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Total Maximum Daily Loads with Storm water Sources;
A Summary of 17 TMDLs
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Total Maximum Daily Loads with Storm water Sources:
A Summary of 17 TMDLs
July 2007
EPA 841-R-07-002
Watershed Branch (4503T)
Office of Wetlands, Oceans and Watersheds
U.S. Environmental Protection Agency
1200 Pennsylvania Avenue NW
Washington, DC 20460
Document posted at:
www.epa.gov/owow/tmdl/techsupp.html
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Table of Contents
Introduction 1
Summary Table of 17 TMDLs with Stormwater Sources (TMDLs listed by model complexity) 2
Summary Table of 17 TMDLs with Stormwater Sources (TMDLs listed by region) 5
EPA Region 1
Eagleville Brook, CT 8
Mill River, Rooster River, and Sasco Brook, CT 10
Potash Brook, VT 12
EPA Region 2
Oyster Bay and Mill Neck Creek, NY 14
Swartswood Lake, NJ 16
EPA Region 3
Christina River Basin Watershed, DE/MD/PA (Nutrients and Low DO) 19
Christina River Basin Watershed, DE/MD/PA (Bacteria and Sediments) 22
Wissahickon Creek, PA 26
EPA Region 4
Harpeth River Watershed, TN 30
Pee Dee River Basin, SC 32
EPA Region 5
Lake Michigan Shoreline, IN 34
Lower Cuyahoga River, OH 36
EPA Region 6
Middle Rio Grande River, NM 39
EPA Region 8
Mantua Reservoir, UT 41
EPA Region 9
Los Angeles River Watershed, CA 44
San Diego Creek and Newport Bay, CA 47
EPA Region 10
Chester Creek, University Lake, and Westchester Lagoon, AK 50
Tualatin River Subbasin, OR 52
11
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Introduction
Throughout the US there are thousands of waters listed for impairments from stormwater
sources. The most common pollutants coming from stormwater sources include sediment, pathogens,
nutrients, and metals. These listed impaired waters need a Total Maximum Daily Load (TMDL), which
identifies the total pollutant loading that a waterbody can receive and still meet water quality standards.
The TMDL also allocates a specific pollutant wasteload to specific point and nonpoint sources. When
the TMDL is implemented, the stormwater wasteload allocation is implemented via the National
Pollutant Discharge Elimination System (NPDES) stormwater permitting system. States and EPA
Regions have used a variety of methods to develop stormwater source TMDLs during the past decade.
With the expansion of NDPES Phase II stormwater to smaller municipalities and smaller construction
activities, there has been increasing demand for more detailed quantification of stormwater allocations in
TMDLs that are more useful for implementation in NDPES permits.
This report summarizes 17 TMDLs that have been developed for stormwater sources in 16 states
throughout the country during the past eight years. They represent a range of pollutants, models used,
and different allocation and implementation methods that will be helpful to TMDL practitioners and
NPDES permitting agencies and permittees as they develop and implement new stormwater source
TMDLs.
For information about the TMDLs in this summary, please contact Christine Ruf
(ruf.christine@epa.gov) and Menchu Martinez at EPA Headquarters (martinez.menchu-c@epa.gov)
For additional information about TMDLs, please contact the following Regional Coordinators:
Region 1 - Steve Winnett (winnett.steven@epa.gov)
Region 2 - Antony Tseng (tseng.antony@epa.gov)
Region 3 - Tom Henry (henry.thomas@epa.gov)
Region 4 - William Melville (melville.william@epa.gov)
Region 5 - Dean Maraldo (maraldo.dean@epa.gov)
Region 6 - Curry Jones (jones.curry@epa.gov)
Region 7 - Bruce Perkins (perkins.bruce@epa.gov)
Region 8 - James Ruppel (ruppel.james@epa.gov)
Region 9 - Peter Kozelka (kozela.peter@epa.gov / Terry Fleming (fleming.terrance@epa.gov)
Region 10 - Bruce Cleland (cleland.bruce@epa.gov) / Laurie Mann (mann.laurie@epa.gov)
Disclaimer
This document provides technical information to TMDL practitioners who are familiar with the relevant
technical approaches and legal requirements pertaining to developing TMDLs and refers to statutory and
regulatory provisions that contain legally binding requirements. This document does not substitute for
those provisions or regulations, nor is it a regulation itself. Thus, it does not impose legally binding
requirements on EPA or States, who retain the discretion to adopt approaches on a case-by-case basis
that differ from this information. Interested parties are free to raise questions about the appropriateness
of the application of this information to a particular situation, and EPA will consider whether or not the
technical approaches are appropriate in that situation
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Summary Table of 17 TMDLs with Stormwater Sources
USEPA, OWOW, Watershed Branch
April 2007
(TMDLs listed by model complexity)
Region State TMDL Name/Waterbody
R1 VT Potash Brook (2006)
TMDL pollutant(s)
Models
Simple Models
Biological Impairment;
flow as surrogate for SW
pollutants
GWLF for flow volume w/
reference stream; GIS
watershed delineation; P8-
UCM; FGA
NPDES Permit, Allocation Method,
Implementation Plans
^IIIJ^H
VT state watershed permit using adaptive
management; permit to specify type, location,
and implementation of BMPs to achieve flow
reductions; comprehensive monitoring
program.
R1
CT
Eagleville Brook (2007)
Biological Impairment;
Impervious Cover as
surrogate for SW
pollutants
Percent impervious cover; GIS
watershed delineation;
ArcView® Impervious Surface
Analysis Tool
Specific recommendations for voluntary
actions to reduce impact of impervious cover
using adaptive management (backup is
potential state permit); DEP biomonitoring on
rotating basin schedule.
R1
CT
River, Rooster River, Sasco
Brook (2005)
E. coli
(geometric mean; Single
Sample Maximum)
Criteria curve
WWTP; MS4 & SW minimum control
measures in SWMPs, & guidance on septic
systems & nuisance wildlife.
R2
NJ
Swartswood Lake (2005)
Phosphorus
Reckhow's Empirical Modal;
Reference Condition
(Watershed)
Potential implementation measures for
nonpoint source categories (e.g., land use -
specific SW runoff, septic tanks & internal
loading).
R4
SC
Pee Dee River Basin (2005)
Fecal Coliform
(geometric mean)
Load Duration Curve
WWTPs; MS4s; SSOs; MS4 WLAs expressed
as % reduction goal; can use LDC to identify
appropriate implementation.
R4
TN
Harpeth River (2002)
Sediment (narrative)
Target: TSS or turbidity
for WWTP;
average annual sediment
load for MS4/construction
Watershed Characterization
System Sediment Tool
23 WWTPs; Phase I & II MS4s; 33
Construction GP; WLA for construction &
MS4s average annual sediment load for given
subwatershed. Implementation to be done
within TN watershed approach, 5-yr cycle of
planning, monitoring & assessment, etc.
R6
Middle Rio Grande River (2002)
Fecal Coliform
(geometric mean; Single
Sample Maximum)
Hyrdotech® Computer
Program
Mass Balance
WWTPs, 4 "discrete SW conveyance";
Phase I MS4 Albuquerque; TMDL establishes
separate numeric targets for each SW
conveyance; SW permit lists requirements to
address TMDL, including monitoring for BMP
effectiveness.
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Region
R8
R9
1 \\J
State
UT
CA
\jr\
TMDL Name/Waterbody
Mantua Reservoir (2003)
San Diego Creek and Newport
Bay (1999)
TMDL pollutant(s)
Total Phosphorus,
Dissolved Oxygen, and
pH
Nutrients (phosphorus &
nitrogen)
Models
TSI; Steady-state mass
balance; chlorophyll a; Secchi
depth response model
Ma<;<; Ralanrp
IVIQOO LJCUQI IWO
NPDES Permit, Allocation Method,
Implementation Plans
NPDES fish hatchery (limits for sediment);
pump station for agricultural runoff; WLA for
phosphorus reductions based on best
professional judgment.
Industrial permits; MS4 (Orange county);
Individual Permits for nurseries and other
NPDES permittees; level of nutrient
management plans for agriculture operations;
SW co-permittees submit analysis BMPS to
meet targets; separate WLAs for TP for urban
areas and construction sites; WLA for TN for
urban runoff.
Mid-Range Models
R3
R5
R10
PA
IN
OR
Wissahickon Creek (2003)
Lake Michigan shoreline (2004)
Tualatin River Subbasin (2001)
Sediment & Nutrients
E. coli
Temperature, Fecal
Coliform, Total
Phosphorus, Ammonia,
Volatile Sollids
Nutrients: EFDC; modified
version of WASP; Sediments:
GWLF (ArcView) module to
simulate streambank erosion;
BasinSim with output for a
Streambank Erosion Simulation
Module; Reference Condition
(watershed)
EFDC
Event-based, unit load
hydrology model; Steady State
Water Quality Model; Streeter-
P; Mass Balance analysis;
"simple method"; Reference
Condition (stream); WQC&F
NPDES Individual (industrial and municipal
WWTPs); Phase I & Phase II; Sediment WLA
for each MS4 based on land use specific
loadings and streambank erosion. PA SW
management policy cited; no allocations for
construction general permit.
NPS only; upstream CSO inputs not
addressed; TMDL mentions some
implementation activities.
WWTP, CAFOs, MS4; WQ Mgmt Plan
describes specific mgmt measures and source
categories; allocations estimated using a
variety of methods based on pollutant.
Complex Models
R2
R3
NY
DE, MD,
and PA
Oyster Bay and Mill Neck Creek
(2003)
Christina River (2006)
Pathogens
(90 percentile criteria)
Nutrients and Low
Dissolved Oxygen
Bacteria, Sediment
SWMM; WTM
EFDC; HSPF; SWMM;
Reference Condition
(watershed)
WWTPs; requirements for MS4s to go beyond
6 min. measures; shellfish & beach monitoring.
WWTPs, CSO, MS4s; WLAs allocated by land
use distribution in each municipality; PADEP
has a proposed SW mgmt policy, but not
required; SW WLA includes MS4 and nonpoint
source loadings.
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Region
State
TMDL Name/Waterbody
TMDL pollutant(s)
Models
NPDES Permit, Allocation Method,
Implementation Plans
R5
OH
Lower Cuyahoga River (2003)
Phosphorus, Nutrients,
Fecal Coliform
LDC; HYSEP;
SWAT; Multi SMP; XP-SWMM;
WASP
WWTP, MS4, CSOs; LDC used for MS4
allocations; Implementation actions include
measures and timelines for monitoring,
tracking & implementation.
R9
CA
Los Angeles River Watershed
(2005)
Metals (copper (Cu), lead
(Pb), zinc (Zn), cadmium
(Cd), and selenium (Se)
EFDC; LDC; LSPC; WASP
WWTPs, +1600 other NPDES permittees;
MS4s; Indus & construction SW permittees;
MS4s not given a specific WLA but share
responsibility with others for total WLA per
subwatershed. Detailed Implementation Plan
has agreement between 18 municipalities to
implement SW regulations jointly; monitoring
components with identified responsible
entities.
R10
AK
Chester Creek, University Lake,
and Westchester Lagoon (2005)
Fecal Coliform
(geometric mean or 10% not
to exceed)
MS4s; allocations based on modeling highest
loads; 3 implementation scenarios modeled—
(1) with public education, (2) with increased
street sweeping frequency and efficiency, &
(3) combination of first two. Provides info on
BMPs and applicability in cold climates.
Follow-up monitoring to track implementation
& BMP effectiveness.
MODELS:
ArcView® Impervious Surface Analysis Tool
Basin Sim
Criteria Curve: Cumulative Relative Frequency Distribution
EFDC: Environmental Fluid Dynamics Code
Event Based Unit Load Hydrology Model
FGA: Future Growth Analysis
GIS Watershed Delineation
GWLF: Generalized Watershed Loading Function
HSPF: Hydrologic Simulation Program Fortran
Hydrotech® Computer Program
HYSEP: Streamflow Hydrograph Separation and Analysis
LDC: Load Duration Curve Approach
LSPC: Loading Simulation Program in C++
Multi-SMP: Multiple Discharge Version of the Simplified Method Program
Percent Impervious Cover Method (ENSR 2005; CWP 2003)
P8- UCM: PS-Urban Catchment Model
Reckhow's Empirical Model
Reference Condition
Secchi Depth Response Model
Simple Method: Simple Method
Steady State Water Quality Model
Streeter P: Streeter Phelps equation
Streambank Erosion Simulation Module
SWAT: Soil and Water Assessment Tool
SWMM: Stormwater Management Model
TSI: Carlson's Trophic State Index
WASP: Water Quality Analysis Simulation Program
WQC&F: Water Quality Criteria and Flow Approach
WCS: Watershed Characterization System Sediment Tool
WTM: Watershed Treatment Model
USEPA Contacts Christine Ruf (ruf.christine@epa.gov); Menchu Martinez (martinez.menchu-c@epa.gov)
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Summary Table of 17 TMDLs with Stormwater Sources
USEPA, OWOW, Watershed Branch
April 2007
(TMDLs listed by region)
Region
State
TMDL Name/Waterbody
TMDL pollutant(s)
Models
NPDES Permit, Allocation Method,
Implementation Plans
R1
CT
Eagleville Brook (2007)
Biological Impairment;
Impervious Cover as
surrogate for SW
pollutants
Percent impervious cover; GIS
watershed delineation;
ArcView® Impervious Surface
Analysis Tool
Specific recommendations for voluntary
actions to reduce impact of impervious cover
using adaptive management (backup is
potential state permit); DEP biomonitoring on
rotating basin schedule.
R1
CT
River, Rooster River, Sasco
Brook (2005)
E. coli
(geometric mean; Single
Sample Maximum)
Criteria curve
WWTP; MS4 & SW minimum control
measures in SWMPs, & guidance on septic
systems & nuisance wildlife.
R1
VT
Potash Brook (2006)
Biological Impairment;
flow as surrogate for SW
pollutants
GWLF for flow volume w/
reference stream; GIS
watershed delineation; P8-
UCM; FGA
VT state watershed permit using adaptive
management; permit to specify type, location,
and implementation of BMPs to achieve flow
reductions; comprehensive monitoring
program.
R2
NY
Oyster Bay and Mill Neck Creek
(2003)
Pathogens
(90 percentile criteria)
SWMM; WTM
WWTPs; requirements for MS4s to go beyond
6 min. measures; shellfish & beach monitoring.
R2
NJ
Swartswood Lake (2005)
Phosphorus
Reckhow's Empirical Modal;
Reference Condition
(Watershed)
Potential implementation measures for
nonpoint source categories (e.g., land use -
specific SW runoff, septic tanks & internal
loading).
R3
DE, MD,
and PA
Christina River (2006)
Nutrients and Low
Dissolved Oxygen
Bacteria, Sediment
EFDC; HSPF;
Reference Condition
(watershed)
WWTPs, CSO, MS4s; WLAs allocated by land
use distribution in each municipality; PADEP
has a proposed SW mgmt policy, but not
required; SW WLA includes MS4 and nonpoint
source loadings.
R3
PA
Wissahickon Creek (2003)
Sediment & Nutrients
Nutrients: EFDC; modified
version of WASP; Sediments:
GWLF (ArcView) module to
simulate streambank erosion;
BasinSim with output for a
Streambank Erosion Simulation
Module; Reference Condition
(watershed)
NPDES Individual (industrial and municipal
WWTPs); Phase I & Phase II; Sediment WLA
for each MS4 based on land use specific
loadings and streambank erosion. PA SW
management policy cited; no allocations for
construction general permit.
