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<br />ATTACHMENT 4 <br />Responses to Inspection Report Dated June 24, 1981 <br />In reference to MLRB letter dated June 23, 1981, addressing <br />deficiencies in sediment control, Wyoming Fuel's Pit 1 sedimentation <br />plan will ultimately capture any runoff from the stockpile area in <br />Sedimentation Pond #1. Regrading of the area has been completed <br />which provides a clearer path for water toward Sedimentation Pond #1. <br />On July 9, 1981, Carol Russell of MLRB's staff inspected the <br />drainage for the stockpile area and found it satisfactory. (See <br />Inspection Report dated July 16, 1981). <br />The ditch which controls runoff from the shop and office area <br />located on the south line of Section 2 does not divert water into <br />an undisturbed area, however, the water could pond beside the haul <br />road. Therefore, a culvert will be installed to drain this area into <br />Pit #1. The following describes the culvert sizing and Figure 2 of <br />the April 14, 1981 permit application revised July 29, 1981 shows <br />its location: <br />Drainage Area ~ 5 acres <br />Ref: Procedures for <br />Determining Peak Flow <br />in Colorado, Soil Con- <br />servation Service, <br />USDA, March, 1977, <br />n = 0.025 <br />n 2 <br />i <br />Try 12" ~ culvert Q = 59.44 x ',(~) x (.25)'67 x (.O5)' <br />Page 80 1.6 inch/yr - 10 yr 24 hr storm <br />Page 21 CN = 85 (rangeland) <br />Page 11 Peak discharge = 980 csm/inch <br />for Type II Western Storm <br />Page 13 Mod. slope = 7.5 cfs/in <br />Page 62 runoff = 0.52 <br />7.5(.52) = 3.9 cfs @ 10 yr event <br />From Manning Q= 1'486 x A x R'67 x S'S <br />Q = 59.44 x 0.79 x (.40) x (0.22) <br />Q = 9.13 cfs> 3.9 cfs:•ok, Use a 12" ~ culvert <br />