PUBLIC WORKS EXAMPLE SHEET Comp. By: RLC
Date: 2/20/2015
Public Works Department
City of Atlantic Beach
Permit No: Example
Address: 371 8TH STREET,ATLANTIC BEACH, FL
Required Storage Volume
Criteria:
Section 24-66 of the City of Atlantic Beach's Zoning, Subdivsion, and Land Development Regulations
requires that the difference between the pre-and postdievelopment volume of stormwawter runoff be
stored on site. Volume of Runoff is defined as follows:
V=CAR/12
Where: V=Volume of Runoff
C =Coefficient of Runoff
A=Area of lot in square feet
R=25-yr/24-hr rainfall depth (9.3-inches for Atlantic Beach)
Preclevelopment Runoff Volume:
Lot Area (A) = 10,84- ft'
Runoff Coefficient
Area Lot Area
Description (ft) (ft) 11C., Wtd "C"
Impervious 3,784 10,843 1.00 0.35
Pervious 7,059 10,843 0.20 0.13
Runoff Coefficient(C) 0.48
Runoff Volume
V= 0.48 x 10,843 X 9.3 12
V= 4,027 ft 3
Postclevelopment Runoff Volume:
Lot Area (A) = 10 3 43 ft2
Runoff Coefficient
Area Lot Area
Description (ft) (ft) 11C., Wtd "C"
Impervious 10.84 1.00 0.43 50% Impervious Surface Limt
Pervious 6 140 1 C, 8 4 0.20 0.11
Runoff Coefficient (C) 0.55
Runoff Volume
V= 0.55 x 10,843 x 9.3 12
V= 4,597 ft3
Required Storage Volume
DV= Postdevelopment Runoff Volume- Predevelopment Runoff Volume
DV= 4,597 4.027
DV= 570 ft3
Retention Stormwater CaIcs—WOOD 2/20/2015
1j:
0 .it Comp. By: RLC
Date: 2/20/2015
Public Works Department
City of Atlantic Beach
Permit No: Example
Address: 371 8TH STREET,ATLANTIC BEACH, FL
Provided Storaqe�
Elevation Area Storage
(ft) (ft)
0 BOTTOM AREA'A'
82 TOB
Elevation Area Storage
(ft) (ft) (ft')
0.0 57 0 BOTTOM AREA'B'
0.5 226 1_1 TOB
Elevation Area Storage
(ft) (ft)
1.0 0 0 BOTTOM
0.3 0 0 TOB
Inground storage=A*d*pf
A=Area= 480.0
d=depth to ESHWT= 3.0 ESHWT -per geotech if obtained
pf= pore factor= 0.3
Inground Storage= 432.0 ft 3
Required Treatment Volume= 570 ft3
Supplied Treatment Volume= 585 ft3
Retention Stormwater Calcs—WOOD 2/20/2015