final bessey creek fecal coliform tmdl - amazon s3€¦ · fecal coliform concentrations from...

TOTAL MAXIMUM DAILY LOAD (TMDL)

For Fecal Coliform

In Bessey Creek (WBID 3211)

Prepared by:

US EPA Region 4 61 Forsyth Street SW

Atlanta, Georgia 30303

January 2009

In compliance with the provisions of the Federal Clean Water Act, 33 U.S.C §1251 et. seq., as amended by the Water Quality Act of 1987, P.L. 400-4, the U.S. Environmental Protection Agency is hereby establishing a Total Maximum Daily Load (TMDL) for fecal coliforms in Bessey Creek (WBID 3211). Subsequent actions must be consistent with this TMDL. ____________ __/s/_____________________ ____2/5/2009____ James D. Giattina Date Director Water Protection Division

Fecal Coliform TMDL for Bessey Creek (WBDI 3211) January 2009

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TABLE OF CONTENTS ⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯

1. INTRODUCTION.............................................................................................................. 1

2. PROBLEM DEFINITION ................................................................................................ 4

3. WATERSHED DESCRIPTION....................................................................................... 4

4. WATER QUALITY STANDARD AND TARGET IDENTIFICATION..................... 8

5. WATER QUALITY ASSESSMENT ............................................................................... 8

6. SOURCE ASSESSMENT ............................................................................................... 12

6.1 Point Sources.................................................................................................................. 13 6.2 Nonpoint Sources ........................................................................................................... 13 6.3 Wildlife........................................................................................................................... 14 6.4 Agricultural Animals...................................................................................................... 14 6.5 Onsite Sewerage Treatment and Disposal Systems (Septic Tanks)............................... 14 6.6 Urban Development ....................................................................................................... 15

7. Analytical Approach........................................................................................................ 16

7.1 Percent Reduction Approach for TMDL Development ................................................. 16

8. Development of Total Maximum Daily Loads .............................................................. 17

8.1 Critical Conditions ......................................................................................................... 18 8.2 Margin of Safety............................................................................................................. 18 8.3 Determination of TMDL, LA and WLA........................................................................ 18 8.4 Waste Load Allocations ................................................................................................. 18 8.5 Load Allocations ............................................................................................................ 19 8.6 Seasonal Variation ......................................................................................................... 19 8.7 Recommendations .......................................................................................................... 19

9. REFERENCES................................................................................................................. 20

APPENDIX A: Water Quality Data...................................................................................... 21

APPENDIX B: Response to Public Comments .................................................................... 25


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LIST OF TABLES

⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯

Table 1: Land Cover Distribution for WBID 3211......................................................................... 6 Table 2: Monitoring Stations in Bessey Creek ............................................................................... 9 Table 3. Summary of Fecal Coliform Monitoring Data in WBID 3211........................................ 9 Table 4. Livestock Inventory by County (source: NASS, 2002)................................................ 14 Table 5. County Estimates of Septic Tank Installations (FDEP, 2004) ...................................... 15 Table 6. Summary of TMDL Components .................................................................................. 18 Table 7: Guide to Water Quality Remark Codes (Rcode column in data tables) ......................... 22 Table 8. Water Quality Data and Percentiles............................................................................... 22

LIST OF FIGURES

⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯

Figure 1: FDEP Group 2 River Basins ........................................................................................... 2 Figure 2: St. Lucie / Loxahatchee River Basin............................................................................... 3 Figure 3: South St. Lucie Planning Unit......................................................................................... 7 Figure 4. Sampling locations in Bessey Creek ........................................................................... 11 Figure 5. Comparison between Fecal Coliform concentrations in Bessey Creek and rainfall .... 12


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LIST OF ABBREVIATIONS ______________________________________________________________________________

AWT Advanced Waste Treatment BMP Best Management Practices BPJ Best Professional Judgment CFS Cubic Feet per Second DEM Digital Elevation Model DMR Discharge Monitoring Report EPA Environmental Protection Agency F.A.C. Florida Administrative Code GIS Geographic Information System HUC Hydrologic Unit Code LA Load Allocation MGD Million Gallons per Day MOS Margin of Safety MPN Most Probable Number MS4 Municipal Separate Storm Sewer Systems NASS National Agriculture Statistics Service NLCD National Land Cover Data NPDES National Pollutant Discharge Elimination System NRCS Natural Resources Conservation Service OSTD Onsite Sewer Treatment and Disposal Systems PLRG Pollutant Load Reduction Goal Rf3 Reach File 3 RM River Mile STORET STORage RETrieval database TMDL Total Maximum Daily Load USDA United States Department of Agriculture USGS United States Geological Survey WBID Water Body Identification WLA Waste Load Allocation WMP Water Management Plan WWTF Wastewater Treatment Facility

Fecal Coliform TMDL for Bessey Creek (WBID 3211) January 2009

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SUMMARY SHEET Total Maximum Daily Load (TMDL)

1. 303(d) Listed Waterbody Information State: Florida Major River Basin: St. Lucie

Impaired Waterbodies for TMDLs (1998 303(d) List):

WBID Segment Name and Type River Basin County Constituent(s)

3211 Bessey Creek Southeast Coast St. Lucie Fecal Coliform

2. TMDL Endpoints (i.e., Targets) for Class III Waters (fresh and marine): Fecal Coliform: Not to exceed 400 MPN/100ml in more than 10 percent of the samples and not to exceed 800 MPN/100ml in any one sample. Insufficient data were collected to evaluate the chronic fecal coliform criterion (i.e., 200 MPN/100ml expressed as geometric mean of 10 or more samples collected in a 30-day period).

3. Fecal Coliform Allocation:

WBID WLAwastewate

r (MPN/day)

WLAMS4

LA

TMDL

3211 7.95 x 108 92 percent reduction

92 percent reduction

92 percent reduction

Notes: 1) A 92 percent reduction is needed to meet both the 400 MPN/100ml and 800 MPN/100ml criteria (see Section 7.1); and 2) margin of safety is implicit. 4. Endangered Species (yes or blank): Yes 5. EPA Lead on TMDL (EPA or blank): EPA 6. TMDL Considers Point Source, Nonpoint Source, or both: Both 7. NPDES Discharges to surface waters addressed in TMDL:

Facility Name NPDES No. Facility Type Receiving Stream

Martin County Utilities (MCU) Consolidated Reuse System

FL0043214

Municipal Reuse System

Roebuck Creek and Bessey Creek

Martin County MS4 FLR04E013 MS4 Multiple

City of Stuart MS4 FLR04E031 MS4 Multiple

Sewall’s Point MS4 FLR04E044 MS4 Multiple Notes: 1) MCU is a minor facility with an NPDES permit requiring coliform limits in samples collected over a 30-day period to not exceed 25 fecal coliform values per 100 ml in any one sample and 75 percent of the values shall be below the detection limits; and 2) MS4 permittees will only be responsible for reducing the anthropogenic loads associated with stormwater outfalls they own or otherwise have responsible control over.


