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BASINS and WEPP Climate Assessment Tools (CAT): Case Study Guide to Potential Applications

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BASINS and WEPP Climate Assessment Tools (CAT): Case Study Guide to Potential Applications EPA/600/R-11/123a November, 2011 BASINS and WEPP Climate Assessment Tools (CAT): Case Study Guide to Potential Applications NOTICE THIS DOCUMENT IS A DRAFT. This document is distributed solely for the purpose of pre- dissemination peer review under applicable information quality guidelines. It has not been formally disseminated by EPA. It does not represent and should not be construed to represent any Agency determination or policy. Mention of trade names or commercial products does not constitute endorsement or recommendation for use Global Change Research Program National Center for Environmental Assessment Office of Research and Development U.S. Environmental Protection Agency Washington, DC 20460 Draft – Do not cite or quote DISCLAIMER This document is distributed solely for the purpose of pre-dissemination peer review under applicable information quality guidelines. It has not been formally disseminated by EPA. It does not represent and should not be construed to represent any Agency determination or policy. Mention of trade names or commercial products does not constitute endorsement or recommendation for use. Draft – Do not cite or quote 2 FOREWORD Draft – Do not cite or quote 3 AUTHORS AND REVIEWERS The National Center for Environmental Assessment (NCEA), Office of Research and Development, was responsible for preparing this external review draft report. Preparation of an earlier draft report was conducted by AQUA TERRA Consultants, under EPA Contract EP-C-06-029. AUTHORS AQUA TERRA Consultants, Decatur, GA Paul Hummel Paul Duda Tong Zhai Elizabeth Wolfram U.S. Environmental Protection Agency, National Center for Environmental Assessment, Global Change Research Program, Washington, DC Thomas Johnson Meredith Warren REVIEWERS We are very grateful for the many excellent comments and suggestions about improving this report provided by EPA reviewers Steve Kramer, Philip Morefield, Julie Reichert, and Christopher Weaver. Draft – Do not cite or quote 4 CONTENTS LIST OF TABLES ........................................................................................................................................ 6 LIST OF FIGURES ...................................................................................................................................... 8 LIST OF ABBREVIATIONS ..................................................................................................................... 10 EXECUTIVE SUMMARY ........................................................................................................................ 12 1. INTRODUCTION .............................................................................................................................. 14 2. BASINS AND WEPP CLIMATE ASSESSMENT TOOLS .............................................................. 17 3. CASE STUDIES ................................................................................................................................. 24 3.1. Introduction ............................................................................................................................. 24 3.2. Climate Change Impacts on Annual and Seasonal Nutrient Loading and Streamflow in the Upper Mississippi River Basin, Raccoon River, IA ........................................................................... 27 3.3. Managing Climate Change Impacts on Stormwater Runoff from an Urban Redevelopment Site in Upper Roanoke River, VA ...................................................................................................... 46 3.4. Climate change impacts on sediment erosion from fields under corn and soy production, including BMP analysis, in Blue Earth County, MN .......................................................................... 57 3.5. Precipitation Pattern Change Impacts on Water Quality in the Tualatin River, OR ............... 67 3.6. Assessing the impact of increased drought in Sespe Creek, CA Watershed ........................... 74 3.7. Sensitivity of Stormwater to Changes in Precipitation Volume, Event Intensity, and Impervious Cover in the Western Branch of the Patuxent River, MD ............................................... 81 3.8. Model Limitations ................................................................................................................... 89 4. CONCLUDING COMMENTS ........................................................................................................... 91 REFERENCES ........................................................................................................................................... 93 APPENDIX A ............................................................................................................................................. 98 Draft – Do not cite or quote 5 LIST OF TABLES Table 3.1. Summary of case studies presented in this report. ..................................................................... 25 Table 3.2. Land use summary for Raccoon River watershed. .................................................................... 29 Table 3.3. Raccoon River model calibration statistics for yearly results. NSE: Nash-Sutcliffe Efficiency coefficient; PB: percent bias, RMSE: root mean square error. ............................................... 29 Table 3.4. Mean annual streamflow (cms) for all combinations of temperature and precipitation change. Baseline condition shown in box. ............................................................................................ 32 Table 3.5. Mean annual nitrogen load (kg/ha/yr) for all combinations of temperature and precipitation change. Baseline condition shown in box. .............................................................................. 33 Table 3.6. Mean annual phosphorous load (kg/ha/yr) for all combinations of temperature and precipitation change. Baseline condition shown in box. .............................................................................. 33 Table 3.7. Mean annual sediment load (tonnes/ha/yr) for all combinations of temperature and precipitation change. Baseline condition shown in box. ......................................................... 33 Table 3.8. Mean annual evapotranspiration (cm/yr) for all combinations of temperature and precipitation change. Baseline condition shown in box. .............................................................................. 34 Table 3.9. NARCCAP climate models used to develop the case study scenarios. ..................................... 36 Table 3.10. Mean monthly streamflow (cms) for all scenarios. .................................................................. 43 Table 3.11. Mean monthly nitrogen load (kg/ha) for all scenarios. ............................................................ 43 Table 3.12. Mean monthly phosphorous load (kg/ha) for all scenarios. ..................................................... 43 Table 3.13. Mean monthly sediment load (tonnes/ha) for all scenarios. .................................................... 43 Table 3.14. Total and aMean annual precipitation, temperature, streamflow, TN, TP, and TSS loads for all scenarios. ................................................................................................................................. 44 Table 3.15. Baseline land use summary for the commercial redevelopment site. ...................................... 47 Table 3.16. Event precipitation, mean total inflow, and concentrations of TP and TSS for the baseline and climate change scenarios. ........................................................................................................ 50 Table 3.17. Event mean total inflow (cms) under different rainfall intensities and stormwater management strategies. Flow values greater than the threshold are highlighted in orange. ......................... 53 Table 3.18. Soy spring chisel plow land management specifications in WEPPCAT. ................................ 59 Table 3.19. Corn spring chisel land management specifications in WEPPCAT. ....................................... 59 Table 3.20. Mean annual sediment yield (tonnes/ha/yr) for corn production under conditions of changing climate. Scenarios named to reflect changes in precipitation volume and intensity; V = volume, I = intensity, numerical value reflects percent change from baseline........................ 60 Table 3.21. Mean annual sediment yields (tonnes/ha/yr) for soy production under conditions of changing climate. Scenarios named to reflect changes in precipitation volume and intensity; V = volume, I = intensity, numerical value reflects percent change from baseline........................ 61 Table 3.22. Corn fall mulch till management characteristics in WEPPCAT. ............................................. 63 Table 3.23. Corn no-till management characteristics in WEPPCAT. ......................................................... 63 Table 3.24. Sediment yield (tonnes/ha/yr) resulting from corn production under all climate change and land use scenarios. NB=no buffer, GB3=3 meter grass (generic) buffer, GB=6 meter grass (generic) buffer, GB9=9 meter grass (generic) buffer, FB3=3 meter forest buffer, FB6=6 meter forest buffer, FB9-9 meter forest buffer, V0=no change in volume, V20=20 percent increase in volume, V20 +I10=20 percent increase in volume and 10 percent increase in rainfall intensity. ...................................................................................................................... 64 Table 3.25. Sediment yield (tonnes/ha/yr) results
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