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c. An appropriate non-clogging dewatering device will be installed to maintain a 10-year, 24- <br />• hour storage volume. <br />d. Appropriate combinations of principal and emergency spillways to safely discharge the <br />runoff from a 25-year, 24-hour precipitation or larger event, as required by the CDMG's <br />regulations, will be installed. <br />The sediment storage capacity of the sedimentation pond will be periodically monitored to ensure that <br />at least one year of sediment storage is available beneath the principal spillway inlet (based on the <br />U.S.L.E. or the equivalent sediment storage of one 10-year, 24-hour storm event based on the <br />M.U.S.L.E.). When adequate capacity is no longer available, sediment removal or other corrective <br />actions will be taken to restore adequate sediment storage capacity to the pond. <br />Corrective action required to restore adequate sediment storage capacity may include the following: <br />1. Raise the spillway and redesign the pond in order to restore adequate storage capacity <br />and to comply with the applicable regulations. <br />• 2. Excavate the pond area and enlarge the sediment storage capacity. <br />The excavated material suitable for topsoil will be salvaged in a stockpile used for reclamation. The <br />excavated material that is not suitable for atopsoil-like medium will be graded into the surrounding <br />topography within the disturbance area, topsoiled, and revegetated in accordance with WFC's <br />approved reclamation plan. Site specific conditions will determine the construction methods and <br />equipment utilized at the time of excavation. Sediment removal and water discharges will be <br />conducted consistent with the approved mining permit, the NPDES permit, and CDMG Regulations <br />Section 4.05.6(3)(b). All sedimentation ponds will be inspected quarterly under the supervision of a <br />registered professional engineer and reported to the CDMG. <br />Pit dewatering will be primarily a seasonal occurrence. The dewatering process wilt be a sporadic, <br />operation-controlled occurrence depending on various factors which may include the location of the <br />pit inflows, the location of standing water in the pit, or the location within the pit of the overburden and <br />coal removal operations. When pit dewatering is required, the anticipated dewatering rate will be in <br />the range of one to two cubic feet per second or less. Most dewatering discharges will be directed to <br />007 East and West Ditches, which drains into Pond 007. However, direct pit pumping into Pond 007 <br />• (Revised ~/zoos) 2.05.3(3) - 6 <br />