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Region
State
TMDL Name/Waterbody
TMDL pollutant(s)
Models
NPDES Permit, Allocation Method,
Implementation Plans
R4
TN
Harpeth River (2002)
Sediment (narrative)
Target: TSS or turbidity
for WWTP;
average annual sediment
load for MS4/construction
Watershed Characterization
System Sediment Tool
23WWTPs;Phasel&IIMS4s;33
Construction GP; WLA for construction &
MS4s average annual sediment load for given
subwatershed. Implementation to be done
within TN watershed approach, 5-yr cycle of
planning, monitoring & assessment, etc.
R4
SC
Pee Dee River Basin (2005)
Fecal Coliform
(geometric mean)
Load Duration Curve
WWTPs; MS4s; SSOs; MS4 WLAs expressed
as % reduction goal; can use LDC to identify
appropriate implementation.
R5
Lake Michigan shoreline (2004)
E. coli
EFDC
NPS only; upstream CSO inputs not
addressed; TMDL mentions some
implementation activities.
R5
OH
Lower Cuyahoga River (2003)
Phosphorus, Nutrients,
Fecal Coliform
LDC; HYSEP;
SWAT; Multi SMP; XP-
WASP
WWTP, MS4, CSOs; LDC used for MS4
allocations; Implementation actions include
measures and timelines for monitoring,
tracking & implementation.
R6
Middle Rio Grande River (2002)
Fecal Coliform
(geometric mean; Single
Sample Maximum)
Hyrdotech® Computer
Program
Mass Balance
WWTPs, 4 "discrete SW conveyance";
Phase I MS4 Albuquerque; TMDL establishes
separate numeric targets for each SW
conveyance; SW permit lists requirements to
address TMDL, including monitoring for BMP
effectiveness.
R8
UT
Mantua Reservoir (2003)
Total Phosphorus,
Dissolved Oxygen, and
PH
TSI; Steady-state mass
balance; chlorophyll a; Secchi
depth response model
NPDES fish hatchery (limits for sediment);
pump station for agricultural runoff; WLA for
phosphorus reductions based on best
professional judgment.
R9
CA
Los Angeles River Watershed
(2005)
Metals (copper (Cu), lead
(Pb), zinc (Zn), cadmium
(Cd), and selenium (Se)
EFDC; LDC; LSPC; WASP
WWTPs, +1600 other NPDES permittees;
MS4s; Indus & construction SW permittees;
MS4s not given a specific WLA but share
responsibility with others for total WLA per
subwatershed. Detailed Implementation Plan
has agreement between 18 municipalities to
implement SW regulations jointly; monitoring
components with identified responsible
entities.
R9 CA San Diego Creek and Newport
Bay (1999)
Nutrients (phosphorus &
nitrogen)
Mass Balance
Industrial permits; MS4 (Orange county);
Individual Permits for nurseries and other
NPDES permittees; level of nutrient
management plans for agriculture operations;
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Region
State
TMDL Name/Waterbody
TMDL pollutant(s)
Models
NPDES Permit, Allocation Method,
Implementation Plans
R9
CA
San Diego Creek and Newport
Bay (1999)
Nutrients (phosphorus <
nitrogen)
Mass Balance
SW co-permittees submit analysis BMPS to
meet targets; separate WLAs for TP for urban
areas and construction sites; WLA for TN for
urban runoff.
R10
AK
Chester Creek, University Lake,
and Westchester Lagoon (2005)
Fecal Coliform
(geometric mean or 10% not
to exceed)
MS4s; allocations based on modeling highest
loads; 3 implementation scenarios modeled—
(1) with public education, (2) with increased
street sweeping frequency and efficiency, &
(3) combination of first two. Provides info on
BMPs and applicability in cold climates.
Follow-up monitoring to track implementation
& BMP effectiveness.
R10
OR
Tualatin River Subbasin (2001)
Temperature, Fecal
Coliform, Total
Phosphorus, Ammonia,
Volatile Sollids
Event-based, unit load
hydrology model; Steady State
Water Quality Model; Streeter-
P; Mass Balance analysis;
"simple method"; Reference
Condition (stream); WQC&F
WWTP, CAFOs, MS4; WQ Mgmt Plan
describes specific mgmt measures and source
categories; allocations estimated using a
variety of methods based on pollutant.
MODELS:
ArcView® Impervious Surface Analysis Tool
Basin Sim
Criteria Curve: Cumulative Relative Frequency Distribution
EFDC: Environmental Fluid Dynamics Code
Event Based Unit Load Hydrology Model
FGA: Future Growth Analysis
GIS Watershed Delineation
GWLF: Generalized Watershed Loading Function
HSPF: Hydrologic Simulation Program Fortran
Hydrotech® Computer Program
HYSEP: Streamflow Hydrograph Separation and Analysis
LDC: Load Duration Curve Approach
LSPC: Loading Simulation Program in C++
Multi-SMP: Multiple Discharge Version of the Simplified Method Program
Percent Impervious Cover Method (ENSR 2005; CWP 2003)
P8- UCM: PS-Urban Catchment Model
Reckhow's Empirical Model
Reference Condition
Secchi Depth Response Model
Simple Method: Simple Method
Steady State Water Quality Model
Streeter P: Streeter Phelps equation
Streambank Erosion Simulation Module
SWAT: Soil and Water Assessment Tool
SWMM: Stormwater Management Model
TSI: Carlson's Trophic State Index
WASP: Water Quality Analysis Simulation Program
WQC&F: Water Quality Criteria and Flow Approach
WCS: Watershed Characterization System Sediment Tool
WTM: Watershed Treatment Model
USEPA Contacts: Christine Ruf (ruf.christine@epa.gov); Menchu Martinez (martinez.menchu-c@epa.gov)
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Eagleville Brook
Stormwater Source TMDL (2007)
Connecticut, USEPA Region 1
TMDL at a Glance
Subbasin:
Watershed size:
Key beneficial uses:
Impaired by:
Pollutant(s):
Sources considered:
Model(s) used:
TMDL Web link:
TMDL Highlights
Affected water uses:
Applicable WQS:
Technical approach:
Not listed
2.4 square mile drainage area
Aquatic life
Stormwater related stressors
Combination of pollutants from developed areas, and other related
stressors (Stormwater runoff)
Impervious cover (1C) used as a surrogate measure to represent
Stormwater flows
ArcView® Impervious Surface Analysis Tool
TMDL Review available at http://www.epa.gov/NE/eco/tmdl/assets/pdfs/ct
eaQlevillebrook.pdf
Aquatic life
Class A waterbody. Aquatic life criteria states that a variety of
macroinvertebrate taxa and all functional feeding groups should
normally be well represented. Aquatic species presence and
productivity is only limited by natural conditions, permitted flow
regulation, or irreversible cultural impacts. The water quality should
sustain a diverse macroinvertebrate community of indigenous species.
Key indicator - Stormwater runoff from impervious surfaces.
Source assessment - Biological monitoring determined that this
waterbody did not meet aquatic life use goals. The state used the
assessment methodology outlined in the Connecticut Assessment and
Listing Methodology. The Inland Fisheries Division conducted fish
population surveys and observed low fish densities and large amounts
of habitat unoccupied by fish. The Bureau of Water Management also
conducted an extensive benthic invertebrate assessment and found
that the sites assessed had a Rapid Bioassessment Protocol III Benthic
Community Score <54% of the reference site, meaning the waterbody
is not meeting the aquatic life designated use.
8
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Model - ArcView® Impervious Surface Analysis Tool, developed by the
Nonpoint Education for Municipal Officials (NEMO) at the University of
Connecticut and the National Oceanic and Atmospheric Administration
(NOAA) Coastal Services Center, was used to calculate the percent 1C
for each of the three Eagleville Brook sections.
Allocations: • 12% 1C target applied to the stormwater drainage area affecting both
regulated and non-regulated sources in order to reduce pollutant loads
and restore hydrologic and biological integrity.
Eagleville Brook_01 require Anti-degradation, Eagleville Brook_02
requires a 21% reduction in % 1C through stormwater management,
and Eagleville Brook_03 requires a 59% reduction in % 1C through
stormwater management.
Implementation: • Requires adaptive management strategy, which includes: 1) reducing
1C where practical, 2) disconnecting 1C from the surface waterbody, 3)
minimizing additional disturbance to maintain existing natural
buffering capacity, and 4) installing engineered BMPs to reduce the
impact of 1C on receiving water hydrology and water quality.
Collect surface water chemistry and benthic macroinvertebrate data
from the Eagleville Brook by the Connecticut Department of
Environmental Protection (CTDEP) using the CTDEP Rotating Basin
Ambient Monitoring Strategy.
Cost: • Cost information is not available in the TMDL documentation.
References:
State of Connecticut Department of Environmental Protection. February 2007. A Total Maximum
Daily Load Analysis for Eagleville Brook, Mansfield, Connecticut.
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Mill River, Rooster River, and Sasco Brook
Stormwater Source TMDL (2005)
Connecticut, USEPA Region 1
TMDL at a Glance
Subbasin:
Watershed size:
Key beneficial uses:
Impaired by:
Pollutant(s):
Sources considered:
Model(s) used:
TMDL Web link:
TMDL Highlights
Affected water uses:
Applicable WQS:
Technical approach:
Allocations:
Southwest eastern
Mill River and Rooster River - 25 and 15 square miles, respectively; Sasco
Brook - 6 linear miles
Contact recreation
Bacteria
E. coli
Point sources - Phase II MS4; regulated urban runoff/storm sewers,
combined sewer overflow (CSO), dry weather overflows, and illegal
connections to Stormwater systems
Nonpoint sources - collection system failure, urban runoff/storm sewers,
on-site wastewater systems (septic tanks), domestic animals, and natural
wildlife
Cumulative Distribution Function Method
http://www.ct.QOv/dep/lib/dep/water/tmdl/tmdl final/swebasint
mdlfinal.pdf
Contact recreation
Geometric mean less than 126/100 ml, single sample maximum
576/100 ml (numeric). The TMDLs are applicable during the
recreation season from May 1 to September 30.
Key indicator(s) - E. coli
Source assessment - Ambient monitoring data confirmed that bacteria
densities are typically highest during the summer months.
Model - A cumulative distribution function method was used to
quantify the necessary bacteria density reduction. This procedure
allows the contribution of each individual sampling result to be
considered when estimating the percent reduction needed to meet a
criterion that is expressed as a geometric mean.
The analysis partitions the TMDL into wasteload and load allocations
(WLA and LA) using ambient water quality data during periods of high
and low Stormwater influence; the wet weather data were used to
calculate the WLA percent reductions, and the dry weather data were
used to calculate the LA percent reductions.
Using the cumulative distribution function method, each of the
waterbody monitoring sites (5) received average percent reductions as
WLAs and LAs to meet water quality standards.
10
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Implementation:
Cost:
References
Point source - Regulated stormwater received a WLA. Dry weather
flows from stormwater collection systems, illegal connections to
stormwater systems, and CSOs required a 100 percent reduction
because the management goal for these sources is elimination.
Permitted discharges of treated and disinfected domestic wastewater
received zero percent reductions.
Nonpoint source - Onsite septic received a LA. Natural sources (e.g.,
from wildlife) received a zero percent reduction.
Separate reduction goals are established for baseflow and stormwater
dominated periods, which can assist local communities in selecting
best management practices (BMPs) to improve water quality for each
of these conditions.
The technique used to allocate loads facilitates the use of ambient
stream monitoring data to track progress toward water quality goals.
It is expected that implementation of these TMDLs will be
accomplished through implementing the provisions of the MS4 Permit.
BMPs for the management of nonpoint sources include septic system
testing and maintenance, nuisance wildlife control plans, and pet
waste ordinances.
To guide TMDL implementation, a water quality monitoring program is
necessary. Typically, "event monitoring" is required of MS4 permits;
however, due to the logistical difficulty for municipalities it is often
times not the most efficient program to measure progress in achieving
water quality standards. Therefore, the Connecticut Department of
Environmental Protection encourages municipalities that are
implementing TMDLs to request approval for an alternative monitoring
program. The alternative program must be designed to accomplish
two objectives: (1) source detection and (2) quantification of progress.
Cost information is not available in the TMDL documentation.
State of Connecticut Department of Environmental Protection. 3 March 2005. A Total Maximum
Daily Load Analysis for the Mill River, Rooster River, and Sasco Brook. Hartford, CT.
Available at http://www.ct.QOv/dep/lib/dep/water/tmdl/tmdl final/swebasintmdlfinal.pdf
11
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Potash Brook
Stormwater Source TMDL (2006)
Vermont, USEPA Region 1
TMDL at a Glance
Subbasin:
Watershed size:
Key beneficial uses:
Impaired by:
Pollutant(s):
Sources considered:
Model(s) used:
TMDL Web link:
TMDL Highlights
Affected water uses:
Applicable WQS:
Technical approach:
Allocations:
Not listed
7.13 square miles
Aquatic life
Stormwater related stressors
Sediment and combination of pollutants found in urban Stormwater
Point sources - NPDES regulated and unregulated urban and developed
areas
Nonpoint sources - limited agricultural and open space
Reference Watershed Approach, PS-Urban Catchment Model to develop
Flow Duration Curve, Future Growth Analysis
TMDL Review available at http://www.epa.gov/NE/eco/tmdl/assets/pdfs
/vt/DOtashbrook.pdf
Aquatic life
• The impairment is based on biological indices so there is no numeric
pollutant criterion to use as the TMDL target. Instead, the in-stream
target is expressed as a measure of hydrologic condition believed to be
necessary to achieve the Vermont water quality criteria for aquatic life.
Key indicator - Sediment and mix of pollutants found in urban
Stormwater
Source assessment - Biological monitoring of the fish and
macroinvertebrate communities in reference sites to define the
biological community goals for specific stream types. The Vermont
Department of Conservation (VDEC) collected biological data from
1987 to 2004, and VDEC approved the use of biological data collected
by South Burlington from 2001 to 2004.
Model - Reference Watershed Approach whereby hydrologic targets
are developed by using similar "attainment" watersheds as a guide.
The "attainment" watersheds were selected using a careful statistical
analysis of the watershed characteristics of 15 candidate "attainment"
watersheds. Flow Duration Curves (FDC) were used to define
hydrologic targets. This approach compares FDC between an impaired
and appropriate attainment stream/watershed. The PS-Urban
Catchment Model was used to develop the FDC model outputs.
Land use based allocation approach, which divided the Potash Brook
watershed into three broad categories: Urban/Developed,
Agriculture/Open, and Forest/Wetland. The overall percent
reduction/increase in flows was distributed among these three categories
as follows: 1) zero allocation for Forest/Wetland, 2) 91% reduction from
Urban/Developed, wasteload allocation; and 3) 9% reduction from
Agriculture/Open, load allocation.
12
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Implementation: • Implemented through iterative, adaptive management approach
utilizing a watershed permit authorized by Vermont law.
State watershed permit will specify the type and location of BMPs
necessary to achieve the stormwater runoff reductions outlined in the
TMDL; conditions for BMP implementation will be included in all
applicable NPDES permits.
