TMDL Framework for Action
U.S. Environmental Protection Agency
Office of Science and Technology
Office of Wetlands, Oceans and Watersheds
October 1992
if I 992 if
THE YEAR OF
CLEAN WATER
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TMDL Framework for Action
TMDL
Program
U.S. Environmental Protection Agency
Office of Science and Technology
Office of Wetlands, Oceans and Watersheds
October 1992
* 1 99 2 if
THE YEAR OF
CLEAN WATER
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EXECUTIVE SUMMARY
This document is a joint effort of the U.S. Environmental Protection Agency's Office of
Science and Technology (OST) and Office of Wetlands, Oceans and Watersheds (OWOW). The
purpose of this document is to identify the needs and priorities for execution of the Total Maximum
Daily Load (TMDL) process and the respective responsibilities of each Office. The identified needs
and priorities are multi-year. The Exposure Assessment Branch (EAR) of the Standards and Applied
Science Division (SASD) and the Watershed Branch (WB) of the Assessment and Watershed
Protection Division (AWPD) will work jointly to meet these needs. In some cases EAB and WB
will contribute staff time and contract resources during the same fiscal year. In others EAB and WB
will sequence project responsibilities. For example, WB may initiate work in one year, with EAB
taking up project responsibilities in the second year.
To address the technical issues related to implementation of the TMDL program, a
Workshop on the Water Quality-based Approach for Point and Nonpoint Source Controls was held
in Chicago in June 1991 (USEPA, 1991a). This document responds to the needs outlined by the
Chicago Symposium. In addition, this document incorporates comments provided by the Regional
TMDL Coordinators on earlier drafts of the Framework for Action.
To support the TMDL process a total of 35 projects are identified in this Framework (Table
1). The document presents these needs in two major categories, program needs and research needs.
Program needs are divided into two sub-categories: program and technical guidance and technical
assistance. Research needs are also presented in two sub-categories: model integration and
technology transfer. In the first sub-category of program needs, technical guidance, typical projects
include guidance on targeting and prioritizing water bodies, guidance on TMDL development, and
guidance on monitoring to support TMDL development. In the second sub-category, key technical
assistance projects include a variety of workshops, technical assistance for high priority TMDLs
involving court cases, demonstration projects, SWAT team response, and short term information
exchange on available models and TMDL case studies. In the research needs area, the model
integration section identifies projects to update existing models, develop screening models, test
models for TMDL screening, and evaluate and develop ecological modeling tools. The technology
transfer section outlines a variety of projects to enhance model use through the development of
user's manuals, pre- and post-processors, and innovative training techniques.
A number of quick response projects have already been initiated in FY '92 mostly to address
short term needs. For planning purposes at EPA Headquarters and the Regions, OST and OWOW
have identified projects and personnel needs for FY '93, after considering all regional comments
and suggestions on the Framework. A funding level at 100% of FY'92 is assumed in this planning
exercise to continue implementation of at least a portion of the projects identified in the Framework
for Action. Table 1 summarizes the proposed funding levels by activity for FY '93.
ill
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IV
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PREFACE
Water quality-based point and nonpoint source controls, particularly in the watershed framework,
pose new technical and programmatic challenges which must be faced jointly by a number of
offices within the Office of Water. In many cases other Federal Agencies such as Agriculture,
Interior and Defense as well as States will play key roles in developing and implementing Total
Maximum Daily Loads (TMDL's) in targeted watersheds.
To develop a broad perspective of the technical challenges related to implementing the TMDL
program, the Office of Science and Technology (OST) and the Office of Wetlands, Oceans and
Watersheds (OWOW) jointly hosted a symposium on the water quality-based approach for point
and nonpoint source controls in June 1991. National experts and representatives of EPA
Regions, States and other Federal Agencies participated in this symposium. This Framework
document reflects the needs outlined at the Symposium. The Framework also reflects the
comments and suggestions made by various reviewers.
This document is intended to provide a roadmap for EPA support efforts in areas such as
developing appropriate guidance for national use, providing necessary technical assistance to the
regulated community, developing or updating appropriate watershed and water quality models
for screening and control purposes, and maintaining an effective technology transfer program.
This Framework should help communicate national TMDL program development priorities to
the EPA and State TMDL coordinators. Additionally, we hope that this document will help
EPA collaborate with other Federal agencies.
In order to maximize the TMDL program implementation, the TMDL Framework for Action
identifies short- and long-term needs and priorities. As the needs and priorities change with
time, the Framework will be updated to reflect those changes and the Framework will be used
in defining TMDL objectives and establishing budget priorities.
Suggestions concerning EPA's priorities are welcome and may be sent to: Russell S. Kinerson,
Chief, Exposure Assessment Branch (WH-585) or Bruce Newton, Chief, Watershed Branch
(WH-553), 401 M Street, SW., Washington DC 20460.
y./) .
* ** ( X^.^ /^ >t / J^F f^j ^^^
Tudor T. Davies, Director ^^Ro&h7£^frayland, Director
Office of Science and Technology Office of Wetlands, Oceans and
Watersheds
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VI
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TABLE OF CONTENTS
Page
EXECUTIVE SUMMARY iii
PREFACE v
1. INTRODUCTION : 1
2. REGULATORY BACKGROUND AND PROCEDURAL NEEDS 3
3. TMDL PROGRAM AND RESEARCH NEEDS 5
3.1 Background 5
3.2 Program Needs 5
3.2.1 Program and Technical Guidance Needs 5
3.2.2 Technical Assistance Needs 8
3.3 Research Needs 9
3.3.1 Model Integration and Related Needs 9
3.3.2 Technology Transfer Needs 14
REFERENCES 17
Appendix A: Program Needs A-l
Appendix B: Research Needs B-l
VII
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Vlll
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TMDL Framework for Action
1. INTRODUCTION
This document is a joint effort of the U.S.
Environmental Protection Agency's Office of
Science and Technology (OST) and Office of
Wetlands, Oceans and Watersheds (OWOW).
The purpose of this document is to clarify the
needs and priorities for execution of the TMDL
(total maximum daily load) process and the
respective responsibilities of each Office. The
following framework presents technical support
and guidance needs that must be met to
effectively implement the TMDL process.
These needs are prioritized based on the
available resources of each Office. High
priority needs identified by OST, OWOW or
the Regions that could not be addressed due to
funding constraints were listed to illustrate the
full range of program needs and are expected to
be funded in subsequent years. The specific
roles that OWOW and OST will play in the
development of technical tools and guidance are
identified as well. A common view of TMDL
program needs and goals will help to maximize
the effectiveness of the TMDL program
implementation.
To address the technical issues related to
implementation of the TMDL program, a
Workshop on the Water Quality-based
Approach for Point and Nonpoint Source
Controls was held in Chicago in June 1991
(USEPA, 1991a). The purpose of the
workshop was to explore the state of the
science with national experts and the user
community and determine technical guidance
needs for implementing section 303(d) of the
CWA. A large portion of this framework
document is based on the discussions and
recommendations of workshop participants.
This document also incorporates comments
received from EPA TMDL Regional
Coordinators.
Since the TMDL process is ideally
implemented as a watershed-based approach, all
factors influencing the effective apportionment
of nonpoint source load allocations (LAs) and
point source wasteload allocations (WLAs) need
to be addressed. In addition to broad technical
issues such as guidance, modeling, and
technology transfer in support of the TMDL
process, issues specific to point and nonpoint
sources are discussed. Such issues include, but
are not limited to, combined sewer overflows
(CSOs), stormwater discharges, and nonpoint
source loadings.
The regulatory background and procedural
needs related to TMDLs are discussed in
chapter 2. Chapter 3 presents four types of
program needs: program and technical
guidance, technical assistance, model
integration, and technology transfer. Also
included are two appendices that elaborate on
the issues raised in chapters 2 and 3. Appendix
A details specific projects in the areas of
technical guidance and technical assistance that
will be initiated to meet the program needs
outlined in chapter 3. Appendix B details the
specific modeling and technology transfer
projects that will be initiated. Each project
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TMDL Framework for Action
description in Appendices A and B is presented
as a one-page summary that provides details on
the project, the major issues to be addressed,
project priority, and project implementation
timeframe.
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TMDL Framework for Action
2. REGULATORY BACKGROUND AND PROCEDURAL NEEDS
Section 303(d) of the Clean Water Act
(CWA) established the TMDL process to
provide for more stringent water quality-based
controls when technology-based controls are
inadequate to achieve State Water Quality
Standards (WQSs). The water quality-based
approach encompasses the TMDL process,
which contains five steps: (1) identification of
water quality-limited waters and, subsequently,
waters that require TMDLs; (2) priority ranking
and targeting of those waters; (3) TMDL
development; (4) implementation of pollution
control actions; and (5) monitoring and
assessment of control actions. Step 5 provides
for continuous evaluation and improvement of
the TMDL and any pollution control actions.
A TMDL is the sum of the individual
wasteload allocations for point sources, the load
allocations for nonpoint sources and natural
background pollutant levels, and a margin of
safety (MOS) that reflects the degree of
uncertainty involved in the calculations (TMDL
= EWLA + ELA + MOS). Historically,
however, implementation of the 303(d) process
has focused on point source wasteload
allocations; nonpoint sources were not
considered in detail, largely because nonpoint
sources are more difficult to quantify and
control.
It is clear now, however, that we must go
beyond point source controls to effectively
attain State WQSs. All sources of pollution
must be considered, including nonchemical
stressors such as habitat alteration and
hydromodification. Therefore, it is necessary
to look beyond the traditional chemical
evaluation of water quality and incorporate
evaluations of the physical and biological
components of aquatic ecosystems.
