopold 1977).
• The Fluvial System (Schumm 1977).
• Drainage Basin Form and Process (Gregory and Walling 1973).
• Fluvial Processes in Geomorphology (Leopold et al. 1964).
CH-16 Channel
-------
Stream Channel Surveys
Field surveys are a critical element of any analysis of stream channel conditions. Fieldwork
provides quantitative data on stream conditions that ideally can be extrapolated to evaluate
conditions at a watershed scale. Field surveys can help with the following:
• Characterizing variation in channel features.
• Evaluating channel types.
• Applying or verifying channel classification schemes.
• Clarifying observations from maps and aerial photographs.
• Establishing reference sites to monitor changes in channel condition.
The number and location of surveys will vary depending on the objectives of the
assessment and available time and resources. Where measurements are to be used for
flow or sediment transport calculations, sites should be straight, single-stranded, and
unobstructed to minimize complications. Where measurements will be used to compare
conditions between streams, it will be important that characteristics such as gradient,
substrate, and channel form are similar so that the effects of land management can be
better isolated. Measurements for baseline and trend monitoring should be located in areas
where change is likely and will be visible. In general, locally dynamic sites such as tributary
confluences or alluvial fans should be avoided.
The following sections provide a brief description of techniques for examining channel
variables. Detailed instructions on conducting stream surveys can be found in the
following sources:
• Stream Channel Reference Sites: An Illustrated Guide to Field Technique (Harrelson et al.
1994).
• Survey Methods for Ecosystem Management (Myers and Shelton 1980).
• Timber-Fish-Wildlife (TFW) Monitoring Program Method Manual for the Reference Point
Survey (Pleus and Schuett-Hames 1998).
Longitudinal and cross-sectional stream surveys
A stream reach can be characterized using a combination of longitudinal and cross-sectional
surveys. The surveys should include a plan-view sketch of the stream reach and detailed
Channel CH-17
-------
Box 2. XSPRO for cross-sectional data
notes on channel characteristics to help identify important benchmarks and measurement
points. A surveyor's level and rod along with fiberglass tape can be used to map
the location and elevation of important channel features. Channel features can
include the stream gradient, bankfull width, bankfull depth, and floodplain features.
Data on stream substrate, sediment particle size,
and hydraulic roughness can also be collected
at cross-sectional survey points (Box 2). The
following paragraphs provide more information
on measuring specific channel features.
XSPRO is a USFS computer program designed for use
by specialists and non-specialists alike to calculate
hydraulic parameters based on cross-sectional surveys
(Grant et al. 1992). The program accepts x- and y-coor-
dinates from the cross-sectional survey along with depth
of flow (either observed or inferred) and calculates a ser-
ies of hydraulic parameters, including shear stress and
stream power. The program produces both graphical
and tabular outputs. XSPRO is available free of charge
and is relatively easy to use. It is available from West
Consultants at http://www.westconsultants.com.
Channel width and depth
The most useful measure of channel width
and depth is at bankfull flow because this
discharge is morphologically definable in the
field and typically has the greatest control on
the dimensions of alluvial channels over time
(Leopold et al. 1964). Bankfull flow is generally
reached once every two years (Dunne and
Leopold 1977). Bankfull width and depth refer to the width and average depth of
the channel at bankfull flow. While the boundaries of the bankfull channel can be
difficult to consistently identify, the edge of the bankfull channel usually corresponds
to the start of the floodplain (Figure 8). The floodplain is defined as the generally flat
landscape feature adjacent to most channels that is overflowed at times of high discharge
(Dunne and Leopold 1977). The start of the floodplain is often characterized by the
following features:
• A berm or other break in slope from the channel bank to a flat valley bottom, terrace,
or bench.
• A change in vegetation from bare surfaces or annual water-tolerant species to perennial
upland or water-tolerant shrubs and trees.
• A change in the size distribution of surface sediments (e.g., gravel to fine sand).
Bankfull width and depth data are necessary for analysis of channel characteristics
including the cross-sectional area, width to depth ratio, bed shear, and stream power.
Benson and Dalrymple (1967) describe measurement methods in more detail.
page
CH-18
Channel
-------
Figure 8. Indicators for determining bankfull width
Floodplain
Bank Shape
Soil ' •;•• •-
Indicators:
1. Floodplain
2. Bank Morphology
and Composition
3. Vegetation
Best indicators on this bank
Adapted from Pleus and Schuett-Hames (1998)
Hydraulic roughness
Hydraulic roughness is a critical part of basic hydraulic calculations because it addresses a
loss of energy from turbulence. Less energy to move water and sediment has important
implications for water discharge, sediment transport, and erosion rates. The elements of
roughness, including particle size, form roughness (e.g., dunes and riffles), and vegetation
roughness, can change under natural circumstances or by human intervention. Roughness
due to vegetation may also change seasonally.
Manning's n is the most commonly used roughness parameter and is derived from
Manning's Equation to calculate stream flow velocity:
V=(l/n)(R2/3)(S1/2)
Where: V = velocity (ms"1), n = hydraulic roughness (dimensionless), R = hydraulic
radius of the channel (the area of the channel divided by the length of the wetted
perimeter) (m), and S = channel slope or gradient.
Manning's n cannot be directly measured but can be estimated if the other variables
in the flow equation are known. Estimates of Manning's n have been developed for
Channel
page
CH-19
-------
a broad range of natural and artificial channels. Tabulated values or photographs
of representative stream reaches of known roughness can provide useful estimates of
hydraulic roughness (Cowan 1956; Chow 1959; Barnes 1967)- Estimates of hydraulic
roughness on floodplains (Arcement and Schneider 1989) and in dryland streams
(Aldridge and Garrett 1973) are also available to provide examples from different regions.
Limerinos (1970) provides guidance on calculating roughness from field surveys of the
channel bed.
Channel gradient
The gradient of the channel has a direct influence on the velocity of flow and the ability
to entrain and carry sediment. The general channel gradient can be estimated from
topographic maps, but local gradient changes will not be detected by this approach.
Accurately measuring the gradient of the water surface (typically based on estimated
bankfull elevation) with a level or transit is important for site-specific evaluations of
stream discharge and sediment transport.
Substrate size and distribution
Determining the size and distribution of streambed substrate can provide information
on roughness elements and aquatic habitat types. Streambed particle sizes can also be
important for evaluating channel stability following disturbances (e.g., regulated dam
releases or construction projects on the floodplain).
Classification of substrate type is an easy qualitative descriptor of the channel bed.
Categories of substrate size typically include clay, silt, sand, gravel, cobble, and boulder
Table 2. Substrate size categories (Table 2). Finer gradations of each particle size such as coarse,
medium, or fine may be useful to provide greater detail on the
substrate character.
Two quantitative methods for characterizing streambed particle
size are sieve analysis and the relatively easy Wolman's method of
pebble counts (Wolman 1954; Potyandy and Hardy 1994). For
either method, a sample of particles is measured at cross-sections
of the channel bed or bar. A sieve analysis simply involves filtering
a sediment sample through various sieves to characterize the range
of particle sizes. The Wolman pebble count relies on measurements from a sample of
surface sediments. To create a representative sample, the median diameter of each particle
Substrate
Clay
Silt
Sand
Gravel
Cobble
Boulder
Size Range (mm)
<0.0039
0.0039-0.0625
0.0625-2.0
2.0-64.0
64.0-256.0
256.0-4096.0
page
CH-20
Channel
-------
touched by the toe of one foot is measured at every step or series of steps in several
passes across the channel. A sample size of at least 100 particles is usually necessary
to conduct simple statistical analyses. Reid and Dunne (1996) provide a more detailed
discussion of the location and number of samples necessary to characterize substrate. With
either method, a frequency distribution is usually created to identify the mean or median
diameter (D ) and the diameter at two standard deviations from the mean (Dlg and D84)-
Several cross-sections should be evaluated in a reach to determine the general character of
the streambed. Harrelson et al. (1994) provides a good description of how to characterize
bed and bank materials.
Quantitative analysis of cross-section data
Width to depth ratios
Monitoring changes in channel dimensions can be a useful method for identifying and
evaluating trends in channel conditions. One of the simplest comparisons is a width to
depth ratio. The depth can be either the average or maximum bankfull depth. Changes
in the ratio over time or space are usually indicative of differences in water discharge or
sediment transport capacity. Care must be taken to differentiate changes due to episodic
events such as flooding from long-term watershed changes such as increased water or
sediment supply from urbanization.
Water velocity and discharge
Calculating discharge is a function of the channel area and the velocity of the water. Stream
discharge data can usually be obtained from the Hydrology module, although more site-
specific estimates may be necessary for stream power and sediment transport analysis. ^ Hydrology
Locally developed empirical equations are a common tool for estimating discharge.
Equations to estimate flood flows have been developed throughout the United States and
are relatively easy to apply. Most equations are based on a regression analysis of existing
discharge data and are generally a function of the basin area, precipitation, and vegetative
cover. The length of streamflow records and the uniformity of the landscape are important
to consider in evaluating the accuracy of these predictions.
More accurate site-specific discharge measurements can also be obtained from cross-
sectional survey measurements. A number of software packages, such as XSPRO (Box 2),
can be used to help estimate discharge using Manning's or other equations. More intensive
field methods for calculating discharge generally fall into four categories:
Channel CH-21
-------
• Volumetric measurement (generally appropriate only for small streams).
• Measurement of stream velocity and cross-sectional area.
• Dilution gauging using a salt or dye.
• Artificial controls such as weirs, with known stage-discharge relationships.
Further information on techniques for measuring velocity and stream discharge can be
found in Corbett (1962) and Herschy (1985).
Stream power
Stream power is a measure of the stream's capacity to move sediment over time. Stream
power can be used to evaluate the longitudinal profile, channel pattern, bed form
development, and sediment transport of streams. It may be measured for an entire stream
length or stream reach or per unit of channel bed area. The general form of the stream
power equation is as follows:
" = pgQ?
Where: £1 = stream power, p = density of water; g = gravitational acceleration;
Q= water discharge; and s = slope.
A general evaluation of power for an entire stream or a particular reach can be calculated
using the average discharge and average valley or channel slope for the given length.
Measurements of stream power per unit of bed area provide a more accurate assessment
of the stream's ability to move material because frictional losses of energy are accounted
for in the equation.
In addition to measurements of discharge and channel slope at a cross-section, a measure
of shear stress (l) needs to be calculated. Shear stress may be described as the drag
exerted by the flowing water on bed sediments and the channel perimeter. Shear stress
is defined as follows:
T = pgRs
The actual amount of work accomplished by the stream per unit of bed area depends
upon the available power divided by the resistance offered by the channel sediment,
forms, and vegetation. The stream power equation can thus be rewritten as follows:
CH-22 Channel
-------
CO = pgRsv = TV
Where: CO = stream power per unit of bed area and v = average water velocity.
Consult the reference books on channels listed at the beginning of the "Level 2 Assessment"
section for further details on calculating stream power and shear stress.
Detailed Channel Classification
As discussed briefly in the Level 1 assessment section, numerous channel classification
systems exist to characterize stream reaches. Classification systems are useful descriptors of
stream behavior and can be applied for extrapolation and prediction. Thus, classification
systems that are based on natural physical processes provide the greatest potential for
accurate predictions. The simplest forms of channel classification rely on stream order
(Strahler 1952) or plan form channel patterns such as sinuosity and braiding intensity
(Brice I960).
Several reviews of fluvial classification systems exist to help evaluate various approaches
(Goodwin 1999; Thome 1997; Downs 1995; Naiman et al. 1992). A brief list and
description of reach-scale stream classification systems follows:
• Leopold and Wolman (1957): A simple three-part division of river patterns into braided,
meandering, and straight.
• Kellerhals et al. (1976): A more complex system based on a combination of channel
pattern, islands, channel bars, and major bedforms.
• Rosgen (1994): A hierarchical system with eight primary stream types based on
dimensional properties of the channel.
• Woolfe and Balzary (1996): A process-oriented approach with eight categories that relate
rates of aggradation/degradation for the channel and floodplain.
• Whiting and Bradley (1993): A process-oriented system, primarily applicable to
headwater areas, with 42 stream classes based on dimensional measures of channel form.
• Montgomery and Buffington (1997): A probabilistic system with seven channel types
based on dimensional and qualitative morphologic characteristics.
• Nanson and Croke (1992): A probabilistic classification of 15 floodplain types based on
both process and form dimensions.
• Miall (1996): An example-based approach with three major classes divided into
16 fluvial styles that are derived from predominantly qualitative morphologic
characteristics.
Channel CH-23
-------
Sediment Budgets
A complete sediment budget considers the sources, storage, and transport of sediment
from a watershed. As described in the Erosion module, evaluation of sediment sources to
streams is often sufficient to evaluate the effects of land management activities. However,
where it is important to understand the fate of sediment once it enters the stream
channel, the storage and transport of sediment will need to be investigated.
The transport, deposition, and storage of sediment can be very complex, with impacts
at sites far removed from the original sediment inputs. Prior to conducting a
detailed analytical assessment, a qualitative evaluation of channel conditions from aerial
photographs and field observations will help to focus the analysis on areas of the
stream network that have been most responsive to changes in sediment or flow inputs.
Depending on the identified watershed issues, it may also be possible to focus on just
coarse or fine sediment yield and transport. Identifying trends in channel conditions and
predicting channel response can often be accomplished by a combination of qualitative
observations and quantitative analysis with an order of magnitude accuracy.
Close interaction among the Channel, Erosion and Hydrology analysts will typically
be required to develop a useful sediment budget. The Erosion module can provide
qualitative information on geology/soil influences and quantitative estimates of sediment
Erosion ^ inputs. The Hydrology module can provide data on flood history and the factors that
are influencing runoff and stream discharge. Collectively, this information will provide
a good, semi-quantitative, systematic understanding of channel processes and sediment
distribution patterns.
Sediment budgets are particularly useful for assessing water quality and morphologic
channel changes due to altered inputs of sediment or water to streams (Reid and
Dunne 1996). The evaluation of changes typically requires characterizing a channel
under undisturbed conditions and predicting how those characteristics will change with
alterations in sediment or water inputs. Table 3 provides examples of channel issues that
can be evaluated with sediment budget techniques. Aerial photos, field surveys, substrate
analysis techniques, and flow equations have been addressed in previous sections of this
module. Sediment mobility analysis and sediment transport equations are discussed in
the following sections.
CH-24 Channel
-------
Table 3. Examples of channel issues and selected techniques for evaluating
changes in channel conditions (adapted from Reid and Dunne 1996).
Example Questions
How much introduced sediment will be
transported out of the watershed?
What proportion of introduced sediment be
deposited and where will it be deposited?
How will changes in sediment inputs affect
channel form?
How long will it take for the channel to
recover from sediment inputs?
How will altered sediment inputs affect
water quality?
Will a change in flow cause incision or
aggradation?
Where are incision or aggradation likely to
occur?
How fast will a reservoir lose storage
capacity?
Aerial Field Flow Substrate Transport
Photos Surveys Equations Analysis Equations
Sediment mobility analysis
Sediment transport is generally divided into two components: suspended load and bedload.
The suspended load (or washload) is composed of sediment that is fine enough to
be flushed downstream as part of the water column and that does not accumulate in
significant quantities except where overbank flows deposit material on the floodplain. The
bedload consists of the coarser sediment fraction that at least intermittently settles to the
bed during its downstream migration. While a portion of the bedload is suspended at
higher discharges, the distinction between bedload and washload is still appropriate for
most situations during the dominant transporting flows.
Channel
page
CH-25
-------
Bed mobility analysis
The focus of most bed mobility analyses is on which grain sizes can be moved at which
discharges. The traditional method for predicting the initial motion of a bed particle
involves analyzing the effect of the shear stress from flow near the bed on the lift and drag
forces that move a particle out from neighboring grains (Reid and Dunne 1996). This
method, often referred to as Shields' function, yields the following equation for rough
beds with turbulent flow:
Tc = Pgds = 0.06(p-ps)gD
Where: Tc = critical shear stress; p and ps = the density of water and sediment,
respectively; g = gravitational acceleration; d = flow depth; s = water slope; and
D = the diameter of the particle of interest and its neighbors.
Graf (1971) and Richards (1990) provide a good review of the relationship between
particle size and channel geometry, the combination of lift and drag forces, and the
initiation of particle transport. Reid and Dunne (1996) provide a good summary of
empirically derived equations from the scientific literature on initiation of motion for bed
particles. Application of particle entrainment equations requires a strong background in
fluvial geomorphology and understanding of the scientific literature.
