PERMFILE62521

• Permit No: C1981025A
• IBM Index Class Name: Permit File
• Doc Date: 12/11/2001
• Doc Name: Final Engineering Calculations
• Section_Exhibit Name: 4.0 Appendix 4-B
• Media Type: D
• Archive: Yes

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T-1 AND T-2 SPILLWAYS OCT 0 2 1995 5/6
Since there is a ditch above the ponc~,s ~.]lat diverts all
surface flow away from t~s;blRT~d~~~a+~ e~,~ k flow that
T-1 and T-2 will need to andle is the 70 gpm flow from the
long pond or the decant flow from the 25-year event. The long
pond has the capacity to decant from one 6-inch pipe at 177 qpm
and two four inch pipes at 64 gpm each or 128 gpm. Design the
open channel for 305 gpm + 10% = 336 gpm (0.75 cfs)
OPEN CHANNEL SPILLWAY BETWEEN T-1 AND T-2 PONDS
FLOW IN A TRIANGULAR CHANNEL
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DEPTH D 0.550 FEET
SLOPE S 0.010 EXPRESS AS DECIMAL
Mannings "N" N 0.030 EXPRESS AS DECIMAL
SIDE SLOPE X 1.500 SLOPE = X:1
AREA=(W*D)+(X*D^2)= 0.45 FEET^2
WETTED PERIMETER=(W)+2((XD^2+D^2))^.5 1.98 FEET
R=AREA/WETTED PERMITER 0.23
V=(1.49/N)*(R^.667)*(S^.5)= 1.86 FEET/SEC
Q = A X V = 0.84 CFS
Q REQUIRED 336 GPM = 0.75 CFS 0.75
The spillway will be a triangular channel 0.55 feet deep
with 1.5h:1v side slopes. With a freeboard of 1.0' the
required depth of the spillway is 1.55 feet. The flow velocity
slow enough that erosion will not be a problem.
SPILLWAYS BETWEEN T-2 AND OUTFACE 001
DISCHARGE THOUGH A SUBMERGED TUBE
DIAMETER OF PIPE
AREA OF PIPE
C = LOSS COEFFICIENT
H = HEAD ON SPILLWAY
Q = C A (2GH)^.5
Q =
Q = ONE 4-INCH PIPE _
Q = TWO 4-INCH PIPES =
4.000 INCHES
0.0872 SQUARE FEET
0.500
0.167 FEET
0.1429 CUBIC FEET PER SECOND
64 GALLONS PER MINUTE
128 GALLONS PER MINUTE
DISCHARGE THOUGH A SUBMERGED TUBE
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DIAMETER OF PIPE
AREA OF PIPE
C = LOSS COEFFICIENT
H = HEAD ON SPILLWAY
Q = C A (2GH)^.5
Q =
Q = ONE 6-INCH PIPE _
6.000 INCHES
0.1963 SQUARE FEET
0.500
0.250 FEET
0.3937 CUBIC FEET PER SECOND
177 GALLONS PER MINUTE
P-9-9
09-27-95