1. Invest 2.2.1 Nutrient Retention model Yonas Ghile

2. Why Nutrient Retention model?  ~ 14,000 people die daily  Global water treatment cost ~$24.6 billion/year  Dead fish zone in the Gulf of Mexico ~5, 000 mil 2  Non-Point Source is major cause

3. Biophysical Inputs Land Use/Land Cover Nutrient loading, Retention capacity, root depth, crop coefficient Topography Digital elevation model, slope threshold Climate Precp, PET Soils Soil depth, PAWC Watershed Areas Main and sub for point of interest and water quality analysis

4. Biophysical Inputs...

5. 1. Estimate Water yield 3. Estimate Pollutant Load value 4. Estimate nutrient retained 5. Estimate pollutant reached the stream wheat Corn forest 2. Calculate flow direction

6. Valuation Time Loading Critical Loading 6. Estimate Avoided treatment costs

7. Some Questions  Where are the pollutant sources?  Where are the pollutant retention areas?  How much is retained?  What is the Value of this retention?

8. Informs Policy Makers to  Protect areas that retain most  Design management practices that lead to maximum retention  Create payment programs to get most return on investment  Identify services that conflict with water purification  How much retention will we gain or lose under future management or conservation plans?

9. Strengths  Uses readily available and minimum data  Simple, applicable and spatially explicit  Link the biophysical functions to economic values  Values each parcel on the landscape

10. Limitations  All bio-physio-chemical processes are lumped in one number export coefficient  Annual basis, misses seasonality  No instream processes and point sources  Less relevant to areas dominated by infiltration excess  Assess one pollutant per run  No saturation in uptake

11. Model Calibration and Testing  Sensitivity Analysis to identify most sensitive parameters  Model Calibration using long term average actual data  Find crop coefficient and root depth within acceptable ranges  Model parameter (Zhang constant)  Find export coefficients and vegetation efficiencies within acceptable ranges  Validate Model by conducting comparisons with observed data or other model output

12. Phosphorus loads (kg/yr) Hainan Island, China

13. Nitrogen Loads (kg/yr)

14. Hands-on Session  Run the water yield model

15. Hands-on Session  Run the nutrient retention model

16. Hands-on Session  Run the valuation model

17. Hainan Island, China Actual (2008) IEM RNF No Expansion Increase No change Decline

18. Baoxing, China Retained TN Retained TP High Low High Low

19. Scenarios for Mine Expansion in Columbia Current Mines Permits Granted Permits Pending All possible permits

20. Columbia Permits GrantedPermits Pending All possible Permits Change in Nitrogen Export (kg/ha/yr)

21. Columbia High Impact Zones should avoided Permits Granted Permits Pending All possible Permits

22. Coming up soon  Improve vegetation retention rates  Include Point source pollutant  Include bacterial contamination  Improve pollutant load adjustment  Tier 2 nutrient retention model

23. Hands-on Session Any idea how you would use the Nutrient Retention Model in your work?

24. How Does it Work? Pollutant Load Value: Hydrologic Sensitivity Score: Adjusted Loading Value:

25. How Does it Work?... forest Stream Pollutant input Y wheat Corn forest

26. How Does it Work?... Removal of polluntats by vegetation and soil along the flowpaths is calculated as follows

27. Valuation Time Loading Critical Loading