State of Ohio Environmental Protection Agency Division of Surface Water Total Maximum Daily Loads for the Big Walnut Creek Watershed Tributary to Alum Creek, Delaware County (photo courtesy of Friends of Alum Creek and Tributaries (FACT)) Final Report August 19, 2005 Bob Taft, Governor Joseph P. Koncelik, Director TABLE OF CONTENTS 1.0 Introduction ..................................................... 1 2.0 Waterbody Overview .............................................. 7 2.1 Study Area Description ..................................... 7 2.2 Water Quality Standards .................................... 9 2.3 Causes and Sources of Impairment .......................... 15 3.0 Priority Causes of Impairment and Target Identification ................ 23 3.1 Nutrient Enrichment....................................... 23 3.2 Habitat Alteration and Siltation .............................. 24 3.3 Organic Enrichment/Dissolved Oxygen ........................ 25 3.4 Pathogens .............................................. 26 4.0 TMDL Development .............................................. 28 4.1 Methods of TMDL Development Used Basin Wide ............... 29 4.1.1 Habitat, Siltation, and the QHEI ....................... 29 4.1.2 Pathogens ....................................... 32 4.2 TMDL Development for the Upper Big Walnut Creek Watershed .... 35 4.3 TMDL Development for the Lower Big Walnut Creek Watershed .... 36 4.3.1 Nutrients.......................................... 36 4.3.2 Bacteria........................................... 39 4.4 Critical Condition ......................................... 42 4.4.1 Nutrients.......................................... 42 4.4.2 Pathogens ........................................ 42 4.4.3 Habitat and Sediment ................................ 42 4.5 Margin of Safety ......................................... 43 4.5.1 Nutrients.......................................... 43 4.5.2 Pathogens ........................................ 44 4.5.3 Habitat and Sediment ................................ 44 4.6 Future Growth........................................... 44 5.0 Water Quality Assessment and TMDLs .............................. 46 5.1 Upper Big Walnut Creek (Assessment Unit 05060001 - 130) ....... 46 5.1.1 Assessment Results ................................ 46 5.1.2 Causes and Sources of Impairment ..................... 50 5.1.3 Deviation From Target .............................. 51 5.1.4 Existing Loads, Loading Capacity and Allocations ......... 53 5.1.5 Habitat and Sediment TMDLs ......................... 60 5.2 Lower Big Walnut Creek (Assessment Unit 05060001 - 140) ....... 62 5.2.1 Assessment Results ................................ 62 5.2.2 Causes and Sources of Impairment ..................... 68 5.2.3 Deviation From Target............................... 69 5.2.4 Existing Loads, Loading Capacity and Allocations .......... 71 5.2.5 Habitat and Sediment TMDLs ......................... 78 5.3 Upper Alum Creek (Assessment Unit 05060001 - 150) ............ 80 5.3.1 Assessment Results ................................ 80 5.3.2 Causes and Sources of Impairment ..................... 82 5.3.3 Deviation From Target............................... 83 5.3.4 Existing Loads, Loading Capacity and Allocations .......... 84 5.3.5 Habitat and Sediment TMDLs ......................... 89 5.4 Lower Alum Creek (Assessment Unit 05060001 - 160) ............ 91 5.4.1 Assessment Results ................................ 91 5.4.2 Causes and Sources of Impairment ..................... 94 5.4.3 Deviation From Target............................... 95 5.4.4 Existing Loads, Loading Capacity and Allocations .......... 95 5.4.5 Habitat and Sediment TMDLs ........................ 100 6.0Public Participation............................................. 102 7.0 Big Walnut Creek Implementation Strategy ......................... 104 7.1 Reasonable Assurrances .................................. 104 7.1.1 Reasonable Assurrances Summary ................... 105 7.1.2 Point Source Controls .............................. 105 7.1.3 Nonpoint Source Controls ........................... 106 7.2 Process for Monitoring and Revision ......................... 109 References ....................................................... 110 APPENDICES Appendix A Qualitative Habitat Evaluation Index Evaluation Sheet Appendix B TMDL Development for the Lower Alum Creek and Lower Big Walnut Creek Watersheds Appendix C Model Development for Upper Alum Creek and Upper Big Walnut Creek Appendix D Big Walnut Creek TMDL, 2004 Integrated Report Listing Appendix E Responses to Public Comments TABLES Table 1.A. Summary of the Big Walnut Creek TMDL ................... 2 Table 2.A. Summary of Ohio Water Quality Standards ................. 