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TR -62 <br />The Universal Soil Loss Equation will be used to calculate the soil loss from the reclaimed mine site, <br />and the adjacent baseline area to determine if untreated drainage from the reclaimed mine site <br />is contributing suspended solids in excess of premining levels. The following <br />sediment volume calculation is prepared in accordance with U. S. Department of Agriculture, Technical <br />Notes, Agronomy Note #50, dated January, 1977. The maps and figures utilized in the LISLE calculations <br />are obtained from the referenced Agronomy Note #50. <br />USING THE UNIVERSAL SOIL LOSS EQUATION <br />R (rainfall) factors are assigned by geographical regions based on weather data furnished by the U.S. <br />Weather Service R values are based on rainfall amount, time, and intensity. In the mountains, R values <br />were computed primarily for valley areas and have been increased to account for run-off from snow melt. <br />The R factor of 30 used for this calculation is derived from an iso-erodent map, presented in the referenced <br />Agronomy Note #50, and is the same for both the reclaimed slopes and the adjacent natural slope. <br />K (soil erodibility) factors are assigned to each soil series and they are used to predict the erodibility of a <br />soil and its tolerance to erosion in relation to specific kinds of land use and treatment. Soils having the <br />highest K value are the most erodible. The K value used for this calculation is picked from the U.S. <br />Department of Agriculture Soil Survey, Paonia Area, and is based on the soils classification <br />of 20 -Cerro stony loam, for the East Mine area, K = 0.17 <br />LS (length and percent slope) factors account for the length and percent slope. These factors are taken <br />from page 6 of this document. Length of slope begins at the top of the micro watershed. This is usually at <br />the top of a hill, ridge, terrace or diversion. The length of slope is considered to end for a given field at one <br />of the following places: (1) the point where the slope decreases to the extent that deposition occurs, (2) <br />the point where runoff enters a well-defined channel, terrace or diversion, or (3) where water leaves the field. <br />The LS for the Adjacent and East Mine Areas are defined by the length and slope gradient within the <br />distuubed area. LS factors for the adjacent areas were developed in the area immediately adjacent to the <br />disturbed area boundary for the east mine areas. The area at the east mine has been broken into two <br />areas, the Fan & Portal bench areas have been grouped together due to steepness and will be evaluated <br />separately (Upper) The remaining reclaimed areas are not as steep and will be analyzed as a separate <br />area (Lower). <br />Pinyon Juniper Adjacent Area (Upper) - LS Factor <br />The LS factor for the Pinyon Juniper Adjacent area is based on an average 2.7HAV Slope and an average <br />vertical height of 110 feet and average length of slope is 250 feet based on the flow lines located in the <br />adjacent area. The length of slope of run-off from the reference area was increased to a length of 255 feet <br />to make it comparable to the east mine area. <br />Average Length 255.0 Feet <br />Average Slope 45.0% <br />Percent Slope (S) <br />40.0% 45.0% 50.0% <br />200 18.000 21.500 25.000 <br />255.0 "LS" Factor 24.25011 <br />300 22.000 26.500 31.000 <br />East Mine reclaimed (Upper) - LS Factor <br />The LS factor for the East Mine Area is based on an average 2.5H:1 V slope at an average <br />vertical height of 107 feet and an average length of slope of 255 based on seven flow lines cut <br />through the reclaimed area. <br />Average Length 255.0 Feet <br />Average Slope 42.0% <br />Percent Slope (S) <br />40.0% 42.0% 45.0% <br />200 18.000 20.800 25.000 <br />255.0 "LS" Factor23.440 <br />300 22.000 25.600 31.000 <br />Volume 8A - 9 <br />10/16 <br />