A comprehensive monitoring program will be used to measure
progress towards water quality standards and to amend the permits as
needed.
Cost: • Cost information is not available in the TMDL documentation.
References:
Vermont Department of Environmental Conservation. October 2006, Total Maximum Daily Load to
Address Biological Impairment Potash Brook (VT05-11) Chittenden County, Vermont.
13
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Oyster Bay and Mill Neck Creek
Stormwater Source TMDL (2003)
New York, USEPA Region 2
TMDL at a Glance
LONG ISLAND SOUND
| MILL NECK CfrEEt-
Subbasin:
Watershed size:
Key beneficial uses:
Impaired by:
Pollutant(s):
Sources considered:
Model(s) used:
TMDL Web link:
TMDL Highlights
Affected water uses:
Applicable WQS:
Mill Neck Creek watershed and Oyster Bay Harbor's drainage area includes
flows from Mill Neck Creek, Village of Bayville, Village of Centre Island,
Beekman Beach, Hamlet of Oyster Bay, and Village of Cove Neck
2,877 acres, including Oyster Harbor and Mill Neck Creek (Mill Neck Creek
itself is about 297 acres); Oyster Harbor and Mill Neck Creek have about
17 miles shoreline
Shellfish harvesting
Pathogens
Total Coliform
Point source - Three wastewater treatment plants (WWTPs) covered by
NYSDEC SPDES (New York State Department of Environmental
Conservation, State Pollution Discharge Elimination System) General
Permits; Stormwater discharges, drain pipes and culverts, from streets
and parking areas and direct overland runoff flows from street ends and
boat ramps (in 2003, fourteen municipalities submitted an application for
inclusion in the SPDES General Permit for Stormwater discharges from
Municipal Separate Storm Sewer Systems (MS4s) and one industrial
entity, Commander Oil Company, which has numerous large oil storage
tanks and an off-loading dock.
Nonpoint source - 39 residential and 4 other units dispose of domestic
waste using cesspools; freshwater inputs from several creeks and ponds;
boats, marinas, and mooring areas; wildlife and waterfowl; and
agricultural and domestic animals.
Stormwater Management Model and Watershed Treatment Model
http://www.dec.state. nv.us/website/dow/ovstbav.Ddf
Shellfish harvesting
A geometric mean of total coliform less than 70 most probable number
(MPN)/100 ml and an estimated 90th percentile value of total coliform
less than 330 MPN/100 ml (numeric). These standards are based on
total coliform data derived from a minimum of the 30 most recent
water samples. Based on analyses of historical data and the water
14
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Technical approach:
Allocations:
Implementation:
Cost:
References
quality data analysis conducted in this study, the 90th percentile
criterion is more difficult to meet than the geometric mean criterion;
therefore, this criterion is used as the goal for these TMDLs.
Key indicator(s) - Total coliform
Source assessment - The sources were primarily identified from a
shoreline survey conducted by NYSDEC in 1988. WWTPs contribute
less than one percent of the load; stormwater from rainfall events
accounts for about 88 percent; boats, marinas, and mooring areas
contribute about 11 percent; and waterfowl and horses contribute less
than 1 percent.
Stormwater Management Model (SWMM) - simulates the quantity and
quality of runoff produced by storms in urban watersheds and was
used to estimate loads from Mill Neck Creek and its tidal tributaries.
The water quality data used in the SWMM model was simulated by
developing total coliform accumulation rates for each of the land uses.
Watershed Treatment Model (WTM) - characterized point and nonpoint
sources and quantified pathogen loadings for the four zones within
Oyster Bay Harbor because of the lack of historical water quality data.
The WTM spreadsheets calculated pathogen load annually using a
series of runoff volume coefficients and pathogen loading estimates
derived from scientific literature.
The loading capacity was not exceeded for Mill Neck Creek and
tributaries and two of the zones in Oyster Bay Harbor zones, so the
wasteload and load allocations (WLA and LA) were established at
current loads.
Point source - In one of the Oyster Bay zones, the TMDL requires a
20 percent reduction in the stormwater load which included
stormwater drainage, and in another zone, the TMDL requires a 90
percent reduction in stormwater which included urban runoff.
Nonpoint source - In one of the zones in Oyster Bay, the TMDL
requires a 95 percent reduction in boat and marina loadings.
MS4s discharging to two of the zones within Oyster Bay Harbor will be
required to provide controls beyond the six minimum measures.
NYSDEC has proposed mitigation measures to reduce discharges from
boats and marinas. For example, it is anticipated that discharges from
boats and marinas will be reduced by designating the subject waters
as "no discharge" zones.
NYSDEC will continue its shellfish monitoring program at 39 stations to
assess compliance. Data collected through the beach monitoring
program at four beaches will also be used to assess the effectiveness
of controls.
Cost information is not available in the TMDL documentation.
New York State Department of Environmental Conservation (NYSDEC). September 2003. Pathogen
Total Maximum Daily Loads for Shellfish Waters in Oyster Bay Harbor and Mill Neck Creek,
Nassau County, New York. Available at
http://www.dec.state.nv.us/website/dow/ovstbav.Ddf
15
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Swartswood Lake
Stormwater Source TMDL (2005)
New Jersey, USEPA Region 2
TMDL at a Glance
.4..
Subbasin:
Watershed size:
Key beneficial uses:
Impaired by:
Pollutant(s):
Sources considered:
Model(s) used:
TMDL Web link:
Northwest Water Region
10,713 acres, excluding lake surface area (505 acres)
(1) maintenance, migration, and propagation of the natural and
established aquatic biota, (2) primary and secondary contact recreation,
(3) industrial and agricultural supply, (A) public potable water supply after
conventional filtration treatment and disinfection, and (5) any other
reasonable uses.
Phosphorus
Total phosphorus (TP)
Point source - There are no point sources in the watershed.
Nonpoint source - The TMDL identifies internal loading, septic tanks, and
Stormwater runoff as the primary contributors to total phosphorus to the
lake. The land uses considered for Stormwater runoff include
medium/high density residential, low density/rural residential,
commercial, mixed urban/other urban, and agricultural. Phosphorus from
air deposition was also considered, but it was not determined to be a
significant source.
Empirical model
http://oaspub.epa.QOv/tmdl/waters list.tmdl report?p tmdl id
=12411
TMDL Highlights
Affected water uses:
Applicable WQS:
Recreational, water supply, and aquatic life
Numeric (0.05 mg TP/L) and narrative water quality standards apply.
The state's nutrient narrative standard states, "except as due to
natural conditions, nutrients shall not be allowed in concentrations that
cause objectionable algal densities, nuisance aquatic vegetation,
abnormal diurnal fluctuations in dissolved oxygen or pH, changes to
the composition of aquatic ecosystems, or otherwise render the waters
unsuitable for the designated uses."
A target concentration, used to determine the loading capacity, was
estimated based on a comparison of peak-to-mean TP concentrations.
16
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Technical approach:
Allocations:
Implementation:
Cost:
Using annual average water quality data from 1994 and 2002-2004,
peak-to-mean ratios of 1.42 and 1.62, respectively, were calculated.
In previously established TMDLs by the New Jersey Department of
Environmental Protection (NJDEP), a target concentration of 0.03 mg/L
had been determined based on peak-to-mean ratios of 1.56 and 1.48
for two similar lakes—Strawbridge and Sylvan. Based on these data,
NJDEP determined that 0.03 mg/LTP is an appropriate target
phosphorus concentration for use in this TMDL and will assure that the
0.05 mg TP/L criterion will be met throughout the year.
Key indicator(s) - Total phosphorus
Source assessment - Current loads for nonpoint sources were
calculated by a unit areal load (UAL) methodology.
Model - An empirical model developed by K.H. Reckhow (1979) was
used to calculate the phosphorus loading capacity of the lake by
relating the annual phosphorus load to a steady-state in-lake TP
concentration. The model has previously been applied to north
temperate lakes with hydrologic, morphologic, and loading
characteristics similar to those of Swartswood Lake.
Point source - The wasteload allocation is set to zero because there
are no point sources in the watershed.
Nonpoint source - The following nonpoint sources received a 57
percent reduction: (1) septic tank systems, (2) internal loading, (3)
medium/high density residential, (4) low density/rural residential, (5)
commercial, (6) mixed urban/other urban, and (7) agricultural
The implementation plan includes: potential management strategies,
responsible entities, and funding options to address the three major
nonpoint sources of TP to the lake: stormwater runoff, septic tank
leakage, and internal loading.
The Swartswood Lake and Watershed Association have received Clean
Water Act Section 319(h) funding to install a hypolimnetic aeration
system, perform weed harvesting, and implement stormwater best
management practices. A regional stormwater management plan is
being developed for the Swartswood watershed through another
319(h) grant, which can serve as a foundation for future
implementation strategies.
The state's stormwater management rules establish a 300-foot special
water resource protection area (SWRPA) surrounding "category one"
(Cl) waters and their intermittent and perennial tributaries, and both
Swartswood Lake and Little Swartswood Lake are listed as Cl waters.
In the SWRPA, new development is typically limited to existing
disturbed areas to maintain the integrity of the Cl waterbody. For the
Townships of Hampton and Stillwater, NJDEP has imposed a fertilizer
ordinance that only allows the application of low phosphorus fertilizer
(see www.n1stormwater.org for the ordinance language).
"Phosphorus contributions from future development are expected to be
controlled through implementation of the Stormwater Management
Rules, which establish quality standards for [total suspended solids]
and nutrients."
Cost information is not available in the TMDL documentation.
17
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References:
New Jersey Department of Environmental Protection, Division of Watershed Management. August
31, 2005. Amendment to the Sussex County Water Quality Management Plan: Total
Maximum Daily Load to Address Phosphorus and Fish Community Impairments in
Swartswood Lake in the Northwest Region. Watershed Management Area 1. Available at
http://oaspub.epa.gov/tmdl/waters list.tmdl report?p tmdl id = 12411
Reckhow, K.H. 1979. Uncertainty Analysis Applied to Vollenweider's Phosphorus Loading Criterion.
J. Water Pollution Control Federation. 51(8):2123-2128.
18
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Christina River Basin Watershed
Stormwater Source TMDL (2006)
Pennsylvania, Delaware, and Maryland,
USEPA Region 3
(Nutrients and Low DO)
TMDL at a Glance
Subbasin:
Watershed size:
Key beneficial uses:
Impaired by:
Pollutant(s):
Sources considered:
Model(s) used:
TMDL Web link:
TMDL Highlights
Affected water uses:
Applicable WQS:
Delaware River
565 square miles
Primary contact recreation (swimming) and protection of aquatic life
(fishing) (designated by Pennsylvania Department of Environmental
Protection and Delaware Department of Natural Resources and
Environmental Control)
Nutrients, organic enrichment, and low dissolved oxygen (DO)
(Pennsylvania); nutrients and low DO (Delaware)
Nutrients and low DO
Point sources - Wastewater treatment plants (WWTPs), combined sewer
overflows (CSOs) and municipal separate storm sewer systems (MS4s)
Nonpoint sources - Septic systems, agricultural activities, and wildlife
sources
Hydrologic Simulation Program-Fortran (HSPF), XP-Stormwater
Management Model (XP-SWMM), and Hydrodynamic (and receiving water)
Model
http://www.epa.QOv/reQ3wapd/tmdl/pa tmdl/ChristinaMeetinq
TMDL/index.htm
Primary contact recreation and aquatic life
Numeric and narrative water quality standards (WQS) apply. There
are four regulatory agencies with applicable WQS in the Christina River
Basin—Pennsylvania Department of Environmental Protection (PADEP),
Delaware Department of Natural Resources and Environmental Control
(DNREC), the Maryland Department of the Environment (MED), and
Delaware River Basin Commission (DRBC).
Pennsylvania and Maryland allocation targets at PA-DE and MD-DE
state lines, respectively: Total nitrogen - 3.0 mg/L and total
phosphorus - 0.2 mg/L (Delaware WQS)
19
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Technical approach:
Key indicator(s)
Source assessment
Models
Allocations:
Point sources
Nonpoint sources
Implementation:
Nitrate-nitrogen allocation targets: 10 mg/L (Pennsylvania and
Delaware WQS)
Nitrogen and phosphorus allocation targets were based on minimum
and daily average DO WQS, which depend on the designated use
(Pennsylvania WQS)
DO allocation targets were based on DO WQS (Pennsylvania,
Delaware, and Maryland WQS)
Total nitrogen, total phosphorus, as well as DO, nitrate-nitrogen and
ammonia-nitrogen
CSOs - Nutrient loads from the 38 CSOs in the vicinity of the City of
Wilmington that discharge to the Christina River Basin were
determined using the flow rates calculated by the XP-SWMM model
(see below) and event mean concentrations calculated from storm
events monitored in 2003 and 2004.
MS4s - Most of the townships and boroughs within the Christina River
Basin in Chester County, PA, and all of New Castle County, DE, are
covered by the Phase II MS4 program regulations. To assess the
relative loads from different land uses within municipal boundaries, the
HSPF model (see below) incorporated an inventory of municipal land
use data as a proportion of the HSPF subbasins in which each
municipality resides.
The modeling framework used consisted of three major components:
(1) a watershed loading model, Hydrologic Simulation Program-Fortran
(HSPF), developed for each of the four primary subwatersheds in the
Christina River Basin by the U.S. Geological Survey (Senior and
Koerkle 2003a, 2003b, 2003c, 2003d); (2) a CSO flow model, XP-
Stormwater Management Model (XP-SWMM), developed by the City of
Wilmington; and (3) a hydrodynamic (and receiving water) model
developed using the computational framework of the Environmental
Fluid Dynamics Code (EFDC) (Hamrick 1992).
MS4s - Neither the PA nor the DE MS4 permits identify the boundaries
of the stormwater collection system contributing areas within each
municipality. Therefore, it is not possible to assign a wasteload
allocation (WLA) specific to the storm sewer collection areas within
each MS4 municipality. Because these systems have not yet been
delineated, the TMDL includes nonpoint source loadings in the WLA
portion of the TMDL. It is anticipated that the state's stormwater
program will revise the WLA into the appropriate WLA and load
allocation (LA) as part of the stormwater permit reissuance; however,
the overall reductions in the TMDL will not change.
CSOs - The annual average loads for CSO discharges (in kg per day of
total phosphorus and total nitrogen) were established to meet the total
phosphorus, total nitrogen, and DO WQS.
Non-MS4s - The non-MS4 point source permittee's WLAs for five-day
carbonaceous oxygen demand, ammonia, and total phosphorus are not
reduced from their permitted levels.
After the municipalities delineate their MS4 areas, the nutrient loads
associated with NPS may be separated from the WLA and moved to
the LA. The LA is not divided into subcategories in this TMDL.
There are state and local policies and regulations in place to help
ensure implementation of best management practices (BMPs). At the
20
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state level, PADEP has developed a Proposed Comprehensive
Stormwater Management Policy (appendix A of the TMDL) that
encourages implementation of BMPs for stormwater control to reduce
pollutant loadings, recharge groundwater tables, enhance stream
baseflow during drought periods, and reduce the threat of streambank
erosion and flooding. This policy seeks to integrate watershed
management plans with permitting programs.
Cost: • Cost information is not available in the TMDL documentation.
References:
Hamrick, J.M. 1992. A Three-dimensional Environmental Fluid Dynamics Computer Code:
Theoretical and Computational Aspects. Special Report 317. The College of William and
Mary, Virginia Institute of Marine Science.
