mauvaise-011011-revision

              Mauvaise Terre Creek Watershed
TMDL
Prepared for Illinois Environmental Protection Agency
January 2011 Revision
Mauvaise Terre Creek (IL_DD-04): Fecal Coliform
Mauvaise Terre Lake (IL_SDL): Total Phosphorus, Manganese,
Nitrate
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TABLE OF CONTENTS
INTRODUCTION ...............................................................................................................1
1 PROBLEM IDENTIFICATION ....................................................................................3
2 REQUIRED TMDL ELEMENTS .................................................................................5
3 WATERSHED CHARACTERIZATION ...................................................................13
4 DESCRIPTION OF APPLICABLE STANDARDS AND NUMERIC TARGETS ..15
4.1 Designated Uses and Use Support .....................................................................15
4.2 Water Quality Criteria ........................................................................................15
4.2.1 Total Phosphorus ...................................................................................... 15
4.2.2 Manganese ................................................................................................ 16
4.2.3 Nitrate ....................................................................................................... 16
4.2.4 Fecal Coliform .......................................................................................... 16
4.3 Development of TMDL Targets ........................................................................16
4.3.1 Total Phosphorus ...................................................................................... 16
4.3.2 Manganese ................................................................................................ 16
4.3.3 Nitrate ....................................................................................................... 17
4.3.4 Fecal Coliform .......................................................................................... 17
5 DEVELOPMENT OF WATER QUALITY MODELS ..............................................19
5.1 BATHTUB Model .............................................................................................19
5.1.1 Model Selection ........................................................................................ 19
5.1.2 Modeling Approach .................................................................................. 19
5.1.3 Model Inputs ............................................................................................. 20
5.1.3.1 Model Options ...................................................................................... 20
5.1.3.2 Global Variables ................................................................................... 21
5.1.3.3 Reservoir Segmentation ........................................................................ 22
5.1.3.4 Tributary Loads ..................................................................................... 24
5.1.4 BATHTUB Calibration ............................................................................. 24
5.2 Load Duration Curve Approach .........................................................................25
5.2.1 Model Selection ........................................................................................ 25
5.2.2 Approach ................................................................................................... 25
5.2.3 Data Inputs ................................................................................................ 25
5.2.3.1 Manganese and Nitrate ......................................................................... 25
5.2.3.2 Fecal coliform ....................................................................................... 26
5.2.4 Analysis..................................................................................................... 26
5.2.4.1 Manganese ............................................................................................ 26
5.2.4.2 Nitrate ................................................................................................... 27
5.2.4.3 Fecal coliform ....................................................................................... 28
6 TMDL DEVELOPMENT ............................................................................................31
6.1 Phosphorus (Mauvaise Terre Lake) ...................................................................31
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6.1.1 Calculation of Loading Capacity .............................................................. 31
6.1.2 Allocation .................................................................................................. 31
6.1.3 Critical Condition...................................................................................... 32
6.1.4 Seasonality ................................................................................................ 32
6.1.5 Margin of Safety ....................................................................................... 32
6.2 Manganese (Mauvaise Terre Lake) ...................................................................32
6.2.1 Calculation of Loading Capacity .............................................................. 32
6.2.2 Allocation .................................................................................................. 33
6.2.3 Critical Condition...................................................................................... 34
6.2.4 Seasonality ................................................................................................ 34
6.2.5 Margin of Safety ....................................................................................... 34
6.3 Nitrate (Mauvaise Terre Lake) ...........................................................................34
6.3.1 Calculation of Loading Capacity .............................................................. 34
6.3.2 Allocation .................................................................................................. 35
6.3.3 Critical Condition...................................................................................... 36
6.3.4 Seasonality ................................................................................................ 36
6.3.5 Margin of Safety ....................................................................................... 36
6.4 Fecal Coliform (Mauvaise Terre Creek) ............................................................37
6.4.1 Calculation of Loading Capacity .............................................................. 37
6.4.2 Allocation .................................................................................................. 37
6.4.3 Critical Condition...................................................................................... 39
6.4.4 Seasonality ................................................................................................ 40
6.4.5 Margin of Safety ....................................................................................... 40
7 PUBLIC PARTICIPATION AND INVOLVEMENT ................................................42
8 ADAPTIVE IMPLEMENTATION PROCESS ..........................................................44
REFERENCES ..................................................................................................................46
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LIST OF TABLES
Table 1. BATHTUB Model Options for Mauvaise Terre Lake....................................... 21
Table 2. Manganese Loading Capacity ............................................................................. 33
Table 3. Manganese TMDL Allocation1 ........................................................................... 33
Table 4. Nitrate Loading Capacity .................................................................................... 35
Table 5. Nitrate TMDL Allocation1 .................................................................................. 36
Table 6. Mauvaise Terre Creek Fecal Coliform Loading Capacity .................................. 37
Table 7. Required Reductions in Existing Loads under Different Flow Conditions ........ 37
Table 8. Permitted Dischargers and WLAs ...................................................................... 38
Table 9. Fecal Coliform TMDL for Mauvaise Terre Creek (IL_DD-04)1 ....................... 38
LIST OF FIGURES
Figure 1. Mauvaise Terre Creek Watershed .................................................................... 14
Figure 2. Mauvaise Terre Lake Segmentation Used in BATHTUB ................................. 23
Figure 3. Manganese load duration curve for Mauvaise Terre Lake with observed loads
(triangles) .................................................................................................................. 27
Figure 4. Nitrate load duration curve for Mauvaise Terre Lake with observed loads
(triangles) .................................................................................................................. 28
Figure 5. Fecal coliform load duration curve for Mauvaise Terre Creek with observed
loads (triangles) ......................................................................................................... 28
LIST OF ATTACHMENTS
Attachment 1. BATHTUB Model Files: Mauvaise Terre Lake
Attachment 2. Load Duration Curve Analysis for Manganese
Attachment 3. Load Duration Curve Analysis for Nitrate
Attachment 4. Load Duration Curve Analysis for Fecal Coliform
Attachment 5. Responsiveness Summary
Attachment 6. Jacksonville Wastewater Treatment Plant Long Term Control Plan
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INTRODUCTION
Section 303(d) of the 1972 Clean Water Act requires States to define impaired waters and
identify them on a list, which is referred to as the 303(d) list. The State of Illinois
recently issued the 2006 303(d) list, which is available on the web at:
http://www.epa.state.il.us/water/tmdl/303d-list.html. Section 303(d) of the Clean Water
Act and EPA's Water Quality Planning and Management Regulations (40 CFR Part 130)
require states to develop Total Maximum Daily Loads (TMDLs) for water bodies that are
not meeting designated uses under technology-based controls. The TMDL process
establishes the allowable loading of pollutants or other quantifiable parameters for a
water body based on the relationship between pollution sources and instream conditions.
This allowable loading represents the maximum quantity of the pollutant that the
waterbody can receive without exceeding water quality standards. The TMDL also takes
into account a margin of safety, which reflects scientific uncertainty, as well as the effects
of seasonal variation. By following the TMDL process, States can establish water
quality-based controls to reduce pollution from both point and nonpoint sources, and
restore and maintain the quality of their water resources (USEPA, 1991).
Mauvaise Terre Creek (IL_DD-04) and Mauvaise Terre Lake (IL_SDL) are listed on the
2006 Illinois Section 303(d) List of Impaired Waters (IEPA, 2006) as waterbodies that
are not meeting their designated uses. As such, they have been targeted as high priority
waterbodies for TMDL development. This document presents the TMDLs designed to
allow these waterbodies to fully support their designated uses. The report covers each
step of the TMDL process and is organized as follows:
􀂃􈍐 Problem Identification
􀂃􈍒 Required TMDL Elements
􀂃􈍗 Watershed Characterization
􀂃􈍄 Description of Applicable Standards and Numeric Targets
􀂃􈍄 Development of Water Quality Model
􀂃􈍔 TMDL Development
􀂃􈍐 Public Participation and Involvement
􀂃􈍁 Adaptive Implementation Process
Illinois EPA revised the original TMDL document to include a more accurate
representation of the NPDES dischargers in the watershed. A notice was sent out for a
public meeting that was held in the watershed on August 31, 2010 and the comment
period ended September 30, 2010. No comments were received.
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1 PROBLEM IDENTIFICATION
The impairments in waters of the Mauvaise Terre Creek Watershed addressed in this
report are summarized below, with the parameters (causes) that they are listed for, and
the impairment status of each designated use, as identified in the 303(d) list (IEPA,
2006). TMDLs for Mauvaise Terre Creek and Mauvaise Terre Lake are included in this
report. TMDLs for North Fork Mauvaise Terre Creek (IL_DDC) for dissolved oxygen
and manganese will be conducted after additional data needed for the analysis have been
collected. While TMDLs are currently only being developed for pollutants that have
numerical water quality standards (indicated below with bold font), many controls that
are implemented to address TMDLs for these pollutants will reduce other pollutants as
well. For example, any controls to reduce phosphorus loads from watershed sources
(stream bank erosion, runoff, etc.) would serve to reduce not only phosphorus, but also
sediment loads to Mauvaise Terre Lake, as phosphorus Best Management Practices
(BMPs) are often the same or similar to sediment BMPs. Furthermore, any reduction of
phosphorus loads, either through implementation of watershed controls or dredging of
lake sediments, is expected to work towards reducing algae concentrations, as
phosphorus is the nutrient most responsible for limiting algal growth.
Mauvaise Terre Creek
Assessment Unit ID IL_DD-04
Size (length) 36.71
Listed For Fecal Coliform
Use Support1 Aquatic life (F), Fish consumption (F), Primary contact (N), Secondary
contact (X), Aesthetic quality (X)
1 F = fully supporting, N=not supporting, X = not assessed
Mauvaise Terre Lake
Assessment Unit ID IL_SDL
Size (Acres) 172
Listed For Manganese, Phosphorus, Nitrate, total suspended solids, aquatic algae
Use Support1
Aquatic life (N), Fish consumption (F), Public and food processing water
supplies (N), Primary contact (X), Secondary contact (X), Aesthetic quality
(N),
1 F = fully supporting, N=not supporting, X = not assessed
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2 REQUIRED TMDL ELEMENTS
USEPA Region 5 guidance for TMDL development requires TMDLs to contain eleven
specific components. Each of those components is summarized below, by waterbody.
Mauvaise Terre Creek (IL_DD-04)
1. Identification of Waterbody, Pollutant of Concern, Pollutant Sources,
and Priority Ranking: Mauvaise Terre Creek, HUC 0713001104. The
pollutant of concern addressed in this TMDL is fecal coliform. Potential
sources contributing to the listing of Mauvaise Terre Creek include: runoff
from pastureland and animal feeding operations, private sewage disposal
systems, municipal point sources, and combined sewer overflows.
Mauvaise Terre Creek is reported on the 2006 303(d) list as being in
category 5, meaning available data and/or information indicate that at least
one designated use is not being supported or is threatened, and a TMDL is
needed (IEPA, 2006).
2. Description of Applicable Water Quality Standards and Numeric
Water Quality Target: The IEPA guidelines (IEPA, 2006) for identifying
fecal coliform as a cause of impairment in streams state that fecal coliform
is a potential cause of impairment of the primary contact use if the
geometric mean of all samples collected during May through October
(minimum five samples) is greater than 200 cfu/100 ml, or if greater than
10% of all samples exceed 400 cfu/100 ml (cfu = colony forming units).
For the Mauvaise Terre Creek TMDL for fecal coliform, the target is set at
meeting 200 cfu/100 ml across the entire flow regime during May-
October.
3. Loading Capacity – Linking Water Quality and Pollutant Sources:
A load capacity calculation was completed to determine the maximum
fecal coliform loads that will maintain compliance with the fecal coliform
standard for May through October under a range of flow conditions:
Flow
Percentile
Range
Median
Observed
Mauvaise Terre
Creek Flow (cfs)
Load Capacity
(cfu/day)
60-100 1.56 7.63E+09
30-60 35.1 1.72E+11
0-30 139 6.81E+11
4. Load Allocations (LA): Load allocations designed to achieve compliance
with the above TMDL are calculated for the May-October period by the
following equation:
Load allocation = load capacity – MOS – ΣWLAs
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Flow
Percentile
Range
Median
Observed
Mauvaise
Terre Creek
Flow (cfs)
Load
Allocation
(LA)
(cfu/day)
60-100 1.56 0
30-60 35.1 1.14E+11
0-30 139 2.28E+11
5. Wasteload Allocations (WLA): The WLA for the three point source
dischargers of fecal coliform in the Mauvaise Terre Creek watershed was
calculated from the current permitted flows and a fecal coliform
concentration consistent with the TMDL target (200 cfu/100 ml). The WLA
for these facilities equals 5.84E+10 cfu/day for designed average flow
conditions and 1.17E+11 for maximum design flow conditions, during
periods of no CSO discharge and applies at the point where the segment
impairment begins. The Jacksonville STP also has a permit for three
combined sewer overflows (CSOs) that may discharge during wet weather:
outfalls 002, 003 and 004. The CSO WLA is based on the maximum
primary treatment capacity of 57.93 MGD that can discharge through outfall
004 and the average combined discharge of 1.5 MGD from outfalls 002 and
003. The total WLA for the CSOs equals 4.5E+11 cfu/day and must not
exceed an average of four overflow events per year.
6. Margin of Safety: The TMDL contains an implicit margin of safety for
fecal coliform, through the use of multiple conservative assumptions. The
TMDL target (no more than 200 cfu/100 ml at any time) is more
conservative than the more restrictive portion of the fecal coliform water
quality standard (geometric mean of 200 cfu/100 ml for all samples
collected May through October). An additional implicit Margin of Safety
is provided via the use of a conservative model to define load capacity.
The model assumes no decay of bacteria that enter the river, and therefore
represents an upper bound of expected concentrations for a given pollutant
load.
7. Seasonal Variation: The TMDL was conducted with an explicit
consideration of seasonal variation. The approach used for the TMDL
evaluated seasonal loads because only May through October water quality
data were used in the analysis, consistent with the specification that the
standard only applies during this period. The fecal coliform standard will
be met regardless of flow conditions in the applicable season because the
load capacity calculations specify target loads for the entire range of flow
conditions that are possible to occur at any given point in the season where
the standard applies.
8. Reasonable Assurances: In terms of reasonable assurances for point
sources, Illinois EPA has the NPDES permitting program for treatment
plants, stormwater permitting and CAFO permitting. The permits for the
point source dischargers in the watershed will be modified if necessary as
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part of the permit review process (typically every 5 years), to ensure that
they are consistent with the applicable wasteload allocation.
In terms of reasonable assurances for nonpoint sources, Illinois EPA is committed
to:
􀂃􈍃 Convene local experts familiar with nonpoint sources of pollution in the
watershed
􀂃􈍅 Ensure that they define priority sources and identify restoration
alternatives
􀂃􈍄 Develop a voluntary implementation plan that includes accountability.
Local agencies and institutions with an interest in watershed management
will be important for successful implementation of this TMDL. Detail on
watershed activities is provided in the Stage 1 Report.
9. Monitoring Plan to Track TMDL Effectiveness: A monitoring plan will
be prepared as part of the implementation plan.
10. Transmittal Letter: A transmittal letter has been prepared and is included
with the TMDL.
11. Public Participation: Numerous opportunities were provided for local
watershed institutions and the general public to be involved. The Agency
and its consultant met with local municipalities and agencies in summer
2004 to gather and share information and initiate the TMDL process. A
number of phone calls were made to identify and acquire data and
information (listed in the Stage 1 Report). As quarterly progress reports
were produced, the Agency posted them to their website. In March 2005, a
public meeting was conducted in Jacksonville, Illinois to present the
results of the Stage 1 characterization work. In July 2006, a second public
meeting was conducted in Jacksonville, Illinois to present the TMDL. A
future meeting will be held for this revision process.
