93 GARDEN CT RES22-0253 Water Retention REVISION 12-13-22Comp. By:
Date:12/9/2022
Public Works Department
City of Atlantic Beach
Permit No:RES22-0253
Address:93 Garden Court, Atlantic Beach, FL 32233
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 = 6,777 ft2
Impervious Area (A) = 3,049 ft2 =45.0%
V = 0.92 x 3,049.0 x 9.3 /12
V = 2,174 ft3
Provided Storage:
Area 1 - Relative Elev. Area Storage Sideslope:2 :1 ESHWT Per Soils Report
(ft)(ft2) (ft
3)
0.0 0 BOTTOM size:-4 X -4 30
1.0 273 TOB size:X
Area 2 - Relative Elev. Area Storage
(ft)(ft2) (ft
3)
0.0 0 BOTTOM size:-4 X -4 25
1.0 723 TOB size:0 X 0
Area 3 - Relative Elev. Area Storage
(ft)(ft2) (ft
3)
0.0 0 BOTTOM size:-4 X -4 59
1.0 290 TOB size:0 X 0
Area 4 - Relative Elev. Area Storage
(ft)(ft2) (ft
3)
0.0 0 BOTTOM size:-4 X -4
1.0 148 TOB size:0 X 0 24 Assumed Standard
Area 5 - Relative Elev. Area Storage
(ft)(ft2) (ft
3)
0.0 0 BOTTOM size:-4 X -4
1.0 153 TOB size:0 X 0 24 Assumed Standard
Inground Storage: = A*d/pf
Total Storage Area at TOB (A) =1587.0 ft2
Depth to ESHWT from BOTTOM (d) =2.25 ft, default is 2.0 ft, verify onsite ESHWT
Pore Factor (pf) = 0.4 default is 0.4
Inground Storage Provided =1428.3 ft3
Required Treatment Volume =2,174 ft3
Supplied Treatment Volume =2,222 ft3
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137
362
145
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Retention Water Retention_Atlantic Beach 12/9/2022
By Toni Gindlesperger at 11:11 am, Dec 13, 2022