Local field observations, however, can provide a general estimate of particle sizes that are
transported during floods and can be a useful check of critical shear stress equations (Reid
and Dunne 1996). Maximum mobile grain size can be estimated by measuring the largest
particles that were obviously rearranged on gravel bars or that were deposited over new
organic debris. Painted rocks and scour chains can also be used as part of a monitoring
program to gather data on bed scour before and after floods.
Suspended load grain size estimates
Determining which particle sizes are suspended at various flows is often the first step in
evaluating sediment transport rates. The magnitude of the settling or fall velocity reflects
a balance between the downward force due to the particle's weight and opposing forces
due to fluid viscosity and inertial effect. Viscous resistance is a dominant force for small
particles in the silt-clay range but is less important for larger particles (Richards 1982).
The suspendibility of a particle is usually defined as follows:
CH-26 Channel
-------
P < w. / u
Where: ws is the settling or fall velocity of the particle, and u* is the shear velocity
of the flow.
The settling velocity and shear velocity can be defined as follows:
ws = 9000 D2 for silts and clays
ws = [0.67 Dg (p-ps)/r]2 for sands and gravels
u* = (T/p)0'5
Dietrich (1982) describes a method for estimating the settling velocity of natural particles.
In the absence of good field data, Komar (1980) provides estimates for suspendibility
based on a review of available data. Most of the data, however, were obtained from
flume experiments or low-gradient, sand-bedded channels and may not be appropriate for
some streams.
Sediment transport
Information on sediment transport rates can be useful for evaluating changes in land
management or flow regimes and for identifying locations of potential aggradation or
degradation. Suspended sediment transport can also be an important factor for evaluating ^ Water
pollutants because many contaminants move through the stream network attached to ua i y
sediment rather than through solution (Horowitz 1991).
Sediment transport rates can be characterized using any combination of field observations,
monitoring data, and predictive equations. The following sections describe methods for
determining sediment transport rates for both suspended load and bedload.
Suspended load
The suspended load often represents the majority of sediment transport but is difficult
to predict because the transport rate depends more on sediment supply than on channel
hydraulics (Reid and Dunne 1996). The primary method for evaluating suspended
sediment transport rates requires data from a sediment sampling program. Suspended
sediment concentrations can then be related to the stream discharge to provide an estimate
Channel CH-27
-------
of transport rates (Figure 9)- Since most sediment transport occurs during floods, it is
essential to have sampling data from periods of high discharge. The USGS publishes
a great deal of suspended sediment and streamflow data, much of which is available at
http: //webserver, cr. usgs. gov/sediment.
Figure 9. The relationship between suspended sediment and discharge data,
Newaukum River, Washington, 1964-1965
8000
7000
"> 6000
BJ
sz,
•£ 5000
^ 4000
"8
-0 3000
V
a.
= 2000
1000
0
(
0 y = 3E-05x2'2511
R2 = 0.9464
-
O o O
00
0
0
o
o
00
0°
^ _ t ° -
) 1000 2000 3000 4000 5000 60(
Water Discharge (cfs)
Long-term suspended load transport rates can also be estimated by comparing the grain
size distribution of sediment inputs with the channel bed composition (Reid and Dunne
1996). The size fraction that is missing from the bed is considered the suspended load.
Multiplying the sediment input rate by the proportion of the missing size fraction would
then provide an estimate of the suspended load.
Bedload
While no definitive bedload transport equation exists, a number of different transport
equations have been developed for sand- and gravel-bedded streams. Data requirements
vary among equations, but most require information on channel gradient, depth, width,
and sediment character. Graf (1971), Vanoni (1975), and Reid and Dunne (1996)
review a number of sediment transport equations and provide further references for
detailed application.
page
CH-28
Channel
-------
Most of the bedload transport equations have a strong empirical basis and are best suited
for conditions similar to those used in the development of the equation. Moreover,
most equations were developed from flume experiments and depend on a number of
assumptions that may limit their extrapolation to natural stream environments. It may
be useful to use a number of different equations to assess the accuracy of the estimates.
A great deal of judgement and experience are necessary to use these types of equations
and to make meaningful interpretations. Some field measurements may be necessary to
verify calculated results.
Sediment storage
Sediment is stored in and released from channels and valley floors over time periods
ranging from days to centuries. The accumulation of sediment may have important
ecological implications and be a significant part of the sediment budget. Dietrich et al.
(1982) provide an overview of sediment storage and estimate residence times for several
types of storage reservoirs, including debris fans, active channel sediment, and floodplain
sediment. Qualitative observations and analysis are often sufficient to assess the influence
of sediment storage on the sediment budget. For example, observations or mapping
of depositional forms and textures (e.g., gravel bars, floodplains) may be adequate to
determine the locations and size fractions of sediment deposition in the watershed or
whether sediment volume is increasing or decreasing.
Trends in aggradation and incision can be estimated from a number of field indicators,
including changes in the riparian community, cross-sectional surveys at stream gage and
bridge locations, or buried structures such as riparian trees, bridge piers, or fence posts.
Studies that have evaluated sediment storage include the following:
• Trimble (1983) evaluates long-term alluvial storage in a Wisconsin basin.
• Kelsey et al. (1987) evaluate sediment reservoirs from a basin in northern California.
• Likens and Bilby (1982) address in-channel sediment and nutrient storage behind logs
in New England streams.
• Laird and Harvey (1986) examine the effects of wildfire on aggradation and incision
in Arizona streams.
• McGuiness et al. (1971) and Matherne and Prestegaard (1988) evaluate seasonal
patterns in sediment storage for basins in Ohio and Pennsylvania, respectively.
• Collins and Dunne (1990) plot low-flow water elevations over time and use channel
cross-section surveys at bridges to show changes in bed elevation from gravel mining.
Channel CH-29
-------
Sediment detained by lakes or reservoirs also provides an opportunity to estimate
sediment transport and storage. Griffen (1979) reviews methods for determining trap
efficiencies in large reservoirs. Heinemann (1981), Moglen and McCuen (1988), and
Dendy and Champion (1978) provide methods and data for evaluating the trap efficiency
of small reservoirs and detention basins.
page
CH-30
Channel
-------
References
Arcement, G. ]., Jr., and V. R. Schneider. 1989- Guide for selecting Manning's roughness
coefficients for natural channels and flood plains. U.S. Geological Survey, Water-
Supply Paper 2339, Washington, D.C.
Aldridge, B. N., and J. M. Garrett. 1973- Roughness coefficients for stream channels in
Arizona. U.S. Geological Survey Report, in cooperation with Arizona Highway
Department.
Barnes, H. H., Jr. 1967- Roughness characteristics of natural channels. U.S. Geological
Survey, Water-Supply Paper 1849, Washington, D.C.
Benson, M. A., andT. Dalrymple. 1967- General field and office procedures for indirect
discharge measurements. Techniques of Water-Resources Investigations of the
U.S. Geological Survey. Book 3, Chapter Al. pp. 1-30. U.S. Geological Survey,
Washington, D.C.
Brice, J. C. I960. Index for description of braiding. Bulletin of the Geological Society
of America 71:1833-
Chow, V. T. 1959- Open-channel hydraulics. McGraw Hill, New York, New York.
Collins, B. D., andT. Dunne. 1990. Assessing the effects of gravel harvesting on sediment
transport and channel morphology: A guide for planners. State of California
Division of Mines and Geology, Sacramento, California.
Corbett, D. M. 1962. Stream-gaging procedure. U.S. Geological Survey, Water-Supply
Paper 888, Washington, DC.
Cowan, W L. 1956. Estimating hydraulic roughness coefficients. Agricultural
Engineering 37:473-475-
Dendy, E E., and W A. Champion. 1978. Sediment deposition in U.S. reservoirs.
Summary of data reported through 1975- U.S. Department of Agriculture,
Miscellaneous Publication 1362, Washington, D.C.
Channel CH-31
-------
Dietrich, W. E. 1982. Settling velocity of natural particles. Water Resources Research
18:1615-1626.
Dietrich, W. E., T. Dunne, N. E Humphrey, and L. M. Reid. 1982. Construction of
sediment budgets for drainage basins. Pp 5-23 in: E J. Swanson, et al. (eds.).
Sediment budgets and routing in forested drainage basins. U.S. Department
of Agriculture Forest Service, General Technical Report PNW-141, Portland,
Oregon.
Downs, P. W. 1995- River channel classification for channel management purposes. , Pp.
347-365 in: A. Gurnell and G. Petts (eds.). Changing river channels. John Wiley
and Sons, Chichester, England.
Dunne, T., and L. B. Leopold. 1977- Water in environmental planning. WH. Freeman and
Company, New York, New York.
Goodwin, C. N. 1999- Fluvial classification: Neanderthal necessity or needless normalcy?
Wildland Hydrology, American Water Resources Association, June/July:229-236.
Graf, W H. 1971. Hydraulics of sediment transport. McGraw-Hill, New York, New York.
Graf, W L., and K. Randall. 1997- The physical integrity of Arizona streams: A guidance
document for river management. Draft report prepared for Arizona Department of
Environmental Quality, Contract 95-0137-
Grant, G. 1988. The RAPID technique: a new method for evaluating downstream effects
of forest practices on riparian zones. U.S. Department of Agriculture Forest
Service, General Technical Report PNW-GTR-220, Portland, Oregon.
Grant, G. E., J. E Duval, G. J. Koerper, and J. L. Fogg. 1992. XSPRO: A channel
cross-section analyzer. U.S. Department of Interior, Technical Note 387, Denver,
Colorado.
Gregory, K. J., and D. E. Walling. 1973- Drainage basin form and process. Wiley, New
York, New York.
Griffen, D. M., Jr. 1979- Reservoir trap efficiency: The state of the art. Journal of Civil
Engineering Design l(4):355-377-
page
CH-32 Channel
-------
Harrelson, C. C., C. L. Rawlins, and J. P. Ptoyondy. 1994. Stream channel reference sites:
An illustrated guide to field technique. U.S. Department of Agriculture Forest
Service, General Technical Report RM-245, Fort Collins, Colorado.
Heinemann, H. G. 1981. A new sediment trap efficiency curve for small reservoirs. Water
Resources Bulletin 17(5).
Herschy, R. W. 1985- Streamflow measurement. Elsevier Applied Science, London.
Horowitz, A. J. 1991. A primer on sediment-trace element chemistry. Lewis Publishers,
Chelsa, Michigan.
Kellerhals, R., M. Church, and D. I. Bray. 1976. Classification and analysis of river
processes. Journal of Hydraulics Division 102:813-829-
Kelsey, H. M., R. Lamberson, and M. A. Madej. 1987- Stochastic model for the long-term
transport rate of stored sediment in a river channel. Water Resources Research
23(9):1738-1750.
Komar, P. D. 1980. Models of sediment transport in channelized water flows with
ramifications to the erosion of the Martian outflow channels. Icarus 42:317-329-
Laird, J. R., and M. D. Harvey. 1986. Complex-response of a chaparral drainage basin
to fire. Pp. 165-183 in: R. F. Hadley (ed.). Drainage basin sediment delivery.
International Association of Hydrological Sciences, Publication 159, Wallingford,
United Kingdom.
Leopold, L. B. 1994. A view of the river. Harvard University Press, Cambridge,
Massachusetts.
Leopold, L. B., and M. G. Wolman. 1957- River channel patterns: Braided, meandering
and straight. U.S. Geological Survey, Professional Paper 282-B, Washington, D.C.
Leopold, L. B., M. G. Wolman, and J. P Miller. 1964. Fluvial processes in geomorphology.
WH. Freeman, San Francisco, California.
Likens, G. E., and R. E. Bilby. 1982. Development, maintenance and role of organic
debris dams in New England streams. Pp 122-128 in: F. J. Swanson, et al. (eds.).
Channel CH-33
-------
Sediment budgets and routing in forested drainage basins, U.S. Department
of Agriculture Forest Service, General Technical Report PNW-141, Portland,
Oregon.
Limerinos, J. T. 1970. Determination of the Manning coefficient from measured bed
roughness in natural channels. U.S. Geological Survey, Water-Supply Paper
1898-B, Washington, D.C.
Matherne, A. M., and K. L. Prestegaard. 1988. Hydrologic characteristics as a
determinant of sediment delivery in watersheds. Pp. 89-96 in: M. P. Bordas
(ed.). Sediment budgets. International Association of Hydrological Sciences,
Publication 174.
McGuiness, J. L., L. L. Harrold, and W M. Edwards. 1971. Relation of rainfall energy
and streamflow to sediment yield from small and large watersheds. Journal of Soil
and Water Conservation 26:233-235-
Miall, A. D. 1996. The geology of fluvial deposits: Sedimentary facies, basin analysis and
petroleum geology. Springer-Verlag, Berlin.
Moglen, G. E., and R. H. McCuen. 1988. Effects of detention basins on in-stream
sediment movement. Journal of Hydrology 104:129-140.
Montgomery, D. R., and J. M. Buffmgton. 1993- Channel classification, prediction
of channel response and assessment of channel condition. Washington State
Department of Natural Resources, TFW-SH10-93-002, Olympia, Washington.
Montgomery, D. R., and J. M. Buffmgton. 1997- Channel-reach morphology in
mountain drainage basins. Geological Society of America Bulletin 109:596-611.
Myers, W L., and R. L. Shelton. 1980. Survey methods for ecosystem management. John
Wiley & Sons, New York, New York.
Naiman, R. J., D. G. Lonzarich, T. J. Beechie, and S. C. Ralph. 1992. General principles
of classification and the assessment of conservation potential in rivers. Pp.
93-123 in: P. J. Boon, P Carlow, and G. E. Petts (eds.). River conservation and
management. John Wiley and Sons, Chichester, England.
page
CH-34 Channel
-------
Nanson, G. C., and J. C. Croke. 1992. A genetic classification of floodplains.
Geomorphology 4:459-486.
Pleus, A. E., and D. Schuett-Hames. 1998. TFW Monitoring Program method manual
for the reference point survey. Prepared for the Washington State Department of
Natural Resources under the Timber, Fish, and Wildlife Agreement, TFW-AM9-
98-002, DNR#104, Olympia, Washington.
Potyandy, J. P., andT. Hardy. 1994. Use of pebble counts to evaluate fine sediment increase
in stream channels. Water Resources Bulletin 30:509-520.
Reid, L. M., andT. Dunne. 1996. Rapid evaluation of sediment budgets. Catena Verlag,
Reiskirchen, Germany.
Richards, K. 1982. Rivers: Form and process in alluvial channels. Methuen, London.
Richards, K. 1990. Fluvial geomorphology: initial motion of bed material in gravel-bed
rivers. Progress in Physical Geography 14(3):395-415-
Rosgen, D. L. 1994. A classification of natural rivers. Catena 22:169-199-
Schumm, S. A. 1977- The fluvial system. Wiley Interscience, New York, New York.
Strahler, A. N. 1952. Dynamic basis of geomorphology. Geological Society of America
Bulletin 63:923-938.
Thome, C. R. 1997- Channel types and morphological classification. Pp. 175-222 in:
A. Gurnell and G. Petts (eds.). Changing river channels. John Wiley and Sons,
Chichester, England.
Trimble, S. W 1983- A sediment budget for Coon Creek basin in the Driftless Area,
Wisconsin, 1853 to 1977- American Journal of Science 283:454-474.
U.S. Geological Survey (USGS). 1989- Water Resources Data - California, Water Year
1988, Vol. 4. U.S. Geological Survey, Water-Data Report CA-88-4.
Channel CH-35
-------
Vanoni, V. A. 1975- Sedimentation engineering. American Society of Civil Engineers,
New York, New York.
Washington Forest Practices Board (WFPB). 1997- Standard methodology for
conducting watershed analysis, version 4.0. Timber/Fish/Wildlife Agreement and
WFPB, Olympia, Washington.
Whiting, P. J., and J. B. Bradley. 1993- A process-based classification system for
headwater streams. Earth Surface Processes and Landforms 18:603-612.
Wolman, M. G. 1954. A method of sampling coarse river-bed material. Transactions of
the American Geophysical Union 35:951-956.
Woolfe, K. J., and J. R. Balzary. 1996. Fields in the spectrum of channel style.
