United States
Environmental Protection
Agency
Office of Water
Washington D.C.
EPA841-B-92-001
July 1392
EPA A Quick Reference Guide
Developing Nonpoint Source Load
Allocations for TMDLs
Printed on Recycled Paper
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A QUICK REFERENCE GUIDE
Developing IMonpoint Source Load Allocations
for TMDLs
Prepared by
Tetra Tech, Inc.
Fairfax, VA
Prepared for the U.S. Environmental Protection Agency
Office of Wetlands, Oceans, and Watersheds
Assessment and Watershed Protection Division
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Table of Contents
1. Introduction and Purpose 1
2. The TMDL Process and Nonpoint Sources 1
3. Prioritization and Targeting 3
4. Tools to Assess Water Quality and Estimate Load Allocations 4
a. Identifying Impaired Water Bodies 5
• Survey of Existing Information 5
• Analysis of Water Quality Information 8
• The Role of Water Quality Monitoring 10
b. Analyzing Pollution Sources 12
• Watershed Characterization 13
• Watershed Simulation Models 16
• Receiving Water Quality Models 18
5. Best Management Practices 20
a. Agriculture 20
b. Forestry 21
c. Urban Areas 21
6. Follow-up Monitoring 22
7. Contacts and References 23
This synopsis was developed in response to the concerns and issues raised at the Section
303(d) Coordinators Conference in February 1992.
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1. INTRODUCTION AND PURPOSE
This synopsis of existing guidance, technical manuals, and case studies is intended to assist EPA
Regional Coordinators, State managers, and local agencies to develop load allocation estimates
for total maximum daily loads (TMDLs). It is a preliminary guide to the information and tools
that are currently available to assess and characterize nonpoint source problems within the TMDL
framework. It can also help to determine the data and tools that are needed to calculate a load
allocation as part of a TMDL, to indicate how sufficient and accurate information can be
obtained, and to facilitate decisions regarding selection and implementation of pollution control
measures. While none of the tools were explicitly developed to derive load allocations, they can
be useful and are appropriate.
This guide provides brief explanations of existing guidance and technical manuals that can best be
used as part of the Clean Water Act (CWA) §303(d) process and in planning on a watershed
level. Documents that are summarized include those that can assist with the establishment of a
monitoring plan to support TMDL project objectives and creation of a data base to facilitate
decision-making, among others.
This document is not intended to be a guidance in the classic sense. No new material or
procedures have been developed. In addition, this document is not intended to replace any future
technical guidance on how to develop and/or implement TMDLs. Until such technical guidance
is available, however, it is important to use the resources that do exist to our best advantage.
The references that are listed and discussed within this document are by no means exhaustive.
There are certainly numerous others that can and will be of use to assist with TMDL
development. EPA Regional Coordinators, State managers, and local agencies are encouraged to
use these other references, as well. Where possible, the name, address, and phone number of
any individual, agency, and organization who can provide support are provided.
2. THE TMDL PROCESS AND NONPOINT SOURCES
Guidance for water quality-based decisions: The TMDL process (EPA, 1991a)
The TMDL process provides water quality managers with an analytical method to address more
complex water pollution problems, such as nonpoint sources, and to adopt a more integrated
approach in their analysis. The Guidance for Water Quality-based Decisions: The TMDL
Process, also known as the TMDL Program Guidance (EPA, 1991a), and the Workshop on the
Water Quality-based Approach for Point Source and Nonpoint Source Controls have set the stage
for the watershed approach and re-emphasized the need for moving beyond the "chemical-by-
chemical and permit-by-permit" point source approach.
To facilitate adoption of the watershed approach, the TMDL Program Guidance (EPA, 1991a)
defined it as five stages or steps. Steps one, two, and three make up the TMDL process.
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1. Identification of water quality-limited waters still requiring TMDLs
2. Priority ranking and targeting
3. TMDL development
4. Implementation of control actions
5. Assessment of water quality-based controls.
The identification of water quality-limited waters and priority ranking and targeting are the focal
steps of the TMDL process. Most of the decisions associated with the development of TMDLs
and control programs are based on the information that is assembled during these two steps. The
identification step was outlined in the TMDL Program Guidance (EPA, 1991a). It requires a
review of applicable water quality standards and the analysis and interpretation of existing water
quality information.
Priority ranking and targeting requires evaluation of the perceived magnitude of the quality
impairment of a receiving water in its geographic and economic context. The CWA requires that
the priority ranking of water quality-limited waters take into account the severity of pollution and
the uses to be made of such waters. The TMDL Program Guidance (EPA, 1991a) suggests
additional factors, including risk to human health and aquatic life and the degree of public
interest and support. To do this properly may require the development of monitoring and
sampling programs or special projects, and the use of screening-level models to illustrate which
pollution problems are the most serious.
Once priority impaired or threatened waters are delineated, the TMDL must be developed and
pollution controls implemented for point and nonpoint sources so that water quality ,is restored (or
preserved) and State standards are attained. A TMDL is, essentially, the estimated assimilative
capacity for a water body that tells water quality and land management agencies how much of a
pollutant may enter a water body without affecting designated uses. More data and information
are often necessary to make this estimation. Special monitoring programs may be needed to
facilitate a more complete analysis of pollution sources, and the eventual application, if
necessary, of watershed and/or water quality simulation models.
The TMDL process distributes portions of a water body's assimilative capacity to various
pollutant sources—including natural background sources and a margin of safety—so that the water
body achieves its water quality standards. The analyst may use predictive modeling procedures
to evaluate alternative pollution allocation schemes in the same water body. By optimizing
alternative point and nonpoint source control strategies, the cost effectiveness and pollution
reduction benefits of allocation tradeoffs may be evaluated.
Mathematically, a TMDL is represented as the sum of the wasteload allocations (WLAs) for
point sources, the load allocations (LAs) for nonpoint and natural background sources, and a
margin of safety (MOS).
TMDL = EWLA + ELA + MOS
The MOS is included to account for scientific uncertainty about whether the TMDL reflects the
actual assimilative capacity of the water body. This uncertainty can be caused by insufficient or
poor quality data or a lack of knowledge about the resource and pollutant loadings. The MOS
can also be used to save assimilative capacity for future growth that may contribute additional
pollution to the water body.
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When you cannot be reasonably certain that a TMDL will attain water quality standards in a
given water body—because there is not enough information about the water body itself, pollutant
behavior within the water body, pollutant sources, the effectiveness of pollution controls, etc.—
the TMDL should be developed in phases. This means that, using the information that is
available, a TMDL should be developed and implemented, and then re-evaluated and revised, if
necessary, when better information is at hand.
This phased approach requires well-designed post monitoring programs and periodic re-
assessments of the TMDL allocations. In addition to the allocations for point and nonpoint
sources, a TMDL under the phased approach will establish the schedule or timetable for the
installation and evaluation of point and nonpoint source control measures, data collection, the
assessment for water quality standards attainment, and, if needed, additional predictive modeling.
The scheduling with this approach should be developed to coordinate all the various activities
(permitting, monitoring, modeling, etc.) and involve all appropriate local authorities and State
and Federal agencies. The schedule for the installation and implementation of control measures
and their subsequent evaluations should include descriptions of the types of controls, the expected
pollutant reductions, and the time frame within which water quality standards will be met and
controls re-evaluated.
The phased approach is necessary to use when nonpoint sources contribute to the pollution
problem because of the technical uncertainties of estimating nonpoint source loads, and the
uncertainties about the effectiveness of nonpoint source controls at a specific site. The phased
approach deals directly with these uncertainties by allowing for scheduled re-assessment and
updating of the TMDLs and implementation of nonpoint source control programs. The TMDL
Program Guidance (EPA, 1991a) contains more specific information on the phased approach on
pages 22 and 23.
3. PRIORITIZATIONAND TARGETING
Handbook on geographic targeting, Draft (EPA, 1991b)
Selecting priority nonpoint source projects: You better shop around (EPA,
1989a)
Setting priorities: The key to nonpoint source pollution (EPA, 1987a)
EPA's Office of Water has made targeting of nonpoint pollution sources an integral component of
the TMDL process. Guidelines for assisting in the development of a targeted nonpoint source
program and establishment of priorities at the State and watershed level were defined in Setting
Priorities: The Key to Nonpoint Source Control (EPA, 1987a). This document pinpoints the
programmatic steps required to rank nonpoint source priority areas, describes the set of
prioritization criteria to be considered, and presents several examples of water resources
prioritization. The document also presents an approach for determining the pollutant reduction
needed to achieve water quality goals.
