365 8th ST - REVISION RETENTION POND e
CITY OF ATLANTIC BEACH
}
800 Seminole Road
Atlantic Beach,Florida 32233
a��9 Telephone(904)247-5800
"'� :;,`,""' FAX(904)247-5845
�wilb,
REVISION REQUEST SHEET
Date: I1 2e - Received by: Resubmitted:
Permit N tmbe l`' \5 \°N\y
Original Plans Exa� . Cep-rr Project Name: lr m,s�.ld
Project Address: 5 $T�' Sr•
Contractor.__Mc Qye�y T{� �n�r�_� Contact Name: A,,,Am
Contact Phone : cJQ4 - R 1- R 1 3 -1-7-7 R-7-7 R Contact e-mail: a 1. � ..,.a„a„ 6„ •�,�Q.-. h„„
Revision/Plan Check/Permit Fee (s)Due: $ T—
Description of Proposed Revision to Existing Permit:
C-HA,JC,a C208A RF_- jn.� DpNn T 6U .rte1 ,13,FgCE
__1LC LTA4'{_,nwl 54_$TM _
Additional Increase in Building Value: $ - 0- Additional S.F. - n
Site Plan Revised: It 25 /{ Public W/U Approval:
By signing below. I (print oaFnc)_JO 4PPN w '�" pAJ4A r4 affirm that the above revision
is inclusive of the proposed changes.
1 JJ '4z I-,] �� Ate E
Sigitatureof Contractor/Agent(Comnradorntua�;rgn Uicr in v4ualio Dat D
Oaice Use ON 2b el.115—
Date: IZ troveJ: Rejected: _ Noifi avy:
Plan Review Comments:
Department review required Yes No
Building
Planning &Zoning
Tree Administrator ns examiner
Public Works
Public Utilities _ / —
Public Safety _
Fire Services Date
252 Otterwood Ct
Jacksonville, FL 32225
Mr Doug Layton
Mr Scott Williams
Department of Public Works
City of Atlantic Beach
1200 Sandpiper Lane
Atlantic Beach, FL 32233
Re: Stormwater Management System
365 8th Street,Atlantic Beach
Dear Doug and Scott:
Enclosed is our Revision Request Sheet to permit installation of a subsurface Stormwater
Management System at the above referenced residential lot. The original plan was for a
retention pond but the ownerhas opted for the system described herein for reasons of public
health and enjoyment of their limited backyard.
The Plan reflects the several discussions we have had over the past few weeks. It is
considerably simpler than any of the conceptual plans I showed you as well as distributing
stormwater falling on the site more broadly around the site. I am confident that it will handle
almost any foreseeable precipitation event.
Thanks for the patience you've shown in helping me get up to speed on this issue. Please
contact me should you have any questions or comments on the enclosed.
Very truly yours,
Joseph W Sheahan
Consulting Hydrogeologist
Encl
Cc: Adam Smythers (w/encl)
Ed Hebert (w/encl)
365 8th LTR 112415a.Dol
11/24/15 22:27
SPECIFICATIONS
STORMWATER MANAGEMENT SYSTEM
365 B'b Street
Atlantic Beach, FL
November 24, 2015
BACKGROUND
The City of Atlantic Beach requires that stormwater falling on sites of new construction must be
managed on site, i.e., ideally no stormwater from the site will discharge to the city's storm
sewers.
The architect of the house under construction at the site has calculated that the rain event
specified by the city could produce 2,155 cubic feet (ft) or 16,371 gallons of stormwater; this
becomes the storage volume required by the city. The conventional approach - stormwater
retention basins - entails several drawbacks including serving as mosquito breeding grounds,
undesirable from a public health perspective.
SYSTEM CAPACITY
The design objective was to find 2,155 ft' of stormwater storage space in some combination of
subsurface piping volume plus the pore space in the lower 3.5 feet of unsaturated soils
underlying the site. The approach taken is to use slotted corrugated pipe to distribute the
stormwater to the unsaturated soils. The site was divided into four areas for the analysis. The
attached spreadsheet presents the calculations of storage volumes for different pipe sizes in
each area. The cells stippled and shaded blue contain the options selected to attain the
required volume with 4°% excess capacity. The Proposed Layout, Stormwater Management
System shows the system configuration based on the spreadsheet and input from the drainage
contractor.
The calculations probably merit some explanation. 1 divided the site into four areas, North, East,
South and West. The North Area is the backyard where the Retention Pond was to go. The East
Side is a narrow strip between the new house and the adjacent lot. The South Area is now a
courtyard and the front yard of the property; tiles were installed in this areas before the
courtyard walls were poured to handle downspout Flow. Finally, the West Area is the driveway
serving a side-load garage on the ground level; the driveway is being finished with pervious
pavers.