Sedimentology 43:797-805-
CH-36 Channel
-------
Form C1. Historical channel changes
Channel
segment(s)
Historical changes
Other observations
Channel
page
CH-37
-------
Form C2. Geomorphic channel type characteristics
Channel
type
Description
Channel
segments
Potential responsiveness rating
Sediment
Runoff
Vegetation
Evidence supporting rating
page
CH-38
Channel
-------
Erosion
-------
Background and Objectives
The purpose of the Erosion module is to characterize the physical landscape of the
watershed and assess its susceptibility to erosion from natural processes and land use
practices. The primary product is a geomorphic land type map that categorizes areas based
on topographic, geologic, and soil properties and identifies the erosion potential of each
land type. Geomorphology is the study of landforms. It focuses on the processes that
create landforms, such as rainfall and runoff, and the relation of geologic material to surface
features (Dunne and Leopold 1977). Geomorphic information can be used to forecast the
effects of different land use practices on the landscape.
The Level 1 procedure relies primarily on existing information about erosion in the
watershed. Topography, soil, and geology maps are used to delineate land types based on
physical landscape characteristics. The objective of a Level 1 assessment is to generally
correlate erosion potential with various land types. Further evaluation and data collection
in a Level 2 assessment are often necessary to validate land type erosion potentials.
Level 2 methods require expertise in evaluating geology, soils, and erosion processes.
Erosion processes are evaluated in more detail, and the assessment typically involves field
surveys. A greater effort is made to quantify sources of erosion from natural processes
and land use activities.
Erosion
ER-1
-------
Erosion Module Reference Table
Critical Questions
Information
Requirements
Level 1
Methods/Tools
Level 2
Methods/Tools
E1:
What and where are the dominant ero-
sion processes in the watershed?
E2:
How do land use activities affect erosion
processes?
E3:
What geomorphic land types exist in the
watershed and where are they located?
E4:
Where and how much has soil compac-
tion reduced the productivity of soil in
the watershed?
E5:
How significant an erosion process are
landslides in the watershed?
E6:
Is sheetwash erosion a significant source
of sediment in the watershed?
E7:
Is erosion from roads or road manage-
ment practices a significant source of
sediment in the watershed?
E8:
Has natural wildfire or modern fire sup-
pression had an influence on erosion in
the watershed?
• Aerial photos
• Soil surveys
• Geology maps
• Topography maps
• Interviews (anecdotal information)
• Aerial photos
• Soil surveys
• Topography maps
• Interviews (anecdotal information)
• Aerial photos
• Soil surveys
• Geology maps
• Topography maps
• Soil characteristics
• Road density data
• Land use maps
• Landslide rates
• Landslide volumes
• Aerial photos
• Soil characteristics
• Precipitation data
• Slope length and gradients
• Vegetation cover
• Land use maps
• Interviews (anecdotal information)
• Road mileage
• Percent stream delivery
• Road characteristics
• Aerial photos
• Aerial photos
• Vegetation maps
• Review of existing map and
survey data
• Erosion severity classification
• Review of existing map and
survey data
• Review of existing map and
survey data
• Land type classification
• Estimate the amount and loca-
tion of compacted areas
• Review of existing soil map and
survey data
• General landslide inventory
• Review of existing soil map and
survey data
• Inventory of general road char-
acteristics
• Determine frequency of
stream/water crossings by roads
• Detailed field review of erosion
• Revised Universal Soil Loss
Equation (RUSLE)
• Water Erosion Prediction Proce-
dure (WEPP)
• Detailed field review of erosion
• RUSLE
• WEPP
• Review of aerial photos
• Field review of geomorphic land
types
• Current/historical aerial photo
analysis
• Field surveys to evaluate current
soil compaction hazard
• Detailed landslide inventory
• Field Surveys
• Field surveys to estimate annual
erosion rates
• RUSLE
• WEPP
• Washington State Forest Road
Erosion Model
• USFS R1-R4 Forest Road Ero-
sion Model
• RUSLE
• Reconstruct fire history
• Evaluate current and historical
vegetation maps
• Field surveys to evaluate erosion
rates or fire frequency and
intensity
page
ER-2
Erosion
-------
Erosion Module Reference Table (continued)
Critical Questions
Information
Requirements
Level 1
Methods/Tools
Level 2
Methods/Tools
E9:
Is gully erosion an important source of
sediment in the watershed, and have
erosion rates changed over time?
Aerial photos
Anecdotal information
Soil maps and survey data
Review of existing soil map and
survey data
Current and historical aerial
photo analysis of gullies
Field surveys to estimate current
annual erosion rate
E10:
How significant a sediment source is
streambank erosion in the watershed,
and how have erosion rates changed
over time?
Aerial photos
Existing stream survey data
Anecdotal information
• Current and historical aerial
photo analysis of bank erosion
• Field surveys to evaluate current
bank erosion rates
E11:
Do other significant erosion processes
occur in the watershed that have not
been accounted for by other evaluations?
Topography maps
Soil maps
Wind erosion model
Field surveys to evaluate extent
of dry ravel and soil creep
E12:
What are the primary sources of sedi-
ment delivery to streams, lakes, wet-
lands, or other waterbodies in the water-
shed?
Soil maps and survey data
Topography maps
Aerial photos
Sediment budget
RUSLE
Soil creep estimation
Erosion
ER-3
-------
Level 1 Assessment
Step Chart
Data Requirements
• Topographic maps
• Geology maps
• Soil maps
• Geomorphology or land type maps
(if available)
• Slope class map (as necessary)
• Aerial photos (as necessary)
Products
• Form El. Summary of erosion
observations
• Form E2. Summary of land type
characteristics
• Map El. Land types
• Erosion report
Procedure
Collect and evaluate
available information on erosion
Create a draft land type map based
on geology, soils, and topography
Assign relative erosion potential ratings
and create a refined land type map
Produce Erosion report
The focus of the Level 1 assessment is to evaluate the erosion potential of land types that
occur in the watershed. Land types are areas with generally uniform characteristics and
physical features (e.g., topography, soils) produced by natural processes. Even if erosion
is not an issue in the watershed, determining land types may be a helpful exercise to
understand other ecological characteristics such as vegetation communities or water quality.
Consult with other module analysts early in the assessment to determine the level of detail
and the scale of land type mapping that would be most helpful.
page
ER-4
Erosion
-------
Step 1. Collect and evaluate available information on erosion
Collect anecdotal information
Consult people who are knowledgeable about soils, geology, or erosion processes and are
familiar with the watershed to help identify the type and location of erosion problems.
State natural resource departments or local agricultural offices often have experts familiar
with local erosion problems. The NRCS, USFS, BLM, and USGS offices may also have
resources available to evaluate erosion within the watershed. Another source of experts is
a university or local college, where professors might have a great deal of knowledge about
local erosion issues. Finally, local land managers may be knowledgeable about erosion in
the watershed over time and the type of land use activities that have caused problems.
Figure 1 summarizes the potential effects of land use activities on erosion processes and
community resources.
Collect topography, geology, and soil maps
Topography, geology, and soil maps are important resources for evaluating the erosion
potential in the watershed. USGS 7-5-minute topography maps are typically the most
useful scale for evaluating erosion at a watershed scale. Topography maps can be used to
identify steep slopes as well as slope shapes (e.g., concave, undulating, planar) with higher
erosion potential. They can usually be obtained locally at map or outdoor recreation stores,
or they can be ordered directly from the USGS.
Geology and soil maps are often useful tools for evaluating baseline watershed conditions.
Coordinate with the Channel, Vegetation, and Water Quality analysts to determine the
type and scale of geology or soil information that would be most useful for evaluating
differences in watershed conditions. USGS and state geology maps can provide helpful
information on both bedrock and surficial geology. Some geologic formations may be
naturally prone to erosion or be sensitive to land disturbance. These maps can be found
at most university libraries, state geology departments, and USGS offices. Soil maps can
provide important information about soil properties and may correlate well with specific
land types. These maps can be found at most university libraries, state soil or agricultural
offices, and NRCS offices. Both geology and soil maps are available as GIS overlays in
many states.
Evaluate erosion information
Using information on topography, geology, and soils and anecdotal information on erosion
problems, determine whether landslides, streambank slumping, and surface erosion are
Channel
Vegetation
Water Quality
Erosion
ER-5
-------
Figure 1. Potential linkages between land use practices, erosion processes,
and community resources
Potential Land Uses
Agriculture Urban
Forestry Grazing
Mining
Potential Land Impacts
Vegetation removal
• Heavy machinery, grazing
• Road construction ^^^"
Change in volume or timing of runoff
Industrial and agricultural runoff
Increased soil exposure
Decreased soil cohesion
Increased soil compaction
Increased slope of land
Increased sediment delivery
Chemical and nutrient
deposit
Erosion Processes
Soil creep
Mass wasting
- shallow landslides
- deep-seated landslides
- rockfalls
- snow avalanches
Surface erosion
- gully erosion
- sheetwash erosion (rainsplash and rill erosion)
- ravel (dry and freeze/thaw)
Community Resources
Erosion Impacts
• Loss of soil
Transport of soil
Deposit of soil i
Affected Resources
Land productivity, structures
Water supply, aquatic life
Structures, aquatic habitat,
reservoir capacity, flood hazard
page
ER-6
Erosion
-------
potentially active in the watershed and where they are potentially active. Aerial photos
may be helpful in identifying larger areas with active erosion. If road erosion is a potential
concern in the watershed, it may be helpful to gather information on road network
characteristics, such as maintenance level, road density, and the frequency of stream/water
crossings. Consult with the Aquatic Life and Channel analysts to determine the need for
evaluating streambank erosion and the assessment detail. Form El (Figure 2) or a map
that depicts similar information may be useful for summarizing observations and noting
particular geologic formations or soil types that may be prone to erosion naturally or from
management practices in the watershed.
Aquatic Life
Channel
Figure 2. Sample Form E1. Summary of erosion observations
Number
1
2
3
Erosion Feature
Raw banks
Sheetwash ero-
sion
Gully erosion
Location
Lower Silk Creek
Road cuts on 60% slopes
in the sandstone geology
of Cispus River
Throughout the watershed
on slopes > 30%
Observations
Aerial photos and observations by tribal monitoring crew
indicate unstable banks.
Field investigation and county engineering reports indi-
cate erosion problems on road cuts.
Aerial photos, field observation, and anecdotal informa-
tion show gully erosion in the headwaters of most
streams and below road drainage pipes.
Step 2. Create a draft land type map based on geology, soils, and topography
Land types typically represent a feature with generally uniform shape and soil
characteristics (Box 1). Land types should encompass the area created by a single
geomorphic process (e.g., fluvial, glacial, colluvial, marine) with a set of characteristic
features (Figure 3). For
example, fluvial processes Box 1' Pe"°kscot Nation evaluation of land types
can create land types such as
floodplain terraces, alluvial
fans, and playas. Box 2
provides a list of commonly
described geomorphic land
types from across the
United States. These land
types are provided only as
A geomorphic evaluation of the Penobscot River basin by the Penobscot Nation in
Maine highlighted eskers as a land type with potentially important influence on Atlan-
tic salmon habitat. Eskers are glacial outwash deposits from streams that flowed
beneath the continental ice sheet and form narrow bands that generally parallel the
Penobscot River. Where eskers cross the Penobscot River or its tributaries, gravel
appears to be more prevalent and provides potentially important spawning habitat for
salmon. Eskers may also be an important source of groundwater to streams to main-
tain cool water temperatures.
Erosion
ER-7
-------
Figure 3. Landforms in the Thompson River basin, Montana
Alpine Glaciated Lands
l~l Cirque and rock ridge
I I Glacial basin
n Glacial trough
n Moraine
Fluvial Lands
l~l Mountain ridge
n Mountain slope
n Breakland
Continental Glaciated Erosional Lands
CH Glacial ridge and slope
Continental Glaciated Depositional Lands
n High terrace
n Floodplain and alluvium
Miscellaneous
CH Water
Note: Hydrology from 1:24,000 scale USFS Cartographic Feature Files
Landtype Associations compiled from Lolo and Kootenai National
Forest landtype mapping and from NRCS soil mapping.
page
ER-8
Erosion
-------
examples, and the Erosion analyst will
need to create land type descriptions
best suited to the watershed. Two
publications that may be helpful are
Ritter et al. (1995), which provides a
good summary of geomorphic processes
that shape landscapes, and Raskins et
al. (1998), which describes a geomorphic
classification system.
Box 2. Examples of geomorphic land types from
across the United States
Alluvial fan
Arroyos
Alpine glaciated basin
Avalanche-prone hillslopes
Badlands
Backshore terrace
Basin floor depressions
Canyonlands
Chenier plain
Cliffs
Coastal marshlands
Dissected planar slopes
Esker
Floodplain terrace
Glacial moraine
Glacial outwash terrace
Karst limestone topography
Kettle outwash plains
Landslide deposit
Loess deposit
Marine terrace
Mesas
Piedmont
Plateau
PI ay a
Prairie potholes
Rockland
Slough bottomlands
Talus
Tidal mudflats
Till plain
Valley flat
Valley headwall
Wet meadows
A watershed can have a large range of
land types depending on the scale of
assessment. Since no strict criteria exist
for defining land types, the scale of
assessment should be determined by the
objectives of the Erosion assessment.
In general, a finer scale (e.g., swales
> 40% slope) will be most useful
for addressing specific land management
activities, while a broader scale (e.g., glaciated uplands) may be more helpful for
quantifying general erosion rates. Consult with other module analysts to help determine
the best assessment scale. In particular, coordinate with the Channel analyst, who will be
identifying channel types based on geomorphic characteristics similar to land types.
Geologic maps are often useful for identifying land types at a broad scale. Soil surveys
typically provide information at finer scales and can be particularly helpful in identifying
land types near streams and rivers. Figure 4 shows examples of soil association patterns.
The correlation of soil types and geomorphology is commonly described in soil surveys.
Soil types can be used individually or in aggregate to describe a land type. Geology and soil
information may also be available as GIS overlays complete with erosion potential ratings.
Erosion potential or erosion hazard ratings should be examined using the available data to
evaluate their accuracy and applicability to the watershed.
Land types can be further refined using modifiers such as slope gradient, slope position,
slope shape, and dissection frequency or pattern (Box 3). These land type modifiers can
help focus the analysis on specific areas where erosion is most problematic. In some
Channel
Erosion
ER-9
-------
Figure 4a. Correlation between soil types and geomorphology in Maine
Note that the Colton soils
correlate directly with the
eskers land type.
Figure 4b. Correlation between soil types and geomorphology
in Washington State
page
ER-10
Erosion
-------
Box 3. Slope class maps
Since slope gradient is often a primary factor influencing erosion potential, it may be useful
to divide the watershed into similar slope classes. The increment used for slope classes will
depend on the total relief of the watershed. Relatively low-relief watersheds typically will
have slope class increments of 1-5 percent, while high relief watersheds may have incre-
ments of 5-20 percent. GIS programs can be used to efficiently create this type of map.
cases, it may also be useful to consider other ecological factors such as vegetation,
climate, or aspect to help differentiate land types. Where possible, land types should be
differentiated based on natural processes and not changes due to land use.
Step 3. Assign relative erosion potential ratings and create a refined
land type map
Correlate the land types with information on erosion in the watershed. If a GIS
system is available, it may be useful to overlay geology or soils maps with land use
activities to highlight potential erosion concerns. It may be necessary to modify land
type boundaries or develop new land types to best distinguish specific areas susceptible
to erosion problems. Create a final land type map (Map El) to use during the
Synthesis process. Assign relative erosion potential ratings to each land type based on
its susceptibility to mass wasting and surface erosion. It is important to remember
that the erosion potential ratings in all but the most obvious cases will be hypotheses
requiring additional information and further evaluation. Summarize information for
each land type in Form E2.
Step 4. Produce Erosion report
The Erosion report should summarize geologic and soil characteristics, erosion processes
in the watershed, and land management effects on erosion. The report will typically
include the following components:
1. Site Description
- Geology
- Soil types
- Topography
- Erosion processes
Erosion ER-11
-------
2. Assessment methodology
- Materials (e.g., aerial photo series and source)
- Survey methods
- Assumptions
3- Results of the assessment
- Form El. Summary of Erosion observations
- Form E2. Summary of land type characteristics
- Map El. Land types
4. Conclusions
- Erosion trends
- Land management effects
- Further data and assessment needs
- Confidence in assessment
5. References
page
ER-12 Erosion
-------
Level 2 Assessment
The organization of this section generally corresponds to the critical questions listed in
the Erosion Module Reference Table. Most of the critical questions relate to a specific
topic that can be evaluated using a number of methods or tools. For each topic, a general
description of methods, guidance on the appropriate use of methods, and the expertise and
time-frame required to complete the assessment are provided. Suggested references are also
provided for more detail on available data, methods, and tools.
