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Page 3 <br />Section 3.03.1 <br />hillslope length and steepness increase, under the assumption that runoff accumulates <br />and <br />accelerates in the downslope direction. This assumption is usually valid for lands <br />experiencing overland flow but may not be valid for forest and other densely-vegetated <br />areas. <br />The C factor is an expression of the effects of surface covers and roughness, soil <br />biomass, and soil-disturbing activities on rates of soil loss at a particular site. The value <br />of <br />"C" decreases as surface cover and soil biomass increase, thus protecting the soil from <br />rain splash and runoff. <br />The P factor is an expression of the effects of supporting conservation practices, <br />such as contouring, buffer strips of close-growing vegetation, and terracing, on soil loss <br />at a <br />particular site. The value of "P" decreases with the installation of these practices <br />because <br />they reduce runoff volume and velocity and encourage the deposition of sediment on <br />the <br />hillslope surface. The effectiveness of certain erosion-control practices varies <br />substantially <br />due to local conditions. For example, contouring is far more effective in low-rainfall <br />areas <br />than in high-rainfall areas. <br />Surety Release No. 1 (SL-01) does not document that the applicant submitted a Phase <br />II sediment demonstration nor do the Division's findings make any reference to a finding <br />with regard to sediment production. <br />Section 11.4 of the written findings for Surety Release No. 3 (SL-03) documents the <br />methodology used and approved by the Division. Colowyo used four study blocks to <br />calculate gross sediment yields from pre-mining and reclaimed lands. Colowyo used <br />documented K values for pre-mining soils and blended K value for post-mining soils due <br />to mixing. LS factors represented the pre-mining and post-mining slopes. C factors <br />were selected based on year 2000 sampling results for the reference area for the pre- <br />mining condition, and year 2000 sampling for the reclaimed study blocks for the post- <br />mining condition. The Division considers this methodology and these parameter input <br />assumptions valid to estimate pre-mining and post-mining sediment production for <br />comparison purposes. <br />Review of Results. SL-04, Sediment Demonstration <br />Section 4.0 of the application discusses and calculates the estimates regarding pre- <br />mining and post-mining sediment production. Again, as in past Phase 11 sediment