PERMFILE50611

• Permit No: C1981041A
• IBM Index Class Name: Permit File
• Doc Date: 10/11/2002
• Doc Name: A-2 Part 1
• Section_Exhibit Name: Tab 13 Appendix 13-2 TOC to pg RSN-51
• Media Type: D
• Archive: Yes

Using the curve number and average slope, a peak discharge in
cfs/inch of runoff was selected from Figure D-2.
Equivalent peak discharge was determined by:
Qe = (peak discharge cfs/inch)(inches of runoff)
From Table E-1 a watershed slope correction factor was determined
and the equivalent peak discharge corrected as follows:
Qc = (equivalent peak disc harge)(correction factor)
Actual peak discharge was then determined by:
Qa = equivalent peak discharge (actual drains a area)
equivalent drainage area
Using peak discharge, channels, flumes, and spillways were sized
using Manning's equation for open channel flow as follows:
V = 1.49/n(R)2/3(S)~
Where: V = Velocity feet/second
N = Roughness coefficient
R = Hydraulic radius = A/WP
S = Slope in ft/ft
To find capacity
. Q = Capacity in cubic feet per second
V = Velocity in feet per second
A = Cross-sectional area of channel, flume, or spillway
Culverts were sized usirig culvert design criteria, as set forth in
the following references:
Hydraulic Charts for the Selection of Highway Culverts
Hydraulics Engineering Circular No. 5 U.S. Department of
Transportation Federal Highway Administration April 1977
Handbook of Steel Drainage and Highway Construction
Product, American Iron and Steel Institute 1971
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INFO - 2 (New 10/81)