20120399 Ver 1_More Info Received_20120813

SGI Technical Services
200 North Greensboro Street, Suite B -13A
Carrboro, NC 27510
phone: [phone]
email:[e-mail]
(# C -2092)
9 August 2012
Wetlands, Buffers, Stormwater Compliance and Permitting Unit
NCDENR/Division of Water Quality — Wetlands and Stormwater ranch
1650 Mail Service Center
Raleigh, NC 27699 -1650
Attn: Ms. Amy Chapman
Ms. Karen Higgins
@���
D
AUG132012
DENR . WATER QUALITY
Reference: Riverwinds Condominiums, Blackwell Point Loop Rd, Oriental, NC
Smith Creek
DWQ Project #2012 -0399
Dear Ms. Chapman:
Enclosed is the requested information concerning the proposed buffer mitigation at
the Riverwinds Condominiums, Blackwell Loop Rd, Oriental, NC. The attachments include: (1)
a drawing of the existing conditions on the property that also shows the proposed decks; (2)
a copy of the stormwater management plan showing the location and specifications for the
proposed bio- retention garden; (3) a copy of the sizing calculations for the bio- retention
garden; (4) a suggested maintenance agreement; and (5) a CD on which .pdf files of the
aforementioned information have been stored. Please note that a letter from your office
requested that the stormwater management plan be in black &white. The paper copy that is
enclosed is in color, however, a b &w copy is included on the CD.
As discussed in our telephone conversation, Riverwinds is required to reduce
Nitrogen concentration by 30% in runoff from 431 -sf impervious surface in order to satisfy
1
buffer mitigation requirements. To that end, Riverwinds has opted to construct a bio- retention
garden with 3 -ft planting soil, 12° ponding zone and an underdrain, to treat the first inch of
runoff from the designated impervious area. The proposed garden location in the common
area of the site and the garden design are shown on the attached stormwater management
plan.
SGI

The impervious surface that will be drained to the bio- retention garden is a section of
the roof on Unit -1 of the condominiums. A roof gutter from this area will be re- routed to
discharge directly to the bio- garden in an open- bottom, concrete planter. The area of the
selected roof section is 655.5 -sf, which is larger than the impervious drainage area required
to satisfy the mitigation requirements. To accommodate the increased runoff volume, the
proposed bio- retention garden will be larger than required, 52 -sf rather than 34 -sf. The
proposed bio- retention garden will be a 4'x13'x4.25' (hgt.) open -bottom planter, installed
partially sub -grade on a 12" stone base with an underdrain pipe system. This style and
configuration are proposed due to the limited construction space available on the property
and because the native soils exhibit poor infiltration characteristics (Group C). Sizing was
calculated using the Simple Method.
A suggested Operations and Maintenance agreement is also attached. This is based
on agreements we have written in the past and it is enclosed for your review and comment.
Please advise as to content, disposition and required procedures.
If there are any questions or comments or if additional information is necessary,
please do not hesitate to contact SGI Technical Services at (919) 942 -7612 (office) or (919)
418 -5587 (mobile).
Sincerely,
SGI Technical
Steven A. Addy, PE
2
SGI

O)
C
�N
U)
c
GO
m
D!
C
O
M
C
Y
LP
a
Y
V
'O
d
2
U U U U U
m m m m m
0000 Cl)
0 0 0 0 O
m OOCLo 0
M
m V'
m
U
C
W N
m
U U U U U
m m m m m
0000 O M
0 6 6 0 O
Ln O O Ln O
N Lr?
�n O in
I CD rl N
m �
N
U
C
(AN
N m
Ln W
cc
c c
�cc
CD
m
vv
N
C N
O
m
�e m
= E
0) m
C CL a�
o
rn
o
CL n
m j j c
m
CL
-0 _0
V m.
n n v v`
_
N m
.-
c
a�
L
y
C N
� d
m
N
U
m
U
L m
U
C
y
U U U U U
m m m m m
0000 O M
0 6 6 0 O
Ln O O Ln O
N Lr?
�n O in
I CD rl N
m �
N
U
C
(AN
N m
Ln W
cc
4) CD
N
cm
N
d
u
_
O
E
� L
m
c_
rn
o
v a
v
n
N Ln
a i `
cn
-
Om _ "O 'O
E
L
U
-o
m
L
y
C N
� d
rn
U
C
N
U
3
U
L m
y
y
C
N
N
O
N
M
u Z
E
3 N
w O
c E
O
N
u
TL
N
c
U
U
U
C
�
y,
N N
Q—
T
,dma°DO
°>
N w
m
07
oro m
O a0 m
3 2
oo;
n a
n o
n n
n n n n
n n n n
v d a
CD
3 2
m
°O
—
rn
—
a m
O
o
a
o
Ln
�
o
O
C5
d
d
>
c
a
O
�
3
^>
a
z
3
w
Y
U
W
Y
U
Y
N
Y
N
U
�
N
2
U
O
N
2
2
2
U U U U U
m m m m m
0000 O M
0 6 6 0 O
Ln O O Ln O
N Lr?
