HYDRO22857

• Permit No: C1982056
• IBM Index Class Name: Hydrology
• Doc Date: 9/24/1985
• Doc Name: SEDIMENTATION POND E AS-BUILT CERTIFICATION FOR FISH CREEK TIPPLE PERMIT NO C-036-81
• Permit Index Doc Type: SEDIMENT POND INSPECTIONS
• Media Type: D
• Archive: No

' REVISED
7/30/85
~-. Table 2
SEDIMENTATION POND E DESIGN CALCULATIONS
(Continued)
' Modified Universal Soil Loss Equation:
Y = 95 (Q gp) 0.56 K LS CP
' = 95 ((1.52)(17.7)) 0.56(0.2)(2.80)(1.0)(1.0)
= 336 tons x 2000 (lbs/ton) / 60 (lbs/cu.ft.)/43,560(sq. ft/ac. L~
' = 0.26 ac-ft.
f
4
64
0) = 0.
ac.
t.
Required Sediment Volume: 0.26 ac-ft x (100/
Required Sediment Cleanout: When pond is 60% full of sediment.
1
RUNOFF VOLUME:
' 1.8 in. rainfall and Curve Number 82 = 0.52 in, runoff ~-
35 ac watershed x 0.52 (in. runoff)/12(in./ft.) = 1.52 ac-ft of runoff
' volume

~, TOTAL VOLUME:
' 0.64 ac-ft of sediment volume + 1.52 ac-ft of runoff volume = 2.16 ac-ft ~
of total volume

EMERGENCY SPILLWAY:
' - Design for 25-yr, 24-hr event = 2.2 in. rainfall ~~
- 35 ac watershed ~~

' - AMC II Curve No. 82 J
ff
i
l
f
6
A
runo
area
s
~
verage s
ope o
-
- Slope correction factor = 1.11
1 ~_
- 2.2 in. rainfall @ curve No. 82 = 0.83 in. runoff
PEAK FLOW:
31 cfs/in. runoff x 0.83 in. runoff x 1.11 = 28.6 cfs L~

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