EPA has recently issued a guidance document
on the water quality-based approach and the
TMDL process (USEPA, 1991b). The
document outlines the TMDL process and the
respective responsibilities of EPA and the
States. The document also stresses the
importance of addressing all point and nonpoint
factors that may influence the allocation of
WLAs and LAs. To evaluate the effectiveness
of the WLAs and LAs, and to ensure that all
significant factors have been identified, the
guidance document recommends the use of a
"phased approach," defined as a TMDL that
includes monitoring and re-assessment
schedules designed to evaluate the TMDL's
success in meeting WQSs.
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Table 1: Siounary of Proposed 1993 TMDL Budget forEAB/OCT and WB/OWOW1
'This lablc
• These pr
Item
1
1
2
3
4-8
9
Description
Program and Ttehnleal Guidance
Guidance on Ttrgeung and Prioritizing Wafer Bodies*
Guidance on TMDL Development
Guidance on Monitoring to Support TMDLS
Supplementary Technical Guidance (Wet Weather and Clean
Sediment Criteria) •
Comprehensive Guidance Document for Variable Loading*
OST
(Sl.OOO)
FY93
100
100
OWOW
(Sl.OOO)
FY93
Tout
50
100
50
100
200
Ttehnleal Aataanct
10
11
12
13
14-18
19
20
21
22
23
24
25
26
27
28
29
Workahopi*
Woriuhopt on Contaminated Sedimenu Criteria
Direct Support to TMDL Related Court Caiei*
TMDL SWAT Team*
Information Exchange (Case Studies/Model Review/Mini-gram)*
Modtl InUgraOon
Model Integration (CORMDC/Screening Model Development)*
Ecological Modela/Restoration
Data Acceia Tools*
Design Storm Event
Biological Criteria
BMP Effectiveness**
Model Revision
Adaptation of Models to CIS Platforms
Sediment Quality Models
TMDL Model Testing *
Guidance on Default Parameter Selection
65
'
75
75
65
225
20
SO
100
215
50
150
20
50
115
75
175
280
275
150
40
50
Technology Tnuuftr
30
31
32
33
34
35
summarizes E
ejects hive bet
Conduct Training and Workshops
Innovative Delivery Systems
User's Manuals
Pre- and Post-Processor Development
Technical Aaaictance
Joint Federal Interagency Clearinghouse
AB's end WB's proposed contract funding for TMDL support only Oi
n initiated in FY92 •• This project has been initiated in FY92 by the
65
100
65
100
iher branch activities are not included
NPS branch of AWPD and funding continues
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TMDL Framework for Action
3. TMDL PROGRAM AND RESEARCH NEEDS
3.1 Background
The TMDL process is implemented using the
watershed-based approach. Effective allocation
of WLAs and LAs relies on the ability to
identify, gather, and integrate data that reflect
the relationships among the physical, chemical,
and biological characteristics of a watershed,
and the contribution of point and nonpoint
pollution sources. Water quality-based
management must depend heavily on technology
such as monitoring to gather data and various
levels of computer models to simulate the water
system at various levels of complexity. Over
time technological advances in the area of
remote sensing will be used more frequently in
the data collection process. Preliminary
assessments may often rely on available data
and simple screening models. The phased
approach will allow for incremental fine-tuning
of TMDLs as additional data are collected and
more detailed analyses are performed.
Listed below are the needs that will have to
be addressed to move the TMDL Program
forward. These needs are presented in priority
order according to the Office responsible for
leading the programs. General guidance needs
and technical assistance projects are to be led
by OST and OWOW. Research, model
development, and related technology transfer
projects are to be implemented by OST and
OWOW with support and assistance from the
Office of Research and Development (ORD)
when necessary.
In order to address immediate Regional and
State needs for assistance in TMDL
development, a number of short term projects
have already been initiated in FY '92. After
considering all Regional comments and
suggestions on the Framework, EPA Head-
quarters and the Regions, OST, and OWOW
have also identified projects and personnel
needs for FY '93. A funding level at 100% of
FY'92 is assumed in this planning exercise to
continue implementation of at least a portion of
the projects identified in the Framework for
Action. Table 1 summarizes the proposed
funding levels by activity for FY '93.
3.2 Program Needs
3.2.1 Program and Technical Guidance
Needs
This section addresses guidance needs for
implementation of the five-step TMDL
development process. Participants at the
Chicago workshop recommended the following
TMDL-related technical guidance (USEPA,
1991a). Those projects having funding in FY
'92 and/or FY '93 are marked ($).
• Guidance on targeting and prioritizing
water bodies: OWOW (AWPD) has
already begun to develop a handbook to
help States target and prioritize watersheds.
The handbook describes the various
"geotargeting" techniques that have been
used to target and prioritize watersheds.
The handbook focuses on techniques that
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TMDL Framework for Action
are appropriate for TMDL applications.
Targeting techniques include the following
major categories: weighting factor, decision
tree, data overlay (GIS), and programmatic
approaches. The development of this
handbook has high priority since targeting
and prioritizing is a crucial first step in
initiating the TMDL process. [Item #1,
OWOW] ($)
Guidance on TMDL development: To
build on the programmatic requirements of
the water quality-based approach, as
outlined in the existing guidance document,
a more technically based guidance document
is needed. This document will build on
existing EPA publications. The guidance
document should include a description of
various models, procedures to select
watershed and water quality simulation
models, the tie between modeling
applications and ambient water quality
standards, use of models and analytical
techniques to develop a fully articulated
TMDL/WLA/LA for both point and
nonpoint sources, and TMDL case study
examples. A number of projects have
already been initiated to provide preliminary
technical assistance including: a
compendium of available models for
watershed-based screening, detailed TMDL
case study examples for distribution to the
States and Regions, and TMDL minigrants
for Regions, States, and local water quality
agencies (see also Items #15 and #16). The
results of these preliminary projects can
eventually be incorporated in the guidance
document. [Item #2, OST and OWOW\ ($)
Guidance on monitoring to support
development of TMDLs: This document
should describe the data needs and
recommended monitoring techniques for the
development of TMDLs. It should also
include the various chemical and biological
methods that can be used to generate site-
specific data for use in particular models.
Special monitoring needs in the area of
habitat limitation, NFS, clean sediment, and
high flow TMDLs, and TMDL effectiveness
should be addressed as well. Multiple
documents may be required to address the
variety of waters that are monitored (e.g.,
streams, lakes, reservoirs and estuaries).
[Item #3, OST and OWOW]
Supplementary technical guidance: Since
TMDLs are implemented on the watershed
level, a wide variety of pollutant sources
need to be considered. More specific
technical guidance is needed in the areas
listed below. These should be developed in
coordination with and in support of the
guidance mentioned above. The
development of guidance in the areas of
CSO/stormwater discharges, contaminated
and clean sediments, whole effluent
toxicity, and biological criteria, will assist
in the implementation of the TMDL
process.
CSOs/stormwater discharges: Directed
studies, assessment, and guidance are
needed to evaluate CSOs and storm water
discharges as part of watershed processes.
The variable nature of these rainfall-
driven discharges requires the
development of new assessment tools.
Effective control of CSO and stormwater
discharges may require the development
of wet weather criteria for some
pollutants. Crosscutting CSO and
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TMDL Framework for Action
stormwater discharge issues include
modeling, design storm events, and BMP
effectiveness. [Item #4. OST\ ($)
Contaminated sediments: Contaminated
sediments have the potential to cause
toxicity, bioaccumulation, and other water
quality impacts even when the overlying
water column is deemed to be in
compliance with existing water quality
criteria. In conjunction with EPA's
efforts to establish sediment criteria,
guidance that clearly outlines the influence
of contaminated sediments on water
quality is needed so that Regions and
States can make informed decisions.
These impacts must then be considered in
terms of the TMDL process. [Item #5,
057] ($)
Clean sediment criteria: Clean
sediments can have adverse impacts on
aquatic ecosystems. Research studies are
needed to determine the ecological and
biological endpoints related to sediment
embeddedness. More particularly criteria
need to be developed to assess impacts of
sediment embeddedness on cold as well as
warm water fisheries. Criteria will need
to be developed based on the results of
research. Tools will be needed to
estimate the range of impacts and
determine the effects of land use activities
on sedimentation. Case studies can be
used to demonstrate that criteria and
estimation procedures are effective. [Item
#6, OST and OWOW] ($)
Whole effluent toxicity (WET): The
impacts of toxic chemicals on water
quality and the biological components of
an aquatic ecosystem need to be
determined, particularly the combined
impacts of multiple toxic chemicals from
industrial, urban, and agricultural sources.
The use of whole effluent toxicity within
the TMDL process needs to be evaluated,
and guidance provided to the Regions and
States. [Item #7, 057] ($)
Biological criteria: States have been
instructed to incorporate narrative
biological criteria into existing water
quality standards. Guidance that stresses
the value of such criteria as an aid to
existing methods is necessary, as well as
guidance that aids States in the design,
selection, and implementation of such
criteria. [Item #8, OST and OWOW]
Development of a Comprehensive
Guidance Document for Assessing
Variable Loadings: The TSD currently
does not adequately address the variable
loadings from CSOs, stormwater, and
nonpoint sources. A new comprehensive
document should be developed which
addresses variable loadings in relation to the
standards-to-permits process. This new
document will encompass the TMDL
approach. The new document will include
the basic elements of TMDL
implementation for conventional as well as
nonconventional pollutants, toxics, and
clean sediments. The new document will
also address models for nonpoint source
assessment and load estimation,
development of LAs for nonpoint sources,
and integration of point and nonpoint source
models. [Item #9, OST and OWOW]
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TMDL Framework for Action
3.2.2 Technical Assistance Needs
This section addresses technical assistance
needed to implement and facilitate the five-step
TMDL development process. This assistance
falls into three general categories: (1) training
and workshops, (2) direct support services to
Regions and States, and (3) information
exchange activities.