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TOTAL MAXIMUM DAILY LOAD (TMDL) FECAL COLIFORM IN BESSEY CREEK (WBID 3211)

1. INTRODUCTION

Section 303(d) of the Clean Water Act requires each state to list those waters within its boundaries for which technology based effluent limitations are not stringent enough to protect any water quality standard applicable to such waters. Listed waters are prioritized with respect to designated use classifications and the severity of pollution. In accordance with this prioritization, states are required to develop Total Maximum Daily Loads (TMDLs) for those water bodies that are not meeting water quality standards. The TMDL process establishes the allowable loadings of pollutants or other quantifiable parameters for a waterbody based on the relationship between pollution sources and in-stream water quality conditions, so that states can establish water quality based controls to reduce pollution from both point and non-point sources and restore and maintain the quality of their water resources (USEPA, 1991). The State of Florida Department of Environmental Protection (FDEP) developed a statewide, watershed-based approach to water resource management. Under the watershed management approach, water resources are managed on the basis of natural boundaries, such as river basins, rather than political boundaries. The watershed management approach is the framework DEP uses for implementing TMDLs. The state’s 52 basins are divided into 5 groups. Water quality is assessed in each group on a rotating five-year cycle. The Group 2 basin is shown in Figure 1 and includes the St. Lucie and Loxahatchee River Basins. The St. Lucie and Loxahatchee Basins encompass many square miles. To provide a smaller-scale geographic basis for assessing, reporting, and documenting water quality improvement projects, the FDEP subdivided the Group 2 area into smaller areas called planning units. Planning units help organize information and management strategies around prominent subbasin characteristics and drainage features. To the extent possible, planning units were chosen to reflect subbasins that had previously been defined by the South Florida Water Management District (SFWMD). The St. Lucie and Loxahatchee Basins contain eight planning units: C-25/Basin 1, North St. Lucie, C-24, C-23, South St. Lucie, C-44, Loxahatchee, and Coastal. Water quality assessments were conducted on individual waterbody segments within planning units. Each waterbody segment is assigned a unique waterbody identification (WBID) number. Waterbody segments are the assessment units or polygons that have historically been used by the FDEP to define waterbodies in their biannual inventory and reporting of water quality to EPA under Section 305(b) of the federal Clean Water Act. The same WBIDs are also the assessment units identified in the FDEP’s biannual lists of impaired waters submitted to EPA as part of their reporting under Section 303(d) of the Clean Water Act.


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Figure 1: FDEP Group 2 River Basins


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Figure 2: St. Lucie / Loxahatchee River Basin


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2. PROBLEM DEFINITION

Florida’s final 1998 Section 303(d) list identified WBID 3211 in the St. Lucie River Basin as not supporting water quality standards (WQS) due to fecal coliform bacteria. After assessing all readily available water quality data, EPA is responsible for developing a fecal coliform TMDL in WBID 3211, Bessey Creek. The location of WBID 3211 is shown in Figure 2. The TMDL addressed in this document is being established pursuant to EPA commitments in the 1998 Consent Decree in the Florida TMDL lawsuit (Florida Wildlife Federation, et al. v. Carol Browner, et al., Civil Action No. 4: 98CV356-WS, 1998). EPA first proposed a fecal coliform TMDL for Bessey Creek in September 2006. The TMDL analysis was based on five samples collected in 1992 and called for a 38 percent reduction in fecal coliform concentrations from existing condition. Subsequent to proposing the TMDL, FDEP collected water quality data over a two year period (2006-2007) at five locations in Bessey Creek to better characterize water quality conditions than what was done in the proposed TMDL. EPA reproposed the TMDL for Bessey Creek in December 2008 as the recent data indicated a greater reduction in fecal coliform is needed than what was originally proposed. After a public comment period, EPA is establishing the 2008 fecal coliform TMDL for Bessey Creek. WBID 3211 is designated as a Class III marine water. The designated use of Class III waters is recreation, propagation and maintenance of a healthy, well-balanced population of fish and wildlife. Class III waters are further categorized based on fresh or marine waters. Water quality criteria for fecal and total coliform do not vary between Class III fresh or marine waters.

3. WATERSHED DESCRIPTION

The following information is from the Basin Status Report for St. Lucie and Loxahatchee (FDEP, 2003). In the St. Lucie Basin, most of the land in the non-coastal areas is used for the production of citrus and beef cattle. The extensive network of canals that drains these agricultural areas transports storm-water runoff containing nutrients, sediment, bacteria, and other pollutants. These reach the natural drainage-ways (such as the North and South Forks of the St. Lucie River) and ultimately the St. Lucie Estuary and the South Indian River Lagoon. The St. Lucie Canal (C-44), the inland waterway that connects Lake Okeechobee to Florida’s east coast, transports regulated releases of water from Lake Okeechobee and runoff from agricultural areas within the C-44 basin. Other major canals also transport storm-water from inland agricultural areas to the estuary. Canals C-23 and C-24 discharge water into the North Fork of the St. Lucie River and the C-25 Canal discharges to the Indian River Lagoon. These canals transport loads of nutrients and eroded sediment to the estuary and slugs of fresh water that create fluctuations in estuarine salinity levels. Urban and residential areas continue to expand in the coastal areas, with polluted urban storm-water runoff and seepage from septic tanks also contributing to the water quality problems in streams and canals. As a result, parts of the St. Lucie Estuary (SLE) appear to be impaired by nutrients, copper, and low levels of DO. Nutrient


