1889 BEACH RESO22-0049 Site storage Calcs 1889 Beach AveRetention 1889 BEACH RESO22-0049 Site storage Calcs 1889 Beach Ave 8/12/2022
Comp. By:
Date:8/12/2022
Public Works Department
City of Atlantic Beach
Permit No:_____________________________
Address:1889 Beach Ave
Required Storage Volume
Criteria:
Section 24-68 of the City of Atlantic Beach's Zoning, Subdivsion, and Land Development Regulations requires
that stormwater runoff from impervious areas be stored onsite. Volume to be retained is as follows:
V = CAR/12 which is the Modified Rational Method for estimating stormwater runoff
Where:V = Volume of Runoff to be stored (cubic feet)
C = Runoff Coefficient, 0.92, the difference between impervious area (C=1.0)
and undeveloped conditions (C=0.08).
A = Impervious Area (square feet)
R= 25-yr / 24-hr rainfall depth (9.3 inches for Atlantic Beach)
Onsite Storage Volume Required for Impervious Area:
Lot Area = 9,448 ft2
Impervious Area (A) = 3,594 ft2 =38.0%
V = 0.92 x 3,594.0 x 9.3 /12
V = 2,563 ft3
Provided Storage:
Area 1 - Relative Elev.Area Storage Sideslope:2 :1
(ft)(ft2)(ft3)
0.8 1,866 BOTTOM size:43.2 X 43.2
1,600 TOB size:40 X 40
Area 2 - Relative Elev.Area Storage
(ft)(ft2)(ft3)
0.5 119 BOTTOM size:7 X 170.0 75 TOB size:5 X 15
Area 3 - Relative Elev.Area Storage
(ft)(ft2)(ft3)
0.0 0 BOTTOM size:0 X 0
0.0 0 TOB size:0 X 0
Inground Storage:= A*d/pf
Total Storage Area at TOB (A) =1675.0 ft2
Depth to ESHWT from BOTTOM (d) =2.0 ft, default is 2.0 ft, verify onsite ESHWT
Pore Factor (pf) =0.4 default is 0.4
Inground Storage Provided =1340.0 ft3
Required Treatment Volume =2,563 ft3
Supplied Treatment Volume =-95 ft3
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RESO22-0049