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Mauvaise Terre Lake (IL_SDL)
1. Identification of Waterbody, Pollutant of Concern, Pollutant Sources,
and Priority Ranking: Mauvaise Terre Lake, HUC 0713001104. The
pollutants of concern addressed in this report are total phosphorus,
manganese, and nitrate. Potential sources contributing to the listing of
Mauvaise Terre Lake include: lake bottom sediments, recreational
activities (i.e., golf courses) and agricultural sources for total phosphorus,
natural background sources for manganese, and agricultural runoff and
recreational activities (i.e., golf courses) for nitrate. Mauvaise Terre Lake
is reported on the 2006 303(d) list as being in category 5, meaning
available data and/or information indicate that at least one designated use
is not being supported or is threatened, and a TMDL is needed (IEPA,
2006).
2. Description of Applicable Water Quality Standards and Numeric
Water Quality Target: The water quality standard for total phosphorus
to protect aquatic life and aesthetic quality uses in Illinois lakes is 0.05
mg-P/l. For the Mauvaise Terre Lake phosphorus TMDL, the target is set
at the water quality criterion for total phosphorus of 0.05 mg-P/l.
The water quality standard for manganese in Illinois waters designated as
public and food processing water supplies is 150 ug/l. For the Mauvaise
Terre Lake TMDL, the target is set at the water quality criterion for
manganese of 150 ug/l.
The water quality standard for nitrate in Illinois waters that serve as
public and food processing water supplies is 10 mg-N/l. For the Mauvaise
Terre Lake nitrate TMDL, the target is set at the water quality criterion for
nitrate of 10 mg-N/l.
3. Loading Capacity – Linking Water Quality and Pollutant Sources:
The water quality model BATHTUB was applied to determine that the
maximum phosphorus load that will maintain compliance with the
phosphorus standard is 60.8 kg-P/month (2.03 kg-P/day).
A load capacity calculation was completed to determine the maximum
manganese and nitrate loads that will maintain compliance with their
respective water quality standards for a range of flow conditions. This
calculation is based on flow multiplied by the water quality standard of
150 ug/l for manganese, and 10 mg/l for nitrate.
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Mauvaise Terre
River Flow
(cfs)
Allowable
Manganese
Load (kg/day)
Allowable
Nitrate Load
(kg-N/day)
0.5 0.18 12.2
1 0.37 24.5
2 0.73 48.9
5 1.84 122.3
10 3.67 244.7
20 7.34 489.4
30 11.01 734.1
40 14.68 978.7
50 18.35 1223.4
4. Load Allocations (LA): The Load Allocation designed to achieve
compliance with the above TMDL is as follows:
Total phosphorus: 54.72 kg-P/month (1.827 kg-P/day)
Manganese and nitrate (see table below)
Mauvaise
Terre River
Flow (cfs)
Manganese LA
(kg/day)
Nitrate LA
(kg-N/day)
0.5 0.17 11.0
1 0.33 22.0
2 0.66 44.0
5 1.65 110.1
10 3.30 220.2
20 6.61 440.4
30 9.91 660.6
40 13.21 880.9
50 16.52 1101.1
5. Wasteload Allocations (WLA): There are no point source dischargers in
the Mauvaise Terre Lake watershed; therefore the wasteload allocation is
not calculated.
6. Margin of Safety: The TMDL contains an explicit margin of safety
(MOS) of 10% for total phosphorus. The phosphorus value was set to
reflect the uncertainty in the BATHTUB model predictions. The resulting
MOS for total phosphorus is 6.08 kg-P/month (0.203 kg-P/day).
The manganese and nitrate TMDLs contain an implicit Margin of Safety and an
explicit MOS. The implicit MOS is provided via the use of a conservative model
to define load capacity. The model assumes no loss of manganese or nitrate that
enters the lake, and therefore represents an upper bound of expected
concentrations for a given pollutant load. The TMDLs also contain an explicit
margin of safety of 10%. This 10% margin of safety was included in addition to
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the implicit margin of safety to address potential uncertainty in the effectiveness
of load reduction alternatives. This margin of safety can be reviewed in the future
as new data are developed.
The following table provides the MOS for manganese and nitrate:
Mauvaise Terre
River Flow (cfs)
Manganese
MOS (kg/day)
Nitrate MOS
(kg-N/day)
0.5 0.02 1.2
1 0.04 2.4
2 0.07 4.9
5 0.18 12.2
10 0.37 24.5
20 0.73 48.9
30 1.10 73.4
40 1.47 97.9
50 1.84 122.3
7. Seasonal Variation: The TMDL was conducted with an explicit
consideration of seasonal variation. The BATHTUB model used for the
phosphorus TMDL is designed to accommodate the evaluation of monthly
loads. The monthly loading analysis is appropriate due to the short nutrient
residence time. The monthly duration for the loading was determined
based on a calculation of a phosphorus residence time in Mauvaise Terre
Lake on the order of weeks.
The load capacity calculations for manganese and nitrate take into account
seasonal variations by specifying target loads for the entire range of flow
conditions that are possible to occur in any given year.
8. Reasonable Assurances: There are no point source dischargers in the
watershed, so reasonable assurances are not discussed for point source
dischargers.
In terms of reasonable assurances for nonpoint sources, Illinois EPA is committed
to:
􀂃􈍃 Convene local experts familiar with nonpoint sources of pollution in the
watershed
􀂃􈍅 Ensure that they define priority sources and identify restoration
alternatives
􀂃􈍄 Develop a voluntary implementation plan that includes accountability.
Local agencies and institutions with an interest in watershed management
will be important for successful implementation of this TMDL. Detail on
watershed activities is provided in the Stage 1 Report.
9. Monitoring Plan to Track TMDL Effectiveness: A monitoring plan will
be prepared as part of the implementation plan.
10. Transmittal Letter: A transmittal letter has been prepared and is included
with this TMDL.
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11. Public Participation: Numerous opportunities were provided for local
watershed institutions and the general public to be involved. The Agency
and its consultant met with local municipalities and agencies in summer
2004 to gather and share information and initiate the TMDL process. A
number of phone calls were made to identify and acquire data and
information (listed in the Stage 1 Report). As quarterly progress reports
were produced, the Agency posted them to their website. A public meeting
was conducted in Jacksonville, Illinois in March 2005 to present the
results of the Stage 1 characterization work. A second public meeting was
conducted in Jacksonville, Illinois in July 2006 to present the TMDL.
Another meeting will be held at a later date to present the implementation
plan.
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3 WATERSHED CHARACTERIZATION
The Stage 1 Report presents and discusses information describing the Mauvaise Terre
Creek watershed to support the identification of sources contributing to the listed
impairments as applicable. The Stage 1 Report is divided into four sections, called
Quarterly Progress Reports. The watershed characterization is discussed in the First
Quarterly Progress Report. Watershed characterization activities were focused on
gaining an understanding of key features of the watershed, including geology and soils,
climate, land cover, hydrology, urbanization and population growth, point source
discharges and watershed activities.
The impaired waterbodies addressed in this report are in the Mauvaise Terre Creek
watershed, located in Morgan and Scott counties in west-central Illinois. The two
waterbodies of concern are Mauvaise Terre Lake (IL_SDL) and Mauvaise Terre Creek
downstream of Town Brook (IL_DD-04). Mauvaise Terre Lake lies in Morgan County,
while Mauvaise Terre Creek flows through both Morgan and Scott Counties. Mauvaise
Terre Lake was constructed by damming the upper part of Mauvaise Terre Creek (above
the North Fork). The lake has a surface area of 172 acres and serves as a source of
drinking water for Jacksonville and several surrounding communities. Most of the water
supply, however, comes from wells located 26 miles from the Jacksonville (City of
Jacksonville, 2004). Mauvaise Terre Lake is approximately “L” shaped, with an arm
extending west from the inlet, and a second arm extending north to the dam. Mauvaise
Terre Lake is connected near the corner of the “L” to a smaller lake called Morgan Lake.
Figure 1 shows a map of the watershed, and includes some key features such as
waterways, impaired waterbodies, public water intakes and other key features. The map
also shows the locations of point source discharges that have a permit to discharge under
the National Pollutant Discharge Elimination System (NPDES).
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Figure 1. Mauvaise Terre Creek Watershed
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4 DESCRIPTION OF APPLICABLE STANDARDS AND
NUMERIC TARGETS
A water quality standard includes the designated uses of the waterbody, water quality
criteria to protect designated uses, and an antidegradation policy to maintain and protect
existing uses and high quality waters. Water quality criteria are sometimes in a form that
are not directly amenable for use in TMDL development and may need to be translated
into a target value for TMDLs. This section discusses the applicable designated uses, use
support, criteria and TMDL targets for waterbodies in the Mauvaise Terre Creek
watershed that are addressed in this report.
4.1 DESIGNATED USES AND USE SUPPORT
Water quality assessments in Illinois are based on a combination of chemical (water,
sediment and fish tissue), physical (habitat and flow discharge), and biological
(macroinvertebrate and fish) data. Illinois EPA conducts its assessment of water bodies
using a set of seven designated uses: aquatic life, aesthetic quality, indigenous aquatic life
(for specific Chicago-area waterbodies), primary contact (swimming), secondary contact,
public and food processing water supply, and fish consumption (IEPA, 2006). For each
water body, and for each designated use applicable to the water body, Illinois EPA’s
assessment concludes one of two possible “use-support” levels:
• Fully Supporting (the water body attains the designated use); or
• Not Supporting (the water body does not attain the designated use).
Water bodies assessed as “Not Supporting” for any designated use are identified as
impaired. Waters identified as impaired based on biological (macroinvertebrate,
macrophyte, algal and fish), chemical (water, sediment and fish tissue), and/or physical
(habitat and flow discharge) monitoring data are placed on the 303(d) list. Potential
causes and sources of impairment are also identified for impaired waters (IEPA, 2006).
Following the U.S. EPA regulations at 40 CFR Part 130.7(b)(4), the Illinois Section
303(d) list was prioritized on a watershed basis. Illinois EPA watershed boundaries are
based on the USGS ten-digit hydrologic units to provide the state with the ability to
address watershed issues at a manageable level and document improvements to a
watershed’s health (IEPA, 2006).
4.2 WATER QUALITY CRITERIA
Illinois has established water quality criteria and guidelines for allowable concentrations
of total phosphorus, manganese, nitrate and fecal coliform under its CWA Section 305(b)
program, as summarized below. A comparison of available water quality data to these
criteria is provided in the Stage 1 Report.
4.2.1 Total Phosphorus
The IEPA guidelines (IEPA, 2006) for identifying total phosphorus as a cause of
impairment in lakes greater than 20 acres in size, state that phosphorus is a potential
cause of impairment of the aesthetic quality use if there is at least one exceedance of the
applicable standard (0.05 mg/L) during the most recent year of data from the Ambient
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Lake Monitoring Program or the Illinois Clean Lakes Program. The available data
support the listing of phosphorus as a cause of impairment in Mauvaise Terre Lake, as
discussed in the Stage 1 Report.
4.2.2 Manganese
The water quality standard for manganese in Illinois waters designated as public and food
processing water supplies is 150 ug/l. The public and food processing water supply
guidelines for inland lakes indicate impairment if more than 10% of the observations
measured since 1999 exceed 150 ug/L. The available data confirm that the listing of
Mauvaise Terre Lake for manganese is appropriate based on IEPA’s guidelines, as
discussed in the Stage 1 Report.
4.2.3 Nitrate
The IEPA guidelines (IEPA, 2006) for identifying nitrate as a cause of impairment in
waterbodies used for public and food processing water supply, state that nitrate is a
potential cause of impairment of the public and food processing water supply use if more
than 10% of the observations exceed the applicable nitrate standard (10 mg-N/l) for raw
water. The available data support the listing of nitrate as a cause of impairment in
Mauvaise Terre Lake, as discussed in the Stage 1 Report.
4.2.4 Fecal Coliform
The IEPA guidelines (IEPA, 2006) for identifying fecal coliform as a cause of
impairment in streams state that fecal coliform is a potential cause of impairment of the
primary contact use if the geometric mean of all samples collected during May through
October (minimum five samples) is greater than 200/100 ml, or if greater than 10% of all
samples exceed 400/100 ml. The available data support the listing of fecal coliform as a
cause of impairment in Mauvaise Terre Creek (IL_DD-04), as discussed in the Stage 1
Report.
4.3 DEVELOPMENT OF TMDL TARGETS
The TMDL target is a numeric endpoint specified to represent the level of acceptable
water quality that is to be achieved by implementing the TMDL. Where possible, the
water quality criterion for the pollutant of concern is used as the numeric endpoint. When
appropriate numeric standards do not exist, surrogate parameters must be selected to
represent the designated use.
4.3.1 Total Phosphorus
For the Mauvaise Terre Lake phosphorus TMDL, the target is set at the water quality
criterion for total phosphorus of 0.05 mg-P/l.
4.3.2 Manganese
For the Mauvaise Terre Lake manganese TMDL, the target is set at the water quality
criterion for manganese of 150 ug/l.
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4.3.3 Nitrate
For the Mauvaise Terre Lake nitrate TMDL, the target is set at the water quality criterion
for nitrate of 10 mg-N/l.
4.3.4 Fecal Coliform
For Mauvaise Terre Creek (IL_DD-04) fecal coliform TMDL, the target was set at 200
cfu/100 ml.
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5 DEVELOPMENT OF WATER QUALITY MODELS
Water quality models are used to define the relationship between pollutant loading and
resulting water quality. The TMDL for phosphorus is based upon the BATHTUB model.
The TMDLs for fecal coliform, manganese and nitrate utilize a Load Duration Curve
method in addition to a Load Capacity Calculation. The development of the BATHTUB
model and the Load Duration Curve Approach are described in this section. The load
capacity calculation is described in Section 6. Section 5 includes information on:
􀂃􈍍 Model selection
􀂃􈍍 Modeling approach
􀂃􈍍 Model inputs
􀂃􈍍 Model calibration (only for BATHTUB)/Analysis (for load duration)
5.1 BATHTUB MODEL
The BATHTUB water quality model was used to define the relationship between external
phosphorus loads and the resulting concentrations of total phosphorus in Mauvaise Terre
Lake.
5.1.1 Model Selection
A detailed discussion of the model selection process for the Mauvaise Terre Creek
watershed is provided in the Stage 1 Report.
Of the models discussed , the BATHTUB model (Walker, 1985) was selected to address
phosphorus impairments to Mauvaise Terre Lake. The BATHTUB model was selected
because it does not have extensive data requirements (and can therefore be applied with
existing data), yet still provides the capability for calibration to observed lake data.
BATHTUB has been used previously for several reservoir TMDLs in Illinois, and has
been cited as an effective tool for lake and reservoir water quality assessment and
management, particularly where data are limited (Ernst et al., 1994).
BATHTUB was used to predict the relationship between phosphorus load and resulting
in-lake phosphorus concentrations.
5.1.2 Modeling Approach
The approach selected for the phosphorus TMDL is based upon discussions with IEPA
and the Scientific Advisory Committee. The approach consists of using existing empirical
data to define current loads to the lake, and using the BATHTUB model to define the
extent to which these loads must be reduced to meet water quality standards. This
approach corresponds to Alternative 1 in the detailed discussion of the model selection
process provided in the Stage 1 Report. Implementation plans for agricultural sources
will require voluntary controls, applied on an incremental basis. The approach taken for
these TMDLs, which requires no additional data collection and can be conducted
immediately, will expedite these implementation efforts.
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Determination of existing loading sources and prioritization of restoration alternatives
may be conducted by local experts as part of the implementation process (see Section 8).
