PERMFILE105841

• Permit No: C1981048
• IBM Index Class Name: Permit File
• Doc Date: 12/11/2001
• Section_Exhibit Name: EXHIBIT V-3
• Media Type: D
• Archive: No

Ditch Design
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1. Ditch: 22-D3
2. Description: Diversion ditch around active mining pit.
3. Grade of Ditch: .014 or 1.4~
4. Area Brained: 107 acres
5. Peak Discharge: 154 cfs w/1.25 correction factor
6. Ditch Design:
Ditch lining rock
n = .045
Use ditch w/"V" walls 1:2 slope
A = 2D2; P = wetted perimeter =~4.472D
Rh = A/P = .4472D
_ (1.49/n) A (Rh)2/3 (S)1/2
Q = (1.49/.045)(2D2)(.4472D)2/3(.014)1/2
• Q = (33.11)(2D2)(.4472D)2/3(.118)
Q = 7.81 (D2)(D2/3)(.5848)
Q = 4.56 D8/3
154/4.56 = B8/3 = D2.67
D = 3.7 feet deep
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