1987-12-01_PERMIT FILE - C1981017 ‎(167)‎

• Permit No: C1981017
• IBM Index Class Name: PERMIT FILE
• Doc Date: 12/1/1987
• Doc Name: Overland Conveyor Site Dainage Calculations July 30, 1989
• Section_Exhibit Name: Chapter III MR-22
• Media Type: D
• Archive: No

5. DISCHARGE TYPE II STORM
• Unit 1
Ave.% Discharge Peak Discharge in CFS
Sub Area Slope CN CFS/In.Runoff 25 yr. 10 yr. 5 yr.
Yard 1 80 85 11 13.86 8.80 7.15
2 2 90 6 9.72 6.54 5.58
& Waste Pile
1 11 60 10 2.00 6.00 0.30
2 57 85 9* 11.34* 7.20* 5.85*
3 8 100 10 26.00 2.00 18.00
Note Discharge if all surface flows allowed to accumulate at one point.
*Flow diverted around pond by ditch
6. POND DESIGN
For Capacity and Release Rates
Runoff Required Storage in Ac. Ft.
Sub Area (inches) - As Functions of Release Rate
Area s .mi . 25 yr. 10 yr. 30 CSM 60 CSM 100 CSM 200 CSM 300 CSM
2
Yard 0.0162 2.88 1.89 25 yr. 2.30 1.95 1.63 1.35 1.20
10 yr. 1.35 - 1.06 0.90 0.68 0.60
Pond & 0.0263 2.80 2.60 25 yr. 3.50 3.06 2.66 2.25 2.00
Waste 0.0425 5.68 4.49 10 yr. 1.30 1.00 0.80 0.60 0.50
Pile
Runoff Volume 10 year Storm w/o Release Flow
Yard 1.63 ac. ft.
Pond & Waste Pile 3.65 ac. ft.
TOTAL 5.28 ac. ft.
Runoff Volume 25 Year Storm
Yard 2.49 ac. ft.
Pond & Waste Pile 3.93 ac. ft.
TOTAL 6.42 ac. ft.
2 CSM = cubic feet/second/sq. mile
8