1. Water Quality Index for Runoff from Agricultural Fields (WQIag) By Harbans Lal, Environmental Engineer Shaun McKinney, Team Leader National Water Quality/Quantity Team USDA/NRCS-WNTSC Portland, OR Helping People Help Land

2. Definition Traditional Usage Review Paper ( Water Efficiency Magazine ) Water Efficiency Magazine WQIag (Components & Description) WQIag ( A web-based System) WQI (Water Quality Index)

3. What it is ? Felt Need ( Evaluating conservation practices ) Purpose / benefits Comparative assessment over time & space Not a substitute for monitoring/measurement Evaluating effects of conservation practices Cost effective and easy to use Flexible/site-specific adjustments possible WQIag ( Water Quality Index for Ag. Runoff )

4. Components Field physical /sensitivity factors Nutrient management Tillage management Pest management Irrigation management Conservation practices WQIag ( Water Quality Index for Ag. Runoff )

5. Procedure Multiple factors in a component Ranking and combining factors within a component Ranking and combining different components WQIag based upon 4-key components Adjusting WQIag based upon irrigation type Adjusting WQIag based upon conservation practices WQIag ( Water Quality Index for Ag. Runoff )

6. WQI-Ag Field Physical/Sensitivity Factors (Rainfall /Vegetation Interaction) Vegetative cover Rainfall H*L (9)H*M (8)H*H (7) M*L (6)M*M (5)M*H (4) L*L (3)L*M (2)L*H (1) Rainfall Category Slope Gradients < 2%2-5%5-10%10-15%>15% Low ( L) < 2.50 in < 2.00 in < 1.75 in < 1.50 in < 1.00 in Medium ( M) 2.51 to 7.0 in 2.01 to 6.0 in 1.76 to 5.0 in 1.51 to 4.0 in 2.0 to 3.0 in High ( H) > 7.0 in > 6.0 in> 5.0 in> 4.0 in> 3.0 in Vegetation Category Description Low ( L) Less than 30% vegetative cover (dead or live) Medium ( M) 31 to 80% vegetative cover (dead or live) High ( H) More than 80% vegetative cover (dead or live)

7. WQI-Ag Field Physical/Sensitivity Factors (Rainfall /Vegetation Interaction) JanFebMarAprMayJunJulAugSepOctNovDec Rainfall (in)6.174.393.992.642.171.730.70.941.843.116.027.09 Rainfall Factor HHMMMLLLLMHH Veg CoverLLLMMHHHHMML Veg* Rainfall Factor L*H L*MM*M H*L M*MM*HL*H WQI- fvr112559999541

8. WQIag Field Physical/Sensitivity Factors (Hydrologic Soil Group, K-Factor & %OM Content) Hydrologic Soil Group Slope Gradients < 2%2-5%5-10%10-15%>15% A:Low runoff potential 109754 B: Moderately low runoff potential 108643 C :moderately high runoff potential 97532 D, A/D, B/D, C/Dhigh runoff potential 86421 % OM RangeWQI-om >8%10 6-8%9 4-6% 7 2-4%6 0.5-2%4 <.5%2 Kw factor - surface mineral layer Slope Gradients < 2%2 - 5% 5 - 10% 10 - 15%>15% <=0.10 very low erodibility 10 97 0.11 - 0.20 low erodibility 10 975 0.21 - 0.32 moderate erodibility 98754 0.33 - 0.43 high erodibility 87532 0.44 - 0.64 very high erodibility 86421

9. WQI-fsf Integrating Soil Physical/Sensitivity Factors Soil Sensitivity Component Soil Sensitivity Option WQI Ranking (WR) Weighing Factor (WF) 1 WR*WF Hydrologic Soil Group Group B (moderately low runoff potential) 80.252.0 K-Factor 0.30 (0.21-0.32 moderate erodibility) 80.252.0 OM Content 5% (4-6% range) 70.251.75 Rainfall/ Vegetation Annual Mean Average for the example case 50.251.25 Mean WQI-fs (Total of all four rows)1.007.0 1 The sum total of rows should equal 1

10. WQI-narNutrient Management Component Nutrient Application Rate (WQI-nar) Nutrient Source and Application Timing (WQI-nst) Nutrient Application Method and Soil Condition (WQI-nms)

11. WQI-narFertilizer Application Rate Application RateWQI-nar No Fertilizer Applied10 50% less of the LGU recommendation7.5 40% less of the LGU recommendation7.0 30% less of the LGU recommendation6.5 20% less of the LGU recommendation6.0 10% less of the LGU recommendation5.5 LGU recommendation5.0 10% over the LGU recommendations3.0 20% over the LGU recommendations1.0

