376 10th St RES21-0373 Storage Calculations_ss revision 3-18-22Comp. 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) = 2,557 ft2 =39.3%
V = 0.92 x 2,557.0 x9.3/12
V = 1,823 ft3
Provided Storage:
Area 1 - FRONT Area Storage Sideslope:4 :1
(ft)(ft2) (ft
3)
7.8 149 BOTTOM size:X
8.5 232 TOB size:X
Area 2 - BACK Area Storage
(ft)(ft2) (ft
3)
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 =1,823 ft3
Supplied Treatment Volume =1,885 ft3
133
733
0
3/3/2022
Retention 376 10TH ST calcs 3/3/2022
THIS ITEM HAS BEENDIGINTALLY SIGNED BY:
5EYN2LD D 3ETE5S2N 3E
)L 3E N2 35INTED &23IES 2) THIS D2&8MENT A5E N2T &2NSIDE5ED
SIGNED AND SEALED AND THE SIGNAT85E M8ST BE 9E5I)IED
2N ANY ELE&T52NI& &23IES
By Toni Gindlesperger at 10:49 am, Mar 18, 2022