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Calculations for Sediment Storage <br />10 -year, 24 -hour (MUSLE) = 8837.36 tons (see Table 5) <br />8837.36 tons x 2 (MUSLE) = 17674.7 tons <br />17674.7 tons x 2000 lb /ton = 10.14 ac. -ft. <br />80 (lbs /ft x 43560 ft /ac. <br />Results <br />10 -year, 24 -hour Runoff Volume and Sediment Storage Volume <br />All previously cited data was entered into a batch input data file which <br />is presented in Table 4. Table 5 contains the resultant output file <br />from the SEDIMOT II computer model run with this input file. <br />Results of the SEDIMOT II modeling show that the peak stage of the <br />10-year, 24-hour storm event will be 2.80 feet below the maximum stage <br />of Pond 002. This will allow for 22.25 ac. -ft. of storage for pit <br />pumpage and ground water and other surface water inflow into the pond <br />before overtopping of the road. This is very conservative amount of <br />additional storage since it assumed no flow through the . principal <br />spillway. The peak discharge from the principal spillway will be 4.71 <br />cfs at a depth of flow of 0.84 ft. The Pond 002 has a peak effluent <br />sediment concentration of 0.0 mg /1 with 100.0 percent basin trap <br />efficiency and 0.0 tons of sediment load discharged (see Table 5, Storm <br />Event Summary). The pond can store up to 267.36 ac. -ft. of sediment <br />volume or (52.7) 10 -year, 24 -hour (MUSLE) precipitation events with the <br />principal spillway at the. inlet elevation of 6611.20. Therefore, Pond <br />No. 002 meets the requirements for storage and treatment of a 10 -year, <br />24 -hour storm event. <br />Emergency Spillway <br />The batch input data file and the resultant output file from the SEDIMOT <br />II model analysis for a 25 -year, 24 -hour storm event are presented as <br />Table 6 and 7, respectively. From the routing of the 25 -year, 24 -hour <br />7 -6a -5 Revised 8/27/86 <br />