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Many States currently use a formal process for prioritizing water quality-limited waters as part of
their nonpoint source program. Six examples of State prioritization systems are described in
Selecting Priority Nonpoint Source Projects: You Better Shop Around (EPA, 1989a). This
document is intended to help water quality managers develop or refine their own process for
ranking nonpoint source impaired or threatened water bodies, encouraging water quality
managers to adapt these examples to their State nonpoint source management programs where
appropriate. The manual does not provide a "cookbook" approach. The most common criteria
used in the six State prioritization systems that were reviewed were identified and their use in
deciding whether to obligate limited resources for water quality restoration or preservation efforts
were discussed. This document also briefly reviews (1) the priority criteria for the State
Clean Water Strategy which encompasses the Management of Nonpoint Sources of Pollution
(CWA §319), the Individual Control Strategies for Toxic Pollutants (CWA §304), Clean Lakes
(CWA §314), and the National Estuary Program (CWA §320), and (2) the priority grant criteria
for CWA §319(h) funds.
EPA is also preparing a handbook for targeting procedures and approaches for use by Federal,
State, and local agencies in developing their TMDL program agendas. The Handbook on
Geographic Targeting (in Final Draft) summarizes available approaches and recent experience
with water quality targeting. This document describes the four components of geographic
targeting: (1) assessment, (2) ranking, (3) public participation, and (4) selection. Several
illustrative examples are presented to assist water quality managers by providing information on
ongoing programs. The document also facilitates a more integrated approach to targeting by
exploring the relationship among all of the existing water quality programs, including the
Nonpoint Source, §303(d) TMDL, §314, and §319 programs.
4. TOOLS TO ASSESS WATER QUALITY AND ESTIMATE LOAD
ALLOCATIONS
In general, several activities are required to identify and examine the nature of impaired waters
within a particular region, and to identify, examine, and assess the dimensions and causes (i.e.,
point and/or nonpoint sources) of impairment so that the impaired waters can be prioritized and
targeted. Common objectives of a preliminary assessment include identifying the waters within a
region that are water quality limited and characterizing the nonpoint sources, as well as their
contribution to the total load, and their temporal and spatial distribution. To achieve these
objectives, analyses usually begin with a general characterization of the watershed, its water
quality, and the water impairment mechanisms. Analyses may then progress to a more specific
understanding as it becomes necessary to quantify water quality problems by estimating pollutant
loadings. Very often the tools that are used to make a general characterization of a watershed
can also be used to conduct the more specific analyses. The central difference among the stages
of watershed analysis is the amount of data needed and the intensity and rigor of modeling
activities. Both increase as analyses become more complex.
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a. Identifying Impaired Water Bodies
• Survey of Existing Information
- STORE! assistance hotline: (800)424-9067
- EPA mainframe data and tools for watershed assessments. Appendix A in
Workshop on the Water Quality-based Approach for Point Source and Nonpoint
Source Controls Meeting Summary (EPA, 1991c)
- PC Waterbody System User's Guide (Version 3.0) (EPA, 1991d)
One of the most important activities in problem identification consists of a survey and analysis of
existing information. Such information is usually composed of qualitative observations and
quantitative measurements.
Qualitative observations may include specific reports from water quality managers, water body
users, and citizen complaints concerning water quality deterioration such as increased turbidity
within a given season, reduced fishing resources, changes in the eutrophic level and algae
proliferation, and stream bank erosion and channel displacement. These reports are well known
to iocal and regional water managers and their analysis represents the initial steps in identifying
problem waters, estimating the perceived magnitude of the pollution problem, and evaluating the
public concerns.
Quantitative water quality measurements, collected from various monitoring programs, are
usually available on electronic systems and can be readily used in preliminary water quality
assessments. The information may be retrieved from various sources and integrated into several
reporting formats. EPA has several water quality and related information files for the United
States which are available on its main frame computer. These files can be accessed by registered
STORET users with a valid user identification. Analysis of the information contained within the
STORET system can provide a quantitative estimation of water quality conditions and evaluation
of their temporal and spatial variabilities. A brief summary of data bases and the type of water
quality and related information they contain is presented in Table 1. More detailed descriptions
of these files and their structure and use can be found in the corresponding data file manuals.
Also, Appendix A, "EPA Mainframe Data and Tools for Watershed Assessments," in the
Workshop on the Water Quality-based Approach for Point Source and Nonpoint Source
Controls Meeting Summary (EPA, 1991c) summarizes the data bases that are available for use
by the public and how they may be accessed. Example applications are also provided.
Additional water quality information may be retrieved from the Waterbody System (WBS). The
WBS is a PC-based system containing the water quality information that must be reported under
§305(b), §303(d), §314, and §319 of the CWA. If the WBS is not used, the 305(b) Report
contains much of the same information. Recently, a new version of the PC Waterbody System
User's Guide (Version 3.0) (EPA, 199Id) was developed by the Assessment and Watershed
Protection Division of EPA. The WBS uses a standard format and allows for large
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Table 1 - OWOW/AWPD Data Files
Drinking Water Supply File - The Drinking Water Supply File contains information on 8,000 water
supplies that utilize surface waters. Data covers FRDS number, utility name, city,
state, basin, latitude and longitude, stream reach, population served, water volume
used, and locations for plants, intakes, and sources.
Gage - The Stream Gage Data File contains information on approximately 36,000 stream
gaging locations throughout the United States. Information stored includes
locations of gaged streams, stream reach identification, types of data collected,
frequency of data collection, media in which the data is stored, identification of the
collection agency, mean annual flow, and 7 day/10 year flow. The file also
contains estimated flows for all ungaged streams.
City - This file contains data on 53,000 cities, towns, and villages located in the United
States and its possessions. Information on each city includes the city's unique
identification code; the county, state, major and minor river basin, and
congressional district within which ft is geographically located; stream reaches
associated with the city; its latitude and longitude; and its census population data.
Dam - Inventory of 68,000 dams produced by U.S. Army Corps of Engineers which
provides type, ownership, purpose, height, volume, surface area, latitude-longitude,
and stream reach.
Industrial Facilities - The Industrial Facilities Discharge File contains information on 128,000 NPDES
industrial and municipal facilities (active and inactive) useful for environmental
analyses. Data consists of NPDES, DUNS, and Needs A/F numbers with name,
address, basin latitude and longitude, stream reach, flow, SIC codes, discharge
types for facility and pipe level, and industrial category. Indirect discharges to
POTW systems are also included.
CETIS - The Complex Effluent and Toxicity Information System contains bioassay results for
NPDES discharges toxicity tests.
SIWPCA - Streams reported in the Americas' Clean Water STEP report by the Associations of
State and Interstate Water Pollution Control Administrators (ASIWPCA) covering
water quality impairments for 1972, 1982, and 1984 and indexed to the version 1
reach file.
ICAT - Industrial categories used in effluent guidelines studies are grouped with standard
industrial classification (SCI) indexes.
STORET PARM - Information on 13,000 STORET parameters indicating reporting units, media,
CAS registry number, and chemical/biological type.
ODES - The Ocean Data Evaluation System is an extensive system of software for
managing and analyzing marine environmental monitoring data.
PCS - The Permit Compliance System contains NPDES permit compliance, tracking, and
discharge monitoring reports for active permitted facilities.
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Table 1 - OWOW/AWPD Data Files (continued)
Reach File - The River Reach File provides hydrologic connectivity between geographic locations
and historical data created for the express purpose of performing hydrologic routing
for modeling programs. The Reach File, Version 1, contains 68,000 stream reaches
covering 100% of the continental U.S. and is indexed with STORET, IFD, drinking
water supplies, stream gages, and fish kills. Version 3 covers 80% of the U.S. and
provides hydrologic linkages for 3.5 million reaches based on the USGSW DLG data.
STORET-BIOS - A component of STORET containing distribution, abundance, physical condition,
and habitat description of aquatic organisms. These are integrated with the water
quality file and linked to the reach file, PCS, IFD, and Gage files.
