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<br />September 19, 2001 <br />Page 2 of 3 Pages <br />Based on the report of Reference 3) above, [he capacity of the pond was slightly less than its <br />design capacities at the time of the June 2001 survey, and needed to be cleaned (0.02 acre feet of <br />sediment over the design 0.84 acre feet, 0.02 acre feet less than the 1.36 acre feet of design water <br />storage). <br />The approved design is found in Exhibit 7, Tab 13, Appendix A, 10-14-1998. The bottom of the <br />pond is at a design elevation of 6579.00 feet. The approved design is for a maximum of 0.84 acre <br />feet of sediment storage at a top of sediment storage level of 6581.17 feet with a detained pond <br />capacity of 1.36 acre feet. By reference 3) above, Colowyo Coal Company, L.P. (Colowyo) <br />reports that the pond had a storage volume of 1.3424 acre feet. <br />This pond appeared to be covered with ice or snow in an aerial photograph (aerial inspection) <br />taken on January 9, 2001. There was surface flow from upland watersheds into this pond, and an <br />estimated dischazge of 0.35 cubic feet per second (cfs) from this pond, on February 20, 2001 <br />(Division inspection). There was an estimated dischazge of 0.2 cfs from this pond on March 21, <br />2001 (Division inspection). There was an estimated discharge from this pond of 0.03 cfs on June <br />19, 2001 (Division inspection). There is a source of water to this pond other than surface runoff, <br />and historically, this pond has a continuous discharge. The level of the water in the pond is <br />usually at orjust above the lowest dewatering weep hole. Thus, generally, any surface inflow, of <br />any magnitude, will trigger a simultaneous additional outflow discharge. <br />The operator advised that this pond is scheduled for cleaning later this month (Division <br />inspection of September 12, 2001). <br />The Stoker Siding Pond (Outfall OOSA) <br />The condition and state of repair of this pond appears to have been good. <br />The approved design is found in Exhibit 7, Tab 13, Appendix E, 04-17-1998 of the Division <br />permit. The bottom of the pond is at an elevation of 6321.80 feet. The approved design is for <br />0.02 acre fee[ of sediment storage at a top of sediment storage level of 6322.35 feet. By reference <br />3) above, Colowyo Coal Company, L.P. (Colowyo) reports that the pond was cleaned in <br />September of 1998, and that the current storage volume is 0.6268 acre feet. This report also <br />indicates that the pond was excavated more than the design. The 0.6268 acre feet capacity is <br />more than enough to meet design requirements. <br />There appeared to be a level of water, frozen or with snow cover, in this pond in an aerial <br />photograph (aerial inspection) taken on Januazy 9, 2001. There was an estimated discharge of <br />0.03 cubic feet per second discharge from this pond at the time of a Division inspection of <br />February 20, 2001. There was water in, but no dischazge from, this pond at the time of a March <br />21, 2001 Division inspection. <br />