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<br /> <br /> <br />~J <br />Drainage Area <br />Pit (acres) <br />4 139.9 <br />5 & 6 47.7 <br />TABLE 1 <br />SEDIMENT PONDS <br />SEDIMENT AND FLOOD VOLUMES <br />10-year, 24-hour <br />Runoff 1 <br />(inches) <br />.70 <br />.70 <br />Runoff Sediment* Pond <br />Volume Volume Size <br />ac.ft. ac.ft. ac.ft. <br />8.16 .46 8.62 <br />2.78 .17 2.95 <br />* NOTE: for disturbed areas, the SCS has recommended against using the USLE. <br />Sediment volume was calculated based on average annual runoff of 5 <br />inches/year, an assumed sediment load of 10,000 mg/1 year round and the <br />drainage area of each pit. Sediment volume is computed in <br />acre-feet/year, assuming a density of 80 pcf. <br />1. Determined using a CN of 86 for the mine pits and a 10-year 24-hour <br />rainfall of 1.80 inches. <br />2-85 <br />V-8 <br />