Final Total Maximum Daily Loads for Dissolved Oxygen in Hollin Creek (WBID 1475) and Dissolved Oxygen and Nutrients in Anclote River Bayou Complex (Spring Bayou) (WBID 1440A) and Biochemical Oxygen Demand, Dissolved Oxygen, and Nutrients in Anclote River (WBIDs 1440 & 1440F) July 2013 Final TMDL: Anclote River July 2013 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 the Total Maximum Daily Load (TMDL) for biochemical oxygen demand, dissolved oxygen, and nutrients in the Springs Coast Basin (WBIDs 1475, 1440A, 1440, 1440F). Subsequent actions must be consistent with this TMDL. _____________/s/_____________________________ __7/7/2013__ James D. Giattina, Director Date Water Protection Division 2 Final TMDL: Anclote River July 2013 TABLE OF CONTENTS 1.0 INTRODUCTION.......................................................................................................................... 1 2.0 PROBLEM DEFINITION ............................................................................................................ 2 3.0 WATERSHED DESCRIPTION ................................................................................................... 3 3.1 CLIMATE .......................................................................................................................................................... 4 3.2 HYDROLOGIC CHARACTERISTICS ..................................................................................................................... 4 3.3 LAND USE ........................................................................................................................................................ 4 4.0 WATER QUALITY STANDARDS/TMDL TARGETS ............................................................ 9 4.1 DESIGNATED USES ........................................................................................................................................... 9 4.2 WATER QUALITY CRITERIA .............................................................................................................................. 9 4.3 NUTRIENT CRITERIA ........................................................................................................................................ 9 4.3.1 Narrative Nutrient Criteria .................................................................................................................. 10 4.3.2 Inland Nutrient Criteria for streams .................................................................................................... 10 4.3.3 Inland Nutrient Criteria for estuaries with effective criteria ............................................................... 11 4.3.4 Inland Nutrient Criteria for lakes ........................................................................................................ 11 4.3.5 Springs Nutrient Criteria ..................................................................................................................... 12 4.4 DISSOLVED OXYGEN CRITERIA ...................................................................................................................... 12 4.5 BIOCHEMICAL OXYGEN DEMAND CRITERIA .................................................................................................. 12 4.6 NATURAL CONDITIONS .................................................................................................................................. 12 5.0 WATER QUALITY ASSESSMENT ......................................................................................... 12 5.1 WATER QUALITY DATA ................................................................................................................................. 13 5.1.1 Dissolved Oxygen ................................................................................................................................ 13 5.1.2 Biological Oxygen Demand ................................................................................................................. 13 5.1.3 Nutrients .............................................................................................................................................. 13 5.1.3.1 Total Nitrogen ................................................................................................................................................. 13 5.1.3.2 Total Phosphorus ............................................................................................................................................. 14 5.1.3.3 Chlorophyll-a .................................................................................................................................................. 14 6.0 SOURCE AND LOAD ASSESSMENT ..................................................................................... 29 6.1 POINT SOURCES ............................................................................................................................................. 29 6.1.1 Wastewater/Industrial Permitted Facilities ......................................................................................... 29 6.1.2 Stormwater Permitted Facilities/MS4s ................................................................................................ 30 6.2 NONPOINT SOURCES ...................................................................................................................................... 32 6.2.1 Urban Areas......................................................................................................................................... 32 6.2.2 Pastures ............................................................................................................................................... 34 6.2.3 Clear cut/Sparse .................................................................................................................................. 35 i Final TMDL: Anclote River July 2013 6.2.4 Forests ................................................................................................................................................. 35 6.2.5 Water and Wetlands ............................................................................................................................. 35 6.2.6 Quarries/Strip mines ............................................................................................................................ 35 7.0 ANALYTICAL APPROACH ..................................................................................................... 36 7.1 MECHANISTIC MODELS .................................................................................................................................. 36 7.1.1 Loading Simulation Program C++ (LSPC)......................................................................................... 36 7.1.2 Environmental Fluids Dynamic Code (EFDC) .................................................................................... 41 7.1.3 Water Quality Analysis Simulation Program (WASP7) ...................................................................... 48 7.2 SCENARIOS ..................................................................................................................................................... 58 7.2.1 Current Condition ................................................................................................................................ 58 7.2.2 Natural Condition ................................................................................................................................ 58 8.0 TMDL DETERMINATION ....................................................................................................... 66 8.1 CRITICAL CONDITIONS AND SEASONAL VARIATION ...................................................................................... 68 8.2 MARGIN OF SAFETY ....................................................................................................................................... 68 8.3 WASTE LOAD ALLOCATIONS ......................................................................................................................... 68 8.3.1 Wastewater/Industrial Permitted Facilities ......................................................................................... 68 8.3.2 Municipal Separate Storm Sewer System Permits ............................................................................... 69 8.4 LOAD ALLOCATIONS ...................................................................................................................................... 69 9.0 RECOMMENDATIONS/IMPLEMENTATION ..................................................................... 70 10.0 REFERENCES ............................................................................................................................. 71 ii Final TMDL: Anclote River July 2013 LIST OF FIGURES Figure 2.1 Location of impaired WBIDs in the Anclote River basin....................................... 2 Figure 3.1 Land use of impaired WBIDs in the Anclote River basin. ..................................... 5 Figure 3.2 Aerial photograph illustrating contributing subwatershed boundaries and impaired WBIDs. ……………………………………………………………………………………..7 Figure 5.1 Water quality monitoring station locations for WBID 1440 ................................ 17 Figure 5.2 Water quality monitoring station locations for WBID 1440A .............................. 17 Figure