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Where lands are disturbed or geomorphic thresholds are surpased however, ero- <br />• sional processes may be accelerated and become detrimental to land use and <br />receiving drainages. These effects are not always man caused and in fact, data <br />show that the United Slates entered a period of very rapid erosion prior to its <br />settlement as a result of a change in the amount and frequency of precipitation <br />(Dory, 1966). <br />It is unavoidable that mining will temporarily increase erosion potential. The <br />texture of the soils, the long slopes and spring snownelt on the northern aspecC <br />where the proposed mine plan area occurs all contribute to the erosion potential <br />at Trapper Mine. With proper recon[ouring as described in Sections 3.5.3 and <br />revegetation as discussed in Section 3.6, this potential can be reduced to its <br />premine level or less. Interim erosion control will be necessary to avoid short <br />term impacts to receiving waters and to help stab iiize replaced topsoil while <br />vegetation is establishing. <br />Re topsoiled areas are the most important sites to control erosion. Retention of <br />soil on site is critical since erosion removes seeds and costly topsoil and <br />• results in reclamation failures, clogging of culverts, and filling of sediment <br />ponds. Long term erosion control will be obtained only from a stable vegetative <br />cover: therefore, all initial erosion control measures must be designed with this <br />goal in mined. <br />Many erosion control practices are available for slopes. These include terraces <br />of various types, furrows, [tenches, diversions, erosion cloth or mulch treat- <br />ments and land imprinting. The success of each type of treatment will depend <br />upon the site specific problems and processes at each area. In general, erosion <br />occurs when the soils cannot accepC water as fast as it is received. Therefore, <br />increasing infiltration and reducing runoff is one way of decreasing erosion <br />potential. <br />Several factors influence the erosional process including time, d ra~inage charac- <br />teristics, geology, climate, vegetation and hydrology (Schumm, 1976). Land use <br />is another factor that may significantly affect the erosional process and that <br /> <br />3-56 <br />REVISED fr6 13 '87 <br />