Based upon their recommendations, a voluntary implementation plan can be developed
that includes both accountability and the potential for adaptive management.
5.1.3 Model Inputs
This section provides an overview of the model inputs required for BATHTUB
application, and how they were derived. The following categories of inputs are required
for BATHTUB:
􀂃􈍍 Model Options
􀂃􈍇 Global Variables
􀂃􈍒 Reservoir Segmentation
􀂃􈍔 Tributary Loads
5.1.3.1 Model Options
BATHTUB provides a multitude of model options to estimate nutrient concentrations in a
reservoir. Model options were entered as shown in Table 1, with the rationale for these
options discussed below. No conservative substance was being simulated, so this option
was not needed. The second order available phosphorus option was selected for
phosphorus, as it is the default option for BATHTUB. Nitrogen was not simulated,
because phosphorus is the nutrient of concern. Similarly, transparency and chlorophyll a
are not simulated.
The Fischer numeric dispersion model was selected, which is the default approach in
BATHTUB for defining mixing between lake segments. Phosphorus calibrations were
based on lake concentrations. No nitrogen calibration was required. The use of
availability factors was not required, and estimated concentrations were used to generate
mass balance tables.
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Table 1. BATHTUB Model Options for Mauvaise Terre Lake
MODEL MODEL OPTION
Conservative substance Not computed
Total phosphorus 2nd order, available phosphorus
Total nitrogen Not computed
Chlorophyll-a Not computed
Transparency Not computed
Longitudinal dispersion Fischer-numeric
Phosphorus calibration Concentrations
Nitrogen calibration None
Error analysis Not computed
Availability factors Ignored
Mass-balance tables Use estimated concentrations
5.1.3.2 Global Variables
The global variables required by BATHTUB consist of:
• The averaging period for the analysis
• Precipitation, evaporation, and change in lake levels
• Atmospheric phosphorus loads
BATHTUB is a steady state model, whose predictions represent concentrations averaged
over a period of time. A key decision in the application of BATHTUB is the selection of
the length of time over which inputs and outputs should be modeled. The length of the
appropriate averaging period for BATHTUB application depends upon the nutrient
residence time, which is the average length of time that phosphorus spends in the water
column before settling or flushing out of the lake. Guidance for the BATHTUB model
recommends that the averaging period used for the analysis be at least twice as large as
nutrient residence time for the lake of interest. For lakes such as Mauvaise Terre Lake,
which have a nutrient residence time on the order of weeks, a monthly averaging period
is recommended. The averaging period used for this analysis was set to the monthly
period.
Precipitation inputs were taken from the observed long-term annual average precipitation
data and scaled for the monthly simulation period. This resulted in a total monthly
precipitation value of 3.3 inches. Evaporation was set equal to precipitation and there was
no assumed increase in storage during the modeling period, to represent steady state
conditions. The values selected for precipitation and change in lake levels have little
influence on model predictions. Atmospheric phosphorus loads were specified using
default values provided by BATHTUB.
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5.1.3.3 Reservoir Segmentation
BATHTUB provides the capability to divide the reservoir under study into a number of
individual segments, allowing prediction of the change in phosphorus concentrations over
the length of the reservoir. The segmentation scheme selected for Mauvaise Terre Lake
was designed to provide one segment for each of the primary lake sampling stations. The
lake was divided into the segments as shown in Figure 2. The areas of segments and
watersheds for each segment were determined by Geographic Information System (GIS).
BATHTUB requires that a range of inputs be specified for each segment. These include
segment surface area, length, total water depth, and depth of thermocline and mixed
layer. Segment-specific values for segment depths were calculated from lake monitoring
data, while segment lengths and surface areas were calculated using GIS. A complete
listing of all segment-specific inputs is provided in Attachment 1.
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Figure 2. Mauvaise Terre Lake Segmentation Used in BATHTUB
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5.1.3.4 Tributary Loads
BATHTUB requires information describing tributary flow and nutrient concentrations
into each reservoir segment. The approach used to estimate flows is described below.
Total phosphorus concentrations for each major lake tributary were based upon
springtime measurements taken near the headwaters of the lake. Concentrations for small
tributaries were set equal to the assumed concentration for the major tributary. A
complete listing of all segment-specific flows and tributary concentrations is provided in
Attachment 1.
Flows to each segment were estimated using observed flows at USGS gaging stations
adjusted through the use of drainage area ratios as follows:
Flow into segment = Flow at USGS gage x Segment-specific drainage area ratio
Drainage area ratio = Drainage area of watershed contributing to model segment
Drainage area of watershed contributing to USGS gage
The USGS gage on Spring Creek at Springfield, IL (#05577500) was used in this
analysis.
Segment-specific drainage area ratios were calculated using the watershed boundaries
provided in GIS.
5.1.4 BATHTUB Calibration
BATHTUB model calibration consists of:
1. Applying the model with all inputs specified as above
2. Comparing model results to observed phosphorus data
3. Adjusting model coefficients to provide the best comparison between model
predictions and observed phosphorus data.
The BATHTUB model was initially applied with the model inputs as specified above.
Observed data for the year 1992 were used for calibration purposes, as this year provided
the most robust data set. The August in-lake data from this year were used for calibration,
as these data best reflect the steady state conditions assumed for the BATHTUB model.
Model results in segments 1, 2, and 3 initially under-predicted the observed phosphorus
data. Phosphorus loss rates in BATHTUB reflect a typical “net settling rate” (i.e. settling
minus sediment release) observed over a range of reservoirs. Under-prediction of
observed phosphorus concentrations can occur in cases of elevated phosphorus release
from lake sediments. The mismatch between model and data were corrected during the
calibration process via the addition of an internal phosphorus load of 170 mg/m2/day in
segment 3 to reflect resuspension of phosphorus from the lake bottom sediments in this
segment. The resulting predicted lake average total phosphorus concentration was 275.4
ug/l, compared to an observed average of 277.1 ug/l. This comparison represents an
acceptable model calibration. A complete listing of all the observed data used for
calibration purposes, as well as a comparison between model predictions and observed
data, is provided in Attachment 1.
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5.2 LOAD DURATION CURVE APPROACH
A load duration curve approach was used in the manganese and nitrate analysis for
Mauvaise Terre Lake. A load duration curve approach was also used in the fecal
coliform analysis for Mauvaise Terre Creek. A load duration curve is a graphical
representation of observed pollutant load compared to maximum allowable load over a
range of flow conditions. The load duration curve provides information to:
• Help identify the issues surrounding the problem and differentiate between point
and nonpoint source problems, as discussed immediately below;
• Address frequency of deviations (how many samples lie above the curve vs. those
that plot below); and
• Aid in establishing the level of implementation needed, by showing the magnitude
by which existing loads exceed standards for different flow conditions.
5.2.1 Model Selection
The load duration curve approach was selected for fecal coliform, manganese and nitrate
because it is consistent with the selected level of TMDL implementation for this TMDL
and it can be applied with the existing data. The load duration curve approach identifies
broad categories of sources over the entire range of flows, and the extent of control
required from these source categories to attain water quality standards.
5.2.2 Approach
The load duration curve approach uses stream flows for the period of record to gain
insight into the flow conditions under which exceedances of the water quality standard
occur. A load-duration curve is developed by: 1) ranking the daily flow data from lowest
to highest, calculating the percent of days these flows were exceeded, and graphing the
results; 2) translating the flow duration curve (produced in step 1) into a load duration
curve by multiplying the flows by the TMDL target; and 3) plotting observed pollutant
loads (measured concentrations times stream flow) on the same graph. Observed loads
that fall above the load duration curve exceed the maximum allowable load, while those
that fall on or below the line, do not exceed the maximum allowable load. An analysis of
the observed loads relative to the load duration curve provides information on whether
the pollutant source is point or nonpoint in nature. A more complete description of the
load duration curve approach is provided in the Stage 1 Report.
5.2.3 Data Inputs
The load duration curve approach requires a long-term flow record and concentration
measurements that are paired to flows. Data used for the load duration curve approach
are discussed below.
5.2.3.1 Manganese and Nitrate
Manganese data are available for a single location (SDL-1) in the lake, which was
monitored in 2002. All available manganese data were used in the analysis. These data
were collected by IEPA between April and October 2002 as part of IEPA’s ambient water
quality monitoring program.
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Nitrate data are available for three locations in Mauvaise Terre Lake between 1992 and
202. All available nitrate data collected by the IEPA at the most upstream lake station
(SDL-3) between 1992 and 2002 were used in the analysis. The data were collected as
part of IEPA’s ambient water quality monitoring program.
The load duration curve approach requires a matching of flows to water quality data for
the recent period. Daily flows were not available for Mauvaise Terre Lake for recent
years. Instead, daily average flows measured at the USGS gage on nearby Spring Creek
at Springfield, Illinois (05577500) were used in the analysis. Flows are available for the
period 1948-2004. The flows measured on Spring Creek were adjusted for the size of the
drainage area (i.e., they were multiplied by 0.3 because the watershed for the lake is 70%
smaller than the watershed for the Spring Creek gage).
5.2.3.2 Fecal coliform
Fecal coliform data collected by IEPA between 1990 and 2004 were used in the analysis.
The data were collected as part of IEPA’s ambient water quality monitoring program.
Only data for the months of May-October were used because the water quality standard
applies during this period.
The load duration curve approach requires a matching of flows to water quality data for
the recent period. Daily flows were not available for Mauvaise Terre Creek for recent
years. Instead, daily average flows measured at the USGS gage on nearby Spring Creek
at Springfield, Illinois (05577500) were used in the analysis. Flows are available for the
period 1948-2004. The flows measured on Spring Creek were adjusted for the size of the
drainage area (i.e., they were multiplied by 1.3 because the watershed for IL_DD-04 is
30% larger than the watershed for the Spring Creek gage).
5.2.4 Analysis
Load duration curves were developed for manganese, nitrate and fecal coliform, to
characterize pollutant problems over the entire flow regime and gain an understanding of
manganese and nitrate impairments in Mauvaise Terre Lake and fecal coliform
impairments in Mauvaise Terre Creek.
5.2.4.1 Manganese
A flow duration curve was generated by ranking daily flow data from lowest to highest,
calculating the percent of days these flows were exceeded, and graphing the results. A
load duration curve for manganese was generated by multiplying the flows in the
duration curve by the water quality standard of 150 ug/l for manganese. This is shown
with a solid line in Figure 3. Observed pollutant loads (measured concentrations
multiplied by corresponding stream flow), were plotted at triangles on the same graph.
The worksheet for this analysis is provided in Attachment 2.
The load duration curve for manganese shows that elevated concentrations are observed
only at low flows. This indicates that groundwater/natural sources are likely contributors
to manganese exceedances.
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Figure 3. Manganese load duration curve for Mauvaise Terre Lake with observed
loads (triangles)
5.2.4.2 Nitrate
A flow duration curve was generated by ranking daily flow data from lowest to highest,
calculating the percent of days these flows were exceeded, and graphing the results. A
load duration curve for nitrate was generated by multiplying the flows in the duration
curve by the water quality standard of 10 mg-N/l for nitrate. This is shown with a solid
line in Figure 4. Observed pollutant loads (measured concentrations multiplied by
corresponding stream flow), were plotted on the same graph. The worksheet for this
analysis is provided in Attachment 3.
The load duration curve shows that nitrate loads at higher flows fall above the curve,
indicating that nonpoint sources are significant contributors to nitrate exceedances.
During lower flows, nitrate loads fall below the curve, indicating compliance with the
standard during drier conditions. This information can be used to look at potential
implementation opportunities. Because it will not be feasible to eliminate all nonpoint
source loadings of nitrate in the watershed, the implementation plan (addressed in a
separate report) will need to define practical activities that will reduce loadings as much
as is feasible and practical.
1.0E-03
1.0E-02
1.0E-01
1.0E+00
1.0E+01
1.0E+02
1.0E+03
0 20 40 60 80 100
% Time Flow Exceeded
Manganese Load (kg/d)
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Figure 4. Nitrate load duration curve for Mauvaise Terre Lake with observed loads
(triangles)
5.2.4.3 Fecal coliform
A flow duration curve was generated by ranking daily flow data from lowest to highest,
calculating the percent of days these flows were exceeded, and graphing the results. A
load duration curve for fecal coliform was generated by multiplying the flows in the
duration curve by the TMDL target of 200 cfu/100 ml for fecal coliform bacteria. This is
shown with a solid line in Figure 5. Observed pollutant loads (measured concentrations
multiplied by corresponding stream flow), were plotted on the same graph. The
worksheet for this analysis is provided in Attachment 4.
Figure 5. Fecal coliform load duration curve for Mauvaise Terre Creek with
observed loads (triangles)
1.0E-02
1.0E-01
1.0E+00
1.0E+01
1.0E+02
1.0E+03
1.0E+04
1.0E+05
0 20 40 60 80 100
% Time Flow Exceeded
Nitrate load (kg/d)
1.00E+08
1.00E+09
1.00E+10
1.00E+11
1.00E+12
1.00E+13
1.00E+14
1.00E+15
0 20 40 60 80 100
% Time Flow Exceeded
Fecal Coliform Load (cfu/day)
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Fecal coliform concentration data are available for a wide range of flows and
exceedences are observed over the range of flows examined. This indicates that wet and
dry weather sources are significant contributors to fecal coliform exceedences in this
segment.
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6 TMDL DEVELOPMENT
This section presents the development of the total maximum daily load for the impaired
waterbodies in Mauvaise Terre Creek watershed. It begins with a description of how the
total loading capacity was calculated, and then describes how the loading capacity is
allocated among point sources, non-point sources, and the margin of safety. A discussion
of critical conditions and seasonality considerations is also provided.
6.1 PHOSPHORUS (MAUVAISE TERRE LAKE)
The BATHTUB model was developed to define the relationship between phosphorus
loads and resulting phosphorus concentrations in Mauvaise Terre Lake and to calculate
the loading capacity.
6.1.1 Calculation of Loading Capacity
The loading capacity is defined as the maximum pollutant load that a waterbody can
receive and still maintain compliance with water quality standards.
The loading capacity was determined by running the BATHTUB model repeatedly,
reducing the tributary nutrient concentrations for each simulation until model results
demonstrated attainment with the TMDL target. The maximum tributary concentration
that results in compliance with water quality standards was used as the basis for
determining the lake’s loading capacity. The tributary concentration was then converted
into a loading rate through multiplication with the tributary flow.
Initial BATHTUB load reduction simulations indicated that Mauvaise Terre Lake
phosphorus concentrations would exceed the water quality standard regardless of the
level of tributary load reduction, due to the elevated internal phosphorus loads from lake
sediments. This internal phosphorus flux is expected to decrease in the future in response
to external phosphorus load reductions, reverting back to more typical conditions. This
reduction in future sediment phosphorus release was represented in the model by
eliminating the additional sediment phosphorus source for scenarios where the tributary
phosphorus concentrations were less than 100 ug-P/l. The resulting tributary phosphorus
load that led to compliance with water quality standards was 60.8 kg-P/month (2.03 kg-
P/day). This allowable load corresponds to an approximately 57% reduction from
existing tributary loads (estimated as 142.8 kg-P/month or 4.76 kg-P/day). Loads are
expressed on a monthly basis because model results indicate that the phosphorus
residence time in Mauvaise Terre Lake is on the order of several weeks. Loads entering
the lake in the fall through early spring period do not directly affect summer phosphorus
concentrations, and therefore were excluded from the TMDL analysis.