�n O in
I CD rl N
m �
N
U
C
(AN
N m
Ln W
N
U O
D N
CM
N
— V1
7
Q
cc
4) CD
N
N
cm
N
d
U
Y m
c a
E
� L
m
c
Cl
rn
o
v a
>
O ._ m
t M
-
Om _ "O 'O
E
N M
c
a�
-o
m
N
y
C N
� N
rn
U
C
N
U O
D N
CM
N
— V1
7
Q
N
N
U
_
O
c
co
d
t M
N
y
C N
� N
L m
y
O
v.Z
E
3 m
w
C E
d
` .
TL
~
C
U C
U
C
7
L
m d
C
6 —_
�
N�
N OD ID
O am+
°'v.rnc
M a0
R C
O a0 m
3 2
oo;
n n
n o
n n
d a
n n n n
v d a
3 2
m
°O
—
a m
o
Ln
_
'
>
O
C5
a
d
>
a
�
3
W
w
Y
U
Y
U
N
N
2
2
N
U O
D N
CM
N
— V1
7
Q

BIOGARDEN draw
roof, pavement
area (ac) 0.018
composite C 0.96
CN 98
P (in) 1
runoff
S 0.00
runoff (in) 1.00
volume (ac -in) 0.00
volume (sf -in) 0
bio-garden depth (in) 9.0
SA (sf) 0
bio-garden depth (in) 12.0
SA (sf) 52
determine underdrain size and drawdown times
planting soil depth (ft) 3.0
soil permeability (in/hr) 1.5
determine draw through rate
Q (cfs) 0.002
K (in/hr) 1.5
A (sf) 52
dH 4.00
dL 3.00
time to draw from inundation
to saturation at surface
treatment area (sf) 52
depth (ft) 1.0
drawdown rate (cfs) 0.002
V (I-S) (cf) 52
T (I-S) (sec) 21739
T (I -S) (hrs) 6.0
time to draw from saturation
at surface to 2' below surface
soil porosity (n) 0.45
treatment area (sf) 52
�me to be removed from 2 -ft 47
drawdown rate (cfs) 0.002
T(S-2) 19565
T (S -2) 5.4
DRAWDOWN TIME (hrs) 11.5
time
SIZING N *D= 16 *(Q *n /(SA0.5))A.375
Q (cfs) 0.002
10 *Q (cfs) 0.02
n 0.013
s 0.005
N *D 0.88
Hedrick Bio- retention garden sizing
drawdown rate and undercirsin sizing
SGI Tech
Soil group C
DESIGN STORM
S= (1000 /CN -10)
P= ((P- 0.2 *S)A2) /(P +0.8 *S)
required surface area 9" ponding
VEGETATION COVER - plants, shrubs
sandy loam (85 -88% sand;8 -12% silt +clay;3 -5% organics)
(2.3E- 5) *K *A *(dH /dL)
hydraulic conductivity of soil
surface area of bio- retention area
height of water above gravel envelope /drainage pipe zone
thickness of soil
volume
time
time
porosity percent
volume
Sec
hrs
total
fos
Manning
0.5%
inches use 4" slotted pipe

CONTACT the National "Call Before You Dig" 811 to have underground facilities located
before beqinninq any excavation.
normal water line \ sub -drain
- outlet 96'
7. 5' \ w. anti - seepage 4'x13'x4.25' (hgt.) bio- garden planter
5l ______________________________ stone dissipator 6" PVC
° invert out 95.8' collar (open bottom, concrete block)
S 86 0445' W 190.16' s (min) 0.5%
- - - - - -- ------ •• - - - - -- bulkhead -------------------------
- - - - -- \ \ � total 61 -sf ponding area @ 12" depth note: possible re- location
-----------
- - - - - -- - --
\ == surface of planting soil at of underground
\ \ \ \ trellis " " "" -- -- - - - - -- elevation 100 (or higher) electrical supply
Il\ \ - -� - - - --
_ - - - - -- __ d - - - __ - ----- -
--bulk head - - - --
f
- - -- 8- ftsetba ck_ _ _L - - - - - - --
a
fs
co ---- - - - -_
----- -2.5 -ft •___ � I
\ \\ \ \ ---- --- - -'`�� ____- - - -8 -ft setback-
6-1 - - -- bulkhead------- -------- - - - - -- conc.
\ 10.0r 2' clearance - -- - - -- --- - - - - --
\ 55. - c lift I /
\ \ \ \mo `ACi col ' I , - T station
o U I /
\ \ \ 7 i f elec- _ _SS I
\ \ I\ TBM= 100.00 ss M1 overflow
\ \ \ I o° 4" PVC I - - 7 -UG elec - -
\ \ N L roof -- -stone underdrain
"' N \ UNIT 1 \ dissipator I W
\ drainage area I � �
\ i \ to bio garden roof - gutter /I
\ \ I •\
proposed '�\ '\ 655.5 -sf (23'x28.5') � outlet to
\ _ \ deck � \ I bio - garden O I
\ \ t \ \ establish c'
"Private Reserved Storm Drainageway Easement " /
\ - - - - - parameters to be designated :D
\ \ 1 \ 10.00' \ - -W - - -- - ( - - - -_ -)
