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It can be seen from the above calculation that the revegetated areas at Pond 7 and Pond <br />9 may loose about 0.92 and 0.27 tons per acre per year, respectively, to erosion. The <br />Pond 7 and Pond 9 adjacent areas, which represent the baseline conditions, may lose <br />0.98 and 0.37 tons per acre per year. Based on this demonstration, the reclaimed areas <br />are not contributing suspended solids in excess of pre -mining levels. <br />CRDA 1 Road <br />SOIL LOSS CALCULATION <br />AREA <br />R <br />K <br />LS <br />C <br />P <br />A <br />Adjacent Area-CRDA Road #1 <br />30 <br />0.24 <br />7.14 <br />0.192 <br />1.0 <br />9.88 <br />CRDA Road #1 <br />30 <br />0.24 <br />1.560 <br />0.191 <br />1.0 <br />2.15 <br />It can be seen from the above calculation that the revegetated area at the CRDA Road <br />#1 may loose about 2.15 tons per acre per year, to erosion. The CRDA Road #1, which <br />represent the baseline condition, may lose 9.88 tons per acre per year. Based on this <br />demonstration, the reclaimed areas are not contributing suspended solids in excess of <br />re -mining levels. <br />Conclusions: <br />The seven reclaimed and revegetated areas are not contributing suspended solids in <br />excess of the pre -mining levels. Additionally, untreated drainage from the disturbed <br />areas is required to meet the State and Federal water quality standard requirements <br />applicable after the sedimentation ponds and treatment facilities are removed. Run-off <br />from the reclaimed areas ultimately flow into the Colorado River with no notable <br />negative impacts to water quality. <br />The seven reclaimed ponds and borrow areas encompass a total of 0.02 square miles <br />and runoff from those areas will flow into the Colorado River. The total drainage basin <br />of the Colorado River is 240,000 square miles. The reclaimed areas account for <br />.000008% of the total Colorado River Drainage basin. <br />The very small drainage area of the seven reclaimed areas would not have any <br />measurable impact on the quality or quantity of water in the Colorado River. The <br />vegetation on site will help reduce the sediment load that enters the Colorado River. <br />The soils on site do not have any physical or chemical constituents that would degrade <br />water quality. There is no reason to believe oil and grease will contaminate runoff from <br />the reclaimed areas since there is no oil or grease storage areas within the reclaimed <br />areas. <br />SL -9 Tab -9, Page 4 Revised 10/18/2016 <br />