365 specifications 112415b.Uocx 1
11/20/15 21:52
The city recognizes the capacity of the pore space in the unsaturated soils (i.e., above the water
table) to hold stormwater. In calculating the site-specific available pore volume, the city
assumes a soil porosity of 30% and a watertable elevation of 3.0 feet. These parameters are
incorporated in the spreadsheet.
The first column shows the minimum length of slotted pipe to be installed in a given area..The
south and east sides have two relatively closely spaced slotted pipes each. The second column
shows that, due to the pipes' proximity, each side is assumed to have an infiltration area only
two feet wide, or one foot per tile. As we discussed, each pipe actually discharges to a
considerably wider area. The second column shows that the three tiles spaced on four-foot
centers in the wider North and West Areas, discharge to an area 12 feet wide, consistent with
the plan with which you had at one time concurred for the North Side. Both of these areas
have considerably greater areas and volumes to handle any infiltrating water.
In all cases, I have assumed a conservative 3.5 feet of unsaturated soils beneath the pipes to
absorb the infiltrating waters. These values are combined with the City's default value of 30%
porosity to yield the total unsaturated pore volumes calculated in the Column titled 30%
Volume,ft'. As shown at the bottom of that column, the unsaturated soils can hold 2,098 ft3 of
the 2,155 ft' required
The next section of the spreadsheet calculates the volumes of the lengths of pipe specified in
Column 1 for various pipe diameters to permit optimization of the system design. Six-inch
corrugated, slotted HDPE pipe was chosen for all four areas, yielding an additional 138 ft' of
storage volume. The total volume in the system so designed is 2,336 ft3, or 4% more than
required.
SYSTEM DESIGN
The infiltration system is designed to serve a purpose completely opposite from most piping
systems. Typical gravity piping systems are designed to convey liquids from Point A to Point B,
as efficiently as possible with no loss of the contents of the system. An infiltration system,
conversely, is designed to allow all of its contents to leak out and prevent discharges from the
end of the system.
The infiltration system will be installed with all pipe inverts on the north, south and east sides
set at an elevation of 6.5 ft., or 3.5 feet above the assumed water table, i.e., 1.0 foot below the
final site grade of 7.5 ft. (NAVD88). The tiles under the drive on the west side of the property
will be set at an invert elevation of 6.3 ft to accommodate the overlying pervious pavers. Cross
365 specifications 112415oDoa 2
11/24/15 21:52
section A - A' shows the placement of the tiles under the drive relative to the fill placed to bed
the pavers.
The infiltration gallery will end at an overflow outlet box which is designed to prevent water
from seeping to the surface should the infiltration gallery ever become overloaded. The invert
of the discharge from the overflow structure will be set at an elevation of 7.0 ft, i.e., at the top
of the inside of the 6" corrugated pipe in the infiltration gallery at its far extent. The overflow
structure will gravity drain to an overflow discharge adjacent to the driveway and behind the
sidewalk.
Prepared by:
Joseph W. Sheahan
Consulting Hydrogeologist
365 Specifications 112415b.Docx 3
11/24/15 21:52
' ao
s
i <
f
s
w
O i m N m r
f " o
m
C W
WT d m N
• a
a w e s E
i
n g ? GO
3 M
c d oY
O
� x
� Sa :
-
a o
� a
o -
�' zo r
w i
- � Y
a6
p 0 _
0
a
'E o
'a r
a N �
a ao i O o
p a > p o
= Y a _. O LL
a N ? + a aw
m v s 2 c
o �
C 0 a a =- h
.R-- f
q
No o y o°Do
LL CE m > p
a
Z S p c m ?
W u O r r p l
N o w >
a ^ O z
W m o 3 v
U w a y m u
�J Q 0 pNp .n �p V
V1
Q W 0
J F— QJ N = r
L
Q ++ N Q y
Lu
N
VI l
O LnLn E a s
o a > o a v I a
spa d f/f M Z a $ d
v a ?
m r
m Y Lr! \
o � �
0 ..
