September 20(
Watershed Analysis
and Management (WAM)
Guide for Tribes
EPA Watershed
Analysis and
Management Project
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Foreword
The Watershed Approach provides a unique and effective way to assess the environment,
identify problems, establish priorities for preservation or restoration, and implement
solutions.
The Environmental Protection Agency's (EPAs) Office of Wetlands, Oceans, and
Watersheds (OWOW) and the American Indian Environmental Office (AIEO) have
collaborated on a joint project to develop a comprehensive Watershed Analysis and
Management (WAM) methodology that addresses Tribal and State watershed management
issues. The objective is to produce a customer-tailored watershed analysis and management
framework that includes geographic-specific analytical assessment methods and application
techniques for addressing a wide range of environmental issues. The goal is to develop
a well-defined process that recognizes the explicit objectives of multiple stakeholders and
results in watershed management plans that reflect cultural values and consider economic
impacts and critical environmental resources. Typical problems addressed by the WAM
approach include the impact of timber operations on erosion, water quality, and fish
habitat and the impacts of various land use plans on pollutant runoff.
While each watershed area is unique and has a distinctive set of issues, a consistent
approach can be used to ensure credible and defensible evaluations. The WAM approach
utilizes five steps that can be applied to all watersheds: Scoping (identify issues and
stakeholders); Watershed Assessment (acquire and analyze data); Synthesis (integrate results
of the assessment); Management Solutions (develop options for improving conditions); and
Adaptive Management (monitor conditions and modify plans).
The WAM process is also sufficiently flexible to accommodate varying levels of community
participation, technical assessment, and management plan development. This guide
outlines two general levels of watershed assessment. A Level 1 assessment involves specific
guidelines, tools, and methods to characterize watershed conditions based primarily on
existing information. This level of analysis provides a rapid means to assess a watershed and
establish priorities. For example, a Level 1 assessment would be an effective way to address
Unified Watershed Assessments (UWAs) under the Clean Water Action Plan. A Level 2
assessment utilizes more quantitative tools and methods involving the acquisition of field
data and use of detailed scientific analyses. This level of assessment would be utilized
for the comprehensive analysis of a watershed where major economic or environmental
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issues are at stake, such as TMDLs. The Watershed Assessment is divided into
a series of technical modules (Community Resources, Aquatic Life, Water Quality,
Historical Conditions, Hydrology, Channel, Erosion, and Vegetation) that can be used
independently and modified as necessary to meet the specific goals of the Tribe, State,
or local community.
The WAM project has been funded by a system development grant, under OWOW,
with the Pacific Watershed Institute, concurrent with pilot applications of the approach,
through AIEO grants, by tribes representing different ecological environments, project
objectives, and regulatory issues. The four Tribes are the Penobscot Nation (Maine), the
Prairie Band of the Potawatomi (Kansas), the White Mountain Apache Tribe (Arizona),
and the Quinault Indian Nation (Washington). Each Tribal pilot is implementing a
WAM process that addresses issues within its watershed at a level of analysis appropriate
to their needs and the available resources. The development of the WAM system and
pilot applications began in 1997 and will be completed in 2000. A related effort
using a Watershed Approach to TMDLs is being undertaken with the Navajo Nation
in Window Rock, Arizona.
The WAM team assisted in development and training for the Clean Water Action Plan,
UWA Nationwide Tribal Workshops held in 1999. The WAM team also participated in
watershed information transfer through National Conferences and Workshops ranging
from Tribal environmental planning through community level Smart Growth issues.
Plans for 2000 and beyond include training workshops, participation in watershed
leadership and mentoring programs, additional community and Tribal applications, and
information transfer through participation in related conferences and workshops. The
Tribal pilots are a continuing key resource for all WAM efforts.
For additional information contact Martin Brossman at the EPA (202) 566-1210 or
brossman.martin@epa.gov.
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Acknowledgements
Contributors to this guide include (in alphabetical order):
Dr. Mike Barbour
Jean Caldwell
Dr. Shulin Chen
Tammis Coffin
Jim Currie
Cygnia Freeland
Karen Welch
Joanne Greenberg
Christy Parker Nock
Dr. Patricia Olson
Tom Ostrom
Dave Somers
E. Steven Toth
Curt Veldhuisen
Layout and Graphics: 4 Point Design
This project was funded by a generous grant from the Environmental Protection Agency's
(EPA's) Office of Wetlands, Oceans, and Watersheds. Martin Brossman was invaluable in
providing guidance and encouragement on the project. The tribal pilot projects involving
the Penobscot Indian Nation (Maine), Potawatomi Tribe (Kansas), White Mountain
Apache Tribe (Arizona), and Quinault Indian Nation (Washington) provided excellent
examples for applying watershed analysis in different regions of the country and using
different approaches. These pilot projects were funded by a generous grant from the EPA's
American Indian Environmental Office.
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 the WAM Guide and/or the Pacific Watershed Institute please
contact:
Dave Somers
E. Steven Toth Pacific Watershed Institute
321 30th Avenue 24406 132nd Street Southeast
Seattle, WA 98122 Monroe, WA 98272
206-860-7480 306-794-8927
thomtoth@nwlink.com somers@dsomers.seanet.com
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Table of Contents
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V-l=<
Introduction
The Watershed Analysis and Management Process
Overview
Step 1: Scoping
Step 2: Watershed Assessment
Step 3: Synthesis
Step 4: Management Solutions
Step 5: Adaptive Management
Technical Modules
Community Resources
Aquatic Life
Water Quality
Historical Conditions
Hydrology
Channel
Erosion
Vegetation
Glossary
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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
TIA Total impervious area
TMDL Total Maximum Daily Load
TSS Total suspended solids
USAGE U.S. Army Corps of Engineers
USDA U.S. Department of Agriculture
USDI U.S. Department of the Interior
USFS U.S. Department of Agriculture Forest Service
USFWS U.S. Fish and Wildlife Service
USGS U.S. Geological Survey
WAM Watershed Analysis and Management
WEPP Water Erosion Prediction Procedure
WFPB Washington Forest Practices Board
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Introduction
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"Go slowly. Respect and listen to the streams and the land.
They will tell you what to do."
-Bernice Endfield, White Mountain Apache Tribal elder
Native Americans have distinctive cultural and spiritual connections to the land. The
collective wisdom of elders and ancestors has allowed them to carefully use and manage
Box1. WhatisWAM?
The WAM process is
a well-defined, yet
flexible method to
credibly examine and
develop solutions to
watershed problems.
Box 2. WAM objectives
the land for centuries. Unfortunately, discussions of land
management and development have often neglected or
forgotten their perspective. Many landscapes have been
altered and often do not ade-
quately support resources impor-
tant to tribes. These resources
are a vital part of tribal culture
and need to be considered more
directly. The Watershed Analysis
and Management (WAM) process outlined in this guide is one
tool that can be used to heal and restore the bonds between the
community and the land.
WAM offers tribes a framework to identify key environmental
issues and develop effective management solutions that protect
and restore valued resources (Boxes 1 and 2). The WAM
process uses an ecosystem approach in
which information from various scientific
disciplines is collected to comprehensively
evaluate water-related resources within a
watershed (Figure 1). The assessment
generally relies on readily available
environmental information from maps,
reports, and existing databases. Com-
bining modern watershed assessment
techniques with indigenous knowledge
produces valuable insights about historical
conditions, resource trends, and restora-
tion opportunities (Box 3). Credible and
effective management plans are developed
based on the comprehensive assessment.
WAM is a flexible process that can be
adapted to address a broad range of local
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
Figure 1. A watershed approach focuses on addressing
water resource issues by river basins
Watershed
boundary
Flood plain
Stream
channel
Introduction
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Box 3. Use of indigenous knowledge
The Penobscot Nation, Maine
Place names in the Penobscot language often correspond to landscape characteristics. Ancient place
names offer clues about the nature and extent of the glacial deposits that once lined the shores
before the gravel and sand were dug away to build roads. Place names help describe the waterfalls
and rapids that have since been dynamited or flooded by hydropower dams. Place names in this
watershed may also be useful for identifying historical locations of salmon spawning streams, valued
plant communities, and important spiritual sites.
The White Mountain Apache Tribe, Arizona
The WAM project manager worked closely with tribal elders and high school students on the
reservation to identify and restore native plants and animals at important cultural sites in the Cibecue
Creek watershed. Cultural advisors conducted field trips to identify vegetation historically present
along streams, springs, and wetlands, and the tribal fisheries program collaborated on the examination
of fish populations.
issues and watershed conditions (Box 4). WAM can also incorporate and enhance exist-
ing tribal environmental programs to use funds and personnel most efficiently. Millions
of dollars are spent to evaluate aquatic resources, conduct monitoring programs, and
develop restoration plans, yet these projects are rarely considered collectively. The tools
provided in the WAM process help ensure that high quality information is collected to
develop and prioritize projects that will effectively improve the health of the ecosystem
and the community.
