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