Senior and Koerkle. 2003a. Simulation of Streamflow and Water Quality in the Brandywine Creek
Subbasin of the Christina River Basin, Pennsylvania and Delaware, 1994-98. U.S. Geological
Survey Water-Resources Investigations Report 02-4279.
Senior and Koerkle. 2003b. Simulation of Streamflow and Water Quality in the White Clay Creek
Subbasin of the Christina River Basin, Pennsylvania and Delaware, 1994-98. U.S. Geological
Survey Water-Resources Investigations Report 03-4031.
Senior and Koerkle. 2003c. Simulation of Streamflow and Water Quality in the Red Clay Creek
Subbasin of the Christina River Basin, Pennsylvania and Delaware, 1994-98. U.S. Geological
Survey Water-Resources Investigations Report 03-4138.
Senior and Koerkle. 2003d. Simulation of Streamflow and Water Quality in the Christina River
Subbasin and Overview of Simulations in Other Subbasins of the Christina River Basin,
Pennsylvania and Delaware, 1994-98. U.S. Geological Survey Water-Resources
Investigations Report 03-4193.
U.S. EPA Region III. 26 September 2006. Revisions to Total Maximum Daily Loads for Nutrient and
Low Dissolved Oxygen under High-flow Conditions: Christina River Basin Watershed,
Pennsylvania, Delaware, and Maryland. Philadelphia, PA. Available at
http://www.eDa.QOv/reQ3waDd/tmdl/Da tmdl/ChristinaMeetinqTMPL/index.htm
21
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Christina River Basin Watershed
Stormwater Source TMDL (2006)
Pennsylvania, Delaware, and Maryland,
USEPA Region 3
(Bacteria and Sediment)
TMDL at a Glance
Subbasin:
Watershed size:
Key beneficial uses:
Impaired by:
Pollutant(s):
Sources considered:
Model(s) used:
TMDL Web link:
TMDL Highlights
Affected water uses:
Applicable WQS:
BACTERIA
Delaware River
565 square miles
Primary and secondary contact recreation, public water supply, and
support of aquatic life
Bacteria and sediment
Bacteria and sediment
Point sources - Wastewater treatment plants (WWTPs), combined sewer
overflows (CSOs), and municipal separate storm sewer systems (MS4s)
Nonpoint sources - Septic systems, agricultural activities, wildlife, and
domestic pets
Hydrologic Simulation Program-Fortran (HSPF), XP-Stormwater
Management Model (XP-SWMM), and Hydrodynamic (and receiving water)
Model
httD://www.epa.QOv/reQ3waDd/tmdl/Da tmdl/ChristinaMeetinq
TMDL/index.htm
Primary and secondary contact recreation, public water supply, and
support of aquatic life
Pennsylvania - During the swimming season, from May 1 through
September 30, the 30-day geometric mean fecal coliform bacteria
levels must be less than the target value of 200 colony forming units
(cfu)/100 ml and not more than 10 percent of fecal bacteria
concentrations within a 30-day period can exceed 400 cfu/100 ml.
During the non-swimming season (October 1 through April 30), the
30-day geometric mean target level is 2,000 cfu/100 ml.
Delaware - The TMDL target endpoint for enterococcus bacteria is the
geometric mean concentration of 100 cfu/100 ml.
22
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SEDIMENT
Technical approach:
Key indicator(s)
BACTERIA
SEDIMENT
Source assessment
Models
BACTERIA
Maryland - For fresh waters, MD uses either enterococci or E. coli as
the bacteria indicator. For waters not designated as beaches, only the
steady state geometric mean indicator density for enterococci is 33
counts/100 ml and for E. coli, 126 counts/100 ml is the applicable
criterion.
The sediment TMDL endpoints are based on the reference watershed
method. Pennsylvania's water quality standards (WQS) include a
maximum 750 mg/L of total dissolved solids (TDS) and a monthly
average of 500 mg TDS/L year round for potable water supplies.
Fecal coliform (PA), enterococcus (DE), and E. coli or enterococcus
(MD)
Total suspended solids (TSS) (PA)
CSOs - Bacteria loads from the 38 CSOs within the vicinity of the City
of Wilmington that discharge to the Christina River Basin were
determined using the flow rates calculated by the XP-SWMM model
(see below) and event mean concentrations during two storm events
in 2003.
MS4s - An inventory of municipal land use data as a portion of the
HSPF (see below) subbasins in which the municipalities reside was
used to assess the relative loads of bacteria and sediment from
different land uses within municipal boundaries.
Septic systems - The potential annual bacteria load from
malfunctioning, as well as properly functioning, septic systems was
estimated.
Wildlife - Literature and empirical values were used to estimate wildlife
population densities for different land use categories. Monthly
adjustment factors were used to account for seasonal variations in
wildlife populations.
Domestic pets - The bacteria load from domestic pets was estimated
in the HSPF watershed model runoff from urban and residential areas.
Enterococcus - Three models were used to determine enterococcus
bacteria TMDLs for waters listed in Delaware: (1) a watershed loading
model, Hydrologic Simulation Program-Fortran (HSPF), developed for
each of the four primary subwatersheds in the Christina River Basin by
the U.S. Geological Survey (Senior and Koerkle 2003a, 2003b, 2003c,
2003d); (2) a CSO flow model, XP-Stormwater Management Model
(XP-SWMM), developed by the City of Wilmington; and (3) a
hydrodynamic (and receiving water) model developed using the
computational framework of the Environmental Fluid Dynamics Code
(EFDC) (Hamrick 1992). Development of inputs for these models
involved the analyses of historical water quality and stream flow data
to estimate point and nonpoint sources of nutrients.
Fecal coliform - The HSPF watershed models were used to calculate
the baseline and allocation loads for fecal coliform bacteria for the
TMDLs for the PA-listed waters. The models were calibrated over a
four-year period (October 1994 to October 1998) to include low and
high stream flow. Septic system loads and bacteria accumulation and
storage on different land uses were estimated and incorporated into
the models.
23
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SEDIMENT
Allocations:
Point sources
BACTERIA
SEDIMENT
Nonpoint sources
Implementation:
A reference watershed approach was used to estimate the necessary
sediment load reduction required.
The MS4 permits do not identify the boundaries of the stormwater
collection system contributing areas within each municipality.
Therefore, it is not possible to assign a bacteria or sediment wasteload
allocation (WLA) specific to the storm sewer collection areas within
each MS4 municipality. Because these systems have not yet been
delineated, the TMDL includes nonpoint source (NPS) loadings in the
WLA portion of the TMDL. It is anticipated that the state's stormwater
program will revise the WLA into the appropriate WLA and load
allocation (LA) as part of the stormwater permit reissuance; the
overall reductions in the TMDL will not change.
The City of Wilmington's CSOs are NPDES-permitted discharges that
currently have no permit limits; future permits will contain permit
limits and require reductions in loads discharged to the Christina River,
Little Mill Creek, and Brandywine Creek. The non-MS4 point source
permittee's allocations for fecal coliform, enterococci, and TSS are not
reduced from their permitted levels.
MS4s received allocations based on drainage areas of each
municipality. The area-weighted LAs were further allocated by the
land use distribution of each municipality. None of the non-MS4
NPDES permitted dischargers were required to reduce their present
TSS NPDES permit limits because available discharge monitoring
reports indicated that the average discharge of sediment from such
facilities was usually well below the permitted TSS concentrations.
The septic system loads of fecal coliform and enterococcus were
reduced in the models by eliminating failed systems. After
municipalities delineate their MS4 boundaries, the bacteria and
sediment loads associated with NPS may be separated from the WLA
and moved to the LA portion of the TMDL. The total allocations will
remain unchanged.
1994 CSO Control Policy: Wilmington selected the presumptive
approach to address its CSOs, which requires capture for treatment of
85 percent of the combined sewage flows and limiting CSO discharges
to less than an average of four to six events per year. (Guidance
defines the required capture as the elimination or the capture for
treatment of no less than 85 percent by volume of the combined
sewage collected in the combined sewer system (CSS) during
precipitation events on a system-wide, annual average basis.)
Implementation of best management practices (BMPs) in the affected
areas should achieve the loading reduction goals established in the
TMDLs. Substantial reductions in the amount of bacteria and sediment
reaching the streams can be made through the planning of riparian
buffer zones, contour strips, cover crops, or stormwater retention
techniques.
For the Delaware portion of the Christina River Basin, the Christina
Basin Clean Water Partnership has developed a Watershed Restoration
Action Strategy (WRAS), which is intended to provide a guideline for
future watershed protection and restoration actions (for example, by
including goals and objectives for decreasing bacteria and sediment
24
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loads). The WRAS, developed in June 2003, is also designed to
interconnect with EPA's earlier low-flow TMDL for the Christina Basin
and this high-flow TMDL.
• The TMDL also mentions other active watershed groups, as well as
various local and government organizations, that provide watershed
stewardship in the Christina River basin.
Cost: • Cost information is not available in the TMDL documentation.
References:
Hamrick, J.M. 1992. A Three-dimensional Environmental Fluid Dynamics Computer Code:
Theoretical and Computational Aspects. Special Report 317. The College of William and
Mary, Virginia Institute of Marine Science.
Senior and Koerkle. 2003a. Simulation ofStreamflow and Water Quality in the Brandywine Creek
Subbasin of the Christina River Basin, Pennsylvania and Delaware, 1994-98. U.S. Geological
Survey Water-Resources Investigations Report 02-4279.
Senior and Koerkle. 2003b. Simulation ofStreamflow and Water Quality in the White Clay Creek
Subbasin of the Christina River Basin, Pennsylvania and Delaware, 1994-98. U.S. Geological
Survey Water-Resources Investigations Report 03-4031.
Senior and Koerkle. 2003c. Simulation of Streamflow and Water Quality in the Red Clay Creek
Subbasin of the Christina River Basin, Pennsylvania and Delaware, 1994-98. U.S. Geological
Survey Water-Resources Investigations Report 03-4138.
Senior and Koerkle. 2003d. Simulation of Streamflow and Water Quality in the Christina River
Subbasin and Overview of Simulations in Other Subbasins of the Christina River Basin,
Pennsylvania and Delaware, 1994-98. U.S. Geological Survey Water-Resources
Investigations Report 03-4193.
U.S. EPA Region III. 7 September 2006. Total Maximum Daily Loads for Bacteria and Sediment in
the Christina River Basin Watershed, Pennsylvania, Delaware, and Maryland. Philadelphia,
PA. Available at
httD://www.eDa.aov/rea3waDd/tmdl/Da tmdl/ChristinaMeetinaTMPL/index.htm
25
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Wissahickon Creek
Stormwater Source TMDL (2003)
Pennsylvania, USEPA Region 3
TMDL at a Glance
Subbasin:
Watershed size:
Key beneficial uses:
Impaired by:
Pollutant(s):
Sources considered:
Point sources
NUTRIENTS
SEDIMENT
Nonpoint sources
NUTRIENTS
SEDIMENT
Model(s) used:
TMDL Web link:
TMDL Highlights
Affected water uses:
Wissahickon Creek basin
64 square miles
Trout stocking (maintenance of stocked trout from February 15 to July 31
and maintenance and propagation offish species and additional flora and
fauna indigenous to warmwater habitat)
Nutrients, low dissolved oxygen, siltation, chlorine, water/flow variability,
oil and grease, and pathogens. The TMDL states that sources of
impairments associated with water/flow variability and other habitat
alterations are related to those sources contributing to the nutrient and
siltation impairments. "Therefore, through implementation of [BMPs] to
address [the] nutrient and siltation TMDLs, these related impairments will
be addressed indirectly."
nutrients and sediment
NPDES permitted discharges range from single family to large
industrial and municipal wastewater treatment plants
• MS4s
Irrigated golf courses, areas with high concentrations of septic tanks
and/or history of septic tank failure, unimpeded cattle access to
streams, and low-level dams
None; because the entire watershed is considered an urbanized area
subject to MS4s, all sources of siltation (overland flow and streambank
erosion) are considered point sources.
Low-flow, steady-state model, EPA's Environmental Fluid Dynamics Code;
modified version of EPA's Water Quality Analysis Simulation Program;
reference watershed approach, which consisted of a modified application
of the Generalized Watershed Loading Function (GWLF) watershed model,
including a module to simulate streambank erosion; ArcView version of
GWLF, BasinSim with output for a Streambank Erosion Simulation Module.
http://www.epa.QOv/reQ3wapd/tmdl/pa tmdl/wissahickon/
index.htm
Trout stocking, aquatic life, water supply, and recreation
26
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Applicable WQS:
NUTRIENTS
SEDIMENT
Technical approach:
Key indicator(s)
NUTRIENTS
SEDIMENT
Source assessment
NUTRIENTS
SEDIMENT
Models
NUTRIENTS
There are no numeric water quality standards for nutrients or
sediment in Pennsylvania.
Based on analyses of 1998 and 2002 data, EPA determined that the
link between nutrient concentrations, dissolved oxygen (DO)
concentrations, and instream biological activity was a necessary
component of TMDL endpoint determination. Only DO has applicable
numeric criteria in Pennsylvania. The standards for DO are based on
levels required to support fish populations, and the critical period is
based on supporting the more stringent aquatic life use for trout
stocking. This period requires a minimum DO level of 5.0 mg/L and a
minimum daily average of 6.0 mg/L to support the aquatic life use for
trout stocking from February 15 through July 31. For the remainder of
the year, a minimum DO level of 4.0 mg/L and a minimum daily
average of 5.0 mg/L are required to support warmwater fish.
EPA used a reference watershed approach to develop the allowable
sediment loading rates.
Given the scientific knowledge available and the model processes that
describe the relationships of nutrients, carbonaceous oxygen demand
(CBOD), sediment oxygen demand, and their impact on DO, EPA
determined that the appropriate pollutants for the TMDL included
ammonia nitrogen (NH3-N), nitrate-nitrite nitrogen (NO3+NO2-N),
ortho phosphate (ortho PO4-P), and carbonaceous oxygen demand
(CBOD5).
Total suspended solids (TSS), converted to Ibs sediment/year
An analysis of 1998 and 2002 data indicated that during low-flow
periods, nutrient concentrations are dominated by point sources.
During the critical low-flow period, impacts from nonpoint sources
(NPS) are limited because storm runoff is not a factor during such dry
conditions.
An analysis of 1998 and 2002 data indicated during wet weather
conditions, the impact of point sources on the total siltation loads to
the streams is negligible. To assess the relative loads of sediment
from different land uses within municipal boundaries, EPA used land
use specific, unit area loadings. Urban and residential land uses in the
basin account for more than 50 percent of the total area and are
considered to be major contributors of sediment loads. However, the
largest contributors of sediment in the watershed are instream sources
attributed to streambank erosion. The siltation modeling report
estimated the load from streambank erosion and determined that the
cause of the flow variability (periodic high flows) that results in
streambank erosion is related to urban runoff and the sources of
impairments are MS4s.
A low-flow, steady-state model was used that included chemical and
biological processes associated with nutrient enriched and eutrophic
systems. Two models were used to simulate the hydrodynamics and
water quality: EPA's Environmental Fluid Dynamics Code (EFDC) was
used to simulate hydrodynamics, and a modified version of EPA's
Water Quality Analysis Simulation Program (WASPS) used the results
of the hydrodynamic model to simulate processes associated with
nutrients, DO, and biological activity.