\ \,\ 55.22 UG elec _ _ W= 1G eTec�+
\ \ (P I \ - -0 SS -
\ - -SS- ` - I
Cn
o \ \ N I
ncrete driveway
\ \ \ I \ N N \ \ I I
\ \\ I \ N \ UNIT 2 I I
w
\ \ \\ I \ proposed \ \ I I I concrete driveway
\ \ \ \\ I \ deck `\ \\ I w � ® I ^ o
\\ \ I I o 0
W
a,
:D
LOT 3
\ \\ \\ II \ \ on i 1
u
1
BIO- RETENTION BASIN
Bio- retention Basin Construction
1. OwnerAnstaller must verify that water table is at least 2 -ft below base of drainage layer.
2. Interior slopes around interior perimeter shall not exceed 3:1.
3. Unless indicated, no artificial conduits should intercept bottom or sidewalls of basin.
4. Prior to site grading, a sediment fence should be placed around the area that will be disturbed
5. Prior to excavation of the bioretention pit, a sediment fence should be placed around the basin area
6. Planting soil should consist of 85 % -88% sand (washed, medium), 8 % -12% fines (clay &silt), 3 % -5% organic matter; it
should have infiltration rate 1 "-2" per hour, and a P -index between 10 -30. Planting soils shall be of uniform composition
and contain no deleterious materials. Written approvaVicertification by a soil specialist will be required.
7. Planting soil shall be placed in lifts of 12 -18- inches without compaction. Installer should overfill to approximately 2 -in. above proposed
design elevation to allow for settlement. Planting soil surface should be level with no low areas.
8. Mulch layer shall consist of double or triple shredded hardwood mulch that is free of weed, seeds, soil, roots, or any substance not
consisting of bole or branch wood and bark. Mulch shall be shall be aged at least 12- months prior to placement and applied in a
uniform layer 2 -in to 4 -in depth. Mulch layer should be inspected after each rainfall event and repaired whenever necessary. A written
record of inspections, maintenance and repairs should be kept by owner.
9. Surface of planting soil should be level with no low areas.
10. Landscape and planting plan is shown on sheet C -2.
11. The underdrain discharge pipe shall be 4 -in diameter, sch 40 PVC, slotted or perforated installed as inidcated;
discharge outlet is 6 " -d; ends of cleanout pipe(s) shall be capped at grade for secondary use as liquid level monitors. Install cleanout
(4" min) at end of each pipe run and at all directional changes. Cleanouts should terminate greater than 12 -in above garden surface.
12. Underdrain layer shall be separated from planting soil and native soil using Filterweave 400 or approved equivalent. Filter fabric shall
have minimum permittivity 75 gal /min /sf
13. A stone dissipator should be installed at roof drain pipe outlet into planter and at underdrain outlet.
14. Sequece installation of sediment and erosion controls to minimize the contamination of the planting soil with silts and fines. Sediment
controls must be installed around the area to be disturbed before grading, and around the bioretention area before the excavation of
the trench or pit for the planting soil.
MISCLELLANEOUS NOTES:
1. The specific surface area indicated for the bio- retention garden describes the minimum level surface required.
3. Cleanouts shall be at least 4" diameter and terminate with caps greater than 12 -in above planting soil surface.
4. Elevations of bio- garden /detention components may be adjusted due to field conditions, however, it is important that relative elevations
and sizes remain consistant between different parts of the system. All changes must be pre- approved.
Bioretention Basin Construction & Planting Sequence
During construction, protect future bio- garden areas from sediment intrusion unless indicated otherwise. Bio - garden shall not be
constructed until after completion of activities that could impact future performance. All disturbed surfaces must be stabilized within
15 -days of disturbance. Biogarden uses 3 -ft planting soil and shall be mulched and planted.
Bioretention Area General Maintenance
1. Visually inspect soil monthly. Repair damage caused by erosion, etc.
2. Remove void areas in organic layer whenever necessary and add additional mulch where needed at least once per year in the spring.
3. Remove and replace all dead and /or diseased vegetation that is beyond treatment twice per year during the periods from 3/15 to 4/30
and from 10 /1 to 11/30.
4. Treat all diseased trees and shrubs whenever signs of disease or insect infestation are observed.
5. After completion of planting, water plant material; water regularly at the end of each day for 14 consecutive days.
6. Replace deficient stakes or wires whenever needed.
7. Remove support stakes and wires at the end of the first year.
8. Maintain written record of all inspections and maintenance.
9. For additional information, consult NCDENR BMP manual and maintenance agreement documents.
Stormwater System Maintenance
1. Monthly and after each rainfall event (especially in fall), check inlet /outlet paths to make sure they are free of debris, leaves and any
other deleterious materials that could restrict flow or infiltration of surface water.
2. Monthly and after each event, verify that inlet /outlet /overflow pipes are not blocked by debris and are free to flow.
13110-RETENTION PLANTER PROFILE
(no scale)
planter- 4'x13'x4.25' (hgt.)