• Workshops: OST- and OWOW-led
workshops are needed to provide guidance
to the Regions and States on the technical
skills required for the development of
TMDLs. Workshops will include
discussion of the regulatory aspects,
monitoring, modeling, data management,
and interpretation techniques required for
the development of TMDLs. Technical
workshops may need to be presented at
more than one level (i.e., intermediate and
advanced) and include additional technical
skills such as statistical analysis for model
verification and calibration, sampling
design, and data analysis. Local
presentations would allow the discussion to
be tailored to meet Region-specific needs.
At least five workshops per year are
recommended so that each Region will have
at least one workshop every two years.
Because of funding limitations, it may be
advantageous to offer workshops at a
centralized facility and require participants
to pay a nominal fee to defray expenses. To
provide on-going assistance a TMDL
modeling user's group may be
advantageous. [Item #10, OSTandOWOW]
($)
Workshops on the implementation of
contaminated sediment criteria:
Workshops will be conducted for Regions
and various Federal and State agency
personnel to help implement contaminated
sediment criteria through the State WQS
process and to bring contaminated sediment
within the TMDL process. Workshops
would also, serve to identify modeling and
other technical needs concerning
contaminated sediments. (EPA is currently
working toward developing criteria for
contaminated sediments.) [Item #11, OST\
Direct support for high-priority TMDL-
related court cases: OST and OWOW will
provide expert support and consulting
services for selected TMDL-related court
cases. [Item #12, OST and OWOW] ($)
TMDL SWAT team: The surface water
assessment technical (SWAT) team consists
of experts who are familiar with the
technical aspects of TMDL development.
The SWAT team will provide short-term
expertise to EPA Regions, States, and local
governments that are developing targeting
programs and TMDLs (with special
emphasis on nonpoint sources and
watershed scale projects) under the 303(d)
program. The program provides immediate
expert assistance to TMDLs which are
under development. [Item #13, OWOW] ($)
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TMDL Framework for Action
Information exchange: Access to
information on other case studies, court
cases, related modeling studies, and
available models will assist Regions and
States in implementing TMDLs. This
service will be provided by developing a
clearinghouse, data bases, annotated
bibliographies, and review documents.
Rapid dissemination of this information will
assist Regions and States in the early stages
of TMDL development. TMDL mini-grants
will be made available for Regions, States,
and local water quality agencies for TMDL
development. Information on TMDL
development will be collated, standardized,
and disseminated.
Coordination with Regions and States
on the TMDL process. OST and
OWOW will work with the Regions and
States on improving technologies and
approaches to support the TMDL process.
Innovative technologies such as remote
sensing, GIS, IBI, RBP, etc... will be
made available to the user community.
[Item #14, OSTandOWOW\
Case study examples. Case studies are
proposed for inclusion in TMDL guidance
(see Item #2). There is an immediate
need for technical assistance to the
Regions and States. By means of
information exchange, case study
examples would be provided to the
Regions and States on an accelerated
basis. [Item #15, OST and OWOW] ($)
Model reviews. Model descriptions and
testing are proposed for inclusion in a
comprehensive TMDL Technical
Guidance document (See Item #2). An
3.3
on-going OWOW project is reviewing
available models for TMDL development.
This compendium identifies a range of
methods from very simple to detailed
which can be applied for TMDL
screening, targeting and development.
The compendium will be provided to the
Regions and States on an accelerated
basis. [Item #16, OWOW] ($)
Electronic bulletin board: A TMDL
special interest group (SIG) is in the
process of being established as a part of
NFS Bulletin Board System (BBS). [Item
#17, OWOW and OST] ($)
Legal support: Information on current
and/or pending lawsuits will be provided
to Regions and States on a continuing
basis. [Item #18, OWOW] ($)
Research Needs
3.3.1 Model Integration and Related
Needs
A wide variety of models can be used to
identify impaired waters, prioritize such waters,
and develop TMDLs. Simple screening models
are necessary to identify water quality-impaired
or threatened waters that require TMDLs.
More complex models are needed for diagnostic
purposes in order to target and prioritize point
and nonpoint source activities requiring
pollution controls. Technically defensible
models are needed to develop TMDL
allocations.
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TMDL Framework for Action
Models are available in a variety of forms.
Watershed models are used to estimate
loadings from both point sources and nonpoint
sources for urban and rural land use activities,
and are particularly useful in the pollutant
allocation phase of the TMDL process. Some
watershed models can be used to simulate the
loadings produced by periodic combined sewer
overflows and storm water discharges. Mixing
zone models evaluate localized impacts from
point sources and nonpoint sources on water
quality. These are typically steady-state models
used primarily for point source permitting.
Water quality models are available to
determine the impacts of loadings on receiving
waters using either dynamic or steady-state
techniques. Ecological models address
ecosystem response to particular land use
activities. The four general model types are
described in greater detail below.
Watershed Models; EPA currently supports
and distributes two detailed models: the
Hydrologic Simulation Program - FORTRAN
(HSPF) for urban and rural mixed land use
activities and the Storm Water Management
Model (SWMM) for urban land use activities.
Detailed model documentation is available;
however, no simplified guidance on model
application is available. EPA also provides
some limited support for these models, but such
support needs to be expanded if these models
are to used on a wider scale. The U.S.
Department of Agriculture Soil Conservation
Service (USDA-SCS) has developed six
relatively simple and user-friendly models that
may be useful for TMDL development in
agricultural areas (e.g., Agricultural Non-Point
Source Pollution Model (AGNPS), Simulator
for Water Resources in Rural Basin-Water
Quality model (SWRRBWQ), Erosion-
Productivity Impact Calculator (EPIC),
Groundwater Loading Effects of Agricultural
Management Systems (GLEAMS), Chemicals,
Runoff, Erosion from Agricultural Management
Systems (CREAMS), and Nitrate Leaching and
Economic Analysis Package (NLEAP)).
GLEAMS, CREAMS, EPIC, and NLEAP are
field scale models and therefore have limitations
with regard to the watershed-based TMDL
process. The SWRRBWQ model can be
applied on a watershed basis for continuous
simulation, but additional development of model
components for nutrient and pesticide transport
is under way. The AGNPS model is
watershed-based but is currently limited by
application to design storms only. USDA is
currently upgrading AGNPS to include
continuous simulation as well.
Some watershed models have the capability to
assess pollutant loadings due to CSOs. The
EPA-distributed SWMM model was originally
developed for CSO modeling (WPCF, 1989).
It has the capacity to route flows and pollutants
through complex sewer systems and to evaluate
the impact of storage and special structures.
The HSPF model can also be used for CSO
assessment but has a more limited capacity for
detailed flow and pollutant routing. Other
notable models with CSO capabilities include
STORM (COE), DR3M-QUAL (USGS), and
ILLUDAS (Illinois State Water Survey)
(WPCF, 1989).
Although hydrologic and hydraulic character-
istics have been successfully modeled, quality
modeling is generally less reliable, because of
the complexity of pollutant transport and the
number of parameters that must be estimated
for successful calibration (Nix et al., 1991).
10
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TMDL Framework for Action
Screening models: A number of simpler
screening models are commonly used by the
Regions, States, local governments, research
institutions, and the private sector for watershed
assessment, targeting and TMDL development.
No simple watershed screening models are
currently distributed or supported by EPA.
Mixing zone models: Five EPA near-field
mixing zone models were developed primarily
in the late 1970s to meet 301(h) needs. They
are UPLUME, UMERGE, UOUTPLM,
UDKHDEN and ULINE. To implement
existing mixing zone policies at the State and
Federal levels, the Environmental Research
Laboratory at Athens and the Office of Water
jointly funded development of the CORMIX
mixing zone models. CORMIX 1 is designed
to address submerged single port discharges;
CORMIX 2 is designed to address submerged
multiport discharges; and CORMIX 3 is
designed to address surface discharges.
CORMIX 1 and 2 are currently available, and
CORMIX 3 is in the last stage of its
development under a two-year cooperative
agreement with Cornell University. The first
test version of CORMIX 3 has been distributed
for comments ahead of schedule. OWOW
provided $60K for the first year of the two-year
agreement. Many features of these models are
similar. For this reason, Environmental
Research Laboratory-Narragansett (ERL-N), at
the Newport, Oregon field office, is planning
through FY 92 and 93 to consolidate the five
EPA models into two models, and CORMIX 1,
2, and 3 into one CORMIX model. These
models are provided to the user community
with detailed documentation manuals, but no
easy to follow user's manuals or tutorial
diskettes. ERL-N has initiated plans to address
these problems.
Based on recent arrangements, all near-field
models are now distributed through ERL-
Athens, and all model development,
maintenance and technical assistance is
accomplished through ERL-N.
Water quality models: Some important water
quality models supported by EPA include
DYNTOX, EXAMS, MINTEQ (metals
speciation), QUAL2E, WASP4, SMP and
SMPTOX. These models are used to simulate
water quality in receiving waters (e.g., lakes,
rivers, and estuaries) using fate and transport
processes. These models are also difficult to
apply because of the lack of simple user's
manuals.
Ecological models: EPA does not currently
support and/or distribute ecological models for
assessing either aquatic or terrestrial habitats.
Several simple and reliable ecological models
that are available in the private sector may be
helpful in implementing ecocriteria and
promoting habitat restoration. Most of these
ecological response models are not yet at the
stage of predicting "true" ecological response
(i.e., changes in production, biomass,
recruitment, etc.), but offer stream managers a
scale by which to compare relative magnitudes
of improvement or success of restoration
efforts.
