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Calculations for Sediment Storage <br />10 -year, 24 -hour (MUSLE) = 85.80 tons (see Table 5) <br />85.80 tons x 2 (MUSLE) = 171.60 tons <br />171.60 tons x 2000 lb /ton = 0.098 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. The SEDIMOT II computer model was then run with <br />this input file and the resultant output file is presented as Table 5. <br />Results of the SEDIMOT II modeling show that the peak stage of the <br />10 -year, 24 -hour storm event will be 2.62 feet below the emergency <br />spillway. This allows for 2.61 ac. -ft. (including the 1.0 ac. -ft. <br />needed for pit pumpage) before any flaw would occur through the <br />emergency spillway. The 6" CMP was considered the smallest practical <br />size of pipe in order to increase detention time of the storm event <br />runoff and still be large enough not to freeze or plug up with the trash <br />rack installed (see Exhibit 7 -11 for detail of spillway). <br />Peak discharge from the principal spillway will be 0.19 cfs with 100.0 <br />percent basin trap efficiency and peak effluent sediment concentration <br />of 0.00 mg /l and 0.0 tons of sediment load discharged (see Table 5). <br />The pond can store up to 5.13 ac. -ft. of sediment or (104.7) 10 -year, <br />24 -hour (MUSLE) precipitation events with the principal spillway at the <br />inlet elevation of 6977.10. The inlet elevation was not changed from <br />the existing 36" CMP to minimize the disturbance of the culvert and the <br />embankment. Therefore, Pond 003 meets the requirements for storage and <br />treatment of the 10 -year, 24 -hour storm event. <br />Emergency Spillway <br />From the routing of the 25 -year, 24 -hour storm event with the SEDIMOT II <br />computer program, there is a peak inflow of 5.73 cfs at a peak stage of <br />7 -6b -5 Revised 8/27/86 <br />