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loads, salinity fluctuations, and accumulations of sediment stress the estuarine ecology. Other evidence of impairment was gathered for the SLE segments in a FDEP South East District biological survey (Graves et al., June 2002). Sediment accumulation, decline of sea-grasses and oysters, algal blooms, fish kills, and low diversity of benthic macroinvertebrates in the SLE comprise this body of evidence. WBID 3211 is in the South St. Lucie planning unit of the St. Lucie Basin. The South St. Lucie planning unit lies in Martin County and includes most of the city of Stuart (in the southeastern part), plus portions of Palm City, Coral Gardens, Gomez, and Hobe Sound. This planning unit includes the natural drainage of the South St. Lucie River and includes several SFWMD subbasins. These include the Tidal St. Lucie subbasin which includes the South Fork of the SLE, Manatee Creek Basin, Bessey Creek drainage, and Danforth Creek. It also includes the eastern terminus of canal C-44 (St. Lucie Canal) through which flow is regulated by the S-80 structure. Bessey Creek (3211), is a tributary to the SLE. This segment of Bessey Creek exceeds the Planning List criteria for DO per the IWR and is also on the 1998 303(d) list for coliform, nutrients, Biochemical Oxygen Demand, and Dissolved Oxygen. Recent FDEP monitoring data not included in the preliminary assessment indicate that 3211 is also potentially impaired for nutrients based on chlorophyll-a detections. Another segment of Bessey Creek (3211A) does not have sufficient data to be assessed. There are four freshwater stream segments in the planning unit that were evaluated, South Fork of the St. Lucie River south of the estuary (3210B), Basin 6 (3215), Basin 5 (3217), and Basin 2 (3220). The South Fork segment is potentially impaired, exceeding the Verified List criteria for biology and for DO. It is also on the 1998 303(d) list for a variety of parameters including coliform, nutrients, BOD, and DO. Basins 6, 5, and 2 (3220) do not have sufficient data to be assessed. Wetlands comprise approximately 10 percent of this planning unit and upland forests cover approximately 25 percent of the area. The South Fork of the St. Lucie River and the Atlantic Ridge (in the southern part of this planning unit) are designated as a Save Our Rivers priority natural areas for acquisition. It is through the C-44 Canal discharge into the South Fork of the St. Lucie River that many of the ecological impacts to the SLE have been felt. The massive surges of fresh water have severely stressed the entire ecosystem of the estuary, dramatically reducing the salinity level at times. The sediment load carried by C-44 has blanketed the bottoms of the estuary, the river, and its tributaries and depleted the natural benthic habitat. Urban and agricultural canals that discharge to the estuary are in some respects equally to blame for the decline in the estuary (St. Lucie River Issues Team Report, 1998). Under the Feasibility Study, approximately 17,143 acres of pastureland in the Pal-Mar tract will be converted to a Natural Storage and Treatment Area. This area is in both the South St. Lucie (Tidal St. Lucie) and C-44 planning units. By plugging canals that would otherwise discharge directly to C-44 and the South Fork and by taking land out of agricultural land use, this component will improve water quality and reduce the sediment load to the river and estuary. Issues Team plans include three significant urban stormwater retrofit projects underway in the Stuart area. These include the Poppleton Creek, Fern Creek, and Frazier Creek projects that incorporate detention and treatment of urban stormwater before it reaches the St. Lucie River


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and the estuary. Approximately 25 percent of this planning unit is used for agricultural purposes, primarily in improved pastureland. Like elsewhere, implementation of best management practices (BMPs) to reduce polluted runoff from cow-calf operations are important to the improvement of water quality in the receiving waterbodies. WBID 3211 is highly developed with 51 percent residential and 18 percent commercial and industrial. The land cover distribution for these and other cover types is shown in Table 1 and is based on a 1999 coverage provided by the SFWMD. The WBID includes Bessey Creek and its tributaries from the Bessey Creek mouth at the St. Lucie River extending upstream about 5 kilometers. Table 1: Land Cover Distribution for WBID 3211

Land Cover Acreage Percentage Residential (1100-1390) 1823 51% Commercial, Industrial, Public (1400, 1500, 1800) 665 18% Agriculture (2000 series) 123 3% Rangeland (3000 series) 46 1% Forest (4000 series) 326 9% Water (5000 series) 247 7% Wetlands (6000 series) 286 8% Barren & Extractive (7000, 1600) 2 0% Transportation & Utilities (8000 series) 83 2% TOTAL (acres) 3599


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Figure 3: South St. Lucie Planning Unit


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4. WATER QUALITY STANDARD AND TARGET IDENTIFICATION

The water quality criteria for protection of Class III waters are established by the State of Florida in the Florida Administrative Code (F.A.C.), Section 62-302.530. The individual criteria should be considered in conjunction with other provisions in water quality standards, including Section 62-302.500 F.A.C. [Surface Waters: Minimum Criteria, General Criteria] that apply to all waters unless alternative or more stringent criteria are specified in F.A.C. Section 62-302.530. Fecal coliforms are a subset of the total coliform group and indicate the presence of fecal material from warm-blooded animals. Total coliform bacteria generally indicate the presence of soil-associated bacteria and result from natural influences on a water body such as rainfall runoff as well as sewage inflows. The most probable number (MPN) or membrane filter (MF) counts per 100 milliliter (ml) of fecal coliform bacteria shall not exceed a monthly average of 200, nor exceed 400 in 10 percent of the samples, nor exceed 800 on any one day. Monthly averages shall be expressed as geometric means based on a minimum of 10 samples taken over a 30-day period. The geometric mean criteria reflect chronic or long-term water quality conditions whereas the 400 and 800 values reflect acute or short-term conditions. The target for this TMDL is the daily 800 MPN/100 ml and the “not to exceed 400 in 10 percent of the samples” criteria, since insufficient monthly data were collected to evaluate the 200 MPN/100ml criterion. The TMDL evaluates the existing water quality data against both portions of the acute criterion. The criterion resulting in the largest percent reduction was selected for the TMDL. It is appropriate to use the more stringent of the acute criteria for fecal coliform TMDL development as the data indicates violations of the standard are typically related to storm events, which are short-term in nature. Violations of the chronic criteria are typically associated with point sources or non-point source continuous discharges (e.g., leaking septic systems) and typically occur during all weather conditions. Targeting the acute criterion should be protective of the chronic criterion.

