1. Water Quality Modeling: Estimating Pollutant Load Reductions for Project Reporting Scott Daly Utah Division of Water Quality 801.536.4333 sdaly@utah.gov

2. Objective UAFRRI – Utah Animal Feedlot Runoff Risk Index –Overview –Data Inputs STEPL – Spreadsheet Tool for Estimating Pollutant Loads 1.Overview 2.Data Inputs 3.Model Setup 4.Limitations 5.Data Sources WQ Models and Project Planning Discussion

3. Utah Animal Feedlot Runoff Risk Index (UAFRRI) MS Excel spreadsheet Nutrient loading and load reduction estimates (N, P, and BOD5) Feedlot Risk Assessment

5. Spreadsheet Tool for Estimating Pollutant Loads (STEPL) MS Excel spreadsheet –Easy to use –Inputs can be modified by user (optional) Calculates nutrient (N, P, and BOD5) and sediment loads by land use type Calculates expected load reductions Data driven and highly empirical

6. STEPL Process Land Uses Animals Soil and USLE Parameters User Input Septic Systems Direct Discharges Load Nitrogen Phosphorus BOD Sediment Sheet/Rill Erosion Runoff BMPs/LIDs Load Reduction Processes Gully/ Streambank Erosion Groundwater Pollutant Transport Precipitation Irrigation

7. STEPL Web Site URL: http://it.tetratech-ffx.com/stepl Link to download

8. STEPL Main Program Run STEPL executable program (STEPL.exe) Start All Programs STEPL

9. STEPL Spreadsheet Composed of four worksheets

10. Data Input

11. Universal Soil Loss Equation (RUSLE) USLE = R*K*LS*C*P Where: R = rainfall and runoff factor K = soil erodibility factor LS = slope length and steepness factor C = cover management factor P = support practice factor

12. USLE – LS Factor

13. Typical USLE C and P Values Support Practice Factor

14. Optional Input Data

15. SCS Curve Number – Hydrologic Soil Group Group A –Low overland Flow; high infiltration capacity; well-drained (Sand and Gravel) Group B –Moderate minimum infiltration capacity; moderately- to well- drained; moderately-course grained (Sandy Loam) Group C – Low minimum infiltration capacity; moderately fine- to fine-grained soils Group D – very low infiltration capacity; high overland flow potential (Clay)

16. Curve Numbers for Arid and Semi- arid Rangelands Hydrologic Soil Hydrologic Land Use/CoverConditionGroupA B C D ------------------------------------------------------------------------------------------------------------------------------------------- Herbaceous - grass, weeds & low-Poor /a-808793 growing brush; brush the minorFair-718189 componentGood-627485 Oak/aspen - oak brush, aspen,Poor-667479 mountain mahogany, bitter brush,Fair-485763 maple and other brushGood-304148 Pinyon/juniper - pinyon, juniper orPoor-758589 both; grass understoryFair-587380 Good-416171 Sagebrush with grass understoryPoor-678085 Fair-516370 Good-354755 Desert scrub - saltbush, greasewood,Poor63778588 creosotebrush, blackbrush, bursage,Fair55728186 palo verde, mesquite and cactusGood49687984 ------------------------------------------------------------------------------------------------------------------------------------ a. Poor: < 50% ground cover (litter, grass and brush overstory); Fair: 50 to 75% ground cover; Good: 75% ground cover. SCS Curve Number Computations.pdf Appendix A Table 2-2

17. CN - Antecedent Moisture Conditions

18. Populate STEPL Input Tables

19. BMPs

20. Urban BMP Tool

21. Gully/Streambank Loading

22. Add New Data to BMP List In STEPL customized menu, click “View/Edit BMP List” BMP List worksheet is shown, add or delete BMPs

23. BMP Efficiency Calculator

24. Add New Data to BMP List Click “Update BMP Data” button to update the BMP selections in the BMPs worksheet Click “Save Updates” to save changes to text files (comma delimited) –C:or D:\Stepl\Support\AllBMPstepl.csv –C: or D:\Stepl\Support\AllBMP.csv New BMP added! (BMPs worksheet) Update BMP button (BMPList worksheet) New BMP added!

25. STEPL BMP Calculator Calculates combined efficiency of a BMP train for a given land use.

26. STEPL BMP Calculator Filter strip Reduced tillage Series Parallel Reduced tillageConventional tillage Settling Basin Reduced tillageConventional tillage Combination Filter strip

27. STEPL BMP Calculator Describe schematically BMP configuration –Number and linkages –BMP type and efficiency –Land use area Calculate combined efficiency Enter calculated efficiency in table 7 on the BMP tab 1. Add BMP box 4. Calculate combined efficiency 5. Delete Connection 2. Draw Connection 3. Move BMP box

28. BMP Calculator - Series Reduced Tillage Filter Strip Load 3 1 2

29. BMP Calculator - Parallel Streambank Stabilization Contour Farming Load 3 1 2 Each box represents 100 ac

30. Populate STEPL BMP Tables

31. Total Load

32. Graphs

33. Other Ways to Use STEPL Model changes in land use and runoff before and after BMPs instead of modeling efficiencies Estimate BMP efficiencies BMP efficiency = (Pre BMP load – Post BMP load) / Pre BMP load Project planning

34. STEPL as a Project Planning Tool Compare two projects to determine which has the most potential for load reduction Compare multiple BMPs within the same project area

35. Model Limitations Driven by empirical relationships –Emphasis for project-specific data Model calibration/validation –Not easy to calibrate Designed to produce “rough” loading estimates, NOT accurate or precise estimates

36. Discussion

37. Data Resources Table 1. Input watershed land use area (ac) and precipitation (in) 1. Precipitation: (a). Local observation (b). http://www.wrcc.dri.edu/ (c). http://www.wcc.nrcs.usda.gov/snow/ (d). nws.noaa.gov Table 4. Modify the Universal Soil Loss Equation (USLE) parameters 1.K Factor - http://websoilsurvey.nrcs.usda.gov/app/HomePage.htm 2.LS Factor – Field measurements for slope length (L) and slope (S), then consult the following tables. USDA Agricultural Handbook 703: Tables 4-1 through 4-9. 3.Cover Management Factor – USLE Appendix A - Cover Managment Factor.doc and http://www.iwr.msu.edu/rusle/doc/cfactors.pdf 4.Support Practice Factor – http://www.omafra.gov.on.ca/english/engineer/facts/00-001.htm Table 5 Table 5. Select average soil hydrologic group (SHG) 1.Soil Hydrologic Group = Hydrologic Soil Group http://websoilsurvey.nrcs.usda.gov/app/HomePage.htm

38. Table 6. Reference runoff curve number (may be modified) 1. SCS Runoff Curve Number Computations.pdf, Appendix A Table 2-2 Data Resources