2325 Beachcomber. PPI22-0001 RequiredStorageVolumeComp. By:
Date:
Public Works Department
City of Atlantic Beach
Permit No:RES21-003
Address:2325 Beachcomber Trail
Required Storage Volume
Criteria:
Section 24-66 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 = 16,766 ft2
Impervious Area (A) = 4,168 ft2 =24.9%
V = 0.92 x 4,168.0 x9.3/ 12
V = 2,972 ft3
Provided Storage:
Area 1 - FRONT Area Storage Sideslope:4 :1
(ft)(ft2) (ft
3)
7.0 816 BOTTOM size:X
7.5 1,381 TOB size:X
Area 2 - BACK Area Storage
(ft) (ft
2) (ft
3)
7.0 294 BOTTOM size:X
7.5 813 TOB size:X
Area 3 - Relative Elev. Area Storage
(ft) (ft
2) (ft
3)
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) =2194.0 ft2
Depth to ESHWT from BOTTOM (d) =2.5 ft, default is 2.0 ft, verify onsite ESHWT
Pore Factor (pf) = 0.4 default is 0.4
Inground Storage Provided =2194.0 ft3
Required Treatment Volume =2,972 ft3
Supplied Treatment Volume =3,020 ft3
549
277
0
4/6/2022
Retention 2325 Beachcomber Trail_Calcs 4/12/2022
Reynold
D.
Peterson
Digitally signed
by Reynold D.
Peterson
Date: 2022.04.12
09:42:53 -04'00'