During the TMDL Workshop, the Watershed
Modeling Workgroup discussed the application
of models for the development of TMDLs
(USEPA, 199la). Major concerns were raised
regarding the accuracy and reliability of models
for TMDL development, the limited data
available for model application, and the
multiple Federal agencies supporting the
models. A number of short- and long-term
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TMDL Framework for Action
modeling needs were determined by the
Workgroup. The project list below responds to
many of the needs identified by the Workgroup.
The TMDL Regional Coordinators identified
the development, support and testing of
screening models as a major research need. An
emphasis on screening models and facilitating
and simplifying the use of existing models is
also reflected in the items below. Other
concerns addressed below are model input
requirements, model support and revision, and
model testing.
Short-term Needs
• Model integration: Models are not
currently designed to be used in a combined
fashion. The watershed-based approach will
often require that multiple models be used
to evaluate a watershed. Although models
are available to address most components of
watershed-based analysis, each model is
designed for a specific need. The use of
multiple models for a watershed-based
analysis is complicated by the various time
scales, data formats, and model
assumptions. For example, a daily
simulation from a watershed model may
need to be meshed with a water quality
simulation for a receiving water. To
facilitate this process pre- and post-
processors need to be developed to link
model input and output. For example,
output from SWMM (a watershed model)
could be reformatted to provide input to
WASP4 (a water quality model).
The CORMIX mixing zone model is
currently distributed as three models.
Future work will combine the three models
into one. A single user's manual and
documentation will be prepared for the new
combined model.
Screening models are needed for the initial
targeting phase of the TMDL development
process. These models, although limited in
accuracy, require minimal data collection
and can be used effectively in the
preliminary stages of TMDL development.
A review of models has been initiated in
Item #16. Simple screening level models
are available; however, many are site-
specific, lack detailed documentation, and
are not widely distributed. In this task a
screening methodology will be developed,
building on available models. Components
of the screening model may include
enhanced capabilities for data retrieval from
EPA mainframe resources, a user-friendly
interface, output statistics and graphics, and
a detailed user's manual. The development
of a screening model has been initiated in
cooperation with Region IV as part of the
screening model compendium. [Item #19,
OWOW and 057] ($)
Ecological models: Habitat and ecological
restoration techniques are currently being
explored and developed. Simple models
that can predict response(s) of an ecosystem
to a particular impact (e.g., restoration
activity) need to be developed, evaluated,
and validated. [Item #20, OWOW and OST\
($)
Data access tools: Most models used to
evaluate nonpoint source pollution have data
requirements that include region- or site-
specific information on rainfall, soil type,
hydrology (including stream flow),
topography, and land use. Data-access
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TMDL Framework for Action
tools (software packages) are needed so that
data from national data bases are readily
available and compatible for use with such
models. A new methodology is currently
under development to link mainframe data
bases with a regional evaluation procedure
and PC-based screening model (Region
IV/OWOW). As our data bases improve,
data access tools will be upgraded as well.
Ongoing mainframe data base improvements
which may be beneficial to the TMDL
program include indexing of RF3 to
STORET and PCS. Future enhancements
may include streamflow and reservoir
information associated with RF3. [Item
#21, OWOW and OST\ ($)
Design storm event: Wet weather
conditions are critical in determining the
extent and impact of nonpoint source
pollutants. While water quality assessments
for point sources are often based on critical
low-flow conditions, nonpoint source
assessments must take high-flow conditions
into account. The frequency of exceedence
of water quality criteria is directly related to
critical conditions for rainfall-driven
impacts including size of event, moisture
condition, time since previous storm event,
and land use activities. For variable,
rainfall driven impacts the development of
wet weather criteria may be appropriate. If
an appropriate design storm for assessing
wet weather impacts can be selected, the
initial model analyses could be more easily
performed. A team of national experts
should be convened to identify a
methodology for selecting a design storm
for wet weather loading estimates. A
prototype design storm selection
methodology should then be tested under a
variety of conditions using case studies.
[Item #22, OWOW and OST\
Long-term Needs
• Biological criteria: The Office of Water is
currently working on an initiative to
develop biological criteria for aquatic
ecosystems. While the use of biological
criteria for. stream evaluations has already
been initiated in ecological assessment
programs, biological criteria will allow
identification of ecosystems under stress,
the sources and causes of the stress, and the
ecosystems at the greatest potential for risk.
One goal of the research is to be able to
directly link physical and biological stress
with ecosystem dysfunction, [hem #23.
OST\
• BMP effectiveness: The effectiveness of
best management practices (BMPs) or other
control measures required by a TMDL can
be determined only through regular moni-
toring and assessment activities.
Participants at the Chicago workshop
identified the need for a compendium of
BMPs (including follow-up monitoring data)
and their measured effectiveness. The NPS
Branch is working on this topic through the
Coastal Zone Management Act (CZMA)
efforts. Future work will need to focus on
development and testing of models for BMP
assessment. [Item #24, 057] ($)
• Model Revision: It is necessary to identify
areas where models should be revised (e.g.,
air/water, sediment/water, and
ground/surface water interfaces) because
many of the currently supported EPA and
USD A models calculate runoff, erosion,
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TMDL Framework for Action
nutrient loading, and chemical transport
using older techniques. Existing models
would be selectively updated, thereby
enhancing model capabilities and improving
accuracy. [Item #25, OST\
Adaptation of models to GIS platforms:
CIS is a tool that can be used to integrate
basinwide data for water quality
assessments. GIS can overlay information
on soils, land use, wetlands, topography,
and critical areas. It can be used to
evaluate watersheds for targeting purposes
and develop model inputs. GIS
implementation requires a significant level
of effort for initial digitization of data. As
more and more data become available in
GIS format, this technology will have wider
applicability. Future work on models
should acknowledge the need for GIS
interfaces. To improve the portability of
information into models and results from
one model to another, EPA-supported
models should be updated in the future to
interface with a common (GIS)
environment. [Item #26, OWOW and OST\
Sediment quality models: Based on the
results of the workshop under Item #11, a
research plan should be developed and
implemented to address sediment quantity
and quality models for application in lake,
river, and estuarine situations to assess
impacts of clean sediment deposition on
cold and warm water fisheries. [Item #27,
OWOW and OST\
TMDL model testing: Site-specific testing
of a selected number of models should be
performed. Models applied to the TMDL
process will need to be verified to ensure
user confidence in model applications. A
number of possible sites for model testing
could be identified with a variety of
problems (e.g., NPS, PS, groundwater...)
and located in various regions of the
country. Model testing will be performed
in cooperation with the Regions and States
to evaluate site specific issues. Additional
testing should be performed in the
West/Southwest. Model testing would be
used to develop step-by-step guidance on
model applications for inclusion in the
TMDL Technical Guidance document (see
also Item #2). [Item #28, OWOW and OST\
($)
Guidance on default parameter selection:
Currently models such as HSPF and
SWMM have limited guidance on input
values, particularly in the areas of pollutant
accumulation, washoff, and transport.
Demonstration projects, model testing, and
pilot studies should be used to determine a
range of appropriate input parameters that
can be used for planning-level assessments
or as initial values for calibration.
Parameters will be described as a range of
possible input values based on documented
research. A few carefully selected OST-led
demonstration projects could be used to
develop the appropriate inputs. [Item #29,
OST\
3.3.2 Technology Transfer Needs
Effective transfer of TMDL technologies to
the public depends on (1) improving the user-
friendliness of tools and technologies; (2)
conducting training, seminars, and workshops;
and (3) providing project-specific technical
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TMDL Framework for Action
assistance on requests from individual users.
Each topic is briefly described below.
• Training and workshops: EPA currently
conducts (via ORD laboratories and
contractor support) a limited number of
workshops each year oriented toward ORD-
supported models. To support TMDL
technology transfer, these workshops should
be enhanced with improved visual aids and
sample applications. With the need for
watershed-based modeling, there will be an
increased demand for training that includes
nonpoint source modeling. As a result, the
technology transfer program will require
additional expert support services. [Item
#30, OWOW and OST\
• Innovative delivery systems for
technology transfer: Hands-on training
and telephone assistance are often needed to
run the models that are distributed through
EPA. Although EPA conducts a number of
workshops at ORD and regional sites, the
number is limited. Model training could
reach even more potential users with
videotaped presentations of workshops,
which could be provided to a Region, a
State, a local government, a university, or
a private consultant on an as-needed basis.
Demonstration diskettes and computer based
training (CBT), using modem animation
techniques, could be used as well. These
types of technology transfer techniques
could reach a wider audience than the
current workshop format. [Item #31, 057]
• User's manuals: Currently, no simple
user's manuals are available for the models
that have been developed, supported, and
distributed by EPA. Instead, ORD
distributes models with a complete
documentation manual that is often rather
imposing. Knowledge of all of the
assumptions that were involved in model
development are necessary for many model
applications. Even with such knowledge,
hands-on training and telephone assistance
are often needed to run the model. A
simple user's manual with several pertinent
examples . would greatly facilitate
widespread use of EPA-distributed models
by States and local governments to develop
TMDLs. User's manuals will include
teaching aides such as a tutorial which takes
the user through a sample application
enhanced by graphics and animation. [Item
#32, 057]
• Pre- and post-processor development:
The development of user-friendly interfaces
for computer models can greatly enhance
the use of models for TMDL development.