Watershed management is a long-term process that requires a strong commitment. The
benefits include not only the restoration of the environment, but also healing of the
community. A watershed is more than just a placeit represents a community with
important ideas and values about using and protecting their environment.
Box 4. Examples of issues that can be addressed by WAM
Clean, safe drinking water
Condition of aquatic ecosystems
Point and non-point source pollution on a watershed scale
Land management effects on endangered and threatened species
Environmental impact statements
Beneficial use-based water quality standards
Total Maximum Daily Load (TMDL) plans to address water quality impairment
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Introduction
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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 between 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 WAM team is optimally led by tribal and community representatives who have interest
in watershed issues. Environmental professionals are helpful to implement the assessment
and carefully evaluate issues in a credible and defensible manner. Tribal elders and other
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 tribe will need to determine the best
Introduction
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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.
I 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.
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Introduction
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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 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
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Levels of Assessment
Box 6. Logic tracking
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
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.
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.
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Introduction
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WAM Process
The WAM approach consists of five steps that lead the WAM team 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 tribe.
Scoping
A
In the Scoping step, the
tribe 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 3
SCOPING
Determine watershed issues
and project goals
Evaluate community participation
Determine scope of assessment
WATERSHED ASSESSMENT
Apply technical modules
Promote interaction among
analysts
( Step 3 )
SYNTHESIS
Combine information from modules
Summarize key findings
C
MANAGEMENT SOLUTIONS
Develop management options
Create management plan
( StepS )
ADAPTIVE MANAGEMENT
Monitor watershed conditions
Evaluate management plan
Introduction
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Box 7.Technical modules
Resource modules identify important resources and
determine their sensitivity 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
participants to look beyond their
in individual modules.
Synthesis
.^»
The objective of Syn-
thesis is to combine
knowledge gained
about individual com-
ponents 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 tribal
and other community representatives who
participated in Scoping. Synthesis requires
respective areas of expertise and the analyses conducted
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 systemin 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
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Introduction
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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.
Introduction
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Penobscot Indian Nation WAM Case Study
The Penobscot Indian Nation faces problems with fish passage, fish habitat, and water
quality in the Penobscot River Basin. Fish consumption advisories interfere with treaty
reserved fishing rights. Dams and point source discharges are known to affect tribal
resources, and non-point sources of pollution need to be investigated.
Why We Used WAM
The tribe chose to participate in WAM because we knew that an ecosystem approach is
the only way to begin addressing cumulative impacts to the aquatic ecosystem. We also
chose to use WAM to develop the basis for defensible and scientifically credible tribal
water quality standards.
Box 8. Penobscot Nation WAM summary
WAM steps
Used in Penobscot WAM
1. Scoping
Identify stakeholders No, internal only
Collect background information Yes
Develop critical questions Yes
2. Watershed Assessment
Resource modules
Community Resources Yes, LeveM
Water Quality Yes, LeveM
Aquatic Life Yes, Level 1
Historical Conditions No
Process modules
Channel Yes, modified
Vegetation No
Erosion No
Hydrology No
3. Synthesis Yes
4. Management Solutions No, future step
5. Adaptive Management No, future step
Our Application of WAM
The Penobscot WAM only used the first
three steps of the five-step process to
cover an entire river basin. WAM is not
usually applied to such a large geographic
area. Ours was a Level 1 characterization
because we chose to rely on data from
existing projects and because we modified
the Scoping and Watershed Assessment
steps to complete the project with existing
staff (Box 8).
Step 1: Scoping
We chose to rely on internal stakeholders
in the tribal community rather than
involving external groups. It was necessary
to clarify tribal concerns and examine
the condition of tribal resources before
opening the planning process to other
page
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Introduction
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groups. We had concerns about what the term "stakeholder" meant in terms of tribal
sovereignty and preferred the term "cooperators." Obtaining background information on
the condition of the resources in the Penobscot River Basin is a large and almost endless
task. Developing maps to show this information was the most time-consuming part of
the WAM project. Following the WAM guidance, we stated our project goals in the form
of four questions:
What documentation exists for tribal beneficial uses of water resources within the
Penobscot River Basin?
What data are available on the condition of these resources?
What data are available on the watershed processes that may affect these resources?
What data are available on the human activities that may affect these resources?
Step 2: Watershed Assessment
We proceeded to characterize the state of knowledge of tribal beneficial uses, water quality,
and fisheries resources, rather than conduct a full assessment using technical modules. A
watershed assessment is not complete if it focuses on watershed resources alone. We found
that it would be necessary to examine at least one watershed process, so we adapted the
Channel module for our use and added a consulting geologist to our team. This turned out
to be one of the most valuable aspects of the entire project.
Step 3: Synthesis
Synthesis was the most interesting part of initial results in the form of WAM. The four
members of the assessment team came together to share initial results in the form of
maps and to answer each other's questions. We made new connections among watershed
resources and geological processes that affect them. For example, we learned that glacial
deposits of suitable "home rocks" for adult salmon are located in the part of the river
that Atlantic salmon can no longer reach due to removal of fish passage by hydroelectric
projects. We also learned that certain glacial deposits (eskers) were associated with
groundwater inflows that provide cold water refugia for salmon. We learned that much
geological information is contained in Penobscot language place names.
Introduction
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Challenges
The challenges we faced in our WAM project mainly related to our unfamiliarity with
WAM as a planning process. We found it to be more complex and involved than
anticipated, and we took steps to simplify and tailor the process to fit our needs. It was
necessary to scale back our expectations and settle for a characterization of watershed
conditions rather than an analysis of cumulative impacts. Initially, we thought WAM
could be done with one staff person before we learned that a team approach was
necessary. It was a challenge to ask specialists to work together cooperatively in a
different manner than they were accustomed to. Dedicating staff time to long-range
planning when daily projects needed attention was challenging but proved to be of great
value. We had to find a balance between meeting our own planning needs and fulfilling
our responsibility as a pilot project. Mapping took far more time than anticipated and
became the main focus of the project.
Accomplishments
We gained a great deal from participating in the WAM pilot project. It gave us the
opportunity to conduct long-term planning and complete base maps that we had needed
for quite some time. The interdisciplinary process yielded valuable insights. WAM
was made flexible enough to accommodate our needs yet remained rigorous enough
to ask us to examine aspects of the watershed that we had not identified as a priority.
Participating in WAM compelled us to find a geologist to work with, and she added a
great deal to our planning and learning process.
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The Watershed Analysis
and Management Process
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Overview
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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 tribal 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.
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 initiated by tribes or agencies 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 land within and outside of reservation
boundaries.
Figure 1. WAM five-step process
C steP1 3
SCOPING
Determine watershed issues
and project goals
Evaluate community participation
Determine scope of assessment
WATERSHED ASSESSMENT
Apply technical modules
Promote interaction among
analysts
C steP 3 J
SYNTHESIS
Combine information from modules
Summarize key findings
C
MANAGEMENT SOLUTIONS
Develop management options
Create management plan
ADAPTIVE MANAGEMENT
Monitor watershed conditions
Evaluate management plan
Overview
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Box 1. Definitions for terms commonly used in the WAM guide
Community resource: an environmental asset that has important cultural, eco-
nomic, or spiritual value for the people of the region (e.g., medicinal herbs, 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).
Scoping
The primary purpose of Scoping is to help determine
the specific goals of the WAM process. Ideally,
the tribe together with community representatives will
decide on the WAM objectives. 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 provides guidance on choosing the appropriate scope and level
of detail for the Watershed Assessment, with consideration of financial and personnel
resources. The Scoping 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 the tribe, community representatives,
and the technical team is encouraged to make sure that as the number of modules
or critical questions is reduced, the interdisciplinary and comprehensive aspect of the
assessment is not significantly diminished.
page
Overview
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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.
The Watershed Assessment section provides guidance on managing an
interdisciplinary technical team and conducting the assessment. The
Technical Modules section consists of eight modules that provide methods
for evaluating various aspects of the ecosystem. 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). Box 2. Combining modules
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 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
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
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Box 3. Potential objectives of a Level 1 assessment
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.
Summarize general watershed characteristics
Describe key watershed issues
Identify important gaps in information
Prioritize further assessment or monitoring needs
Box 4. Summary of possible Level 1 technical module products
Resource Modules
Process Modules
Community Resources
Location 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
Location 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
Hydrology
Climate summary
Characterization of runoff processes
Characterization of stream runoff
Potential land use impacts (dams, dikes, urban and rural
development, irrigation, and 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
Overview
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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,
Box 5. Potential objectives of a Level 2 assessment
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
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.
Box 6. Icons 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 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.
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.
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
Overview
page
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interaction among different scientific disciplines to provide a more comprehensive
picture of the watershed. This part of the WAM process can also provide 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 a tribe and local, state, or federal agencies may
have the ability to implement some management options on their own.
