45 Simmons Rd - COMM22-0034 Unimproved - Pre Development - Runoff Calcs REVISION 11-2-22Retention 45 Simmons Rd - Unimproved 10/19/2022
Comp. By:
Date:
Required Storage Volume
NAME
10/19/202
Public Works Department
City of Atlantic Beach
Permit No:
Address:
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:
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)
POND 1 NO WALL SLOPE
X
X
X
X
X
X
X
X
2.5
_____________________________
_____________________________
6,857
6,857
3
9.0
10.8 0 0
0.0
0.0 0 0
0.0
0.0 0 0
0.0
0.0 0 0
2.0
Criteria:
V = CAR/12
Onsite Storage Volume Required for Impervious Area:
Lot Area = ft2
Impervious Area (A) =
V = 0.08 x x 9.3 /12
V = ft3
Provided Storage:
Area 1 - Relative Elev.Area Storage Sideslope::1
(ft)(ft2)(ft3)
BOTTOM size:
TOB size:
Area 2 - Relative Elev.Area Storage
(ft)(ft2)(ft3)
BOTTOM size:
TOB size:
Area 3 - Relative Elev.Area Storage
(ft)(ft2)(ft3)
BOTTOM size:
TOB size:
Area 3 - Relative Elev.Area Storage
(ft)(ft2)(ft3)
BOTTOM size:
TOB size:
Inground Storage:= A*d/pf
Total Storage Area at TOB (A) =ft2
Depth to ESHWT from BOTTOM (d) =ft, default is 2.0 ft, verify onsite ESHWT
Pore Factor (pf) =0.4 default is 0.4
Inground Storage Provided =ft3
Required Treatment Volume =ft3
Supplied Treatment Volume =ft3
ft2 100.0%
6,857.0
425
0 0 0 10
0
0 0 0 0
0
0 0 0 0
0
0 0 0 0
0
0.0
0.0
425
0
By Toni Gindlesperger at 5:36 pm, Nov 02, 2022