So/7 Compaction
Soil compaction is typically caused by either the use of heavy machinery, such as for
building construction and ground-based logging, or trampling due to animal grazing or by
people, such as at heavily used recreation areas. Soil compaction may be a concern because
of reduced water infiltration or reduced soil productivity for vegetation growth.
The sensitivity of soil to compaction is largely a function of soil texture. Soil texture
is the relative proportion of sand, silt, and clay particles in a mass of soil. Soil with
a high percentage of clay may be easily compressed. On the other hand, soil with a
high percentage of sand cannot be easily compressed; thus it maintains its structure under
heavy loads.
The primary method for evaluating large-scale soil compaction from urbanization, roads,
and grazing is examining aerial photos. Land use maps may also provide useful
information, although it may not be as accurate as information from a photo survey. To
evaluate small-scale soil compaction and the degree of compaction, field surveys will be
necessary. Soil compaction testers or penetrometers can be used to gather data on the
compressive strength of the soil. Soil compaction from grazing or camping may only
be a problem in isolated areas, such as near streams or lakes. It may also be possible
to correlate field observations of compaction with specific soil types to help predict the
potential for future compaction problems. Measuring and evaluating soil compaction can
be easily done without extensive training, although a soil scientist may be needed for more
intensive evaluations.
Erosion ER-13
-------
Landslides
Landslide evaluation on a watershed scale typically involves aerial photo analysis and
creation of a landslide inventory. Typically, l:25,000-scale or finer aerial photos are needed
to accurately identify landslides. Orthophotos, if available, can be an important aid to
transfer data from aerial photos to topographic maps. The landslide inventory should
cover the longest period of record possible by using the oldest aerial photos through the
most current photos. A long aerial photo record is important for evaluating the rate of
rapid failures, such as debris flows and rockslides because of their episodic occurrence from
infrequent large storms, and the movement rate of slumps and earthflows that may progress
intermittently over months to centuries.
A comprehensive landslide inventory can be used to collect data that relate important
variables to the risk of occurrence. A landslide inventory can include data on location
(e.g., township, range, and section number), year of occurrence, type of landslide, hillslope
gradient, parent material, slope form, soil type, land use trigger, or sediment delivery to
a stream (Figure 5).
Figure 5. Sample landslide inventory form
Site*
1
2
3
Location
21N, 15ESec. 2
20N, 13ESec. 31
21N, 12ESec. 11
Year
1968
1993
1951
Type
Shallow rapid
Deep-seated
Rockfall
Gradient (%)
70-80
30
60
Trigger
Road
Natural
Natural
Stream Delivery
Yes
No
No
Some training and experience are necessary to accurately identify landslides on aerial
photos, particularly for older, inactive, or deep-seated landslides. Some field measurements
may also be necessary to estimate the minimum identifiable size of landslide observable on
aerial photos, landslide volumes, the frequency of smaller slides, and the frequency of slides
hidden under forest canopy (Reid and Dunne 1996). Uncertainties in the aerial photo
interpretation may be related to the following:
• Physical conditions that contributed to the landslide.
• Land use trigger mechanisms.
• Delivery of sediment to public resources.
• Extrapolation from areas of known hazard to areas of unknown hazard.
page
ER-14
Erosion
-------
Further information on creating landslide inventories can be found in Sidle et al.
(1985), the federal guide for watershed analysis (RIEC and IAC 1995), the Washington
State watershed analysis manual (WFPB 1997), and the Oregon watershed assessment
manual (Watershed Professionals Network 1999). NCASI (1985) contains data from
landslide inventories in the Pacific Northwest.
Sheetwash Erosion
Sheetwash erosion is movement of soil particles caused by rainsplash and rill erosion.
Sheetwash erosion occurs naturally in areas with generally sparse vegetation or after
wildfire but can also be prevalent in agricultural croplands and rangelands.
Table 1 contains the results of soil loss measurements from hillside plots around North
America under different land use conditions. These data can be used to derive a crude
but quick estimate of erosion in a watershed. It is important to note that these soil
loss estimates do not address sediment delivery to streams. Sediment delivery distances
need to be estimated along with average soil loss to evaluate sheetwash erosion impacts
to streams.
Revised Universal Soil Loss Equation
The most commonly used model to predict sheetwash erosion under various land
uses is the Revised Universal Soil Loss Equation (RUSLE) (Renard et al. 1997). The
publication by Renard et al. (1997) should be consulted for more detailed information
and application of the RUSLE. Use of this model typically requires some expertise
and familiarity with conducting erosion studies. A GIS system is also very helpful for
simplifying many of the steps.
The RUSLE is best used for agricultural lands in the central and eastern United States,
although refinements in values and additional data from the western United States allow
its use in most agricultural areas (Renard et al. 1997). The latest version of the RUSLE
(Renard et al. 1997) replaces previous versions published by the USDA.
Erosion ER-15
-------
Table 1. Measurements of soil loss from hillside plots
Land Use
Location
Soil Loss (tons/acre/yr)
Source
Forest
Primeval
Burned annually
Primeval
Burned semiannually
Woodland, protected
Woodland, burned annually
Woodland, protected
Woodland, protected
Agriculture, Cultivated Grasslands
Bluegrass
Alfalfa
Clover and grass
Bermuda grass
Fescue grass
Hayland
Hayland
Tropical perennial grasses
Tropical kudzu
Agriculture, Croplands
Bare fallow
Bare fallow
Corn
Corn
Rangeland
Dry woodland and rangeland
Dry woodland and rangeland, after fire
Dry woodland and rangeland
Sparse grassland
Urban
Road cuts
Building sites
Building sites
Mining
Land devegetated by smelter fumes
Spoil bank
Rural Roads
Forest roads
Forest roads
Oklahoma
Oklahoma
North Carolina
North Carolina
Texas
Texas
Ohio
North Carolina
Midwestern U.S.
Midwestern U.S.
Virginia
Southwest U.S.
Georgia
Washington
North Carolina
Puerto Rico
Puerto Rico
Georgia
Midwestern U.S.
Midwestern U.S.
Midwestern U.S.
Southern California
Southern California
New Mexico
Alberta
Georgia
Maryland
Maryland
Ontario
Ohio
Idaho
Idaho
0.01
0.11
0.002
3.08
0.05
0.36
0.01
0.08
0.02-0.34
0.03-0.15
0.01-0.07
0.00-0.10
0.20
0.01-0.08
0.31
1.2
0.18
100
69
17.86
73.2
2.7
24.7
21.2
7.7
79-237
125-219
189
26.1
87
29.7
7.9
Smith and Stamey (1965)
Smith and Stamey (1965)
Smith and Stamey (1965)
Smith and Stamey (1965)
Smith and Stamey (1965)
Smith and Stamey (1965)
Smith and Stamey (1965)
Smith and Stamey (1965)
Smith and Stamey (1965)
Smith and Stamey (1965)
Smith and Stamey (1965)
Smith and Stamey (1965)
Smith and Stamey (1965)
Smith and Stamey (1965)
Smith and Stamey (1965)
Barnett(1965)
Bennet (1939)
Jamison et al. (1968)
Bennet (1939)
Krammes (1960)
Krammes(1960)
Leopold etal. (1966)
Campbell (1970)
Disekerand Richardson (1961)
Wolman and Schick (1967)
Guy (1965)
Pearce (1973)
Geotimes(1971, Dec)
Megahan and Kidd (1972)
Copeland(1965)
Adapted from Dunne and Leopold (1977)
ER-16
Erosion
-------
The RUSLE is as follows:
A = R*K*L*S*C*P
Where: A = Soil loss (tons/acre)
R = Rainfall erosivity index
K = Soil erodibility factor
L = Hillslope-length factor
S = Hillslope-slope factor
C = Cropping management factor
P = Erosion control practice factor
The rainfall erosivity index (R) corresponds to the average annual energy and intensity of
rainstorms and has been mapped across the United States. The soil erodibility factor (K)
is the average soil loss at a specific rainfall erosivity when the soil is exposed as cultivated
bare fallow. The soil erodibility factor has also been calculated for different soils across
the country and is listed in most NRCS (formerly the SCS) soil surveys. The effect of
topography is accounted for by the hillslope-length (L) and hillslope-slope (S) factors.
Hillslope-slope factors can be estimated in the field using inclinometers or levels or in
the office using topographic maps (maps with 2-foot contour intervals are recommended).
Topographic factors for uniform hillslopes under various land use conditions, such as
cropland, rangeland, or construction sites are listed in Renard et al. (1997). The cropping
management factor (C) and the erosion control practice factor (P) account for vegetative
cover and soil tillage practices, respectively. Tables with a range of factors, as well as more
detailed assessments for site-specific determinations of both C and P, can be found in
Renard et al. (1997).
The RUSLE is best used on smaller drainage basins by dividing the basin into areas of
uniform soil type, topography, and agronomic conditions. The soil loss can then be
computed for each combination. This exercise is greatly simplified if GIS can be used.
The RUSLE predicts the amount of soil moved from its original position and does not
necessarily predict the amount of sediment transported out of an area or watershed.
The delivery of sediment into streams or other sediment-transport conduits (e.g., gullies,
ditches, canals) must be considered as a separate step. Ebisemiju (1990) found that
sediment delivery was correlated with hillslope gradient and infiltration rates on bare
soils but was best predicted by slope length and soil erodibility on vegetated surfaces. If
Erosion ER-17
-------
redeposited sediment is observed during field work, its relation to factors such as gradient,
surface roughness, vegetation cover, storm runoff, and distance from the sediment source
should be noted to identify the conditions under which delivery may be significant (Reid
and Dunne 1996).
Water Erosion Prediction Procedure
The Water Erosion Prediction Procedure (WEPP) is now being developed to take the place
of the RUSLE (Nearing et al. 1989)- WEPP is designed to be more process-based and have
wider applicability to cropland, rangeland, and forestland. Independent versions are being
developed for hillslopes, small watersheds, and GIS-based grid cells. Both the hillslope and
small watershed versions are expected to be PC-based expert programs (Reid and Dunne
1996). Contact the NRCS for further information about the availability of WEPP.
Road Erosion
Road surface erosion is generally evaluated separately from sheetwash erosion because of its
wide distribution and importance (Reid and Dunne 1996). A number of factors can affect
the production of sediment from roads, including surfacing material, traffic levels, rainfall,
and drainage design. Road erosion is typically of greatest concern at stream crossings,
although roads parallel to streams can also cause sedimentation problems.
Watershed-scale road erosion is typically evaluated by developing an average annual rate
of erosion multiplied by the area of road delivering directly to waterbodies. Erosion rates
from forest roads have been calculated for a number of regions of the country. Regional
examples of forest road erosion data and empirically-based road erosion models include
the following:
• Appalachian forest road data (Kochenderfer and Helvey 1984, 1987; Swift 1984).
• Pacific Northwest road data (Reid and Dunne 1984; Bilby et al. 1989) and watershed
analysis road erosion model (WTPB 1997).
• Interior West road data (Megahan and Kidd 1972; Burroughs and King 1989) and
R1-R4 model (Reinig et al. 1991; Ketcheson et al. 1999).
The previously discussed RUSLE and WEPP models can also be adapted to estimate road
surface erosion.
page
ER-18 Erosion
-------
Gully Erosion
Gully erosion can often occur in response to roads, grazing, or agricultural impacts in
fine-grained, cohesive soils. Evaluating gully erosion typically involves aerial photo and
field surveys to estimate the distribution and density of gullies and to determine an average
annual rate of incision.
Gully widths can often be translated into volumes by using field measurements to relate
width and cross-sectional area. The SCS (1977) found that widths of active gullies are
typically about 3 times their depth in cohesive soils but only 1.75 times their depth in
non-cohesive soils. This report also provides equations for predicting future rates of gully
head retreat based on drainage area and rainfall intensities. With any equation or predictive
model, it is important to evaluate its assumptions and make sure they are applicable to the
watershed being investigated. Field evidence can be used to verify retreat rates by noting
when particular structures, trees, fences, and roads are affected by the gully. Cooke and
Reeves (1976) used this type of field evidence to track arroyo networks in the southwestern
United States.
Streambank Erosion
The rate of Streambank erosion can depend on a number of factors, including flood
discharge, previous precipitation, bank material, and vegetation. Bank erosion along large
streams can typically be observed on sequential aerial photos. The average rate of lateral
retreat together with field measurements of bank height can be used to estimate sediment
production rates. Examples of studies that have examined bank erosion in different parts of
the United States include the following:
• California (Lehre 1982).
• Ontario, Canada (Dickinson et al. 1989).
• Utah (La Marche 1966).
The Channel module may also gather information on Streambank erosion, so it is Channel
important to coordinate activities.
Erosion ER-19
-------
Other Erosion Processes-Soil Creep, Dry Ravel, and Wind Erosion
Soil creep is the slow downhill movement of the soil mantle that results from disturbance of
the soil by freeze/thaw processes, wetting or drying, or plastic deformation under the soil's
own weight (Dunne and Leopold 1977)- Other soil displacing processes such as tree throw
and biological activity are typically included in estimates of soil creep.
Measured soil creep rates typically range from 0.001 to 0.002 m per year in the United
States. Saunders and Young (1983) contains a compilation of measured rates of soil creep
and other surface erosion processes from around the world. Soil creep rates may be higher
in areas of clay-rich soil and in areas with active earthflow movement. Local soil creep rate
data may also be available from a monitoring program.
Soil creep rates are often used to estimate bank erosion of colluvial material. Colluvium is
the soil and rock debris on a hillslope that has been transported from its original location.
This type of bank erosion generally occurs in small streams that are tightly confined.
Soil creep supplies sediment to the bank, and the rate of sediment supply to the bank is
assumed to be equal to the rate of bank erosion. Further detail on assessment of soil creep
is provided in the next section.
Dry ravel is most prevalent on steep, sparsely vegetated slopes. Ravel is capable of moving
larger particles than sheetwash erosion, and the sediment tends to accumulate in small
talus cones and sediment fans (Reid and Dunne 1996). Ravel rates are typically highest
during freeze/thaw and wet/dry periods, after fires that have consumed fallen logs and other
organic debris on hillslopes, or on near-vertical streambanks and roadcuts. Exposure of tree
roots and accumulation of sediments can be evaluated in field surveys to estimate rates of
dry ravel (Megahan et al. 1983; Reid and Dunne 1984; Reid 1989).
Since wind erosion does not supply sediment preferentially to streams, sediment
production from this source is often ignored. If necessary, input rates can be estimated by
assuming channel inputs are proportional to the fraction of the land surface occupied by
channels and ponds (Reid and Dunne 1996).
Evaluation of Watershed-Scale Sources of Erosion
A sediment budget is a tool used to determine the relative sources of sediment from various
erosion processes, natural and management-related. A complete sediment budget considers
the sources and storage of sediment and the export of sediment from the watershed. While
fige
ER-20 Erosion
-------
the method is generally quantitative, the estimates are considered order-of-magnitude
values. Sediment budgets that focus on the sources and relative contribution of sediment
to channels can be useful for comparing natural sources of sediment (soil creep, fires,
natural mass wasting, etc.) with management-related sources of sediment (e.g., erosion
from agriculture, forest roads, urban construction sites, grazing). The relative differences
can be used to better judge the impacts of changes in land use and to help focus efforts
for improved management.
These methods typically require expertise in evaluating watershed-scale erosion and
experience developing sediment budgets. Reid and Dunne (1996) and Swanson (1983)
provide more detailed descriptions and examples of sediment budgets. Constructing a
sediment budget will require coordination with the Channel analyst to address sediment Channel ^
transport and storage issues.
Two approaches to estimating natural sediment production are discussed in this section: the
soil creep model and the empirical sediment yield approach. The soil creep model is best
used in watersheds with high topographic relief and a relatively small amount of alluvial
bank cutting and when sediment yield data from the watershed or other nearby comparable
watersheds are sparse. The empirical sediment yield approach relies on available data
(typically from the USGS), generally collected on larger rivers, and can be used for most
watershed types. If data on sediment yield are available and the soil creep model seems
appropriate for the watershed, both methods should be used to get an idea of the range
of error in the estimates. Both approaches are best at predicting the amount of finer
sediment (sand-sized and smaller) exported from a watershed and may not capture bedload
movement of larger particle sizes.