Adaptive Management
Box 7. Monitoring objectives
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 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
Overview
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Step i: Scoping
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Introduction
Through the Scoping process, the tribe defines the direction of the assessment and
determines who will participate in the WAM process. Scoping will help organize leadership
for the Watershed Assessment and clarify project management needs. Tribes can use the
Scoping process to determine both short- and long-term project goals by evaluating the
complexity of watershed issues, community participation, staff availability, and financial
resources. Starting slowly and simply with basic watershed information can help build a
strong foundation for further assessment and watershed improvements.
This section describes various issues that need to be considered in Scoping. The first step
is an internal Scoping process to help the tribe determine WAM objectives. The tribal
objectives can then be evaluated in the context of other community needs to help prioritize
watershed issues and identify project goals. Scoping is by nature an iterative process that
may require revisiting certain decisions or considering new issues. Thus, the order in which
the issues are considered is less important than the fact that they are explicitly discussed.
Scoping Process
Step Chart
Procedure
The objectives of the Scoping step are as follows:
To identify leadership for the WAM process.
To determine key watershed issues.
To establish WAM project goals.
To evaluate community participation.
To determine staff and funding needs.
To determine which modules and level of
assessment address the project goals.
Determine tribal WAM goals
Plan and conduct Scoping meeting
Refine final scope of
Watershed Assessment
Step 1 . Determine tribal WAM goals
Identify leadership for the WAM process
The decision to broadly examine water-related resources can be initiated by any number
of people. The leadership for the process may come from one individual or a larger
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group or committee. A tribal council may be the authority for ultimately approving the
WAM process, but the environmental program director will often be responsible for project
management. It will be important to determine the lines of responsibility and authority
for managing the project.
The WAM process can be an informal project involving just a few people or a more
intricate process that includes many committees and various interest groups. If a larger
WAM process is being initiated, it will important to identify staff and funding resources to
ensure an effective management process. A project leader may be needed to organize and
manage the three main groups responsible for conducting the WAM project:
Box1. 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 tribal members, 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.
Scoping participants.
Watershed Assessment team members.
Watershed management team members.
Identify watershed issues
project goals
A WAM project is typically initiated in
response to a general watershed-scale issue,
such as the listing of an endangered species
or water quality impairment. The tribe
should define these issues as specifically
as possible to determine reasonable project
goals. Both short- and long-term goals for
the WAM process may need to be discussed
(Boxl).
The following questions may help guide the
discovery of watershed issues:
What are the important resources
within the community?
Where are these resources located in the
watershed?
What are the potential land use impacts
to these resources?
Scoping
-------
The watershed issues identified may be recorded in Form SCI (Figure 1). Table 1 provides
examples of possible watershed issues by land use.
The determination of WAM project goals is an iterative process. The issues and goals
identified in this step may need to be redefined if the tribe chooses to open the process to
Figure 1. Sample Form SC1. List of watershed issues
Watershed Issue
Affected Resources
Potential Causes
1. Fish can no longer be eaten
because of high levels of
pollutants
Bass, salmon, trout
Food and cultural resources
important to tribes
Community recreation
Pulp and paper mill effluent
Stormwater runoff
Naturally high mercury levels
2. Bank erosion and channel
entrenchment limit land
productivity and degrade water
quality
Loss of farmland
Damage to county road
Loss of tribal cultural sites
Loss of forested floodplain
habitat
Reduction in stream habitat
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.
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the larger community or if available resources (time, staff, funding) will be insufficient
to meet the goals. These issues are revisited at the end of the Scoping process (Step 3).
Identify assessment area and scale
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 riverine
ecosystems. 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 (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
Scoping
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Defining the appropriate scale at which to conduct the assessment can be a difficult issue
to address. Site-specific land use practices may be considered and evaluated as part of the
Watershed Assessment; however, conducting an assessment at this scale (typically a map
or a photo scale of 1:5,000 or smaller) is typically not feasible or desirable 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 for addressing
local issues within the watershed. A scale 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.
Identify assessment team
The assessment team comprises environmental professionals who will use the technical
modules or other methods to assess the watershed. As the issues to be addressed in
the Watershed Assessment begin to crystallize, it may be helpful to start thinking about
members to participate on the assessment team. The team may be composed of tribal
natural resource department staff, or for more complex issues, such as those addressed in a
Level 2 assessment, specialists may be used. (Table 2). The assessment team membership
will be reevaluated during the Scoping meeting.
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
Tribal Historian, Anthropologist, or Archaeologist
Aquatic or Wildlife Biologist
Aquatic Ecologist, Environmental Engineer,
Aquatic Biologist, Water Chemist, or Hydrologist
Tribal Historian, or Librarian
Hydrologist or Environmental Engineer
Geomorphologist, Hydrologist, or Geologist
Geologist, Geotechnical Specialist, Soil Scientist,
or Geomorphologist
Ecologist or Botanist
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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 generated in the Scoping process and
Watershed Assessment.
Electronic mail to easily communicate with Scoping participants and assessment and
management team members.
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.
Consider resource needs and funding
The time frame and resource needs for conducting the WAM process will depend on
the watershed issues and project goals identified and on the scale of the assessment.
The WAM process is designed with two levels of assessment that can be used to
evaluate watershed issues in a few months to several years, but the actual time and costs
associated with the project 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 in the assessment.
Box 3. Potential funding needs
Funding should be considered for
the following project elements:
Project management.
Technical assistance.
Assessment materials.
Document production.
Field monitoring equipment.
GIS support.
WAM outlines a framework for evaluating environmental
problems and developing effective management solutions
that should increase opportunities for funding (Box 3).
Involving the local community, understanding ecological
processes, and using defensible, science-based assessment are
important elements for many state and federal grants. Tribes
may also choose to rely on in-kind support from public
agencies or citizen groups through cooperative projects, cost-
share programs, or technical assistance, rather than seeking
additional grants (Box 4).
Scoping
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Box 4. Using cooperators to support WAM
Example from the Quinault River watershed
The Quinault Indian Nation in Washington used a number of cooperators from federal and
tribal agencies to complete a watershed assessment for the Quinault River watershed.
Representatives from the USGS, U.S. Bureau of Reclamation, Olympic National Park,
Olympic National Forest, U.S. Bureau of Indian Affairs (BIA), and Northwest Indian
Fisheries Commission served as team members and provided technical assistance.
Example from the Cibecue Creek watershed
The White Mountain Apache Tribe in Arizona were able to work together with local
ranchers to protect springs in the Cibecue Creek watershed 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.
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.
Evaluate community participation
The tribe will need to evaluate the role of the non-tribal community in the WAM
process (Box 5). Issues such as multiple jurisdictions within the watershed, multiple
landowners, and distrust among tribal and non-tribal community members and state and
federal agencies will present obstacles to full community participation. Understanding the
relationships among community members will play a critical role in structuring the WAM
process and determining who to include at various stages.
Broad representation will create a more powerful analysis that can effectively improve
community resources. Cooperators such as local, state, and federal agencies may be able
to provide staff and other valuable resources to strengthen the assessment. 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.
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Box 5. Citizen involvement, Flagstaff, Arizona
The City of Flagstaff needed to update its growth management guide. The city brought together the
USDA Forest Service (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, and floodplain 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)
Ideally, the Scoping participants will consist of tribal members and tribal natural
resources staff together with community representatives. Potential scoping participants
include the following (EPA 1997):
Offices of tribal governments
- Natural resources department
- Cultural resources department
- Community education department
Tribal members
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, and federal governments
- Local watershed organizations and conservation districts
-EPA
-NRCS
-USFS
- State and county departments of environmental protection
Scofin
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Organizations that use the watershed or are concerned with watershed or land use
issues
- Water recreation organizations
- Public health organizations
- Community economic development organizations
- Environmental groups
Step 2. Plan and conduct scoping meeting
The objectives of the Scoping meeting are to 1) provide an open forum for community
input, 2) prioritize watershed issues, and 3) determine WAM project goals. The focus of
the Scoping meeting should be sharing information and generating ideas to help create a
more neutral and cooperative atmosphere.
Prepare for Scoping meeting
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.
The following materials are helpful for Scoping 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 6).
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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.
Photographs. Standard and aerial photographs are often useful for illustrating various
watershed conditions or issues.
Box 6. 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 (Omernick 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/ceisweb1/ceishome/atlas/
bioindicators/ecoregions_of_the_united_states.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.
Organize meeting logistics
Depending on the scale and amount of community participation for the Scoping
meeting, the following preparations may need to be made:
10
Scoping
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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 tribal or other 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. A facilitator may be useful to help mediate discussions and
stay 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 the Scoping participants may be used to help
record this information.
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 Scoping meeting
Prioritize key watershed issues
One crucial output from Scoping is identification of key watershed issues concerning
human activities that may be impacting a community resource. The watershed issues
should outline the perceived connections between human land use, the response in
watershed conditions, and community resource impacts.
11
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Visually displaying the location of community resources and areas of concern can be a
useful organizational and learning tool for Scoping 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.
The tribal community may have already determined their key watershed issues (Step 1)
and at this stage can share them with the larger watershed community. Community
participants may identify new issues or emphasize different aspects of issues that will
require changing or broadening WAM project goals.
