2012-07-10_PERMIT FILE - C1981041 (5)

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RECLAIMED AREA - "C" FACTOR Cameo Refuse Disposal Area #1 No appreciable canopy. Canopy is assumed to be the combined cover contributed by trees and shrubs. Based on the 2010 Vegetation Evaluation the combined tree and shrub cover totals 9.5 %. The percent ground cover for the reclaimed area shown on the preceding page is 60.5 %. Use figure 7 identified above and interpolate to determine the C factor for 60.5% cover. CANOPY NO APPRECIABLE CANOPY PERCENT GROUND COVER 60.0% 60.5% 80.00/0 No G 0.042 0.041 0.013 appreciable Adacent "C" Factor 0.041 canopy USING THE UNIVERSAL SOIL LOSS EQUATION A= RKLSCP A is the sal loss in Tons/Acre/Year Shadscale Reference Adjacent CRDA#1 Reclaimed R = rainfall factor 20.00 20.00 K = soil erodibil' factor - Torriorthents 0.37 0.37 LS = combined length slope factor 15.87 10.353 C = cropping management factor: "C" - Crop Management - Shadscale Canopy 2.7% Cover - Grass 4.1% Ground Cover 44.9% 0.08579 "C"- Crop Management - CRDA#1 Canopy 9.5% Cover - Grass 10.7% Ground Cover 60.5% 0.04129 P = erosion control pracUce factor 1.00 1.00 SOIL LOSS CALCULATION AREA R K I LS C P A Shadscale Reference Area - Adjacent 20 0.37 1 15.87 0.086 1.0---T 10.07 Cameo Refuse Disposal Area #1 - Reclaimed 20 1 0.37 1 10.353 0.0413 1.0 3.16 It can be seen from the above calculation that the revegetated area of the Cameo Refuse Disposal Area #1 may lose about 3.16 tons per acre per year to erosion. The Shadscale Reference Area which represents the baseline conditions may lose about 10.07 tons per acre year to erosion. The above calculation demonstrates that untreated drainage from the reclaimed area will contribute fewer suspended solids to streamflow or runoff outside the permit area than untreated drainage from the natural surrounding premining area. Pond 6 receives drainage from the Cameo Refuse Disposal Area #1. Based on this demonstration Pond 6 can be reclaimed. Pond 6 has never discharged, therefore, no quality analysis has been performed on the runoff to or from this pond. The disturbed area will not contribute additional suspended solids above natural conditions, and the quality of untreated drainage from the disturbed area will meet the State and Federal water quality standard requirements applicable after the sedimentation pond and treatment facilities are removed because the surrounding areas are very well vegetated and there is virtually no erosion or other stability issues. It is unlikely any significant runoff from the well vegetated reclaimed areas will reach the Colorado River. The calculated runoff from the reclaimed areas for the 10 year storm (1.4 ") event is 0.68 AF for Pond 6 (Appendix 13-2). The runoff from this area is insignificant when compared to the average annual runoff generated from the entire Colorado River drainage (2.8 million AF per year). PR-5 A14-13 -3 02/12