12 Table 2.B. Causes & Sources of Impairment in the Big Walnut Creek Basin......................................... 16 Table 3.1.A. WWH TP Targets for the Eastern Corn Belt Plains Ecoregion . 24 Table 4.1.A. Details of Habitat and Sediment TMDLs ................... 31 Table 4.3.A. Summary of Nutrient TMDL Development.................. 37 Table 4.3.B. Summary of pathogen TMDL development for the lower Big Walnut Creek................................ 40 Table 4.6.A. Population Growth Figures for Big Walnut Creek Counties ..... 45 Table 5.1.A Aquatic life use attainment status of the Big Walnut Creek basin, June-October, 2000. ........................ 48 Table 5.1.B. Deviation from Target in HUC 05060001-130, Upper Big Walnut Creek..................................... 52 Table 5.1.C. Existing Point Source Loads ............................ 55 Table 5.1.D Existing Non-Point Source Loads ........................ 56 Table 5.1.E. Total Existing Load, TMDL, Allocations .................... 57 Table 5.1.F. Point Source Allocations ............................... 58 Table 5.1.G Non-point Source Allocations............................ 59 Table 5.1.H Existing and Target Habitat and Sediment Conditions ......... 61 Table 5.2.A Aquatic life use attainment status of the Big Walnut Creek basin, June-October, 2000. ........................ 66 Table 5.2.B. Deviation from Target in HUC 05060001-140, Big Walnut and Blacklick Creeks .................................. 70 Table 5.2.C. Existing Point Source Loads in HUC 05060001-140 .......... 72 Table 5.2.D Existing Non-Point Source Loads in HUC 05060001-140 ...... 73 Table 5.2.E. Total Existing Load, TMDL, Allocations for HUC 05060001-140 . 74 Table 5.2.F. Point Source Allocations for HUC 05060001-140 ............ 75 Table 5.2.G Non-point Source Allocations for HUC 05060001-140 ......... 76 Table 5.2.H MS4 Wasteload Allocations and Surface Runoff Allocations for HUC 05060001-140 ....................... 77 Table 5.2.I Existing and Target Habitat and Sediment Conditions ......... 79 Table 5.3.A Aquatic life use attainment status of the Big Walnut Creek basin, June-October, 2000. ........................ 81 Table 5.3.B. Deviation from Target in HUC 05060001-150, Upper Alum Creek 83 Table 5.3.C. Existing Point Source Loads in HUC 05060001-150 .......... 84 Table 5.3.D Existing Non-Point Source Loads in HUC 05060001-150 ...... 85 Table 5.3.E. Total Existing Load, TMDL, Allocations for HUC 05060001-150 . 86 Table 5.3.F. Point Source Allocations for HUC 05060001-150 ............ 87 Table 5.3.G Non-point Source Allocations for HUC 05060001-150 ......... 88 Table 5.3.H Existing and Target Habitat and Sediment Conditions ......... 90 Table 5.4.A Aquatic life use attainment status of the Big Walnut Creek basin, June-October, 2000. .................................. 93 Table 5.4.B. Deviation from Target in HUC 05060001-160, Lower Alum Creek, Lower Big Walnut Creek ............................... 95 Table 5.4.C. Existing Point Source Loads in HUC 05060001-160 .......... 96 Table 5.4.D Existing Non-Point Source Loads in HUC 05060001-160 ...... 97 Table 5.4.E. Total Existing Load, TMDL, Allocations for HUC 05060001-160 . 97 Table 5.4.F. Point Source Allocations for HUC 05060001-160 ............ 98 Table 5.4.G Non-point Source Allocations for HUC 05060001-160 ......... 98 Table 5.4.H MS4 Wasteload Allocations and Surface Runoff Allocations for HUC 05060001-160 ....................... 99 Table 5.4.I Existing and Target Habitat and Sediment Conditions ........ 101 Table 7.1.A Recommended NPDES Permit Limits In the Big Walnut Creek TMDL............................................. 105 Table 7.1.B Required Reductions in Pathogen Loading in the Big Walnut Creek Watershed. ........................................ 108 FIGURES Figure 1. Land Use in the Big Walnut Creek Watershed ..................... 11 Figure 2. Upper Big Walnut Creek Watershed ............................. 13 Figure 3. Lower Big Walnut Creek Watershed ............................ 14 Figure 4. Allowable Daily Fecal Coliform Load ............................. 60 Figure 5. Allowable Daily Fecal Coliform Load ............................. 78 Figure 6. Allowable Daily Fecal Coliform Load ............................. 89 Figure 7. Allowable Daily Fecal Coliform Load ............................ 100 ACKNOWLEDGMENTS The following Ohio EPA staff provided technical services for this project: C Biology and Chemical Water Quality - Mike Bolton, Jeff Bohne, Paul Vandermeer C Point Source Issues - Larry Korecko, John Owen C Nonpoint Source Issues - Vince Mazieka C Water Quality Modeling - James Connon, Matt Fancher C Project Leader - Mike Gallaway Many full- and part-time staff participated in field monitoring. Big Walnut Creek Watershed TMDLs 1.0 Introduction The Clean