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"LS" factors were developed using Google Earth for the current configuration, <br />and a topo map for the pre -mining condition. For each configuration, a line was <br />drawn on the slope and therefore the "L" was determined. Next, the difference in <br />elevation between the beginning and end point of the line was determined. By <br />dividing the change in elevation by the length of slope, the "S" or percent slope <br />was determined. There were multiple lines drawn for each area, and the average <br />values for the L and percent slope were used. Using Technical Note #50, Figure <br />4, the "LS" figure was determined. <br />"C" Factors have been selected using the SedCad menu for Permanent Pasture <br />and Rangeland for the current, reclaimed configuration. Percent cover was <br />estimated using Google earth and professional judgment. <br />"C" factors for the reference areas, or the pre -mining condition were selected <br />from Exhibit 15, Table 10. The "C" Factor for the Oak/Pinyon reference area was <br />revised under MR -14 to more accurately represent the description of the land <br />use. Previously, it was assumed that the area for Oak/Pinyon was a grazed <br />woodland (forest). But since there is only 0.3% trees in the reference area, it is <br />more reasonable to assume the land use is rangeland consisting of mostly <br />grasses and shrubs. The Description in the table as well as the CP factor have <br />been revised. <br />Subpart H Discussion: <br />The CDPHE discharge permit requires a comparison of average annual sediment <br />yield between pre -mining conditions and reclaimed conditions. Two different <br />methods are used for this analysis. The first is based on monthly data collected <br />from the Discharge Monitoring Reports. This data will compare only the <br />sediment suspended during a specific pond discharge event, but it is actual data <br />and will be compared to the SedCad calculated data. The second method of <br />evaluation will utilize a the Revised Universal Soil Loss Equation (RUSLE) to <br />compare the annual sediment loss between the two conditions. <br />The CDPHE discharge permit requires monthly monitoring of Total Suspended <br />Solids (TSS). Over the last seven years the ponds have discharged a total of <br />eight (8) times. In an effort to be conservative, the values shown for the TSS are <br />in excess of the permitted value, and the maximum recorded value for the seven <br />year term. The TSS data obtained when the ponds have discharged is shown <br />below. <br />SedCad calculated values for the pre -mining condition follow this report. <br />Results from the demonstration are summarized below. <br />Subpart H Demonstration Page 2 03/15 <br />