5. WATER QUALITY ASSESSMENT

To determine the status of surface water quality in Florida, three categories of data, chemistry data, biological data, and fish consumption advisories, were evaluated to determine potential impairments. The level of impairment is defined in the Identification of Impaired Surface Waters Rule (IWR), Section 62-303 of the Florida Administrative Code (F.A.C.). The IWR defines FDEP’s threshold for identifying water quality limited WBIDs to be included on the State’s 303 (d) list. In addition, all waters on the 1998 303 (d) list that were not de-listed remain on the current 303 (d) list and require TMDLs. The WBID 3211 is on FDEP’s planning list for fecal coliform bacteria. EPA assessed data collected in this WBID and concluded that it is impaired, and a fecal coliform TMDL must be developed.


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FDEP maintains ambient monitoring stations throughout the basin and allows public access to the monitoring results via the internet in their IWR database. Data collected at monitoring stations within the impaired WBID and reported in IWR Run 32 were used in the analysis. Table 2 provides a list of these monitoring stations. Monitoring results are tabulated in Appendix A. Results having laboratory data qualifiers were used in the TMDL analysis in accordance with Appendix A. A summary of fecal coliform monitoring data collected at each station is provided in Table 3 and shows that 36 percent of all the observations exceed the 400 MPN/100 ml criterion and 29 percent of all the samples exceed the 800 MPN/100ml criterion. An insufficient number of samples were collected in a 30-day period to evaluate the geometric mean criterion. Most violations occur at stations 3211-A and 3211-C, located near urban areas (see Figure 4). Violations of the fecal coliform criteria often occur in response to rainfall events. Precipitation data collected at the St. Lucie County Airport (National Oceanic Atmospheric Administration Station 12895) located near WBID 3211 was plotted with the fecal coliform results to identify conditions when violations occurred (see Figure 5). In most instances, exceedances of the criteria occur in response to rain events while at other times exceedances occur during dry conditions. Implementation of this TMDL should address controlling nonpoint sources during both wet and dry weather conditions. Table 2: Monitoring Stations in Bessey Creek

Station ID Station Name Number of Observations

Start Date

End Date

21FLBRA 3211-A Bessey Creek - covered bridge 7 5/16/2006 10/19/2006

21FLBRA 3211-B Bessey Creek bridge off Murphy Rd 6 5/16/2006 10/10/2006

21FLBRA 3211-C Bessey Creek - End of Mapp Rd 7 5/16/2006 10/19/200621FLWPB8010047 BESSEY CRK AT MURPHY RD 13 3/14/2006 11/20/2007

21FLWPB 8010176 MOUTH OF BESSEY CR PRIOR JCT WITH C23 12 3/14/2006 11/20/2007

Table 3. Summary of Fecal Coliform Monitoring Data in WBID 3211

Station ID % Samples > 400 (MPN/100ml)

% Samples > 800 (MPN/100ml)

Minimum Concentration (MPN/100ml)

Maximum Concentration (MPN/100ml)

21FLBRA 3211-A 43% 43% 21 2600 21FLBRA 3211-B 33% 33% 42 9200 21FLBRA 3211-C 100% 100% 1010 1230 21FLWPB 28010047 23% 8% 1 2400 21FLWPB 28010176 8% 0% 30 450


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All Data 36% 29% 1 9200


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Figure 4. Sampling locations in Bessey Creek


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Fecal Coliform in WBID 3211

1

10

100

1000

10000

100000

1/1/2006

3/2/2006

5/1/2006

6/30/2006

8/29/2006

10/28/200

6

12/27/200

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2/25/2007

4/26/2007

6/25/2007

8/24/2007

10/23/200

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Sta 3211-A Sta 3211-B Sta 3211-C Sta 28010047 Sta 28010176 Rainfall

Figure 5. Comparison between Fecal Coliform concentrations in Bessey Creek and rainfall

6. SOURCE ASSESSMENT

An important part of the TMDL analysis is the identification of source categories, source subcategories, or individual sources of coliform bacteria in the watershed and the amount of pollutant loading contributed by each of these sources. Sources are broadly classified as either point or non-point sources. A point source is defined as a discernable, confined, and discrete conveyance from which pollutants are or may be discharged to surface waters. Point source discharges of industrial wastewater and treated sanitary wastewater must be authorized by National Pollutant Discharge Elimination System (NPDES) permits. NPDES permitted facilities discharging treated sanitary wastewater or stormwater (i.e., Phase I or II MS4 discharges) are considered primary point sources of coliform. Non-point sources of coliform are diffuse sources that cannot be identified as entering a waterbody through a discrete conveyance at a single location. These sources generally, but not always, involve accumulation of bacteria on land surfaces and wash off as a result of storm events. Typical non-point sources of coliform include:

• Wildlife • Agricultural animals • Onsite Sewer Treatment and Disposal Systems (septic tanks)


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• Urban development (outside of Phase I or II MS4 discharges) A geographic information system (GIS) tool was used to display, analyze, and compile available information to characterize potential bacteria sources in the impaired WBID. This information includes land use, point source dischargers, soil types and characteristics, population data (human and livestock), and stream characteristics.

6.1 Point Sources Figure 3 shows permitted wastewater treatment facilities, landfills, and delineated areas in the South St. Lucie River planning unit. The Martin County Utilities (MCU) Consolidated Reuse System (FL0043214) is a minor wastewater reclamation/reuse facility with an existing 0.84 MGD three month average daily flow permitted capacity. This reuse facility receives treated effluent from three wastewater treatment facilities (WWTF) and after receiving high level disinfection, the effluent from the reuse facility discharges into a common distribution main where it is distributed to golf course ponds and land application sites. When effluent from the WWTF does not meet high level disinfection standards the effluent is not permitted to be diverted to the land application sites, but rather deep injection wells are used as a back-up disposal option. Golf course ponds are built primary to contain stormwater, but reclaimed water can be pumped into them if excess capacity is available in the ponds. The MCU permit allows intermittent discharges from these ponds during periods of heavy rainfall. The existing permit requires monitoring and reporting of effluent samples collected at the outlets of these golf course ponds to demonstrate “no net increase” in nutrients to the down stream waters. Monitoring and reporting of fecal coliform is required in the permit to ensure that the reclaimed water meets the following limits: over a 30-day period, 75 percent of the fecal coliform values are below the detection limit and any one sample does not exceed 25 fecal coliform values per 100 ml. The reclaimed water limits for fecal coliform values is well below the water quality criteria and therefore, discharge from the reuse facility should not cause or contribute to water quality violations in Bessey Creek. Municipal Separate Storm Sewer Systems (MS4s) may also discharge bacteria to waterbodies in response to storm events. Large, medium, and small MS4s serving populations greater than 50,000 people, or with an overall population density of 1,000 people per square mile, are required to obtain a NPDES storm water permit. There are three MS4 permits in Martin County; Martin County (FLR04E013), City of Stuart (FLR04E031), and Sewall’s Point (FLR04E044).