27
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SEDIMENT
Allocations:
Point sources
NUTRIENTS
SEDIMENT
Nonpoint sources
NUTRIENTS
SEDIMENT
Implementation:
A reference watershed approach was used to develop a TMDL for
siltation, and the modeling framework consisted of a modified
application of the Generalized Watershed Loading Function (GWLF)
watershed model (Haith and Shoemaker 1987), including a module to
simulate streambank erosion. The ArcView version of the GWLF
(Evans et al 2001) was used to develop input and estimate sediment
loadings from overland runoff. Using the hydrology input parameters
from the AVGWLF model, BasinSim (Dai et al. 2000) was used to run
GWLF with model output for a Streambank Erosion Simulation Module.
This separate module estimated loadings from streambank erosion
using daily flows predicted by GWLF, site-specific information, and
process-based algorithms.
EPA established the wasteload allocations (WLAs) by reducing CBOD,
NH3-N, NO3+NO2-N, and ortho PO4-N loads from NPDES point sources
until daily average and minimum daily DO criteria were satisfied.
Nutrient WLAs for each point source were determined on a case-by-
case basis, with most reductions determined by local improvements
downstream from the point of discharge. Where dischargers were in
close proximity, sensitivity analyses were performed to ensure that
appropriate sources received reductions.
Sediment allocations began at the top of the watershed and continued
downstream to the mouth of the watershed. Total sediment loads
were based on unit-area loadings for each land use, and the
streambank erosion sediment load was distributed to each of the listed
segments based on the drainage area of each listed segment within
the appropriate subwatershed. Separate TMDL calculation approaches
and margin of safety assumptions were used to determine WLAs
associated with overland runoff and streambank erosion. Each MS4
permittee received a WLA based on the sediment loading from land
uses and streambank erosion within their municipal boundaries. The
MS4 WLAs for overland loads are allocated by landuse type, including
low-intensity residential, high-intensity residential, hay/pasture, row
crops, coniferous forest, mixed forest, deciduous forest, and
transitional.
NPS load reductions—through load allocations (LAs)—were considered
unnecessary for background loads. However, to address the
impairment in these stream segments, the TMDL recommends
implementation measures to address non-source related factors that
can result in biological improvements.
The upstream load from the three of the five subwatersheds received
LAs because these loads originated from sources outside the
demarcated watersheds. However, the percent load reduction
required in the LAs for NPS is 0.
The TMDL provides "equally protective" nutrient and sediment TMDLs
and WLAs based on several scenarios to provide implementation
flexibility.
Because instreambank erosion is the most significant contributor of
sediment in the watershed, "... reductions in the sediment entrained in
overland flow must be accompanied by substantial reductions in the
volume of water delivered to the stream in order to achieve the water
quality objectives of the TMDL. Efforts must also be taken to control
28
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MS4s
State-specific
opportunities
Cost:
References:
future potential sources of sediment and stormwater as new
construction and redevelopment occurs."
In Pennsylvania, Philadelphia is one of two cities covered under the
NPDES Phase I program, and 16 municipalities in the Wissahickon
watershed are required to have NPDES Phase II permits. The State
has developed a protocol that MS4s covered under the PA general
permit can adopt to satisfy the permit requirements. MS4s can also
choose to develop their own programs, but they must seek the
Pennsylvania Department of Environmental Protection's (PADEP)
approval.
MS4 permits could be issued in the future on a watershed basis to
improve stormwater management where multiple jurisdictions are
responsible for a single watershed, as is the case in Wissahickon
Creek, or where the approach can be specialized to focus on a
pollutant of concern to all jurisdictions, such as sediment.
Pennsylvania adopted a "comprehensive stormwater management
policy" on September 28, 2002, to more fully integrate post-
construction stormwater planning requirements and emphasize the use
of groundwater infiltration, as well as best management practices
(BMPs) that control the volume and rate of stormwater (see appendix
H of the TMDL for a copy of the policy).
Under Pennsylvania's "Stormwater Management Act of 1978" (Act
167), counties are required to develop stormwater control plans for
each watershed. A community must enact, administer, and enforce
stormwater ordinances within six months of PADEP approval of an Act
167 plan. After a community has enacted its stormwater ordinances,
the community may be eligible for state low interest loans to correct
existing stormwater drainage problems. An Act 167 plan has not yet
been prepared for the Wissahickon watershed.
PADEP has finalized a model ordinance for municipalities that operate
MS4s (available via the stormwater link at www.dep.state.pa.us).
Cost information is not available in the TMDL documentation.
Dai, T., R.L. Wetzel, Tyler R.L. Christensen and E.A. Lewis. 2000. BasinSim 1.0 A Windows-Based
Watershed Modeling Package User's Guide SRAMSOE #362 (computer program manual).
Virginia Institute of Marine Science, School of Marine Science, College of William & Mary,
Gloucester Point, VA. http://www.vims.edu/bio/vimsida/basinsim.html
Evans, B.M., S.A. Sheeder, K.J. Corrandi, and W.S. Brown. November 2001. AVGWLF Users Guide.
Environmental Resources Research Institute, Pennsylvania State University, University Park,
PA. (3) The following reference is not included in the references section of the TMDL, but is
referenced on p. 4-13:
Haith, D.A., and L.L. Shoemaker. 1987. Generalized Watershed Loading Functions for Streamflow
Nutrients. Water Resources Bulletin 23(3):471-478.
U.S. EPA Region III. October 9, 2003. Total Maximum Daily Load for Sediment and Nutrients:
Wissahickon Creek Watershed. Available at
httD://www.eDa.aov/rea3waDd/tmdl/Da tmdl/wissahickon/index.htm
29
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Harpeth River Watershed
Stormwater Source TMDL (2002)
Tennessee, EPA Region 4
TMDL at a Glance
Subbasin:
Watershed size:
Key beneficial uses:
Impaired by:
Pollutant(s):
Sources considered:
Model(s) used:
TMDL Web link:
TMDL Highlights
Affected water uses:
Applicable WQS:
Technical approach:
Allocations:
Harpeth River
863 square miles
Fish and aquatic life
Siltation and habitat alteration
Sediment
Point source - 23 wastewater treatment plants (WWTPs), 33 permitted
construction sites, and municipal separate storm sewer systems (MS4s)
(Phase I and II)
Nonpoint source - agriculture, roadways, and urban sources
Watershed Characterization System Sediment Tool
http://www.state.tn.us/environment/wpc/tmdl/approvedtmdl
/HarpSed07.pdf
Fish and aquatic life
Sediment (narrative) - protection offish and aquatic life, biological
integrity
Key indicator(s) - Sediment and total suspended solids (TSS)
Source assessment - The watershed characterization system (WCS)
sediment tool (v.2.1), an ArcView GIS-based program developed by
U.S. EPA Region IV, was used to determine the target average annual
sediment loading values for reference watersheds in Level IV
ecoregions, as well as the impaired watersheds. The sediment tool
uses CIS data, the Universal Soil Loss Equation (USLE), and sediment
delivery equations to estimate soil erosion and sediment delivery. The
sediment tool also can be used to evaluate the effects of changing land
uses and implementing various BMPs.
Point source - The wasteload allocation (WLA) for each of the 23
NPDES regulated municipal and industrial WWTPs was set equal to
their current NPDES permit limits for either TSS or turbidity. The WLA
for NPDES regulated construction sites and MS4s is calculated as the
average annual sediment load (Ibs/aere/year) for a given
30
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subwatershed, resulting in percent reductions ranging from about 33%
to 90% depending on the subwatershed.
Nonpoint source - The load allocation (LA) is calculated as the average
annual sediment load for a given subwatershed, resulting in similar
percent reductions. The LA includes NPDES Phase II MS4 discharges
because Phase II permits had not yet been issued when the TMDL was
developed.
Implementation: • Implementation of the LAs for nonpoint sources will be accomplished
within the framework of Tennessee's watershed approach. The
watershed approach is based on a five-year cycle and encompasses
planning, monitoring, and assessment and relies on participation at
the federal, state, local, and nongovernmental levels. The approach is
documented on the TDEC web site (see references).
• The Harpeth River Watershed Management Plan (TDEC 2002b)
describes the partnerships among government agencies and
stakeholder groups and the roles that each play in improving water
quality and reducing pollutant loading. The TMDL states that these
stakeholders "... should, at a minimum, be directed to: implement and
maintain conservation farming, including conservation tillage, contour
strips and no till farming; install grass buffer strips along streams;
reduce activities within riparian areas; and minimize road and bridge
construction impacts on streams."
In Tennessee, aquatic resource alteration permits are required for any
alteration of state waters not requiring a federal permit (TDEC 2000).
Monitoring will be guided by the results of a Harpeth River watershed
sediment study conducted by the Harpeth River Watershed Association
and the Cumberland River Compact.
Cost: • Cost information is not available in the TMDL documentation.
References:
Tennessee Department of Environment and Conservation (TDEC), Division of Water Pollution
Control; US EPA Region IV; and Tetra Tech, Inc. 10 May 2002a. Total Maximum Daily Load
(TMDL) for Siltation and Habitat Alteration in the Harpeth River Watershed (HUC
05130204), Cheatham, Davidson, Dickson, Hickman, Rutherford, and Williamson County,
Tennessee. Available at
http://www.state.tn.us/environment/wpc/tmdl/approvedtmdl/HarpSed07.pdf
TDEC. 2002b. Harpeth River Watershed Management Plan. Available at
httD://state.tn.us/environment/wDC/watershed/wsmDlans/harDeth/
TDEC. 2000. Aquatic Resource Alteration, Chapter 1220-4-7 (Revised).
TDEC. Watershed Management Approach web site. Available at
http://www.state.tn.us/environment/wpc/watershed/
31
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Pee Dee River Basin
Stormwater Source TMDL (2005)
South Carolina, USEPA Region 4
TMDL at a Glance
Pee Dee River Basin
Subbasin:
Watershed size:
Key beneficial uses:
Impaired by:
Pollutant(s):
Sources considered:
Model(s) used:
TMDL Web link:
TMDL Highlights
Affected water uses:
Applicable WQS:
Technical approach:
Pee Dee River Basin and Lynches River Basin
Pee Dee River Basin: 3,425 square miles, excluding the Lynches River and
Black River Basins; Lynches River Basin: 1,387 square miles
Primary contact recreation
Pathogens
Fecal coliform
Point source - Wastewater treatment plants, municipal separate storm
sewer systems (MS4s), and separated sewer systems (SSOs). Fecal
coliform sources associated with MS4s include leaking sewers, SSOs, pets,
and wildlife.
Nonpoint source - Wildlife (the large population of deer in the watersheds
may be a significant source of fecal coliform loading), agricultural
activities (land application of manure from animal (poultry) feeding
operations, uncovered animal waste stockpiles, cows allowed direct access
to creeks), failing onsite wastewater disposal systems (septic systems,
irrigation, and cesspools) and illicit discharges, and domesticated animals
Load Duration Curve
Final TMDL document not available electronically
Primary contact recreation
Not to exceed a geometric mean of 200 colony forming units (cfu)/100
mL based on five consecutive samples during any 30-day period, nor
shall more than 10 percent of the total samples during any 30-day
period exceed 400 cfu/100 mL.
Key indicator(s) - Fecal coliform (numeric)
Source assessment - Analyses were performed using fecal coliform
data and precipitation data from 1994 to 2002 to estimate the
relationship between rainfall and elevated fecal coliform bacteria loads
at 16 water quality monitoring stations. The estimated load included
loading from all sources including continuous point source discharges,
leaking sewer lines, MS4s, SSOs, failing on-site waste disposal
systems, land application fields, wildlife, pets, and livestock. The
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Allocations:
Implementation:
Cost:
References:
analysis and load duration curves for each monitoring station
demonstrate that exceedances at many of the stations are the result
of nonpoint source loading.
Model - The load duration curve (LDC) approach was used, which
incorporates the assimilative capacity of a waterbody as a function of
flow and allows for the maximum allowable loading to vary with flow
conditions. LDC analysis involves using measured or
estimated/modeled flow data, instream criteria, and
concentration/load data to assess flow conditions in which water
quality exceedances are occurring.
Point source - To estimate the wasteload allocation (WLA) for each
wastewater treatment plant (WWTP), the TMDL uses the permitted
average flow rate for each point source discharge and the water
quality criterion concentration. Because a WLA for each MS4 cannot
be calculated as an individual value, WLAs for MS4s are expressed as a
percent reduction goal derived from the LDC for nonpoint sources.
Where multiple monitoring stations were located within the same MS4
jurisdiction, the station with the highest percent reduction goal was
selected as the overall reduction requirement for the TMDL for each
station within the MS4 jurisdiction. A WLA percent reduction was not
calculated for NPDES permitted WWTPs because it was assumed that
the continuous dischargers are adequately regulated under existing
permits.
Nonpoint source - The nonpoint load reductions were estimated for
each monitoring station by calculating the difference between the
existing loading and the load duration curve. The difference is the
percent reduction, and the hydrologic condition class (moist, mid-
range, and dry) with the largest percent reduction selected as the
critical condition and the overall percent reduction goal for the LA.
The LDC approach can be used to identify appropriate measures for
implementation.
Cost information is not available in the TMDL documentation.
U.S. EPA Region 4. September 2005. Total Maximum Daily Loads for Fecal Coliform for Hills Creek,
Lynches River, North and South Branch of Wildcat Creek, Flat Creek, Turkey Creek, Nasty
Branch, Gulley Branch, Smith Swamp, Little Pee Dee River, Maple Swamp, White Oak Creek,
and Chinners Swamp of the Pee Dee River Basin, South Carolina. Atlanta, GA.
33
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Lake Michigan Shoreline
Stormwater Source TMDL (2004)
Indiana, USEPA Region 5
TMDL at a Glance
Subbasin:
Watershed size:
Key beneficial uses:
Impaired by:
Pollutant(s):
Sources considered:
Model(s) used:
TMDL Web link:
TMDL Highlights
Affected water uses:
Applicable WQS:
Technical approach:
Lake Michigan shoreline in Lake, Porter, and La Porte Counties
536 square miles
Swimming
Pathogens
Pathogens
Point source - None; CSO's upstream, but not addressed in TMDL
Nonpoint source - seven tributaries; residential septic systems from 11
locations; wildlife (deer, raccoons, and seagulls); swimmers, beach
restroom facilities, beach sands, and algae at six major beach locations;
and boaters at three marinas
Environmental Fluid Dynamics Code
httD://www.in.qov/idem/Droqrams/water/tmdl/finalrDt/lkmichtmdl.doc
Swimming
E.coli (numeric)
Key indicator(s) - E.coli
Source assessment - The existing load from the tributaries was
calculated by estimating the E. coli load from each tributary during the
1999 beach season. The estimated load from swimmers at beaches
was based on estimates of the number of people visiting the lakeshore
beaches each day and 0.14 grams as the mean amount of fecal
material shed per swimmer (Gerba 2000). Wildlife loads were
calculated by estimating the wildlife population and the amount off.
coli contributed by each organism based on literature sources. Best
professional judgment was used to calculate the load from boating
activity by estimating the number of boaters and the percent of
generated E. coli waste reaching the water (10 percent). Estimates of
the loads from residential septic systems were based on U.S. census
data and literature values for average daily discharge, septic effluent
E. coli concentration, and septic failure rates.
Model - Environmental Fluid Dynamics Code or EFDC (Hamrick 1992),
a hydrodynamic fate and transport model, was used to establish
baseline conditions and three allocation scenarios. The model has
34
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three main components: (a) the E. coli loads, (b) water motion from
physical transport, and (c) kinetic reactions that affect the fate of E
coli.