STORET-USGS Flow - Contains daily stream observations of stream flow and miscellaneous water
quality at USGS gaging stations. These data represent more than 695,000 water
years for over 29,000 gages.
STORET-WQ - The agency's water quality system containing physical, chemical, and biological
parameters. More than 800 monitoring organizations have provided 175 million
parametric observations from 700,000 sampling locations for surface water, ground
water, fish tissue, and sediment. The sample locations are indexed to the reach file
IFD, GAGE, and drinking water file with a PCS interface.
STORET-Tissue - Tissue sample results cover over 530 parameters including metals, organics, and
pesticides specific to species, tissue types, length, weight, and sex. These data
and stations are integrated with the water quality file and indexed to the reach file
with indexes to IFD, Gage, drinking water files, and the PCS interface.
STORET Form 2C - Priority pollutant data reported by NPDES second round permits are in STORET
referenced by the permit number and can be integrated with the water quality data
and PCS data with the PCS/STORET interface.
WBS - The Waterbody System data base contains water quality assessment information
collected by states for 305(b) reporting. These data serve as an inventory of each
state's navigable waters that have been assessed.
quantities of water quality information to be summarized and reported according to the
requirements of CWA §305(b). The WBS User's Guide provides detailed information for
operating the various system options, including new data entry, assessment updates, and report
generation. The system was developed to improve the quality and consistency of water quality
reporting and to reduce the burden of report preparation. It is also intended to enhance water
quality analytical capabilities by making it possible to compare assessment data over time and
space.
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Analysis of Water Quality Information
Water quality analysis system: Seminar documentation (EPA Region III, 1991)
PCS data base management system design, PCS Generalized retrieval manual
(EPA, 1987b)
Managers guide to STORET (EPA, 1982)
Methodologies for estimating NPS impacts on water quality from development
(EPA Region V, 1991)
Statistical methods for environmental pollution monitoring (Gilbert, 1987)
Evaluation of some approaches to estimating non-point pollutant loads for
unmonitored areas (Richards, 1990)
DESCON user's manual, Draft (Rossman, 1992)
Developing a monitoring system (EPA, 1991e)
Several technical tools are needed to analyze available water quality information as part of a
water quality assessment within the TMDL framework. These tools may range from simple
statistical summaries of water quality data to more complex graphical representation and trend
and excursion analyses. In addition to water quality data files, several interactive analysis
procedures were developed by EPA to enable users to access, retrieve, and analyze the water
quality and related information contained in EPA's main frame computer. Table 2 lists the water
quality analysis systems most commonly used. Several system user guides and operation manuals
are available from EPA, including the Managers Guide to STORET (EPA, 1982), and the PCS
Generalized Retrieval Manual (EPA, 1987b). Other system guides were compiled in the Water
Quality Analysis System: Seminar Documentation (EPA Region III, 1991).
The DESCON system is another tool that may be useful to water quality managers when
analyzing various water quality parameters to identify impaired and/or threatened waters. It
provides automatic linkages to EPA's STORET system for retrieving stream flow and water
quality data. These data are necessary to perform a long-term simulation of the daily loading of
a pollutant that a receiving water can accomodate without violating standards. DESCON's
Option 1 retrieves daily stream flow data, compiled by the U.S. Geological Survey (USGS), from
the EPA's STORET data base system. Option 2 retrieves water quality data from STORET.
Option 3 can perform various statistical analyses on the water quality data extracted from
STORET to indicate trends. This system cannot be used to perform nonpoint source load
allocation studies at this time. The DESCON User's Manual (EPA, 1992) is currently being
updated. It should be finalized by the summer of 1992. More information on this water quality
package may be obtained directly from Lewis A. Rossman, EPA Risk Reduction Engineering
Laboratory, Cincinnati, Ohio (513/569-7603).
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Two useful references on various methods and procedures for interpretation of water quality data
include Statistical Methods and Procedures for Environmental Pollution Monitoring (Gilbert,
1987), and Evaluation of Some Approaches to Estimating Non-Point Pollutant Loads for
Unmonitored Areas (Richards, 1990). Additional references can be found in Methodologies for
Estimating NPS Impacts on Water Quality from Development (EPA Region V, 1991).
Statistical Methods and Procedures for Environmental Pollution Monitoring summarizes the
fundamental sampling design questions typically encountered in environmental studies and
presents numerous statistical tools for data interpretation. It also presents statistical procedures
for estimating sampling size, duration, and geographical coverage. Standard statistical methods
for describing water quality conditions (e.g., mean, median) and evaluating the magnitude of
temporal and spatial trends are presented along with selected specialized procedures for
addressing problems related to the limitations common to environmental data sets (e.g., non-
normality, seasonality, censoring).
Table 2 - OW Mainframe Interactive Analysis Systems
ASIWPCA Interactive program providing information on stream use impairment
CITY Interactive program providing overview information on cities
DAMR Interactive program providing information on dams in the U.S.
DFLOW Interactive program providing daily flows at gages and selected flow statistics
DXLIST Interactive program providing information on dioxin
EDDM Interactive program for graphically displaying locations of monitoring activities, PCS,
and WQ data
FLOW Interactive program providing information on gage mean flow, 7Q10 low flows, and
daily flows
ICAT Procedure to list industrial categories and related SIC codes in IFD File used by ITD
IFDPLOT Interactive program to set up graphical displays of Facility data
IFDRET Interactive program for generating standard tables of information from IFD
IPS5 Interactive procedure for generating reports from STORET, PCS, and IHS files
ISR Interactive, generates selected STORET and IFD reports and DO model using PCS
DMR data
MDDM Interactive mapping system for the Reach File, Facility, WQ, and WBS data
PARM Interactive program for providing information on STORET parameters
PATHSCAN Retrieval of information on hydrological streampaths from NPDES discharge
locations
RCHDAT Interactive program for retrieving reach, streamflow, and discharger data
RCHRET Interactive procedure for generating reach trace Auxfiles for plotting or export
RPA3 Reach pollutant assessment software providing reports using STORET, PCS, TRIS,
and IHS data
SIC Interactive program to obtain SIC codes and descriptions used in the IFD File
SITEHELP Interactive graphical and text retrieval of stream referenced data using IHS,
STORET, and PCS files
STRAUX Procedure which generates a STORET AUXFILE for selected reach number
USE Interactive program for summarizing WQAB procedure usage for given user
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Evaluation of Some Approaches to Estimating Non-Point Pollutant Loads for Unmonitored
Areas examines data extrapolation techniques. Six extrapolation procedures and their application
to unmonitored sites were evaluated using the Heidelberg College Water Quality Laboratory data
sets. In general, three procedures (inter-basin ratios, C-factor, and discharge) were found to be
more reliable than the regression-based approaches. However, the accuracy of these procedures
was found to decrease significantly when applied to watersheds different in size from the control.
The author also suggests that a paired watershed approach, not evaluated in this study, might be
useful for extrapolating nonpoint source loads to unmonitored sections of a drainage basin. The
latter approach is addressed in "Developing a Monitoring System," a paper that was presented
at the Nonpoint Source Watershed Workshop (EPA, 1991e).
The Role of Water Quality Monitoring
Surface water monitoring program guidance, draft (EPA, 1990a)
Rapid bioassessment protocols for use in streams and rivers: Benthic
macroinvertebrates and fish (EPA, 1989b)
Nonpoint source monitoring and evaluation guide, draft (EPA, 1987)
Methodologies for estimating NPS impacts on water quality from development
(EPA Region V, 1991)
Biological criteria for the protection of aquatic life: Volume III standardized
biological field sampling and laboratory methods for assessing fish and
macroinvertebrate communities (Ohio EPA, 1989)
The nonpoint source manager's guide to water quality monitoring (Coffey and
Smolen, 1990)
Guidelines for the monitoring of urban runoff quality (Sonnen, 1983)
Methods for evaluating stream, riparian, and biotic conditions (Platts et al.,
1983)
Information from monitoring programs may be used at various stages of the TMDL process,
including identification of impaired or threatened waters, estimation of nonpoint source loadings,
calibration and verification of watershed and water quality models, and evaluation of the
effectiveness of pollution management practices. Analysis of available water quality data usually
reveals data gaps and needs for additional monitoring activities. It also assists in defining the
objectives of the monitoring programs, the spatial distribution of monitoring stations, the set of
parameters to be monitored, and the frequency and duration of the monitoring program.
