FINAL TMDL Report
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FLORIDA DEPARTMENT OF ENVIRONMENTAL PROTECTION Division of Environmental Assessment and Restoration, Bureau of Watershed Restoration NORTHWEST DISTRICT • PERDIDO RIVER AND BAY BASIN FINAL TMDL Report Fecal Coliform TMDL for Brushy Creek (WBID 4) Kyeongsik Rhew, Ph.D. August 2012 FINAL TMDL Report: Perdido River and Bay Basin, Brushy Creek (WBID 4), Fecal Coliform, August 2012 Acknowledgments This Total Maximum Daily Load (TMDL) analysis could not have been accomplished without significant contributions from staff in the Florida Department of Environmental Protection’s (Department) Northwest District Office, Watershed Assessment Section, and Watershed Evaluation and TMDL Section. Map production assistance was provided by the Watershed Data Services Section within the Department’s Division of Environmental Assessment and Restoration. Editorial assistance was provided by Jan Mandrup-Poulsen and Linda Lord. For additional information on the watershed management approach and impaired waters in the Perdido Bay Basin, contact: Charles Gauthier Florida Department of Environmental Protection Bureau of Watershed Restoration Watershed Planning and Coordination Section 2600 Blair Stone Road, Mail Station 3565 Tallahassee, FL 32399-2400 Email: [email protected] Phone: (850) 245–8555 Fax: (850) 245–8434 Access to all data used in the development of this report can be obtained by contacting: Kyeongsik Rhew Florida Department of Environmental Protection Bureau of Watershed Restoration Watershed Evaluation and TMDL Section 2600 Blair Stone Road, Mail Station 3555 Tallahassee, FL 32399-2400 Email: [email protected] Phone: (850) 245–8461 Fax: (850) 245–8444 ii Florida Department of Environmental Protection FINAL TMDL Report: Perdido River and Bay Basin, Brushy Creek (WBID 4), Fecal Coliform, August 2012 Contents Chapter 1: INTRODUCTION ___________________________________ 1 1.1 Purpose of Report _____________________________________________ 1 1.2 Identification of Waterbody ______________________________________ 1 1.3 Background ___________________________________________________ 1 Chapter 2: DESCRIPTION OF WATER QUALITY PROBLEM ________ 4 2.1 Statutory Requirements and Rulemaking History ____________________ 4 2.2 Information on Verified Impairment _______________________________ 4 2.3 Period of Record Trend _________________________________________ 5 Chapter 3. DESCRIPTION OF APPLICABLE WATER QUALITY STANDARDS AND TARGETS __________________________________ 7 3.1 Classification of the Waterbody and Criterion Applicable to the TMDL ________________________________________________________ 7 3.2 Applicable Water Quality Standards and Numeric Water Quality Target ________________________________________________________ 7 Chapter 4: ASSESSMENT OF SOURCES ________________________ 8 4.1 Types of Sources ______________________________________________ 8 4.2 Potential Sources of Fecal Coliform within the Brushy Creek WBID Boundary _____________________________________________________ 8 4.2.1 Point Sources ___________________________________________ 8 Wastewater Point Sources ____________________________________________ 8 Municipal Separate Storm Sewer System Permittees ______________________ 8 4.2.2 Land Uses and Nonpoint Sources ___________________________ 8 Land Uses __________________________________________________________ 9 Wildlife and Sediments _______________________________________________ 9 Chapter 5: DETERMINATION OF ASSIMILATIVE CAPACITY _______ 12 5.1 Determination of Loading Capacity ______________________________ 12 5.1.1 Data Used in the Determination of the TMDL _________________ 12 Temporal Patterns __________________________________________________ 14 Spatial Patterns ____________________________________________________ 17 5.1.2 Critical Condition ________________________________________ 19 5.1.3 TMDL Development Process ______________________________ 22 Chapter 6: DETERMINATION OF THE TMDL ____________________ 26 6.1 Expression and Allocation of the TMDL ___________________________ 26 6.2 Load Allocation _______________________________________________ 27 6.3 Wasteload Allocation __________________________________________ 27 iii Florida Department of Environmental Protection FINAL TMDL Report: Perdido River and Bay Basin, Brushy Creek (WBID 4), Fecal Coliform, August 2012 6.3.1 NPDES Wastewater Discharges ____________________________ 27 6.3.2 NPDES Stormwater Discharges ____________________________ 27 6.4 Margin of Safety ______________________________________________ 27 Chapter 7: TMDL IMPLEMENTATION __________________________ 28 7.1 Basin Management Action Plan _________________________________ 28 7.2 Other TMDL Implementation Tools _______________________________ 29 