6.1.2 Allocation
A TMDL consists of waste load allocations (WLAs) for point sources, load allocations
(LAs) for nonpoint sources, and a margin of safety (MOS). This definition is typically
illustrated by the following equation:
TMDL = WLA + LA + MOS
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Since no point sources are located in the Mauvaise Terre Lake watershed, the WLA will
be set to zero. The remainder of the loading capacity is given to the load allocation for
nonpoint sources and the margin of safety. The load allocation is not divided into
individual source categories for purposes of this TMDL, as it is the intent of the
implementation plan to provide detail on the contributions of specific sources to the
overall phosphorus load. Given a loading capacity of 60.8 kg-P/month (2.03 kg-P/day)
and an explicit margin of safety of 10% (discussed below) results in a load allocation for
Mauvaise Terre Lake of 54.72 kg-P/month (1.827 kg-P/day).
6.1.3 Critical Condition
TMDLs must take into account critical environmental conditions to ensure that the water
quality is protected during times when it is most vulnerable. Critical conditions were
taken into account in the development of this TMDL. The critical environmental
conditions for Mauvaise Terre Lake correspond to the middle to late summer period,
when observed phosphorus concentrations in the lake are highest. The BATHTUB model
simulations upon which this TMDL is based were conducted to represent this critical
middle to late summer period.
6.1.4 Seasonality
These TMDLs were conducted with an explicit consideration of seasonal variation. The
BATHTUB model was applied to evaluate phosphorus over a range of seasonal periods,
with TMDL results being based upon the most critical period as described above.
6.1.5 Margin of Safety
The phosphorus TMDL contains an explicit margin of safety of 10%. The 10% margin of
safety is considered an appropriate value based upon the generally good agreement
between the BATHTUB water quality model predicted values and the observed values.
Since the model reasonably reflects the conditions in the watershed, a 10% margin of
safety is considered to be adequate to address the uncertainty in the TMDL, based upon
the data available. The resulting explicit phosphorus load allocated to the margin of
safety is 6.08 kg-P/month (0.203 kg-P/day).
6.2 MANGANESE (MAUVAISE TERRE LAKE)
A load capacity calculation approach was applied to support development of a manganese
TMDL for Mauvaise Terre Lake.
6.2.1 Calculation of Loading Capacity
The loading capacity is defined as the maximum pollutant load that a waterbody can
receive and still maintain compliance with water quality standards. The loading capacity
was defined over a range of specified flows based on expected flows for the watershed.
The allowable loading capacity was computed by multiplying flow by the water quality
standard (150 ug/l for manganese). The manganese loading capacity is presented in Table
2. The percent reduction in manganese load was calculated by comparing the observed
and allowable manganese loads over a range of flows. The observed manganese load
was calculated from observed in-lake concentrations (averaged by flow class) and flows
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estimated from the Spring Creek gage near Springfield. A 53% reduction from current
manganese loads is required for Mauvaise Terre River flows less than 5 cfs.
Table 2. Manganese Loading Capacity
Mauvaise Terre
River Flow (cfs)
Manganese
Loading
Capacity
(kg/day)
0.5 0.18
1 0.37
2 0.73
5 1.84
10 3.67
20 7.34
30 11.01
40 14.68
50 18.35
6.2.2 Allocation
A TMDL consists of waste load allocations (WLAs) for point sources, load allocations
(Las) for nonpoint sources, and a margin of safety (MOS).
Because there are no point sources located in the Mauvaise Terre Lake watershed, the
WLA for manganese is set at zero. The remainder of the loading capacity is given to the
load allocation for nonpoint sources and the margin of safety (Table 3). The load
allocation is not divided into individual source categories for purposes of this TMDL, as
it is the intent of the implementation plan to provide detail on the contributions of
specific sources to the overall manganese load.
Table 3. Manganese TMDL Allocation1
Mauvaise
Terre River
Flow (cfs)
Manganese
Loading
Capacity
(kg/day)
Manganese
LA
(kg/day)
Manganese
MOS
(kg/day)
0.5 0.18 0.17 0.02
1 0.37 0.33 0.04
2 0.73 0.66 0.07
5 1.84 1.65 0.18
10 3.67 3.30 0.37
20 7.34 6.61 0.73
30 11.01 9.91 1.10
40 14.68 13.21 1.47
50 18.35 16.52 1.84
1 Due to rounding, numbers may not add up exactly.
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6.2.3 Critical Condition
TMDLs must take into account critical environmental conditions to ensure that the water
quality is protected during times when it is most vulnerable. Critical conditions were
taken into account in the development of this TMDL. Manganese naturally occurs in
soils; therefore, surface runoff contains manganese that is transported into the lake via
rain events. TMDL development based on the load duration curve approach considers
the entire range of flows that could occur in any given year; which includes flow from
rain events. Therefore critical conditions were addressed during TMDL development.
6.2.4 Seasonality
This TMDL was conducted with an explicit consideration of seasonal variation.
By specifying the allowable loading capacity as a function of stream flow, the
TMDL considers all possible seasonal variation.
6.2.5 Margin of Safety
Total maximum daily loads are required to contain a Margin of Safety (MOS) to account
for any uncertainty concerning the relationship between pollutant loading and receiving
water quality. The MOS can be either implicit (e.g., incorporated into the TMDL analysis
through conservative assumptions), or explicit (e.g., expressed in the TMDL as a portion
of the loading), or expressed as a combination of both. The manganese TMDL contains
an explicit margin of safety of 10% to address potential uncertainty in the effectiveness of
load reduction calculations. A relatively low margin of safety was chosen by IEPA
because the load duration curve (LDC) analysis, used to develop the loadings, provides
good information on the relationship between pollutant loadings and the receiving water
quality. The LDC method has few assumptions in it, compared to more complex models.
It provides a simple context for evaluating monitoring data across the entire range of flow
conditions (i.e. a period of 56 years from 1948-2004), thus reducing the uncertainty in the
flows (and related loads). Since duration curves calculated loads at various flows and
used the WQS as the TMDLs target, the method allowed IEPA to have a better
understanding of when the exceedences occurred in the waterbody and under what
conditions. This will help reduce uncertainty in the effectiveness of the implementation
efforts, and the likelihood of meeting the appropriate WQS/designated use.
6.3 NITRATE (MAUVAISE TERRE LAKE)
A load capacity calculation approach was applied to support development of a nitrate
TMDL for Mauvaise Terre Lake.
6.3.1 Calculation of Loading Capacity
The loading capacity is defined as the maximum pollutant load that a waterbody can
receive and still maintain compliance with water quality standards. The loading capacity
for nitrate was defined over a range of specified flows based on expected flows for the
watershed. The allowable loading capacity was computed by multiplying flow by the
water quality standard (10 mg-N/l for nitrate). The nitrate loading capacity is presented in
Table 4.
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The percent reduction in nitrate load was calculated by comparing the observed and
allowable nitrate loads over a range of flows. The observed nitrate load was calculated
from observed in-lake concentrations and flows estimated from the Spring Creek gage
near Springfield. To calculate the observed nitrate loads, the observed in-lake nitrate
concentrations were regressed against the flows and this relationship was applied to
calculate observed nitrate loads for the flows presented in Table 4. No reduction is
needed at lower watershed flows, as the observed load is less than the allowable loading
capacity. At higher flows (i.e., 50 cfs), a 57% reduction in nitrate is required.
Table 4. Nitrate Loading Capacity
Mauvaise Terre
River Flow
(cfs)
Nitrate Loading
Capacity (kg/day)
0.5 12.2
1 24.5
2 48.9
5 122.3
10 244.7
20 489.4
30 734.1
40 978.7
50 1,223.4
6.3.2 Allocation
A TMDL consists of waste load allocations (WLAs) for point sources, load allocations
(LAs) for nonpoint sources, and a margin of safety (MOS).
Because there are no point sources located in the Mauvaise Terre Lake watershed, the
WLA for nitrate is set at zero. The remainder of the loading capacity is given to the load
allocation for nonpoint sources and the margin of safety (Table 5). The load allocation is
not divided into individual source categories for purposes of this TMDL, as it is the intent
of the implementation plan to provide detail on the contributions of specific sources to
the overall nitrate load.
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Table 5. Nitrate TMDL Allocation1
Mauvaise
Terre River
Flow (cfs)
Nitrate
Loading
Capacity (kg-
N/day)
Nitrate
LA
(kg-N/day)
Nitrate
MOS
(kg-N/day)
0.5 12.2 11.0 1.2
1 24.5 22.0 2.4
2 48.9 44.0 4.9
5 122.3 110.1 12.2
10 244.7 220.2 24.5
20 489.4 440.4 48.9
30 734.1 660.6 73.4
40 978.7 880.9 97.9
50 1223.4 1101.1 122.3
1Due to rounding, numbers may not add up.
6.3.3 Critical Condition
TMDLs must take into account critical environmental conditions to ensure that the water
quality is protected during times when it is most vulnerable. Critical conditions were
taken into account in the development of this TMDL. Nitrate in this watershed was
shown to be significantly higher in spring. TMDL development based on the load
duration curve approach considers the entire range of flows that could occur in any given
year; which includes spring. Therefore critical conditions were addressed during TMDL
development.
6.3.4 Seasonality
This TMDL was conducted with an explicit consideration of seasonal variation.
By specifying the allowable loading capacity as a function of stream flow, the
TMDL considers all possible seasonal variation.
6.3.5 Margin of Safety
Total maximum daily loads are required to contain a Margin of Safety (MOS) to account
for any uncertainty concerning the relationship between pollutant loading and receiving
water quality. The MOS can be either implicit (e.g., incorporated into the TMDL analysis
through conservative assumptions), or explicit (e.g., expressed in the TMDL as a portion
of the loading), or expressed as a combination of both. The nitrate TMDL contains an
explicit margin of safety of 10% to address potential uncertainty in the effectiveness of
load reduction calculations. A relatively low margin of safety was chosen by IEPA
because the load duration curve (LDC) analysis, used to develop the loadings, provides
good information on the relationship between pollutant loadings and the receiving water
quality. The LDC method has few assumptions in it, compared to more complex models.
It provides a simple context for evaluating monitoring data across the entire range of flow
conditions (i.e. a period of 56 years from 1948-2004), thus reducing the uncertainty in the
flows (and related loads). Since duration curves calculated loads at various flows and
used the WQS as the TMDLs target, the method allowed IEPA to have a better
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understanding of when the exceedences occurred in the waterbody and under what
conditions.
6.4 FECAL COLIFORM (MAUVAISE TERRE CREEK)
A load capacity calculation approach was applied to support development of a fecal
coliform TMDL for Mauvaise Terre Creek.
6.4.1 Calculation of Loading Capacity
The loading capacity is defined as the maximum pollutant load that a waterbody can
receive and still maintain compliance with water quality standards. The loading capacity
was defined over the range of observed flow conditions. The allowable loading capacity
was computed by multiplying flow by the TMDL target (200 cfu/100 ml). The fecal
coliform loading capacity is presented in Table 6.
Table 6. Mauvaise Terre Creek Fecal Coliform Loading Capacity
Flow
Percentile
Range
Median
Observed
Mauvaise Terre
Creek Flow (cfs)
Load
Capacity
(cfu/day)1
60-100 1.56 7.63E+09
30-60 35.1 1.72E+11
0-30 139 6.81E+11
The maximum fecal coliform concentrations were examined for different flow intervals
(Table 7) and compared to the 200 cfu/100 ml target to estimate the percent reduction
needed to meet the water quality target. An approximately 99% reduction in fecal
coliform loading is required to meet the TMDL target over the range of flows observed in
the creek. Exceedances of the target were previously illustrated in Figure 5.
Table 7. Required Reductions in Existing Loads under Different Flow Conditions
Flow Percentile
Interval
Mauvaise Terre
Creek Flow (cfs)
Maximum fecal
concentration
(cfu/100 ml)
Percent
reduction to
meet target
60-100 0 - 14 110,000 99.8%
30-60 14 - 65 20,000 99.0%
0-30 65-6916 15,700 98.7%
6.4.2 Allocation
A TMDL consists of waste load allocations (WLAs) for point sources, load allocations
(LAs) for nonpoint sources, and a margin of safety (MOS). This definition is typically
illustrated by the following equation:
TMDL = WLA + LA + MOS
There are three NPDES permitted point source dischargers of fecal coliform in the
Mauvaise Terre Creek watershed. The WLA for these point sources was calculated using
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their permitted flow rates and a concentration consistent with meeting the TMDL target
(200 cfu/100 ml). Wasteload allocations for these facilities are presented in Table 8. The
total WLA for these three facilities equals 5.84E+10 using the design average flow
(DAF) and 1.17E+11 using the design maximum flow (DMF). The DAF WLA will be
used at average flow periods and the DMF WLA will be used at high flows. By
including the DMF, all flow periods that the facilities are permitted to discharge will be
represented in allocations.
In addition to the dischargers presented in Table 8, the Jacksonville STP also has a permit
for three combined sewer overflows (CSOs) that may discharge during wet weather:
outfalls 002, 003, and 004. The CSO WLA is based on the maximum primary treatment
capacity of 57.93 MGD that can discharge through outfall 004 and the average combined
discharge of 1.5 MGD from outfalls 002 and 003. The total WLA for the CSOs equals
4.5E+11 cfu/day and must not exceed an average of four overflow events per year. The
WLA and CSO WLA are based on the fecal coliform standard of 200 cfu/100 ml.
Table 8. Permitted Dischargers and WLAs
NPDES ID Facility Name Disinfection
Exemption
Design
Flow (MGD)
Flow Type
(MGD)
Permit
Expiration
WLA
(cfu/day)1
IL0055085 Marnico Village Year-round* 0.041
0.102
Average
Maximum
2-28-08 3.10E+08
7.72E+08
ILG580166 Chapin STP Year-round* 0.1
0.25
Average
Maximum
12-31-07 7.58E+08
1.89E+09
IL0021661 Jacksonville STP No 7.57
15
Average
Maximum
10-31-09 5.73E+10
1.14E+11
*These facilities will have the year-round disinfection exemption revoked and be granted a
seasonal exemption
5.84E+10
1.17E+11
The remainder of the loading capacity is given to the load allocation for nonpoint sources
as presented in Table 9. The load allocation is not divided into individual source
categories for purposes of this TMDL, as it is the intent of the implementation plan to
provide detail on the contributions of specific sources to the overall fecal coliform load.
Table 9. Fecal Coliform TMDL for Mauvaise Terre Creek (IL_DD-04)1
Flow
Percentile
Range
Median Obs.
Mauvaise
Terre Creek
Flow (cfs)
Load
Capacity
(cfu/day)
Observed
Load
(cfu/day)3
Wasteload
Allocation
(WLA)
(cfu/day)2
Estimated
CSO Load
(cfu/day)
CSO WLA
(cfu/day)4
Load
Allocation
(LA)
(cfu/day)
60-100 1.56 7.63E+09 5.99E+11 7.63E+09 0 0
30-60 35.1 1.72E+11 1.72E+13 5.84E+10 0 1.14E+11
0-30 139 6.81E+11 3.74E+14 1.17E+11 5.86E+11 4.5 E+11 1.14E+11
1 An implicit margin of safety is used in this TMDL
2 A lower WLA is used during the unique case where all of the stream flow is from the treatment
plant flow.
3 Observed load calculated using maximum fecal concentration and median observed flows
4 For purposes of this table, CSOs discharge only during high flows. The facility must meet their
long-term control plan requirements.
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Table 10. CSO Estimated Duration
Outfall MGD MG/hr Mean
(hr/yr) *
hr/day
002 CSO 34.3000 1.4292 5.0000 0.0139
004 CSO 3.7000 0.1542 121.6700 0.3380
*used average facility CSO data from 2003-2008. Outfall 003 did not discharge.