Typically the preparation of data, data
input, and data interpretation for a model
are very time consuming. In addition, input
and output are in a different format for each
model. In this activity pre- and post-
processors would be developed for each
supported model using modern PC
technology for better graphics and
animation. The pre-processor would
provide menus for data entry, help screens
for assistance in selecting input values, and
a uniform format for all models. The post-
processor would facilitate interpretation of
model results and information transfer
between models (see also Item #19). [Item
#33, 057] ($)
• Technical assistance: Demands on EPA's
technical assistance program are increasing
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TMDL Framework for Action
and will continue to increase as more
groups and individuals use models that are
distributed by EPA. In addition to EPA
staff, cooperative agreements are established
with other water quality modelers whose
expertise is not shared by those within
EPA. To ensure that user queries are
answered completely and efficiently,
guidance, model clearinghouses and expert
support services must be expanded. [Item
#34. OWOWand 057]. ($)
Joint Federal interagency model
clearinghouse: To ensure a consistent
approach to watershed modeling and
interpretation of modeling results, it would be
most helpful to coordinate EPA's modeling
activities with those of other Federal agencies
(e.g., Army Corps of Engineers, US
Department of Agriculture, USDA/Forest
Service, US Geological Survey, Bureau of
Land Management, Bureau of Reclamation).
This would eliminate duplication of effort,
provide comprehensive support for Federal
models, and facilitate technology transfer
between the agencies, as well as with the
public. [Item #35, OWOW and OST\
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TMDL Framework for Action
REFERENCES
Nix, S.J., P.E. Moffa, and D.P. Davis. 1991.
The practice of combined sewer system
modeling, Water Resource Bulletin 27(2): 189-
197.
USEPA. 199la. Workshop on the water
quality-based approach for point source and
nonpoint source controls, U.S. Environmental
Protection Agency. EPA 503/9-91-001.
USEPA. 19915. Guidance for water quality-
based decisions: The TMDL process. U.S.
Environmental Protection Agency. EPA 440/4-
91-001.
WPCF. 1989. Combined sewer overflow
abatement: Manual for practice. Water
Pollution Control Federation. Doc. No. FD-
117.
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TMDL Homework for Action
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TMDL Framework for Action
APPENDIX A
PROGRAM NEEDS
PART I - TECHNICAL GUIDANCE NEEDS
PART D - TECHNICAL ASSISTANCE NEEDS
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TMDL Framework for Action
APPENDIX A: PARTI
Item #1: Guidance on geographic targeting and prioritizing water bodies
OVERVIEW:
OWOW (AWPD) has drafted a handbook to help States target and prioritize watersheds. The handbook
describes the various geographic targeting techniques that have been used to target and prioritize watersheds.
It focuses on techniques that are appropriate for TMDL applications. Targeting techniques include the
following major categories: weighting factor, decision tree, data overlay (CIS), and programmatic
approaches. The most commonly used technique is a combination of weighting factor and programmatic
approaches. Additional topics discussed are data integration for targeting and a simple loading rate model
case study.
ISSUES:
• Limited resources require that Regions/States target and prioritize TMDL development and
implementation efforts to .key watersheds.
• Guidance on screening and targeting methods would provide valuable assistance to the Regions/States and
facilitate the implementation process.
COMPLETED:
3 years
A-l
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TMDL Framework for Action APPENDIX A: PARTI
82: Guidance on TMDL Development
OVERVIEW:
To build on the programmatic requirements of the water quality-based approach as outlined in the existing
guidance document, a more technically based guidance document is needed. The document should illustrate
the technical steps required to develop a variety of TMDLs. This document should include targeting and
prioritization techniques, descriptions of various models, procedures to select watershed and water quality
simulation models, the tie between modeling applications and ambient water quality standards, use of models
and analytical techniques to develop a fully articulated TMDL/WLA/LA for both point and nonpoint sources,
and TMDL case study examples. Models would be tested and application procedures clearly outlined to
facilitate application by the Regions/States. Data requirements for model input including monitoring
requirements would be clearly outlined.
ISSUES:
• Programmatic guidance on TMDL development was described in the TMDL guidance document.
• Implementation of TMDL development would be assisted by technical guidance. Discussion at the
Chicago workshop clearly demonstrated the need for additional technical guidance.
• Technical guidance is needed in the area of model selection and application. The guidance should be
specific to the needs of the TMDL process.
COMPLETED:
3 years
A-2
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TMDL Framework for Action APPENDIX A: PARTI
Item #3: Guidance on monitoring to support development of TMDLs
OVERVIEW:
This document should describe a variety of monitoring techniques that can be used in the development of
TMDLs. It should also include the various chemical and biological methods that can be used to generate site-
specific data that can be used for particular models. Different techniques may be needed at each phase in
the development of a TMDL. Initial monitoring may be used for screening and targeting. Additional
monitoring may be needed for watershed assessment and habitat assessment, and more detailed monitoring
may be required to develop the TMDL. The document may include monitoring procedures to assess the
effectiveness of TMDLs. Because of the high cost of monitoring, the guidance manual will be helpful to
target resources and maximize results from monitoring programs.
Monitoring is needed in river, lake, and estuarine environments. Multiple guidance documents may be
needed to address the unique needs of each type of water body.
ISSUES:
A wide range of monitoring techniques may be needed to address the needs of TMDL development in
keeping with the phased approach.
Biological monitoring may in some cases be an appropriate surrogate or addition to chemical monitoring.
COMPLETED:
5 years
A-3
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TMDL Framework for Action APPENDIX A: PARTI
Items #4-8: Supplementary Technical Guidance
OVERVIEW:
More specific technical guidance should be considered in the areas listed below. Such guidance should be
developed in coordination with and in support of guidance described in Item #2.
CSOs/stormwater discharges: Assessment, directed studies, and guidance are needed to evaluate CSOs and
stormwater discharges as part of watershed processes. The variable nature of these rainfall-driven discharges
requires the development of new assessment tools. Effective control of CSO and stormwater discharges may
require the development of wet weather criteria. Crosscutting CSO and stormwater discharge issues include
modeling, design storm events, and BMP effectiveness.
Contaminated sediments: Contaminated sediments have the potential to cause toxicity, bioaccumulation,
and other water quality impacts even when the surrounding water column was deemed to be in compliance
with existing water quality criteria. In conjunction with EPA's efforts to establish sediment criteria, guidance
that clearly outlines the influence of contaminated sediments on water quality is needed so that Regions and
States can make informed decisions. These impacts must then be considered in terms of the TMDL process.
Clean sediment criteria: Clean sediments can have adverse impacts on aquatic ecosystems. Research
studies are needed to determine the ecological and biological endpoints due to sediment embeddedness. More
particularly criteria need to be developed to assess impacts of sediment embeddedness on cold and warm
water fisheries. Criteria will need to be developed based on the results of research. Tools will be needed
to estimate the range of impacts and determine the effects of land use activities on sedimentation. Case
studies can be used to demonstrate that criteria and estimation procedures are effective.
Whole effluent toxicity (WET): The impacts of toxic chemicals on water quality and the biological
components of an aquatic ecosystem need to be determined, particularly the combined impacts of multiple
toxic chemicals from industrial, urban, and agricultural sources. The use of whole effluent toxicity within
the TMDL process needs to be evaluated, and then guidance must be provided to the Regions and States.
Biological criteria: States have been instructed to incorporate narrative biological criteria into existing water
quality standards. Guidance that stresses the value of such criteria as an aid to existing methods is necessary,
as well as guidance that aids States in the design, selection, and implementation of such criteria.
ISSUES:
• Since the TMDL process is ideally implemented as a watershed-based approach, a wide variety of issues
need to be addressed in quantifying and analyzing the pollutant sources. Documents that can potentially
support the process need to be developed and integrated into the TMDL guidance.
COMPLETED: 5 years
A-4
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TMDL Framework for Action APPENDIX A: PARTI
#9: Development of a Comprehensive Guidance Document for Assessing Variable
Loadings
OVERVIEW:
The TSD currently does not adequately address the nonpoint source aspects of the TMDL program. A new
comprehensive document should be developed which addresses variable loadings in relation to the standards-
to-permits process. This new document will encompass the TMDL approach. The new document will
include the basic elements of TMDL implementation for conventional as well as nonconventional pollutants,
including toxics. Since clean sediments cause considerable water quality impairments, clean sediments will
be included in the comprehensive guidance document. The new document will also address models for
nonpoint source assessment and load estimation, development of LAs for nonpoint sources, and integration
of point and nonpoint source models. Steady-state approaches are often not adequate for addressing these
types of impacts. The new document would incorporate dynamic methodologies for handling a wider range
of nonpoint and point (CSOs and stormwater) source impacts.
ISSUES:
• TMDLs must incorporate point and nonpoint sources into a watershed-based approach.
• The recent revision of the TSD focuses on steady-state impacts, not on the dynamic impacts typical of
nonpoint sources, stormwater, and CSO discharges.
• The new document will be needed to incorporate the TMDL process and methodologies for addressing
the dynamic rainfall-driven loadings, including CSOs and stormwater, as part of the watershed-based
approach.
COMPLETED:
4-6 years
A-5
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TMDL Framework for Action APPENDIX A: PART II
Item 810: Workshops
OVERVIEW:
OST and OWOW-led workshops would provide guidance to the Regions and States on the technical needs
for implementation of the TMDL process. Workshops could be tailored to meet Region-specific needs. At
least five workshops per year are recommended so that all Regions will have at least one workshop every
2 years. Because of funding limitations, it may be advantageous to offer workshops at a centralized facility
and require participants to pay a nominal fee to defray expenses. Two types of workshops are needed under
the technical assistance effort:
(a) Regional workshops: Each year a survey is conducted to determine specific regional training needs.
Training materials for these workshops are tailored to meet those specific needs, and workshops are
conducted at regional sites. The workshops may contain nontechnical as well as technical components.
Each year EPA has conducted four or five workshops so that a workshop is given in each region at least
once every two years. Capacities of these workshops are 30-35 persons with an approximate cost of $25-
35K per workshop.
