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Land Sediment Calibration Final results. Modeling Subcommittee 5/3/05. BMP Factor. Edge of Stream. Land Acre Factor. Delivery Factor. In Stream Concentrations. Sediment Pathway in Phase 5. Edge of Field. Forest Harvested Forest Natural grass Extractive
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Land Sediment Calibration Final results Modeling Subcommittee 5/3/05
BMP Factor Edge of Stream Land Acre Factor Delivery Factor In Stream Concentrations Sediment Pathway in Phase 5 Edge of Field
Forest Harvested Forest Natural grass Extractive Barren Pervious Urban Impervious Urban Pasture Bad Pasture Hay High till with manure High till no manure Low till with manure Total13 land uses for sediment simulation Agriculture Other
Pasture => Pasture Bad Pasture => 9.5 * Pasture Hay => 1/3 Crop (P4 NRI) High till with manure => 1.25 * Crop High till no manure => 1.25 * Crop Low till with manure => 0.75 * Crop Needed EOF targets for 13 land uses Agriculture - NRI gave estimates of Pasture and Cropland for each county
Forest => Use P4 NRI Harvested Forest => Mean Forest * 10 = 3.4 t/ac/yr Natural grass => Mean Pasture = 1.5 t/ac/yr Bare => 40 t/ac/yr Extractive => 10 t/ac/yr Pervious Urban => 0.74 t/ac/yr Impervious Urban => 5.18 t/ac/yr Aeolian => 10 lb/ac/day Needed EOF targets for 13 land uses Other – targets estimated from literature or previous model values
Wash off Generation Attachment Rainfall Detachment Land Sediment Simulation Detached Sediment KSER KRER AFFIX NVSI Soil Matrix (unlimited) 4 parameters, 1 target
Decision Rules for Four Key land Parameters: Rule 1 - Zero Detached Sed after Large Storms vanSickle and Beschta (1983) Allen Gellis (pers communication)
Rule2 – Detached Sediment Storage Reaches 90% of its Max in 30 Days AFFIX = 0.07673
Detached Sediment Generation KRER NVSI Rainfall Detachment Soil Matrix (unlimited) Rule3 – Generation makes up significant portion of Detached Sediment • NVSI = [significant fraction] * target load
Strategy: Reduce the Parameter Set • Assume ratio of NVSI : EOF target • Assume ratio of KSER : KRER • Adjust KSER to meet target • 20 scenarios formulated - Ratio of NVSI : EOF Target picked from { 0.5, 1, 1.5, 2} - Ratio of KSER:KRER picked from { 2, 5, 10, 15, 20}
Strategies to optimize ratios: • Does the simulated EOF meet the target? • Does the model correctly capture the dynamic of land process? • Do the different land calibrations make a difference in the correlation between simulated and observed?
Iterative simulation results • Scenarios with KSER/KRER ratio > 5 could NOT reach the targets for some of segments, particularly for Barren land • Choices narrowed down to 8 scenarios • Optimal scenario should have lower average dets and higher correlation
- Dynamic of land process Land segment A42033 - pasture, KSER/KRER = 5 Detached Storage goes down to zero sometimes
Different scenarios make little difference on the correlation of simulated and observed concentrations Correlation of sediment concentrations for each of 8 scenarios
Average detached storagedecrease withDecrease of NVSI ratio and Increase of KSER/KRER ratio Average detached storage for each of 8 scenarios
Final solution and Status • AFFIX = 0.0765 • NVSI : EOF target = 1.5 • KSER : KRER = 5 • EOF calibration done two weeks ago • Have used for river calibration since