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funnaq~_000 C}p.,r, Tmenrymde"PouAB Eualaaliou 4 <br />3.3 Length-Slope Factor, LS <br />• Input parameters [o de[ermine the LS factor were obtained from scaled maps of the watershed areas. <br />Values measured from the scaled maps are shown on the attached SEDCAD4 results. <br />3.4 Control Factor, C <br />The control Factor is used to account for vegetative or mulch cover. Reclaimed area cover percentage <br />obtained from Colorado Yampa Coal, 1999. The values utilized are shown on Table 1.3, Control <br />Factor (Schwab and \Vamer, 1987): <br />TABLE 1.3 <br />CONTROL FACTOR <br />Cover CoverT a Ve elation Control Factor <br />Reclavned Reclaimed Seed Good (>70%) Cover 0.01 <br /> Mix <br />Disturbed <br /> None None 1.0 <br />Coal/Refuse <br />Dlsturbed None NA 1.0 <br />3.5 Practice Factor, P <br />• The practice factor is used to account for conservation practices for the watershed. These may uxlude, <br />but are not limited to, terrace constmction, roughening of surface, and/or contour Furrows. The <br />values utilized are shown in Table 1.4. Practice Factor (Renard e! a/ 199G1(Schwab and \L''arner- 1987): <br />TABLE 1.4 <br />PRACTICE FACTOR <br />SttrCace Surface T e Practice Practice Factor <br />Reclaimed Regraded <br />Reclaimed Furrow 0.5 <br />Spoils (Pre-Law) Spoils, <br />Partial Grading Rough and Irregular 0.8 <br />Coal Stockpiles Coarse Material Rough and Irregular 0.8 <br />Disturbed Stripped None 1.0 <br />3.6 Sediment Particle Distribution <br />A sediment particle size distribution was input into the SEDCAD4 computer model. The dismbuuon <br />was obtained from previous anal}'ses performed for the TCC mine and is shown on the SEDCAD4 <br />printouts. <br />4.0 POND B SUMMARY <br />. The modeling of Pond B predicts [ha[ it will effectively treat the mnoff produced from the 10-yeas, 24- <br />hour storm event and safely pass the peak tlow from the 25-year, 24-hour storm with a rmrtimum 1.0 <br />foot of freeboard. The input parameters and results are shown on the SEDCAD4 printouts and <br />summarized in Table 1.5, Pond B Summary. <br />Montgomery 1\rarson ~Lning Group ' 1G5 S. Union Boulevard, Suite 41D' Lakeurood, Colorado SD228 " (3D3) 7G3-SIiD <br />