1892 SEA OATS DR RES23-0008 _Calcs_ REVISION 3-15-23Comp. 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) = 4,658 ft2 =42.5%
V = 0.92 x 4,658.0 x9.3/ 12
V = 3,321 ft3
Provided Storage:
Area 1 - NORTH SIDE Area Storage Sideslope:4 :1
(ft)(ft2) (ft
3)
7.7 250 BOTTOM
8.7 892 TOB
Area 2 - FRONT Area Storage
(ft) (ft
2) (ft
3)
7.7 168 BOTTOM
8.7 541 TOB
Area 3 - SOUTH SIDE Area Storage
(ft) (ft
2) (ft
3)
7.7 100 BOTTOM
8.7 736 TOB
Inground Storage: = A*d/pf
Total Storage Area at TOB (A) =2169.0 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 =2169.0 ft3
Required Treatment Volume =3,321 ft3
Supplied Treatment Volume =3,513 ft3
Reynold Peterson, P.E.
571
355
418
3/8/2023
Page 1 Retention
Reynold D.
Peterson
Digitally signed by
Reynold D. Peterson
Date: 2023.03.09
08:12:27 -05'00'
By Toni Gindlesperger at 9:15 am, Mar 15, 2023