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LS (length and percent slope factors account for the length and percent slope. These <br />factors are taken from Table 1. Length of slope begins at the top of the micro <br />watershed. This is usually at the top of a hill, ridge, terrace or diversion. The length of <br />slope is considered to end for a given field at one of the following places: (1) the point <br />where the slope decreases to the extent that deposition occurs, (2) the point where <br />runoff enters awell-defined channel, gully, terrace or diversion , or (3) where water <br />leaves the field. The LS for the natural and reclaimed slope was measured from the <br />top of the slope, EI. = 7300' to the bottom of the slope, EI.=7075. The LS factor for the <br />natural and reclaimed slope were developed immediately adjacent to each other and <br />are therefore equal. <br />C (cropping - management) factors are the ratios of soil losses from lands cropped <br />under specified conditions to the corresponding losses from tilled, continuos fallow. C <br />factors for land uses other than cropland are included on Figures 7,8, and 9. The <br />percent ground cover is the primary item to consider because a slight change in <br />the percent ground cover will result in a significant change in the erosion <br />prediction. The natural "C" factor is derived from Figure 7 and the reclaimed "C" factor <br />is based on manufacturer's recommendations. <br />P (erosion control practices) factors are support practices which slow runoff water and <br />thus reduce the amount of soil it can carry. The P factor is the ratio of soil loss with the <br />supporting practice to that of soil loss with up-and-down hill culture. The P factor is the <br />same for the natural and reclaimed slope. <br />All factors in the USLE equation, except the C-factor, are constant relative to the pre- <br />mining (adjacent, natural area) and post mining (reclaimed slope) conditions. <br />Therefore, vegetative condition is the key variable in making a determination that the <br />potential sediment yield is less after mining than before mining. The natural "C" factor <br />for the USLE is calculated from Figure 7, from agronomy note #50, January 1977. <br />NATURAL - "C" FACTOR <br />Appreciable canopy. Canopy is assumed to be the combined cover contributed by <br />trees and shrubs. Based on the Bowie No.1 Mine 1986 vegetation inventory, the <br />combined tree and shrub cover totals 30.1 %. The percent above ground cover for the <br />natural area is 90.1 %. Use Figure 7 identified above and interpolate to determine the <br />"C" Factor for 90.1 % cover and 30.1 % canopy. <br />SAE - 34 5/Ol <br />