Table 11. Current CSO Estimated Wasteloads
CSO gal/hr L/gal ml/L cfu/ml hr/day cfu/day
Outfall 002‐ 1429166.6667 3.785 1000 2150 0.0139 1.62E+11
Outfall 004‐ 154166.6667 3.785 1000 2150 0.3380 4.24E+11
5.86E+11
Table 10 contains the estimated duration of discharge for outfalls 002 and 004. This
information was taken from Jacksonville Wastewater Treatment Plant’s Long Term
Control Plan- CSO Disinfection, October 2008. Please refer to Attachment 6 for this
document. Table 11 has the current CSO estimated wasteloads for outfalls 002 and 004.
A fecal coliform concentration of 215,000 cfu/100ml was used for the current estimated
CSO wasteloads. This is the median value from the EPA document- Report to Congress,
Impacts and Control of CSOs and SSOs (EPA 2004). The maximum wasteload allocation
from CSO outfalls is 4.5E+11 while the current estimate wasteload is 5.86E+11. A 23%
reduction in CSO loads is required during higher flows, when CSOs are discharging.
This percent reduction is based on the estimated CSO load and the CSO WLA. The
facility must comply with its permit and long-term control plan requirements.
Marnico Village and Chapin STP will have their year-round disinfection exemption
revoked and instead be granted seasonal disinfection exemptions. They will be expected
to meet the geometric mean of 200 cfu/100 ml during the months of May through
October at their outfall. Jacksonville STP outfall currently has the limit of 400 cfu/100 ml
and during permit renewal will be given a geometric mean of 200 cfu/100 ml.
Jacksonville STP is currently in compliance with their permit limit.
6.4.3 Critical Condition
TMDLs must take into account critical environmental conditions to ensure that the water
quality is protected during times when it is most vulnerable. Critical conditions were
taken into account in the development of this TMDL. The standard for fecal coliform
only applies during May 1 through October 31 when humans will be in contact with the
water. Water quality data and streamflow data from May 1 through October 31 were
used in the load duration curve. Therefore critical conditions were addressed during
TMDL development.
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6.4.4 Seasonality
This TMDL was conducted with an explicit consideration of seasonal variation. The
approach used for the TMDL evaluated seasonal loads because only May through
October water quality data were used in the analysis, consistent with the specification that
the standard only applies during this period. The fecal coliform standard will be met
regardless of flow conditions in the applicable season because the load capacity
calculations specify target loads for the entire range of flow conditions that are possible
to occur at any given point in the season where the standard applies.
6.4.5 Margin of Safety
Total maximum daily loads are required to contain a Margin of Safety (MOS) to account
for any uncertainty concerning the relationship between pollutant loading and receiving
water quality. The MOS can be either implicit (e.g., incorporated into the TMDL analysis
through conservative assumptions), or explicit (e.g., expressed in the TMDL as a portion
of the loading), or expressed as a combination of both. The fecal coliform TMDL
contains an implicit margin of safety, through the use of multiple conservative
assumptions. First, the TMDL target (no more than 200 cfu/100 ml at any point in time)
is more conservative than the more restrictive portion of the fecal coliform water quality
standard (geometric mean of 200 cfu/100 ml for all samples collected May through
October). An additional implicit Margin of Safety is provided via the use of a
conservative model to define load capacity. The model assumes no decay of bacteria that
enter the river, and therefore represents an upper bound of expected concentrations for a
given pollutant load. This margin of safety can be reviewed in the future as new data are
developed.
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7 PUBLIC PARTICIPATION AND INVOLVEMENT
The TMDL process included numerous opportunities for local watershed institutions and
the general public to be involved. The Agency and its consultant met with local
municipalities and agencies in Summer 2004 to notify stakeholders about the upcoming
TMDLs, and initiate the TMDL process. A number of phone calls were made to identify
and acquire data and information (see Stage 1 Report). As quarterly progress reports were
produced during the first stage of the TMDL process, the Agency posted them to their
website for public review.
In January 2005, a public meeting was announced for presentation of the Stage 1
findings. This announcement was mailed to everyone on the previous TMDL mailing list
and published in local newspapers. The public meeting was held at 6:30 pm on Tuesday,
March 1, 2005 at the Jacksonville Municipal Building in Jacksonville, Illinois. In
addition to the meeting's sponsors, nine (9) individuals attended the meeting. Attendees
registered and listened to an introduction to the TMDL Program from Illinois EPA and a
presentation on the Stage 1 findings by Limno-Tech, Inc. (LTI). This was followed by a
general question and answer session.
In July 2005, a public meeting was announced for presentation of the Stage 3 findings.
This announcement was mailed to everyone on the previous TMDL mailing list and
published in local newspapers. The public meeting was held at 6:00 pm on Wednesday,
July 26, 2006 at the Jacksonville Municipal Building in Jacksonville, Illinois. In addition
to the meeting's sponsors, nine (9) individuals attended the meeting. Attendees registered
and listened to a presentation on the Stage 3 findings by Limno-Tech, Inc. (LTI). This
was followed by a general question and answer session.
A responsiveness summary is included in Attachment 5. This responsiveness summary
addresses substantive questions and comments received during the public comment
period.
In August 2010, a public meeting was announced for the presentation of the Mauvaise
Terre Creek Watershed TMDL July 2010 Revision report. A public notice was sent to
individuals on the mailing list and published in the local newspaper. The meeting was
held at 2:00 pm on Tuesday, August 31, 2010 at the Jacksonville Municipal Building in
Jacksonville, Illinois. Eight individuals attended the meeting. The presentation included
all modifications to the original TMDL for the segment of Mauvaise Terre Creek (DD-
04). The public comment period ended September 30, 2010 and no comments were
received.
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8 ADAPTIVE IMPLEMENTATION PROCESS
The approach to be taken for TMDL implementation is based upon discussions with
Illinois EPA and its Scientific Advisory Committee. The approach consists of the
following steps:
1. Use existing data to define overall existing pollutant loads, as opposed to
developing a watershed model that might define individual loading sources.
2. Apply relatively simple models (e.g. BATHTUB) to define the load-response
relationship and define the maximum allowable pollutant load that the lake can
assimilate and still attain water quality standards
3. Compare the maximum allowable loading capacity to the existing load to define
the extent to which existing loads must be reduced in order to meet water quality
standards
4. Develop a voluntary implementation plan that includes both accountability and
the potential for adaptive management.
5. Carry out adaptive management through the implementation of a long-term
monitoring plan designed to assess the effectiveness of pollution controls as they
are implemented, as well as progress towards attaining water quality standards.
This approach is designed to accelerate the pace at which TMDLs are being developed
for sites dominated by nonpoint sources, which will allow implementation activities (and
water quality improvement) to begin sooner. The approach also places decisions on the
types of nonpoint source controls to be implemented at the local level, which will allow
those with the best local knowledge to prioritize sources and identify restoration
alternatives. Finally, the adaptive management approach to be followed recognizes that
models used for decision-making are approximations, and that there is never enough data
to completely remove uncertainty. The adaptive process allows decision-makers to
proceed with initial decisions based on modeling, and then to update these decisions as
experience and knowledge improve.
Steps 1-3 correspond to TMDL development and have been completed, as described in
Section 5 of this document. Steps 4 and 5 correspond to implementation.
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REFERENCES
Ernst, M. R., W. Frossard, and J. L. Mancini. 1994. Two Eutrophication Models make the
Grade. Water Environment and Technology 6 (11), pp 15-16.
Illinois Environmental Protection Agency (IEPA), 2006. Illinois Integrated Water Quality
Report and Section 303(d) list-2006. Illinois EPA Bureau of Water. April 2006.
IEPA/BOW/04-005 http://www.epa.state.il.us/water/watershed/reports/303d-report/
2006/303d-report.pdf
U.S. Environmental Protection Agency (EPA), 1991. Guidance for Water Quality-based
Decisions: The TMDL Process. EPA 440/4-91-001. Office of Water, Washington,
DC.
U.S. Environmental Protection Agency (EPA), 2004. Report to Congress, Impacts and
Control of CSOs and SSOs. EPA 833-R-04-001. Office of Water, Washington, DC.
Walker, W. W., 1985. Empirical Methods for Predicting Eutrophication in
Impoundments; Report 3, Phase III: Model Refinements. Technical Report E-81-9,
U.S. Army Engineer Waterways Experiment Station, Vicksburg, MS.
Attachment 1
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Mauvaise Terre Lake
Predicted & Observed Values Ranked Against CE Model Development Dataset
Segment: 4 Area-Wtd Mean
Predicted Values---> Observed Values--->
Variable Mean CV Rank Mean CV Rank
TOTAL P MG/M3 275.4 97.4% 277.1 97.4%
CHL-A MG/M3 63.4 99.3%
SECCHI M 0.3 4.0%
ANTILOG PC-1 5079.5 99.0%
ANTILOG PC-2 8.4 69.2%
TURBIDITY 1/M 2.1 91.7% 2.1 91.7%
ZMIX * TURBIDITY 2.8 44.0% 2.8 44.0%
ZMIX / SECCHI 5.4 58.0%
CHL-A * SECCHI 18.3 79.5%
CHL-A / TOTAL P 0.2 60.3%
FREQ(CHL-a>10) % 99.5 99.3%
FREQ(CHL-a>20) % 93.4 99.3%
FREQ(CHL-a>30) % 80.7 99.3%
FREQ(CHL-a>40) % 66.0 99.3%
FREQ(CHL-a>50) % 52.4 99.3%
FREQ(CHL-a>60) % 41.0 99.3%
CARLSON TSI-P 85.0 97.4% 85.1 97.4%
CARLSON TSI-CHLA 71.2 99.3%
CARLSON TSI-SEC 78.3 96.0%
Segment: 1 Near Dam
Predicted Values---> Observed Values--->
Variable Mean CV Rank Mean CV Rank
TOTAL P MG/M3 237.4 96.2% 260.0 97.0%
CHL-A MG/M3 68.0 99.5%
SECCHI M 0.3 6.6%
ANTILOG PC-1 4428.2 98.6%
ANTILOG PC-2 10.1 80.5%
TURBIDITY 1/M 1.2 78.4% 1.2 78.4%
ZMIX * TURBIDITY 2.7 41.6% 2.7 41.6%
ZMIX / SECCHI 6.4 69.5%
CHL-A * SECCHI 23.3 87.9%
CHL-A / TOTAL P 0.3 67.5%
FREQ(CHL-a>10) % 99.7 99.5%
FREQ(CHL-a>20) % 95.2 99.5%
FREQ(CHL-a>30) % 84.4 99.5%
FREQ(CHL-a>40) % 70.7 99.5%
FREQ(CHL-a>50) % 57.4 99.5%
FREQ(CHL-a>60) % 45.7 99.5%
CARLSON TSI-P 83.0 96.2% 84.3 97.0%
CARLSON TSI-CHLA 72.0 99.5%
CARLSON TSI-SEC 75.4 93.4%
Mauvaise Terre Lake
Predicted & Observed Values Ranked Against CE Model Development Dataset
Segment: 2 Middle
Predicted Values---> Observed Values--->
Variable Mean CV Rank Mean CV Rank
TOTAL P MG/M3 284.3 97.6% 250.0 96.7%
CHL-A MG/M3 53.0 98.8%
SECCHI M 0.3 2.8%
ANTILOG PC-1 4624.9 98.8%
ANTILOG PC-2 6.8 53.9%
TURBIDITY 1/M 2.6 95.1% 2.6 95.1%
ZMIX * TURBIDITY 3.4 54.6% 3.4 54.6%
ZMIX / SECCHI 5.2 55.9%
CHL-A * SECCHI 13.5 65.2%
CHL-A / TOTAL P 0.2 54.9%
FREQ(CHL-a>10) % 99.1 98.8%
FREQ(CHL-a>20) % 89.7 98.8%
FREQ(CHL-a>30) % 72.8 98.8%
FREQ(CHL-a>40) % 55.7 98.8%
FREQ(CHL-a>50) % 41.4 98.8%
FREQ(CHL-a>60) % 30.5 98.8%
CARLSON TSI-P 85.6 97.6% 83.8 96.7%
