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Justifications for the Small Area Exemptions have been summarized <br />and are included in this Exhibit. Copies of the original CMLRD <br />• letters of approval are provided in Appendix B, CMLRD Letters of <br />Approval for Small Area Exemptions. <br />Sedimentation Pond L1 is designed to retain sediment from the <br />disturbed areas and retain runoff for the l0-year, 24-hour storm <br />event. As shown on the Loadout Area Surface and Groundwater <br />Hydrology Map, (Map 13), the pond is located near the northwest <br />corner of the permit boundary. This location allows for <br />retention of runoff through natural slope trends at the site and <br />via two (2) collection ditches and a culvert constructed along <br />the northern boundary and southeast corner of the permit area. <br />The total storage available within the sedimentation pond is <br />approximately 1.96 acre feet, 0.61 acre feet of sediment storage <br />and 1.35 acre feet of runoff storage. As shown on the East <br />Loadout Area Pond L1 and Drainage Structure Design Map, (Map 26), <br />the sedimentation pond is almost entirely incised with the <br />exception of a small embankment constructed with a crest <br />elevation of 5,227.0 feet, along the northeastern perimeter of <br />the pond. <br />The principal spillway is a 24-inch CMP culvert, with a 10-inch <br /> <br />"'°°°""-`° 168a Revised- June 1997 <br />oanoia+ m:eoe. ~+n <br />