Allocations: • Nonpoint source only - The seven tributaries were allocated percent
reductions in E. coli load (counts/recreation season) ranging from 0 to
90.5%. However, the TMDL does not address the upstream sources
transported through these tributaries. At the time the report was
published, TMDLs were being developed for several tributaries. Two of
the six beaches were allocated 80% reductions. The TMDL did not
allocate reductions for any of the other nonpoint sources (the other
four beaches, residential septic sources, boats, and wildlife).
Implementation: • The TMDL documents several activities that should be implemented,
including, including: (1) implementing tributary TMDLs to achieve
water quality standards, including efforts to reduce E. coli loads
associated with combined sewer overflows, septic systems, and
livestock; (2) continuing efforts to reduce loads from septic systems
through public education and maintenance and replacement programs;
and (3) continuing efforts to reduce E. coli loads associated with boat
pumpouts.
Cost: • Cost information is not available in the TMDL documentation.
References:
Gerba, C. 2000. Assessment of Enteric Pathogen Shedding by Bathers during Recreational Activity
and its Impact on Water Quality. Quantitative Microbiology. 2:55-68.
Hamrick, J.M. 1992. A Three-dimensional Environmental Fluid Dynamic Computer Code:
Theoretical and Computational Aspects. SRAMSOE #317, Virginia Institute of Marine
Science, The College of William and Mary, Gloucester Point, VA.
Tetra Tech, Inc., for Indiana Department of Management (IDEM). August 2004. Lake Michigan
Shoreline TMDL for E. coli Bacteria. Available at
htto: //www. in.aov/idem/Droarams/water/tmdl/finalrDt/l kmichtmdl.doc
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Lower Cuyahoga River
Stormwater Source TMDL (2003)
Ohio, USEPA Region 5
TMDL at a Glance
Subbasin:
Watershed size:
Key beneficial uses:
Impaired by:
Pollutant(s):
Sources considered:
Model(s) used:
TMDL Web link:
TMDL Highlights
Affected water uses:
Applicable WQS:
Lake Erie Basin
813 square miles (Cuyahoga River Basin)
Aquatic life, recreation activities, and public water supply; part of the
Cuyahoga River is a designated state scenic river and several stream
segments within the basin have been designated as state resource waters.
Organic and nutrient enrichment, bacteria, toxicity, low instream dissolved
oxygen, flow alteration, degraded habitats, and sedimentation
Phosphorus, nutrients, fecal coliform
Point sources - Wastewater treatment plants, municipal separate
storm sewer systems (MS4s), and combined sewer overflows (CSOs)
Nonpoint sources - unregulated runoff over land, septic systems, reservoir
and diversions, groundwater
Load Duration Curve, Streamflow Hydrograph Separation and Analysis,
Soil and Water Assessment Tool, Multiple Discharge version of the
Simplified Method Program, XP Stormwater Management Model, Water
Quality Analysis Simulation Program
http://www.epa.state.oh.us/dsw/tmdl/Cuvahoqa lower
final report.pdf
Cold water habitat, warmwater habitat (WWH), modified warmwater
habitat, and limited resource water aquatic life uses; primary and
secondary contact recreation; and public water supply.
Narrative - Free from suspended solids and other substances that
enter the waters as a result of human activity and that will settle to
form objectionable sludge deposits, or that will adversely affect aquatic
life.
Numeric - Dissolved oxygen (DO): Instantaneous minimum = 4.0
(WWH) mg/L (Cuyahoga River Ship Cannel DO instantaneous
minimum = 1.5 mg/L); 24-hour average = 5.0 (WWH) mg/L. Fecal
coliform bacteria: Geometric mean = 1,000 (most probable number or
mpn); maximum = 2,000 mpn. Ecoregion biological criteria also
apply.
36
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Technical approach:
Key indicator(s)
Source assessment
Allocations:
Implementation:
Total phosphorus, fecal coliform, dissolved oxygen, biological and
habitat indices
Nonpoint sources - The existing load from nonpoint source (NPS)
runoff was not calculated—it was estimated as the difference between
the total known instream load and the sum of the other input loads
(including loss through the assimilative capacity of the river). The
loads from septic systems were calculated based on a model
developed by Mandel (1993) that uses system characterization by
performance type and location and the number of systems. This
method is also used in the Generalized Watershed Loading Functions
model.
Point sources - A daily load value per point source discharger was
calculated by multiplying the daily flow and daily concentration with a
conversion factor. To estimate the load from CSOs, the City of Akron
used Stormwater Management Tool (XP-SWMM) and Water Quality
Analysis Simulation Program (WASP) to determine the system loads
and impacts to the stream water quality.
Groundwater - The portion of the stream flow due to groundwater was
calculated using the USGS Streamflow Hydrograph Separation and
Analysis (HYSEP) model, a computer program that can be used to
separate a streamflow hydrograph into baseflow and surface-runoff
components (USGS 1996).
Future growth - An area-weighted approach based on the average of
each county's expected growth was used to factor future growth into
the TMDL. This information was based on U.S. Census Bureau data
and weighted by the land area of the county within the Cuyahoga
watershed.
Instream loss - The instream loss term due to assimilative capacity
was estimated as the median for the daily total observed load in the
stream minus the daily total known input load for days without runoff.
Model - The load duration curve (LDC) approach was used, which
identifies the allowable loads under the full range of flow conditions
and provides a framework for comparing observed water quality data
to the allowable load to evaluate when exceedances occur.
Point sources - The CSO total phosphorus and fecal coliform
allocations were determined based on the long-term control plans
(LTCPs) for Akron and Cleveland. Specifically, each city's estimated
overflow volume after LTCP strategy implementation was multiplied by
an expected CSO-specific concentration based on the proposed control
technologies for the various CSOs. A procedure was developed to
relate the CSO overflow events to the LDC method.
Nonpoint sources - Land cover was an important component for
calculating both the total phosphorus and fecal coliform nonpoint
source existing loads and allocations. The necessary runoff reductions
were based on the additional load reductions needed on wet weather
days after incorporating all other load reductions. The CIS-based Soil
and Water Assessment Tool (SWAT) was used to support the allocation
analysis. SWAT uses digital elevation information and other
information to define watersheds so that land cover, soil data, and
other information layers can be analyzed for each watershed.
Habitat goals - Physical habitats within the Cuyahoga River were
evaluated using the Qualitative Habitat Evaluation Index (QHEI)
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developed for the Ohio EPA for streams and rivers in Ohio. The QHEI
can be used as a guide to direct restoration efforts for habitat and
sediment load reductions and provides a monitoring tool to measure
progress towards habitat and sediment load goals.
Wetland protection - The TMDL recommends that no new permits be
issued that impact Category 2 and 3 wetlands in the Lower Cuyahoga
River TMDL area. In addition, the TMDL states that all permits issued
for impacts to Category 1 wetlands should ensure that mitigation is
conducted on site if possible and at a minimum within the watershed
area. Finally, if mitigation cannot be conducted on site or within the
watershed area, then the TMDL states that a permit should not be
issued for the proposed project.
Riparian protection - Two mechanisms are proposed in the TMDL—(1)
the passage of stream setback ordinances similar to the one passed in
Summit County, and (2) the Cuyahoga Valley National Park's riverbank
stabilization plan to address erosion threats to important park
infrastructure (in development when the TMDL was written).
Stakeholders - The TMDL states that one of the areas in which the
Lower Cuyahoga River TMDL area excels "... is the formation of
watershed groups promoting awareness, stewardship, and education."
The TMDL mentions key partners, including the Cuyahoga Valley
National Park, county park programs, and watershed-based groups
located within the Lower Cuyahoga River basin.
Cost: • Cost information is not available in the TMDL documentation.
References:
Mandel, R. 1993. The Impact of Septic Systems on Surface Water Quality. Unpublished M.S.
dissertation. School of Civil and Environmental Engineering, Cornell University. Ithaca, NY.
Ohio Environmental Protection Agency, Division of Surface Water. September 2003. Total Maximum
Daily Loads for the Lower Cuyahoga River. Available at
http://www.epa.state.oh.us/dsw/tmdl/Cuyahoga lower final report.pdf
U.S. Geological Survey (USGS). 1996. HYSEP: A Computer Program for Streamflow Hydrograph
Separation and Analysis. Water Resource Investigations Report 96-4040. Lemoyne, PA.
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Middle Rio Grande River
Stormwater Source TMDL (2002)
New Mexico, USEPA Region 6
TMDL at a Glance
Subbasin:
Watershed size:
Key beneficial uses:
Impaired by:
Pollutant(s):
Sources considered:
Model(s) used:
TMDL Web link:
Rio Grande River Basin
3,204 square miles
State uses affected: limited warmwater fishery, secondary contact
recreation, and irrigation. The two segments for which this TMDL is
written also have the designated uses of livestock watering and wildlife
habitat. Tribal uses affected: primary contact ceremonial, primary contact
recreation, secondary contact recreation, warmwater fishery, agricultural
water supply.
Pathogens
Fecal coliform
Point source - Phase 1; City of Albuquerque municipal separate storm
sewer system (MS4) and other individual National Pollutant Discharge
Elimination System (NPDES) permittees, including four wastewater
treatment plants (WWTPs) and four other discreet conveyances
Nonpoint source - Livestock rearing and operations, wildlife, migratory
birds, domestic animals and pets
Hydrotech® computer program and Mass Balance
http://www.nmenv.state.nm.us/swgb/Middle Rio Grande-
Fecal Coliform TMDL-Mav2002.pdf
TMDL Highlights
Affected water uses:
Applicable WQS:
Technical approach:
Warmwater fishery and limited warmwater fishery, primary and
secondary contact recreation, primary contact ceremonial, and
irrigation.
The Middle Rio Grande River is divided into two segments. The water
quality criteria (WQC) for one of the segments states that the monthly
geometric mean of fecal coliform bacteria shall not exceed 1,000/100
mL, and no single sample shall exceed 2,000/100 mL. The WQC for
the other segment states that the monthly geometric mean of fecal
coliform bacteria shall not exceed 200/100 mL, and no single sample
shall exceed 400/100 mL. The Pueblo of Sandia has tribal surface
water quality standards and designated uses. For example, from April
to September 30, the primary contact recreation standard is a
geometric mean maximum of 100 colonies/100 mL based on a
minimum of five samples taken over a maximum of 30 days and a
single sample maximum of 200 colonies/100 mL. Other tribal
standards apply for other uses.
Key indicator(s) - Fecal coliform (numeric)
Source assessment - The main transport of fecal coliform and the
focus of this document are Stormwater conveyances. During the
annual monsoon rain season (May through September), the four non-
wastewater conveyance systems collect and transport fecal coliform
from various sources in the watershed to the river. All exceedances
based on the 1999 monitoring data were observed after summer rain
39
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Allocations:
Implementation:
Cost:
References:
events. The following sources do not appear to be large contributors
to the fecal coliform exceedances: failing or ill-sited septic systems,
leaks in sanitary sewer systems, overflows from surcharged sanitary
sewers, illicit connections of sanitary sewers to storm sewer collection
systems, and unidentified broken sewer lines.
Model - A Hydrotech® computer program was used to calculate the
critical low flow value between May and September. The allocations
were determined using a simple calculation based on the water quality
criterion and applicable flows.
Point source - Numeric targets for four stormwater conveyances were
established in this TMDL and assigned a wasteload allocation (WLA).
Nonpoint source - The load allocations (LAs) were calculated by
determining the WLA for a particular arroyo or drain based on the
mean annual maximum flow and the water quality criterion and then
by subtracting that WLA from the corresponding loading capacity.
The implementation approaches section describes several conventional
best management practices (BMPs) and their estimated costs.
There are other conveyances to the Middle Rio Grande in addition to
the four addressed in this TMDL, and the state hopes that the Phase II
Stormwater Management Program will address all of them.
The TMDL mentions the New Mexico nonpoint source (NPS) task force,
comprised of government, tribes and pueblos, soil and water
conservation districts, industry, and environmental organizations. This
task force was created to review Clean Water Act Section 319
proposals and to provide information to stakeholders and the public
about NPS issues.
Cost information is not available in the TMDL documentation.
New Mexico Environment Department, Surface Water Quality Bureau. May 2002. Middle Rio Grande
Total Maximum Daily Load (TMDL) for Fecal Coliform. Available at
http://www.nmenv.state.nm.us/swgb/Middle Rio Grande-Fecal Coliform TMDL-
Mav2002.pdf
40
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Mantua Reservoir
Stormwater Source TMDL (2003)
Utah, USEPA Region 8
TMDL at a Glance
Subbasin:
Watershed size:
Key beneficial uses:
Impaired by:
Pollutant(s):
Sources considered:
Model(s) used:
TMDL Web link:
TMDL Highlights
Affected water uses:
Applicable WQS:
Mantua Reservoir watershed
The watershed size is not included in the TMDL, and the surface area of
the reservoir is 554 acres.
Secondary contact recreation; coldwater species of game fish and other
coldwater aquatic life, including the necessary aquatic organisms in their
food chain; and agricultural uses, including irrigation of crops and stock
watering
Nutrients
Total phosphorus (TP), dissolved oxygen (DO), and pH
Point source - Mantua fish hatchery (Utah Pollution Discharge Elimination
System permit) and a pump station installed by Brigham City to pump
agricultural runoff water
Nonpoint source - Agriculture and background due to spring flow
Carlson's Trophic State Index, steady-state mass balance, chlorophyll a
and Secchi depth response model
http://www.wateraualitv.utah.gov/TMDL/Mantua Reservoir TM
DL.pdf
Secondary contact recreation; and coldwater species of game fish and
other coldwater aquatic life, including the necessary aquatic organisms
in their food chain
The following numeric criteria apply to the coldwater fishery beneficial
use: 6.5-9.0 pH; minimum 6.5 mg DO/L (30-day average), 9.5/5.0
mg DO/L (7-day average), and 8.0/4.0 mg DO/L (1-day average); and
total phosphorus (indicator) 0.5 mg TP/L for rivers and streams and
0.025 mg/L for lakes and reservoirs. Note: For the DO criteria, the
first number (e.g., 9.5 in 9.5/5.0 above) applies when early life stages
are present; the second number (e.g., 5.0) applies when all other life
stages are present.
The TMDL targets are to achieve: (1) the applicable water quality
criteria for DO in the upper 50% of the reservoir's water column, (2)
41
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Technical approach:
Allocations:
Implementation:
Cost:
the pH standard of 6.5-9.0 for at least 90% of the in-lake
measurements, and (3) 25 ug TP/L as the in-lake total phosphorus
concentration as an annual average of surface values.
Key indicator(s) - Total phosphorus (numeric)
Source assessment - The Mantua fish hatchery is the only permitted
point source in the watershed, which contributes 29% of the TP load.
However, because phosphorus is listed as a pollution "indicator" in the
water quality standards, the hatchery permit did not include permit
limits for phosphorus, only sediment. There is an additional point
source—a pump station installed by Brigham City to pump agricultural
runoff water that contributes 25% of the TP load. The other sources
include other agriculture (15% of the TP load) and background due to
spring flow (31%).