6" overflow riser
12" above soil
2.5' clearance to bldg.
ex. grade 99.8'
12" ponding
planting soil 100'
w. 2 -3" hardwood
mulch layer
top of planter wall 101.25'
- clean -out ex. grade 99.1'
)ossible future
? -in overflow slot for future expansion
nvert at 9 -in above planting soil
possible planter expansion
10 - - - - -- - - - - - -- - -- - -- - -- ----------------------------- - - - - -- - - --
100 111111111111111L - -- - - - -3 depth - - -- 1 -------------------------
in. around perimeter------------------ ------
- - planting soil--- -
cut -off to � - -- J
protect Y I I I I I I 1777�� -
bldg. foundation - -
-----------------------------------------
95 -- - - -- -------- - - - - -- - - - - - -- - - - - - -- ------------------------------------------
6" PVC line out
slope min 0.5%
invert 96'
install clean -out
at upper end filter fabric layers between
anti - seepage collar sand and stone, stone and native
12 -in #57 drainage layer soil- use Filterweave 400
with 4" slotted /perforated or approved equivalent
pipes - PVC sch 40 all filter fabric shall have minimum
NOTE:
CONTRACTOR SHOULD INSTALL TO KEEP SURFACE ELEVATION OF PLANTING SOIL AT OR BELOW SURFACE ELEVATION OF EXTERIOR SOIL
ALLOW AT LEAST 2.5 -ft CLEARANCE TO FOOTING
end of FES
(flared end section)
k
Outlet Dissipator
(no scale)
dia =Do
La +Do
FABRIC - use 8 -oz., non - woven, needle punched
1. width at pipe outlet =3 x pipe diameter (Do) (for double pipes, width is
3xDo plus center -to- center distance )
2. length beyond end of FES (La) =12 -ft minimum; increase to minimum 20 -ft at
outlet of 30" pipes
3. width at end of apron= 12 -ft +Do (pipe diameter); for double pipes add
center -to- center distance; for 30" pipe, width is 22.5 -ft
4. stone thickness =22 -in min. for Class B; for Class A: thickness =1 2 "; for
Rougemont no. 39: thickness =8"
5. underlay stone with filter fabric; all filter fabric shall have minimum permittivity
75 gal /min /sf
6. construct level surface for length and width inidcated, then provide smooth
transition to existing grade
Roof, bio-garden drains:
1. width at pipe outlet =3 x pipe d
2. length beyond end of pipe =4 -ft min.
3. width at end =3 -ft min.
4. thickness =1.5 x max. aggregate size, (0.5 -ft min.)
5. use Rougemont No. 39 stone or eq. underlain by filter fabric
G R.
SITE INFORMATION
1. Address: 236 Blackwell Point Loop Road
2. Deed Book 441, Page 671
3. Size: 0.57 -acre, common area: 0.35 -ac.
4. Soil Type: Altavista (AaA) group C
5. Flood Zone: AE
1. Deck area in Zone 2: 431 -sf
2. Minimum area of impervious surface drained to bio- retention: 431 -sf
3. Minimum required bio- retention surface area for
431 -sf impervious surface (12" ponding depth): 34 -sf (Simple Method)
4. Actual impervious drainage area to bio- retention (roof section): 655.5 -sf
5. Minimum constructed bio- retention surface area for
655.5 -sf impervious surface (12" ponding depth): 52 -sf (Simple Method)
6. Drawdown to 2 -ft below surface (3 -ft planting soil, K =1.5): -11.5 -hrs
10' 0 10' 20'
Scale 1" = 10'
2 foot contour interval (GIS)
LEGEND:
O IRON FOUND
IRON SET
0 CALC. CORNER
❑ CONC. MONU.
buffer, riparian buffer
,'443.6',
', 0 +50 ,' spot elevations - existing
`-__ -'
443.6
0 +50 spot elevations - proposed
The QUANTITY shown for each is the number of pthat type
of plant that will be planted in the garden locations indicated
on sketch below.
13'
8 8 8 $ $ $
.. nU) ra
plant locations are approximate
adjust as necessary;
evenly distribute ground cover
Bio - garden area is 52 -sf with flat surface;
provide stone dissipators at all pipe outlets
Anti - seepage Collar
(typical - no scale)
extend min. 6 -in. into undisturbed earth
extend min. 12 -in. above and below pipe
trench wall __, �12 "�
6" dia.
rain pipe
concrete anti - seepage collar
concrete - 3,000 psi
planting soil area =52 -sf with 12" ponding depth
planting soil elevation = 100'
min. 52 -sf
4'x13' surface with
12" ponding depth
garden surface elev. 100'
underdrain outlet ~96'
overflow riser at elev 101'
top of planter wall 101.25'
-- -- - - -_ CAMA line
Denotes Approx. Tree Line
Topographic and boundary information are from Pamlico Cty GIS map and drawings
by Suitt & Associates, P.A. dated May & Nov 2008 and Feb 2011 provided by land
owner. Prior to beginning field activities, contractor should verify elevations and
locations of all existing boundaries, utilities, structures, and other appurtances both
aboveground and below. It will be contractor's responsibility to report deviations from
design drawings. Contractor will be responsible for repairs to damages as well as for
site restoration.