CARLSON TSI-CHLA 69.5 98.8%
CARLSON TSI-SEC 79.7 97.2%
Segment: 3 Upper Pool
Predicted Values---> Observed Values--->
Variable Mean CV Rank Mean CV Rank
TOTAL P MG/M3 355.4 98.7% 370.0 98.8%
CHL-A MG/M3 71.0 99.6%
SECCHI M 0.2 1.4%
ANTILOG PC-1 7556.6 99.6%
ANTILOG PC-2 6.9 55.2%
TURBIDITY 1/M 3.2 97.0% 3.2 97.0%
ZMIX * TURBIDITY 1.9 26.5% 1.9 26.5%
ZMIX / SECCHI 3.0 21.6%
CHL-A * SECCHI 14.3 68.5%
CHL-A / TOTAL P 0.2 48.7%
FREQ(CHL-a>10) % 99.8 99.6%
FREQ(CHL-a>20) % 95.8 99.6%
FREQ(CHL-a>30) % 86.0 99.6%
FREQ(CHL-a>40) % 73.1 99.6%
FREQ(CHL-a>50) % 60.1 99.6%
FREQ(CHL-a>60) % 48.5 99.6%
CARLSON TSI-P 88.8 98.7% 89.4 98.8%
CARLSON TSI-CHLA 72.4 99.6%
CARLSON TSI-SEC 83.0 98.6%
Mauvaise Terre Lake
Segment Mass Balance Based Upon Predicted Concentrations
Component: TOTAL P Segment: 1 Near Dam
Flow Flow Load Load Conc
Trib Type Location hm3/yr %Total kg/yr %Total mg/m3
1 1 Trib 1 1.2 10.3% 181.6 2.9% 155
PRECIPITATION 0.3 2.8% 9.5 0.2% 30
TRIBUTARY INFLOW 1.2 10.3% 181.6 2.9% 155
ADVECTIVE INFLOW 9.9 86.9% 2808.6 44.4% 284
NET DIFFUSIVE INFLOW 0.0 0.0% 3320.5 52.5%
***TOTAL INFLOW 11.4 100.0% 6320.2 100.0% 556
ADVECTIVE OUTFLOW 11.1 97.2% 2623.2 41.5% 237
***TOTAL OUTFLOW 11.1 97.2% 2623.2 41.5% 237
***EVAPORATION 0.3 2.8% 0.0 0.0%
***RETENTION 0.0 0.0% 3697.0 58.5%
Hyd. Residence Time = 0.0633 yrs
Overflow Rate = 34.8 m/yr
Mean Depth = 2.2 m
Component: TOTAL P Segment: 2 Middle
Flow Flow Load Load Conc
Trib Type Location hm3/yr %Total kg/yr %Total mg/m3
2 1 Trib 2 0.1 1.4% 21.7 0.4% 155
PRECIPITATION 0.2 2.3% 6.9 0.1% 30
TRIBUTARY INFLOW 0.1 1.4% 21.7 0.4% 155
ADVECTIVE INFLOW 9.7 96.3% 3461.3 67.6% 355
NET DIFFUSIVE INFLOW 0.0 0.0% 1629.8 31.8%
***TOTAL INFLOW 10.1 100.0% 5119.7 100.0% 506
ADVECTIVE OUTFLOW 9.9 97.7% 2808.6 54.9% 284
***TOTAL OUTFLOW 9.9 97.7% 2808.6 54.9% 284
***EVAPORATION 0.2 2.3% 0.0 0.0%
***RETENTION 0.0 0.0% 2311.1 45.1%
Hyd. Residence Time = 0.0309 yrs
Overflow Rate = 42.8 m/yr
Mean Depth = 1.3 m
Component: TOTAL P Segment: 3 Upper Pool
Flow Flow Load Load Conc
Trib Type Location hm3/yr %Total kg/yr %Total mg/m3
3 1 Trib 3 0.5 4.6% 69.9 0.7% 155
4 1 Trib 4 9.3 94.1% 1439.9 15.4% 155
PRECIPITATION 0.1 1.3% 3.8 0.0% 30
INTERNAL LOAD 0.0 0.0% 7808.5 83.8%
TRIBUTARY INFLOW 9.7 98.7% 1509.7 16.2% 155
***TOTAL INFLOW 9.9 100.0% 9322.0 100.0% 945
ADVECTIVE OUTFLOW 9.7 98.7% 3461.3 37.1% 355
NET DIFFUSIVE OUTFLOW 0.0 0.0% 4950.3 53.1%
***TOTAL OUTFLOW 9.7 98.7% 8411.6 90.2% 864
***EVAPORATION 0.1 1.3% 0.0 0.0%
***RETENTION 0.0 0.0% 910.4 9.8%
Hyd. Residence Time = 0.0079 yrs
Overflow Rate = 77.3 m/yr
Mean Depth = 0.6 m
Mauvaise Terre Lake
Overall Water & Nutrient Balances
Overall Water Balance Averaging Period = 0.08 years
Area Flow Variance CV Runoff
Trb Type Seg Name km2 hm3/yr (hm3/yr)2 - m/yr
1 1 1 Trib 1 9.4 1.2 0.00E+00 0.00 0.12
2 1 2 Trib 2 1.1 0.1 0.00E+00 0.00 0.12
3 1 3 Trib 3 3.6 0.5 0.00E+00 0.00 0.12
4 1 3 Trib 4 74.8 9.3 0.00E+00 0.00 0.12
PRECIPITATION 0.7 0.7 0.00E+00 0.00 1.02
TRIBUTARY INFLOW 89.0 11.1 0.00E+00 0.00 0.12
***TOTAL INFLOW 89.7 11.7 0.00E+00 0.00 0.13
ADVECTIVE OUTFLOW 89.7 11.1 0.00E+00 0.00 0.12
***TOTAL OUTFLOW 89.7 11.1 0.00E+00 0.00 0.12
***EVAPORATION 0.7 0.00E+00 0.00
Overall Mass Balance Based Upon Predicted Outflow & Reservoir Concentrations
Component: TOTAL P
Load Load Variance Conc Export
Trb Type Seg Name kg/yr %Total (kg/yr)2 %Total CV mg/m3 kg/km2/yr
1 1 1 Trib 1 181.6 1.9% 0.00E+00 0.00 155.0 19.2
2 1 2 Trib 2 21.7 0.2% 0.00E+00 0.00 155.0 19.2
3 1 3 Trib 3 69.9 0.7% 0.00E+00 0.00 155.0 19.3
4 1 3 Trib 4 1439.9 15.1% 0.00E+00 0.00 155.0 19.2
PRECIPITATION 20.3 0.2% 0.00E+00 0.00 29.5 30.0
INTERNAL LOAD 7808.5 81.8% 0.00E+00 0.00
TRIBUTARY INFLOW 1713.0 18.0% 0.00E+00 0.00 155.0 19.2
***TOTAL INFLOW 9541.8 100.0% 0.00E+00 0.00 812.9 106.4
ADVECTIVE OUTFLOW 2623.2 27.5% 0.00E+00 0.00 237.4 29.3
***TOTAL OUTFLOW 2623.2 27.5% 0.00E+00 0.00 237.4 29.3
***RETENTION 6918.6 72.5% 0.00E+00 0.00
Overflow Rate (m/yr) 16.4 Nutrient Resid. Time (yrs) 0.0312
Hydraulic Resid. Time (yrs) 0.0978 Turnover Ratio 2.7
Reservoir Conc (mg/m3) 275 Retention Coef. 0.725
Mauvaise Terre Lake
Hydraulic & Dispersion Parameters
Net Resid Overflow Dispersion-------->
Outflow Inflow Time Rate Velocity Estimated Numeric Exchange
Seg Name Seg hm3/yr years m/yr km/yr km2/yr km2/yr hm3/yr
1 Near Dam 0 11.1 0.0633 34.8 18.3 71.0 10.6 0.0
2 Middle 1 9.9 0.0309 42.8 26.6 167.0 10.9 70.8
3 Upper Pool 2 9.7 0.0079 77.3 86.2 448.2 29.3 69.6
Morphometry
Area Zmean Zmix Length Volume Width L/W
Seg Name km2 m m km hm3 km -
1 Near Dam 0.3 2.2 2.2 1.2 0.7 0.3 4.2
2 Middle 0.2 1.3 1.3 0.8 0.3 0.3 2.9
3 Upper Pool 0.1 0.6 0.6 0.7 0.1 0.2 3.7
Totals 0.7 1.6 1.1
Mauvaise Terre Lake
Segment & Tributary Network
--------Segment: 1 Near Dam
Outflow Segment: 0 Out of Reservoir
Tributary: 1 Trib 1 Type: Monitored Inflow
--------Segment: 2 Middle
Outflow Segment: 1 Near Dam
Tributary: 2 Trib 2 Type: Monitored Inflow
--------Segment: 3 Upper Pool
Outflow Segment: 2 Middle
Tributary: 3 Trib 3 Type: Monitored Inflow
Tributary: 4 Trib 4 Type: Monitored Inflow
Mauvaise Terre Lake
Description:
Single reservoir (172 acres)
3 segments
Global Variables Mean CV Model Options Code Description
Averaging Period (yrs) 0.0833 0.0 Conservative Substance 0 NOT COMPUTED
Precipitation (m) 0.0846 0.0 Phosphorus Balance 1 2ND ORDER, AVAIL P
Evaporation (m) 0.0846 0.0 Nitrogen Balance 0 NOT COMPUTED
Storage Increase (m) 0 0.0 Chlorophyll-a 0 NOT COMPUTED
Secchi Depth 0 NOT COMPUTED
Atmos. Loads (kg/km2-yr) Mean CV Dispersion 1 FISCHER-NUMERIC
Conserv. Substance 0 0.00 Phosphorus Calibration 2 CONCENTRATIONS
Total P 30 0.50 Nitrogen Calibration 0 NONE
Total N 1000 0.50 Error Analysis 0 NOT COMPUTED
Ortho P 15 0.50 Availability Factors 0 IGNORE
Inorganic N 500 0.50 Mass-Balance Tables 1 USE ESTIMATED CONCS
Output Destination 2 EXCEL WORKSHEET
Segment Morphometry Internal Loads ( mg/m2-day)
Outflow Area Depth Length Mixed Depth (m) Hypol Depth Non-Algal Turb (m-1) Conserv. Total P Total N
Seg Name Segment Group km2 m km Mean CV Mean CV Mean CV Mean CV Mean CV Mean CV
1 Near Dam 0 1 0.318 2.2 1.16 2.2 0 0 0 1.215452 0 0 0 0 0 0 0
2 Middle 1 1 0.231 1.32 0.82 1.32 0 0 0 2.612008 0 0 0 0 0 0 0
3 Upper Pool 2 1 0.126 0.61 0.68 0.61 0 0 0 3.175495 0 0 0 169.67 0 0 0
Segment Observed Water Quality
Conserv Total P (ppb) Total N (ppb) Chl-a (ppb) Secchi (m) Organic N (ppb) TP - Ortho P (ppb) HOD (ppb/day) MOD (ppb/day)
Seg Mean CV Mean CV Mean CV Mean CV Mean CV Mean CV Mean CV Mean CV Mean CV
1 0 0 260 0 0 0 68 0 0.343 0 0 0 0 0 0 0 0 0
2 0 0 250 0 0 0 53 0 0.254 0 0 0 0 0 0 0 0 0
3 0 0 370 0 0 0 71 0 0.202 0 0 0 0 0 0 0 0 0
Segment Calibration Factors
Dispersion Rate Total P (ppb) Total N (ppb) Chl-a (ppb) Secchi (m) Organic N (ppb) TP - Ortho P (ppb) HOD (ppb/day) MOD (ppb/day)
Seg Mean CV Mean CV Mean CV Mean CV Mean CV Mean CV Mean CV Mean CV Mean CV
1 1 0 1 0 1 0 1 0 1 0 1 0 1 0 1 0 1 0
2 1 0 1 0 1 0 1 0 1 0 1 0 1 0 1 0 1 0
3 1 0 1 0 1 0 1 0 1 0 1 0 1 0 1 0 1 0
Mauvaise Terre Lake
Tributary Data
Dr Area Flow (hm3/yr) Conserv. Total P (ppb) Total N (ppb) Ortho P (ppb) Inorganic N (ppb)
Trib Trib Name Segment Type km2 Mean CV Mean CV Mean CV Mean CV Mean CV Mean CV
1 Trib 1 1 1 9.431433 1.1713 0 0 0 155 0 0 0 0 0 0 0
2 Trib 2 2 1 1.130026 0.1403 0 0 0 155 0 0 0 0 0 0 0
3 Trib 3 3 1 3.630549 0.4509 0 0 0 155 0 0 0 0 0 0 0
4 Trib 4 3 1 74.80244 9.2894 0 0 0 155 0 0 0 0 0 0 0
Model Coefficients Mean CV
Dispersion Rate 1.000 0.70
Total Phosphorus 1.000 0.45
Total Nitrogen 1.000 0.55
Chl-a Model 1.000 0.26
Secchi Model 1.000 0.10
Organic N Model 1.000 0.12
TP-OP Model 1.000 0.15
HODv Model 1.000 0.15
MODv Model 1.000 0.22
Secchi/Chla Slope (m2/mg) 0.025 0.00
Minimum Qs (m/yr) 0.100 0.00
Chl-a Flushing Term 1.000 0.00
Chl-a Temporal CV 0.620 0
Avail. Factor - Total P 0.330 0
Avail. Factor - Ortho P 1.930 0
Avail. Factor - Total N 0.590 0
Avail. Factor - Inorganic N 0.790 0
Attachment 2
This page is blank to facilitate double sided printing.
Flow (cfs)
% of Time
Exceeded
Manganese load
(kg/day)
0.0 100.00 0.00 Observed Data
0.0 99.99 0.00 Date Flow (cfs) Mn (ug/l) Percentile
Manganese
load (kg/day)
0.0 99.45 0.00 4/11/2002 35.65 90 14.3 7.85
0.0 98.95 0.00 6/7/2002 17.66 67 27.9 2.90
0.0 98.45 0.00 7/10/2002 8.67 120 44.5 2.55
0.0 97.95 0.00 8/15/2002 3.53 220 59.6 1.90
0.0 97.45 0.00 10/17/2002 0.05 420 88.1 0.05
0.0 96.95 0.00
0.0 96.45 0.00
0.0 95.95 0.00
0.0 95.45 0.00
0.0 94.95 0.00
0.0 94.45 0.00
0.0 93.95 0.00
0.0 93.45 0.00
0.0 92.95 0.00
0.0 92.45 0.00
0.0 91.95 0.00
0.0 91.45 0.00
0.0 90.95 0.00
0.0 90.46 0.00
0.0 89.96 0.01
0.0 89.46 0.01
0.0 88.96 0.01
0.0 88.46 0.01
0.1 87.96 0.02
0.1 87.46 0.02
0.1 86.96 0.03
0.1 86.46 0.04
0.1 85.96 0.04
0.1 85.46 0.05
0.1 84.96 0.05
0.2 84.46 0.06
0.2 83.96 0.07
0.2 83.46 0.07
0.2 82.96 0.08
0.3 82.46 0.09
0.3 81.96 0.10
0.3 81.46 0.11
0.3 80.96 0.12
0.4 80.46 0.13
0.4 79.96 0.14
0.4 79.46 0.15
0.4 78.96 0.16
0.5 78.46 0.18
0.5 77.96 0.19
0.5 77.46 0.20
0.6 76.96 0.21
0.6 76.46 0.24
0.7 75.96 0.25
0.7 75.46 0.27
0.8 74.96 0.29
0.9 74.46 0.32
Data for Manganese Load Duration Curves
Flow (cfs)
% of Time
Exceeded
Manganese load
(kg/day)
Data for Manganese Load Duration Curves
0.9 73.96 0.34
1.0 73.46 0.37
1.1 72.96 0.39
1.1 72.47 0.41
1.2 71.97 0.44
1.3 71.47 0.46
1.3 70.97 0.49
1.4 70.47 0.52
1.5 69.97 0.54
1.6 69.47 0.59
1.7 68.97 0.61
1.7 68.47 0.64
1.8 67.97 0.67
1.9 67.47 0.71
2.0 66.97 0.73
2.1 66.47 0.77
2.2 65.97 0.80
2.3 65.47 0.84
2.4 64.97 0.87
2.5 64.47 0.92
2.6 63.97 0.94
2.7 63.47 1.00
2.9 62.97 1.05
3.0 62.47 1.10
3.1 61.97 1.14
3.2 61.47 1.18
3.2 60.97 1.18
3.5 60.47 1.30
3.5 59.97 1.30
3.9 59.47 1.41
3.9 58.97 1.41
4.2 58.47 1.53
4.2 57.97 1.53
4.5 57.47 1.65
4.5 56.97 1.65
4.5 56.47 1.65
4.8 55.97 1.77
4.8 55.47 1.77
5.1 54.97 1.89
5.1 54.48 1.89
5.5 53.98 2.00
5.8 53.48 2.12
5.8 52.98 2.12
6.1 52.48 2.24
6.1 51.98 2.24
6.4 51.48 2.36
6.4 50.98 2.36
6.7 50.48 2.47
6.7 49.98 2.47
7.1 49.48 2.59
7.1 48.98 2.59
7.4 48.48 2.71
7.4 47.98 2.71
7.7 47.48 2.83
7.7 46.98 2.83
Flow (cfs)
% of Time
Exceeded
Manganese load
(kg/day)
Data for Manganese Load Duration Curves
8.0 46.48 2.95
8.3 45.98 3.06
8.3 45.48 3.06
8.7 44.98 3.18
9.0 44.48 3.30
9.0 43.98 3.30
9.3 43.48 3.42
9.3 42.98 3.42
9.6 42.48 3.54
10.0 41.98 3.65
10.0 41.48 3.65
10.3 40.98 3.77
10.6 40.48 3.89
10.6 39.98 3.89
10.9 39.48 4.01
11.2 38.98 4.12
11.6 38.48 4.24
11.6 37.98 4.24
11.9 37.48 4.36
12.2 36.98 4.48
12.5 36.48 4.60
12.5 35.99 4.60
12.8 35.49 4.71
13.2 34.99 4.83
13.5 34.49 4.95
13.5 33.99 4.95
13.8 33.49 5.07
14.1 32.99 5.19
14.5 32.49 5.30
14.8 31.99 5.42
15.1 31.49 5.54
15.4 30.99 5.66
15.7 30.49 5.77
16.1 29.99 5.89
16.7 29.49 6.13
17.0 28.99 6.25
17.3 28.49 6.36
17.7 27.99 6.48
18.0 27.49 6.60
18.6 26.99 6.84
18.9 26.49 6.95
19.3 25.99 7.07
19.6 25.49 7.19
19.9 24.99 7.31
20.6 24.49 7.54
21.2 23.99 7.78
21.5 23.49 7.90
22.2 22.99 8.13
22.5 22.49 8.25
23.1 21.99 8.49
23.8 21.49 8.72
24.4 20.99 8.96
25.0 20.49 9.19
25.7 19.99 9.43
26.3 19.49 9.66
Flow (cfs)
% of Time
Exceeded
Manganese load
(kg/day)
Data for Manganese Load Duration Curves
27.3 18.99 10.02
27.9 18.49 10.25
28.6 18.00 10.49
29.2 17.50 10.72
30.5 17.00 11.20
31.5 16.50 11.55
32.4 16.00 11.90
33.4 15.50 12.26
34.4 15.00 12.61
35.3 14.50 12.96
36.6 14.00 13.43
37.9 13.50 13.91
39.2 13.00 14.38
40.5 12.50 14.85
41.7 12.00 15.32
43.4 11.50 15.91
45.0 11.00 16.50
46.9 10.50 17.21
48.8 10.00 17.91
50.7 9.50 18.62
53.3 9.00 19.56
55.6 8.50 20.39
58.1 8.00 21.33
61.0 7.50 22.39
64.2 7.00 23.57
68.4 6.50 25.10
72.6 6.00 26.63
77.7 5.50 28.52
83.5 5.00 30.64
90.2 4.50 33.12
97.6 4.00 35.83
108.9 3.50 39.95
122.0 3.00 44.78
137.4 2.50 50.44
157.4 2.00 57.75
188.8 1.50 69.29
231.5 1.00 84.97
321.1 0.50 117.85
1708.4 0.00 626.95
Attachment 3
This page is blank to facilitate double sided printing.
