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APPENDIX M (cunt) <br />u <br />SMALL AREA EXEMPTION # 3 - SAE-3 <br />RIP RAP STOCKPILE :SURFACE WATER CONTROLS <br />To control the runoff of sediment from the Rip-rap stockpile, incised area and <br />sediment trap will be constructed. In accordance with applicable regulations, <br />these calculations will show that the sediment containment structures are <br />capable of retaining the design stone. <br />SPECIFICATIONS <br />Area of pile 13,200 sgft 0.30 acres Ave. Slope = <br />Veg. cover = 40 <br />Length = 150 ft Soil Group; mixed, use = C <br />PEAK FLOW CALCULATIONS <br />16% <br />1. From "Peak Flows In Colorado" P10 = 1.7" P25 = 2.1" <br />2. Runoff: CN disturbed and revegetated Use CN = 81 <br />RUNOFF Pe 10 = 0.42 inches Pe 25 = 0.67 inches <br />• <br />3. For Area = 1 acre 8 Slope = 16 °~ Slope Adj. Factor = 1.0 <br />4. For Hydraulic Length = 200 ft Equivalent Area = 0.58 <br />5. For CN = 68 and Area = 1 ac ; Peak Discharge ~ 2.8 ds~nch <br />6. Equivalent discharge <br />q10 = 1.18 cfs <br />q25 = 1.88 cfs <br />7. The ACTUAL DISCHARGE is 'Q10 = q10 ` A / Ae = 0.62 cfs <br />Q25 = 0.99 ds <br />8. VOLUME DISCHARGED is: X yr runoff • A/12 = 0.3" ` 33,600/12 <br />V10 = 462 cult <br />V25 = 737 tuft <br />SIZE OF THE SEDIMENT TRAP <br />Length = 30 Depth below Grade = <br />Width = 10 <br />2.5 <br />The VOLUME of the trap will be 750 CUBIC FEET. <br />• <br />Mc Vo11II PAGE M - 4 <br />10-1397 <br />