715 AMBERJACK LN POOL24-0020 STORMWATER VOLUME CALCULATIONSComp. By:
Date:5/10/2024
Public Works Department
City of Atlantic Beach
Permit No:
Address:
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 = 7,500 ft2
Impervious Area (A) = 2,962 ft2 =39%
V = 0.92 x 2,962.0 x 9.3 /12
V = 2,112 ft3
Provided Storage:
Area 1 - Relative Elev.Area Storage Sideslope:3 :1
(ft)(ft2) (ft
3)
12.8 342 BOTTOM size:38 X 9
14.8 1,050 TOB size:50 X 21
Area 2 - Relative Elev.Area Storage
(ft)(ft2) (ft
3)
0.0 0 BOTTOM size:0 X 0
0.0 0 TOB size:0 X 0
Area 3 - Relative Elev.Area Storage
(ft)(ft2) (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) =1050.0 ft2
Depth to ESHWT from BOTTOM (d) =2.5 ft, default is 2.0 ft, verify onsite ESHWT
Pore Factor (pf) = 0.3 default is 0.4
Inground Storage Provided =787.5 ft3
Required Treatment Volume =2,112 ft3
Supplied Treatment Volume =2,180 ft3
Scott Walker PE
1,392
0
0
ATLANTIC BEACH, FLORIDA 32233
715 AMBERJACK LANE,
Retention W.R. for sending (Working Copy) 5/10/2024