Soil creep model
The soil creep model provides an estimate of sediment yield from colluvial hillslope
sources. Watershed sediment yield can be calculated using the following equation:
SY = C*2*L*D*SD
Where: SY = Sediment yield (tonnes/yr)
C = Creep rate (m/yr)
L = Length of stream (m)
D = Average soil depth (m)
SD = Average bulk density of soil (tonnes/m3)
Erosion ER-21
-------
The creep rate is multiplied by the total stream length times 2 to account for creep on both
sides of the channel. Stream lengths can be easily calculated using GIS, but the level of
accuracy may need to be verified. Small streams may not be mapped and may constitute
a large proportion of the stream network. Average soil depths can be estimated using soil
survey information for the watershed. If soil depth varies significantly across the watershed,
it may be necessary to break up the watershed into areas of uniform soil depth and then
calculate erosion rates for each area. The bulk density of soil typically ranges from 1.2 to
1.7 tonnes/m3 (SCS 1986). In the absence of watershed or regional data, an average bulk
density of 1.5 tonnes/m3 is typically used.
Empirical sediment yield approach
Where available, sediment yield data can provide accurate estimates of sediment production
from watersheds. The USGS typically collects these data for watersheds around the
country, but other sources may be available as well (Larsen and Sidle 1980; Dendy and
„. . Champion 1978). The sediment yield data should extend at least a few years and should
especially cover times of higher streamflow, when the majority of sediment is transported.
If these data are to be used as estimates of natural sediment production, the history of
land use during the period of record should also be investigated. Where extensive land
use practices have potentially increased erosion during the period of sediment yield data
collection, the background rate can be back-calculated using information on management-
related sources of sediment.
page
ER-22 Erosion
-------
References
Bilby, R. E ., K. Sullivan, and S. H. Duncan. 1989- The generation and fate of
road surface sediment in forested watersheds in southwestern Washington. Forest
Science 35(2):453-468.
Burroughs, E. R., Jr., and J. G. King. 1989- Reduction of soil erosion on forest roads.
U.S. Department of Agriculture Forest Service, Intermountain Research Station,
General Technical Report INT-264, Ogden, Utah.
Cooke, R. U., and R. W. Reeves. 1976. Arroyos and environmental change in the
American Southwest. Clarendon Press, Oxford.
Dendy, F. E., and W. A. Champion. 1978. Sediment deposition in U.S. reservoirs:
Summary of data reported through 1975- U.S. Departent of Agriculture,
Miscellaneous Publication 1362, Washington, D.C.
Dickinson, W. T, R. P. Rudra, and G. J. Wall. 1989- Nomographs and software for field
and bank erosion. Journal of Soil and Water Conservation 44(6):596-600.
Dunne, T, and L. B. Leopold. 1977- Water in environmental planning. WH. Freeman
and Company, New York, New York.
Ebisemiju, F. S. 1990. Sediment delivery ratio prediction equations for short catchment
slopes in a humid tropical environment. Journal of Hydrology 114(1-2):191-208.
Raskins, D. M., C. S. Correll, R. A. Foster, J. M. Chatoian, J. M. Fincher, S. Strenger, J.
E. Keys, J. R. Maxwell, and T. King. 1998. A geomorphic classification system.
U.S. Department of Agriculture Forest Service, Geomorphology Working Group,
Washington.
Ketcheson, G. L., W F. Megahan, and J. G. King. 1999- "R1-R4" and "BOISED"
sediment prediction model tests using forest roads in granitics. Journal of the
American Water Resources Association 35(1): 83-98.
Erosion ER-23
-------
Kochenderfer, J. N., and J. D. Helvey. 1984. Soil losses from a "minimum-standard"
truck road constructed in the Appalachians. Pp. 215-225 in: P. A. Peters and J.
Luchok (eds.): Proceedings from Mountain Logging Symposium, June 5-7, 1984,
West Virginia University, Morgantown, West Virginia.
Kochenderfer, J. N., and J. D. Helvey. 1987- Using gravel to reduce soil losses
from minimum-standard forest roads. Journal of Soil and Water Conservation
42:46-50.
La Marche, V C. 1966. An 800-year history of stream erosion as indicated by botanical
evidence. U.S. Geological Survey, Professional Paper 550-D.
Larson, K. R., and R. C. Sidle. 1980. Erosion and sedimentation data catalog of
the Pacific Northwest. U.S. Department of Agriculture Forest Service, Pacific
Northwest Region, R6-WM-050-1981, Portland, Oregon.
Lehre, A. K. Sediment budget of a small coast range drainage basin in north-central
California. U.S. Department of Agriculture Forest Service, Pacific Northwest
Forest and Range Experiment Station, Portland, Oregon.
Megahan, W F, and W J. Kidd. 1972. Effect of logging roads on sediment production
rates in the Idaho Batholith. U.S. Department of Agriculture Forest Service,
Intermountain Forest and Range Experiment Station, Research Paper INT-123,
Ogden, Utah.
Megahan, W. F, K. A. Seyedbagheri, and P. C. Dodson. 1983- Long-term erosion
on granitic roadcuts based on exposed tree roots. Earth Surface Processes and
Landforms 8(l):19-28.
National Council of the Paper Industry for Air and Stream Improvement (NCASI). 1985-
Catalog of landslide inventories for the Northwest. NCASI, Technical Bulletin
456.
Nearing, M. A., G. R. Foster, L. J. Lane, and S. C. Finkner. 1989- A process-based
soil erosion model for USDA Water Erosion Prediction Project Technology.
Transactions of the American Society of Agricultural Engineers 32(5):1587-1593-
page
ER-24 Erosion
-------
Regional Interagency Executive Committee (RIEC) and Intergovernmental Advisory
Committee (IAC). 1995- Ecosystem analysis at the watershed scale: Federal guide
for watershed analysis, version 2.2. Regional Ecosystems Office, Portland, Oregon.
Reid, L. M. 1989- Channel incision by surface runoff in grassland catchments. PhD.
dissertation, University of Washington, Seattle, Washington.
Reid, L. M., and T. Dunne. 1984. Sediment production from forest road surfaces. Water
Resources Research 20(11):1753-1761.
Reid, L. M., andT. Dunne. 1996. Rapid evaluation of sediment budgets. Catena Verlag,
Reiskirchen, Germany.
Reinig, L., R. L. Beveridge, J. P. Potyondy, and E M. Hernandez. 1991. BOISED
user's guide and program documentation. U.S. Department of Agriculture Forest
Service, Boise National Forest, Boise, Idaho.
Renard, K. G. 1997- Predicting soil erosion by water: A guide to conservation planning
with the revised universal soil loss equation (RUSLE). U. S. Department of
Agriculture, Agriculture Handbook No. 703, Washington, D.C.
Ritter, D. F, R. C. Kochel, and J. R. Miller. 1995- Process geomorphology, third edition.
William C. Brown Publishers, Dubuque, Iowa.
Saunders, L, and A. Young. 1983- Rates of surface processes on slopes, slope retreat and
denudation. Earth Surface Processes and Landforms 8:473-501.
Sidle, R. C., A. J. Pearce, and C. L. O'Loughlin. 1985- Hillslope stability and land use.
Water Resources Monograph 11. American Geophysical Union, Washington D.C.
Swanson, F. J. 1983- Sediment budgets and routing in forested drainage basins. U.S.
Department of Agriculture Forest Service, Gen. Tech. Rep. PNW-141, Portland,
Oregon.
Swift, Jr., L. W 1984. Gravel and grass surfacing reduces soil loss from mountain roads.
Forest Science 30(3): 657-670.
Erosion ER-25
-------
U.S. Department of Agriculture Soil Conservation Service (SCS). 1977- Procedure for
determining rates of land damage, land depreciation and volume of sediment
produced by gully erosion. Pp. 125-141 in: S. H. Kunkle and J. L. Thames (eds.).
Guidelines for Watershed Management. FAO Conservation Guide 1. UN Food
and Agricultural Organization, Rome.
U.S. Department of Agriculture Soil Conservation Service (SCS). 1986. Methods of soil
analysis, Part 1, Physical and mineralogical methods, second edition. American
Society of Agronomy, Soil Science Society of America, Madison, Wisconsin.
Washington Forest Practices Board (WFPB). 1997- Standard methodology for conducting
watershed analysis, version 4.0. Timber/Fish/Wildlife Agreement and WFPB,
Olympia, Washington.
Watershed Professionals Network. 1999- Oregon watershed assessment of aquatic resources
manual. Draft report prepared for the Governor's Watershed Enhancement Board,
Salem, Oregon.
page
ER-26 Erosion
-------
Form E1. Summary of erosion observations
Number Erosion Feature
Location
Observations
Erosion
ER-27
-------
Form E2. Summary of land type characteristics
Land Type
Land Type
Description
Total Area
Percent of
Watershed Area
Mass Wasting
Rating
Surface Erosion
Rating
Observations
page
ER-28
Erosion
-------
vegetation
-------
Background and Objectives
Box LWhat and where is riparian vegetation?
Vegetation is an important landscape element in any •watershed. The distribution of
vegetation species may be diverse and highly variable across the •watershed, but vegetation
communities can be described in more general terms as •well. The vegetation module
is designed to distinguish the primary plant communities
and identify their distribution •within the •watershed.
Because vegetation that grows along streams and other
waterways is often quite different from upland veg-
etation in terms of composition and degree of interac-
tion •with aquatic processes, vegetation communities
in the three environments (i.e., upland, riparian, and
•wetland) are characterized separately (Box 1).
In most •watersheds, the greatest portion of the
total land area consists of uplands. Despite the
distance from any waterbodies, upland vegetation
exerts important influences upon various •watershed
processes. For example, upland vegetation may
1) produce leaf litter that affects erosion, 2) modify
precipitation inputs through canopy interception, or
3) influence groundwater chemistry through plant
decomposition. Although the total area situated along
streams and •wetlands is normally much smaller, the
vegetation in these areas has a more direct effect upon
aquatic conditions, providing such functions as shade,
streambank reinforcement, and organic litter inputs,
among other functions.
Riparian vegetation consists of plants within the zone
of direct interaction between terrestrial and aquatic
environments (Swanson et al. 1982).
The riparian zone can be defined as the area where
1) vegetation growth is influenced by moisture from
the waterbody (e.g., wetland orfloodplain area), or
2) vegetation exerts a direct effect upon aquatic con-
ditions (e.g., contributes shade or leaf litter).
Because determining which vegetation exerts a direct
effect on aquatic conditions is a complicated task, the
analyst will probably need to make some simplifying
assumptions. A reasonable starting point to deter-
mine the area of riparian influence is to include all
vegetation that is influenced by the waterbody (#1
above) plus an additional width equivalent to the
height of the tallest plants. If using remote information
such as aerial photos, the analyst will probably need
to identify a fixed evaluation width along channels.
The primary focus of the Level 1 Vegetation assessment is to identify the primary vegeta-
tion types and plot their distribution across the •watershed. The assessment methods rely
largely upon interpretation of remote information, such as vegetation maps, aerial photos,
or satellite images. While the analyst is examining and categorizing vegetation types, land
use impacts may become apparent as •well.
It is important to realize that vegetation communities are dynamic due to natural plant
succession as •well as human-caused and natural disturbances. It may take some skill to
evaluate past or potential plant community composition based on a remote assessment of
existing conditions. The assessment of specific changes in vegetation functions, as •well as
their causes, •will benefit from close coordination •with other members of the assessment
•tation
page
VE-1
-------
team. In addition, the analyst may gain a preliminary sense of which functions the
various vegetation types will provide most effectively. However, a determination of
the relationship between vegetation function and specific land use impacts will require
further consideration via a Level 2 assessment. The following are examples of analyses
that would be performed in a Level 2 assessment:
• Assessing vegetation status to finer attributes (e.g., distinguishing tree size or density)
or at finer scales of spatial resolution such as the "site" scale (i.e., < Imi2 or 1.0 mi
of stream length).
• Assessing historical or potential vegetation conditions in detail.
• Assessing the specific land use practices that have created impacts (e.g., refining focus
from "logging" to "tractor logging within 200 feet of streams").
• Assessing the effectiveness of various vegetation types or conditions at providing
individual functions.
• Assessing changes in aquatic resources that have resulted from vegetation changes.
page
VE-2 Vegetation
-------
Vegetation Module Reference Table
Critical Questions
Information
Requirements
Level 1
Methods/Tools
Level 2
Methods/Tools
V1:
What are the primary vegetation
categories that exist in upland
areas?
V2:
What are the primary vegetation
categories that exist in riparian
areas?
V3:
What are the primary vegetation
categories that exist in wetland
areas?
V4:
Does existing upland, riparian,
or wetland vegetation
differ substantially from
historical conditions?
V5:
What are important functions of
upland vegetation relative to
watershed processes?
• Previous vegetation studies
• Vegetation maps, GIS data,
aerial photos
* Anecdotal information
• Same as for VI
* Floodplain surveys
* Local "sensitive" or "critical
areas" inventories
* Same as for VI
• NWI maps
* Soil surveys and hydric soils
lists
• Recent wetland delineations or
assessments
* Local sensitive or critical areas
inventories
• Same as for V1-V3 for present
conditions
* Land use map
* Historical vegetation maps
* Old aerial or oblique photos
• Old timber or stream survey
narratives
• Upland vegetation map pre-
pared for VI
* Anecdotal information
• Prepare upland vegetation
map from existing data
and aerial photos (recon-
naissance level)
• Prepare riparian/wetland
vegetation map from
existing data and aerial
photos (reconnaissance
level)
* Prepare riparian/wetland
vegetation map from
existing data and aerial
photos (reconnaissance
level)
• Document location and
approximate extent of
changes identified from
remote or historical sour-
ces (reconnaissance level)
• Develop preliminary list
of upland vegetation func-
tions
• Refine upland vegetation map
with further remote or field
investigation
* Focused assessment of special
upland plant species or com-
munities
• Refine riparian/wetland vegeta-
tion map with further remote
or field investigation
* Focused assessment of special
riparian plant species or com-
munities
* Refine riparian/wetland vegeta-
tion map with further remote
or field investigation
• Focused assessment of special
wetland plant species or com-
munities
• Quantitative assessment of his-
torical change that evaluates
the area of vegetation involved
and change in functional effec-
tiveness
• Reconstruct natural vegetation
disturbance history:
- flooding
- wildfire
- windthrow
- avalanche
- drought
• Numerous methods depending
on upland function; coordinate
with other analysts
•tation
page
VE-3
-------
Vegetation Module Reference Table (continued)
Critical Questions
Information
Requirements
Level 1
Methods/Tools
Level 2
Methods/Tools
V6:
What are important functions of
riparian vegetation relative to
watershed processes?
V7:
What are important functions
of wetland vegetation relative to
watershed processes?
V8:
What land use practices have
influenced or could influence
vegetation conditions and func-
tions?
• Riparian/wetland vegetation
map prepared for V2 and V3
• Anecdotal information
• Recent riparian assessments
• Riparian/wetland vegetation
map prepared for V2 and V3
• Anecdotal information
• NWI maps
• Soil surveys and hydric soils
lists
• Recent wetland delineations or
assessments
• Local sensitive or critical areas
inventories
• Anecdotal information
• Aerial photos
• Maps/CIS data
• Develop preliminary list
of riparian vegetation
functions
• Develop preliminary list
of wetland vegetation
functions
• Document location and
approximate extent of
changes identified from
remote or historical sour-
ces (reconnaissance level)
• Multi-function Proper Func-
tioning Condition assessment
• Wood recruitment potential
ratings approaches
• Wood recruitment modeling
• Shade assessment
• Wetland Evaluation Technique
• Hydrogeomorphic Classifica-
tion System
• Detailed analysis of individual
land use types
• Quantitative assessment of veg-
etation modification (change
in vegetation area or functions
provided)
page
VE-4
•tatton
-------
Level 1 Assessment
Step Chart
Data Requirements
Collect background vegetation Information
Select vegetation classification systems
Collect Information on existing vegetation
Identify and summarize changes
from historical conditions and other
land use Impacts
• Map of watershed with stream
network shown. The map should
preferably indicate either stream
order or any regulatory
categorization used locally (e.g.,
"Water Types" or "Stream Classes").