Establish WAM project goals
A number of topics need to be considered as the Scoping group starts to establish WAM
project goals. The tribe may want to share their project goals (Step 1) and solicit input
from the community on the objectives and approach of the proposed WAM project.
The tribe will have likely discussed the following issues internally but may need to
review them with the Scoping participants:
Group organization.
Scope of assessment.
Assessment level of detail.
Staff and other available resources.
Assessment team composition.
Information management.
Funding and other support.
Schedule.
Tribal project goals may be expanded or refined based on community responses.
Discovering funding or partnership opportunities may expand the scope of the
Watershed Assessment and allow the WAM project to meet broad community goals.
Once the WAM project goals are finalized, record them on Form SC2 (Figure 2).
Scoping
12
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Figure 2. Sample Form SC2. WAM project goals
Assessment
Project Goal Level
1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
11.
Document tribal cultural sites in the watershed.
Document historical and current distribution of fish.
Create digital maps showing stream classes, irrigation diversions,
dams, and water quality impairment.
Create an inventory of culturally significant plants used by the tribe.
Summarize current knowledge of watershed conditions and
available documentation.
Increase communication between the tribe and other community
members and education opportunities.
Evaluate the effectiveness of stream restoration projects over the
past five years.
Evaluate the impacts of forestry, agriculture, and urbanization on
fish habitat conditions.
Examine the potential causes of increases in the frequency and
size of floods.
Create a watershed management plan with multiple options for
changing land use practices and restoration projects.
Create a TMDL plan for streams that do not attain the water
temperature standard.
Level 1
Level 1
Level 1
Level 1
Level 1
Level 1
Level 1
Level 2
Level 2
Level 2
Level 2
Step 3. Refine final scope of watershed assessment
Scoping participants should review the key watershed issues and project goals with the
assessment team or technical advisors. This discussion will help to ensure that the
Watershed Assessment will meet the proposed project goals. The technical advisors
should comment on the following questions:
Which 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?
Where are Level 2 methods necessary to meet project goals?
Are there sufficient resources available to conduct the assessment?
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What is a realistic schedule to complete the Watershed Assessment?
What issues will require long-term data collection?
A useful tool for outlining the watershed issues and assessment needs is the creation
of conceptual models. Figure 3 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 3 lists some
common watershed issues and the modules and associated critical questions that address
each issue.
Technical advisors may want to discuss hypotheses about watershed processes and
resource impacts. The process of generating hypotheses is discussed in more detail in the
Watershed Assessment section. These hypotheses may also help in determining the scope
and level of assessment necessary to meet project goals. Hypotheses related to issues
identified in Figure 3 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. Any changes in the project
goals should be reflected on Form SC2.
Scoping
14
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Figure 3. 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
BM 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),
KB 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 streamside vegetation can increase bank erosion,
DELIVERED
TO STREAM
15
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Table 3. Examples of watershed issues and applicable modules and critical questions
Watershed Issues
Floods
Drinking water
Floodplain/riparian
conditions
Algae blooms/
eutrophication
Water temperature
Loss of medicinal/
food plants
Modules
Hydrology
Channel
Historical Conditions
Water Quality
Hydrology
Community Resources
Vegetation
Community Resources
Aquatic Life
Hydrology
Channel
Water Quality
Aquatic Life
Water Quality
Aquatic Life
Vegetation
Community Resources
Vegetation
Critical Questions*
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?
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?
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?
A3: 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?
WQ7: What causes excessive algae growth or eutrophication?
A5: What connections can be made between past and present
human activities and current habitat conditions?
WQ2: What water quality parameters do not meet the standard
and for what time period?
A3: 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?
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: A = Aquatic Life
C = Channel
CR = Community Resources
E = Erosion
H = Hydrology
HC = Historical Conditions
V = Vegetation
WQ = Water Quality
Scoping
16
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Table 3. (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 overtime?
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
overtime?
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
17
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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.
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 and T. 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.
Scoping
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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, DC.
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.
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Form SC1. List of watershed issues
Watershed Issue
Affected Resources
Potential Causes
Scoping
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Form SC2. WAM project goals
Project Goal
Assessment
Level
Scoping
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Scoping
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Step 2: Watershed
Assessment
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Introduction
The Watershed Assessment step relies on an
interdisciplinary scientific approach to gather
information about ecosystem processes, resource
conditions, and historical changes due to the
cumulative effects of management practices. 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.
Box 1. Technical modules
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 Process
Step Chart
Procedure
Conduct assessment using
technical modules
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.
Conduct assessment team orientation
Conduct pre-Synthesis meeting
Watershed
Assessment
page
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Step 1. 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 used in Scoping) 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 the Watershed Assessment report. Table 1
provides a list of materials that are typically necessary for a Level 1 assessment.
Table 1. 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
Watershed
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 (Box 2).
Identify sources and availability of watershed data, aerial photos, maps, and
environmental reports.
Assign responsibilities for data collection and analysis (Box 3).
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.
Box 2. 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 streambed.
Watershed
Assessment
-------
Box 3. 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
Issues such as financial resources
and assessment team participation
will typically be addressed during
the Scoping process, but as the
assessment objectives are clarified,
a reevaluation with Scoping
participants may be useful.
Step 2. 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
third section 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.
Step 3. 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.
Watershed
Assessment
-------
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 module reports.
Watershed
Assessment
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Watershed
Assessment
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Step 3: Synthesis
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Introduction
The Synthesis step of the WAM process provides an opportunity for interaction among
the module analysts to provide a more comprehensive picture of the watershed. These
discussions often lead to new insights about important watershed processes and the
status of community resources.
Synthesis Process
Step Chart
Procedure
Identify connections between land use
practices and resource impairment
The objectives of the Synthesis step are as follows:
To share information generated from each
technical module.
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 analysis,
management practices, restoration plans, and
monitoring plans).
Step 1. Prepare for the Synthesis process
The Synthesis process is organized and facilitated by
the assessment team leader. The module analysts
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
Summarize watershed issues
Produce Watershed Assessment report
Synthesis
-------
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 not only important to maintain the focus of the
participants, but it also allows 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 modules along with appropriate maps and forms. The
checklist provided in Box 1 summarizes the important products from each 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 prepared to
document that all necessary work has been completed and to help focus on information
needs of or 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.
The first day of Synthesis meetings is typically devoted to presentations of information
gathered by the assessment team. Presentations should be tailored to the knowledge
and experience of 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.
Synthesis
-------
Box 1. A checklist of module products needed for Synthesis
Module
Products
Community Resources
Aquatic Life
Water Quality
Historical Conditions
Hydrology
Channel
Erosion
Vegetation
n Map CR1. Community resources
D Form CR1. Categorization of community resources
D Form CR2. Trends in community resource conditions
n Map A1. Aquatic species distribution
D Map A2. Aquatic habitat distribution
D Map A3. Aquatic habitat conditions
n Form A1. Summary of hypotheses
D Map WQ1. Water quality impairments
D Form WQ1. Summary of water quality conditions
D Map HC1. Historical sites
D Form HC1. Historical timeline
D Form HC2. Trends in watershed resource conditions
O Map H1. Water control structures
n Form H1. General watershed characteristics
[] Form H2. Summary of hydrologic issues by sub-basin
D Map C1. Channel segments
D Map C2. Geomorphic channel types
D Form C1. Historical channel changes
D Form C2. Geomorphic channel type characteristics
D Map E1. Land types
D Form E1. Summary of erosion observations
D Form E2. Summary of land type characteristics
n Map V1. Upland vegetation
D Map V2. Riparian/wetland vegetation
D Map V3. Land use practices that affect vegetation
D Form V1. Vegetation category summary
Synthesis
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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?
Synthesis
-------
Box 3. Assessment team presentations
Each module analyst should present the following information:
Module objectives and critical questions.
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.
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.
Box 4. An example of identifying connections between
an impaired resource and land-use practices
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
RGBs. 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 oper-
ations 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.
Synthesis
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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.
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 sensititivities
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
Box 5. Organizing watershed issue, example
from the Penobscot River basin, Maine
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:
The Penobscot River Basin has a number of benefi-
cial 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
organized according to the hazardous inputs:
1) RGBs 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
Synthesis
-------
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.
Box 6. Information to include in Form S1. Summary of watershed issues
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.
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
Watershed Issue: The community resource, hazardous input, or land use practice that
is the focus of the issue should be clearly identified.
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.
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.
Recommendations'. The quality of data available for the Watershed Assessment,
the assessment scale or level of detail, and the confidence in conclusions drawn
Synthesis
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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.
Synthesis
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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.
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.
Jiistification: 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).
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 are required
to recommend management changes or
restoration plans.
Box 10. Confidence summaries
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.
Synthesis
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Step 5. Produce Watershed Assessment report
IV.
The assessment team leader will be 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.
Box 11. Example outline for a Watershed Assessment
report
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
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.