J D �
lV
S � u
u
�J1 r1i �
r' M
`[ I w
J
LL
cLU
fp
Ul
Z a Q Q T =
UL z
Q ami ro
O W o Ll
M -
--.3sa C ? F. F- L1 N GJ
Z . x W N N O
W N i w
V) CC 0
ai
0 O a y a
D
� > a O
�V V c% � z a M
j
� I x
` Q
1
I
qj tutu
N N
tj¢ e
Li
>
3
N
x
n
C
- - , e
-579
T.rA, «..a-.a K s .,y
C� / 6076
36 70 FRe o f PPE !o Eck. o
42
S L1a li„
Comp. By: SRW
J
'- Date: 11/20/2015
J'S19/
Public Works Department
City of Atlantic Beach
Permit No:
Address: 365 8th Street
Required Storage Volume
Criteria:
Section 24-66 of the City of Atlantic Beach's Zoning,Subdivision,and Land Development Regulations
requires that the difference bely een the pre-and posldevelopmenl volume of stonnwawler 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 feel
R=25-yr/24-hr rainfall depth(9.3-inches for Atlantic Beach)
Predevelopment Runoff Volume:
Lot Area(A) = 10,816 ft'
Runoff Coefficient
Area Lot Area
Description (fte) (ft) C. Wtd "C"
Impervious 1,777 10,816 1.00 0.16
Pervious 9,039 10,816 0.20 0.17
Runoff Coefficient(C)= 0.33
Runoff Volume
V= 0.33 x 10,816 x 9.3 I 12
V= 2,778 ft'
Postdeveloumenl Runoff Volume:
Lot Area(A) = 10,816 ft'
Runoff Coefficient
Area Lot Area
Descrip8on ffex) (flr) "C" VM"C"
Impervious s, 10,816 1.00 0.49 %ISA= 48.6%
Pervious 5,564 10,816 0.20 0.10
Runoff Coefficient(C)= 0.59
Runoff Volume
V= 0.59 x 10,816 x 9.3 1 12
V= 4,933 ft'
Reauired Stomps Volume
DV= Posldevelopment Runoff Volume-Predevelopmenl Runoff Volume
DV= 4,933 - 2,778
DV= 2,155 its
Retention 8th Stmet865 11)20MI5
s�Lv>�
Comp. By: SRW
Date: 11/20/2015
•a 91'
Public Works Department
City of Atlantic Beach
Permit No:
Address: 365 8th Street
Provided Storage:
Elevation Area Storage
0 BOTTOM
0 TOB
Elevation Area Storage
(ft) (ft') (ft')
0 BOTTOM
0 TOB
Elevation Area Storage
(ft) (k') (ft')
0 BOTTOM
0 TOB
Inground storage=A'd'pf
A=Area= 0.0
d=depth to ESHVPT=
pf=pore factor= 0.3
Inground Storage= 0.0 ft3 Required Treatment Volume= 2,155 ft3 .F73
Supplied Treatment Volume= 0 ft'
V
RetenWn Stn Street365 11/20/2015
SPECIFICATIONS qi,J1. P
/RESIDENTIAL SITE DRAINAGE SYSTEM /
3LOg`"Street pi
Atlantic Beach, FL { I I t
wBACKGROUND
The City of Atlantic Beach stipulates that stormwater falling on sites of new construction must
be managed on site, i.e., ideally no stormwater from the site will discharge to the city's storm
sewers.
The architect of the house under construction at the site has calculated that the specified rain
event could produce 2,155 cubic feet (ft3) or 16,371 gallons of stormwater. The city requires
that the site be able to retain that much water. The conventional approach - stormwater
retention basins - entail several drawbacks including serving as mosquito breeding grounds,
undesirable from a public health perspective.
SYSTEM CAPACITY
SYSTEM DESIGN
The city appropriately recognizes the ability of the pore space in the unsaturated soils (above
the water table) to hold stormwater. In calculating the site-specific available pore volume, the
city assumes a soil porosity of 30% and a depth-to-water of 3.0 feet.
The infiltration system is designed to serve a completely opposite purpose from most piping
systems. Typical gravity piping systems are designed to convey liquids from Point A to Point B,
as efficiently as possible with no loss of the contents of the system. In an infiltration system,
ideally all of the contents leak out before they can discharge from the end of the system.
The infiltration system will be installed with all pipe inverts set at an elevation of 6.5 ft., or 2.0
feet above the assumed depth of the water table in the rear(north end)of the site, i.e., 1.0 foot
below the final site grade of 7.5 ft. at the north end of the site.
The infiltration gallery will end at an overflow structure which will prevent water from seeping
to the surface should the infiltration gallery ever become overloaded. The invert of the
discharge from the overflow structure will be set at an elevation of 7.0 ft, the top of the inside
of the 6" corrugated pipe in the infiltration gallery at its distal extent. The overflow structure
635 Specifications 110315a.Docx
11/3/15 0&16
n
0
I I
n
0
1 0 V p o 41
T
a �
I � 0
N
I N fP
n �
o I
I �
I I
n
0
G a
f y]
u
will be piped to a catch basin in 8t" Street at Sta 7+37. The overflow pipe will be connected
directly to the catch basin below grade.
