1 Flint River Basin Regional Water Development and Conservation Plan March 20, 2006 Georgia Dept. of Natural Resources Environmental Protection Division Carol A. Couch Director Robin John McDowell Plan Coordinator 2 Table of Contents Introduction..................................................................................................................... 14 Acknowledgements........................................................................................................ 19 PART I: SUMMARY OF TECHNICAL FINDINGS AND EPD PERMITTING ACTIONS ..................................................................................... 21 A. Summary of technical findings ................................................................................ 21 B. EPD permitting and water resource management actions.................................... 23 PART II: STAKEHOLDER PROCESS AND RECOMMENDATIONS FOR REGULATION OF AGRICULTURAL WATER WITHDRAWALS ..................................................................................................... 37 SECTION 1: BACKGROUND AND FRAMEWORK ............................................... 37 1.1 Explanation and justification for the Flint Basin Plan.................................... 37 1.2 Agricultural permit and permit application trends............................................... 39 1.3 Conservation, development, and ecologic sustainability....................................... 41 1.3.1 Factors affecting maximum possible development.............................................. 43 1.3.2 Factors limiting maximum conservation ............................................................. 44 1.4 The Flint River Drought Protection Act................................................................. 45 SECTION 2: RECOMMENDED WATER RESOURCE MANAGEMENT AND PERMITTING STRATEGIES FOR THE FLINT RIVER BASIN........................... 47 2.1 General Plan goals .................................................................................................... 47 2.2 Stakeholder Advisory Committee ........................................................................... 48 2.3 Technical Advisory Committee .............................................................................. 49 2.4 Guiding principles of the Stakeholder Advisory Committee............................... 50 2.5 Conclusions about “safe yield” ................................................................................ 51 3 2.6 EPD regulatory limits.............................................................................................. 52 2.8 Consensus recommendations for permitting strategies......................................... 52 2.9 Stakeholder recommendations for regulatory and statutory reform .................. 55 PART III: TECHNICAL AND STATUTORY BACKGROUND OF PLAN RECOMMENDATIONS........................................................................... 58 SECTION 3: STATE OF THE BASIN’S NATURAL RESOURCES ....................... 58 3.1 Basin hydrography.................................................................................................... 58 3.2 Rainfall patterns: normal, drought, and long-term trends................................... 59 3.4 Surficial geology........................................................................................................ 62 3.5 Stream-aquifer interaction....................................................................................... 66 SECTION 4: FISH AND WILDLIFE RESOURCES OF THE LOWER FLINT RIVER BASIN ................................................................................................................ 68 4.1 Mussels....................................................................................................................... 68 4.2 Gulf striped bass ....................................................................................................... 72 SECTION 5: WATER USE IN THE FLINT RIVER BASIN .................................... 75 5.1 Agricultural water withdrawal permitting............................................................. 75 5.1.1 Application for a permit....................................................................................... 75 5.1.2 Application evaluation – ground-water withdrawal permits ............................... 76 5.1.3 Application evaluation – surface-water withdrawal permits ............................... 77 5.1.4 “Grandfathered” farm-use permits....................................................................... 78 5.1.5 Expiration, revocation, modification and transfer of agricultural permits........... 79 5.2 Historical agricultural water use in southwest Georgia........................................ 80 5.2.1 Extension irrigation surveys ................................................................................ 80 5.2.2 Subarea 4 and Flint Basin Sound Science Studies – Irrigated acreage................ 81 5.3 Municipal and industrial ground-water withdrawal permitting.......................... 90 5.3.1 Municipal and industrial ground-water permitting.............................................. 90 5.4 Municipal and industrial surface-water withdrawal permitting.......................... 93 4 5.5 Permitted municipal and industrial withdrawals .................................................. 95 SECTION 6: HYDROLOGIC MODELS IN THE LOWER FLINT RIVER BASIN ........................................................................................................................................... 99 6.1 Ground-water models............................................................................................... 99 6.1.1 Model area and boundaries .................................................................................. 99 6.1.2 Model application and results ............................................................................ 101 6.1.3 Water budget analysis........................................................................................ 102 6.1.4 Base flow reduction by HUC-12 and HUC-8 sub-basin.................................... 104 6.2 Surface-water models ............................................................................................. 120 6.2.1 Description of Model Scenarios......................................................................... 120 6.2.2 Model Results .................................................................................................... 122 6.3 Scenario Impact Evaluation................................................................................... 124 6.3.1 Discussion of In stream Flow Impact Criteria ................................................... 124 6.3.2 Aquatic Habitat Protection Streamflow Criteria................................................ 125 6.3.3 Water Quality Guidelines .................................................................................. 126 6.3.4 Computation of Criteria ..................................................................................... 127 6.3.5 Evaluation of In-Stream Flow Criteria ............................................................. 127 6.3.6 Water Quality Guidelines .................................................................................. 135 6.4 Interpretation of Scenario Impact Model Results ............................................... 137 SECTION 7: HYDROLOGIC EVALUATION OF SPRING CREEK, ICHAWAYNOCHAWAY, AND LOWER FLINT SUB-BASINS........................... 139 7.1 Ichawaynochaway Creek sub-basin ...................................................................... 139 7.2 Spring Creek sub-basin .......................................................................................... 144 7.2.1 Basin hydrography............................................................................................. 144 7.3 Lower Flint River sub-basin .................................................................................. 150 SECTION 8: ECONOMIC STATUS OF THE LOWER FLINT RIVER BASIN . 153 8.1 Agriculture............................................................................................................... 153 8.2 Manufacturing and other sectors .......................................................................... 154 8.3 Modeled economic impacts of reducing irrigation .............................................. 154 SECTION 9 : WATER CONSERVATION IN THE FLINT RIVER BASIN ....... 162 5 8.1 Definition ................................................................................................................ 162 9.2 Proposed strategies ................................................................................................. 163 GLOSSARY................................................................................................................... 166 BIBLIOGRAPHY......................................................................................................... 171 APPENDIX I: SURFACE-WATER MODEL AND APPLICATION................... 177 APPENDIX II: GROUND-WATER MODEL AND APPLICATION .................... 237 6 List of Figures Figure 0.1: The Flint River Basin and sub-basins............................................................. 18 Figure 0.2. Classification of HUC-12 watersheds in the lower Flint River Basin............ 25 Figure 0.3. Classification of HUC-12 watersheds in the Ichawaynochaway Creek sub- basin. ......................................................................................................................... 27 Figure 0.4. Classification