1. ©2003 Institute of Water Research, all rights reserved Water Quality Modeling for Ecological Services under Cropping and Grazing Systems Da Ouyang Jon Bartholic Institute of Water Research Michigan State University

2. ©2003 Institute of Water Research, all rights reserved Water Quality Modeling Surface Water Quality - Soil Erosion - Sediment Delivery - Nutrient Loading (P, N) Groundwater Quality - Pesticide / Nutrient Leaching

3. ©2003 Institute of Water Research, all rights reserved Water Quality Modeling Surface Water Quality Modeling - RUSLE - SEDMOD - AGNPS / SWAT - MARI & Nutrient Loading Coefficients Groundwater Quality Modeling - WIN-PST (Pesticide Screening Tool)

4. ©2003 Institute of Water Research, all rights reserved RUSLE Revised Universal Soil Loss Equation

5. ©2003 Institute of Water Research, all rights reserved RUSLE A = R K LS C P A = Soil loss in tons per acre per year R = Rainfall-runoff erosivity factor K = Soil erodibility factor S = Slop steepness factor L = Slope length factor C = Cover-management factor P = Support practice factor

6. ©2003 Institute of Water Research, all rights reserved SEDMOD Spatially Explicit Sediment Delivery Model

7. ©2003 Institute of Water Research, all rights reserved Spatially Explicit Sediment Delivery Model (SEDMOD) SDR = 39 A –1/8 +  DP Where SDR = sediment delivery ratio A = watershed area in square km  DP = difference between the composite delivery potential and its mean value

8. ©2003 Institute of Water Research, all rights reserved SEDMOD Delivery Potential composite layer in GRID DP = (SG)r(SG)w + (SS)r(SS)w + (SR)r(SR)w + (SP)r(SP)w + (ST)r(ST)w + (OF)r(OF)w Where SG = slope gradient SS = slope shape SR = surface roughness SP = stream proximity ST = soil texture OF = overland flow index r = parameter rating (1-100) w = weighting factor (0-1)

9. ©2003 Institute of Water Research, all rights reserved Sediment Yield SY = A * SDR Where SY = Sediment Yield A = Gross Soil Loss SDR = Sediment Delivery Ratio

10. ©2003 Institute of Water Research, all rights reserved WIN-PST Window-Based Pesticide Screening Tool

11. ©2003 Institute of Water Research, all rights reserved WIN-PST (Window-Based Pesticide Screening Tool) Assess relative likelihood of pesticide loss from -field boundaries via runoff -below the root zone via percolation Overall risk ratings are based on a matrix of -Pesticide (toxicity, application method and rate) -Soil (Soil texture, hydrologic group, slope, water table)

12. ©2003 Institute of Water Research, all rights reserved MARI Manure Application Risk Index

13. ©2003 Institute of Water Research, all rights reserved MARI (Manure Application Risk Index) Identify areas where winter-time spreading of manure may cause potential risk for runoff losses of N or P 12 Field parameters: Soils; Slope; Soil Test P; Concentration Water Flow; Residue/Cover; Surface Water Setback; Vegetative Buffer Width; Manure P / N Application Rate; Manure Application Method; Others.

14. ©2003 Institute of Water Research, all rights reserved Data DEM (Digital Elevation Model, 30-meter) SSURGO Soil Data (Soil Survey Geographic Database) Landuse / Land cover data Crop Residue Management Data (CTIC) Other - EPA BASINS

15. Data and Tools for Water Quality Modeling

16. Previous Studies

17. Stony Creek Study

18. Corn-Corn Corn-Soybean Soybean-Wheat Erosion 182,000 154,000 67,000 Sediment 61,000 52,000 28,000 Phosphorus 129 112 59 Estimated soil loss, sediment and phosphorus in Stony Creek Watershed (tons / year)

19. Measured Phosphorus and Suspended Solids In Sycamore Creek Watershed, MI

20. Findings from other study (Randall et al. 1997) NO 3 – losses from row crops (corn, soybean) were 30-50 times greater than losses from perennial crops such as Alfalfa

21. Atrazine Leaching Risk Mapping

23. Great Lakes Basin

24. ©2003 Institute of Water Research, all rights reserved Estimated Potential Sediment Loading Contributed from Cropland (tons/yr.)

26. Questions & Discussion (C = Cover-management factor)