(b) Information Exchange Workshop(s): Each year EPA conducts one or two workshops for information
exchange, critical issues, or planning purposes. For example, in FY '91 a workshop was held in Chicago
with national experts and the user community to define future TMDL program needs. Approximately
125 people (by invitation only) attended the workshop. Each year OST and OWOW meet with
Regional/State TMDL coordinators to discuss yearly activities, regulatory schedules, and implementation
problems and prospects.
ISSUES:
• Workshops are needed to address the specific requirements of TMDL development.
• Workshops should address the technical implementation of the phased approach including a range of
models from simple screening methods to more complex models.
• Workshops can be used to develop consensus on future programmatic needs.
COMPLETED: Continuing
A-6
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TMDL Framework for Action APPENDIX A: PART II
Item nil: Workshops on the Implementation of Contaminated Sediments Criteria
OVERVIEW:
Contaminated sediments have the potential to cause toxicity, bioaccumulation, and other water quality impacts
even when the surrounding water was initially in compliance with existing water quality criteria. Workshops
should be conducted for Regions and various Federal and State agency personnel to help implement
contaminated sediment criteria through the State WQS process and to bring contaminated sediment within the
TMDL process. Workshops would also identify modeling and other technical needs concerning contaminated
sediments. (EPA is currently working toward developing criteria for contaminated sediments. Guidance
development is proposed in Item #5.)
ISSUES:
• Workshops are needed to present contaminated sediment criteria to the Regions/States.
• Workshops are needed to address the technical issues related to contaminated sediment.
• Technical needs for addressing contaminated sediments within the context of the TMDL process need to
be identified.
COMPLETED:
3 years
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TMDL Framework for Action APPENDIX A: PART II
Item #12: Direct Support to High-Priority TMDL-Related Court Cases
OVERVIEW:
HQ would provide expert support and consulting services for selected TMDL-related court cases, including
modeling and related monitoring. Many of the court cases of the past involved issues related to the
appropriateness of water quality standards (WQSs) and modeling/monitoring assumptions. HQ assistance is
provided on a case-by-case basis to improve the technical defensibility of die TMDL. The assistance may
consist of (a) finding and using experts, (b) selecting and simulating with appropriate models, (c) assisting
in generating monitoring data needed for the models, (d) interpreting model output, and (e) presenting
TMDLs in the public participation process.
ISSUES:
• High-priority TMDLs may require expert assistance for interpretation of WQSs, model selection, and
model application and/or development.
• Expert review can be used to evaluate the TMDL development methodology.
• Expert assistance may be required to develop technically defensible TMDLs.
COMPLETED:
Continuing
A-8
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TMDL Framework for Action APPENDIX A: PART II
Item #13: TMDL SWAT Team
OVERVIEW:
The surface water assessment technical (SWAT) team will consist of a team of experts who are familiar with
the technologies required for TMDL development. The SWAT team will provide short-term expertise to
EPA Regions, States, and local governments that are developing targeting programs and TMDLs (with special
emphasis on nonpoint sources) under the 303(d) program. The technical assistance will be provided primarily
on a phone-in basis. Other advantages of the SWAT team approach include opportunities to field-test new
technology and user feedback.
ISSUES:
• High-priority TMDLs may require expert assistance for interpretation of WQSs, model selection, and
model application and/or development.
• Successful development and implementation of TMDLs, through expert assistance, can provide positive
examples to the local State or Region.
• Expert review can be used to evaluate the TMDL development methodology.
• Expert assistance may be required to develop technically defensible TMDLs.
COMPLETED:
Continuing
A-9
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TMDL Framework for Action APPENDIX A: PART II
Items #14-18: Information Exchange
OVERVIEW:
Regions and States will be assisted in implementing TMDLs by providing access to information on other case
studies, court cases, and related modeling studies. This service includes development of a clearinghouse, data
bases, annotated bibliographies, and reviews of recent model applications.
• Coordination with Regions and States on the TMDL process. OST and OWOW will work with the
Regions and States on developing new technologies to support the TMDL process.
• Case study examples. Case studies are proposed for inclusion in TMDL guidance (see Item #2). There
is an immediate need for technical assistance to the Regions and States. By means of information
exchange, case study examples will be provided to the Regions and States on an accelerated basis.
• Model reviews. Description and testing of models are proposed for inclusion in Item #2. An OWOW
project is under way to review available models for TMDL screening. A summary document will be
provided to the Regions and States on an accelerated basis.
• Electronic bulletin board: A TMDL special interest group (SIG) is in the process of being established
as a part of the NFS Bulletin Board System (BBS).
• Legal clearinghouse: Information on current and/or pending lawsuits will be provided to Regions and
States on a continuing basis.
ISSUES:
• Information is available on models and related studies that might be helpful to the Region/States in the
development of TMDLs.
• Existing information should be compiled and disseminated to the Regions/States in the form of reports.
COMPLETED:
Continuing
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TMDL Framework for Action APPENDIX B
APPENDIX B
RESEARCH NEEDS
PART I - MODEL INTEGRATION AND
RELATED NEEDS
PART n - TECHNOLOGY TRANSFER
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TMDL Framework for Action APPENDIX B: PARTI
Item 819: Modd Integration
OVERVIEW:
Multiple models are often needed to evaluate TMDLs. Pre- and post-processors should have the capability
to link model input and output so that models can be run in series. Although models are available to address
most components of watershed-based analysis, each model is designed for a specific need. Models are not
currently designed to be used in a combined fashion (i.e., integrated approach). The watershed-based
approach will often require that multiple models be used to evaluate a watershed. To facilitate this process
pre- and post-processors need to be developed to link model input and output. For example, output from
SWMM (a watershed model) could be reformatted to provide input to WASP4 (a water quality model).
Likely combinations of models should first be selected. Data management needs could then be incorporated
into pre- and post-processor development (see also Item #32).
The CORMIX mixing zone model is currently distributed as three models. Future work will combine the
three models into one. A single user's manual and documentation will be prepared for the new combined
model.
Screening models are needed for the initial targeting phase of the TMDL development process. These
models, although limited in accuracy, require minimum data collection and can be used effectively in the
preliminary stages of TMDL development. A review of models has been initiated in Item. #16. Simple
screening level models are available, however many are site-specific, lack detailed documentation, and are
not generally distributed.. In this task a screening methodology will be developed, building on available
models. Components of the screening model may include enhanced capabilities for data retrieval from EPA
mainframe resources, a user-friendly interface, output statistics and graphics, and a detailed user's manual.
The development of a screening model has been initiated in cooperation with Region IV.
ISSUES:
• Used separately, models may provide a fragmented picture of water quality.
• Improved data management techniques would facilitate the use of multiple models for watershed-based
assessments.
• User friendly screening models are needed to assist the Regions and States in the initial phases of the
TMDL development process.
• Screening model development and support was designated as a high priority item by the Regional TMDL
coordinators.
COMPLETED:
5 years
B-l
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TMDL Framework for Action APPENDIX B: PARTI
Item #20: Ecological Models
OVERVIEW:
A few ecological models should be evaluated, verified, and selected for future support and development by
EPA. Ecological restoration and predictive modeling of ecological response are rapidly emerging areas of
research. The role of predictive models, however, is not necessarily to precisely quantify or to establish
causality, but to communicate the relationships between ecological restoration efforts and the resulting
benefits. For this reason, simple empirical relationships, as opposed to detailed, deterministic approaches,
are generally recognized as being more important.
Modeling efforts to date have mostly focused on predicting the benefits of restoration. With the aid of
simulations that combine the physical habitat preferences of riverine organisms and predictions of changes
in hydraulic patterns after structure placement, the available habitat can be estimated. Response factors are
used to weigh tolerances to certain conditions at each mitigation site. Most ecological response models,
however, are not at the stage of predicting "true" ecological response (i.e., changes in production, biomass,
recruitment, etc.), but offer stream managers a scale by which to compare relative magnitudes of
improvement or success of restoration efforts.
One model that could be used to predict ecological response in the near future, if it were possible to construct
"suitability for optimal colonization curves," is the Physical Habitat Simulation (PHABSIM). PHABSIM is
maintained by the U.S. Fish and Wildlife Service as a portion of the Instream Flow Incremental
Methodology. Other models that may be suitable include the Ecological Population Dynamics Model
(LESLIEMATRICS), ERL-Athen's food chain model, and the FISHSED model (U.S. Fish and Wildlife).
The FISHSED model is capable of assessing spawning potential as a function of sediment embeddedness.
ISSUES:
• EPA does not currently support and/or distribute ecological models.
• Ecological modeling is an emerging science.
• Ecological models will be necessary to implement ecocriteria and promote habitat restoration.
COMPLETED:
7 years
B-2
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TMDL Framework for Action APPENDIX B: PARTI
Item #21: Data Access Tools
OVERVIEW:
Most models used to evaluate nonpoint source pollution require a broad array of input variables. In most
cases, data requirements include region- or site-specific information on rainfall, soil type, hydrology
(including stream flow), topography, and land use. Although data are available from national data bases, data
are not easily accessed by users from Regional, State, or local agencies. Data-access tools (software
packages) are needed so that data from national data bases can be more readily accessed and formatted for
use with models. As our data bases improve, data access tools will be upgraded as well. Ongoing
mainframe data base improvements that may be beneficial to the TMDL program include indexing of RF3
to STORET and PCS. Future enhancements may include streamflow and reservoir information associated
with RF3.
ISSUES:
• Watershed and water quality models often require data on rainfall, sdil type, hydrology (including stream
flow), topography, and land use/land coverage.
• Current access to national data bases is limited. The data, once accessed, cannot be easily formatted for
input to a model.
• Different Federal agencies maintain national data bases (e.g., USGS-flow, NWS-precipitation, USDA-
soils). (Note: Through an MOU, EPA has access to flow data from the USGS.)
• Some computerized data are incomplete on the national level.
