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The following briefly describes the input and output from the small area exemption SEDCAD+ . <br />analyses. <br />Input Sun¢nary <br />10-yr. 29-hr Precipitation 1.6 in. <br />CN Factor 46 <br />K Factor 0.25 <br />CP Factor 0.075 <br />Output Sum¢nary <br /> Runoff Volumes and Sediment <br />Topsoil Pile 1 0. 0 <br />Topsoil Pile 2 0. 0 <br />Topsoil Pile 3 0. 0 <br />Substation: There is an electrical substation located in the northwest corner of the <br />facilities area as shown in Exhibit 12-2, Surface Water Control Plan Map (Revision 10, dated <br />06/06). The substation is enclosed within a 30 by 40 foot area which is graveled and <br />fenced. Also associated with the substation is a small disturbance area outside the chain- <br />link fence. Runoff from the substation area does not drain to the Truck Loop Pond and is <br />controlled using a sediment fence. The location of the sediment fence is shown on Exhibit <br />12-2 (Revision 10, dated 06/06). The sediment fence is designed to safely pass the peak <br />discharge from a 10-year, 24-hour event. The design demonstration is presented in Appendix <br />12-2, S7na11 Area Exemption Demonstrations. Given the limited size of the disturbance area <br />and the demonstration that a sediment fence provides adequate control, HGTI requested, and <br />received CDMG approval to permit this area as a small area exemption. <br />Office/Parking Lot/Leach Field: There is an office/change building, parking lot, and leach <br />field on the west side of the facilities area as shown on Exhibit 12-2, (Revision 10, dated <br />06/06). Total disturbance associated with the office and parking area is approximately 0.3 <br />acres. The disturbance associated with the existing leach field (0.45 acres) has been <br />successfully revegetated. Runoff from these areas does not drain to the Truck Loop Pond and <br />is controlled with a sediment fence. The location of the sediment fence is shown on Exhibit <br />12-2 (Revision 10, dated 06/06). The sediment fence is designed to safely pass the peak <br />discharge from a 10-year, 29-hour event. The design demonstration is presented in Appendix <br />12-2, Small Area Exemption Demonstrations. Given the limited size of the disturbance area <br />and the demonstration that a sediment fence provides adequate control, HGTI requested, and . <br />received CDMG approval to permit this area as a small area exemption. <br />TR-07 9 Revised 06/06 <br />