Models - A steady-state mass balance (phosphorus reduction
response) model—as described by Vollenweider (1976), Reckhow
(1979), and EPA (1983)—was used to estimate the inflow TP load
reduction required to meet the mean annual in-lake TP concentration
of 0.025 mg/L. The Carlson Trophic State Index (TSI) (Carlson 1977)
and a chlorophyll a and Secchi depth response model (Carlson 1977)
were used to predict the expected trophic condition given a 0.025
mg/L TP target concentration.
Point source - The TP loads were allocated to point sources based on
conservative, best professional judgment that the individual reductions
could be met. The two point sources—the pump station and Mantua
fish hatchery—received 100 and 15 percent reductions, respectively.
Nonpoint source - The two nonpoint sources—the Box Elder Creek
diversion and Bunderson Spring/Dam Creek—each received 20 percent
reductions.
The reservoir will continue to be monitored on a biannual basis to
track changes in trophic state.
Point sources - The agricultural pump station is no longer a source of
TP—the water was diverted to create a wetland to mitigate for a
highway project. In addition, the fish hatchery has changed its
feeding practices from a low-efficiency sinking feed to a high-
efficiency, low-phosphorus, floating feed. However, the document
states that the Mantua fish hatchery should clean the sedimentation
basin at the lower end of the hatchery on an annual basis. A
diagnostic and feasibility report or clean lakes study (Loveless 1998)
provided several other suggestions for additional activities to restore
the reservoir using agricultural and aquacultural best management
practices (BMPs).
Nonpoint sources - In addition to annually reconstructing and
maintaining the existing sediment retention basin located upstream
from the Box Elder Creek diversion, the TMDL lists several other BMPs
that could reduce TP loads from nonpoint sources.
Cost information is not available in the TMDL documentation.
References:
Carlson, R.E. 1977. A Trophic State Index for Lakes. Limnol. Oceanogr. 22(2):361-9.
42
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Loveless, R.M. 1998. Diagnostic and Feasibility Report on Mantua Reservoir. Mountainlands
Association of Governments, Provo, Utah.
Reckhow, K.H. 1979. Quantitative Techniques for the Assessment of Lake Quality. U.S. EPA Office
of Water Planning and Standards, Washington DC. EPA 440/5-79-015.
U.S. EPA. 1983. Technical Guidance Manual for Performing Wasteload Allocations. Book IV: Lakes
and Impoundments. Washington, DC. EPA 44/4-84-019.
Utah Department of Environmental Quality, Division of Water Quality, TMDL Section. 23 May 2003.
Mantua Reservoir Total Maximum Daily Load (TMDL). Available at
http://www.waterquality.utah.gov/TMDL/Mantua Reservoir TMDL.pdf
Vollenweider, R.A. 1976. Advances in Defining Critical Loading Levels for Phosphorus in Lake
Eutrophication. Mem. Inst. Ital. Idrobiol. 33:53-83.
43
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Los Angeles River Watershed
Stormwater Source TMDL (2005)
California, USEPA Region 9
TMDL at a Glance
Subbasin:
Watershed size:
Key beneficial uses:
Impaired by:
Pollutant(s):
Sources considered:
Model(s) used:
TMDL Web link:
Los Angeles River
834 square miles
Aquatic life and water supply
Metals
Cadmium (Cd), copper (Cu), lead (Pb), zinc (Zn), and selenium (Se)
Point sources - Wastewater effluent from the Tillman, Los Angeles-
Glendale, and Burbank treatment plants, as well as an estimated 1,600
other permittees in the Los Angeles River watershed, including: other
wastewater treatment plants (WWTPs), municipal Stormwater (3
facilities—two municipal separate storm sewer systems (MS4s) and
Caltrans), industrial-related Stormwater, construction-related Stormwater,
major individual facilities (3, including the Pacific Terminals LLC Tank
Farm, Boeing Company Santa Susana Field Lab, and Metropolitan Transit
Authority), minor individual facilities, and general discharges
Nonpoint sources - Open space and direct atmospheric deposition
Environmental Fluid Dynamics Code 1-D, Water Quality Analysis
Simulation Program, Loading Simulation Program in C++, Load Duration
Curve
http://www.swrcb.ca.QOv/rwqcb4/html/meetings/tmdl/tmdl ws los
anqeles.html
TMDL Highlights
Affected water uses:
Applicable WQS:
Aquatic life (i.e., wildlife habitat; warm freshwater habitat; rare,
threatened, or endangered species; wetland habitat; and marine
habitat) and water supply (i.e., groundwater recharge)
Narrative - Toxic substances shall not be present at levels that will
bioaccumulate in aquatic life resources to levels harmful to aquatic life
or human health
Numeric - The numeric targets in this TMDL are based on the water
quality objectives in the California Toxics Rule (CTR). The CTR
establishes freshwater, acute and chronic, hardness-dependent aquatic
life criteria for Cd, Cu, Pb, Zn, and Se. The CTR values for Cd, Cu, Pb,
and Zn are based on the dissolved fraction and are hardness
dependent, and the freshwater CTR standard for Se is based on the
total recoverable metals concentration.
Separate targets are developed for dry and wet weather because
hardness values and flow conditions in the Los Angeles River and
tributaries vary during dry and wet weather.
44
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Technical approach:
Allocations:
Implementation:
Key indicator(s) - Copper, lead, zinc, cadmium, and selenium
(narrative and numeric)
Source assessment - During dry weather, most of the flow in the Los
Angeles River is comprised of wastewater effluent from the Tillman,
Los Angeles-Glendale, and Burbank treatment plants. During the dry
season, wastewater treatment plant (WWTP) mean monthly discharges
range from 70 to 100 percent of the monthly average flow. In
contrast, in months with rain events, WWTP monthly average
discharges equaled less than 20 percent of the monthly average flow.
The sources of Se are not understood, and additional study is required
to determine whether the Se contributions are from natural or
background sources.
Models - Two different hydrodynamic and water quality models were
used to calculate the existing load during dry and wet weather
conditions. The Environmental Fluid Dynamics Code 1-D (EFDC1D)
was used to model the hydrodynamic characteristics of the Los
Angeles River and its tributaries during dry weather. EFDC1D was
linked to the Water Quality Analysis Simulation Program (WASPS) to
simulate water quality within the Los Angeles River. U.S. EPA's
Loading Simulation Program in C++ (LSPC) was used to simulate the
hydrologic processes and pollutant loading from the Los Angeles River
watershed during wet weather over a 12-year period. In addition, load
duration curves were used to establish the wet weather loading
capacities for Cd, Cu, Pb, and Zn.
TMDLs were developed for wet and dry conditions because of the
variability in flows, water hardness, sources, and relative magnitude of
loadings between these conditions. Wet-weather targets are
developed for storm conditions based on acute criteria because it
would be inappropriate to apply criteria based on long-term exposure
to storms that are generally short-term and episodic in nature. Wet
and/or dry weather allocations for each metal were determined based
on available water quality data.
Point sources - "Grouped" dry and wet weather wasteload allocations
(WLAs) were established for the two MS4 permits and the Caltrans
permit. The loadings associated with indirect air deposition are
included in the wet weather stormwater WLAs. The watershed is
divided into six subwatersheds with jurisdictional groups assigned to
each subwatershed. Each municipality and permittee will be
responsible for the WLAs shared by their jurisdictional group, and will
not necessarily be given a specific allocation for the land uses under
their jurisdiction.
Nonpoint sources - Mass-based wet and dry weather LAs were
calculated for open space and direct air deposition. "Open space"
refers to open space that contributes metals directly to the river and
not through the storm drain system (about 200 square miles).
The wet and dry weather models should provide useful in evaluating
management scenarios to help achieve load reductions in TMDL
implementation. In addition, a watershed approach is implemented in
this TMDL; that is, metals allocations are developed for upstream
reaches and tributaries that drain to impaired reaches.
This TMDL includes an implementation plan. In addition, the
monitoring section includes several components (the entities
responsible for implementing each component are in parentheses):
45
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ambient monitoring (MS4s and Caltrans), compliance assessment
monitoring (Tillman, LA-Glendale, and Burbank WWTPs), and special
studies (no entities specified).
Los Angeles has an agreement between 18 municipalities to implement
the stormwater regulations jointly.
Cost: • Cost information is not available in the TMDL documentation.
However, this TMDL includes a cost analysis based on a potential
phased implementation strategy that involves combining structural
and non-structural BMPs. The cost analysis focuses on compliance
with the grouped WLA for MS4 and Caltrans stormwater permittees in
the urban areas of the watershed and includes a cost analysis of street
sweeping (a non-structural BMP), infiltration trenches and sand filters
(structural BMPs), as well as the results of a region-wide cost study.
References:
U.S. EPA Region 9 and California Regional Water Quality Control Board (CRWQCB) Los Angeles
Region. June 2005. Total Maximum Daily Loads for Metals: Los Angeles River and
Tributaries. Available at
httD://www.swrcb.ca.QOv/rwacb4/html/meetinqs/tmdl/tmdl ws los anqeles.html
46
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San Diego Creek and Newport Bay
Stormwater Source TMDL (1999)
California, USEPA Region 9
TMDL at a Glance
Subbasin:
Watershed size:
Key beneficial uses:
Impaired by:
Pollutant(s):
Sources considered:
Model(s) used:
TMDL Web link:
Central Orange County in the southwest corner of the Santa Ana River
Basin
154 square miles
Groundwater recharge; navigation; water contact and non-contact
recreation; water non-contact recreation; commercial and sport fishing;
warm freshwater habitat; preservation of biological habitats of special
significance; wildlife habitat; rare, threatened, or endangered species;
spawning, reproduction, and development; marine habitat; shellfishing
harvesting; and estuarine habitat
Nutrients
Phosphorus and nitrogen
Point source - Industrial permits; MS4 (Orange County); Individual
Permits include permit requirements for nurseries and other NPDES
permittees. There are three large nurseries and numerous, smaller
nurseries. Other point sources include those with waste discharge
requirements and specific effluent limits for nitrogen compounds; and
Stormwater sources without specific numeric effluent limits for nutrients.
Nonpoint source - The nonpoint sources are mainly agricultural. Other
nonpoint sources include open space, particularly during storm events;
atmospheric deposition; unregulated nurseries; shallow groundwater that
contributes to base flows in storm channels and may exchange with the
saltwater in Newport Bay; and nutrients stored in plant biomass and bay
sediments that may be resuspended into the water column.
Mass Balance
http://www.epa.QOv/owow/tmdl/examples/nutrients/ca
sdnbav.pdf
TMDL Highlights
Affected water uses:
Applicable WQS:
Technical approach:
The beneficial uses listed above are affected in one or more of the
following waterbodies—upper and lower Newport Bay, San Diego Creek
(divided into two reaches), or tributaries to San Diego Creek
Narrative - Separate narrative standards exist for algae and dissolved
oxygen in enclosed bays and estuaries (Newport Bay) and inland
surface waters (San Diego Creek and tributaries).
Numeric - Reach 1 in San Diego Creek has a 13 mg/L total inorganic
nitrogen (TIN) water quality objective, and reach 2 has a 5 mg/L TIN
objective. There are no numeric water quality objectives for
phosphorus on San Diego Creek.
Key indicator(s) - Total phosphorus (TP) and total nitrogen (TN)
Source assessment - Several studies determined that about 80% of
the nitrate-nitrogen loading to Newport Bay was from the Peters
Canyon Wash, the main tributary to San Diego. San Diego Creek
contributes the vast majority (80%) of the TP load to Newport Bay.
Studies also indicated that increases in particulate levels (sediment)
47
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Allocations:
Implementation:
Cost:
and TP levels are closely related. Data were lacking regarding the
nutrient load contribution of shallow groundwater to base flows in
storm channels, which may exchange with the saltwater in Newport
Bay. The amount of nutrients stored in plant biomass and bay
sediments that can be resuspended into the water column was another
unknown.
TMDL endpoints - The total phosphorus TMDL is based on a 50%
reduction in current phosphorus loading to Newport Bay, and the total
nitrogen TMDL is based on a 50% reduction in the current low-flow
loading of TN to Newport Bay. The California Regional Water Quality
Control Board (Regional Board) also amended its Santa Ana Basin Plan
to require a 50% reduction in sediment loading to Newport Bay.
Model - Analyses based on flow rates and the applicable standards or
targets were used to estimate loads and allocations.
Point source - The point sources with TN wasteload allocations (WLAs)
include urban runoff and other NPDES discharges, and the point
sources with TP WLAs include urban areas and construction sites. EPA
would normally establish individual WLAs for each NPDES discharger,
but did not do so because the Regional Board was scheduled to adopt
specific WLAs for individual NDPES dischargers in April 1998.
Nonpoint source - The TN load allocations (LAs) include nurseries,
agricultural discharges, and undefined sources. The TP LAs include
agricultural land and open space.
Because Total Inorganic Nitrogen (TIN) levels are elevated throughout
the year, the TMDLs include allocations that apply during the wet and
dry seasons. However, wet season allocations only apply during non-
storm events, since exceedances of the standard are not observed
when flow rates are above 50 cubic feet per second.
The Regional Board's TMDL and associated Basin Plan provisions dated
December 9, 1997, along with subsequent modifications dated January
23, 1998, and March 6, 1998, describe the following implementation
activities:
- issuing waste discharge requirements to currently unregulated
nurseries greater than 5 acres and with discharges that contain
greater than 1 mg TIN/L;
revising existing waste discharge requirements for currently
regulated nursery operations;
- revising existing NPDES permits for which discharges of
nutrients exceed 1 mg TIN/L;
requiring the development of nutrient management plans for all
agricultural operations not regulated by waste discharge
requirements; and
- requiring that the co-permittees of the stormwater permit
submit an analysis of best management practices (BMPs) that
will be implemented to achieve the urban runoff targets.
In addition to nutrient reductions, the loading capacity of Newport Bay
was expected to increase with implementation of proposed dredging of
sedimentation basins in upper Newport Bay. This project would
increase tidal flushing of upper Newport Bay, diluting the nutrient
inputs from the San Diego Creek watershed and other tributaries.
Cost information is not available in the TMDL documentation.
48
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References:
California Regional Water Quality Control Board, Santa Ana Region. 1997. Resolution No. 97-77.
Amendment to the Santa Ana Region Basin Plan.
California Regional Water Quality Control Board, Santa Ana Region. 1997. Staff Report on the
Nutrient Total Maximum Daily Load for Newport Bay/San Diego Creek.