6.2 Nonpoint Sources Runoff from urban and agricultural areas impacts water quality in Bessey Creek and its tributaries. Predominant land uses in the South St. Lucie planning unit are agriculture (34 percent) and urban/built-up (26 percent). The primary agricultural land use is improved pasture (25 percent of planning unit). The predominant land use within the urban/built-up category is low-density residential (approximately 10 percent).


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6.3 Wildlife Wildlife deposit bacteria in their feces onto land surfaces where it can be transported during storm events to nearby streams. Bacteria load from wildlife is assumed background, since the contribution from this source is small relative to the load from urban and agricultural areas. Water fowl (e.g., egrets, ducks, wood storks, herons) often frequent storm-water ponds. Depending on the number of birds, the contributions of fecal coliform could result in stream concentrations above the criteria.

6.4 Agricultural Animals Agricultural animals are the source of several types of coliform loadings to streams, that impact water quality. This source includes agriculture runoff from pastureland and cattle in streams. The land use within the impaired WBID is only 4 percent agricultural and rangeland (Table 1), so this landuse likely does not discharge a significant amount of the bacteria load. The USDA National Agricultural Statistics Service (NASS) compiles Census of Agriculture data by county for virtually every facet of U.S. agriculture (USDA, 2002). The “Census of Agriculture Act of 1997” (Title 7, United States Code, Section 2204g) directs the Secretary of Agriculture to conduct a census of agriculture on a 5-year cycle collecting data for the years ending in 2 and 7. Livestock inventory from the 2002 Census of Agriculture reports for Martin County is listed in Table 4. Cattle and calves are the predominate livestock. Confined Animal Feeding Operations (CAFOs) are not known to operate in either St. Lucie or Martin County. In 2002, NASS reported 221,537 acres of farmland in St. Lucie County and 206,198 acres of farmland in Martin County.

Table 4. Livestock Inventory by County (source: NASS, 2002)

Livestock (inventory) Martin County

Cattle and calves 27,279 Hogs and Pigs 439

6.5 Onsite Sewerage Treatment and Disposal Systems (Septic Tanks) Onsite sewage treatment and disposal systems (OSTDs) including septic tanks are commonly used where providing central sewer is not cost effective or practical. When properly sited, designed, constructed, maintained, and operated, OSTDs are a safe means of disposing of domestic waste. The effluent from a well-functioning OSTD is comparable to secondarily treated wastewater from a sewage treatment plant. When not functioning properly, OSTDs can be a source of nutrient (nitrogen and phosphorus), pathogens, and other pollutants to both ground


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water and surface water. The State of Florida Department of Health publishes septic tanks data on a county basis (www.doh.state.fl.us/environment/ostds/statistics/ostdsstatistics.htm). Table 5 summarizes the cumulative number of septic systems installed since the 1970 census. The data does not reflect septic tanks removed from service.

Table 5. County Estimates of Septic Tank Installations

County Number Septic Tanks

(1970- 2002)

Martin 27,284

6.6 Urban Development Fecal coliform loading from urban areas is attributable to multiple sources including storm-water runoff, leaks and overflows from sanitary sewer systems, illicit discharges of sanitary waste, runoff from improper disposal of waste materials, leaking septic systems, and domestic animals. Urban land uses include residential, industrial, extractive and commercial categories. Fecal coliform loading from urban areas (whether within an MS4 jurisdiction or not) is attributable to multiple sources including storm water runoff, leaks and overflows from sanitary sewer systems, illicit discharges of sanitary waste, runoff from improper disposal of waste materials, leaking septic systems, and domestic animals. In 1982, Florida became the first state in the country to implement statewide regulations to address the issue of nonpoint source pollution by requiring new development and redevelopment to treat stormwater before it is discharged. The Stormwater Rule, as outlined in Chapter 403 of the Florida Statutes was established as a technology-based program that relies upon the implementation of BMPs that are designed to achieve a specific level of treatment (i.e., performance standards). Florida’s stormwater program is unique in having a performance standard for older stormwater systems that were built before the implementation of the Stormwater Rule in 1982. This rule states: “the pollutant loading from older stormwater management systems shall be reduced as needed to restore or maintain the beneficial uses of water” (Section 62-40-.432 (5) (c), F.A.C.). In 1994, state legislation created the Environmental Resource Permitting program to consolidate stormwater quantity, stormwater quality, and wetlands protection into a single permit. Presently, the majority of environmental resource permits are issued by the state’s water management districts, although DEP continues to issue permits for specific projects. Nonstructural and structural BMPs are an integral part of Florida’s stormwater programs. Nonstructural BMPs, often referred to as “source controls”, are those that can be used to prevent the generation of NPS pollutants or to limit their transport off-site. Typical nonstructural BMPs include public education, land use management, preservation of wetlands and floodplains, and


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minimizing impervious surfaces. Technology-based structural BMPs are used to mitigate the increased stormwater peak discharge rate, volume, and pollutant loadings that accompany urbanization.

7. Analytical Approach

The approach for calculating coliform TMDLs depends on the number of water quality samples and the availability of flow data. When long-term records of water quality and flow data are not available, the TMDL is expressed as a percent reduction. Load duration curves are used to develop TMDLs when significant data are available to develop a relationship between flow and concentration. Flow measurements are not available for WBID 3211, nor were sufficient information available to estimate flow; therefore, these TMDLs are expressed as a percent reduction.

