PERMFILE66486

• Permit No: C1981020A
• IBM Index Class Name: Permit File
• Doc Date: 5/13/2002
• Section_Exhibit Name: Volume 6 APPENDIX As TO Cs
• Media Type: D
• Archive: Yes

Asa-5

II. SEDIMENTATION RESERVOIR EMERGENCY SPILLWAY DESIGN
Problem: Determine hydraulic data of a trapezoidal -shaped outlet
ditch, depth of flow at the design storm, and high waterline
elevation of the reservoir.
Solution: Maximum allowable velocity, Vmax - 3fps
22
q25
n = 0.03
sideslope = 4:1
slope(s) = 0.0]
w = 12
cfs (from Peak Discharge Calculations)
(Manning coefficient for riprap)
(horizontal to vertical)
feet/feet
feet
Manning Equation:
q25 = 1.49 AR'/, S '/3
n
Hydraulic Data:

Q = 22 cfs
p = 0.53 feet
A = x•48 feet'
R = 0.46 feet
s = 0.01 feet/feet
n = 0.03
V = 2.94 fps
Assume reservoir high waterline to discharge the design storm is
equal to the spillway invert elevation plus the depth of flow in
the outlet channel:
H.W.L. 25 year = 5301.40 + 0.53 = 5301.93'
To provide a minimum one foot of freeboard, the top of embankment
shall be at an elevation of 5304.00'
III. SEDIMENTATION RESERVOIR COLLECTOR DITCH DESIGN - North of CFA Access
Road, Bathhouse fi Wash Plant Area
Problem: Determine hydraulic data of a V -shaped
collector ditch, depth of flow at the design storm and
maximum anticipated velocity.

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