U.S. EPA Region 9. Total Maximum Daily Loads for Nutrients: San Diego Creek and Newport Bay,
California. Available at http://www.epa.Qov/owow/trndl/examples/nutrients/ca sdnbav.pdf
49
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Chester Creek, University Lake, and
Westchester Lagoon
Stormwater Source TMDL (2005)
Alaska, USEPA Region 10
TMDL at a Glance
Subbasin:
Watershed size:
Key beneficial uses:
Impaired by:
Pollutant(s):
Sources considered:
Model(s) used:
TMDL Web link:
TMDL Highlights
Affected water uses:
Applicable WQS:
Technical approach:
Not listed
30 square miles
Drinking, culinary, and food processing water supply
Pathogens
Fecal coliform
Point sources - Municipal separate storm sewer systems (MS4s) and
the sources associated with various types of land cover within the MS4
boundaries
Nonpoint sources - Domestic pets, waterfowl, and wildlife, septic systems,
indigent people living near creeks, leaking sewer lines, and natural
background
Stormwater Management Model
http://www.dec.state.ak.us/water/tmdl/Ddfs/chestercrwatershedTMDLEPA
Final.pdf
Drinking, culinary, and food processing water supply; water
recreation; and growth and propagation offish, shellfish, and other
aquatic life, and wildlife
The fecal coliform criteria for drinking, culinary, and food processing
water supply states that in a 30-day period, the geometric mean may
not exceed 20 FC/100 ml, and not more than 10 percent of the
samples may exceed 40 FC/100 ml.
Key indicator - Fecal coliform
Source assessment - The largest and most frequent exceedances of
the criteria occur during summer months, likely due to increased
Stormwater runoff. Areas with the highest fecal coliform loading rates
tended to be residential land uses with a high degree of
imperviousness and located close to the stream. In a 2003 report on
fecal coliform sources and transport processes, the Municipality of
Anchorage stated that the likely sources with these land uses are
warm-blooded animals, including domestic pets (particularly cats and
dogs) and wild animals.
Model - The Stormwater Management Model (SWMM, Huber and
Dickinson 2001) was selected to estimate existing and potential future
fecal coliform counts in the watershed. SWMM simulates the quantity
50
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Allocations:
Implementation:
Cost:
References:
and quality of runoff produced by storms, as well as during baseflow
conditions. TMDLs are developed on a monthly basis to isolate times
of similar weather, runoff, and instream conditions. However, at the
subwatershed level, SWMM provides daily fecal coliform count
predictions, which allows for a direct comparison with the state's WQS.
SWMM also was used to assess the effectiveness of various
implementation options (see implementation section below).
Point sources - The wasteload allocations and required reductions are
based on whichever component of the water quality standard (WQS)—
the 30-day geometric mean criteria or the 10 percent not-to exceed
criteria—is most restrictive. The TMDL analysis using SWMM
determined when (i.e., spring and summer) the highest loads occurred
and allocated the greatest reductions during those months.
Nonpoint sources - Loading from waterfowl and wildlife are not
included in the allocations because these contributions do not result
from human activities. A load allocation of zero was set for this TMDL.
Implementation of the TMDL will occur through the Municipality of
Anchorage's MS4 permit through BMPs.
The SWMM model was used to assess the effectiveness of three
implementation options. The three implementation scenarios were
simulated with the calibrated SWMM model: (1) public education-
informing the public about the benefits of "cleaning up" after their pets
was assumed to result in a 30 percent decrease in the surface build up
of fecal coliform on landscaped, street, directly connected, and
indirectly connected impervious land cover types; (2) increased street
sweeping frequency and efficiency—street sweeping frequency was
increased from monthly to weekly intervals and the efficiency was
assumed to increase to eighty percent; and (3) a combination of
scenarios 1 and 2. Simulation results suggested that a combination of
education and increased street sweeping frequency and efficiency
(scenario 3) could have a significant impact on reducing FC loading.
However, for University Lake, significant additional reductions beyond
those in scenario 3 are required to comply with both components of
the WQS (the 30-day geometric mean and 10 percent not-to-exceed
criteria).
Follow-up monitoring will be coordinated between the Department of
Environmental Conservation and the Municipality of Anchorage to track
the progress of implementation and water quality response, track BMP
effectiveness, and track the water quality to evaluate future
attainment of WQS.
Cost information is not available in the TMDL documentation.
Alaska Department of Environmental Conservation. May 2005. Total Maximum Daily Load for Fecal
Coliform in Chester Creek, University Lake, and Westchester Lagoon, Anchorage, Alaska.
http://www.dec.state.ak.us/water/tmdl/pdfs/chestercrwatershedTMDLEPAFinal.pdf
Huber W.C. and R.E. Dickinson. 2001. Stormwater Management Model User's Manual. Version 4.4.
Athens, GA.
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Tualatin River Subbasin
Stormwater Source TMDL (2001)
Oregon, USEPA Region 10
TMDL at a Glance
Subbasin:
Watershed size:
Key beneficial uses:
Impaired by:
Pollutant(s):
Sources considered:
Model(s) used:
TMDL Web link:
TMDL Highlights
Affected water uses:
Applicable WQS:
TEMPERATURE
Wilamette River Basin
712 square miles
Salmonid fish spawning, incubation, fry emergence, and rearing
(temperature); water contact recreation (bacteria); salmonid spawning,
rearing, and passage (dissolved oxygen); and salmonid fish spawning,
salmonid fish rearing, resident fish and aquatic life, anadromous fish
passage, water contact recreation, and aesthetic quality (pH/chlorophyll a)
Heat from human caused increases in solar radiation loading to the stream
network, heat from warmwater discharges to surface waters of human
origin, pathogens, insufficient concentrations of dissolved oxygen, and
human caused increases in instream phosphorus concentrations
Temperature, bacteria, total phosphorus, ammonia, and volatile solids
Point sources - Wastewater treatment plants (WWTPs) covered by
municipal separate sewer system (MS4) NPDES permits, concentrated
animal feeding operation (CAFO), septic systems
Nonpoint sources - septic systems, forest land use, and non-regulated
runoff (urban, rural, agricultural, and forest)
Event-based, unit load hydrology model, Steady state water quality
model, Streeter-Phelps equation, Water quality model, Mass balance
analysis, "simple method", Reference condition
http://www.deq.state.or.us/wq/TMDLs/docs/willamettebasin/tualatin/tmd
Iwamp.Ddf
Salmonid fish spawning, incubation, fry emergence, and rearing;
anadromous fish passage; resident fish and aquatic life; water contact
recreation; fishing; and aesthetic quality.
Numeric standards are based on temperature that protects various
salmonid life stages. Narrative standards specify conditions that
deserve special attention, such as the presence of threatened and
endangered cold water species. Dissolved oxygen (DO) violations are
also a trigger for the temperature standard. A surrogate measure
used is percent effective shade (expressed as the percent reduction in
potential solar radiation load delivered to the water surface) to help
52
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BACTERIA
DISSOLVED
OXYGEN (DO)
pH/CHL
Technical approach:
Key indicator(s)
TEMPERATURE
BACTERIA
DO
pH/CHL
Source assessment
TEMPERATURE
BACTERIA
DO
pH/CHL
translate the nonpoint source (NPS) solar radiation heat loading
allocations.
Numeric and narrative standards apply. The numeric standard states
that organisms of the coliform group commonly associated with fecal
sources shall not exceed: (1) a 30-day log mean of 126 E. coli
organisms per 100 ml, based on a minimum of five samples, and (2)
no single sample shall exceed 406 E. coli organisms per 100 ml.
Numeric and narrative standards apply. The applicable criteria are
determined by the presence of cool- or cold-water aquatic life and the
life stages of any salmonids present (spawning, rearing, etc.) and
based on fish survey information, habitat assessments, and
professional judgment.
Numeric and narrative standards apply. There are three WQS
impacted by elevated chlorophyll a concentrations—pH, DO, and
aesthetics. The applicable average chlorophyll a value used to
determine possible beneficial use impairment is 0.015 mg/L.
Heat per unit time or kcal per day, as well as percent effective shade,
which is used as a surrogate measure for NPS pollutant loading
E. coli
Sediment oxygen demand (SOD), settleable volatile solids in runoff,
and ammonia
Total phosphorus (TP)
Natural background sources were determined to contribute 44% of the
heat loading. Anthropogenic NPS heat loading is the dominant
pollutant source, contributing 49%, and the heat loading from NPDES
point sources is relatively small (7%).
An initial subbasin source assessment was conducted to determine
whether the sources were associated with runoff. The assessment was
made by grouping the individual samples by whether there was likely
to be runoff at the time of sampling. It was estimated that runoff
would occur when the rainfall on the day of sampling was greater than
0.1 inches for urbanized watersheds and 0.2 for watersheds with
mixed uses. Urban runoff is likely a significant source of bacteria
(e.g., from pet and other animal waste, illegal dumping, failing septic
systems, and sanitary sewer cross-connections and overflows).
A volatile solids source assessment identified runoff as probably the
most important source of solids affecting SOD. Ammonia is the
primary target for TMDL development to address the DO levels in the
lower mainstem of the Tualatin River because the primary sources of
ammonia and the technology to control these loadings are well
understood. However, the control of ammonia by itself will not result
in full attainment of the DO criteria; and therefore, reductions in SOD
on the mainstem are necessary.
The sources of TP are divided into four broad categories: background
sources, WWTPs, runoff, and other sources. Data on TP
concentrations for agricultural and forested land runoff in the subbasin
are lacking, but the available data indicate that the phosphorus
concentrations from these sources exceed natural background
concentrations. The source assessment for Oswego Lake was
conducted separately, and five primary phosphorus sources were
identified in a 1987 diagnostic and restoration analysis of the lake:
precipitation, groundwater, releases from sediment, input from the
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Models
TEMPERATURE
BACTERIA
DO
pH/CHL
Allocations:
Point sources
TEMPERATURE
BACTERIA
DO
Tualatin River (via Oswego Canal), and input from the local watershed
tributaries.
Natural background loading was calculated by simulating the solar
radiation heat loading that resulted with system potential near-stream
vegetation. Percent effective shade surrogates were developed to help
translate the NPS solar radiation heat loading allocations, which can be
calculated directly from the loading capacity, quantified in the field, or
through calculations. The system potential temperatures determined
by computer modeling also were used to assign WLAs to the point
sources.
An event-based, unit load hydrology model was used to evaluate
precipitation-driven bacteria loadings from specific land uses.
Allocations for non-runoff periods were based on a straightforward
analysis of instream bacteria levels and the percent reductions
necessary to achieve standards.
TRIBUTARIES: A steady state water quality model was developed for
the various representative streams to evaluate the sensitivity of DO
concentrations to the parameters that appear to impact DO the most
on the various representative stream segments. In Scoggins Creek,
an analysis of the discharges from a lumber mill (Forestex) was
conducted using the Streeter-Phelps equation.
MAINSTEM: USGS developed a water quality model based on
ammonia data to estimate DO levels for the lower mainstem of the
river (Rounds et al. 1999 and TBTAC 1997).
TRIBUTARIES: A mass balance spreadsheet analysis was used to
estimate the concentrations that would result on the mainstem of the
Tualatin River due to background conditions. The total loadings from
runoff sources was estimated using the "simple method" in which the
amount of runoff for a specific time period is multiplied by the
estimated pollutant concentration to give a total loading for that time
period.
OSWEGO LAKE: A reference stream was used to determine the
background wet weather storm concentration of phosphorus in the
tributary streams in the natural Oswego Lake watershed.
Point sources are allowed heat that produces a 0.25°F increase over
background temperatures within the zone of dilution.
The allocations for runoff sources of bacteria were based on a
computer model that estimates the bacteria loadings from specific land
uses during rain events. Four WWTPs, sources covered by municipal
separate storm sewer system (MS4) NPDES permits, and concentrated
animal feeding operation (CAFO) direct discharges require bacteria
WLAs. CAFO direct discharges and septic systems are allocated
wasteload allocations (WLAs) of 0 during runoff events and all other
times during summer and winter.
SOD: The SOD reductions (ranging from 20-50%) for the mainstem
and tributaries are addressed through volatile solids WLAs in runoff.
AMMONIA: This TMDL updates the 1988 ammonia TMDL because
subsequent computer modeling estimated that the allocations were not
stringent enough to meet DO criteria in the critical late summer and
early fall months and may have been too stringent in the spring/early
summer when the river's assimilative capacity was greater. The
ammonia monthly mean WLAs were calculated based on the WLA
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pH/CHL
Nonpoint sources
TEMPERATURE
BACTERIA
DO
pH/CHL
Implementation:
Water quality
management plan
design concentration multiplied by the monthly median flow, and the
WWTP design concentrations are based on the loading capacity.
TRIBUTARIES: The runoff allocations associated with point sources
include point sources other than WWTPs. The allocations have been
provided in concentration- and load-based units. The TMDL states that
this combination of measures is considered appropriate because it
addresses the WQS and lends itself to the design of control measures.
OSWEGO LAKE: The WLAs are set equal to the background loadings
and are allocated to discharges from the City of Lake Oswego's MS4.
The allocations (LAs and WLAs) are divided into two categories-
summer (May 1 through October 31) and winter (November 1 through
April 30).
The NPS heat load allocation (LA) is translated effective shade
surrogate measures that linearly determine the NPS solar radiation
allocation. Effective shade surrogate measures provide site-specific
targets for land managers. Anthropogenic nonpoint sources of solar
radiation received an allocation of zero.
Bacteria load allocations were derived for septic systems, forest land
use, and runoff and other discharges and were calculated using event
mean concentrations for storm events.
SOD: Similar to the point sources, the SOD reductions (ranging from
20-50%) for the mainstem and tributaries NPS are addressed through
volatile solids LAs in runoff.
AMMONIA: The LA design concentrations were set to result in
allocations similar to the previous ammonia load allocations
documented in the 1998 ammonia TMDL.
TRIBUTARIES: LAs are categorized as background (groundwater)
sources and runoff. A narrative LA was given to riparian bank erosion:
"No excessive riparian bank erosion may occur in the Tualatin River
Subbasin during the TMDL season."
LAKE OSWEGO: Like the point sources, the nonpoint source LAs are
set equal to the background loadings. The LAs are for all other
discharges and instream contributions (e.g., instream erosion).
A water quality management plan (WQMP) has been developed to
address these TMDLs, and it focuses on protecting and planting trees
along riparian areas; urban stormwater and agricultural/forestry runoff
management; temperature control of other permitted discharges; and
ammonia, phosphorus, and temperature control of discharges from
WWTPs.
The WQMP includes a table with management measures and source
categories sorted by parameter. This table is designed to be used by
the designated management agencies (DMAs) as guidance for
selecting management measures to be included in their
implementation plans. Each DMA will be responsible for examining the
categories to determine if the source and/or management measure is
applicable within their jurisdiction. The WQMP is in appendix I of the
TMDL. As the WQMP is implemented, the Department of
Environmental Quality expects that management agencies will develop
benchmarks for attainment of TMDL surrogates that can be used to
measure progress.
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Habitat and flow • The habitat and flow modification "impairments" associated with the
impairments exceedance of biological criteria will be addressed in management
plans to be developed by the DMAs.
Heat credits • The TMDL discusses the use of "heat credits" by calculating the heat
reductions associated with flow augmentation and relating those
reductions to the heat increases caused by effluent discharge.
Cost: • Cost information is not available in the TMDL documentation.
References:
Oregon Department of Environmental Quality. August 2001. Tualatin Subbasin Total Maximum
Daily Load. Available at
http://www.dea.state.or. us/wg/TMDLs/docs/willamettebasin/tualatin/tmdlwqmD.Ddf
Rounds, S.A., Wood, T.M., and Lynch, D.D. 1999. Modeling Discharge, Temperature, and Water
Quality in the Tualatin River, Oregon (Water-Supply Paper 2465-B) (p. 115).
Tualatin Basin Technical Advisory Committee (TBTAC), Water Quality Modeling Subcommittee.
1997. Technical Review of Tualatin River Water Quality Monitoring.
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