7.1 Percent Reduction Approach for TMDL Development The percent reduction needed to meet the applicable criterion is calculated based on a percentile of all measured concentrations. The (p X 100) percentile is the value with the cumulative probability of p. For example, the 90th percentile has a cumulative probability of 0.90. The 90th percentile is also called the 10 percent exceedance event because it will be exceeded with the probability of 0.10. Therefore, considering a set of water quality data, 90 percent of the measured values are lower than the 90th percentile concentration and 10 percent are higher. Since the water quality standard states the fecal coliform concentration shall not exceed 400 in 10 percent of the samples, 400 should be targeted with a percentile slightly larger than 90 to ensure less than 10 percent of the values exceed 400. A 95th percentile of 400 counts per 100 ml was initially selected as the target for this TMDL. This would meet the water quality standard and provide a margin of safety by ensuring that only 5 percent of the data exceed a concentration of 400. There are many formulas for calculating percentiles and these can be found in text books on statistics. The Hazen formula was used to calculate the 95th percentile, as it is recommended in Hunter’s Applied Microbiology (2002) article on bacteria in water. Application of the Hazen formula to data collected in WBID 3211 is provided in Appendix A. The percent reduction was also calculated using the maximum concentration measured in the WBID and the 800 MPN/100ml criterion. The larger of the two percent reduction values was selected as the TMDL. The TMDL percent reduction required to meet the coliform criteria is based on the following equation: Percent Reduction = (maximum measured concentration – 400) / maximum measured concentration × 100 (Equation 1) In WBID 3211, the maximum concentration is 9200 MPN/100ml, and a 92 percent reduction is necessary to meet the not to exceed 800 MPN/100ml in any one sample criterion. The 95th percentile concentration of the available fecal coliform data is 5,050 MPN/100ml, and a 92


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percent reduction is necessary to meet the not to exceed 400 MPN/100ml criterion. Therefore, a 92 percent reduction is necessary to meet both portions of the water quality standard.

8. Development of Total Maximum Daily Loads

The TMDL process quantifies the amount of a pollutant that can be assimilated in a waterbody, identifies the sources of the pollutant, and recommends regulatory or other actions to be taken to achieve compliance with applicable water quality standards based on the relationship between pollution sources and in-stream water quality conditions. A TMDL can be expressed as the sum of all point source loads (Waste Load Allocations (WLA)), non-point source loads (Load Allocations (LA)), and an appropriate margin of safety (MOS), which takes into account any uncertainty concerning the relationship between effluent limitations and water quality:

TMDL = Σ WLAs + Σ LAs + MOS

As discussed earlier, the WLA is broken out into separate subcategories for wastewater discharges and stormwater discharges regulated under the NPDES Program:

TMDL ≅ ∑ WLAswastewater + ∑ WLAsNPDES Stormwater + ∑ LAs + MOS

The various components of the TMDL equation may not sum up to the value of the TMDL because: a) the WLA for NPDES stormwater is typically based on the percent reduction needed for nonpoint sources and is also accounted for within the LA; and b) TMDL components can be expressed in different terms (e.g.,, the WLA for stormwater is typically expressed as a percent reduction, and the WLA for wastewater is typically expressed as mass per day). WLAs for stormwater discharges are typically expressed as “percent reduction” because it is very difficult to quantify the loads from MS4s (given the numerous discharge points) and to distinguish loads from MS4s from other nonpoint sources (given the nature of stormwater transport). The permitting of stormwater discharges also differs from the permitting of most wastewater point sources. Because stormwater discharges cannot be centrally collected, monitored, and treated, they are not subject to the same types of effluent limitations as wastewater facilities, and instead are required to meet a performance standard of providing treatment to the “maximum extent practical” through the implementation of BMPs. This approach is consistent with federal regulations (40 CFR § 130.2(i)), which state that TMDLs can be expressed in terms of mass per time (e.g., pounds per day), toxicity, or other appropriate measure. The TMDL for Bessey Creek is expressed as a percent reduction. The TMDL is expressed as a daily load by multiplying the water quality target by an estimate of flow in the WBID. Bessey Creek is an ungaged waterbody and therefore it is not possible to estimate flow with the available data. However, it is recommended that flow be measured at the time of sampling to ensure compliance with the TMDL. The maximum one day load the creek can transport in any 30-day period and maintain water quality standards is calculated by


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multiplying 800 MPN/100 ml times the flow (in cubic feet per second) and a conversion factor to obtain units of fecal coliform counts/day.

8.1 Critical Conditions The critical condition for non-point source coliform loading is an extended dry period followed by a rainfall runoff event. During the dry weather period, coliforms build up on the land surface, and are washed off by rainfall. The critical condition for point source loading occurs during periods of low stream flow when dilution is minimized. Water quality data have been collected during both time periods. Most violations occur in response to rain events. Critical conditions are accounted for in the analyses by using the entire period of record of measured water quality data available for the WBID.

8.2 Margin of Safety TMDLs shall include a margin of safety (MOS) that takes into account any lack of knowledge about the pollutant loading and in-stream water quality. In this case the lack of knowledge concerns the data, and how well it represents the true water quality. There are two methods for incorporating a MOS in the analysis: 1) implicitly incorporate the MOS using conservative assumptions to develop allocations; or 2) explicitly specify a portion of the TMDL as the MOS and use the remainder for allocations. In the Bessey Creek TMDL, an implicit MOS was used by targeting reductions that will result in no more than 5 percent of the samples exceeding a concentration of 400 MPN/100ml even though the standard requires less than 10 percent exceedance. In addition, the TMDL requires very high reductions from nonpoint sources.

8.3 Determination of TMDL, LA and WLA The TMDL values represent the maximum daily load the stream can assimilate and maintain water quality standards. The TMDL is based on the percent reduction needed to meet the daily 800 MPN/100ml and the “not to exceed 400 MPN/100ml in 10 percent of the samples” Class III WQS. A 92 percent reduction is required to meet both portions of the acute criteria. TMDL components for Bessey Creek are summarized in Table 6.

Table 6. Summary of TMDL Components

WLA

Stream Name / WBID Parameter WWTF

(MPN/day) MS4

LA

TMDL

Bessey Creek (3211)

Fecal Coliform 7.95 x 108 92%

reduction 92%

reduction 92%

reduction

8.4 Waste Load Allocations


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The Martin County Utilities (MCU) Consolidated Reuse System (FL0043214) is given a WLA based on the existing permitted flow (0.84 mgd) and the one-day maximum single sample concentration of 25 MPN/100ml. The permit requires that 75 percent of the time the effluent concentration is below detection limits. The WLA is calculated as follows: WLA = 0.84 mgd * 25 MPN/100ml * 3.785 l/gal * 106 * 1000 ml/l = 7.95 x 108 MPN/day The waste load allocation for MS4s impacting Bessey Creek is a 92 percent reduction from existing concentrations. MS4 permittees will only be responsible for reducing the anthropogenic loads associated with stormwater outfalls they own or otherwise has responsible control over.

