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faeuary?000 Cypnu Tu~eetymilr "PondG Era/uslion 4 <br />3.3 Length-Slope Factor, LS <br />• Input parameters to deterrnine the LS factor were obtained from scaled maps of the wateahed 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 \Varner, 1987): <br />TABLE 1.3 <br />CONTROL FACTOR <br />Cover Cover T e Ve etation Control Factor <br />Reclaimed Reclaimed Seed Good (>70%) Cover 0.01 <br /> Mix <br />Dismrbed <br /> <br />Coa]/Refuse None None ].0 <br />Disturbed 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 include, <br />but are not limited to, terrace construction, roughening of surface, and/or contour furrows. The <br />values utilized are shown in Table 1.4, Practice Factor (Renard e! n!, 199G1(Schwab and Warner. 19871: <br />TABLE 1.4 <br />PRACTICE FACTOR <br />Surface Surface T e Practice Practice Factor <br />Reclaimed Regraded <br />Reclaimed Furrow 0.5 <br />Spoils (Pre-Law) Spoils, <br />Paztial 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 m[o the SEDCAD4 computer model. The distribution <br />was obtained Erom previous analyses performed for [he TCC mine and is shown on the SEDCAD4 <br />prinrouts. <br />4.0 POND G SUMMARY <br />• The modeLng of Pond G predicts that ¢ will effectiveh~ treat the runoff produced from the 10-}'ear, <br />24-hour storm event and safe!}' pass the peak flow Erom the 100-}'ear, 24-hour storm with a tnitumum <br />1.0 foot of freeboard. The inpu[ parameters and results are shown on the SEDCAD4 printouts and <br />summarized in Table ].5, Pond G Summary. <br />Montgomery ~Cratson hfining Group • 1G5 S. Urtion Boulevard, Suite 410' Lakewood, Colorado 80228' (303) 7G3 5140 <br />