PERMFILE69828

• Permit No: C1980007
• IBM Index Class Name: Permit File
• Doc Date: 12/11/2001
• Section_Exhibit Name: Exhibit 42 Sylvester Gulch Fan Site Information
• Media Type: D
• Archive: No

Avg. Slope 2.7X
Design Capacity 1.32 cfs
Design Velocity 3.15 f/sec. max.
Freeboard 0.30 feet min.
Manning's n 0.040 earth channel
Manning's Equation for Open Channel Flow
y , 1.4902/3 S1/2
n
R , r Vn l = ~{3.75)(.04)
1.49 S1/2 1.49 .027
• R - 0.6127. - estimated maximum hydrologic radius to achieve design
velocity. However since the actual hydraulic radius is 0.250, R = 0.4796.
A = Q/V = 3.75 cfs 0.3520 ft.2
Solve for channel size
A ~ Zd2
A = (1.0)(1.0)2
A = 1.0 ft.
R , Zd
2 +1
R
2,/ 1`+1
R ~ 0.250
V = 140 {0.250)2/3 (0.21)1/2
V = 2.43 f/sec which is less than 3.75 f/sec so design ok.
• Q = AV = (1.0 ft) (2.43 f/s)
Q 2.43 cfs which is greater than 1.32 cfs, so ok.