376 10TH ST RES21-0373 Public Works Calcs calcs_ss_1Comp. By:
Date:
Public Works Department
City of Atlantic Beach
Permit No:
Address:376 10th 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 = 6,500 ft2
Impervious Area (A) = 2,609 ft2 =40.1%
V = 0.92 x 2,609.0 x 9.3 /12
V = 1,860 ft3
Provided Storage:
Area 1 - FRONT Area Storage Sideslope:4 :1
(ft)(ft2)(ft3)
7.8 149 BOTTOM size:X
8.5 232 TOB size:X
Area 2 - BACK Area Storage
(ft)(ft2)(ft3)
7.5 541 BOTTOM size:X
8.5 925 TOB size:X
Area 3 -Area Storage
(ft)(ft2)(ft3)
BOTTOM size:0 X 0
TOB size:0 X 0
Inground Storage:= A*d/pf
Total Storage Area at TOB (A) =1157.0 ft2
Depth to ESHWT from BOTTOM (d) =2.2 ft, default is 2.0 ft, verify onsite ESHWT
Pore Factor (pf) =0.4 default is 0.4
Inground Storage Provided =1018.2 ft3
Required Treatment Volume =1,860 ft3
Supplied Treatment Volume =1,885 ft3
133
733
0
11/8/2021
Retention 376 10TH ST calcs 12/1/2021