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

Asd-5
II. SEDIMENTATION RESERVOIR EMERGENCY SPILLWAY DESIGN
• Problem: Determine hydraulic data of a V -shaped outlet
ditch, depth of flow at the design storm, and high
waterline elevation of the reservoir.
Solution: Maximum allowable velocity, Vmax - 3fps
q25 = 5.0 cfs (from Peak Discharge Calculations)
n = 0.03 (Manning coefficient for riprap)
sideslope = 2.1 (horizontal to vertical)
slope(s) = 0.01 feet/feet
Manning Equation:
q25 = 1.49 AR3s S%=
n
Hydraulic Data:
Q = 5 cfs
D = 0.95 feet
• A = 1.81 feet2
R = 0.42 feet
s = 0.01 feet/feet
n = 0.03
V = 2.77 fps
Assume reservoir high waterline to discharge the de-
sign storm is equal to the spillway invert elevation
plus the depth of flow in the outlet channel:
H.W.L. 25-year = 5226.10 + 0.95 = 5627.05'
To provide approximately one foot of freeboard, the
top of embankment shall be at an elevation of 5228.00.
III. SEDIMENTATION RESERVOIR COLLECTOR DITCH DESIGN - Topsoil Stockpile
Problem: Determine hydraulic data of a V-shaped collector
ditch, depth of flow at the design storm and max-
imum anticipated velocity.
•