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2-32 <br />Permanent diversion ditches used to route water from the pile to <br />the sediment pond will be sized to pass the runoff resulting from <br />a 100-year precipitation event. The sediment pond has been sized <br />to store the runoff from two 10-year, 24-hour precipitation events <br />and the sediment generated from over a six year period. The <br />sediment pond spil{ways have been designed to Pass a 25-Year, <br />24-hour event as required by CMLR regulations. A cleanout marker <br />will be installed to indicate the level at which sufficient <br />storage remains to store both the runoff and sediment generated by <br />the 10-year, 24-hour precipitation event. Dewatering of the <br />reservoir will be accomplished with a gravity flow, eight inch. <br />gated pipe installed so that the pond can be dewatered to below <br />• the level of maximum sediment storage. <br />Precipitation from a 10-year event is approximately 1.4 inches; <br />from a 25-year event, 1.7 inches; and 2.4 inches from a 100-year <br />event. Interim refuse disposal practices and final grading and <br />reclamation plans will be designed to minimize runoff from these <br />events. <br /> <br />2/16/89 <br />