• While national data bases reside on mainframe computers, typical NPS models are applied using PCs.
Therefore, access tools will need to operate in a multiplatform environment.
COMPLETED:
5 years
B-3
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TMPL Framework for Action APPENDIX B: PARTI
#22: Design Storm Event
OVERVIEW:
An interagency plan to develop a technically defensible selection process for storm design event(s) for
modeling urban, agricultural, and mixed land use areas should be initiated. The use of watershed models
using design storms may be appropriate in preliminary screening or design applications for the TMDL
process. The selection of the appropriate design storm that characterizes "critical" conditions for water
quality is complex, depending on site, antecedent conditions, and receiving water conditions. Design storm
applications of models can significantly reduce the level of effort for initial model analyses.
This activity is divided into four categories: (1) design storm selection for urban areas; (2) design storm
selection for agricultural areas; (3) design storm selection for mixed land use areas, and (4) design storm
selection for land under transition.
For each category the feasibility of defining a critical design storm for the TMDL process should be
investigated. A process for selecting the design storm should be identified and guidance developed. The
process could include the selection of multiple events for the purposes of developing a TMDL. In each, the
unique characteristics of the contributing land use would be considered in selecting the key design storm
parameters.
ISSUES:
• Design storm applications may be appropriate for preliminary screening and design applications.
• Model applications using design storms can reduce the level of effort for using models.
• In the short term, development of a design storm would facilitate the use of the AGNPS model for the
TMDL process.
• The characteristics of the "critical" design storm for the TMDL process must take into consideration key
parameters related to water quality and quantity. Parameters might include land use, watershed
characteristics (such as time of concentration), antecedent conditions (moisture content of soils and time
since last runoff event), precipitation, and runoff.
• Design storm development may vary depending on the contributing land use; therefore, separate
development of urban, agricultural and mixed land use events is recommended.
COMPLETED:
5 years
B-4
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TMDL Framework for Action APPENDIX B: PARTI
Item #23: Biological Criteria
OVERVIEW:
It is EPA's policy that States develop and implement biological criteria into their water quality standards.
Biological criteria or biocriteria may be expressed as numerical values or narrative expressions to describe
the biological integrity of reference aquatic communities for a specific designated aquatic life use. States have
been instructed to adopt minimum narrative biological criteria into their water quality standards during the
FY 91- FY 93 triennium. Biocriteria are intended to supplement rather than replace chemical and
lexicological methods. Impairments can be identified from a variety of sources including water column
contamination, sediment contamination, nonchemical impacts, and alteration of physical habitat. Because of
the unpredictable and fluctuating nature of storm events, measuring the biological community or using
biocriteria may provide a good measure of the cumulative in-stream effects caused by nonpoint sources,
CSOs, and storm water.
ORD and OW are currently working on an initiative to develop biocriteria for aquatic ecosystems.
Additional research on the development of biocriteria will provide technical assistance to the States. One goal
of the research is to directly link stresses with ecosystem dysfunction.
ISSUES:
• Biological indicators may be a more effective measure of water quality than traditional chemical-based
criteria.
COMPLETED:
7 years
B-5
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TMDL Framework for Action APPENDIX B: PARTI
Item #24: BMP Effectiveness
OVERVIEW:
The effectiveness of best management practices (BMPs) or other control measures required by a TMDL can
be determined only through regular monitoring and assessment activities. As TMDLs are implemented
through the phased approach, mitigation plans will need to be developed for control of nonpoint sources,
stormwater discharges, and CSOs. The control of rainfall-driven loadings relies on die effective
implementation of a wide variety of best management practices (BMPs). Participants at the Chicago
workshop identified the need for a compendium of BMPs (including follow-up monitoring data) and their
measured effectiveness. The NPS Branch is working on this topic through Coastal Zone Management Act
(CZMA) efforts. The CZMA guidance document includes a detailed assessment of the available information
on the effectiveness of BMPs. Little or no information is available on the effectiveness of many commonly
used BMPs. Since testing on the effectiveness of BMPs is often limited to only a few regions of the country,
widespread applicability is often questionable. BMPs need to be selected for further testing.
Models also have limited capabilities in the area of BMP assessment. Mitigation plans often incorporate a
variety of BMPs throughout a watershed. Watershed models are typically used to evaluate the ability of the
mitigation plan to meet the required TMDL. Existing models (e.g., HSPF and SWMM) can evaluate BMPs
such as detention ponds based on sediment deposition. They do not account for the more complex chemical
and biological removal typical of wet ponds or created wetlands. Models need to be enhanced/developed to
allow for the evaluation of mitigation plans.
ISSUES:
• BMPs are needed to implement controls for nonpoint sources, stormwater discharges, and CSOs.
• Limited information is available on the effectiveness of some BMPs.
• Models typically do not estimate biological and chemical pollutant removal by BMPs.
COMPLETED:
10 years
B-6
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TMDL Framework for Action APPENDIX B: PARTI
Item 825: Model Revision
OVERVIEW:
*
Many of the currently supported EPA and USDA models are based on older techniques for calculation of
runoff, erosion, nutrient and chemical transport. Research has been ongoing in improving these algorithms,
particularly in the areas of air/water, sediment/water, and ground/surface interfaces. Existing models should
be selectively evaluated for areas that need to be updated. Models should be revised and improved
accordingly. This type of updating will enhance the capability of the models and improve their accuracy.
ISSUES:
• Model components should be enhanced with new technology as it becomes available.
• Algorithms could be added or improved in the areas of air/water, sediment/water, and ground/surface
interfaces.
• The air/water interface component could be improved, especially in the area of chemical volatilization.
• Modeling of the sediment/water interface is crucial to the evaluation of pollutant resuspension and mixing
due to storm events. Sediment-associated pollutants can constitute a significant source of pollutants in
receiving waters.
• Modeling of the interface between ground water and surface water is necessary for the understanding of
nonpoint source processes. When management practices are applied, the tradeoff between ground water
and surface water loadings must be carefully evaluated.
• Additional areas where updating would be appropriate include: adding variable complexity capability,
modeling of snow melt processes, and evaluating best management practices.
COMPLETED:
5 years
B-7
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TMDL Framework for Action APPENDIX B: PART I
#26: Adaptation of Models to CIS Platforms
OVERVIEW:
CIS is an excellent tool for the integration of data from different sources. (Developing input data files for
models and preparing graphs summarizing results can be a time-consuming effort.) At this time, few models
operate in a GIS environment (AGNPS is one exception). To improve the portability of information into
models and results from one model to another, our goal is to eventually update all EPA-supported models
to operate in a common (GIS) environment. GIS systems and remote sensing data also provide analysis
opportunities that do not exist with traditional modeling approaches.
ISSUES:
• EPA and SCS currently support ARC/INFO (vector-based) and GRASS (raster-based) as the GISs of
choice, respectively. Tools for converting from raster- to vector-based data and vice versa are therefore
needed.
• Because only limited staff with experience in GIS are available and initial costs for data entry are high,
current projects tend to experience a slow turnaround. As models are converted to a GIS environment,
additional effort on staff training will be necessary.
• A significant number of models will need to be revised to achieve this goal.
• Access tools will also need to link remote sensing data with models.
• The usefulness of remote sensing data for model verification and two-dimensional mixing zone modeling
should be explored.
• The potential for multiplatform data (LANDSAT TM and SPOT PAN) integration should be explored.
COMPLETED:
10 years
B-8
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TMDL Framework for Action APPENDIX B: PARTI
Item #27: Sediment Quality Models
OVERVIEW:
Contaminated sediment criteria are currently under development by EPA. Workshops and guidance to
support the implementation of contaminated sediment criteria are recommended under Items #5 and #11.
Impacts due to clean sediment deposition on cold and warm water fisheries are also an emerging concern (see
Item #6). With greater emphasis on the control of sediment impacts, improved tools will be required as well.
Models will be needed to evaluate the washoff and transport of clean and contaminated sediments. The EPA
HSPF watershed model has the ability to model erosion from land areas and sediment transport in rivers and
fully mixed reservoirs. The SWMM model has more limited capabilities in area of erosion and sediment
transport. The water quality models such as WASP4 have the most severe limitations with regard to sediment
transport.
A research plan should first be developed to identify and prioritize model research needs. The workshop
described in Item #11 will provide input on the modeling and other technical needs concerning contaminated
sediments. The research plan should then be implemented by ORD.
ISSUES:
• Contaminated and clean sediments can have adverse impacts on aquatic ecosystems.
• Tools are needed to evaluate sediment and associated pollutant transport in rivers, lakes and estuaries
• Water quality models currently supported by EPA have limited capabilities in the area of sediment
transport.
COMPLETED:
5 years
B-9
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TMDL Framework for Action APPENDIX B: PARTI
Item #28: TMDL Model Testing
OVERVIEW:
Models for the TMDL process need to be field-validated in various regions under a variety of land uses and
soil types. Verified model applications will help to increase user confidence and understanding of the model
limitations. Case studies are needed to evaluate the usefulness and applicability of models in the TMDL
process. A number of simpler screening-level models will be selected for testing. Model testing will be
performed in cooperation with the Regions and States to evaluate site specific concerns. The results of the
model testing will be compiled and provided to the Regions/States as part of the information exchange
program.
ISSUES:
• Models are currently difficult to apply, particularly for screening purposes, because of the lack of
guidance on input parameters.
• Model testing would increase user confidence in models.
• Model testing would assist in the development of default parameters.
• Model testing could also be used to identify technical areas for future model upgrades.