If GIS maps cannot be generated,
USGS topographic maps (1:24,000
scale) will be sufficient.
• Any existing vegetation reports and
maps that differentiate basic land
covers or define ecological zones.
• Floodplain surveys and maps
(FEMA or other source).
• Any wetland maps or recent
wetland delineations (e.g., NWI).
• Recent aerial photos or satellite
images of sufficient resolution for identifying vegetation types.
• Historical aerial photos or other data describing historical vegetation conditions (e.g.:
historical land survey notes, fish habitat surveys, or USFS forest distribution maps).
• A list or inventory of threatened, endangered, or sensitive plant species found in the
region (federal or state natural resource agencies).
• Soil surveys and hydric soils lists.
Products
• Form VI. Vegetation category summary
• Map VI. Upland vegetation
• Map V2. Riparian/wetland vegetation
• Map V3- Land use practices that affect vegetation
• Vegetation report
Upland
Riparian
Wetland
•tation
page
VE-5
-------
Procedure
The primary objectives of the Vegetation assessment are as follows:
• To characterize vegetation types that exist in upland areas of the watershed.
• To characterize vegetation types that exist in riparian and wetland areas of the watershed.
• To identify land uses or land use practices that have caused or contributed to changes
in vegetation.
• To identify watershed-related functions provided by vegetation in uplands, riparian
areas, and wetlands.
Step 1. Collect background vegetation information
Community
Resources
Box 2. A practical note
Although the "Data Requirements" section lists items that may be useful, the critical
elements are as follows:
• A watershed map that shows the stream network to
serve as a base map.
• Existing vegetation information describing current
or past vegetation in the watershed (Box 2). This
information could consist of maps, photos, site
surveys, plant studies, monitoring data, etc. (Box 3).
• Remote data resources, such as aerial photos or
satellite images.
• A list of rare or culturally significant plant species
present in the watershed (Box 4).
Box 3. Places to look for vegetation maps
• Tribal resource agencies
• BIA
• BLM
• USFS
• NRCS
• State or local agencies (particularly
forestry, wildlife, fisheries, or water
quality oriented)
• University or community libraries
Although the analyst may
be able to locate data
resources in libraries or on
the internet, a good short-
cut may be to contact an
individual who has a thor-
ough knowledge of the
available documentation
on resources in the
assessment area. Knowl-
edgeable persons often
include local land manag-
ers or agency employees
with long-term involvement
in resource issues. They
may be willing to loan
information the analyst can
review or reproduce.
page
VE-6
•tatton
-------
Box 4. Examples of culturally significant riparian and wetland species
Brown ash (Penobscot River basin, Penobscot Indian Nation, Maine): Riparian tree
species valued for traditional basket making.
Common reed (Cibecue Creek basin, White Mountain Apache, Arizona): A plant used
to make arrow shafts and ceremonial objects. Interviews with cultural advisors consis-
tently revealed that common reed used to be more abundant. Field trips with students
led to the identification of places where this plant grew. These areas became source
areas for transplants used in restoration projects.
Camas (Quinault River watershed, Quinault Nation, Washington): Wet-meadow plant
whose tuberous roots were a preferred native food source. Quinaults traditionally intro-
duced fire to maintain forest openings (camas prairies) in order to maintain preferred
growing conditions.
Step 2. Select vegetation classification systems
Separate classification systems will be needed for upland, riparian, and wetland areas,
although some consistency in approach among the three is desirable. Because there is no
single system that will be appropriate for all possible locations, the analyst must ultimately
choose or develop a useful system. Consider the following when choosing a vegetation
classification system:
• Start by reviewing any classification systems already in use. Use of an existing system
will facilitate input from individuals who may use these systems. It may be necessary
to either lump or sub-divide existing categories to provide an array of categories that
provides a balance between simplicity and detail.
• If no classification systems have been used within the watershed, it may be possible to
import a system being used for similar neighboring areas. Classification systems should
be based on the species composition where possible rather than on vegetation age or
size, which change over time.
• A good system will distinguish vegetation differences that correspond to important
functional differences. For instance, distinguishing riparian conifer forest from willow
vegetation is important because conifers can provide wood debris to the channel, while
shrubs cannot (Box 5).
•tation
page
VE-7
-------
Box 5. Notes on vegetation classification systems
Countless systems have been developed to characterize vegetation communities, some based on
gross differences (forest vs. desert), some distinguishing subtle differences in prevalence among the
same handful of species (see example below). The best classification system for use in the Vegeta-
tion module is the simplest system that captures important functional differences among vegetation
categories. The chosen system should also be mapable at the scale being used for other products.
Depending on the size and complexity of the watershed, a manageable system would result in
approximately 5-20 distinct vegetation categories.
The example below shows how vegetation can be classified at finer levels of resolution. Using a
finer scale system, such as the Plant Associations system on the right, will involve considerably
more complication and difficulty in delineating vegetation types accurately without extensive field
checking. The hypothetical watershed used to produce this table contains three Major Groups:
Alpine, Forest and Range vegetation. If each of these Major Groups can be broken into three sub-
categories (i.e., Dominant Vegetation Types), and each of these can be broken further into three
Plant Associations, that will result in nine Types and 27 Plant Associations. Thus, delineating at the
intermediate level is most practical for watershed scale assessments. It is also likely that functional
differences between the Plant Association categories are fairly minor.
Example of vegetation classification system
Overall level of detail
General
Major Groups
1 Alpine
2 Forest
3 Range
Intermediate
Dominant Vegetation Types
2a Spruce/fir
2b Lodgepole pine
— 2c Juniper
Specific
Plant Associations
~ 2bi Lodgepole/huckleberry
- 2bii Lodgepole/pine grass
— 2biii Lodgepole/rabbit brush
Applicability
for Vegetation
module:
Probably
too broad
May be OK
Probably
too detailed
• Ideally, each of the categories should be identifiable from remote data, such as aerial
photos. If category distinctions are too subtle, they may not be easily distinguishable
and could become cumbersome to map and use (Box 6).
Step 3. Collect information on existing vegetation
This step, which consists of collecting and compiling vegetation information, comprises
the bulk of new information generated within the Vegetation module.
page
VE-8
•tatton
-------
Box 6. A methodology note: characterization of upland vs. wetland and riparian vegetation
Although the steps for characterizing and mapping vegetation are essentially the same for upland, riparian,
and wetland vegetation, it may or may not be best to gather and process data simultaneously. The best
approach depends on the information sources available.
If the analyst will be using the same information source(s) to characterize upland, riparian, and wetland
vegetation (e.g., aerial photos for all), it may be most efficient to do all concurrently. On the other hand, if
the analyst will be using separate sources (e.g., existing vegatation maps for uplands vs. aerial photos for
riparian), it may be best to do the steps separately for each vegetation type. There might be intermediate
options as well, such as doing some of the steps together. For instance, field verification of upland and
riparian vegetation could probably be conducted during the same field visit.
Upland vegetation
a. Make or acquire a base map that will serve
as a draft upland vegetation map upon which
to collect notes and do preliminary mapping.
USGS topographic maps are a good option;
most already distinguish forested areas from non-
forested and agricultural areas.
b. Consult any existing information on vegetation.
Record information on the draft upland
vegetation map.
c. Inspect vegetation on aerial photos or other
remote data sources. If little existing vegetation
information is available, aerial photos may be the
primary source. Alternatively, even if vegetation
types have been previously mapped, photos may
be useful to verify accuracy (especially if existing
maps are out of date) or fill in blank areas. In
addition, the analyst may decide to sub-divide or
lump some vegetation categories that were used.
d. Record observations of land use impacts (Box 7).
e. Visit a sample of sites to validate or refine
boundaries. Depending on access and terrain, it
might be possible to review sizable areas from a
vehicle. Field inspection might reveal vegetation
differences that correspond with elevation, aspect,
Box 7. Recognition of vegetation
alteration on aerial photos
Clearing for agriculture - tilled soil or
smooth-appearing crop cover will be evident.
Logging - distinct patches without trees
likely indicate clearcut harvest; selective log-
ging will be less obvious, but areas of sparse
forest or yarding roads may be apparent.
Grazing - will be hard to see from photos if
dispersed; there may be visible trails along
fence-lines or bare spots where animals con-
gregate.
Fire - darkened ground inside burned areas;
edge of burn will be distinct, but irregularly-
shaped; may be able to see plant remnants,
such as burned trees.
Mining or quarries - pits will show up as
light-colored areas where rock is exposed;
hole may be visible when viewed in stereo;
underground mines may be identified by
piles of tailings, mine buildings, etc.
When confronted with photo interpretation
difficulties, it may be possible to find some-
one with local knowledge or excellent photo
skills to consult.
•tation
page
VE-9
-------
Erosion or landform type, and that information could be extrapolated to inaccessible areas
using topographic maps or aerial photos.
£ Fill in Form VI for each vegetation category and create the final upland vegetation
map (Map VI; Figure 1).
Figure 1. Sample Map V1. Upland vegetation
Spruce
fir forest
Rangeland
sagebrush
Agricultural
vegetation
Lodgepole
pine forest
Alpine
Riparian and wetland vegetation
a. Make or acquire a base map that will serve as the draft riparian/wetland vegetation
map. This map should show channels and wetlands, as well as roads and section
lines if possible, to make it easier to transfer information from maps or aerial
photos. The analyst may
Box 8. Locations of channels and wetlands need to do some addi'
tional research to locate
wetlands (Boxes 8 and 9).
b. The remaining procedure
is the same as for upland
areas (i.e., sub-steps b. - f,
above), with a few excep-
tions. For aerial photo
evaluation (sub-step c.),
the analyst will first need
to determine an evaluation
width (Box 1). For field
verification (sub-step e.),
USGS topographic maps generally provide good representation of the
channel system, although they may not show all of the smaller channels and
wetlands, especially in forested areas. Probably the best widely-available
source to provide a more complete inventory of wetland locations is the
National Wetlands Inventory (NWI). The NWI covers most of the United
States and uses the USFWS classification system (Cowardin et al. 1979),
described in Box 9. Likely places to find local NWI maps are county
planning agencies or the NRCS. There may also be independent wetland
studies, such as site-specific reports prepared for individual projects. In
some cases, aerial photos (especially large-scale or color) can be used to
help map small streams or wetlands.
page
VE-10
•tatton
-------
the analyst will probably find that inspection of riparian and wetland
areas will require more on-foot visits, rather than vehicle inspection.
Riparian and wetland vegetation information can be combined on one
map (Map V2; Figure 2).
Figure 2. Sample Map V2. Riparian/wetland vegetation
Box 9. Wetland definition
and classification
Cottonwood
stands
Alpine shrubs
Community
Resources
Historical
Conditions
Step 4. Identify and summarize changes from historical conditions
and other land use impacts
Changes in vegetation conditions can be determined
from aerial photos or other documentation.
Historical changes can be easily determined if they
are obvious and long-term, such as conversion to
agriculture or urban use (Box 10). It may be harder
to identify gradual changes in vegetation (e.g., from
long-term grazing or fire suppression) unless they
have already been documented.
Ongoing land use is easier to identify because it can be verified at any
time. For instance, rather than plotting individual clearcuts from logging
in the past decade, delineate the entire area managed for logging over a
longer period. These changes can be identified from aerial photos, field
visits, and local knowledge.
Because wetlands are regulated
under federal laws, a system was
needed to determine exactly which
criteria would distinguish wetlands
from uplands. The widely used defini-
tion of wetlands is based upon the
presence of three indicators: wetland
plants, hydric soils, and surface water
or soil saturation at some time within
the growing season (USAGE 1987).
The analyst will not need to make
wetland determinations for the Vege-
tation module but will likely use a sys-
tem for wetland classification. The
most common system for wetland
classification is one used by the NWI:
the USFWS or Cowardin system
(Cowardin et al. 1979). This system
indicates the water feature (marine,
riverine, etc.) and vegetation type (for-
est, shrub, etc.) of each wetland. This
system is well suited for use with the
Vegetation module, especially if NWI
inventory data are already available.
The second commonly used system
is the Hydrogeomorphic Classification
System (Smith et al. 1995), which
classifies wetlands on the basis of
hydrologic and landform setting. The
Hydrogeomorphic Classification Sys-
tem is well suited for determining the
role of wetlands in watershed proc-
esses, but it has the disadvantage of
not including any characterization of
vegetation.
•tatton
page
VE-11
-------
Box 10. Documenting historical vegetation modification
An example from the Cibecue Creek Watershed, White Mountain Apache Reservation, Arizona
In the 1950s and 1960s, the Cibecue Creek watershed was the subject of an extensive program to convert areas
of native pinyon-juniper woodlands, riparian cottonwoods, and other vegetation types to grass cover. The stated
goals of the project were to expand grazing resources, provide work for local Apache residents, and "possibly
increase water yield from the watershed." Thirty years later, accelerated erosion was more evident than were
water yield increases (which did not result), and the net benefits from this program were debatable. Despite the
apparent failure of this project to meet its stated goals, it did produce some information resources that may be
valuable for watershed assessment, such as pre-treatment vegetation and soils data. Also, the location and
extent of areas subjected to treatment were fairly well documented.
This vegetation conversion project differs from most other instances of large-scale vegetation conversion in that it
occurred relatively recently and was well documented. Such documentation is extremely valuable for assessing
the nature of impacts that have resulted from historical vegetation changes.
Box 11. Common ecosystem functions
attributed to vegetation
Upland vegetation
• Effects on erosion (soil cover, root strength,
organic matter production)
• Effects on hydrologic processes (evapo-
transpiration, snow accumulation and melt)
• Habitat and cover for biota
Riparian vegetation
• Influence on bank stability and channel
morphology
• Source of in-channel wood debris (mainly
important to physical channel processes)
• Source of litter and fine organic input (food
source for biota)
• Habitat for biota
• Moderation of water temperatures from
shade (Box 12; also covered in Water
Quality module)
Wetland vegetation
Sediment trapping
Source of wood debris for habitat
Nutrient uptake
Habitat and cover for biota
Assessment of land uses and practices is necessary
to determine causes for alteration of riparian areas,
removal of vegetation, and consequent effects on
streams and community resources. The assessment
procedure requires aerial photo interpretation and
limited field checking.
a. Identify the land use practices. Most activities
should have been identified in the Scoping
process, while observations from the aerial photo
analysis should provide supporting information
on the location and extent of land use practices.
b. Identify resulting impacts. This should
include a description of the changes to vegetation
species and communities. In many cases, specific
practices have changed over time, sometimes for
the better (e.g., restrictions on grazing or logging
along streams may have been implemented).
As possible, such changes should be noted and
considered in sub-step d.
c. Make a list of possible impacts to vegetation
functions. For Level 1 assessments, functions
will be inferred for each general vegetation type
(Box 11). Reductions in function will be
page
VE-12
•tatton
-------
Box 12. Assessment of riparian shade effects on water temperature
In some watersheds, shade from riparian vegetation plays a major role in maintaining cool stream temper-
atures required by cold water species, such as trout and certain amphibians. In other streams (large rivers
for example), the influence of riparian shade is minimal and upstream dams or water withdrawals are dom-
inant influences. Because of the variable importance of shade effects upon water temperatures, water
temperature issues are assessed in the Water Quality rather than Vegetation module. In watersheds
where riparian vegetation has an important influence, it may make sense for the Vegetation analyst to
undertake a widespread evaluation of riparian shade. Discussion between the Vegetation and Water Qual-
ity analysts will be helpful to determine an effective approach for the two modules.
assumed to correspond to the extent that the
original vegetation has been altered; however, this
assumption is not always accurate. Therefore,
the preliminary identification of impacts to
functions can provide hypotheses for further
Level 2 assessment.
d. Evaluate trends in recovery or restoration
(Box 13). Evaluate the long-term outlook
for recovery of impacted areas if the practices
continue or are discontinued.
Present results of the land use assessment.
Land use practices that affect vegetation should
be identified on Map V3 (Figure 3). More than
one map may be necessary if there are many land
use impacts that overlap for a given location.
Summarize results. Create a table or a narrative
to present at Synthesis that describes land use
practices, impacts on functions, and trends in
recovery or restoration.
Box 13. Recovery potential
from land use impacts
e.
f.
Natural recovery likely
• Logging
• Grazing
• Flood damage
• Fire
Restoration possible
• Conversion to agriculture
• Vegetation conversion
Restoration difficult
• Conversion to urban
• Floodplain or wetland
modification (e.g., diking,
filling, etc.)
