2012-02-27_REVISION - C1981010 (10)

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roughness. To the extent practicable, all farming operations associated with reclamation activities are performed along the contour. Specifically, seedbed preparation and seeding activities are intentionally conducted along the contour. The seeding process itself incorporates a tillage practice which results in a roughened soil surface exhibiting a series of furrows oriented perpendicular to the slope. These practices result in a roughened surface on the reclamation particularly as compared to undisturbed areas. In addition, the documented higher effective cover values established on reclamation also act to roughen the reclaimed surface by necessitating more tortuous flow paths. As a further consideration, Trapper's reclamation procedures routinely include the use of contour ditches and small depressions (i.e. livestock water tanks) to enhance slope stability and reduce erosion. Contour ditches are typically removed after vegetation has become well established, however, the livestock water tanks, which are typically situated in drainages, remain as permanent features. The contour ditches act to shorten overland flow lengths and rill erosion flow paths while vegetation is becoming established and thereby serve to protect the integrity of the initially roughened reclaimed surface until vegetation is established. In all instances, the SEDCAD 4 models demonstrate the total sediment generated from the reclaimed blocks is less than or approximately equal to the total sediment generated from the same blocks under pre- mining conditions. These results are primarily attributable to the excellent cover values documented to occur on the reclaimed lands. 1.4.3 CONCLUSIONS Both the USLE and SEDCAD 4 evaluations demonstrate that existing conditions will result in equivalent or lesser sediment contributions to surface runoff when compared with pre- mining levels as determined by baseline data. Both methodologies possess certain strengths and limitations and each offers a distinct and different view of the test required to meet Phase II criteria. The herbaceous cover and C- factor variables are critical to both approaches. Both methods account for and reflect the outstanding cover percentages established on the Trapper reclamation in the areas being evaluated. In a similar previous analysis conducted by CDRMS (SL -1 application), these methodologies were in effect validated and found to be conservative by comparing their results to direct measurements of sediment accumulations occurring in downgradient catchments at Trapper. For this particular application, the same type of verification exercise is not feasible as extensive disturbed areas also contribute runoff and sediment to the downgradient catchments. Trapper, however, does note that the currently pending application addresses areas with strong similarities to those previously evaluated and verified by CDRMS. The vegetative cover, cover type, topographic setting, and reclamation methodologies employed are all comparable. Given these similarities, Trapper believes it is reasonable to conclude that equivalent conditions, in terms of erosion and sediment transport, prevail on the reclaimed blocks addressed by this application. 15