COMPLETED:
5 years
B-10
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TMDL Framework for Action APPENDIX B: PARTI
Item #29: Guidance on Default Parameter Selection
OVERVIEW:
Initial input parameters for each model application are difficult to select. For screening applications with
limited monitoring data few default parameters are available. As the need for screening applications
increases, as part of the phased TMDL process, additional information for parameter selection would be
valuable. Default parameters need to be defined for various regions, land uses, and soil types. Currently
EPA-supported models such as HSPF and SWMM have limited guidance on input values particularly in the
areas of pollutant accumulation, washoff, and transport. Other models, such as the USDA models, would
also benefit from additional documentation of default parameters for input. Because of the variability of such
inputs, the development of default parameters must take into account regional variations. A few carefully
selected ORD-led demonstration projects could be used to test models and develop the appropriate inputs
Parameters will be described as a range of possible input values based on documented research (see also Item
#26).
ISSUES:
• Models are currently difficult to apply, particularly for screening purposes, because of the lack of
guidance on input parameters.
• Default inputs are particularly lacking in the area of pollutant accumulation, removal, and transport.
• Default inputs should be developed on a regional basis.
COMPLETED:
10 years
B-ll
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TMDL Framework for Action APPENDIX B: PART I
Item #30: Conduct Training and Workshops
OVERVIEW:
Currently workshops on popular models (QUAL2E, WASP4, HSPF, etc.) are conducted by ERL-Athens and
ERL-Narragansett, usually at the ERL-Athens site. The workshops are typically conducted on one model at
a time. Sometimes, at Regional request, the modeling workshops are also conducted at Regional sites. Each
workshop can accommodate 35-45 trainees. To support the TMDL process, modeling workshops that
emphasize the application of models for TMDL development are needed. Additional workshops should be
added to provide training in the application of screening models. Minor modifications to the current format
would be sufficient to meet the needs of the TMDL program.
To make these workshops more effective, we need to improve the method of delivery by providing videotape
presentations, improving visual aids, and using other modern forms of animation techniques (see also Item
#33). With the expanding need to integrate point and nonpoint source modeling, there will be an increased
demand for training that includes nonpoint source modeling. As a result, the technology transfer program
will need to obtain additional expert support services (in-house or contractor support).
ISSUES:
• To support the TMDL process, there will be an increased demand for support/training on nonpoint source
modeling.
• Current workshops are oriented toward point source modeling or specific models for nonpoint source
assessments. The diversity of workshops will need to be expanded to include nonpoint source modeling
with particular emphasis on its integration with the TMDL process. This expertise may not currently
exist in-house, and expert support services may be necessary.
• To make use of limited resources, the Agency should consider innovative technology transfer methods
such as videotape presentations.
• It will be necessary to identify Region-specific training needs to identify the most appropriate support
services.
COMPLETED:
Continuing
B-12
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TMDL Framework for Action APPENDIX B: PARTI
Item #31: Innovative Delivery Systems for Technology Transfer
Prepare innovative delivery systems to improve visualization and animation of model output for effective
technology transfer.
OVERVIEW:
Hands-on training and telephone assistance are often needed to run the models that are distributed through
EPA. In response to this need, EPA conducts six or seven modeling workshops each year through its ORD
laboratories and another four to six workshops at Regional sites each year. They are open to anyone who
wishes to attend - from the public sector and the private sector, as well - and their popularity grows every
year. The Regional workshops are tailored to meet Region-specific needs and are also quite popular among
the user community. These workshops could reach even more potential users with videotaped presentations
that could be provided to a Region, a State, a local government, a university, or a private consultant to study
as needed, rather than waiting for a formally scheduled workshop. Using other modern forms of animation
techniques, demonstration diskettes, and computer-based training (CBT) will improve visualization of model
output and greatly enhance the speed and effectiveness of technology transfer.
ISSUES:
• Although more and more people request hands-on training and telephone assistance to run the models
distributed by EPA, the number of those potential users who actually receive training and assistance is
limited to a designated number of slots.
• The TMDL process will require training an increased number of potential users in the use of available
models.
• The development of hands-on tutorials and video taped presentations could facilitate the training of
potential users.
• Hands-on tutorials, provided on floppy disk, could be used to provide step by step guidance on model
use. Tutorials could be provided with or without a formal workshop.
• Video tapes of a classroom style presentation with appropriate audio visual aides could be used to train
model users. Tapes could be made available throughout die year supported by the technology assistance
personal at EPA (see also Item #35).
COMPLETED:
3-5 years
B-13
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TMDL Framework for Action APPENDIX B: PART II
Item #32: User's Manuals
Develop a user's manual separate from model documentation for each model supported and distributed by
EPA.
OVERVIEW:
Currently no simple user's manuals are available for the models that have been developed, supported, and
distributed by EPA. Instead, ORD distributes models with a complete documentation manual that is often
rather imposing. Knowledge of all of the assumptions that were involved in model development can be
helpful for many model applications. Even with such knowledge, however, hands-on training and telephone
assistance are often needed to run the model. A simple user's manual with several pertinent examples would
greatly facilitate widespread use of EPA-distributed models by States and local governments to develop
TMDLs. The user's manuals will include teaching aides such as tutorials which guide the user through a
sample application enhanced by graphics and animation.
ISSUES:
• Hands-on training and telephone assistance are often needed to run the models that are distributed by
EPA, even when users have a high level of computer literacy.
• User's manuals should be developed that clearly outline the steps required for model implementation.
• User's manuals should include example applications oriented specifically to the use of the model for the
TMDL process.
COMPLETED:
5 years
B-14
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TMDL Framework for Action APPENDIX B: PART II
Item if 33: Pn- and Post-Processor Development
Develop pre-processors and post-processors to enhance user-friendliness of old and new models.
OVERVIEW:
The development of user-friendly interfaces for computer models can greatly enhance the use of models for
TMDL development. Typically the data preparation, data input, and data interpretation phases of a modeling
project require a significant effort. Each model requires input in a unique format and presents results in
different ways. Therefore, experience with one model is not directly transferable to the next. Pre- and post-
processors should be developed for each supported model to facilitate model use using modern PC technology
for better graphics and animation. The pre-processor provides a computer interface with the following
features: menus for data entry, help screens for assistance in selecting input values, and a uniform format
for all models. The post-processor provides assistance in the interpretation of model results and allows for
the presentation of output data in tabular or graphical summaries. Options should be included for preparing
output in forms that can be read by other programs and models (i.e., interface with spreadsheets such as
Lotus 1-2-3 or input for receiving water models). (See Item #19.)
ISSUES:
• Models are currently difficult to use as a result of time-consuming data input preparation and data output
interpretation.
• Each model currently has different format requirements for data input and output, making transition from
one model to another difficult.
• Pre-processors can facilitate data input by providing consistent formats and user help.
• Post-processors can facilitate data output interpretation and provide interfaces with other programs and
computer models.
COMPLETED:
5 years
B-15
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TMDL Framework for Action APPENDIX B: PART II
Item #34: Technical Assistance
Augment the technical assistance program by streamlining our guidance and model clearinghouses, providing
expert support services, and expanding site-specific monitoring and model application studies.
OVERVIEW:
Demands on our technical assistance program are increasing, and they will continue to increase as more
groups and individuals use models that are distributed by EPA. To ensure that users' queries are answered
completely and efficiently, our guidance, model clearinghouses, and expert support services must be
expanded. We have already established a number of cooperative agreements with water quality model experts
for which in-house expertise is not available. These experts provide a valuable service to the user
community, and this service should continue on a larger scale so that more can be served.
ISSUES:
• The reliable use of models is enhanced by access to expert assistance for specific technical queries.
• It is through the technical assistance program that the weaknesses of our tools and technologies are
identified. Technical support provides an opportunity to compile and evaluate model weaknesses
providing input to future model development and revision.
COMPLETED:
Continuing
B-16
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TMDL Framework for Action APPENDIX B: PART II
Item if35: Joint Federal Interagency Model Clearinghouse
Initiate contacts and exploratory meetings with Federal agencies to establish a joint model distribution and
support center.
OVERVIEW!
In the area of watershed modeling, EPA supports complex models such as HSPF for urban and rural mixed
land use activities and SWMM for urban land use activities. USDA-SCS has developed six relatively simple
models that may be useful for TMDL assessments in rural areas. Agricultural Non-Point Source Pollution
Model (AGNPS), Simulator for Water Resources in Rural Basin-Water Quality model (SWRRBWQ),
Erosion-Productivity Impact Calculator (EPIC), Groundwater Loading Effects of Agricultural Management
Systems (GLEAMS), Chemicals, Runoff, Erosion from Agricultural Management Systems (CREAMS), and
Nitrate Leaching and Economic Analysis Package (NLEAP) are some that may be useful to EPA's TMDL
program. USGS has developed the DR3M-QUAL model and COE supports the STORM model.
To be consistent in our approach to watershed modeling and interpretation of modeling results, it would be
most helpful to coordinate our modeling activities with those of other Federal agencies. This would also
eliminate duplication of effort and facilitate technology transfer between the agencies as well as with the
public.
The ORD labs will be responsible for (1) initiating contacts and exploratory meetings with the appropriate
Federal agency personnel to prepare a Memorandum of Agreement to establish a joint model distribution and
support center, preferably at CEAM and (2) implementing the Memorandum of Agreement. Agencies which
could potentially participate in the Model Clearinghouse include: Army Corps of Engineers, US Department
of Agriculture, USDA/Forest Service, US Geological Survey, Bureau of Land Management, and the Bureau
of Reclamation.
ISSUES:
• The reliable use of models is enhanced by access to expert assistance for specific technical queries.
• Numerous Federal agencies support the development, distribution, and use of various watershed models
(i.e., EPA, USDA, COE, USGS). Our efforts need to be coordinated to ensure that the public receives
consistent technical advice with respect to watershed modeling, duplication of effort is minimized, and
technology transfer between agencies will occur.
COMPLETED:
Continuing
B-17
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