10
Synthesis
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Form S1. Summary of watershed issues
Watershed Issue:
Location:
Situation Summary:
Recommendations:
Justification:
Synthesis
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12
Synthesis
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Step 4: Management
Solutions
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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 will 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., tribal 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 Scoping, Watershed Assessment, and Synthesis
steps, the WAM approach can provide a strong link between community values, scientific
information, and the development of practical and effective management solutions.
Solutions
page
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Reports and forms from the Watershed Assessment and Synthesis processes are 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
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Step 1. Assemble management team
The management team will be responsible for setting management objectives and
developing a set of options for each objective. Deciding who will participate on
the management team depends upon the number of people involved in the WAM
process. In most cases, representatives from tribes and the community will make up the
majority of the 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. If a small number of people are involved in the WAM process, it
may be possible to include all participants in the management team.
A combination of people with land management, technical, and policy backgrounds
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 should be a part of the management team to provide background
information and help resolve technical questions. Land managers, policy-level people,
and other cooperators from Scoping can be integral for developing educational programs
or evaluating regulatory changes.
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
'it page
Solutions 3
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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)
Land management options
Table 1 provides examples of management objectives and options to minimize aquatic
impacts 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:
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Figure 1. Sample Form M1. Summary of management options
Issue
Erosion from gravel
roads
Untreated
wastewater delivery
to the Massassaqua
River
Decline in population
of and access to
medicinal herbs
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 agreements with
private landowners to gain
access to medicinal plant
sites.
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. $1,000
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.
Agriculture
EPA (1984) describes the factors and available research relevant to selecting
appropriate pesticide BMPs.
The National Agricultural Library (http://warp.nal.usda.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.
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page
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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 SMAfrom 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
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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.).
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).
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Solutions 7
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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, reestablishing riffles, and stabilizing stream
banks, but will 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).
Riparian Corridors
Stream Corridor Restoration: Principles, Processes and Practices (Federal Interagency
Stream Restoration Working Group 1998).
A Citizen's 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).
page Management
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8 Solutions
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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
Step 4. Create watershed management plan
The management options detailed in Form Ml will generally require review and prioriti-
zation by a group of community members larger than the management team alone. This
group will need to evaluate management options to ensure that they are feasible and
can be implemented. The management solutions approved will be incorporated into
the final watershed management plan (Box 3). A schedule for the implementation and
completion of management actions is an important part of the watersed management
plan. Options should be prioritized for implementation as financial resources or
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Box 3. Key elements of a watershed management plan
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
Box 4. Cooperation and incentives in a tribal context
more data become
available. Prioriti-
zation will have to
balance the effec-
tiveness of various
measures with the
cost of implemen-
tation.
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 understand-
ing of ecosystems may lead to uncertainties
about the results of the assessment. Com-
munity members may also disagree about the
risk to important resources posed by manage-
ment practices. Some may argue for the least
costly methods, others for the most effective
methods, regardless of cost. It will be impor-
tant to consider incentives for participation
and voluntary, rather than regulatory, imple-
mentation of BMPs (Box 4). Table 3 sum-
marizes potential incentives to consider in a
watershed management plan.
Most discussion of management on tribal lands will involve per-
sonal communication with a land manager, private landowner, or
tribal government representative. Cooperative projects, cost-
share programs, and technical assistance will probably be the
most commonly used incentives. Community meetings and dis-
cussions with the tribal government (e.g., the Tribal Council) will
generally be more productive than will regulatory mechanisms.
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 live-
stock 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.
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,
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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.
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).
Solutions
page
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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.
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.
page
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Solutions
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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 841-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.
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. EPA841-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.
'it page
Solutions 13
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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.
page
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Solutions
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Form M1. Summary of management options
Issue
Management Objective
Management Solutions
Cost Estimate
Rationale
page
Solutions
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Step 5: Adaptive
Management
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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
Adjust watershed
management plan
Adaptive
Management
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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
personnel who can help identify scientific
issues and evaluate monitoring data.
Box 1. Key elements of the adaptive management plan
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 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
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)
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
page
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
resource of concern, for example, water quality, water quantity, and aquatic life.
Consideration should be 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.
Adaptive
Management
-------
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:
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).
page Adaptive
4 Management
-------
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).
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 reevaluation
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 discussed by policy representatives.
Adaptive
Management
-------
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
Management
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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 841-B-97-011, Washington, D.C.
Adaptive
Management
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Adaptive
Management
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Community Resources
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Background and Objectives
"For communities to grow, they must protect the underlying
natural systems on which they are built. "
EPA (1997a)
Tribal and non-tribal communities often exist within the same watershed boundaries.
Although they possess different cultural heritages and often different relationships to
the land, both types of communities
are concerned about the natural
environment in which they live. It is
the goal of this module to identify the
natural resources valued by both tribal
and non-tribal communities in order
to gain a better understanding of which resources will require protection.
The Level 1 Community Resources assessment provides a structure for all communities
to identify and evaluate their valued natural resources in the watershed. The assessment,
however, can be divided to examine tribal and non-tribal community resources separately.
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.
The wishes of the individual tribes regarding the treatment of information about their
cultural resources are paramount and to be respected. In many cases tribes will have severe
reservations or be opposed to revealing specific information regarding traditional uses,
ceremonies, and practices. This module is designed to be flexible and may be modified as
necessary to respect the needs of all communities.
Community
Resources
page
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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 seasonally 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 tribal historian or
anthropologist
Community use analysis
Economic analysis
Detailed interviews
Field work
Community use analysis
* Work with tribal historian or
anthropologist
Detailed interviews
Field work
Detailed interviews
Field work
Community use analysis
page
Community
Resources
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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 tribal elders and other 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 an animal
species that has spiritual value to the tribe or cabins from the early 1800s that document
history of pioneer life in the watershed. Tribal elders may be especially helpful in
identifying uses of 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).
Community
Resources
page
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Box 1. Community resource categories
Spiritual: resources that are important to a religious belief system
Ceremonial: resources used in tribal ceremonies
Lodging: materials used in the construction of living or meeting houses
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
EPA (1997b)
Figure 1. Sample Form CR1. Categorization of community resources
Resource
Rocky Ford
Strawberries
Shumae
Catfish
Squirrels
Hickory
Oak
Off Road
Vehicle trails
Copper
Beaver
Elk
Mushrooms
Site
1
2
3
4
5
6
7
8
9
10
11
12
Spiritual
Ceremonial
Lodging
Natural
Beauty
Recreation
Historical
Subsistence
Economic
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 tribal resources in a broad area or with coded symbols can maintain the security
of important sites.
page
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
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Figure 2. Sample Map CR1. Community resources
Step 3. Identify seasonality of resource use
Natural community resources 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
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 elders 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.
page
Community
Resources
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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
Quileute Annual Cycle
(approx. dates) Sol Due Watershed Activities
January
March
April
May
June
Shaffer et al. (1995)
Hunting small mammals:
land otter and beaver
Steelhead fishing
Root digging: ferns
Skunk cabbage
Camas
Salmon 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
Category
Air Quality
Native
Vegetation
Wetlands
Trout
Trend
Increased smog
during weekends
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 traffic
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
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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
page
8
Community
Resources
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Box 4. Quinault cultural story excerpt
The major residential community of the watershed is the fishing village of Taholah situated at
the mouth of the Quinault River. A 1780 census from the Native American Almanac reports
a population of 1,500 for the Quinault tribe. Lewis and Clark visited the Columbia region in
1805 - they list the Qui ni ilts (Quinault) at 1,000 with 60 lodges (Storm et al. 1990). In 1870
the Quinault Agency reported 130 Quinaults, by 1888 the population had dropped to 95. It
is very difficult to estimate the size of the Quinault tribe for the period before the catastrophic
events and epidemics in the later portion of the 1700s and succeeding outbreaks in the mid-
1800s.... The diseases virtually wiped out the old way of life by decimating the Quinault proper
from around 1,000 in the 1700s to about 100 in 1885.
The indigenous populations of the Quinault watershed traditionally harvested a wide variety
of fish, shellfish, waterfowl, plants, trees and marine animals for subsistence and cultural
purposes. In addition, the Quinaults maintained an extensive regional trading system.
They were semi-nomadic, but settled along the riverbanks to harvest and process the
seasonal runs of salmon. Inland trails connected many of the villages and tribes throughout
the Olympic Peninsula. Although harvesting methods have changed and the tribe has a
somewhat diversified economy today, natural resources continue to provide food, security,
cultural identity, and significant sources of income for tribal members. Resources, including
land, were plentiful and to be shared by all.
The Quinault people are principally riverine oriented; hence the development of the cedar, and
occasionally spruce, dug-out canoe for transportation. A special adaptation for the Quinault
River was the shovel-nosed canoe. The double bow allowed the canoe to slide over logjams
much easier than the regular models. They also constructed large ocean-going canoes for
travel along the Pacific Ocean coastline. The modes of transportation have changed; skiffs,
jet sleds, large ocean-going boats and modified canoes are now used, but the waterways
continue to provide important thoroughfares.
