PERMFILE66875

• Permit No: C1981016
• IBM Index Class Name: Permit File
• Doc Date: 12/11/2001
• Doc Name: Sedimentation Control & Diversion Structure Calculations
• Section_Exhibit Name: APPENDIX XXI to Section XXI.8
• Media Type: D
• Archive: No

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• EAST h1INE LAYDOI.IPJ SEDIFIENTATION POND
Flow Design Calculations
1. Determine drainage area (Exhibit )
Area 6 = 1.28 acres = 28.8
Area 6A = 0.50 acres = 11.3 %
Area 6B = 0.94 acres = 21.2
Area 6C = 1.50 acres = 33.8 %
Area Highway = 0.22 acres = 5.D °~
Total Area = 4.44 acres = 100.1 %
2. Determine weighted curve number.
Area 6 = 28.8 Yo * 89 = 2563.2
Area 6A = 11.3°0 * 89 = 1005.7
Area 66 = 21.2% * 89 = 1886.8
Area 6C = 33.8% * 89 = 3008.2
Area Highway = 5.0% * 98 = 490.0
8953.9
_> 89.54
_> 90
3. Determine precipitation
l0yr -- 24 hr = 1.6"
25yr -- 24 hr = 1.8"
4. Determine volume of runoff for CN90 (Pp 70, SCS)
• l0yr -- 24 hr = 0.76 inches
= 3.37 acre inches
= 0.28 acre feet
A = 4.44 acres