While it may be unnecessary to collect additional data for a preliminary assessment of impaired
waters, special monitoring activities may be required to properly quantify nonpoint source
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loadings to a water body, to calibrate and verify models, and to verify the effectiveness of best
management practices to control nonpoint source pollution. In addition, once TMDLs have been
established for a given water body, monitoring programs are recommended to document changes
in water quality and provide basic information for future reviews and updates of existing
TMDLs. This type of follow-up monitoring is required for a phased TMDL.
Well-designed ambient water quality monitoring can indicate when and where water quality is
impaired by providing the general chemical, physical, and biological data that reflect the water
and habitat quality conditions of a water body. There are several useful publications regarding
the development and design of monitoring programs for watershed management and nonpoint
source pollution assessment projects. References, in addition to those described below, can also
be found in Methodologies for Estimating NFS Impacts on Water Quality from Development
(EPA Region V, 1991).
The Nonpoint Source Manager's Guide to Water Quality Monitoring (Coffey and Smolen,
1990), discusses monitoring objectives and water quality variables, presenting guidelines to help
decision makers plan for and design an appropriate monitoring program. Two levels of nonpoint
source monitoring, which may be designed according to the objectives, time and resources, and
equipment necessary, are presented. Level 1 monitoring focuses on the general condition of
water bodies monitored in terms of easily measured variables. Such a program may be used to
identify or confirm general problems and determine violation frequencies. Level 2 monitoring
builds on information obtained in Level 1 and consists of more comprehensive data collection,
often requiring greater resources.
Guidelines for the Monitoring of Urban Runoff Quality (Sonnen, 1983) presents storm water
monitoring requirements as they relate to project objectives. The key objectives that are
reviewed include problem identification, alternative solutions, design, regulatory compliance,
operational performance, and research monitoring. This document reviews a number of
monitoring programs (Denver, Houston, Chicago, San Francisco, and the National Urban Runoff
Program), examines practical design and management considerations, and evaluates the associated
costs. Monitoring program components include field sampling, laboratory analysis, data
interpretation, and inflation costs. Rudimentary statistical guidance for selecting sample size and
analyzing data is also provided.
The Surface Water Monitoring Program Guidance (EPA, 1990a) was developed by the EPA
in response to increasing needs and demands for improved water quality monitoring. This
document targets EPA and State decision makers and provides both technical and programmatic
considerations for surface water monitoring. Some of the key topics reviewed include screening
for existing and emerging problems and analysis of effective monitoring. Numerous case studies
from across the United States are provided to demonstrate typical examples of current monitoring
programs.
The Nonpoint Source Monitoring and Evaluation Guide (EPA, 1987) makes recommendations
on nonpoint source pollution monitoring programs, assessing data needs, and collecting data. It
analyzes water quality monitoring activities according to four objectives: (1) develop baseline
information, (2) generate sufficient data for trend analysis, (3) develop/verify models, and (4)
investigate single incidents or events. This draft document provides an overview of NPS
pollution problems as well as a summary of sampling requirements and basic statistical
procedures.
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The Rapid Reassessment Protocols for use in Streams and Rivers: Benthic
Macroinvertebrates and Fish (EPA, 19895), was developed by EPA to assist State programs in
conducting cost-effective biological assessments. Three macroinvertebrate and two fish protocols
are presented. Benthic Rapid Bioassessment Protocol I and Fish Rapid Bioassessment Protocol
IV are cost-effective screening procedures that provide some supporting data; Benthic Rapid
Bioassessment Protocol II can help set priorities for more intensive evaluations; and Benthic
Rapid Bioassessment Protocol III and Fish Rapid Bioassessment Protocol V are progressively
more rigorous and provide more confirmational data, but also require more resources. The
protocols advocate an integrated assessment, comparing habitat and biological measures with
empirically defined reference conditions. They can be used to determine if a stream is supporting
its designated life use, characterize the existence and severity of use impairment, help identify the
sources and causes of impairment, evaluate the effectiveness of control actions, support use
attainability studies, and characterize regional biotic components. A procedure for evaluating
habitat is also presented in this document.
The Ohio Environmental Protection Agency has developed a biosurvey program that includes
biological sampling of macroinvertebrates and fish, and subsequent habitat evaluation as it relates
to the fish community. Biological Criteria for the Protection of Aquatic Life: Volume III.
Standardized Biological Field Sampling and Laboratory Methods for Assessing Fish and
Macroinvertebrate Communities (Ohio EPA, 1989) address monitoring of resident biota as part
of the water quality assessment program to increase the probability of detecting sporadic events
(e.g., spills, nonpoint sources) or other highly variable impacts missed by traditional chemical
and toxicological monitoring. The Invertebrate Community Index is a measure used by Ohio
EPA to accurately evaluate water quality effects in rivers and streams. The ICI is comprised of
ten community metrics or attributes including total number of taxa, total number of mayfly taxa,
total number of caddisfly taxa, total number of dipteran taxa, percent mayflies, percent
caddisflies, percent tribe Tanytarsini midges, percent other dipterans and non-insects, percent
tolerant organisms, and total number of EPT (Ephemeroptera, Plecoptera, and Trichoptera) taxa.
The scoring system evaluates each sample against a reference database of 247 undisturbed sites
throughout Ohio.
The U.S. Forest Service has also developed standardized techniques and methods for measuring
stream, riparian, and biotic conditions for stream and river analysis. These techniques are
compiled in the Methods for Evaluating Stream, Riparian, and Biotic Conditions (Plaits, et
al., 1983). This report also addresses the validity of the recommended measurements and
information based on their expected accuracy.
b. Analyzing Pollution Sources
The water quality monitoring and data interpretation methods presented in the previous section
are intended to facilitate the identification of water quality-limited'waters. Once problem waters
have been identified, the next steps are to survey potential pollution sources and analyze pollution
causes and delivery mechanisms. This may include characterizing/assessing the watershed,
simulating point and nonpoint pollution sources on a watershed basis, and modeling receiving
water quality response.
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Watershed Characterization
U.S. Geological Survey National Cartographic Information Center, 507 National
Center, Reston, VA 22092, phone: 703/860-6045
Watershed screening methodology - Savannah River Basin application (EPA
Region IV, 1992)
Workshop proceedings on remote sensing and GIS applications to nonpoint
source planning (EPA, 1991g)
Introductory digital image processing (Jensen, 1986)
A land use land cover classification system for use with remote sensor data
(Anderson et al., 1976)
Spatial analysis using GIS: Seminar workbook (Goodchild and Brusegard,
1989)
Integration of GIS, digital elevation data, and remote sensing for a hydrologic
model (Lee et al., 1990)
The use of a GIS to track the impact of Virginia Chesapeake Bay Agricultural
Nonpoint Source Program (Shanholtz et al., 1988)
BMP effectiveness evaluation using AGNPS and GIS (Hession et al., 1989)
Annual estimation of nitrogen in agricultural runoff (Yagow et al., 1990)
Hydrologic/water quality modeling in a GIS environment (Shanholtz et al. 1990)
VirGIS, Dr. Vernon Shanholtz, phone: 703/231-5843
EPA monitoring systems laboratory, phone: 702/798-2100
Agricultural nonpoint source pollution (AGNPS) model (Dr. Robert Young,
phone: 612/589-3411)
Compendium of watershed-scale models for TMDL development (EPA, 1992a)
Airphoto inventories for pinpointing nonpoint sources (Perchalski, 1989)
Watershed characterization includes delineating hydrologic boundaries, identifying soil and
topographic features, mapping the type of land use/land cover, defining population patterns,
surveying point and nonpoint sources of pollution, etc. Several data sources may need to be
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Page 14
consulted to retrieve all of the necessary information. If possible, in addition to any site-specific
information that is available at State and local agencies, U.S. Geological Survey (USGS)
topographic maps, local zoning maps, agricultural reports on crop type and area, hydrologic
information from USGS gaging stations (on EPA's main frame computer files), National land use
data files (USGS and the Soil Conservation Service NRI land use data files), the National
Weather Service weather data, demographic information from U.S. Bureau of Census, water
supply and other usage (local surveys, EPA STORET files), and the characteristics and
geographical distribution of permitted dischargers in the watershed (STORET) should be used.