PRELIMINARY - NOT FOR CONSTRUCTION
SGI Technical Services
200 North Greensboro Street Suite B -13A
Carrboro, NC 27510
phone: [phone] fax: [phone]
email: stevena @sgitech.net
roiect Name
DECK INSTALLATION
(variance request)
Developer /Owner /Applicant:
RIVERWINDS CONDOMINIUMS, LLC
Gwinn Hedrick
401 Vandemere Street
Oriental, NC 28571
Drawing Title
STORMWATER MANAGEMENT PLAN
Revisions:
Number Description Date
submittal 1 initial to DWQ for review 9 Aug 2012
SAA
by:
9 Aug 2012
1 of
e:
1 " =10'
I C -1
GENERAL
COMMON NAME
NO.
QUANTITY"
PLANTING
SPACING
- • • - 354- - existing contours
1. Planter design /construction by others
SIZE
2. direct designated roof outlet(s) to bio- retention basin; install stone
cn
M
dissipators at all pipe outlets
397 proposed contours
3. grade exterior perimeter of planter to encourage surface runoff to
2
drain away from sides of planter
-
(?
Cn
4. elevations shown on drawing may be modified by grader due to field
IC planting, screening
conditions; it is important to maintain elevation differentials between the
N
various parts of the stormwater structure, access to BMP, and
4
clearances to the buildings and other structures.
J
deciduous tree
5. Retaining walls, if necessary, will be by others
6. EASEMENT to be arranged between owner, surveyor and governing
N tree clearance
5
authority.
Z
T
EROSION and SEDIMENT CONTROLS
-- disturbed area
1
asp
Owner /developer must control erosion in accordance with North Carolina
w
a
` silt fence
General Statutes. Land disturbing activities shall be conducted in accordance
with requirements of NCDENR Land Quality Division and the local
Liriope muscaria
Liriope
8
Erosion Control Authority. Stabilize all disturbed surfaces within 15 -days of
4" pots
check dam
disturbance
9
STORMWATER PIPING INSTALLATION
bio - garden
1. All piping and ancillary equipment shall be purchased, stored, unloaded and
moved, installed and tested in accordance with local regulations, the NC
pp power pole
Mechanical, Building and Plumbing Codes and Manufacturer's
specifications.
FH fire hydrant
2. Installation and construction activities shall comply with OSHA requirements.
3. Manufacturer's instructions for installation, storage and maintenance of
R -o -w
drainage pipe and other construction materials are assumed part of this
o bicycle rack
35 -ft
document.
4. All gravity drainage pipe shall be sloped minimum 0.5 %; slopes around
- - - -UG elec- - - underground electric
perimeter of structures shall drain away from residential foundation at
minimum 20:1 slope for first 10 -ft.
- - - -gas- - - - gas pipe
RCP (SW)- stormwater
- - - -ss- - - - sanitary sewer
BIO- RETENTION GARDEN
water
(no- scale)
--- API - - --
R -O -W
BIO- GARDEN PLANTING INFORMATION
- -
The QUANTITY shown for each is the number of pthat type
of plant that will be planted in the garden locations indicated
on sketch below.
13'
8 8 8 $ $ $
.. nU) ra
plant locations are approximate
adjust as necessary;
evenly distribute ground cover
Bio - garden area is 52 -sf with flat surface;
provide stone dissipators at all pipe outlets
Anti - seepage Collar
(typical - no scale)
extend min. 6 -in. into undisturbed earth
extend min. 12 -in. above and below pipe
trench wall __, �12 "�
6" dia.
rain pipe
concrete anti - seepage collar
concrete - 3,000 psi
planting soil area =52 -sf with 12" ponding depth
planting soil elevation = 100'
min. 52 -sf
4'x13' surface with
12" ponding depth
garden surface elev. 100'
underdrain outlet ~96'
overflow riser at elev 101'
top of planter wall 101.25'
-- -- - - -_ CAMA line
Denotes Approx. Tree Line
Topographic and boundary information are from Pamlico Cty GIS map and drawings
by Suitt & Associates, P.A. dated May & Nov 2008 and Feb 2011 provided by land
owner. Prior to beginning field activities, contractor should verify elevations and
locations of all existing boundaries, utilities, structures, and other appurtances both
aboveground and below. It will be contractor's responsibility to report deviations from
design drawings. Contractor will be responsible for repairs to damages as well as for
site restoration.
PRELIMINARY - NOT FOR CONSTRUCTION
SGI Technical Services
200 North Greensboro Street Suite B -13A
Carrboro, NC 27510
phone: [phone] fax: [phone]
email: stevena @sgitech.net
roiect Name
DECK INSTALLATION
(variance request)
Developer /Owner /Applicant:
RIVERWINDS CONDOMINIUMS, LLC
Gwinn Hedrick
401 Vandemere Street
Oriental, NC 28571
Drawing Title
STORMWATER MANAGEMENT PLAN
Revisions:
Number Description Date
submittal 1 initial to DWQ for review 9 Aug 2012
SAA
by:
9 Aug 2012
1 of
e:
1 " =10'
I C -1
LATIN NAME
COMMON NAME
NO.
QUANTITY"
PLANTING
SPACING
SIZE
FT.
cn
M
1
D
2
Cn
3
N
4
J
a
Z
5
Z
6
w
a
7
\SSES
Liriope muscaria
Liriope
8
-36
4" pots
8 " -12"
9
The QUANTITY shown for each is the number of pthat type
of plant that will be planted in the garden locations indicated
on sketch below.