635 Specifications 110315a.00v
11/3/15 08:16
&' i V C
It : dY iviiyi
3 � dI�� m'5 P1,
8 m °
r m o
- GC&&" tom
m
ISI
„ o
S? an
- u °
� o
a � N
x �
6
`1` ►a
v99 q_3
�L $ 3 '
ut 3 v n nn
w v
m �
x
s
0
w z
c
wo
gm
� N
c
a ^
N
n n
N
N uZ b 0
G �
2
o � x
w � g
3 ;
3 m
� v
c w o
n y o z
-zi z o
a v 3 0
nn
N � N
i
0
n a �
U
x � _
rn
� J
n
N D — W
o J C
Z ' - \f _ 2
a ,crj
h
I n�
I
1
m 3 a n n a
� o O
_ C m
. O
s
a m F
x g
n
x , s
3
u m i
w c
g s $
m
i WSW
3 � A
W 3
z �
e w N 3
m a .
m
D
- < y
N
— O
o m O
s �
O
N
� O
O
c <
x 3 3
3 N m 3
o n JIB m
3
P n o
m o o m w r w
Z
D ^'
S
m
W �
3 " cm
'n m �
n
z
6
0
n <
n n o
1 c
n N 3 a
0
c G m
� z
z
3
< s9
d ^a O
O d R T
� O
N
O
3
3 ° i
� O
n
p n o
D ^I
q n3 a
F q e q
� I .ai\G Y •
rrta Ltir /
w\\\t t
III NINA
_ .�CydiY/\\/1S�\iSSi�e/tYSi.
/S rrrJiAA r r / /
ON
y`whaeN .w'\
weNett\t\.\\t
/iAiriir vii / s
FrA
'IIr IIIIf NI 3III
'H/ JIII AAA//. r6lr - ;•
aY\hS\\ey\wY otew.w
rtwtYSNN�a>Y.-YNN\ \
• ,� \rtr\YL�LLre1/�\LF�.(IIe/\',,II!�'�
•IHIIIII •^
I`IYI\II�I`Js°1°!✓ IiI`11•°iYii '
II/IAIN IIA IIIIIA//
q`.eheNN4t\WNNNR
•IOIlIIAAY'r OJ aIIIIIFIC.
NINE/i•!h'N•dI)'
FhwY\.W.Ntv,\�r
I/NIs�.'hVIII y,
N• a\\
;I Ie YI
II�IINII S
. w eN\Ntw.
NAAIIAII II ,
\tk1\)\A\I�\t�
A\7
�D
Comp. By: RLC
Date: 9/16/2014
Public Works Department yf l
City of Atlantic Beach /
Permit No: 13-tbd
Address: 365 STH STREET
Required Storage Volume
Criteria:
Section 24-08 of the City of Atlantic Beach's Ztxung,Subdivsim,and Land Development Regulations
requires that the difference between the pre-and postdavelopmem volume of starmwawter 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) - 10,816 ft2
Runoff Coefficient
Area Lot Area
Description (ft') (R) "C' Wtrl"C"
Impervious 1,777 10,816 1.00 0.18
Pervious 9,039 10,816 0.20 0.17
Runoff Coefficient(C)= 0.33
Runoff Volume
V= 0.33 x 10.816 x 9.3 1 12
V= 2,778 ft'
Postdeveloomern Runoff Volume:
Lot Area(A) = 10,816 ft2
Runoff Coefficient
Area Lot Area
Description (ft') (ft') "C" Wtd"C"
Impervious 5,252 10,816 1.00 0.49
Pervious 5,564 10,816 0.20 0.10
Runoff Coefftclenl(C)= 0.59
Runoff Volume
V= 0.59 x 10,816 x 9.3 1 12
V= 4,933 ft,
Reaulned Storage Volume
DV= Postdevelopment Runoff Volume-Predevelopment Runoff Volume
DV= 4,933 - 2.778
DV= 2,155 fte
Retention 1402 Repuhetl Stora9a Volume 9116/2o14
Comp. By: RLC
Date: 9/16/2014
Public Works Department
City of Atlantic Beach
Permit No: 13-lbd
Address: 365 8TH STREET
Provided Storage:
Elevation Area Storage
(ft) (ft) (11)
0.0 754 0 BOTTOM
0.5 1,303 514 TOB
Elevation Area Storage
(ft) (ft2) (ft)
0.0 268 0 BOTTOM
0.2 1,036 136 TOB
Elevation Area Storage
(ft) (ft ) (fill
0.0 0 0 BOTTOM
0.5 0 0 Toa
Inground storage-Mtrpf
A=Area- 2339.0
d=depth to ESHWr= 3.0
pf=pore factor= 0.3
Inground Storage= 2105.1 ft°
Required Treatment Volume= 2,155 ft2
Supplied Treatment Volume a 2,755 ft2
�J\S
rr'
a.wvw .2_9e9WrW%iv Vdum. 911eWla
s
I' l W7
W W N
N
V -qp J
fZ
O
� U � O Z
D
3 C u
p � L
Q J eul P W w T
O N d
M �
N d
a. �n
u �
n �
�b
i
{ J QIQ