•tation
page
VE-13
-------
Figures. Sample Map V3. Land use practices that affect vegetation
Dike
maintenance
Grazing
Step 5. Produce Vegetation report
In addition to the three maps and the vegetation summary forms, the Vegetation report
is an important end-product of this assessment. The report need not be elaborate or
lengthy but should document the following components:
• Assessment methodology:
- Vegetation classification systems chosen and why.
- Riparian assessment width used and justification.
- Primary information sources: vegetation studies, maps, aerial photos, field
investigation, etc.
• Results of the assessment:
- Distribution of upland, wetland, and riparian vegetation categories.
- The extent and severity of historical vegetation modification and ongoing land
use practices.
- Watershed functions provided by each vegetation category.
• Topics for Level 2 assessment; examples include the following:
- Trends in vegetation that result in changes in vegetation functions..
- Functions requiring further assessment (e.g., nutrient cycling, wildlife habitat).
- Issues involving rare or culturally significant plant species.
page
VE-14 Vegetation
-------
Level 2 Assessment
The information generated from a Level 1 assessment, such as the key vegetation types
in uplands, wetlands, and riparian areas across the watershed, can be useful for guiding
a Level 2 assessment (Table 1). A Level 1 assessment may not address certain priority
watershed issues or processes related to vegetation except in a broad or hypothetical way.
Synthesis brings the Vegetation assessment into a broader context of watershed issues
and provides an excellent forum to identify priority issues relating vegetation functions
to aquatic resources and watershed processes (Box 14).
Box 14. Examples of vegetation-related priority issues and hypotheses
suitable for Level 2 assessment
Although many potential priority issues are likely to arise during Synthesis, the analyst will
need to select a manageable number for assessment. Once priority issues have been chosen,
it will be valuable to develop hypotheses (i.e., testable statements that are narrower and
specifically focused on the role of vegetation). Hypotheses that involve issues covered by
other modules will require collaboration with other analysts.
Issue: Streambank erosion has increased.
Hypothesis: Grazing has reduced the abundance and vigor of bank-reinforcing vegetation.
Assessment Method: Land use or riparian functions.
Collaboration: Assessing bank erosion should involve the Channel analyst.
Issue: Waterfowl habitat has been reduced.
Hypotheses: Wetland filling for agricultural use in the last 100 years has resulted in reduced
waterfowl habitat.
Assessment Method: Historical change or wetland functions.
Collaboration: Community Resources analyst.
Issue: Grass species have been gradually replaced by juniper and sagebrush.
Hypothesis: Vegetation composition has changed substantially as a result of fire suppression.
Assessment Method: Historical change.
Collaboration: Community Resources analyst may be able to help assess the importance of
reduced forage.
Issue: Input of wood debris that creates trout habitat in streams has been reduced.
Hypothesis: In riparian areas that have been logged, there is less wood debris entering the
stream or available for recruitment.
Assessment Method: Evaluation of specific land use practices or riparian functions.
Collaboration: Aquatic Life analyst should be consulted to guide assessment of fish habitat.
•tation
page
VE-15
-------
The Level 2 assessment employs more focused assessment techniques to address more
specific issues (Table 1). Because the major task of the Level 1 assessment is vegetation
characterization, the first three critical questions will have been largely covered. It is
more likely that priority issues for Level 2 will fall within the topics covered by Critical
Questions 4-8: changes from historical conditions, vegetation functions, and effects of
individual land uses.
Table 1. Summary of Level 1 products and possible avenues for Level 2 assessment
Topic
Products from
Level 1 assessment
Considerations for Level 2 assessment
Types and locations of
primary vegetation
categories
Maps of vegetation categories
More effort may be required to improve the
resolution of vegetation category locations
using additional field effort or photo
interpretation.
Vegetation changes
from historical
conditions
Major changes noted on vege-
tation maps
Detailed analysis of historical changes may
be useful, especially if an understanding of
target conditions is necessary and undistur-
bed reference sites are not available.
Functions of upland,
riparian, and wetland
vegetation
Preliminary lists of functions for
each vegetation type
Analysis of individual functions and their
importance to ecological processes can be
valuable.
Effects of land use
practices on vegetation
Information on land use practi-
ces and changes in vegetation
Further analysis could be valuable to evalu-
ate land use effects and to identify changes
in practices necessary to improve vegetation
conditions or functions.
Because this module is designed for use across a very broad array of natural landscapes
and vegetation types, there is no single method that will be suitable for all Level 2 issues
and settings. Rather, this discussion provides an outline of the general steps and several
broad approaches to vegetation assessment. Many methods have been developed for use
in various parts of the United States. The analyst will need to choose from existing
methods or develop a method suitable for the vegetation issues at hand. For this reason,
the Level 2 assessment relies heavily on the skills and judgement of the analyst to identify
methods suitable for the local environment and adapt one of these for the local landscape
and issues identified.
page
VE-16
•tatton
-------
There are several general approaches that may be useful in evaluating the priority issues
of a Level 2 Vegetation assessment. The following section is designed to introduce these
approaches, to help the analyst determine which are best suited to the identified issues, and
to provide limited guidance on how to pursue them most effectively. The organization of
the general approaches follows the issues listed in Table 2.
Table 2. Methods available for Level 2 assessment
Issues
Critical
questions Information requirements
Level 2 methods/tools
Types and locations of
primary vegetation cate-
gories
V1-V3 Various remote and direct
sources: aerial photos,
maps, GIS, field surveys, etc.
Further investigation with aerial photos or field
visits
Detailed assessment of special habitat types
Vegetation changes from
historical conditions
V4 Any documentation of histori-
cal vegetation conditions.
Analysis of historical documentation (see Sedell
and Luchessa 1982, Platts et al. 1987)
Functions provided by
upland, riparian, or
wetland vegetation
V5-V7 Information on upland,
riparian, and wetland
functions. Information
requirements differ among
methods.
Upland functions:
• Various methods depending on upland
function; coordinate with other analysts
Riparian functions:
• Wood recruitment potential ratings (e.g., WFPB
1997, Watershed Professionals Network 1999)
and recruitment modeling (e.g., Van Sickle and
Gregory 1990)
• Multi-function Proper Functioning Condition
assessment (Prichard et al. 1998)
• Shade assessment; collaborate with Water
Quality analyst
Wetland functions:
• Wetland Evaluation Technique (Adamus 1991)
Hydrogeomorphic Approach (Smith et al. 1995)
Effects of individual
land use practices on
vegetation
V8 Information on specific land
use practices: information
from field investigation, aerial
photos, GIS, agencies, etc.
Various regionally-applicable methods
•tation
page
VE-17
-------
Evaluation of Historical Vegetation Changes
Method summary
Identify long-term changes in upland, riparian, or wetland vegetation using
documentation of historical conditions, such as old aerial photos, land survey notes, or
narratives.
Primary benefits
A characterization of historical conditions can be extremely helpful in understanding
long-term trends in resource conditions (e.g., "Is vegetation removal responsible for the
widening of streams observed over the last 50 years?"), as well as providing a detailed
target for restoration. The historical picture is particularly useful for environments that
have been substantially modified and thus lack relatively non-degraded locations to serve
as reference sites. Historical vegetation conditions can also be used to create targets for
the desired levels of functions or to evaluate the degree of change in present vegetation.
In addition, this approach is the only one likely to provide insight (though indirect) into
the vegetation-influencing role of natural disturbance agents (e.g., wildfire, beaver activity)
that have been diminished or are no longer active.
Limitations
The extent and reliability of documentation available to support such an assessment is
highly variable from place to place. Documentation of conditions prior to 1900 is likely
to be quite limited, which reduces the applicability of this approach in areas with a
long history of land modification. Another challenge is extrapolating information from
photos or descriptions, which are typically site-specific, to the landscape scale. One final
caution is that because historical descriptions are largely qualitative, their use is subject
to considerable interpretation. Levels of resolution and confidence may be inadequate to
satisfy all community members in contentious situations.
Resources needed
• Old aerial photos with coverage that may go back to the 1930s or 1940s.
• Old landscape photos.
• Old maps or land survey notes (land survey notes often include descriptions of
vegetation).
page
VE_18 Vegetation
-------
• Written or oral narratives of tribal elders or long-time residents.
• Field surveys (especially useful in areas where remnants of past vegetation, such as tree
stumps, persist).
• Any other historical documentation.
Other considerations
Practically speaking, a historical vegetation study should be undertaken only if 1) the types
of information generated will be valuable, and 2) a preliminary inventory indicates that
sufficient documentation is available to produce a satisfactory portrayal.
Although historical investigations are increasingly common, there is little documented
guidance available (see Table 2 for two references). To a large extent, the quality of the
product depends on the diligence of the analyst.
Evaluation of Upland, Riparian, or Wetland Vegetation Functions
Method summary
Evaluate the effectiveness of present vegetation at providing one or more key ecosystem
functions, such as streambank reinforcement or wildlife habitat. Ideally this can be done
using an existing methodology; however, in some situations, the analyst may choose to
modify an existing method to fit local conditions.
Primary benefits
Functions assessment has numerous advantages, particularly when an existing evaluation
tool is available. Application of a widely accepted method takes advantage of the
familiarity and confidence associated with the method. Methods that focus on one or
two key functions are likely to be more objective than are holistic methods (Box 15). A
function-based approach is best suited to an area in which a relatively unaltered vegetation
community exists to serve as a standard for comparison.
Limitations
The utility of an assessment that focuses on one or two individual functions depends
on choosing appropriate functions, such that other key functions are not overlooked. If
T r •
Vegetation
& VE-19
-------
Box 15. Two general approaches to functions assessment: individual function and holistic,
multi-function
Individual function assessments assess one or more functions directly by evaluating components of
the vegetation community that correspond with the levels of function provided. Ideally, such
methods are supported by a strong scientific understanding based upon studies that have defined
quantitative linkages between vegetation conditions and levels of function. The assessment of one
or several well-understood functions at the exclusion of others is often justified by the presumption
that vegetation conditions that provide assessed functions will also provide acceptable levels of
other functions not considered. Examples of this approach include watershed analysis methods
used in both Oregon (Watershed Professionals Network 1999) and Washington (WFPB 1997), both
of which evaluate only shade and wood debris input for riparian vegetation.
Holistic, multi-function assessments assess function levels on the basis of the similarity of existing
vegetation to a pre-determined "reference condition" assumed to provide acceptable levels of all
desired functions. Some methods of this type simply assume that if the vegetation contains all the
right components, the functions will follow, while others include a qualitative evaluation of various
individual functions, as in the Functional Checklist used to evaluate Proper Functioning Condition
(Prichard et al. 1998).
an existing assessment method is available, the relevance of the results depend on 1) the
effectiveness of the method, and 2) the suitability of the method to the site where it will
be used. Functions assessment may be poorly suited to the evaluation of lingering impacts
from conditions or practices that have been discontinued.
Resources needed
• Documentation of any existing assessment methods available.
• Consultation with individuals experienced in use of these methods.
• Maps, aerial photos, or other resources required by the method.
Other considerations
Identification of key functions is an important step. Box 11 in the "Level 1" section lists
several vegetation functions to consider, although there may be others important locally
that are not included.
Finding and choosing a suitable method is also critical, and it is worthwhile to check
with local experts first. If a suitable method cannot be found for a priority issue, check
page
VE-20
•tatton
-------
the library or internet to find methods used in other locations that could be modified.
Another option is to use a general, multi-function method, such as the Proper Functioning
Condition approach (Prichard et al. 1998).
Evaluation of Specific Land Use Practices
Method summary
In watersheds where several land use types are dominant, it may be useful to assess the
impacts of specific land uses individually. The assessment will rely on the same techniques
used for the historical change and function assessment approaches discussed previously.
The unique aspect of the land use specific approach is that it includes an in-depth
assessment of the specific land use practices involved to support detailed recommendations.
Primary benefits
This approach will be highly effective in watersheds or sub-basins where there is a single,
obvious, dominant land use practice occurring. This approach should be considered for
watersheds where information to support revising particular land use practices is desired.
Limitations
The focus on a single land use may increase the potential to miss important impacts of
secondary land uses or processes. Also, it may be hard to evaluate recent changes in
practices unless some time has passed.
Resources needed
• Aerial photos.
• Maps and GIS data of logged areas, grazing allotments, etc.
• Land use maps. Community
• Consultation with and information from land managers or agencies involved in the Resources
particular land use of interest:
- All land use types - tribal or county planning/zoning agencies.
- Forestry - forestry agencies or companies.
- Agriculture/grazing - NRCS.
T 7 •
Vegetation
& VE-21
-------
Other considerations
It is important to assess not just the location of practices but the extent of physical effects,
such as soil disturbance, vegetation damage, and changes in the prevalence of plant species.
It is also important to evaluate time trends, such as changes in practices over time or
recovery trends.
page
VE-22
•tatton
-------
References
Adamus, P. R. 1991. Wetland evaluation technique (WET). Volume I. U.S. Army
Corps of Engineers, Waterways Experiment Station, Technical Report WRP-
DE-01, Vicksburg, Mississippi.
Cowardin, L. M. 1979- Classification of wetlands and deepwater habitats of the United
States. U. S. Fish and Wildlife Service, Office of Biological Services, Washington,
D. C.
Platts, W S., and 12 co-authors. 1987- Methods for evaluating riparian habitats with
applications to management. U.S. Department of Agriculture Forest Service,
Intermountain Research Station, General Technical Report INT-221, Boise,
Idaho.
Prichard, D. and 8 co-authors. 1998. Riparian area management: process for assessing
proper functioning condition. U.S. Department of the Interior Bureau of Land
Management, Technical Report Service Center, 1737-9, Denver, Colorado.
Sedell, J. R., and K. J. Luchessa. 1982. Using the historical record as an aid to salmon
habitat enhancement. Pp. 210-223 in: N. B. Armantrout (ed.). Proceedings
of a symposium on acquisition and utilization of aquatic habitat inventory
information, Western Division, American Fisheries Society, Portland, Oregon.
Smith, R. D., A. Ammann., C. Bartoldus, and M. M. Brinson. 1995- An approach
for assessing wetland functions using hydrogeomorphic classification, reference
wetlands and functional indices. U.S. Army Corps of Engineers, Waterways
Experiment Station, Technical Report WRP-DE-9, Vicksburg, Mississippi.
Swanson, F. J., S. V Gregory, J. R. Sedell, and A. G. Campbell. 1982. Land-water
interactions: the riparian zone. Pp. 267-291 in: R. L. Edmonds (ed.). Analysis
of coniferous forest ecosystems in the western United States. Hutchinson Ross,
Stroudsburg Pennsylvania.
U.S. Army Corps of Engineers (USAGE). 1987- Corps of Engineers wetlands delineation
manual. USAGE, Waterways Experiment Station, Vicksburg, Mississippi.
T 7 •
Vegetation
& VE-23
-------
Van Sickle, ]., and S. V. Gregory. 1990. Modeling inputs of large woody debris to
streams from falling trees. Canadian Journal of Forest Research, 20:1593-1601.
Washington Forest Practices Board (WFPB). 1997- Standard methodology
for conducting watershed analysis, Version 4.0. Appendix D. Riparian
function assessment. Timber/Fish/Wildlife Agreement and WFPB, Olympia,
Washington.
Watershed Professionals Network. 1999- Oregon watershed assessment of aquatic
resources manual. Draft report prepared for the Governor's Watershed
Enhancement Board, Salem, Oregon.
page
VE_24 Vegetation
-------
Form V1. Vegetation category summary
Vegetation category:
Primary species:
Unique or culturally valuable plant species present:
Land use impacts:
Functions:
Field sites visited:
•tation
page
VE-25
-------
page
VE-26
•tatton
-------
Glossary
-------
303(d) List:
A list of streams, lakes, and estuaries where state water-quality standards are not met or where technology-
based controls are not sufficient to achieve standards.
Adsorption:
The retention of atoms, ions, or molecules on the surface of another substance.
Aggradation:
The accumulation of sediment, usually implying an increase in deposit thickness.
Aeration:
The act of mixing a liquid with air (oxygen).
Aerobic:
Able to live, grow, or take place only when free oxygen is present.
Alluvium:
Unconsolidated material (sediment) deposited by flowing water.
Alluvial fan:
A landscape feature whose surface is shaped like an open fan or a segment of a cone and is formed by the
accumulation of sediment and organic material deposited by flowing water.
