2012-11-05_REVISION - C1982056 (5)

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Coarse fragments dissipate the kinetic energy associated with raindrop impact and hence, decrease particle detachment. The coarse fragments not only reduce raindrop splash erosion, but also retard surface runoff. Spoil pores have a tendency to remain open longer than finer textured materials that may become puddled and swell shut. The greater permeability of the spoils increases the infiltration rate, thereby, decreasing erosion potential. Disturbed areas will remain in a rough condition until final grading is required for seedbed preparation. Leaving the graded surface in a roughened configuration enhances stability and improves moisture penetration. Final grading will be conducted along the contour in a manner that is consistent with the surface water drainage system. Manipulation of the spoils will be avoided when excessively wet conditions exist, in order to minimize compaction. However, frost action plus wetting and drying should loosen most compacted zones to a depth of 20 inches, as documented by Shafer et. al., (1979). Prior to seeding, the spoils will be chisel - plowed in order to alleviate compaction and promote water infiltration. Chisel - plowing has been a highly effective means of temporary stabilization prior to vegetation establishment. Dollhopf, et. al., (1977), reported that chisel - plowing topsoil at the Savage, Beulah and Colstrip surface mines was only surpassed by the radical treatment of dozer basins in reducing overland water flow from reclaimed mine sites. The water detention capacity of chisel - plowed areas is reported by Dollhopf, et. al., (1977), as 176,400 liters per hectare, or 2,521.3 cubic feet per acre. Another stabilization technique which serves to minimize erosion is contour furrowing. Disturbed land within the proposed permit area will be contour furrowed following seeding. A typical cross section 2.05 -35