The U.S. Geological Survey National Cartographic Information Center, 507 National
Center, Reston, VA 22092, phone: 703/860-6045, provides a nationwide information service
for cartographic data of the United States. Information about maps and charts, aerial and satellite
photographs, and map data in digital form is available at the center.
The EPA main frame can meet many of the needs and goals of watershed analysis and nonpoint
source characterization, taking advantage of available national data bases on stream flow and
hydrologic parameters, land use distribution, point sources, and water quality measurements.
Recent and ongoing system enhancements of several interactive procedures provide significant
capability to conduct integrated point and nonpoint source assessments on a regional and
watershed level.
Preliminary testing of these procedures for application in the TMDL development process are
summarized in a draft report Watershed Screening Methodology - Savannah River Basin
Application (EPA Region IV, 1992). The techniques employed by this methodology can
produce a snapshot of water quality conditions at a regional and watershed level. The regional
assessment addresses river basin systems and examines watershed characteristics, general
hydrology and water resources, and statistical summaries and trends of water quality indicators.
This assessment relies on readily available information stored on EPA's computer system. The
methodology is designed to assist in identifying, on a large scale, areas where water bodies are
impaired or threatened and to provide a preliminary evaluation of potential point and nonpoint
pollution sources. The watershed assessment focuses on water quality-limited areas or sub-
watersheds identified at the regional assessment level. It uses simple simulation models to
generate area or sub-watershed wide pollutant loadings and evaluates the contribution of each
pollution source to the total load. To facilitate application of the watershed assessment,
procedures for linking the pollution load simulation model to data bases on the EPA main frame
are under development. This screening methodology was developed to assist the water quality
manager perform a rapid screening application of water quality problems at a regional and
watershed level. The key benefit is the integration of all pollution sources and related factors in
the analysis and the optimum usage of readily available data. In addition to identification of
water quality-limited waters, analysis of pollution sources, and development of decision criteria
for the prioritization and targeting process, the methodology can assist in defining additional data
needs and designing monitoring programs.
Several TMDL development activities rely on spatial analyses, especially when investigating the
significance of nonpoint source pollution loads from specific land uses or activities, or assessing
the impacts of temporal changes in land use patterns on water quality. Spatial information, such
as land use/land cover and its changes over time may be easily generated from aerial photography
or satellite imagery. Although most applications of aerial photographic methods and satellite-
based remote sensing techniques were directed toward inventory and assessment of natural
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resources to derive information for management decisions, current technological advances in
these methods can provide valuable supplementary data sources to rapidly perform screening
level assessments for TMDL development.
Airphoto Inventories for Pinpointing Nonpoint Sources (Perchalski, 1989) describes and
illustrates the techniques used to develop a nonpoint source inventory in an application to the
Tennessee River watershed to derive animal waste, soil loss, and agricultural chemical
information. The approach used in this application consists of (1) project planning, (2) material
acquisition, (3) information extraction, (4) field checks, (5) data transfer, and (6) data
interpretation and reporting. The cost of applying the six-step approach to a one million acre
watershed was evaluated at about 20 cents per acre. Example applications of remote sensing
techniques to surface mapping (i.e., the creation of a land cover map for Lake County, Illinois,
wetland delineation, and analysis of the spatial distribution of suspended sediment within lakes
and reservoirs) were presented through other papers in the Workshop Proceedings on Remote
Sensing and GIS Applications to Nonpoint Source Planning (EPA 1991g).
The EPA Monitoring Systems Laboratory (EMSL), Las Vegas, has extensively employed remote
sensing techniques to assess lake water management problems. These techniques are used by
EMSL to produce a wide range of management products, such as aerial photography prints,
digital image maps, and geographical information systems data bases, that may be used in the
TMDL development process.
Remote sensing information can be converted into vector-based GIS system data bases for further
data processing and modeling to evaluate nonpoint source pollution loadings. It should be noted,
however, that the application of remote sensing and GIS techniques to watershed analysis requires
both specialized software and hardware, in addition to well-trained personnel to set up and
operate the system, process watershed information, and interpret the results. EMSL can provide
some guidance with these applications (phone: 702/798-2100).
Researchers at the Illinois State Water Survey have used satellite images, scanned aerial photos,
and other spatial analysis techniques, including the geographical information system and digital
elevation data, to run the Agricultural Nonpoint Source Pollution (AGNPS) Model. Application
of this approach to two Illinois watersheds indicated that the approach is technically and
economically feasible. Dr. Robert Young (phone: 612/589-3411) can provide more
information on applications of the AGNPS model throughout the country. A brief summary of
the model itself is also available in the Compendium of Watershed-Scale Models for TMDL
Development (EPA, 1992a), which was recently compiled.
The Virginia Division of Soil and Water Conservation (DSWC) has used a geographical
information system (VirGis) as a component of its nonpoint source pollution control program.
The objectives of the VirGis application are to develop (1) procedures to identify, prioritize and
target land areas needing improved nonpoint source pollution control measures, (2) procedures to
evaluate the effectiveness of nonpoint source pollution control programs and management
strategies, and (3) an Information Support System to assist in state wide management of natural
resources. Researchers at the Virginia DSWC have published numerous reports, which are listed
in the box on page 13, describing experience, assessment procedures, and applications of VirGis
to meet the three objectives above. To obtain information on the VirGIS effort, contact Dr.
Vernon Shanholtz (ISSL), Department of Agricultural Engineering, 106-A Faculty Street,
Blacksburg, VA 24061-0535 (phone: 703/231-5843).
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The Workshop Proceedings on Remote Sensing and GIS Applications to Nonpoint Source
Planning (EPA 1991g) also addresses the application of remote sensing and GIS techniques to
watershed management and nonpoint source pollution assessment. This document is a collection
of selected papers regarding specific applications of remote sensing, GIS, and other techniques
(i.e., the Digital Elevation model and watershed simulation models) to nonpoint source problems.
Other references that can provide basic remote sensing and GIS fundamentals are cited in the
various papers.
Watershed Simulation Models
Compendium of watershed-scale models for TMDL development (EPA, 1992a)
Modeling of nonpoint source water quality in urban and non-urban areas (EPA,
19905)
River basin validation of the water quality assessment methodology for
screening nondesignated 208 areas. Volume II: Chesapeake Sandusky
Nondesignated 208 screening methodology demonstration (Dean et al., 1982)
Watershed simulation models may be used in the TMDL process to support a number of
objectives and decisions. Typical project objectives that would require application of a
watershed-scale model include (1) identifying problem areas or potential nonpoint sources in the
watershed and characterizing the magnitude and variability, in time and space, of these sources;
(2) comparing watersheds and assisting in the prioritization and targeting process; (3) providing
the information necessary for receiving water quality analysis and modeling; (4) providing
information for siting and designing control practices; (5) estimating the cost and performance of
nonpoint pollution control alternatives; and (6) evaluating their relative impacts on water quality.
A wide variety of simulation models are available to evaluate both point and nonpoint pollution
loads from watersheds containing multiple point and nonpoint sources and land uses. Although
these models were not specifically designed to work within the TMDL process, many of their
capabilities can be directly applied to comprehensive water quality-based assessments. Several of
these models are Federally supported and can be acquired from the following agencies:
• Center for Exposure Assessment Modeling, U.S. EPA, College Station
Road, Athens, Georgia, phone: 404/546-3549. .
• National Center, U.S. Geological Survey, Reston, Virginia 22092,
phone: 703/648-4000.
• The Hydrologic Engineering Center (HEQ, U.S. Corps of Engineers,
609 Second Street, Davis, California 95616, phone: 916/756-1104.
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Grassland, Soil and Water Research Laboratory, U.S. Department of
Agriculture, Temple, TX 76502, phone:. 817/770-6502.
North Centra] Laboratory, U.S. Department of Agriculture, Morris,
Minnesota 56267, phone: 612/589-3411.