8.5 Load Allocations There are two modes of transport for non-point source coliform bacteria loading into the stream. First, fecal coliform loading from failing septic systems and animals in the stream are considered direct sources of coliform to the stream, since they are independent of precipitation. The second mode involves coliform loadings resulting from accumulation on land surfaces transported to streams during storm events. Thus, according to this data, the load allocation of 92 percent reduction should target both direct sources (i.e., failing septic tanks) and rain events since the violations occur during both wet and dry periods.

8.6 Seasonal Variation Seasonality was addressed by using all water quality data associated with the impaired WBID, which was collected during multiple seasons over several years.

8.7 Recommendations It is recommended that flow be measured at the time of sampling so that loads can be calculated. Determining the source of bacteria in waterbodies is the initial step to implementing a coliform TMDL. FDEP employs the Basin Management Action Plan (B-MAP) as the mechanism for developing strategies to accomplish the necessary load reductions. Components of a B-MAP are:

• Allocations among stakeholders • Listing of specific activities to achieve reductions • Project initiation and completion timeliness • Identification of funding opportunities • Agreements • Local ordinances • Local water quality standards and permits • Follow-up monitoring


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9. REFERENCES

Cleland, Bruce, 2003. TMDL development from the “bottom up” – Part III: Duration curves and wet-weather assessments. America’s Clean Water Foundation, Washington, DC. September 15, 2003. Florida Administrative Code (F.A.C.). Chapter 62-302, Surface Water Quality Standards. Florida Department of Environmental Protection (FDEP), 2003. Basin Status Report, St. Lucie and Loxahatchee Basin, FDEP Division of Water Resource Management, Group 2 Basin, February 2003. Graves, Gregory A., Wan, Yongshan and Fike, Dana L., 2004. Water Quality Characteristics of Storm Water From Major Land Uses in South Florida, Journal of the American Water Resources Association, December 2004, 40(6):1405-1419. Hunter, P.R. 2002. The Society for Applied Microbiology, Letters in Applied Microbiology. 34. 283–286. USDA, 2002. 2002 Census of Agriculture, Volume 1, Geographic Area Series, Part 9, U.S. Department of Agriculture, National Agricultural Statistics Service. AC02-A-9, June 2004. USDA, 1997. 1997 Census of Agriculture, Volume 1, Geographic Area Series, Part 42, U.S. Department of Agriculture, National Agricultural Statistics Service. AC97-A-42, March 1999. USEPA, 1991. Guidance for Water Quality –based Decisions: The TMDL Process. U.S. Environmental Protection Agency, Office of Water, Washington, DC. EPA-440/4-91-001, April 1991.


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APPENDIX A: Water Quality Data


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Table 7: Guide to Water Quality Remark Codes (Rcode column in data tables)

Remark Code

Definition Use in TMDL

A Value reported is mean of two or more samples

Data included in analysis as reported

B Result based on colony counts outside the acceptable range


E Extra sample taken in compositing process Data included as average I The value reported is less than the practical

quantification limit and greater than or equal to the method detection limit.


J Estimated. Value shown is not a result of analytical measurement.


K Off-scale low. Actual value not known, but known to be less than value shown


L Off-scale high. Actual value not known, but known to be greater than value shown


Q Sample held beyond normal holding time Data used in analysis – holding samples on ice slows the metabolism of the organisms resulting in no appreciable growth. Actual concentration is expected to be at least as high as the value reported.

T Value reported is less than the criteria of detection

Data included in analysis if the reported value is below criteria; otherwise, reported value is not used in the analysis

U Material was analyzed for but not detected. Value stored is the limit of detection.

Data not included in analysis

< NAWQA – actual value is known to be less than the value shown

Data included in analysis

Z Too many colonies were present to count (TNTC), the numeric value represents the filtration volume

Data not included in analysis

Table 8. Water Quality Data and Percentiles

Date Station Result Rcode Rank

Percentile by

Hazen method

4/18/2007 21FLWPB 28010047 1 1 1% 8/4/2006 21FLBRA 3211-A 21 2 3%


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Percentile by

Hazen method

10/31/2006 21FLWPB 28010047 28 B 3 6% 6/21/2006 21FLWPB 28010176 30 B 4 8% 2/20/2007 21FLWPB 28010047 39 5 10% 5/22/2006 21FLWPB 28010047 40 B 6 12% 10/9/2007 21FLWPB 28010176 40 B 7 14% 7/20/2006 21FLBRA 3211-B 42 8 17% 2/23/2007 21FLWPB 28010176 42 9 19% 4/18/2007 21FLWPB 28010176 47 10 21% 3/14/2006 21FLWPB 28010176 48 B 11 23% 9/8/2006 21FLBRA 3211-C 50 12 26%

10/31/2006 21FLWPB 28010176 69 B 13 28% 5/22/2006 21FLWPB 28010176 70 B 14 30% 4/21/2007 21FLWPB 28010047 72 B 15 32% 8/7/2007 21FLWPB 28010047 84 16 34% 8/4/2006 21FLBRA 3211-C 88 17 37% 8/7/2007 21FLWPB 28010176 92 18 39%

11/20/2007 21FLWPB 28010047 94 19 41% 9/13/2006 21FLWPB 28010047 96 20 43% 7/20/2006 21FLBRA 3211-A 110 21 46% 4/12/2006 21FLWPB 28010176 110 B 22 48%

11/20/2007 21FLWPB 28010176 144 B 23 50% 9/8/2006 21FLBRA 3211-A 145 24 52%

7/20/2006 21FLBRA 3211-C 160 25 54% 8/4/2006 21FLBRA 3211-B 190 26 57%

10/10/2006 21FLBRA 3211-A 200 27 59% 9/8/2006 21FLBRA 3211-B 230 28 61%

6/21/2006 21FLWPB 28010047 230 29 63% 10/9/2007 21FLWPB 28010047 275 30 66%

10/10/2006 21FLBRA 3211-B 330 31 68% 9/5/2006 21FLWPB 28010176 390 32 70%

4/12/2006 21FLWPB 28010047 410 33 72% 9/5/2006 21FLWPB 28010047 430 34 74%

9/13/2006 21FLWPB 28010176 450 35 77% 6/14/2006 21FLBRA 3211-B 1100 36 79% 6/14/2006 21FLBRA 3211-A 1300 37 81% 5/16/2006 21FLBRA 3211-A 1700 38 83%