13'
8 8 8 $ $ $
.. nU) ra
plant locations are approximate
adjust as necessary;
evenly distribute ground cover
Bio - garden area is 52 -sf with flat surface;
provide stone dissipators at all pipe outlets
Anti - seepage Collar
(typical - no scale)
extend min. 6 -in. into undisturbed earth
extend min. 12 -in. above and below pipe
trench wall __, �12 "�
6" dia.
rain pipe
concrete anti - seepage collar
concrete - 3,000 psi
planting soil area =52 -sf with 12" ponding depth
planting soil elevation = 100'
min. 52 -sf
4'x13' surface with
12" ponding depth
garden surface elev. 100'
underdrain outlet ~96'
overflow riser at elev 101'
top of planter wall 101.25'
-- -- - - -_ CAMA line
Denotes Approx. Tree Line
Topographic and boundary information are from Pamlico Cty GIS map and drawings
by Suitt & Associates, P.A. dated May & Nov 2008 and Feb 2011 provided by land
owner. Prior to beginning field activities, contractor should verify elevations and
locations of all existing boundaries, utilities, structures, and other appurtances both
aboveground and below. It will be contractor's responsibility to report deviations from
design drawings. Contractor will be responsible for repairs to damages as well as for
site restoration.
PRELIMINARY - NOT FOR CONSTRUCTION
SGI Technical Services
200 North Greensboro Street Suite B -13A
Carrboro, NC 27510
phone: [phone] fax: [phone]
email: stevena @sgitech.net
roiect Name
DECK INSTALLATION
(variance request)
Developer /Owner /Applicant:
RIVERWINDS CONDOMINIUMS, LLC
Gwinn Hedrick
401 Vandemere Street
Oriental, NC 28571
Drawing Title
STORMWATER MANAGEMENT PLAN
Revisions:
Number Description Date
submittal 1 initial to DWQ for review 9 Aug 2012
SAA
by:
9 Aug 2012
1 of
e:
1 " =10'
I C -1

i
normaI water line 1
sub -drain
outlet 96'
note: possible re- location
of underground
electrical supply
�o t \1 - uv eic�- f... s
1 --- - -SS -_ 1
UNIT 2 proposed
\\ deck f
BIO- RETENTION BASIN
Bio- retention Basin Construction
1. OwnerAnstaller must verify that water table is at least 2 -ft below base of drainage layer.
2. Interior slopes around interior perimeter shall not exceed 3:1.
3. Unless indicated, no artificial conduits should intercept bottom or sidewalls of basin.
4. Prior to site grading, a sediment fence should be placed around the area that will be disturbed
5. Prior to excavation of the bioretention pit, a sediment fence should be placed around the basin area
6. Planting soil should consist of 85 % -88% sand (washed, medium), 8 % -12% fines (clay &silt), 3 % -5% organic matter; it
should have infiltration rate 1 "-2" per hour, and a P -index between 10 -30. Planting soils shall be of uniform composition
and contain no deleterious materials. Written approvaVicertification by a soil specialist will be required.
7. Planting soil shall be placed in lifts of 12 -18- inches without compaction. Installer should overfill to approximately 2 -in. above proposed
design elevation to allow for settlement. Planting soil surface should be level with no low areas.
8. Mulch layer shall consist of double or triple shredded hardwood mulch that is free of weed, seeds, soil, roots, or any substance not
consisting of bole or branch wood and bark. Mulch shall be shall be aged at least 12- months prior to placement and applied in a
uniform layer 2 -in to 4 -in depth. Mulch layer should be inspected after each rainfall event and repaired whenever necessary. A written
record of inspections, maintenance and repairs should be kept by owner.
9. Surface of planting soil should be level with no low areas.
10. Landscape and planting plan is shown on sheet C -2.
11. The underdrain discharge pipe shall be 4 -in diameter, sch 40 PVC, slotted or perforated installed as inidcated;
discharge outlet is 6 " -d; ends of cleanout pipe(s) shall be capped at grade for secondary use as liquid level monitors. Install cleanout
(4" min) at end of each pipe run and at all directional changes. Cleanouts should terminate greater than 12 -in above garden surface.
12. Underdrain layer shall be separated from planting soil and native soil using Filterweave 400 or approved equivalent. Filter fabric shall
have minimum permittivity 75 gal /min /sf
13. A stone dissipator should be installed at roof drain pipe outlet into planter and at underdrain outlet.
14. Sequece installation of sediment and erosion controls to minimize the contamination of the planting soil with silts and fines. Sediment
controls must be installed around the area to be disturbed before grading, and around the bioretention area before the excavation of
the trench or pit for the planting soil.
MISCLELLANEOUS NOTES:
1. The specific surface area indicated for the bio- retention garden describes the minimum level surface required.
3. Cleanouts shall be at least 4" diameter and terminate with caps greater than 12 -in above planting soil surface.
4. Elevations of bio- garden /detention components may be adjusted due to field conditions, however, it is important that relative elevations
and sizes remain consistant between different parts of the system. All changes must be pre- approved.