Federally Distributed
Watershed-scale Models
Dept. of Agriculture
Agriculture Research
Service
Geological Survey
Corps of Engineering
AGNPS (Agricultural
Nonpoint Source
Pollution Model)
DR3M-QUAL (Distributed
Routing Rainfall Runoff Model
- Quality)
STORM (Storage, Treatment,
Overflow, Runoff Model)
Potential applications of watershed models in
the TMDL process were briefly discussed at
the Workshop on the Water Quality-based
Approach for Point and Nonpoint Source
Controls, held in Chicago in June, 1991. In
response to a number of recommendations
formulated in this workshop, the EPA's
Office of Water compiled a Compendium of
Watershed-Scale Models for TMDL
Development (EPA, 1992a). This
compendium reviews 22 watershed models
which can be used to assist in the TMDL
development process. Simulation
capabilities, modeling performance, data
requirements, and ease of use are described
for each model. In addition, an exhaustive fact sheet for each model was prepared containing
information on the model developer and distributor and a description of model components,
limitations, and published applications. The compendium presents a brief comparison of each
model's characteristics and discusses pertinent criteria to consider in selecting a watershed model
for screening applications.
EPA's Office of Research and Development has also sponsored a review of selected watershed-
and field-scale models with potential application in water quality analysis and TMDL
development. This review is entitled Modeling of Nonpoint Source Water Quality in Urban
and Non-urban Areas (EPA, 1990b) and describes 11 computer-based models, in addition to
several other simple nonpoint source evaluation methodologies. Several case studies where
simulation models have been used to assess nonpoint source pollution problems are described and
recommendations for urban nonpoint runoff quality modeling are presented.
Earlier EPA-sponsored work developed a screening methodology to assess water quality problems
in areas not covered under Section 208 of the Federal Water Pollution Control Act Amendments
of 1972. The ensuing write up was entitled River Basin Validation of the Water Quality
Assessment Methodology for Screening Nondesignated 208 Areas (Dean et al., 1982). The
study incorporates nonpoint source loading factors developed by the Midwest Research Institute
(MRI) to estimate the quantities of different diffuse loads entering receiving water bodies from
various nonpoint sources. The report demonstrates how a combination of simple techniques
could be used to identify water quality problems. It also describes the successful application of
the nondesignated 208 screening methodology under field conditions in five river basins
(Sandusky River, Chester River, Patuxent River, Ware River, and Occoquan Reservoir).
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Receiving Water Quality Models
Water Quality Assessment: A Screening procedure for Toxic and Conventional
Pollutants in Surface and Ground Water: Part I (Revised 1985) (EPA, 1985a)
Water Quality Assessment: A Screening procedure for Toxic and Conventional
Pollutants in Surface and Ground Water: Part II (Revised 1985) (EPA, 1985b)
Watershed-scale models allow estimation of pollutant loadings to a receiving waterbody and the
analysis of pollution source characteristics, magnitudes, and variability over time and space.
Receiving water quality models, on the other hand, examine the transport and fate of pollutant
loadings in river, lake, and estuarine environments. Although the majority of water quality
models were developed for a wide range of applications, dealing primarily with point sources,
waste load allocations, and evaluation of assimilative capacity of receiving water bodies, their use
in analyzing nonpoint source pollution load allocations and assisting in TMDL development is
well accepted. They are a valuable tool for assessing the causal relationships between changes in
nonpoint source pollution loads due to alterations of land use patterns, implementation of
watershed management programs, or point source control and the effects on receiving water
quality.
The results of water quality models provide pollutant
distributions in time and space that may be compared to a
specific water quality standard or criterion to determine
whether violations are likely to occur. For nonpoint
source load allocation studies, water quality models rely
on inputs from the watershed analysis to properly account
for nonpoint source loadings. It is common practice to
couple a watershed model and a water quality model to
provide an integrated analysis of point and nonpoint
source pollution and facilitate comprehensive watershed
management.
Several water quality models are currently supported by
EPA's Athens Environmental Research laboratory (see
box). These include, among others, QUAL2E, the
Water Quality Simulation Program (WASP4), EXAMS,
and SMPTOX. The QUAL2E model can be applied for
temperature, oxygen demand, nutrients, phytoplankton,
and other user defined problems in rivers and well-mixed
lakes. The WASP4 model is a general numeric model
intended to provide a flexible temporal and spatial
transport of pollutants in rivers, lakes, estuaries, and
coastal waters. SMPTOX and EXAMS are particularly
appropriate for screening application and identification of
potential water quality problem areas.
CEAM Supported
Models
Model Name Version No.
DYNTOX
EXAMSII
HSPF
MINTEQA2/PRODEFA2
PRZM
QUAL2E-UNCAS
SWMM
WASP4/TOXI/EUTRO
DYNHYD5
GCSOLAR
FGETS
CORMIX1
CORMIX2
DBAPE
CLC Database
RUSTIC
MULTIMED
HYDRO2D-V
SED2D-V
HYDR03D
RTVMOD
.1.0
2.94
9.01
3.00
1.00
3.11
4.2
4.22
5.02
1.10
1.00
1.00
2.00
1.05
2.00
.
-
-
-
-
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Page 19
Book
II.
ill.
IV.
Among the simple models or
methodologies that are supported by EPA
are those found in Parts I and II of Water
Quality Assessment: A Screening
Procedure for Toxic and Conventional
Pollutants in Surface and Ground
Water (EPA, 1985a and b). These
models can be used to compute pollutant
levels in rivers, streams, estuaries, and
surface impoundments. Computations can
be applied to assess dissolved oxygen,
toxic substances, metals, sediment
accumulation in impoundments,
eutrophication, and estuarine flushing
time.
It should be noted that it is preferable to
use the simplest water quality model that
can account for the governing mechanisms
affecting the targeted water body.
However, selection of a model that is too
simple may result in inaccurate predictions
of water quality conditions, especially
when examining pollution load reduction
scenarios. These inaccuracies may exist
even if the model is properly calibrated
using existing data. On the other hand,
selection of a model that is too complex
can misdirect study resources, delay the
study, and be unnecessarily expensive.
Also, uncertainty may increase because of •
extra "free" model parameters that cannot
be estimated with available data. General
guidelines and specific procedures for
selecting a water quality model for a given
application are addressed in the Technical
Guidance Manuals for Performing
Waste Load Allocations, a set of nine
volumes describing approaches for
allocating waste loads in rivers, streams,
lakes and impoundments, and estuaries. The pollutants addressed are biochemical oxygen
demand/dissolved oxygen, nutrients, and toxic substances. Several case studies illustrating model
selection and applications are also presented. In contrast with watershed-scale models, no
specific reviews and evaluation of water quality models are available; readers may refer directly
to any model documentation which can be procured from the EPA Environmental Research
Laboratory in Athens, Georgia (a full address is on page 16 of this document).
VII.
VIII.
IX.
Technical Guidance Manuals for
Performing Waste Load Allocations
Title
General Guidance
Streams and Rivers
Biochemical Oxygen Demand/Dissolved
Oxygen
N utrient/Eutrophication
Toxic Substances
Simplified Analytical Method for
Determining NPDES Effluent
Limitations for POTWs Discharging
into Low-Flow Streams
Estuaries
Estuaries and Waste Load Allocation
Models
Application of Estuarine Waste Load
Allocation Models
Use of Mixing Zone Models in
Estuarine Waste Load Allocations*
Critical Review of Estuarine Waste
Load Allocation Modeling*
Lakes and Impoundments
Biochemical Oxygen Demand/Dissolved
Oxygen
N utrient/Eutrophication
Toxic Substances
Technical Support Document for Water
Quality-Base Toxics Control
Design Conditions
Design Flow
Design Temperature, pH, Hardness,
and Alkalinity
Permit Averaging
Screening Manual
Biochemical Oxygen Demand/Dissolved
Oxygen
Toxic Organics
Toxic Metals
N utrients/Eutrophication
Innovative Waste Load Allocations*
* not yet available
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5. BEST MAN A CEMENT PRA CTICES (BMPs)
Guide to Nonpoint Source Pollution Control (EPA, 1987)
CZARA Guidance working drafts
The user's Guide to Nonpoint Source Pollution Control (EPA, 1987) outlines the techniques
that are now available for controlling nonpoint source pollution. Additional guidance on nonpoint
source management measures is currently being drafted to comply with the requirements of the
Coastal Zone Act Reauthorization Amendments (CZARA). Chapters two through six, in working
draft form, specify management measures that represent the most effective systems of practices to
prevent or reduce nonpoint source pollution from agriculture, forestry, urban areas, marinas and
recreational boating, and hydromodification. Chapter seven, also in working draft form,
specifies management measures that apply to the protection and restoration of wetlands and
riparian areas, and the use of vegetated treatment systems. Compiled within these drafts is
effectiveness data and cost information about the application of best management practices
(BMPs) across the United States. Numerous Federal and State agencies and programs, such as
the Soil Conservation Service and Cooperative Extension Offices, and universities were the
source of this information. The cost and effectiveness data, for the most part, has not been
synthesized. Nevertheless, these documents could be a valuable reference for making
management decisions about the relative merits of various nonpoint source management options
and for providing a bibliography of additional information sources when they become available.