Ammonification:
The production of ammonia from the decomposition of organic matter.
Anaerobic:
Able to live, grow, or take place where free oxygen is not present.
Anecdotal information:
Information based on descriptions of individual cases rather than on controlled studies.
Anoxic:
The total deprivation of oxygen.
Aquifer:
A natural underground layer of porous, water-bearing materials (sand, gravel) usually capable of yielding
a large amount or supply of water.
Basin:
(see Watershed)
Baseflow:
Groundwater discharge to the stream; the flow not accounted for by storm runoff.
Bedload:
Sediment carried along a channel bed by sliding, rolling, or bouncing.
Bedrock:
Solid rock that underlies the earth's surface.
Beneficial use:
Taken from Section 303(c)(2)(A) of the Clean Water Act and state statutes, these include municipal,
industrial, and domestic water supply; contact recreation; non-contact recreation; fish and wildlife; and
agriculture use (irrigation).
Benthic:
Of or pertaining to the bottom of a body of water.
Best management practice (BMP):
A method that has been determined to be an effective, practical means of preventing or reducing pollution
or protecting resources; generally applies to non-point sources of pollution.
Bioaccumulation:
The process by which a contaminant accumulates in the tissues of an organism.
Biochemical oxygen demand (BOD):
The amount of oxygen consumed by microorganisms (mainly bacteria) and by chemical reactions in the
process of degrading organic matter in water.
page
Glossary G-1
-------
Biota:
The animal and plant life of a given region.
Braided stream:
A channel pattern with multiple threads of streamflow.
Bulk density:
Mass per unit of volume.
Calcareous:
Of or containing calcium carbonate, calcium, or limestone.
Carbonaceous:
Of or containing carbon.
Cartographic:
Of or pertaining to maps.
Channel:
A stream or river bed; generally refers to the physical form where water commonly flows.
Channel morphology:
(see Morphology)
Channel response:
Changes in the shape or structure of a channel.
Channelization:
The act of straightening a stream; typically widens and deepens the stream as well to improve the flow
of water.
Chelation:
The joining together of metals (such as copper) with certain organic compounds.
Coarse sediment:
Particles that are typically considered gravel-sized and larger; generally transported as bedload.
Chemical oxygen demand (COD):
A measure of the oxygen-consuming capacity of inorganic and organic matter present in water; the
amount of oxygen consumed from a chemical oxidant in a specific test.
Coliform:
A group of bacteria found in the intestines of warm-blooded animals (including humans), also in plants,
soil, air, and water. Fecal coliforms are a specific class of bacteria that only inhabit the intestines of
warm-blooded animals. The presence of coliforms is an indication that the water is polluted and may
contain pathogenic organisms.
Colloidal:
Of or pertaining to very small, finely divided solids that do not dissolve and remain dispersed in a liquid
due to their small size and electrical charge.
Colluvium:
The soil and rock debris on a hillslope that has been transported from its original location.
Community resource:
An environmental asset that has important cultural, economic, or spiritual value for the people of the
region (e.g., medicinal herbs, drinking water, agricultural land, fish and wildlife).
Critical questions:
A tool used in the technical modules to help identify the watershed assessment methods that will address
the issues of concern.
Cumulative effects:
The combined environmental effects over time of multiple land use activities, typically in a watershed
area.
Degree day:
A rough measure estimating the amount of heat in a given area; it is defined as the difference between the
mean daily temperature and 65 degrees Fahrenheit.
G-2 Glossary
-------
Delivery potential:
The likelihood that a hazardous input will be transported to a community resource.
Denitrification:
The anaerobic biological reduction of nitrate to nitrogen gas.
Dichotomous key:
A system that classifies materials by separating choices into two categories.
Dissection frequency:
The density of channels in a specified area.
Dissection pattern:
The distribution of channels in a specified area.
Disturbance event:
An uncommon occurrence from a natural agent, such as floods, fires, or hurricanes, that has a significant
influence on ecosystems
Diurnal:
Daily
Dry ravel:
(see Ravel)
Ecoregion:
An area with a relatively uniform pattern of terrestrial and aquatic ecological systems.
Effluent:
Wastewater, treated or untreated, that flows out of a treatment plant, sewer, or industrial point source, such
as a pipe. Generally refers to wastes discharged into surface waters.
Eh:
The electrical potential required to transfer electrons from one compound or element (the oxidant) to
another compound or element (the reductant); the reduction-oxidation potential. Typically used as a
qualitative measure of the state of oxidation in water treatment systems.
Empirical:
Relying upon or gained from experiment or observation.
Entrenchment:
(see Incision)
Erosion:
The removal of sediment or rock from a point in the landscape.
Eutrophication:
The increase in the nutrient levels of a lake or other body of water; this usually causes an increase in the
growth of aquatic animal and plant life.
Evapotranspiration:
The release of water vapor into the atmosphere by the combination of direct evaporation and transpiration
by plants.
Fan:
(see Alluvial fan)
Fecal coliform:
(see Coliform)
Fine sediment:
Particles that are typically sand-sized and smaller; generally transported as washload.
Fixation:
(see Nitrogen fixation)
Floodplain:
A nearly level alluvial plain that borders a channel and is occasionally inundated by floods (unless artificially
protected). The landform is formed by sediment transport and deposition from flows over the streambank
and lateral movement of the stream.
Fluvial:
Of or pertaining to streams; produced by stream action.
page
Glossary G-3
-------
Functions:
The contribution of an ecosystem element, such as vegetation, to the natural working of the ecosystem.
Geomorphic channel type:
A stream reach or group of reaches that respond similarly to changes in landscape forming processes, such as
water runoff, erosion, and vegetation growth.
Geomorphic process:
A landscape altering system, such as water runoff or erosion, that influences the movement and shape of
the physical landscape.
Geomorphic responsiveness:
The degree to which a stream channel changes its morphology or behavior due to alterations in landscape
forming processes, such as water runoff, erosion, and vegetation growth.
Geomorphology:
The study of physical landscapes (landforms) and the processes that create and mold them.
Geographic information system (GIS):
A computer system designed for storing, manipulating, analyzing, and displaying data in a geographic
context, usually as maps.
Glacial:
Of or pertaining to distinctive processes and features produced by or derived from glaciers and ice sheets.
Gradient:
The slope or incline measured by the change in elevation over a specified length. Measurement units may
consist of either a dimensionless proportion (percentage) or an angle based on the 360-degree circumference
of a circle.
Groundwater:
The water found below the surface of the land and contained in the pore spaces of saturated geologic media
(sand, gravel). Groundwater is the source of water found in wells and springs.
Hazardous input:
Any element of the ecosystem that can affect a community resource (e.g., sediment, nutrients, heat)
Headwaters:
The upper watershed area where streams generally begin; typically consists of 1 st- and 2nd-order streams
Hillslope process:
(see Geomorphic process)
Hydrogeology:
The study of the interaction of groundwater and the surrounding soil and rock.
Hydro graph:
A graphical plot of streamflow data over time.
Hydrologic regime:
The system that describes the occurrence, distribution, and circulation of water on the earth and between
the atmosphere.
Hyeto graph:
A graphical plot of precipitation data over time.
Hypothesis:
An assumption that requires verification or proof.
Impervious surface:
A material that does not allow, or allows only with great difficulty, the infiltration of water.
Incision:
The downward cutting of a stream into the earth's surface.
Interception:
In hydrology, the accumulation of precipitation on vegetation and other above-ground surfaces and its
evaporation during and after a storm event.
Interdisciplinary:
Interaction between different branches of knowledge.
G-4 Glossary
-------
Interstitial space:
The matrix of air or liquid between sediment particles; pore space.
Isohyet:
A line on a map along which all points receive the same amount of precipitation.
Karst:
A landscape influenced by the dissolving of limestone or gypsum; usually characterized by caves, sinkholes,
and underground drainage.
Landfiorm:
Any physical, recognizable form or feature of the earth's surface having a characteristic shape and produced
by natural causes.
Landscape:
The traits, patterns, and structure of a specific geographic area, generally including its physical environment
and biological composition.
Land type:
A feature on the landscape with a generally uniform shape and set of physical characteristics; often created
by a single geomorphic process.
Leachate:
A liquid that results from water collecting contaminants as it trickles through waste material. Leaching
may occur in farming areas, feedlots, and landfills and may result in hazardous substances entering surface
water, groundwater, or soil.
Life history stage:
A portion of an organism's life with specific living requirements.
Loading:
(see Pollutant loading)
Loess:
Fine-grained material that has accumulated by wind deposition.
Low flow:
Minimum instantaneous streamflow during periods of low water runoff.
Macroinvertebrate:
A larger organism without a spinal column, such as an aquatic insect.
Mass wasting:
The dislodgment and downslope transport of earth material as a unit under direct gravitational stress.
The process includes slow displacements such as soil creep and rapid movements such as landslides and
avalanches.
Mainstem:
The primary, and generally largest, branch of a river.
Module:
(see Technical module)
Morphology:
The form and structure of an object.
National Pollutant Discharge Elimination System (NPDES):
A provision of the Clean Water Act that prohibits discharge of pollutants into waters of the United States
unless a special permit is issued by the EPA, a state, or a tribal government on the reservation.
Natural disturbance:
(see Disturbance event)
Natural storage:
(see Watershed storage)
Nitrogen fixation:
The biological or chemical process by which elemental nitrogen from the air is converted to organic or
available nitrogen.
page
Glossary G-5
-------
Non-point source:
Pollution sources that are diffuse and do not have a single point of origin or specific outlet. The
pollutants are generally carried off the land by water runoff during storms.
Organic litter:
Material derived from living plant organisms, such as leaves and branches.
Orthophoto:
A corrected and standardized aerial photo; generally at a scale of 1:24,000.
Oxidation:
Oxidation is the addition of oxygen, removal of hydrogen, or removal of electrons from an element
or compound.
Parent material:
(see Bedrock)
Pathogens:
Microorganisms, such as bacteria, viruses, or parasites, that can cause disease in humans, animals, and
plants.
Pathway analysis:
The exploration of the relationship between different forms or phases of a pollutant.
Peak flow:
Maximum instantaneous streamflow during periods of high water runoff.
Photosynthesis:
The manufacture by plants of carbohydrates and oxygen from carbon dioxide mediated by chlorophyll
in the presence of sunlight.
Physiographic:
The natural, physical form of the landscape.
Planar:
On a level plane; flat.
Point source:
A stationary location or fixed facility from which pollutants are discharged or emitted. Also, any single
identifiable source of pollution, such as a pipe, ditch, ship, ore pit, or factory smokestack.
Pollutant loading:
The quantity of a contaminant entering the environment (soil, water, or air); typically related to specific
land use practices.
Protozoa:
One-celled animals that are larger and more complex than bacteria.
Rainsplash:
The displacement of sediment by bombardment of raindrops.
Ravel:
The rolling or sloughing of sediment due to loss of cohesion in surface materials.
Reach:
(see Stream reach)
Reaeration:
(see Aeration)
Recharge:
The process by which precipitation seeps into the groundwater system.
Reduction:
The addition of hydrogen, removal of oxygen, or addition of electrons to an element or compound.
Reference condition:
A state of being governed primarily by natural environmental processes and subject to minimal human
impacts; a place that represents natural conditions for comparison purposes.
G-6 Glossary
-------
Refugia:
An isolated place of relative safety from danger and hardship; the only remaining high quality habitat
within an area.
Resource sensitivity:
The responsiveness or susceptibility of an environmental asset to hazardous inputs.
Respiration:
The process in which an organism uses oxygen for its life processes and gives off carbon dioxide.
Rill erosion:
The movement of sediment through one of the first and smallest channels formed by water runoff. The size
distinction is not formal but has generally been defined as narrower than 12 inches.
Riparian:
Areas adjacent to rivers and streams. These areas often have a high density, diversity, and productivity of
plant and animal species relative to nearby uplands.
Roughness element:
Materials or forms that provide frictional resistance to the flow of water; examples include boulders,
vegetation, and gravel bars.
Runoff:
That part of precipitation, snow melt, or irrigation water that runs off the land into streams or other
surface water.
Sediment:
A solid particle, generally derived from rocks and minerals, that is being transported or has been moved
from its place of origin.
Sediment budget:
An accounting of the sources, transport, and deposition of sediment in a watershed over time.
Sediment yield:
The amount of sediment passing a particular point in a watershed per unit of time.
Sheetwash erosion:
The movement of sediment by unchanneled, overland flow of water.
Sinuosity:
A measure of the number of turns or curves in a stream expressed as the stream length (wavelength) divided
by the radius of curvature.
Snow-water equivalent:
The amount of water contained in a given volume of snow.
Soil creep:
The slow downhill movement of the soil mantle that results from disturbance of the soil by freeze/thaw
processes, wetting or drying, or plastic deformation under the soil's own weight.
Spawning:
The process of bringing forth offspring for aquatic organisms, such as oysters, fish, or frogs.
Stakeholders:
Individuals or organizations with a direct personal, economic, legal, social, or cultural interest in the
watershed.
Stream gage:
An instrument to measure the volume of streamflow over time, generally reported in cubic feet per second
(cfs).
Stream order:
A stream classification system in which the headwater channel is of order 1, and when two channels of the
same order join, they create a channel of one higher order (e.g., 1 + 1=2; 1+2=2; 2+2=3; etc.).
Stream reach:
A continuous portion of a stream between two designated points.
Sub-basin:
A watershed that is subset of a larger watershed.
page
Glossary G-7
-------
Substrate:
The particles that constitute the bed of a channel.
Surface water:
All water naturally open to the atmosphere, such as rivers, lakes, reservoirs, ponds, streams, estuaries,
and springs.
Suspended sediment:
Sediment carried within the water column of a stream.
Technical module:
A section of this document that provides guidance on conducting a science-based assessment on a set
of community resources or watershed processes.
Terrace:
A low-gradient surface formed by fluvial aggradation or erosion when the stream flowed at a higher
elevation in the landscape. The term usually implies that the surface is rarely, if ever, inundated by
floods in the current climate.
Total Maximum Daily Load (TMDL):
Generally refers to plans under the Clean Water Act that limit the amount of pollutant discharge
over time.
Topography:
The relative positions and elevations of the landscape that describe the configuration of its surface.
Transpiration:
The process by which water vapor is released to the atmosphere by living plants.
Tree throw:
The displacement of sediment held by the roots of a toppling tree; uprooting.
Trophic level:
A description of community structure based on the relationship between the production,
consumption, and decomposition of energy (food) by organisms. Primary producers such as algae,
herbivores such as deer, and carnivores such as wolves represent three different trophic levels.
Total suspended sediment (TSS):
(see Suspended sediment)
Turbidity:
The cloudy appearance of water caused by the presence of suspended and colloidal matter. Turbidity
indicates the clarity of water and is an optical property of the water based on the amount of light
reflected by suspended particles.
Unit pollutant loading rate:
(see Pollutant loading)
Upland:
An area of the terrestrial environment that does not have direct interaction with surface waters.
Volatilization:
The process of transferring a chemical from a liquid phase to a gas phase.
Washload:
Sediment carried in suspension by stream flow and that is of sizes not represented in the bed material.
Water budget:
A summation of inputs, outputs, and net changes to a water resource system over a period of time.
Waterbody:
Any type of surface water, such as a stream, lake, or wetland.
Water quality criteria:
Levels of water quality expected to render a body of water suitable for its designated use. Criteria
are based on specific levels of pollutants that would make the water harmful if used for drinking,
swimming, farming, fish production, industrial processes, or other designated use.
G-8 Glossary
-------
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.
Watershed:
The land area that drains into a stream; an area of land that contributes water runoff to one specific
delivery point (same as catchment, drainage, or basin).
Watershed approach:
A coordinated framework for environmental management that focuses public and private efforts on the
highest priority problems within hydrologically defined geographic areas taking into consideration both
ground and surface water flow.
Watershed process:
A natural system of interactions in the environment (e.g., water movement, erosion, nutrient cycling).
Watershed storage:
The capacity of an area to store precipitation in the snowpack, lakes, wetlands, and groundwater.
Wellhead protection area:
A protected surface and subsurface zone surrounding a well or well field that supplies a public water system
and through which contaminants could likely reach well water.
Wood debris:
Large pieces of organic matter, such as tree trunks and branches. No formal size distinction exists, but
pieces are generally greater than 3 meters in length and 10 cm in diameter.
page
Glossary G-9
-------
G-10
Glossary
------- |