2001-12-11_PERMIT FILE - C1981010A ‎(4)‎

• Permit No: C1981010A
• IBM Index Class Name: Permit File
• Doc Date: 12/11/2001
• Doc Name: A Review of Potential Alluvial Valley Floors & Possible Impacts
• Section_Exhibit Name: APPENDIX H Section 1
• Media Type: D
• Archive: Yes

~e~
. where:
V = velocity,
n = Mapping's roughness coefficient,
R = hydraulic radius, and
S = slope of water surface.
To apply this to the reach of interest, the following assumptions
must be made:
• rectangular river channel, width » depth,
• n constant, and
`~ S constant and =S- (slope of channel bn*.*or.!).
These assumptions are not unreasonable through the Big Bottom
area. The Manning equation can then be converted to the follow-
ing form:
ri 5 1s Q,a
V - [~1-ter)-. B
where:
B channel bottom width.
In other words, velocity is proportional to flow to the 0.4 power.
`Thus, using the mean Station 1 flow (from 29 to 31 August) of
230 cfs:
~~
4-8