SW6230603_Design Calculations_20240510 (2)

4D Site Solutions, Inc.
DESIGN REQUIREMENTS:
A. Pass the storm event
Aberdeen US 15-501 DG-Detention Basin Pre-Development Runoff-10-yr
Drainage Area,(DA)= 1.53 acres
Intensity,(I)= 7.84 inches/hr
Composite Runoff Coefficient,(C)=> 0.31
Maximum Release Rate,(Q10)=> 3.72 cfs
Aberdeen US 15-501 DG-Detention Basin Post-Development Runoff-10-yr
Drainage Area,(DA)= 1.53 acres
Intensity,(I)= 7.84 inches/hr
Composite Runoff Coefficient,(C)=> 0.67
Peak Release Rate,(Q10)=> 8.04 cfs
Detention Pond Stage-Storage Function
Contour Contour Incr. Accum. Stage
Elev. Area Storage Storage(S) (Z)
(ft) (sf) (cf) (cf) (ft) In(S) In(Z) Z est
346.30 11,166 - - - -
346.80 11,791 5,739 5,739 0.50 8.66 -0.69 0.52
347.30 12,430 6,055 11,795 1.00 9.38 0.00 1.00
347.80 13,083 6,378 18,173 1.50 9.81 0.41 1.49
348.30 13,750 6,708 24,881 2.00 10.12 0.69 1.99
348.80 14,432 7,046 31,927 2.50 10.37 0.92 2.51
Regression Output:
b= 1.09 (X Variable Coeff)
Ks= 11,756 (eY-n'terOePt)
Stage-Storage Equation is of the form:S=(Ks)(Z)b
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4D Site Solutions, Inc.
Infiltration
Infiltration rate= 0.1 in/hr
2.31E-06 ft/s
SF of Retention 11166 sf
Outflow from infiltration= 0.03 cfs
Primary Spillway
Width of Spillway(Approx.)= 1 feet
Weir Coefficient= 3.3
Crest Elevation= 346.60 feet
Emergency Spillway
Width of Spillway(Approx.)= 15 feet
Weir Coefficient= 3.3
Crest Elevation= 347.80 feet
Summary of Results
Maximum Release Rate,(Qio)= 3.72 cfs
Infiltration Rate,(Qio)= 0.03 cfs
Overflow Rate,(Q10)= 2.55 cfs
Water Surface Elev.@ Outlet(Q10)= 347.44 feet
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4D Site Solutions, Inc.
Inflow Hydrograph-10-yr
Peak Inflow,(Qp)_> 8.04 cfs
Time to Peak Calculation: CN= 85 P= 5.46 in. S= 1.76 in.
Q*= 3.80 in. (depth of runoff)
Vol= 21,080 cf (vol.of runoff)
Time to Peak,(Tp)=> 31.5 minutes
(SCS TR-55)
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