References ________________________________________________ 30 Appendices _______________________________________________ 32 Appendix A: Background Information on Federal and State Stormwater Programs _________________________________________ 32 Appendix B: Estimates of Fecal Coliform Loadings from Potential Sources _____________________________________________________ 33 Agriculture __________________________________________________ 33 Pets ________________________________________________________ 33 Septic Tanks ________________________________________________ 34 Wildlife _____________________________________________________ 38 List of Tables Table 2.1. Summary of Fecal Coliform Monitoring Data for Brushy Creek During the Cycle 1 Verified Period (January 1, 1999– June 30, 2006) and Cycle 2 Verified Period (January 1, 2004– June 30, 2011) ____________________________________________ 5 Table 2.2. Summary of Fecal Coliform Monitoring Data for Brushy Creek During the Cycle 2 Verified Period (January 1, 2004– June 30, 2011) ____________________________________________ 5 Table 4.1. Classification of Land Use Categories within the Brushy Creek WBID Boundary ____________________________________ 10 Table 5.1a. Summary Statistics of Fecal Coliform Data for All Stations in Brushy Creek by Month During the Cycle 2 Verified Period (January 1, 2004–June 30, 2011) ____________________________ 15 Table 5.1b. Summary Statistics of Fecal Coliform Data for All Stations in Brushy Creek by Season During the Cycle 2 Verified Period (January 1, 2004–June 30, 2011) ____________________________ 16 Table 5.2. Station Summary Statistics of Fecal Coliform Data for Brushy Creek During the Cycle 2 Verified Period (January 1, 2004–June 30, 2011) ______________________________________ 18 Table 5.3. Summary of Fecal Coliform Data for Brushy Creek by Hydrologic Condition During the Cycle 2 Verified Period (January 1, 2004–June 30, 2011) ____________________________ 20 iv Florida Department of Environmental Protection FINAL TMDL Report: Perdido River and Bay Basin, Brushy Creek (WBID 4), Fecal Coliform, August 2012 Table 5.4. Calculation of Fecal Coliform Reductions for the Brushy Creek TMDL Based on the Hazen Method ____________________ 23 Table 6.1. TMDL Components for Fecal Coliform in Brushy Creek _________ 27 Table B.1. Estimated Agricultural Loading in the Brushy Creek Watershed ______________________________________________ 33 Table B.2. Estimated Number of Households and Dogs, Waste Produced (grams/day) by Dogs Left on the Land Surface, and Total Load of Fecal Coliform (counts/day) Produced by Dogs within the Brushy Creek WBID Boundary ________________ 34 Table B.3. Dog Population Density, Wasteload, and Fecal Coliform Density Based on the Literature (Weiskel et al. 1996) ___________ 34 Table B.4. Estimated Number of Households Using Septic Tanks and Estimated Septic Tank Loading within the Brushy Creek WBID Boundary _________________________________________ 36 Table B.5. Estimated Number of Septic Tanks and Septic Tank Failure Rates for Escambia County, 2003–10 ________________________ 38 List of Figures Figure 1.1. Location of the Brushy Creek (WBID 4) Watershed in the Perdido River and Bay Basin and Major Geopolitical and Hydrologic Features in the Area _____________________________ 2 Figure 1.2. Detailed View of the Brushy Creek (WBID 4) Watershed and Major Geopolitical and Hydrologic Features in the Area _________ 3 Figure 2.1. Fecal Coliform Concentration Trends in Brushy Creek for the Period of Record (1966–2011) ____________________________ 6 Figure 4.1. Principal Land Uses within the Brushy Creek WBID Boundary in 2009–10 _____________________________________ 11 Figure 5.1. Location of Water Quality Stations in Brushy Creek ____________ 13 Figure 5.2. Trends in Fecal Coliform Concentrations in Brushy Creek During the Cycle 2 Verified Period (January 1, 2004–June 30, 2011) __________________________________________________ 14 Figure 5.3a. Fecal Coliform Exceedances and Rainfall at All Stations in Brushy Creek by Month During the Cycle 2 Verified Period (January 1, 2004–June 30, 2011) ____________________________ 16 Figure 5.3b. Fecal Coliform Exceedances and Rainfall at All Stations in Brushy Creek by Season During the Cycle 2 Verified Period (January 1, 2004–June 30, 2011) ____________________________ 17 Figure 5.4. Spatial Fecal Coliform Concentration Trends in Brushy Creek by Station During the Cycle 2 Verified Period (January 1, 2004–June 30, 2011) ____________________________________ 18 v Florida Department of Environmental Protection FINAL TMDL Report: Perdido River and Bay Basin, Brushy Creek (WBID 4), Fecal Coliform, August 2012 Figure 5.5. Fecal Coliform Data for Brushy Creek by Hydrologic Condition During the Cycle 2 Verified Period (January 1,