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lines drawn for each area, and the average values for the L and percent slope were <br />used. Using Technical Note #50, Figure 4, the "LS" figure was determined. <br />"C" Factors have been selected using the SedCad menu for Permanent Pasture and <br />Rangeland for the current, reclaimed configuration. Percent cover was estimated using <br />Google earth and professional judgment. <br />"C" factors for the reference areas, or the pre -mining condition were selected from <br />Exhibit 15, Table 10. <br />Subpart H Discussion: <br />The CDPHE discharge permit requires a comparison of average annual sediment yield <br />between pre -mining conditions and reclaimed conditions. Two different methods are <br />used for this analysis. The first is based on monthly data collected from the Discharge <br />Monitoring Reports. This data will compare only the sediment suspended during a <br />specific pond discharge event, but it is actual data and will be compared to the SedCad <br />calculated data. The second method of evaluation will utilize a the Revised Universal <br />Soil Loss Equation (RUSLE) to compare the annual sediment loss between the two <br />conditions. <br />The CDPHE discharge permit requires monthly monitoring of Total Suspended Solids <br />(TSS). Over the last seven years the ponds have discharged a total of eight (8) times. <br />In an effort to be conservative, the values shown for the TSS are in excess of the <br />permitted value, and the maximum recorded value for the seven year term. The TSS <br />data obtained when the ponds have discharged is shown below. <br />SedCad calculated values for the pre -mining condition follow this report. <br />Results from the demonstration are summarized below. <br />------------------------- ---------=------------------=-------------------------- <br />Outfall/SedimentLoss <br />-4-------- <br />Pond <br />12 <br />Sediment <br />--------------------------------------------- <br />Pre -Mining <br />TSS <br />DMRs <br />--------------------------- <br />mg/I ------ ---------- <br />mg/l----------- <br />00510,043.00 <br />---------------------------------- <br />--------------------------------------------- <br />70 <br />006a6,129.00 <br />-------------------------'---------'------------------------------------------- <br />37 <br />007a --------- <br />10,854.00 <br />No Discharge <br />008 <br />7,246.00 <br />69 <br />009 (Outfall 030) <br />9,625.00 <br />237 <br />009a <br />- ------------------ - <br />--------------------------------------------------------------------------------- <br />..... _____No- <br />Discharge_____ <br />Column_ 1- SedCad-calculated - <br />edCadcalculated_ TSS_ value, pre -mining ........................ <br />Column 2_- Actual discharge <br />data as reported in DMRs <br />-------------------------- <br />from 2008-2015 <br />* Values listed are acute exceedences, permitted value is 45m /1 <br />Subpart H Demonstration Page 2 03/15 <br />