Quinault Indian Nation (1999)
Community
Resources
page
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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 cultural 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
' Communities (EPA 1997a).
Cultural Importance of Community Resources
Describing the 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 tribal elders 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. One way to summarize traditional uses of plants is
in an ethnobotany chart (Box 5).
Provide additional detail on the spiritual or historical significance of locations in
the watershed.
In addition to identifying the importance of specific resources and locations,
describing tribal songs, art, and stories and documenting migratory patterns and
movement to reservations will improve the community's understanding of the tribe's
cultural heritage.
10
Community
Resources
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Box 5. Sample ethnobotany chart
Scientific Name
Pyrus fusca
Rhamnus purshiana
Ribes divaricatum
Ribes laxiflorum
Rosa nutkana
Rubus laciniatus
Rubus leucodermis
Rubus parviflorus
Rubus spectabilis
Rubus ursinus
Rumex obtusifolius
Sagittaria latifolia
Salicornia spp.
Salix hookeriana
Sambucus caerulla
Sambucus racemosa
Satureja douglasii
Scirpus acutus
Shepherdia canadensis
Sphagnum spp.
Spiraea menziesii
Stachys mexicana
Quinault Indian Nation
Common Name
western crabapple
cascara
common gooseberry
trailing blackcurrant
Nootka rose or rose
hips
evergreen blackberry
black cap
thimbleberry
salmonberry
trailing blackberry
bitter dock
wapato, Indian potato,
or arrow leaf
glasswort
Hooker willow
blue elderberry
red elderberry
Indian tea
hardstem bulrush
soapberry
sphagnum moss
Menzies' spirea
hedge nettle
(1999)
Quinault Name
qwe'tsunixlax
kwi'tsanitl
xwixwi'nil
klw'e'mwus, le'imk's
p'ookwa
whle'?nit
swaha
xe'e'nis, hi'?inis
k'wklaxnix, k'wela
wha's
-
metchi'?ilsmani
chi'nmuut
-
laleah-kilech
k' we' lap
k'lolmanix, kalu'm
slegwelmi'sh
-
-
tso'otcilminix
tsapa'snixl
qwadjodkolum
Common Uses
berries for food and medicine eyewash, arthritis
and internal disorders
purgative and laxative
food source cakes
food berries eaten immediately or dried
food supplement for soups and stews and medicine
for sore eyes
food eaten immediately or dried
berries eaten immediately or dried
food and elderberry storage (leaves)
berries for food, medicine for labor pains, cleaning
wounds, and associated with blueback runs
food berries
menstrual medicine
food the tubers are similar to the potato
food supplement for stew, soup, or salads (salt
content)
string or twine for fish lures and plugs and harpoon
line
elk whistle and emetic tea
food, food preservative, and emetic tea
medicinal cold remedy
material for packsacks and basket construction
the berry whipped into a foam is an excellent des-
sert supplement
cleaning sponge
string to roast clams
food the nectar of the plant
Community
Resources
page
11
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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.
page Community
12 Resources
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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)
Community
Resources
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13
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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
page
14
Community
Resources
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References
Quinault Indian Nation. 1999. Quinault watershed analysis: cultural module (DRAFT).
Quinault Indian Nation, Taholah, Washington.
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.
Community
Resources
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15
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Form CR1. Categorization of community resources
Resource
Site*
Spiritual
Ceremonial
Lodging
Natural
Beauty
Recreation
Historical
Subsistence
Economic
Other
* Identify locations on Map CR1. Community resources
page
16
Community
Resources
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Form CR2. Trends in community resource conditions
Resource
Trend
Sources of Impairment
Related Modules
Community
Resources
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Community
Resources
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Aquatic Life
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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.
Aquatic Life
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Aquatic Life Module Reference Table
Critical Questions
Information
Requirements
Level 1
Methods/Tools*
Level 2
Methods/Tools*
A1:
What are the valued
aquatic species that are
present in the watershed?
A2:
What are the distribution,
relative abundance,
population status, and
population trends of the
aquatic species?
A3:
What are the
requirements of various
life history stages of the
aquatic species?
A4:
What are the habitat
conditions for the aquatic
species?
A5:
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
Aquatic Life
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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
FormAl. Summary of hypotheses
MapAl. Aquatic species distribution
Map A2. Aquatic habitat distribution
Map A3. Aquatic habitat conditions
Aquatic Life report
Collect aquatic species and
habitat information
Summarize aquatic species
population information
Summarize ecological needs
of aquatic species
Develop habitat evaluation criteri
Evaluate current habitat conditions
Reevaluate hypotheses
Aquatic Life
page
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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 Al, 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
4 Aquatic Life
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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.
Aquatic Life
Channel
Hydrology
Vegetation
Water Quality
Historical
Conditii
page
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Channel
Vegetation
Water Quality
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 Al.
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:
page
Floodplain characteristics.
Riparian characteristics.
Streambank characteristics.
Stream channel, lake, and wetland characteristics.
Streambed substrates.
In-stream wood debris.
Habitat quantity.
Water quantity and quality.
Aquatic Life
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Figure 1. Sample Form A1. 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.
Aquatic Life
page
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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.
Box 5. Development of human disturbance criteria
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.
Box 3. Sources of habitat suitability models
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 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 potential to change habitat
conditions or alter population status.
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).
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)
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).
page
8
Aquatic Life
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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 > 8 mg/L
Adult, juvenile Turbidity (suspended < 25 ppm
solids)
Adult, juvenile Percentage pool habitat > 60%
Adult, juvenile Percentage cover in 40 - 60%
pools
Adult, juvenile Summer water 24 - 30°C
temperature
Incubation Water temperature 13-26°C
Fry Water temperature 27-30°C
All Salinity < 1.66 ppt
4 - 8 mg/L
25-100 ppm
< 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).
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
Aquatic Life
page
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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.
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
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
page
10
Aquatic Life
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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.
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.
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.
Step 8. Produce Aquatic Life report
Produce maps
At least two and possibly three maps will be generated from the assessment. Map Al will
present species distribution. An option is to also present historical distribution if it will
contribute to the Synthesis discussions.
Maps A2 and A3 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
Channel
Hydrology
Vegetation
Water Quality
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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, 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.
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
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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 maps to
assist in the development of hypotheses regarding channel and habitat responses to inputs
such as sediment, water, and vegetation.
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 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.
Channel
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Aquatic Life 13
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Box 7. Sample summaries of confidence in the assessment
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.
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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 of fish 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.
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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).
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16 Aquatic Life
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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 itselfrather than an
indicator such as habitat conditions or water qualityis under study. Also, regional values
for fish and macroinvertebrate 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
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Aquatic Life 17
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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.
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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. Horner, 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.
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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.
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., F. H. Everest, and T. 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.
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Form A1. Summary of hypotheses
Species
Sub-basin
Description
Hypothesis
Source (include
watershed expert
as appropriate)
Aquatic Life
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Aquatic Life
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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
Water Quality
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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
,1
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
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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
Water Quality
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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
-------
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
NPDESdata
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
Water Quality
-------
Background and Objectives
Step Chart
Data Requirements and Sources
Identify water quality standards and criteria
Identify indicators of impairment
Analyze water quality data
Data requirements
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 potential pollution sources
Produce Water Quality report
Water Quality
-------
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
Water Quality
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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
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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?
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8
Water Quality
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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 of fish 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
-------
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
Backgroun
monitoring
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H
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and f isherii
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Chapman (1996)
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
k.
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Water Quality
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
page
12 Water Quality
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decreases. pH affects the reaction and equilibrium relationships of many chemicals. Many
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.
Nutrientsphosphorus,
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
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
14 Water Quality
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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 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 of fish, 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
16 Water Quality
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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
e
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-.05
0.02-0.1
1000-2000
Region
Great Plains
20-100
2-3
0.2-.05
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
17
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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
18 Water Quality
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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
T
Compare water quality data
with reference conditions
T
Evaluate indicators of
water quality conditions
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
19
-------
A
Community
Resources
Historical
Conditions
Community
Resources
A
Aquatic Life
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.
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.
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
20
Water Quality
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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
Identify 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
21
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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 of fish 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.
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22 Water Quality
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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
23
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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
24
Water Quality
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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 25
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Loading Tables
A
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
entral business
strict
o -o
1080
1070
7.1
3.0
2.1
4.5
15
2.8
ther commercial
O
840
1020
3.0
3.3
n.a.
0.67
15
2.7
are given where
to
s
CO
£
>5
"5>
c
CO
£
o
n
a.
2
.= (/) S 0
56
63
2.0-7.1
3.5- 12
0.33-1.1
0.45
2.2- 15
0.9-4.0
available;
17
28
0.1
0.22
0.03
0.33
1.1 -5.6
0.2-1.5
otherwise
440
330
0.7
0.33
0.33
3.8
3.4-4.5
1.3-1.6
ranges are
450
n
0.005
0.03
0.01
7
1
0.1
reported
a.