The Nonpoint Source Control Branch of AWPD will be able to provide copies.
Agriculture
Financial cost effectiveness of point and nonpoint source nutrient reduction
technologies in the Chesapeake Bay Basin - Draft (Camacho, 1991)
Agricultural BMP nutrient reduction efficiencies: Chesapeake Bay Watershed
Model best management practices (Camacho, 1990)
Rural clean water program (EPA, 1990c)
Information on the suitability and design of agricultural BMPs is usually available from County
Soil Conservation Field Offices. Each Field Office has a Field Office Technical Guide that
provides specifications for installation and maintenance of BMPs suitable to that area. Studies on
the costs and pollutant-reduction effectiveness of BMPs are site-specific. Camacho (1991 and
1990) studied the cost-effectiveness and pollutant reduction abilities of BMPs in the Chesapeake
Bay Area. Hallberg and others at the University of Iowa have extensively examined the effects
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Page 21
of BMPs on nitrate and pesticide leaching. The USDA-EPA Cooperative Rural Clean Water
Program (RCWP) has also developed information on the costs and effectiveness of BMPs
implemented in various regions across the country.
Forestry
Water Quality Management Guidelines and Best Management Practices for
Alabama Wetlands (Alabama Forestry Commission, 1989)
California Forest Practice Rules (California Department of Forestry and Fire
Protection, 1991)
A Practical Guide for Protecting Water Quality while Harvesting Forest
Products (Connecticut Resource Conservation and Development Forestry
Committee, 1990)
Forestry Best Management Practices for Delaware (Delaware Forestry
Association, 1982)
Predicted Erosion Rates for Forest Management Activities and Conditions in the
Southeast (Dissmeyer, 1980)
Economic impacts of erosion control in forests (Dissmeyer, 1986)
Most States with commercial Forestry operations have developed Forestry BMP manuals. These
manuals are generally available to the public and can be obtained from State Forestry Divisions.
A few States, particularly in the West, have Forest Practices Acts which require the
implementation of Forestry BMPs on harvest operations. The list above presents several of these
BMP manuals. The references section of the CZARA working draft guidance chapter on
Forestry provides many more. Again, the cost and effectiveness of Forestry BMPs are highly
site-specific. However, the Forest Service has initiated a Stewardship Incentives Program (SIP)
that provides cost-share for BMP implementation.
• Urban Areas
Urban targeting and BMP selection (EPA, 1990d) is an information and guidance manual for
State nonpoint source program staff engineers and managers. It consolidates existing information
and describes a methodology for targeting urban areas for control. It is designed to assist State
and local agency personnel in targeting areas within their jurisdiction for priority in the
development and implementation of nonpoint source management programs. It addresses the
following topic areas: (1) the nature and characteristics of urban runoff, and the types of water
quality problems that are most likely to occur; (2) the types of best management practices that are
appropriate for control of nonpoint source pollutant loads from urban and developing areas, and
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A current assessment of urban best management practices: Techniques for
reducing non-point source pollution in the coastal zone (COG, 1992a)
Watershed restoration sourcebook (COG, 1992b).
Urban targeting and BMP selection (EPA, 1990d)
guidance for their selection; and (3) a procedure for prioritizing urban areas for the application of
controls beyond the baseline measures initially applied on a jurisdiction-wide basis.
Cost and effectiveness of urban BMPs is usually site specific and depends on a variety of factors,
such as land use, soil type, percent of impervious surfaces, and treatment methods already in
existence. Nevertheless, some urban BMP information is transferable and the successes and
ideas of one urban area's experience can be helpful to another. The Metropolitan Washington
Council of Governments has collected effectiveness information for a variety of structural and
nonstructural nonpoint source controls. The Watershed Restoration SourceBook is a manual on
urban watershed restoration techniques. It includes the details of the Six Point Action Plan to
clean up Washington D.C.'s Anacostia River, and contains 14 other papers including Mitigating
the Adverse Impacts of Urbanization on Streams, Developing Effective BMP Systems for Urban
Watersheds, Finding Retrofit Opportunities in Urban Watersheds, and Riparian Reforestation,
among others.
The report, A Current Assessment of Urban Best Management Practices (COG, 1992), is
intended to define the capabilities and limitations of the current generation of BMPs in order to
provide effective stormwater quality management within the coastal zone. It can help to answer
many of the questions that arise when decision makers must choose a particular BMP or
combination of BMP options. Can the BMP reliably remove urban pollutants? How well does
the BMP operate over time? When and where is BMP use feasible? -How much will it cost?
Many States have developed their own BMP guidance for controlling urban stormwater runoff.
This document can be especially useful for those States that have not.
6. FOLLOW-UP MONITORING
Once best management practices have been implemented so that the load allocations specified
within a TMDL can be met, the water quality-based approach requires follow-up monitoring to
ensure that water quality standards are attained. The technical requirements for this type of
monitoring will not differ greatly, if at all, from those described by the references cited in "The
Role of Water Quality Monitoring." The objectives for follow-up monitoring should include (1)
evaluation of water quality, (2) evaluation of BMP effectiveness, and (3) calibration and
verification of any models that were used. Operational performance monitoring would typically
involve long term monitoring, perhaps over the lifetime of the BMP to ensure that its
performance meets the specified design criteria. Long term monitoring would also serve to
document new emerging problems that may arise because of changing conditions in land use
upstream. Paired basin monitoring may also be useful for evaluating the effectiveness of BMPs.
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7. CONTA CTS AND REFERENCES
THE TMDL PROCESS AND NONPOINT SOURCES
EPA. 1991a. Guidance for water quality-based decisions: The TMDL process. U.S.
Environmental Protection Agency, Office of Water, Washington, D.C. EPA 440/4-91-
001.'
PRIORITIZA TION AND TARGETING
EPA. 1991b. Handbook on geographic targeting. Draft. U.S. Environmental
Protection Agency, Office of Wetlands, Oceans, and Watersheds, Washington, D.C.
Prepared by Research Triangle Institute.2
EPA. 1989a. Selecting priority nonpoint source projects: You better shop around. U.S.
Environmental Protection Agency, Office of Water and Office of Policy, Planning and
Evaluation, Washington, D.C. EPA 506/2-89/003.'
EPA. 1987a. Setting priorities: The key to nonpoint source pollution. U.S.
Environmental Protection Agency, Office of Water, Washington, D.C. Prepared by the
Biological and Agricultural Engineering Department at North Carolina State University.1
TOOLS TO ASSESS WATER QUALITY & ESTIMATE LOAD ALLOCATIONS
a. Identifying Impaired Water Bodies
• Survey of Existing Information
STORE! assistance hotline 800/424-9067.
EPA. 199 Ic. EPA mainframe data and tools for watershed assessments. Appendix A in
Workshop on the Water Quality-based Approach for Point Source and Nonpoint Source
Controls Meeting Summary. June 26-28, 1991. U.S. Environmental Protection Agency,
Office of Water. Washington, D.C. EPA 503/9-92-001.'
EPA. 199Id. PC waterbody system user's guide (Version 3.0). U.S. Environmental
Protection Agency, Office of Water, Assessment and Watershed Protection Division,
Washington, D.C. [Contact Jack Clifford, phone: 202/260-3667]
1 Copies of the document can be obtained by calling the Office of Water, phone: 202/260-9112.
- Copies of the document can be obtained by calling Karen Guglielmone, Tetra Tech, Inc. at 202/260-7058.
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Analysis of Water Quality Information
EPA Region III. 1991. Water quality analysis system: Seminar documentation. U.S.
