2015-09-17_PERMIT FILE - C1984065A (2)

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• • RECLAIMED AREA -'C' FACTOR Portal Area and Benches No appreciable canopy. Canopy is assumed to be the cover contributed by trees and shrubs. Based on the 2000 vegetation study the combined tree and shrub cover totals 2.6%. The percent ground cover for the reclaimed area shown on the preceding page is 83.9%. Use figure 7 identified above and interpolate to determine the C factor for 83.9% cover. NO APPRECIABLE CANOPY CANOPY PERCENT GROUND COVER 80.0 83.9 100.0 0% G 0.013 0.011 0.003 2.6% Hecialmedac or 0.077 25%/0 0.003 USING THE UNIVERSAL SOIL LOSS EQUATION A=RKLSCP A is the soil loss in Tons/Acre/Year Baseline Reclaimed Relcaimed Reference Portals Benches R = rainfall factor 30.00 30.00 30.000 K = soil erodibility factor - Nihill channery loam 0.24 0.24 0.240 LS = combined length slope factor Portal & Reference 300' Slope 29%% Grade 13.20 13.20 Benches 340' Slope 14%% Grade 4.200 C = cropping management factor: 'C' - Crop Management - Baseline Canopy 26.5% Cover - Grass 22.5°/% Ground Cover 83.1°/% 0.011 'C' - Crop Management - Reclaimed Canopy 2.6% Cover - Grass 23.5% Ground Cover 83.9°/% 0.011 0.011 P = erosion control practice factor 1.00 1.00 1.000 Soil Loss AREA R K LS C P A Baseline 30 0.24 1 1 Reference Area Reclaimed 3 .011 1.0 1.01 Portal Reclaimed4.2 0.0111.0 0.32 Benches It can be seen from the above calculation that the portal area of the reclaimed mine site and the benches may loose about 1.01 tons and 0.32 tons per acre per year to erosion respectively. The baseline conditions may loose about 1.01 tons per acre per year to erosion. The above calculation demonstrates that untreated drainage from the reclaimed area will contribute the same amount or fewer suspended solids to streamflow or runoff outside the permit area as untreated drainage from the natural surrounding premining area. 4-58iv 06/01