-0.006
-0.08
-0.06
9
7
-3.0
CD
CO
0.
340
n.a.
0.003-0.015
0.02-0.17
0.02-0.04
0.33
0.67
0.07-3.0
to
£
o
L
L.
85
n
0.01
0.01
0.02
0
2
0.02
a.
-0.03
-0.03
-0.03
56
.9
-0.45
c
V
a.
O
7
2.0
n.a.
n.a.
n.a.
0.33
1.7
0.06
Adapted from Homer et al, (1986)
page
26
Water Quality
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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.
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.
Hydrology
Vegetation
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,
Water Quality
27
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vegetation of a given height is less effective in shading wider channels. Wider and
Channel
Erosion 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)
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
28 Water Quality
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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.
Figure 4. A simplified pathway of DO
Deoxygenation
due to BOD
Oxygen
generation by
photosynthesis
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):
Cs =-139.34411 +
1.575701 E5
T
6.652308 E7
T2
1.2438 E10
8.621949 Ell
T3
Where: T = temperature in degrees Kelvin (°C + 273.15).
C§= DO saturation (mg/L)
Water Quality
29
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C =
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:
Ka -Kr
x x
exp(-Kr exp(-Ka
U
U
L0 - (cs- c0)exp(-Ka
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
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
n|trobacter
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
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
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
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
33
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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 = Gr
Where: G = growth rate based on nutrient limitation.
Gmax = temperature corrected maximum growth rate.
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
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 microflora, 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 microflora
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
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
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
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
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
1
Y
Y
Y
Y
Y
Y
N
Y
Y
N
Y
Y
N
Y
Y
N
Y
N
Y
-------
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
40
Water Quality
-------
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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
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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.
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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
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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
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Heaney, J. P. 1989. Cost effectiveness and urban storm-water quality criteria. In: L.
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controls. ASCE, New York, New York.
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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 F. 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
42 Water Quality
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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 43
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U.S. Environmental Protection Agency (EPA). 1996b. The volunteer monitor's guide to
quality assurance project plans. EPA, EPA-841-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 and TMDL 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
44
Water Quality
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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 Quality
45
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46
Water Quality
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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
Historical Conditions
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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
page
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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
Historical
Conditions
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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
page
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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
Historical
Conditions
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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
page
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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 Historical
6 Conditions
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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
page
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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
8
Historical
Conditions
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References
Quinault Indian Nation. 1999. Quinault Watershed Analysis. Quinault Indian Nation,
Taholah, Washington.
Sasich, J., P. 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
page
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Form HC1. Historical timeline
Date
Historical Event
10
Historical
Conditions
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Form HC2. Trends in watershed resource conditions
Resource
Trend
Disturbance
Historical
Conditions
page
11
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page
12
Historical
Conditions
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4
Hydrology
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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.
Hydrology
page
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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
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.
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
Data Sources
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
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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
4 Hydrology
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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 H1. 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 5
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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 characteristicssuch as the size of a river system, drainage
shape, topography, type of vegetation or ground cover, and amount of natural water
storageall 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
6 Hydrology
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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
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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
8
Hydrology
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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- Box 1. Regulated watersheds
Uage 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
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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
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10
Hydrology
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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
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11
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page
Aquatic Life
Aquatic Life
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.
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.
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.
12
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
Hydrology
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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?
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13
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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
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14 Hydrology
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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.
Box 6. Hydrologically closed systems
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
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
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.
Erosion
its average annual flow.
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
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15
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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
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16
Hydrology
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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 , , Box 9. Example runoff descriptions
As a general rule, overland now
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
17
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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
Channel
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).
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
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18
Hydrology
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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.
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).
Box 11. Consumptive water use
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.
Water
Quality
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
19
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Figure 5. Hypothetical hydrographs demonstrating
changes between pre-urbanization (dotted curve) and
post-urbanization (solid curve) runoff
01
I
o a>
= Q
03
as
cc
Lag time after
urbanization
Lag time before
urbanization
Time (hours)
Adapted from Leopold (1968)
with urbanization inhibit infiltration, causing
rain to run off more quickly, as shown in
Figures 5 and 6 and described in Box 12.
The screening steps will draw on the information
gathered in the characterization section and offer
guidance for the analyst to determine which
potential land or water use issues warrant further
investigation. For each sub-basin, enter a "Yes" or
"No" under each use category on Form H2. A
"Yes" on Form H2 indicates that a potential for
hydrologic impacts exists for the use in the sub-
basin. A "No" indicates that either the use does
not occur in the sub-basin or that the impact is
projected to be minimal. In addition, the last
column on Form H2 encourages comments on the
rationale behind each screening response.
Box 12. Example of
urbanization impacts
Urbanization causes the
peak flow (highest point on
the curve) to increase and
to occur sooner (the lag
time has decreased), as
shown in Figure 5. The
same concepts are shown
in Figure 6, where two
streams respond differently
to the same rainstorm: one
stream drains a forested
watershed, and the other
drains an urbanized
watershed.
Keep in mind that the work completed in this screening is not definitive.
More detailed technical analyses are necessary to verify the presence of
Figure 6. Atypical annual hydrograph based on mean monthly flow values
v
ra
u
CO
6 8 10
Time (days)
page
20
Hydrology
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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
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.
Stepl. 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
Sub-basin
name
Entire
watershed
Land use categories (% of watershed area)
Rural
Forestry Agriculture Rangeland Urban residential Other
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
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22
Hydrology
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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
issuepeat 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
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23
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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
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
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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 roof tops. 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
25
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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
26 Hydrology
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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.
Hydrology
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27
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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.
Aquatic Life
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. Flow duration curves provide a
graphical representation of the percentage of time that a given level of Streamflow will
be equaled or exceeded in the stream; monthly flow duration curves are generated using
mean daily discharge values. Flow duration curves can be extremely useful in providing
input to the Aquatic Life module.
28
Hydrology
-------
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.
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
page
Hydrology 29
-------
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).
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
page
30 Hydrology
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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.
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
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
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).
Hydrology
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31
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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.
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 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.
page
32
Hydrology
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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.
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
page
Hydrology 33
-------
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)
DRAINMOD/DRAINLOB - 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)
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
34
Hydrology
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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.
Hydrology
page
35
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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.
Watershed Professionals Network. 1999. Oregon watershed assessment of aquatic
resources manual. Draft report prepared for the Governor's Watershed
Enhancement Board, Salem, Oregon.
White, K. A., and R. A. Sloto. 1990. Base-flow frequency characteristics of selected
Pennsylvania streams. U.S. Geological Survey, Water Resources Investigation
Report 90-4160, Reston, Virginia.
Williams, J. R., H. E. Pearson, and J. D. Wilson. 1985. Streamflow statistics and
drainage-basin characteristics for the Puget Sound Region, Washington, volume
II, eastern Puget Sound from Seattle to the Canadian border. U.S. Geological
Survey, Open-File Report 84-144-B, Tacoma, Washington.
Winter, T. C., J. W. Harvey, O. L. Franke, and W. M. Alley. 1999. Ground water
and surface water: a single resource. U.S. Geological Survey, Circular 1139,
Denver, Colorado.
page
40
Hydrology
-------
Form H1. General watershed characteristics
Watershed Name:
Sub-basin information:
Sub-basin
name
Total
watershed
Sub-basin
area (mi2)
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
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
42
Hydrology
-------
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
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
-------
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.
page
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 do 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?
Aerial photos
Topography maps
Geology maps
Anecdotal information
Stream survey data
Annual peak flow data
Climate data
Historical set of aerial
photos
Anecdotal information
Historical set of aerial
photos
Anecdotal information
Historical set of aerial
photos
Sediment source data
Anecdotal information
Historical set of aerial
photos
Riparian vegetation data
Anecdotal information
Streamflow data
Historical set of aerial
photos
Water withdrawal data
Anecdotal information
Hydrology data
Sediment transport data
Streamflow data
Review of maps and aerial photos
Apply existing channel classification
Define channel types
Review of aerial photos
Define channel types
Interviews
Review of aerial photos
Review of aerial photos
Interviews
Review of aerial photos
Interviews
Review of aerial photos
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)
Review of suspended or bedload
transport data
Sediment transport equations
Sediment budget (Erosion)
Channel
page
-------
Channel Module Reference Table (continued)
Critical Questions
Information
Requirements
Level 1
Methods/Tools
Level 2
Methods/Tools
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?
Aerial photos
Historical set of aerial
photos
Anecdotal information
Streamflow data
Historical set of aerial
photos
Anecdotal information
Aerial photos
Topography maps
Geology maps
Review of aerial photos
Interviews
Review of aerial photos
Interviews
Review of maps and aerial photos
Apply existing channel classification
Define channel types
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
-------
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
T
Interpret channel responsiveness
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
-------
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:
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 classifica-
tion and highlight stream reaches that may require further study. Using a topographic map, deter-
mine 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.
