382 7TH ST PW COMMENTS CITY OF ATLANTIC BEACH
DEPARTNIENT OF PUBLIC WORKS
1200 Sandpiper Lane
Atlantic Beach,Fl, 32233-4318
TELEPHONE:(904)247-5834
FAX:(904)247-5843
www.coab.us
October 15, 2014
Collins Builders Group
3870 Crown Point Road STE C
Jacksonville, FL 32257
Fax: 904-268-2412
Subject: 382 - 7th Street
Atlantic Beach
Permit no. 14-1212
Gentlemen:
We have reviewed the referenced permit and offer the following. The Swale in the SE comer of
the lot may be adjusted as follows.
Top of berm elevation: 7.5' (7' minimum)
Elevation of Swale at SE lot comer: 5.5'
Average elevation of Swale: 6'
These changes are optional, and may be implemented at the owner's discretion for ease of future
maintenance. You may consider this a modification to the subject construction permit.
Please maintain this letter and the attachment onsite as part of your permit.
City of Atlantic Beach,
Douglas E. Layton,PE
Director of Public Works
Attachment: Revised stormwater volume calculations dated 10/14/14
MMft;,O ell,
Comp. By: DEL
Date: 10/14/2014
Public Works Department
City of Atlantic Beach
Permit No: 14-1212
Address: 382 7th St
Required Storage Volume
Criteria:
Section 24-66 of the City of Atlantic Beach's Zoning, Subdivsion, and Land Development Regulations
requires that the difference between the pre-and postdevelopment volume of stormwawter runoff be
stored on site. Volume of Runoff is defined as follows:
V= CAR/12
Where: V=Volume of Runoff
C=Coefficient of Runoff
A=Area of lot in square feet
R=25-yr/24-hr rainfall depth(9.3-inches for Atlantic Beach)
Predevelopment Runoff Volume:
Lot Area(A) =
Runoff Coefficient
Area Lot Area
Description (ft) (ft) Wtd "C"
Impervious 2,535 15,026 1.00 0.17 From PA Records
Pervious 12,491 15,026 0.20 0.17_
Runoff Coefficient(C) 0.33
Runoff Volume
V= 0.33 x 15,026 x 9.3 12
V= 3,901 ft3
Postdevelopment Runoff Volume:
Lot Area(A) = 15,026 ft2
Runoff Coefficient
Area Lot Area
Description (ft) (ft) VWd "C"_%1SA 49.6%
Impervious 7,459 15,026 1.00 0.50
Pervious 7,568 15,026 0.20 0.10
Runoff Coefficient(C) 0.60
Runoff Volume
V= 0.60 x 15,026 x 9.3 12
V= 6,953 ft3
Required Storage Volume
DV= Postdevelopment Runoff Volume- Predevelopment Runoff Volume
DV= 6,953 3,901
DV= 3,053 W
Retention 382 7th st-onsite Retention w-grnd DEL 10/14/2014
Comp. By: DEL
Date: 10/14/2014
Public Works Department
City of Atlantic Beach
Permit No: 14-1212
Address: 382 7th St
Provi led Storage:
Elevation Area Storage
F 2 3
( ft (ft
6.0 0 0 BOTTOM
7.0 2,500 1,250 TOB
Elevation Area Storage
Fftl� (ft 2 (ft 3
0.0 0 0 BOTTOM
0.0 0 0 TOB
Elevation Area Storage
ftl ft2 (ft 3) —
0.0 0 0 BOTTOM
0.5 0 0 TOB
Inground storage=A*d*pf
A=Area= 2500.0
d=depth to ESHWT= 3.0
pf=pore factor= 0.3 ft3
Inground Storage= 2250.0
Required Treatment Volume= 3,053 ft3
Supplied Treatment Volume= 3,500 ft3
Retention 382 7th st-onsite Retention w-grnd DEL 10/14/2014
0
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