Bioretention Basin Construction & Planting Sequence
During construction, protect future bio- garden areas from sediment intrusion unless indicated otherwise. Bio - garden shall not be
constructed until after completion of activities that could impact future performance. All disturbed surfaces must be stabilized within
15 -days of disturbance. Biogarden uses 3 -ft planting soil and shall be mulched and planted.
Bioretention Area General Maintenance
1. Visually inspect soil monthly. Repair damage caused by erosion, etc.
2. Remove void areas in organic layer whenever necessary and add additional mulch where needed at least once per year in the spring.
3. Remove and replace all dead and /or diseased vegetation that is beyond treatment twice per year during the periods from 3/15 to 4/30
and from 10 /1 to 11/30.
4. Treat all diseased trees and shrubs whenever signs of disease or insect infestation are observed.
5. After completion of planting, water plant material; water regularly at the end of each day for 14 consecutive days.
6. Replace deficient stakes or wires whenever needed.
7. Remove support stakes and wires at the end of the first year.
8. Maintain written record of all inspections and maintenance.
9. For additional information, consult NCDENR BMP manual and maintenance agreement documents.
Stormwater System Maintenance
1. Monthly and after each rainfall event (especially in fall), check inlet /outlet paths to make sure they are free of debris, leaves and any
other deleterious materials that could restrict flow or infiltration of surface water.
2. Monthly and after each event, verify that inlet /outlet /overflow pipes are not blocked by debris and are free to flow.
1310- RETENTION PLANTER PROFILE
(no scale)
planter: 4'x13'x4.25' (hgt.)
6" overflow riser
12" above soil
2.5' clearance to bldg.
ex. grade 99.8'
12" ponding
planting soil 100'
w. 2 -3" hardwood
mulch layer
top of planter wall 101.25'
- clean -out ex. grade 99.1'
)ossible future
? -in overflow slot for future expansion
nvert at 9 -in above planting soil
at upper end filter fabric layers between
anti - seepage collar sand and stone, stone and native
12 -in #57 drainage layer soil; use Filterweave 400
with 4" slotted /perforated or approved equivalent
pipes - PVC sch 40 all filter fabric shall have minimum
permittivity 75 gal /min /sf
NOTE:
CONTRACTOR SHOULD INSTALL TO KEEP SURFACE ELEVATION OF PLANTING SOIL AT OR BELOW SURFACE ELEVATION OF EXTERIOR SOIL
ALLOW AT LEAST 2.5 -ft CLEARANCE TO FOOTING
end of FES
(flared end section)
(no FES on roof or
bio- garden drain outlet)
pi l
d is
Outlet Dissipator 1. width at pipe outlet =3 x pipe diameter (Do) (for double pipes, width is
(no scale) 3xDo plus center -to- center distance )
2. length beyond end of FES (La) =12 -ft minimum; increase to minimum 20 -ft at
outlet of 30" pipes
3. width at end of apron= 12 -ft +Do (pipe diameter); for double pipes add
center -to- center distance; for 30" pipe, width is 22.5 -ft
4. stone thickness =22 -in min. for Class B; for Class A: thickness =1 2 "; for
Rougemont no. 39: thickness =8"
5. underlay stone with filter fabric; all filter fabric shall have minimum permittivity
75 gal /min /sf
6. construct level surface for length and width inidcated, then provide smooth
transition to existing grade
La +Do
Roof, bio-garden drains:
1 width at pipe outlet =3 x pipe d --
2:' length ,beyond end of pipe =4 -ft min.
3' width at end =3 -ft min.
4 ,thickness =1 5 x max. aggregate size, (0.5 -ft min.)
5.' use Rougemont No. 39 stone or eq. underlain by filter fabric
FABRIC - use 8 -oz., non - woven, needle punched
3
f
lift j
station I /
� f1
UG eler. ---
c�
f
I
i
I
f
II
i
GR,
SITE INFORMATION
1. Address: 236 Blackwell Point Loop Road
2. Deed Book 441, Page 671
3. Size: 0.57 -acre, common area: 0.35 -ac.
4. Soil Type: Altavista (AaA) group C
5. Flood Zone: AE
STORMWATER INFORMATION
1. Deck area in Zone 2: 431 -sf
2. Minimum area of impervious surface drained to bio- retention: 431 -sf
3. Minimum required bio- retention surface area for
431 -sf impervious surface (12" ponding depth): 34 -sf (Simple Method)
4. Actual impervious drainage area to bio- retention (roof section): 655.5 -sf
5. Minimum constructed bio- retention surface area for
655.5 -sf impervious surface (12" ponding depth): 52 -sf (Simple Method)
6. Drawdown to 2 -ft below surface (3 -ft planting soil, K =1.5): -11.5 -hrs
crete driveway
GENERAL
1. Planter design /construction by others
2. direct designated roof outlet(s) to bio- retention basin; install stone
dissipators at all pipe outlets
3. grade exterior perimeter of planter to encourage surface runoff to
drain away from sides of planter
4. elevations shown on drawing may be modified by grader due to field
conditions; it is important to maintain elevation differentials between the
various parts of the stormwater structure, access to BMP, and
clearances to the buildings and other structures.
