340 14th St W ACC23-0031 Drainage Calculations - Updated - 4-11-24Comp. By: NAME
Date: 4/10/2024
Public Works Department
City of Atlantic Beach
Permit No:
Address: 340 14th St W
Reguired 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
Where:
which is the Modified Rational Method for estimating stormwater runoff
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=
Impervious Area (A) =
V=
V=
Provided Storage: Swale 1
Swale 1 -Relative Elev.
7,140
1,500
0.92
1,070
Area
ft2
ft2 21.0%
X 1,500.0 X 9.3
ft3
Storage Sideslope: 3 :1
12
!ft)!fl2l !ft3) Swale w/ NO WALL SLOPE
0.0 0 0 BOTTOM size: 0 X 10 0.0 0 TOB size: 0 X 0
FD 1 -Relative Elev. Area Storage
!ft)!ft2) !ft3) 0.00 0 0 BOTTOM size: 0 X 0
0.00 0 TOB size: 0 X 0
FD 2 -Relative Elev. Area Storage
!ft)!ft2) !ft3) 10.25 527 481 BOTTOM size: 19.5 X 27
11.00 756 TOB size: 24 X 31.5 FD 3 -Relative Elev. Area Storage
!ft)!ft2) !ft3) 0.00 0 0 BOTTOM size: 0 X 0
0.00 0 TOB size: 0 X 0
FD 4 -Relative Elev. Area Storage
!ft)!ft2) !ft3) 0.00 0 0 BOTTOM size: 0 X 0
0.00 0 TOB size: 0 X 0
FD 4 -Relative Elev. Area Storage
!ft)!ft2) !ft3)
0.0 0 0 BOTTOM size: 0 X 0
0.0 0 TOB size: 0 X 0
lnground Storage: = A*d/pf
Total Storage Area at TOB (A) = 756.0 ft2
Depth to ESHWT from BOTTOM (d) = 2.0 ft, default is 2.0 ft, verify onsite ESHWT
Pore Factor (pf) = 0.4 default is 0.4
lnground Storage Provided = 604.8 ft3
Required Treatment Volume = 1,070 ft3
Supplied Treatment Volume = 1,086 ft3 2.5
Retention 340 14th St W 4/10/2024
ACC23-0031