Environmental Protection Agency, Region III, Philadelphia, PA. [ATTN: Publications,
EPA Region III, 841 Chestnut Building, Philadelphia, PA 19107, phone: 215/597-9800]
EPA. 1987b. PCS' data base management system design, PCS Generalized retrieval
manual. U.S. Environmental Protection Agency. [PCS hotline: 202/260-8529]
EPA. 1982. Managers guide to STORET. Washington, D.C., Government Printing
Office Publication 1982-373-096. [STORET assistance hotline 800/424-9067]
EPA Region V. 1991. Methodologies for estimating NFS impacts on water quality from
development. U.S. Environmental Protection Agency, Watershed Management Unit,
Water Division, Region V. by Tetra Tech, Inc.2
Gilbert, R.O. 1987. Statistical methods for environmental pollution monitoring. Van
Nostrand Reinhold Company, New York, -[phone: 212/254-3232 or 1800/926-2665 for
purchase, pricing, and availability]
Richards, R.P. 1990. Evaluation of some approaches to estimating non-point pollutant
loads for unmonitored areas. Water Resources Bulletin, 25(4): 891-904.2
Rossman, L.A. 1992. DESCON user's manual. Draft. Water and Hazardous Waste
Treatment Research Division. Risk Reduction Engineering Laboratory, Office of
Research and Development, U.S. Environmental Protection Agency, Cincinnati, OH.
[phone: 513/569-7603]
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• The Role of Water Quality Monitoring
EPA. 1990a. Surface water monitoring program guidance. Draft. U.S. Environmental
Protection Agency, Office of Water, Washington, D.C.
EPA. 1989b. Rapid bioassessment protocols for use in streams and rivers: benthic
macroinvertebrates and fish. U.S. Environmental Protection Agency, Office of Water.
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EPA. 1987. Nonpoint source monitoring and evaluation guide. Draft. U.S.
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Division, Nonpoint Source Branch. Washington, D.C.
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EPA Region V. 1991. Methodologies for estimating NFS impacts on water quality from
development. U.S. Environmental Protection Agency, Watershed Management Unit,
Water Division, Region V. by Tetra Tech, Inc.2
Ohio Environmental Protection Agency. 1989. Biological criteria for the protection of
aquatic life: volume III. standardized biological field sampling and laboratory methods
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quality monitoring. Water Quality Group, Department of Biological and Agricultural
Engineering, North Carolina State University, Raleigh, NC. For U.S. Environmental
Protection Agency, Region VII, Kansas City, KS.2
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• Watershed Characterization
Anderson, J.R., E.E. Hardy, J.T. Roach, and W.E. Witmer. 1976. A land use land
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EPA. 199If. U.S. Environmental Protection Agency - Region V and Northeastern
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planning. Workshop Proceedings. Chicago, Illinois. October 1-3, 1990. [Distributed
by The Terrene Institute, Washington, D.C., phone: 202/833-8317.]
Goodchild, M.F. and D. Brusegard. 1989. Spatial analysis using CIS: Seminar
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Hession, W.C., K.L. Huber, Mostaghimi, S., V.O. Shanholtz, and P.W. McClellan.
1989. BMP effectiveness evaluation using AGNPS and CIS. Written for presentation at
the 1989 International Winter Meeting sponsored by the American Society of Agricultural
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remote sensing for a hydrologic model. Proceedings of 1990 ASCE Hydraulics
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Shanholtz, Dr. Vernon. VirGIS. Department of Agricultural Engineering, 106-A Faculty
Street, Blacksburg, VA 24061-0535, phone: 703/231-5843.
Shanholtz, V.O., C.J. Desai, N. Zhang, J.W. Kleene, and C.D. Metz. 1990.
Hydrologic/Water Quality Modeling in a CIS Environment. Written for presentation at
the 1990 International Summer Meeting sponsored by the American Society of
Agricultural Engineers, Columbus, OH, June 24-27, 1990. Paper No. 90-3033.2
Shanholtz, V.O., N. Zhang, E.R. Yagow, C.J. Desai, and J.M. Flagg. 1988. The use of
a CIS to track the impact of Virginia Chesapeake Bay Agricultural Nonpoint Source
Program. Written for presentation at the 1988 International Winter Meeting of the
American Society of Agricultural Engineers, Chicago, IL, December 13-16, 1988. Paper
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EPA. 1992a. Compendium of watershed-scale models for TMDL development. Draft.
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Perchalski, F.R. 1989. Airphoto Inventories for Pinpointing Nonpoint Sources. In: Off-
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St. Louis, Missouri. U.S. Environmental Protection Agency, Washington, D.C.2
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U.S. Geological Survey National Cartographic Information Center, 507 National Center,
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Young. Dr. Robert. Agricultural Nonpoint Source Pollution (AGNPS) Model, phone:
612/598-3411.
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Watershed Simulation Models
Dean, D.J., B. Hudson, and W.B. Mills. 1982. River basin validation of the water
quality assessment methodology for screening nondesignated 208 areas. Volume II:
Chesapeake Sandusky Nondesignated 208 screening methodology demonstration.
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EPA 600/3-82-057b.
EPA. 1992a. Compendium of watershed-scale models for TMDL development. Draft.
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EPA. 1990b. Modeling ofnonpoint source water quality in urban and non-urban areas.
U.S. Environmental Protection Agency, Office of Research and Development,
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Center for Exposure Assessment Modeling, U.S. EPA, College Station Road, Athens,
Georgia, phone: 404/546-3549.
Grassland, Soil and Water Research Laboratory, U.S. Department of Agriculture,
Temple, TX 76502, phone: 817/770-6502.
Hydrologic Engineering Center (HEC), U.S. Corps of Engineers, 609 Second
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National Center. U.S. Geological Survey, Reston, Virginia 22092, phone:
703/648-4000.
North Central Laboratory, U.S. Department of Agriculture, Morris, Minnesota
56267, phone: 612/589-3411.
• Receiving Water Quality Models
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EPA/600/6-85/002a.2
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BEST MANAGEMENT PRACTICES
EPA. 1991: Proposed Guidance Specifying Management Measures for Sources of
Nonpoint Pollution in Coastal Waters. U.S. Environmental Protection Agency. Office of
Water [Will be final in October. Contact Dov Weitman, phone: 202/260-7100]
a. Agriculture
Camacho, Rodolfo. 1991. Financial cost effectiveness of point and nonpoint source
nutrient reduction technologies in the Chesapeake Bay basin (Draft). Interstate
Commission on the Potomac River Basin.2
Camacho, Rodolfo. 1990. Agricultural BMP nutrient reduction efficiencies: Chesapeake
Bay watershed model BMPs. Interstate Commission on the Potomac River Basin.2
EPA. 1990c. Rural clean water program. U.S. Environmental Protection Agency,
Office of Water. EPA 440/4-90-012.2
b. Forestry
Alabama Forestry Commission. 1989. Water quality management guidelines and best
management practices for Alabama wetlands.
California Department of Forestry and Fire Protection. 1991. California forest practice
rules.
Connecticut Resource Conservation and Development Forestry Committee. 1990. A
practical guide for protecting water quality while harvesting forest products.
Delaware Forestry Association. 1982. Forestry best management practices for
Delaware.
Dissmeyer, G.E. 1980. Predicted Erosion Rates for Forest Management Activities and
Conditions in theSoutheast. In: U.S. forestry and water quality: What course in the
80's? Proceedings. Richmond, VA, June 19-20, 1980. Water Pollution Control
Federation, pp. 42-49.
Dissmeyer, G.E. 1986. Economic impacts of erosion control in forests. In Proceedings
of the southern forestry symposium, November 19-21, 1985, Atlanta, GA., S. Carpenter
(ed.) Oklahoma State University Agricultural Conference Series, pp. 262-287.
c. Urban Areas
COG. 1992 a. A current assessment ofurban best management practices: Techniques for
reducing non-point source pollution in the coastal zone. Metropolitan Washington
Council of Governments. Prepared by T.R. Schueler, P.A. Kumble, and M.A. Heraty.
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[COG Information Center, 777 N. Capital St., N.E. Suite 300, Washington, D.C.,
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Governments. [COG Information Center, 777 N. Capital St., N.E., Suite 300,
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[Distributed by The Terrene Institute, phone: 202/833-3380]
FOLLOW-UP MONITORING (See "The Role of Water Quality Monitoring")
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