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

Asc-5
• II. SEDIMENTATION RESERVOIR EMERGENCY SPILLWAY DESIGN
Problem: Determine hydraulic data of a trapezoidal-shaped out-
let ditch, depth of flow at the design storm and high
waterline elevation of the reservoir.
Solution: Maximum allowable velocity, Vmax - 4.5fps
q25 = 35.0 cfs (from Peak Discharge Calculations)
n = 0.04 (Manning coefficient for riprap)
sideslope = 2:1 (horizontal to vertical)
slope(s) = 0.02 feet/feet
w = 8 feet
Manning Equation:
q25 = 1.49 AR's S2
n
Hydraulic Data:
Q = 35 cfs
D = 0.88 feet
• A = 8.59 feet2
R = 0.72 feet
s = 0.02 feet/feet
n = 0.04
V = 4.08 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 = 5231.00' + 0.88' = 5231.45'
To provide a minimum one foot of freeboard, the top
of embankment shall be at an elevation of 5233.00'.
III. SEDIMENTATION RESERVOIR COLLECTOR DITCH DESIGN - South of Stockpile
Problem: Determine hydraulic data of a V-shaped collector ditch,
depth of flow at the design storm and maximum anticipated
velocity.
Solution: Maximum Allowable Velocity, Vmax = 6 fps
• q10 = 16 cfs (from Peak Discharge Calculations)
n = 0.04 (Manning coefficient for riprap)
sideslope = 2:1 (horizontal to vertical)
slope(s) = 0.07 feet/feet