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USING THE UNIVERSAL SOIL LOSS EQUATION <br />IB:�:t�•Y�lr <br />A is the soil loss in Tons/AcreNear <br />R = rainfall factor <br />40 <br />_ <br />K = soil erodibility factor -Loams <br />A <br />Adjacent A_r_ea - Mesic Mountain Shrub <br />0.28 <br />LS = combined length slope factor <br />40 0.28 2.0 <br />0.052 1.0 <br />2.0 <br />Adjacent Area - Xeric Mountain Shrub <br />40 0.28 2.0 <br />C = cropping management factor: <br />1.76 <br />Adjacent Area - Aspen <br />40 0.28 2.0 <br />Factor <br />1.17 <br />Re_c_laimed Drill Pads and Roads <br />"C" - Crop Management - Mesic Mountain Shrub Adjacent <br />0.052 <br />Canopy 44.6% <br />_ <br />Ground Cover 51.8% <br />"C" - Crop Management -_Xeric Mountain Shrub Adjacent <br />0.079 <br />Canopy 54.10/611 <br />Ground Cover 35.8% <br />"C" - Crop Management -Aspen Adjacent <br />0.052 <br />Canopy <br />45.3%1 - <br />- <br />Ground Cover <br />51.3°/x' <br />"C" - Crop Management - Drill Pads and Roads _ <br />Canopy 1 1.30/6 <br />Ground Cover 84.3% <br />0 011 <br />P = erosion control practice factor 1.0 <br />ILL SS CALCULATION <br />R K LS <br />C P <br />A <br />Adjacent A_r_ea - Mesic Mountain Shrub <br />40 0.28 2.0 <br />0.052 1.0 <br />1.15 <br />Adjacent Area - Xeric Mountain Shrub <br />40 0.28 2.0 <br />0.079 1.0 <br />1.76 <br />Adjacent Area - Aspen <br />40 0.28 2.0 <br />0.052 1.0 <br />1.17 <br />Re_c_laimed Drill Pads and Roads <br />j 40 0.28 2.0 <br />0.011 1.0 0.24 <br />It can be seen from the above calculation that the revegetated drill roads and drill pad may lose <br />about 0 24 tons per acre per year. The adjacent Mountain shrub, Xeric mountain shrub and <br />Aspen may lose about 1. 15, 1.76 and 1.17 tons per acre per year respectively. <br />The above calculation demonstrates that untreated drainage from the reclaimed drill pads and roads <br />will contribute fewer suspended solids to stream flow or runoff outside the permit area than <br />untreated drainage from the natural surrounding adjacent areas. Based on this demonstration the <br />alternative sedimentation control devices can be remove from selected drill sites. <br />Additionally, untreated drainage from the reclaimed areas are required to meet the State and <br />Federal water quality standard requirements after the alternative sedimentation control devices are <br />removed from the drill sites. The drill sites have 87.2% perennial cover, rock and litter which leaves <br />an insignificant area on the drill sites that would be subject to erosion. Hubbard Creek and Terror <br />Creek are the two main drainages that receive run-off from the drill sites. Hubbard Creek and Terror <br />Creek have drainage areas of 57.9 and 29.4 square miles respectively according their USGS gage <br />stations. The above calculations demonstrate select drill sites no longer required sedimentation <br />control. A total of 40.1 acres of drill sites are in this category. Nearly all of the drill sites lie in the <br />Hubbard Creek drainage area. The Hubbard Creek drainage area encompasses 57.9 square miles. <br />The 40.1 acres of drill sites represent 0.11 percent of the total drainage area. The acreage of the dril <br />sites is insignificant compared to the drainage area of the creek. Any run-off from the drill sites that <br />reached the creek would not have any impact of the water quality in the creek. <br />Volume 1116, Tab 24 Page 4 <br />TR -101 04/15 <br />