Data for Nitrate Load Duration Curves
Flow (cfs)
% of Time
Exceeded
Nitrate load
(kg/d)
0.0 100 0.00 Observed Data
0.0 100 0.00 Date Flow (cfs)
Nitrate
(mg/l) Percentile
Nitrate load
(kg/d)
0.0 99 0.00 4/15/1992 13.81 9.3 33.5 314.18
0.0 98 0.00 6/3/1992 7.39 1.3 47.8 23.49
0.0 98 0.00 7/2/1992 4.50 0.08 56.4 0.88
0.0 97 0.00 8/25/1992 0.00 0.01 91.3 0.00
0.0 97 0.00 4/11/2002 35.65 13 14.3 1133.69
0.0 96 0.00 6/7/2002 17.66 12 27.9 518.53
0.0 96 0.00 7/10/2002 8.67 6.68 44.5 141.70
0.0 95 0.00 8/15/2002 3.53 0.13 59.6 1.12
0.0 95 0.00
0.0 94 0.00
0.0 94 0.00
0.0 93 0.00
0.0 93 0.00
0.0 92 0.00
0.0 92 0.00
0.0 91 0.00
0.0 91 0.08
0.0 90 0.16
0.0 90 0.39
0.0 89 0.71
0.0 89 0.79
0.0 88 0.94
0.1 88 1.41
0.1 87 1.57
0.1 87 1.89
0.1 86 2.36
0.1 86 2.59
0.1 85 3.14
0.1 85 3.46
0.2 84 3.93
0.2 84 4.48
0.2 83 4.71
0.2 83 5.50
0.3 82 6.21
0.3 82 6.52
0.3 81 7.15
0.3 81 7.86
0.4 80 8.64
0.4 80 9.43
0.4 79 10.21
0.4 79 11.00
0.5 78 11.78
0.5 78 12.57
0.5 77 13.36
0.6 77 14.14
0.6 76 15.71
0.7 76 16.50
0.7 75 18.07
Data for Nitrate Load Duration Curves
Flow (cfs)
% of Time
Exceeded
Nitrate load
(kg/d)
0.8 75 19.64
0.9 74 21.21
0.9 74 22.78
1.0 73 24.36
1.1 73 25.93
1.1 72 27.50
1.2 72 29.07
1.3 71 30.64
1.3 71 33.00
1.4 70 34.57
1.5 70 36.14
1.6 69 39.28
1.7 69 40.85
1.7 68 42.43
1.8 68 44.78
1.9 67 47.14
2.0 67 48.71
2.1 66 51.07
2.2 66 53.42
2.3 65 55.78
2.4 65 58.14
2.5 64 61.28
2.6 64 62.85
2.7 63 66.78
2.9 63 69.92
3.0 62 73.07
3.1 62 76.21
3.2 61 78.56
3.2 61 78.56
3.5 60 86.42
3.5 60 86.42
3.9 59 94.28
3.9 59 94.28
4.2 58 102.13
4.2 58 102.13
4.5 57 109.99
4.5 57 109.99
4.5 56 109.99
4.8 56 117.85
4.8 55 117.85
5.1 55 125.70
5.1 54 125.70
5.5 54 133.56
5.8 53 141.42
5.8 53 141.42
6.1 52 149.27
6.1 52 149.27
6.4 51 157.13
6.4 51 157.13
6.7 50 164.99
6.7 50 164.99
7.1 49 172.84
Data for Nitrate Load Duration Curves
Flow (cfs)
% of Time
Exceeded
Nitrate load
(kg/d)
7.1 49 172.84
7.4 48 180.70
7.4 48 180.70
7.7 47 188.56
7.7 47 188.56
8.0 46 196.41
8.3 46 204.27
8.3 45 204.27
8.7 45 212.13
9.0 44 219.98
9.0 44 219.98
9.3 43 227.84
9.3 43 227.84
9.6 42 235.69
10.0 42 243.55
10.0 41 243.55
10.3 41 251.41
10.6 40 259.26
10.6 40 259.26
10.9 39 267.12
11.2 39 274.98
11.6 38 282.83
11.6 38 282.83
11.9 37 290.69
12.2 37 298.55
12.5 36 306.40
12.5 36 306.40
12.8 35 314.26
13.2 35 322.12
13.5 34 329.97
13.5 34 329.97
13.8 33 337.83
14.1 33 345.69
14.5 32 353.54
14.8 32 361.40
15.1 31 369.25
15.4 31 377.11
15.7 30 384.97
16.1 30 392.82
16.7 29 408.54
17.0 29 416.39
17.3 28 424.25
17.7 28 432.11
18.0 27 439.96
18.6 27 455.68
18.9 26 463.53
19.3 26 471.39
19.6 25 479.25
19.9 25 487.10
20.6 24 502.82
21.2 24 518.53
21.5 23 526.38
Data for Nitrate Load Duration Curves
Flow (cfs)
% of Time
Exceeded
Nitrate load
(kg/d)
22.2 23 542.10
22.5 22 549.95
23.1 22 565.67
23.8 21 581.38
24.4 21 597.09
25.0 20 612.81
25.7 20 628.52
26.3 19 644.23
27.3 19 667.80
27.9 18 683.51
28.6 18 699.23
29.2 17 714.94
30.5 17 746.37
31.5 16 769.94
32.4 16 793.51
33.4 15 817.07
34.4 15 840.64
35.3 14 864.21
36.6 14 895.64
37.9 13 927.07
39.2 13 958.49
40.5 12 989.92
41.7 12 1021.34
43.4 11 1060.63
45.0 11 1099.91
46.9 10 1147.05
48.8 10 1194.19
50.7 9 1241.33
53.3 9 1304.18
55.6 9 1359.17
58.1 8 1422.02
61.0 8 1492.73
64.2 7 1571.30
68.4 7 1673.43
72.6 6 1775.57
77.7 6 1901.27
83.5 5 2042.69
90.2 5 2207.67
97.6 4 2388.37
108.9 4 2663.35
122.0 3 2985.47
137.4 3 3362.58
157.4 2 3849.68
188.8 2 4619.61
231.5 1 5664.53
321.1 1 7856.49
1708.4 0 41796.51
Attachment 4
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Data for Fecal Coliform Load Duration Curves
Flow (cfs)
% of Time
Exceeded Load (cfu/day)
0.0 100.00 0.00E+00 Observed Data
0.0 99.99 0.00E+00 Date Flow (cfs)
Fecal coliform
(cfu/100 ml) Percentile Load (cfu/day)
0.0 99.45 0.00E+00 5/31/1990 20.80 500 54.5 2.54E+11
0.0 98.95 0.00E+00 7/12/1990 167.70 11000 12.1 4.51E+13
0.0 98.45 0.00E+00 8/23/1990 37.70 6200 43.0 5.72E+12
0.0 97.95 0.00E+00 10/10/1990 24.70 20000 51.6 1.21E+13
0.0 97.45 0.00E+00 5/2/1991 16.90 2400 57.5 9.92E+11
0.0 96.95 0.00E+00 5/30/1991 0.14 110000 88.5 3.85E+11
0.0 96.45 0.00E+00 7/8/1991 6.63 600 69.0 9.73E+10
0.0 95.95 0.00E+00 8/27/1991 54.60 1400 33.9 1.87E+12
0.0 95.45 0.00E+00 10/2/1991 4.29 650 72.8 6.82E+10
0.0 94.95 0.00E+00 6/2/1992 241.80 410 7.7 2.43E+12
0.0 94.45 0.00E+00 7/20/1992 7.02 2040 68.4 3.50E+11
0.0 93.95 0.00E+00 8/18/1992 11.57 700 62.9 1.98E+11
0.0 93.45 0.00E+00 9/17/1992 24.70 760 51.6 4.59E+11
0.0 92.95 0.00E+00 10/28/1992 0.17 140 88.3 5.79E+08
0.0 92.45 0.00E+00 5/6/1993 3.12 360 75.0 2.75E+10
0.0 91.95 0.00E+00 6/3/1993 67.60 430 29.1 7.11E+11
0.0 91.45 0.00E+00 8/9/1993 28.60 420 48.6 2.94E+11
0.0 90.95 1.27E+08 9/16/1993 35.10 2800 44.5 2.40E+12
0.0 90.46 2.54E+08 5/11/1994 3.12 440 75.0 3.36E+10
0.1 89.96 6.36E+08 6/23/1994 18.20 540 56.4 2.40E+11
0.1 89.46 1.15E+09 7/27/1994 10.92 280 63.5 7.48E+10
0.1 88.96 1.27E+09 9/14/1994 42.90 3500 39.9 3.67E+12
0.2 88.46 1.53E+09 10/20/1994 2.60 1200 76.2 7.63E+10
0.2 87.96 2.29E+09 5/4/1995 0.00 400 91.3 0.00E+00
0.3 87.46 2.54E+09 6/21/1995 6.24 12000 69.6 1.83E+12
0.3 86.96 3.05E+09 9/7/1995 36.40 3500 43.7 3.12E+12
0.4 86.46 3.82E+09 9/25/1995 45.50 920 38.5 1.02E+12
0.4 85.96 4.20E+09 5/15/1996 8.45 900 66.4 1.86E+11
0.5 85.46 5.09E+09 7/1/1996 65.00 1400 29.9 2.23E+12
0.6 84.96 5.60E+09 8/12/1996 23.40 440 52.5 2.52E+11
0.7 84.46 6.36E+09 9/4/1996 422.50 280 3.6 2.89E+12
0.7 83.96 7.25E+09 5/12/1997 5.59 820 70.6 1.12E+11
0.8 83.46 7.63E+09 6/23/1997 0.00 1000 91.3 0.00E+00
0.9 82.96 8.91E+09 8/12/1997 236.60 1750 7.9 1.01E+13
1.0 82.46 1.01E+10 9/22/1997 65.00 1300 29.9 2.07E+12
1.1 81.96 1.06E+10 7/6/1998 53.30 660 34.6 8.61E+11
1.2 81.46 1.16E+10 9/30/1998 66.30 1600 29.5 2.60E+12
1.3 80.96 1.27E+10 10/25/2001 28.60 400 48.6 2.80E+11
1.4 80.46 1.40E+10 5/14/2002 92.30 2200 22.2 4.97E+12
1.6 79.96 1.53E+10 7/8/2002 24.70 360 51.6 2.18E+11
1.7 79.46 1.65E+10 8/1/2002 45.50 320 38.5 3.56E+11
1.8 78.96 1.78E+10 9/16/2002 390.00 15700 4.1 1.50E+14
2.0 78.46 1.91E+10 10/24/2002 132.60 140 15.7 4.54E+11
2.1 77.96 2.04E+10 7/2/2003 13.00 780 60.7 2.48E+11
2.2 77.46 2.16E+10 8/7/2003 107.90 640 19.3 1.69E+12
2.3 76.96 2.29E+10 9/17/2003 884.00 485 1.1 1.05E+13
2.6 76.46 2.54E+10 5/4/2004 1.05 330 82.1 8.50E+09
2.7 75.96 2.67E+10 6/1/2004 23.40 1600 52.5 9.16E+11
3.0 75.46 2.93E+10 6/30/2004 45.50 700 38.5 7.79E+11
3.3 74.96 3.18E+10
3.5 74.46 3.44E+10
3.8 73.96 3.69E+10
4.0 73.46 3.94E+10
Data for Fecal Coliform Load Duration Curves
Flow (cfs)
% of Time
Exceeded Load (cfu/day)
4.3 72.96 4.20E+10
4.6 72.47 4.45E+10
4.8 71.97 4.71E+10
5.1 71.47 4.96E+10
5.5 70.97 5.34E+10
5.7 70.47 5.60E+10
6.0 69.97 5.85E+10
6.5 69.47 6.36E+10
6.8 68.97 6.62E+10
7.0 68.47 6.87E+10
7.4 67.97 7.25E+10
7.8 67.47 7.63E+10
8.1 66.97 7.89E+10
8.5 66.47 8.27E+10
8.8 65.97 8.65E+10
9.2 65.47 9.03E+10
9.6 64.97 9.42E+10
10.1 64.47 9.92E+10
10.4 63.97 1.02E+11
11.1 63.47 1.08E+11
11.6 62.97 1.13E+11
12.1 62.47 1.18E+11
12.6 61.97 1.23E+11
13.0 61.47 1.27E+11
13.0 60.97 1.27E+11
14.3 60.47 1.40E+11
14.3 59.97 1.40E+11
15.6 59.47 1.53E+11
15.6 58.97 1.53E+11
16.9 58.47 1.65E+11
16.9 57.97 1.65E+11
18.2 57.47 1.78E+11
18.2 56.97 1.78E+11
18.2 56.47 1.78E+11
19.5 55.97 1.91E+11
19.5 55.47 1.91E+11
20.8 54.97 2.04E+11
20.8 54.48 2.04E+11
22.1 53.98 2.16E+11
23.4 53.48 2.29E+11
23.4 52.98 2.29E+11
24.7 52.48 2.42E+11
24.7 51.98 2.42E+11
26.0 51.48 2.54E+11
26.0 50.98 2.54E+11
27.3 50.48 2.67E+11
27.3 49.98 2.67E+11
28.6 49.48 2.80E+11
28.6 48.98 2.80E+11
29.9 48.48 2.93E+11
29.9 47.98 2.93E+11
31.2 47.48 3.05E+11
31.2 46.98 3.05E+11
32.5 46.48 3.18E+11
33.8 45.98 3.31E+11
33.8 45.48 3.31E+11
35.1 44.98 3.44E+11
Data for Fecal Coliform Load Duration Curves
Flow (cfs)
% of Time
Exceeded Load (cfu/day)
36.4 44.48 3.56E+11
36.4 43.98 3.56E+11
37.7 43.48 3.69E+11
37.7 42.98 3.69E+11
39.0 42.48 3.82E+11
40.3 41.98 3.94E+11
40.3 41.48 3.94E+11
41.6 40.98 4.07E+11
42.9 40.48 4.20E+11
42.9 39.98 4.20E+11
44.2 39.48 4.33E+11
45.5 38.98 4.45E+11
46.8 38.48 4.58E+11
46.8 37.98 4.58E+11
48.1 37.48 4.71E+11
49.4 36.98 4.83E+11
50.7 36.48 4.96E+11
50.7 35.99 4.96E+11
52.0 35.49 5.09E+11
53.3 34.99 5.22E+11
54.6 34.49 5.34E+11
54.6 33.99 5.34E+11
55.9 33.49 5.47E+11
57.2 32.99 5.60E+11
58.5 32.49 5.73E+11
59.8 31.99 5.85E+11
61.1 31.49 5.98E+11
62.4 30.99 6.11E+11
63.7 30.49 6.23E+11
65.0 29.99 6.36E+11
67.6 29.49 6.62E+11
68.9 28.99 6.74E+11
70.2 28.49 6.87E+11
71.5 27.99 7.00E+11
72.8 27.49 7.13E+11
75.4 26.99 7.38E+11
76.7 26.49 7.51E+11
78.0 25.99 7.63E+11
79.3 25.49 7.76E+11
80.6 24.99 7.89E+11
83.2 24.49 8.14E+11
85.8 23.99 8.40E+11
87.1 23.49 8.52E+11
89.7 22.99 8.78E+11
91.0 22.49 8.91E+11
93.6 21.99 9.16E+11
96.2 21.49 9.42E+11
98.8 20.99 9.67E+11
101.4 20.49 9.92E+11
104.0 19.99 1.02E+12
106.6 19.49 1.04E+12
110.5 18.99 1.08E+12
113.1 18.49 1.11E+12
115.7 18.00 1.13E+12
118.3 17.50 1.16E+12
123.5 17.00 1.21E+12
127.4 16.50 1.25E+12
Data for Fecal Coliform Load Duration Curves
Flow (cfs)
% of Time
Exceeded Load (cfu/day)
131.3 16.00 1.29E+12
135.2 15.50 1.32E+12
139.1 15.00 1.36E+12
143.0 14.50 1.40E+12
148.2 14.00 1.45E+12
153.4 13.50 1.50E+12
158.6 13.00 1.55E+12
163.8 12.50 1.60E+12
169.0 12.00 1.65E+12
175.5 11.50 1.72E+12
182.0 11.00 1.78E+12
189.8 10.50 1.86E+12
197.6 10.00 1.93E+12
205.4 9.50 2.01E+12
215.8 9.00 2.11E+12
224.9 8.50 2.20E+12
235.3 8.00 2.30E+12
247.0 7.50 2.42E+12
260.0 7.00 2.54E+12
276.9 6.50 2.71E+12
293.8 6.00 2.88E+12
314.6 5.50 3.08E+12
338.0 5.00 3.31E+12
365.3 4.50 3.58E+12
395.2 4.00 3.87E+12
440.7 3.50 4.31E+12
494.0 3.00 4.83E+12
556.4 2.50 5.45E+12
637.0 2.00 6.23E+12
764.4 1.50 7.48E+12
937.3 1.00 9.17E+12
1300.0 0.50 1.27E+13
6916.0 0.00 6.77E+13
Attachment 5
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Attachment 5-1
Mauvaise Terre Responsiveness Summary
1. During the presentation, it was stated that the computer model BATHTUB used for
Mauvaise Terre Lake indicated that “internal” phosphorus loading from sediment was the
primary source (of phosphorus?). It was stated that the external (tributary) phosphorus
loads were quantified using a scenario where internal loading was not occurring. Could
you please indicate what percentage of the potential phosphorus load is external versus
internal loading? I assume that the release of phosphorus from the lake sediment would
occur only when the oxygen is depleted in the lake. How often or how severe is the
oxygen depleted within the lake? Are there any trends?
