2016-01-22_REVISION - C1981014 (4)

Home Browse Search

Sediment Demonstration — Mine Site - revised 1/22/2016 w/ 1/8/2016 addendum Page 4 Section 3.03.1 Mean Cover Reference Areas (non -mined condition) 2013 2014 Mean Plant and litter cover RDA reference area 70.27 75.33 72.8 Portal reference area 73.82 67.73 70.78 Old Portal Refer. area 63.52 83.9 73.71 Height Two year mean 72.43 Mean Cover Reclaimed Areas (reclaimed condition) 2013 2014 Mean Plant and litter cover Corley reclamation 65.47 77.34 71.40 Vento reclamation 75.8 75.47 75.63 RDA reclamation 80.08 82.2 81.14 Height Two year mean 1 76.60 Table 1 C Factors Area % Canopy and Type % C Height Ground Factor Cover Facility and RDA (reference area) 25% G 72.43% .0218 Facility and RDA (reclaimed area) 25% G 76.60% .017 Support Practice Factor (P) The P factor represents the ratio of soil loss from any conservation practice to that with upslope and downslope tillage. It is used to evaluate the effects of contour tillage, strip -cropping, terracing, subsurface drainage, and dryland farm surface roughening. While a cover crop and seeding practices on the reclaimed area may have roughened the soil initially in the revegetation liability period, there is no support for any remaining effects of these conservation practices as compared to the non -mined reference area. For reclaimed and non -mined conditions a P factor of 1.0 was used. RESULTS The above input parameters were substituted into the RUSLE equation for both the reclaimed and non - mined condition. As shown below in Table 2, sediment yield for the reclaimed condition is slightly less than the non -mined condition for the Southfield Mine site and RDA. Non -mined condition A=RKLSCP A = (24.7)(.32)(3.755)(.0218)(1.0) A = .648 Reclaimed condition A=RKLSCP