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Length-Slone Factor ( L.S). The length-slope is described es the typical length-slope for <br />• the subwetershed and i <br />the di <br />t <br />f <br />th <br />t <br />f <br />i <br />i <br />f <br />l <br />d fl <br />til th <br /> s <br />ance <br />rom <br />e po <br />n <br />o <br />or <br />n o <br />over <br />an <br />g ow un <br />e <br /> point that the slope decreases such that significant deposition occurs or until the flow <br /> enters a defined channel. The length-slope for Pond 009 was determined to be 300 feet, <br /> and the average slope was determined to be 37 percent. Following is McKOOI et al's. <br /> (1987) L,S equation: <br /> m <br />L,S = ( L ) • (17.2 <br />sin - 0.55) for S >8X <br /> 72.6 <br /> 0~6 <br /> L,S = ( 300 ) • (17.2 sin 20.4° - 0.55) <br /> 72.6 <br />L,S = 2.34 • (5.995 - 0.55) <br />L,S = 12.7 <br />The C end P Factors. The C factor, the cover end management factor, is the ratio of soil <br />loss from an area with specified Lover end management to that from an identical area in <br />tilled continuous fallout. <br />• The P factor, the support practice factor, is the ratio of soil loss with a support <br />practice like contouring, strip cropping, or terracing to that with straight-row farming <br />up end down the slope. <br />The C factor was determined based on the vegetation description in Tab 10 end with the aid <br />of the USDA-ARS revised USLE software program for each cover type within the overall <br />drainage area. The P factor is based on current or future practice. Table 13-SA-5 shows <br />the weighted average results for the C and P factors for the various areas. <br />TABLE 13-SA-5 <br />Weighted CP Factor <br />Pond 009 Watershed <br />r <br />Vegetation Tvoe CP Area (ac J CP x Area <br />Aspen 0.001 34.58 0.0346 <br />Mined Brush 0.003 34.74 0.1042 <br />Sagebrush 0.003 67.21 0.2016 <br />• <br />Meadow 0.001 0.55 0.0006 <br />13-SA-7 Revised 08/17/92 <br />