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APPENDIX Z <br />~ SOIL LOSS EQUATION STUDY <br />PREDICTED EROSION FROM UPPER BASIN DIVERSION CHANNEL: <br />ORCHARD VALLEY MINE " <br />by <br />C. F. LEAF, P.E. <br />INTRODUCTION <br />The modified Universal Soil Loss Equation (LISLE) recently developed <br />by Utah State University was used to estimate potential erosion from three (3) <br />alternative locations for the upper basin diversion channel at Orchard Valley <br />Mine. The procedure has been discussed in some detail by Leaf (1978).1 <br />~1 <br />• <br />RESULTS <br />Table 1 summarizes the results from this analysis. The parameters <br />listed in Table 1 have been defined in Leaf (1978). Of the three alternatives <br />evaluated, No. III will contribute the least amount of sediment. It will <br />result in a shorter channel with less area disturbed. In addition, it is <br />located on the upper bench, where considerable disturbance has already taken <br />place. The reduced visual impact of this channel is obvious considering that <br />4 acres are disturbed under Alternative III as compared to almost 37 acres <br />under Alternative I. <br />The analysis is considered to be conservative since the erosion <br />control factor (VM) was assumed to be 1 under Alternative II and I1I. Reclama- <br />tion of the cut slopes should considerably reduce soil loss. VM was assumed <br />`Leaf, Charles F. <br />. ' 1978. Environmental Hydrology, Colorado Westmoreland lnc., Orchard Valley <br />t•tine, Paonia, Colorado: Supplement II - Appendix I report submitted to <br />• 4estmoreland Coai Company. <br />