10/19/2006 21FLBRA 3211-C 2400 39 86% 3/14/2006 21FLWPB 28010047 2400 40 88%


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Percentile by

Hazen method

10/19/2006 21FLBRA 3211-A 2600 41 90% 5/16/2006 21FLBRA 3211-C 4600 42 92% 6/14/2006 21FLBRA 3211-C 4900 43 94% 10/10/2006 21FLBRA 3211-C 5500 44 97% 5/16/2006 21FLBRA 3211-B 9200 45 99%

In this TMDL the Hazen formula was used since it is recommended in Hunter’s Applied Microbiology (2002) article concerning bacteria in water. To calculate the percentile associated with the sample concentrations the data are first sorted by concentration, lowest to highest. A ranking is assigned to each sample, with the lowest concentration having a rank of 1 and the highest concentration having a rank equivalent to the total number of samples collected. The percentile is calculated as follows:

Percentile = (Rank – 0.5)/ (total number of samples collected) For example, on June 14, 2006 a fecal coliform concentration of 1300 MPN/100ml was measured at station 3211-A. This concentration ranks number 37 out of 45 samples collected in Bessey Creek. The associated percentile is calculated as:

Percentile = (37-0.5)/45 = 0.811 = 81% This implies that 81 percent of the time the instream concentration is less than 1300 MPN/100ml.


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APPENDIX B: Response to Public Comments The South Florida Water Management District was the only public entity to submit comments on the fecal coliform TMDL EPA proposed in September 2006 for Bessey Creek. The comments pertain to several TMDLs EPA proposed in the South Florida, including Bessey Creek (WBID 3211), C-25 Canal West (WBID 3160 and 3189), and North Fork St. Lucie River (WBID 3194). The TMDL for Bessey Creek has been modified based on some of these comments, as indicated below. Comment:

Response: TMDLs prescribe reductions necessary to achieve the water quality standard (WQS). The WQS for bacteria in expressed in terms of most probable number (MPN) of Fecal Coliform per 100 ml of sample. Although E. coli may be a better indicator for predicting human health impacts, the State of Florida has not adopted this parameter into their WQS for freshwater streams. Until that occurs, TMDLs for bacteria target achieving the WQS for fecal coliform. EPA and FDEP are developing TMDLs in accordance to a Consent Decree schedule that is independent of the amount of data available. FDEP will be able to reopen the TMDLs as data become available in the future and propose new ones should the data indicate a significant change from the original analysis. The TMDLs have been updated to include recent data (2006-2007) and if the reductions change significantly, as they have with the Bessey Creek fecal coliform TMDL, EPA will repropose the TMDL before finalizing it. Comment:

Response:


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The watershed descriptions are summarized from the Basin Status Reports published by FDEP. The level of detail provided in the TMDL document is dependent on the amount of data readily available to EPA. In some instances, EPA was able to obtain Geographic Information System (GIS) spatial coverages of landuse data from which EPA could categorize landuse practices to the watershed scale. It was not possible to calculate the bacteria loadings from each individual landuse practice as sufficient data were not available to quantify site-specific runoff coefficients or concentrations. Rather, EPA provided a single allocation for point sources and one allocation for nonpoint sources. Comment:


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Response: Bacteria Source Tracking information was not available for use in developing any of the TMDLs addressed in this summary. EPA encourages the collection of this type of information and that it be considered during the implementation of the TMDL. During implementation additional site-specific information should be collected to better characterize failing septic systems, illicit discharges, and other secondary sources of fecal coliform bacteria. Comment:

Response: The TMDLs are expressed as percent reductions as flow data were not available to estimate allowable bacteria loads. Furthermore, fecal coliform TMDLs expressed as loads are not measurable as the typical values are on the order of 1013 counts/day. TMDLs for fecal coliform are more meaning when expressed as percent reduction and concentration, as this will guide implementation as to the level of Best Management Practices (BMPs) needed to achieve WQS. It is unfortunate that there are a limited number of samples collected in the impaired WBIDs, but because of Consent Decree requirements, EPA is required to finalize TMDLs within a reasonable time period. As additional water quality data become available, FDEP will be able to reassess the waterbody and reopen the TMDLs as necessary. EPA considers the reductions provided in the TMDL documents to be conservative and necessary to achieve all three components of the WQS for fecal coliform. Comment:


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Response: It was not possible to allocate specific loads to each nonpoint source category in the impaired WBIDs because of the limited data available. EPA was able to evaluate the individual point sources in the watershed, but only those point sources discharging directly to surface waters were given a waste load allocation. Comment:

Response: Critical conditions and seasonal variations are considered in the TMDL analysis as all data are used to develop the allocations. Fecal coliform data are collected during all times of the year and by using all the data seasonal variation is considered in the analysis, as compared to basing the allocations on data collected in one season. In the absence of flow data, the TMDLs considered critical conditions by evaluating the water quality data using rainfall data. In general, most violations of the water quality standard occurred after rainfall events; therefore, controlling wet weather sources are the critical conditions when the waterbody is most vulnerable to standards violations. Comment:


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Response: Water quality data collected in the impaired WBIDs was correlated to rainfall data to demonstrate whether the violation occurred during high or low flow periods. In most of the waterbodies data are collected predominately at one station, although there are instances when limited data are collected at other locations in the WBIDs; however, the amount of data collected at these other stations is too limited to draw conclusions regarding sources and stream flow conditions under which the sample was taken. The final TMDL documents include the data used in the analyses and any data qualifiers. The data are plotted by station to show the spatial distribution along the stream segment. Water quality data that had data qualifiers indicating laboratory remarks about a particular sample were evaluated individually to determine whether the sample should be included or not. The particular sample referred to in the comment was collected in the North Fork St. Lucie River (WBID 3194) and most likely represents an outlier as no other sample collected in subsequent years was this high. The TMDL for WBID 3194 was recalculated using recent data and older data without qualifiers.

References South Florida Water Management District (SFWMD), 2007. Letter to Ms. Sibyl Cole, USEPA Region 4, from Mr. Kirk L. Burns, SFWMD, regarding Fecal Coliform TMDLs for select basins and segments of the Southern Indian River Lagoon and St. Lucie Estuary, February 13, 2007.

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