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surface runoff frcmm entering this ditch. The material stoc}g~i1e and associated drainage structures will be located a miniiman of 20 feet from the toe of the adjacent. slope. 'This buffer zone will effectively reduce the velocity of overland flow coming off this slope aryl minimize any potential for erosion of the diversion berm. Zhe ccxaimP.,t fences, ditch aryl berms will be used to control disturbed area runoff fziatt the fan installation, the lower portion of the existing powerline access road, and the cut material stocl~ile. The locations of these drainage control structures are shown on the South Mine Fan Installation Map, (Map 30) . All berms and sediment fence will be inspected on a regular basis for damage or erosion arri any problem areas will be repaired. The proposed sediment fence should adequately control surface runoff and csxi i ant yields from proposed disturbance areas. The sediment fence is designed to safely pass all runoff frwn the contributing drainage area resulting frwn a 10-year, 24-Hour storm event. Design calculations for the sediment fence are included in Appendix C, SYnall Area F7cemption Hydrologic Docimientation. A small ephemeral tributary drainage is located approximately twenty-five feet east of the proposed fan installation. In order to evaluate the need for a flood protection berm to isolate the fan installation frcmi possible flooding, flood stage calculations were c~nplete3 for this drainage. These calculations are presented in Appendix C, Small Area EScemption Hydrologic Docwrentation, and indicate that a protective structure is not r~eoessazy since the peak dim-name from a 100-year, 24-hour storm event would be contained by the existing drainage channel. Since all applicable exemption requirements of rule 4.05.2(3) are adequately addressed, EE'CI respectfully requests approval of a Small Area EXemption for the South Mine Fan Installation. • C\...860\TR16.REV u/o6/93 lpm 201Ra Revised -November 1993