Response: Internal phosphorus loading from the bottom sediments is the primary source of
phosphorus to the water column. Model results indicate 18% of the phosphorus load is
from external sources and 82 % from an internal source. Phosphorus data collected at
different water depths show higher concentrations of phosphorus near the lake bottom.
Mauvaise Terre Lake is shallow and dissolved oxygen does not approach zero at any of
the three monitoring stations (data collected in1992, 1993 and 2005). The higher
phosphorus concentrations measured deeper in the water column suggest resuspension of
in-place sediments as a source. The range of phosphorus concentrations measured over
12 years is constant; no trends were observed.
2. During the presentation, a question from the public was received regarding the number of
sample points (and locations) related to fecal coliform. Please confirm that there was
only one sampling station 1.5 miles Northeast of Merritt used for fecal coliform with
approximately 45 samples collected during the summer months between 1990 through
2004. It is my understanding that the load duration curve for Mauvaise Terre Creek was
established using flows from Spring Creek (near Springfield) since there are no flow data
available for Mauvaise Terre Creek at the single sampling point. It did not seem like
there was much difference between low flow and high flow conditions. Is there a
quantitative correlation between the City’s CSO discharges (presumably occurring during
high flow conditions) and the sampling of data points for fecal coliform? There seems to
be several potential sources of fecal coliform contamination upstream of the sampling
point near Merritt.
Response: Data collected at the sampling station 1.5 miles Northeast of Merritt was used to
develop the load duration curve. 49 samples collected at this location between May and
October were used for the load duration curve. The dataset covered the period May 1990
to June 2004. You are correct that flows were not available for Mauvaise Terre Creek
and that flows measured on Spring Creek were used to synthesize a flow record for
Mauvaise Terre Creek. As part of the Stage 1 report, potential sources of fecal coliform
were identified and included CSOs, livestock operations, municipal sewage disposal,
private sewage disposal systems and runoff from manure-fertilized cropland. We do not
have instream fecal coliform measurements collected on the same date of the known
occurrence of CSOs. While we do have monthly DMR data that summarizes whether a
CSO occurred in a given month, we do not have information on which day(s) of the
month the overflow occurred. Such data could be obtained and analyzed to see if there
was a trend towards higher instream concentrations during periods of CSO discharge.
Attachment 5-2
This information would be useful, but not necessarily conclusive because it does not take
into consideration the effect that wet weather has on other potential sources.
3. During the presentation in July, it was stated that one sampling point for fecal coliform
was used in Mauvaise Terre Creek near Exeter. I wonder if additional monitoring points
would be advisable; perhaps both upstream and downstream of the Jacksonville
Wastewater Treatment Plants, and during high and low water conditions.
Response: A Plan of Study for CSO Assessment has been submitted to the Agency by the
City of Jacksonville. In this plan, the city proposes monitoring for fecal coliform and E.
coli during dry and wet weather both upstream and downstream of CSO discharges. The
Agency is currently reviewing this plan with the goal of having an approved monitoring
plan so that monitoring can be done during the spring of 2007.
4. Mauvaise Terre Lake is a secondary public water supply source for the city. Does the
standard still apply when we do not use this source often?
Response: Yes, the standard still applies. If there is the potential for the city to use this
water for drinking water purposes, the public water supply standard applies.
5. The City is working with the Army Corps of Engineers for a dredging project on
Mauvaise Terre Lake. We are attempting to develop a plan to dredge, or otherwise
remove, some of the approximately 2.1 million cubic yards of silt, which has
accumulated in the lake. I wonder how the City’s plans to remove silt from the Lake
Mauvaise Terre would affect the TMDL study for that body of water. Should we be
working with Illinois EPA on this project and keep you informed? We have been setting
aside money for dredging for the last fifteen years. The Army Corps has done a
preliminary study, but they have not informed us if they are going to continue on. We
really want to get this project done and would like to know if the state can contribute
some funds toward this.
Response: In the TMDL Report, we state that “the lake phosphorus concentrations would
still exceed the water quality standard regardless of reducing the tributary load due to
elevated internal phosphorus loads from lake sediment. This internal phosphorus flux is
expected to decrease in the future in response to external phosphorus load reductions,
reverting back to more typical conditions.” This can be a long process and while
dredging takes care of the internal phosphorus load, it does not decrease the external load
which caused the internal load to begin with. If the external load is not reduced, the
internal source would build up once again. Illinois EPA does have 319 Nonpont Source
funds to use for projects in watersheds. Because of the high costs of dredging, 319 funds
are rarely used for this kind of work. 319 funds can be used on projects in the watershed
to reduce runoff (external loads). More information on 319 funds and other
implementation activities will be available in the Implementation Plan. Another meeting
will be held in the watershed to discuss this. If you would like any information on the
319 program before this meeting, please call the Illinois EPA 319 Coordinator, Amy
Walkenbach, at 217/782-3362.
Attachment 5-3
6. One of the sources of fecal coliform could be septic system failures. How are you going
to deal with septic problems?
Response: Household septic systems are currently regulated by the Illinois Department of
Public Health and local health departments. In the TMDL Implementation Plan, we will
work with these entities to provide information on septic system evaluation, testing and
maintenance. If you are aware of any failures or have any questions on failing septic
systems, please contact your local county health department for information. Call the
Illinois Department of Public Health at (217) 782-4977 or go the website at
http://www.idph.state.il.us/local/alpha.htm for county health department websites and
phone numbers.
7. Is there any concern for a rural landowner who is trying to build in this watershed and
add to the septic load? Does the health department check these septic systems?
Response: Individual septic systems are regulated by the Illinois Department of Public
Health through local health departments. Landowners are required to comply with the
regulations and ordinances of these entities. Permitting and inspections of these systems
are performed by the local health department. Sewage treatment facilities with a surface
discharge are required by federal law to obtain an NPDES issued by Illinois
Environmental Protection Agency. Properly designed, maintained and operated septic
systems should not increase the fecal coliform load to nearby streams.
Attachment 5-4
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Attachment 6
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Long Term Control Plan – CSO Disinfection
Jacksonville Wastewater Treatment Plant
Jacksonville, IL
Prepared For:
City of Jacksonville
200 West Douglas Ave.
Jacksonville, IL 62650
Prepared By: Sub-Consultant:
Benton & Associates, Inc. Camp, Dresser, & McKee
1970 West Lafayette, Ave 100 North Tucker, Suite 550
Jacksonville, IL 62650 St. Louis, MO 63101
October 2008
Long Term Control Plan – CSO Disinfection
Jacksonville, IL
TABLE OF CONTENTS
Section Page
1.0 Introduction ..................................................................................... 1
2.0 Characterization, Monitoring, & Modeling ....................................... 3
3.0 Public Participation ......................................................................... 19
4.0 Consideration of Sensitive Areas .................................................... 21
5.0 Evaluation of Alternatives ............................................................... 21
6.0 Cost/Performance Considerations .................................................. 23
7.0 Operational Plan ............................................................................. 25
8.0 Maximizing Treatment at the Treatment Plant ................................ 26
9.0 Implementation Schedule ............................................................... 27
10.0 Post-Construction Compliance Monitoring Program ..................... 28
Appendix A
NPDES Permit IL0021661 ..................................................................... A-1
Appendix B
Plan of Study for CSO Assessment ....................................................... B-1
Appendix C
Agency Correspondence ....................................................................... C-1
Appendix D
City of Jacksonville – CSS & CSO Facilities .......................................... D-1
Appendix E
Evaluation of CSO Disinfection Alternatives .......................................... E-1
Appendix F
CSO Discharge Data ............................................................................. F-1
Long Term Control Plan – CSO Disinfection
Jacksonville, IL
1
1.0 Introduction
NPDES Permit No. IL00216611 issued on September 29, 2004 contained modifications that
included provisions for the City of Jacksonville (City) to develop and implement a CSO Control
Plan (Appendix A). The City submitted a CSO Plan of Study (POS) to the IEPA on April 29,
20052 (Appendix B). During the review of the CSO POS, the Total Maximum Daily Load
(TMDL) for Mauvaise Terre Creek was finalized3. The TMDL listed the creek for excessive
levels of fecal coliform and provided a load allocation for the City’s CSO discharges of 5.72 x
1010 colony forming units (cfu) of fecal coliform per day. A review letter received November 29,
20064 from IEPA indicated that the TMDL findings should be incorporated in the POS. Upon
receipt of this review letter the City, Engineers, and IEPA representatives met on January 19th,
2007 to discuss further refinement of the POS and potential alternatives to meet the TMDL limits
in Mauvaise Terre Creek for fecal coliform (see Appendix C for IEPA Correspondence). The
major result from this meeting was the City’s decision to forgo the completion of the POS and
proceed directly with a Long Term Control Plan (LTCP) with emphasis on fecal coliform. This
approach was formally approved by IEPA in an August 8, 2007 letter5.
The following paragraph provides a summary of the CSO facilities previously provided in the
POS. The City owns and operates a combined sewer system that contains three points that
discharge to Mauvaise Terre Creek. A description of the discharges is given below:
􀂃􈌠 002: “North” CSO Pump Station
􀂃􈌠 003: “East” / Johnson St. CSO Pump Station
􀂃􈌠 004: POTW Discharge – covered under the City’s NPDES Permit, the flow enters
Mauvaise Terre Creek either by gravity or pumped after receiving primary treatment –
total capacity = 57.9 mgd.
Figure 1.0 on the following page shows the CSO facilities located within the City’s Publicly
Owned Treatment Works (POTW). In addition to these facilities, and as described in the POS,
the Johnson St. CSO Pumping Station contains a CSO discharge (004) and under normal
operations (all but extreme flooding conditions) combined sewage is either pumped or flows by
gravity to the POTW.
1 NPDES Permit No. IL0021661 – Effective Date: 11/01/04, Expiration Date: 10/31/09
2 Mauvaise Terre Creek TMDL Report – August 2007
3 Plan of Study for CSO Assessment – CDM, April 2005
4 IEPA Letter from Mr. Garretson – November 29, 2006 RE: POS for CSO Assessment
5 IEPA Letter from Mr. Garretson – January 25, 2007 RE: POS for CSO Assessment
Long Term Control Plan – CSO Disinfection
Jacksonville, IL
2
Figure 1.0 – City CSO Facilities @ POTW
In accordance with USEPA Guidelines6 and as described in the current IEPA NPDES Permit,
the following sections of this LTCP contain the required nine elements (listed below):
􀂃􈌠 Characterization, Monitoring, & Modeling
􀂃􈌠 Public Participation
􀂃􈌠 Consideration of Sensitive Areas
􀂃􈌠 Evaluation of Alternatives
􀂃􈌠 Cost/Performance Considerations
􀂃􈌠 Operational Plan
􀂃􈌠 Maximizing Treatment at the Treatment Plant
􀂃􈌠 Implementation Schedule
􀂃􈌠 Post-Construction Compliance Monitoring Program
6 Combined Sewer Overflows: Guidance for Long-Term Control – September 1995
CSO CLARIFIER
NORTH
NTS
NORTH FIRST
FLUSH BASIN
002
004
SPLITTER
96 INCH OUTFALL TO MAUVAISE TERRE CREEK
EAST FIRST
FLUSH BASIN
EXTENDED AERATION WWTP
001
CSO FACILITIES
Long Term Control Plan – CSO Disinfection
Jacksonville, IL
3
2.0 Characterization, Monitoring, & Modeling
The City operates a well maintained Combined Sewer System (CSS) and has taken a proactive
approach in reducing CSO events. Through close coordination with the IEPA, the City has
successfully implemented the Nine Minimum Controls (NMC) and continues an aggressive
stormwater separation program. The City of Jacksonville has made significant capital
investments for treating & managing its CSO flows, including a major investment at the onset in
the 1988/1990 timeframe when the three CSO outfalls were constructed.
The City has continued to maintain its commitment to reducing CSO overflows and has invested
significant capital in storm separation projects throughout the Community. A summary of the
storm separation projects7 and their capital costs as constructed over the past decade is
presented in Table 2.0 below:
Storm Separation
Project
Implementation
Timeframe
Capital Cost
Church St. Phase I 1997/98 $640,000
Walnut St. Phase I 1998/99 $285,000
Town Brook Relief 1999/2000 $710,000
Walnut St. Phase II 2001/02 $1,100,000
Church St. Phase II 2006/07 $445,000
Table 2.0 – City Major Stormwater Separation Projects
2.1 Facilities Description
As part of the System Characterization and understanding of the CSS, a thorough description of
the CSO Facilities (facility capacities and operations) is provided herein. The City CSO facilities
are unique in that the two remote CSO outfalls (002 & 003) discharge by pumping only.
Additionally, the main CSO outfall, 004, is monitored in accordance with the NPDES Permit.
Therefore, for every overflow event, the City has a record of event duration and can estimate
the volu