1892 Sea Oats Dr_RES23-0008 CALCS_REVISION 1-24-23.Comp. By:
Date:
Public Works Department
City of Atlantic Beach
Permit No:
Address:1892 SEA OATS DRIVE
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 = 10,954 ft2
Impervious Area (A) = 4,643 ft2 =42.4%
V = 0.92 x 4,643.0 x 9.3 /12
V = 3,310 ft3
Provided Storage:
Area 1 - NORTH SIDE Area Storage Sideslope:4 :1
(ft)(ft2) (ft
3)
7.7 158 BOTTOM
8.7 1,108 TOB
Area 2 - FRONT Area Storage
(ft)(ft2) (ft
3)
7.7 150 BOTTOM
8.7 491 TOB
Area 3 - SOUTH SIDE Area Storage
(ft)(ft2) (ft
3)
7.7 63 BOTTOM
8.7 558 TOB
Inground Storage: = A*d/pf
Total Storage Area at TOB (A) =2157.0 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 =2157.0 ft3
Required Treatment Volume =3,310 ft3
Supplied Treatment Volume =3,421 ft3
Reynold Peterson, P.E.
633
321
311
1/2/2023
Page 1 Retention
Reynold D.
Peterson
Digitally signed by
Reynold D. Peterson
Date: 2023.01.02
12:07:41 -05'00'
By Toni Gindlesperger at 9:39 am, Jan 24, 2023