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submitted by SCC for the Pond 016 watershed indicate an average cover of 47% in 2009. TR- <br />55 indicates that for a C type soil, 47% herbaceous vegetation cover (fair), would result in a <br />curve number of 81. In order to ensure that the ditches are properly armored and the pond <br />adequately sized, the model should consider the maximum runoff and sediment loading that <br />would occur during the life of the structures. Please either revise the curve numbers for the <br />reclaimed areas in the watershed to 81 or provide information supporting SCC's curve <br />number of 71. <br />29. For disturbed areas (the slide repair area), the curve number should be 94; SCC used 86. <br />Please either revise the SEDCAD run using a curve number of 94, or provide additional <br />information justifying the use of 86. <br />30. In the "Subwatershed Sedimentology Detail" of the SEDCAD run, SCC uses a C Factor of .035 <br />for reclaimed areas. It looks like that value is for derived from the tables in SEDCAD for "C <br />Factors for Permanent Pasture, Rangeland, Idle Land, and Grazed Woodland", "Canopy of <br />tall weeds or short brush (0.5m fall height), 50% canopy cover, 60% ground cover". Again, <br />looking at recent data, cover values for the reclaimed area are around 47%, which would put <br />the C Factor at approximately .053 (40% cover is .07; 60% is .035). Please revise the design <br />using a C Factor more representative of documented conditions, or provide additional <br />information supporting SCC's C factor of .035. <br />31. The inputs for hydrograph response time used by SCC are inconsistent with the currently <br />approved design and not representative of current ground conditions. The approved <br />designs for all of the post-mine channels indicate a "medium" response time and are based <br />on vegetation cover greater than or equal to 70%. The newly submitted design for TR-73 <br />uses a "slow" response time for all vegetated areas (both reclaimed and undisturbed) and a <br />"medium" response time for the disturbed areas. Please revise the SEDCAD run using a <br />response time of "medium" for all reclaimed areas and "fast" for disturbed areas associated <br />with slide repairs. <br />32. During the review process for SL-3, the Division identified postmining channels constructed <br />on the ground that do not have corresponding approved designs in the permit application <br />package. The figure below indicates the drainages (highlighted in red) in question. Please <br />either provide designs for the drainages or indicate where design information can be located <br />in the approved permit application package.