331 2nd ST PPI24-0001_atlantic beach _Calcs_ss.Comp. By:
Date:
Public Works Department
City of Atlantic Beach
Permit No:
Address:331 2nd Street
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 = 7,000 ft2
Impervious Area (A) = 2,767 ft2 =39.5%
V = 0.92 x 2,767.0 x9.3/ 12
V = 1,973 ft3
Provided Storage:
Area 1 - FRONT Area Storage Sideslope:4 :1
(ft)(ft2) (ft
3)
8.5 25 BOTTOM
9.0 207 TOB
Area 2 - Area Storage
(ft) (ft
2) (ft
3)
8.5 543 BOTTOM
9.0 978 TOB
Area 3 - Area Storage
(ft) (ft
2) (ft
3)
0 BOTTOM
0 TOB
Inground Storage: = A*d/pf
Total Storage Area at TOB (A) =1185.0 ft2
Depth to ESHWT from BOTTOM (d) =3.5 ft, default is 2.0 ft, verify onsite ESHWT
Pore Factor (pf) = 0.4 default is 0.4
Inground Storage Provided =1659.0 ft3
Required Treatment Volume =1,973 ft3
Supplied Treatment Volume =2,097 ft3
Reynold Peterson, P.E.
58
380
0
11/14/2023
Retention 331 2nd ST_atlantic beach _Calcs 11/14/2023
Reynold
Peterson
Digitally signed
by Reynold
Peterson
Date: 2023.11.14
06:28:57 -05'00'