12. WQI-ntt Fertilizer Sources and Application Timing Application Type N-Source & Application Timing Synthetic Fertilizers Composted Organics Un- composted Manure Normal Fertilizers Slow Releasing Fertilizers During Growing Season Pre-growing Season Single 86 10 42 Split Application 108NA64 P-Source & Application Method s Single72 NA 42

13. WQI-nms Fertilizer Application Methods/Soil Condition Soil Condition Application Method Anhydrous Ammonia Other forms of N-Fertilizer (Solids or Liquids) Injected Surface Banded Broadcasted & Incorporated Broadcasted Dry/Well Drained 210876 Moist (25% FC in upper 24 in soil depth) 986 5 4 FrozenNA 2

14. WQI-nm Integrating Nutrient Management Factors

15. WQI-tm Tillage Management Tillage DescriptionSTIR ValueWQI-tm No Till< 3010 Mulch Till31 to 607.5 Conventional Till60 to 1005 Intensive Till  100 2

16. WQI-pm Pest Management Description of PracticeWQI-pm Follow IPM with No Chemical Suppression Needed 10 Follow IPM with Suppression using Low Risk Chemicals 7.5 Follow IPM and Suppress using Chemicals and Mitigation 7.0 Suppress with Chemicals and Mitigate 5 Chemical Suppression and No Mitigation 2

17. WQIag Integrating WQIag Components (No Irrigation & No Additional Conservation Practices)

18. WQI-tm Irrigation Management S.N0.Irrigation Method % WQIag Adjustment 1Surface - Wild flood-15% 2Surface - Graded furrow-12.5% 3Surface - Graded border-10% 4Sprinkler-7.5% 5Center Pivot-5% 6Trickle / Drip-2.5% 7 Level basin / blocked end 0% 8No Irrigation (0%)0%

19. WQIag Integrating WQIag Components (Drip/Sprikler Irrigation & No Additional Conservation Practices)

20. WQI-tm Conservation Practices Conservation Practice Effectiveness Range (mean) % WQI Adjust Factor % NameType Contour Strip-croppingField50-60 (55)27.50 Contour Buffer Strip Field20-75 (47.5)23.75 Sediment Basins External75-95 (85)42.5 Field BordersField50-80 (65)37.5 Riparian Forest BufferExternal50-80 (65)37.5 Filter StripExternal50-80 (65)37.5 Grass Waterway External60-80 (70)35.0 Field Strip croppingField75.037.5 Conservation CoverFieldUp to 9035.0 Water & Sediment Control Basin External40-60 (50%)25.0 Tailwater Recovering System External37.5

21. WQIag Conservation Adjustment Factor = Eff Field Level WQI = WQIag For WQIag <= 5.5 (mid-point range of the WQiag between 1 to 10); WQIag with Conservation Practice = WQIag(1+Eff/100) For WQIag > 5.5 WQI with conservation practice = (WQI + ((10-WQIag)*Eff/100)) Adjusting for Conservation Practices

22. WQIag Integrating WQIag Components (Drip/Sprikler Irrigation & No Additional Conservation Practices)

23. Web-based WQIag

24. Concluding Remarks Only an index not a real measurement Influenced by local professional judgment and preferences Highly useful when actual monitoring is out of reach Need to be further tested and verified Sensitivity of different components and factors WQIag ( Water Quality Index for Ag. Fields )

25. Future Work Have regional experts review the heuristic of different components for site-specificity Test and validate the index for multiple Scenarios Extend the index to include farm level conservation practices Develop a framework for using such an index at the small watershed level WQIag ( Water Quality Index for Ag. Fields )

26. Extending WQIag to Farm Level Farm Name Location Weather Fields 1 to N Field 1 Practice Eff. Acres WQI-F1 Farm Practice WQI-FP1 WQI- Params Field 2 Practice Eff. Acres WQI-F2 Farm Practice WQI-FP2 WQI- Params Field 3 Practice Eff. Acres WQI-F3 Farm Practice WQI-FP3 WQI- Params Field N Practice Eff. Acres WQI-FN Farm Practice WQI-FPN WQI- Params WQI FPi = WQIFi (1+Practice Effi) for WQIFi <= 5 WQI FPi = WQIFi+(10-WQIFi)*(1+Practice Effi) for WQIfi > 5 WQIFarm = Sum Total of WQI-FPs of all fields weighted by their respective acreage