12
v
o
E
BJ
10
8
6
2
Longitudinal Profile for Bear Creek, Wyoming
Lower gradient may indicate
sediment deposition and more
meandering or bank erosion
Higher gradient may indicate
different channel form or
stream bed character
River Kilometer
page
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. Channel segments
Toll River Watershed
Response Segments
From WFPB (1997)
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
Buffington 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
-------
Figure 2. Watershed map illustrating application of stream
classification based on stream gradient and morphology
CO
CO
CO
CO
-f -/--
CA
CA
CO = Colluvial
CA = Cascade
SP = Step-Pool
PR = Pool-Riffle
R = Riffle
f = forced by large wood
Watershed Outlet
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.
Montgomery and Buffington (1993)
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
8
Channel
-------
Figure 3a. Stream types: gradient, cross section, plan view
FLOOD-PRONE AREA
BANKFULL STAGE
Figure 3b. Cross-sectional view of stream types
Dominant
Bed
Material
A
B
D
DA
2
BOULUEH
3
COOBLE
4
OPAVEL
5
SANO
t^^v^
r
6
SILT/CLAV
ENTRH.
1.4-2.2
>2.2
N/A
>2.2
>2.2
SIN.
1.1-1.6
>t.2
W/D
>40
<40
SLOPE
.04-.099 .02-.039 <.Q2
<.04
<.C05
<.02
<.02
.02-.039
Rosgen (1994)
Channel
page
-------
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
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
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
ra
±
15
ra
»
0
\
I
ra
±
o
2
ra
Low
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
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.
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 Buffington 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.
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.
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
Erosion
Hydrology
Vegetation
Erosion
Erosion
Hydrology
Vegetation
Aquatic Life
Channel
page
13
-------
Figure 6. Sample Map C2. Geomorphic channel types
QJ North Fork canyon
South Fork canyon
f-| Tributaries to the
Middle North Fork
Steep Tributaries draining
convergent topography
North Fork braided chutes
From WFPB (1997)
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
14
Channel
-------
Figure 7. Sample Form C2. Geomorphic channel type characteristics
Channel
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
Channel
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
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).
page
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
page
Channel 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
18
Channel
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Figure 8. Indicators for determining bankfull width
Floodplain
Bank Shape
Indicators:
1. Floodplain
2. Bank Morphology
and Composition
3. Vegetation
Soil ' ; -
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:
\I2\
V=(l/n)(R2/3)(S
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
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
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 (D50) and the diameter at two standard deviations from the mean (D16 and Dg4).
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- Hydrology
specific estimates may be necessary for stream power and sediment transport analysis.
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:
page
Channel 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:
Q = pgQs
Where: Q = 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:
i = 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:
page
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
(Bricel960).
Several reviews of fluvial classification systems exist to help evaluate various approaches
(Goodwin 1999; Thorne 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.
page
Channel 23
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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
Hydrology ^
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.
page
24 Channel
-------
Table 3. Examples of channel issues and selected techniques for evaluating
changes in channel conditions
Example questions
How much introduced sediment will be
transported out of the watershed?
What proportion of introduced sediment will
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?
Adapted from Reid and Dunne (1996)
Aerial Field Flow Substrate Transport
photos surveys equations analysis equations
V V V V V
^
-------
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:
page
26 Channel
-------
P < We / 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)/rp for sands and gravels
u* = (T/p)a5
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
page
Channel 27
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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/sediinent.
Figure 9. The relationship between suspended sediment and discharge data,
Newaukum River, Washington, 1964-1965
8000
7000
> 6000
CO
~ 5000
g 4000
(f)
"8
-D 3000
v
a.
CO
2000
1000
y = 3E-05X
R2 = 0.9464
1000 2000 3000 4000
Water Discharge (cfs)
5000
6000
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
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.
page
Channel 29
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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
30
Channel
-------
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Aldridge, B. N., and J. M. Garrett. 1973. Roughness coefficients for stream channels in
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Barnes, H. H., Jr. 1967. Roughness characteristics of natural channels. U.S. Geological
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Benson, M. A., andT. Dalrymple. 1967. General field and office procedures for indirect
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Chow, V. T. 1959. Open-channel hydraulics. McGraw Hill, New York, New York.
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transport and channel morphology: A guide for planners. State of California
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Cowan, W. L. 1956. Estimating hydraulic roughness coefficients. Agricultural
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Dendy, F. E., and W. A. Champion. 1978. Sediment deposition in U.S. reservoirs.
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Dietrich, W. E., T. Dunne, N. F. Humphrey, and L. M. Reid. 1982. Construction of
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Downs, P. W. 1995. River channel classification for channel management purposes. , Pp.
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Gregory, K. J., and D. E. Walling. 1973. Drainage basin form and process. Wiley, New
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Harrelson, C. C., C. L. Rawlins, and J. P. Ptoyondy. 1994. Stream channel reference sites:
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Laird, J. R., and M. D. Harvey. 1986. Complex-response of a chaparral drainage basin
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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.
page
Channel 35
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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.
page
36
Channel
-------
Form C1. Historical channel changes
Channel
segment(s)
Historical changes
Other observations
page
Channel
37
-------
Form C2. Geomorphic channel type characteristics
Channel
type
Description
Channel
segments
Potential responsiveness rating
Sediment
Runoff
Vegetation
Evidence supporting rating
page
38
Channel
-------
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
Erosion
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-------
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
page
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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
USES 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
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
page
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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 E1. Land types
Erosion report
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
Procedure
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
Erosion
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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, tribal members and other 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.
Channel
Vegetation
Water Quality
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
Erosion
page
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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
f
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
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. Penobscot 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
page
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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
Moraine
Fluvial Lands
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
Erosion
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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 Haskins 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
page
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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
10
Erosion
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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
page
11
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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
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
page
13
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Landslides
Landslide evaluation on a watershed scale typically involves aerial photo analysis and
creation of a landslide inventory. Typically, 1:25,000-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
14
Erosion
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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.
page
Erosion 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)
16
Erosion
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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
page
Erosion 17
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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 (WFPB 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.
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18 Erosion
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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.
page
Erosion 19
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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
page
20 Erosion
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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)
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Erosion 21
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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
Channel
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
22
Erosion
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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.
Haskins, 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
page
23
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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
Landforms8(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
24 Erosion
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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., andT. Dunne. 1984. Sediment production from forest road surfaces. Water
Resources Research 20(11):1753-1761.
Reid, L. M., and T. Dunne. 1996. Rapid evaluation of sediment budgets. Catena Verlag,
Reiskirchen, Germany.
Reinig, L., R. L. Beveridge, J. P. Potyondy, and F. 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.
page
Erosion 25
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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.
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26
Erosion
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Form E1. Summary of erosion observations
Number Erosion Feature
Location
Observations
page
Erosion
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
28
Erosion
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Vegetation
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-------
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 inuenced 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
team. In addition, the analyst may gain a preliminary sense of which functions the
Vegetation
page
1
-------
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
Vegetation
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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 V 1
Floodplain surveys
Local "sensitive" or "critical
areas" inventories
* Same as for V 1
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
Vegetation
page
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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
Vegetation
-------
Level 1 Assessment
Step Chart
Data Requirements
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.,
"WaterTypes" 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
Collect background vegetation Information
Upland
Riparian
Wetland
Vegetation
page
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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
Although the "Data Requirements" section lists items that may be useful, the critical
elements are as follows:
Box 2. A practical note
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
Vegetation
-------
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).
Vegetation
page
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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 Vege-
tation module is the simplest system that captures important functional differences among vegeta-
tion categories. The chosen system should also be mapable at the scale being used for other prod-
ucts. 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.
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Vegetation
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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.
Vegetation
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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.
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10
Vegetation
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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.
Vegetation
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11
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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
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12
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
Vegetation
-------
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
Quality 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.
e. 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.
f. 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
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.)
Vegetation
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13
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Figures. Sample Map V3. Land use practices that affect vegetation
Dike
maintenance
Grazing
Step 5. Produce Vegetation report
page
14
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.
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.
Vegetation
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15
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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.
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Vegetation
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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
Vegetation
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17
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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).
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18 Vegetation
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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
me
Vegetation 19
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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
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20
Vegetation
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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
particular land use of interest:
- All land use types - tribal or county planning/zoning agencies.
- Forestry - forestry agencies or companies.
- Agriculture/grazing - NRCS.
Resources r
_
Vegetation 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.
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Vegetation
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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.
Vegetation
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23
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Van Sickle, J., 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.
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Form V1. Vegetation category summary
Vegetation category:
Primary species:
Unique or culturally valuable plant species present:
Land use impacts:
Functions:
Field sites visited:
Vegetation
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26
tation
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Glossary
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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.
Glossary
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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.
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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.
Glossary
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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 1st- and 2nd-order streams
Hillslope process:
(see Geomorphic process)
Hydro geology:
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.
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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.
Landform:
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.
Glossary
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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.
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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.
Glossary
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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.
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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.
Glossary
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