5. Retaining walls, if necessary, will be by others
crete driveway 6. EASEMENT to be arranged between owner, surveyor and governing
authority.
EROSION and SEDIMENT CONTROLS
1
asp Owner /developer must control erosion in accordance with North Carolina
General Statutes. Land disturbing activities shall be conducted in accordance
with requirements of NCDENR Land Quality Division and the local
Erosion Control Authority. Stabilize all disturbed surfaces within 15 -days of
disturbance
STORMWATER PIPING INSTALLATION
1. All piping and ancillary equipment shall be purchased, stored, unloaded and
moved, installed and tested in accordance with local regulations, the NC
Mechanical, Building and Plumbing Codes and Manufacturer's
specifications.
2. Installation and construction activities shall comply with OSHA requirements.
3. Manufacturer's instructions for installation, storage and maintenance of
R -o -w drainage pipe and other construction materials are assumed part of is
document.
35 -ft 4. All gravity drainage pipe shall be sloped minimum 0.5 %; slopes around
perimeter of structures shall drain away from residential foundation at
minimum 20:1 slope for first 10 -ft.
BIO- RETENTION GARDEN
(no- scale)
1310- GARDEN PLANTING INFORMATION
LATIN NAME
COMMON NAME
NO.
QUANTITY *
PLANTING
SPACING
\
l
1
0
- -
underground electric
SIZE
FT.
i
normaI water line 1
sub -drain
outlet 96'
note: possible re- location
of underground
electrical supply
�o t \1 - uv eic�- f... s
1 --- - -SS -_ 1
UNIT 2 proposed
\\ deck f
BIO- RETENTION BASIN
Bio- retention Basin Construction
1. OwnerAnstaller must verify that water table is at least 2 -ft below base of drainage layer.
2. Interior slopes around interior perimeter shall not exceed 3:1.
3. Unless indicated, no artificial conduits should intercept bottom or sidewalls of basin.
4. Prior to site grading, a sediment fence should be placed around the area that will be disturbed
5. Prior to excavation of the bioretention pit, a sediment fence should be placed around the basin area
6. Planting soil should consist of 85 % -88% sand (washed, medium), 8 % -12% fines (clay &silt), 3 % -5% organic matter; it
should have infiltration rate 1 "-2" per hour, and a P -index between 10 -30. Planting soils shall be of uniform composition
and contain no deleterious materials. Written approvaVicertification by a soil specialist will be required.
7. Planting soil shall be placed in lifts of 12 -18- inches without compaction. Installer should overfill to approximately 2 -in. above proposed
design elevation to allow for settlement. Planting soil surface should be level with no low areas.
8. Mulch layer shall consist of double or triple shredded hardwood mulch that is free of weed, seeds, soil, roots, or any substance not
consisting of bole or branch wood and bark. Mulch shall be shall be aged at least 12- months prior to placement and applied in a
uniform layer 2 -in to 4 -in depth. Mulch layer should be inspected after each rainfall event and repaired whenever necessary. A written
record of inspections, maintenance and repairs should be kept by owner.
9. Surface of planting soil should be level with no low areas.
10. Landscape and planting plan is shown on sheet C -2.
11. The underdrain discharge pipe shall be 4 -in diameter, sch 40 PVC, slotted or perforated installed as inidcated;
discharge outlet is 6 " -d; ends of cleanout pipe(s) shall be capped at grade for secondary use as liquid level monitors. Install cleanout
(4" min) at end of each pipe run and at all directional changes. Cleanouts should terminate greater than 12 -in above garden surface.
12. Underdrain layer shall be separated from planting soil and native soil using Filterweave 400 or approved equivalent. Filter fabric shall
have minimum permittivity 75 gal /min /sf
13. A stone dissipator should be installed at roof drain pipe outlet into planter and at underdrain outlet.
14. Sequece installation of sediment and erosion controls to minimize the contamination of the planting soil with silts and fines. Sediment
controls must be installed around the area to be disturbed before grading, and around the bioretention area before the excavation of
the trench or pit for the planting soil.
MISCLELLANEOUS NOTES:
1. The specific surface area indicated for the bio- retention garden describes the minimum level surface required.
3. Cleanouts shall be at least 4" diameter and terminate with caps greater than 12 -in above planting soil surface.
4. Elevations of bio- garden /detention components may be adjusted due to field conditions, however, it is important that relative elevations
and sizes remain consistant between different parts of the system. All changes must be pre- approved.
Bioretention Basin Construction & Planting Sequence
During construction, protect future bio- garden areas from sediment intrusion unless indicated otherwise. Bio - garden shall not be
constructed until after completion of activities that could impact future performance. All disturbed surfaces must be stabilized within
15 -days of disturbance. Biogarden uses 3 -ft planting soil and shall be mulched and planted.
Bioretention Area General Maintenance
1. Visually inspect soil monthly. Repair damage caused by erosion, etc.
2. Remove void areas in organic layer whenever necessary and add additional mulch where needed at least once per year in the spring.
3. Remove and replace all dead and /or diseased vegetation that is beyond treatment twice per year during the periods from 3/15 to 4/30
and from 10 /1 to 11/30.
4. Treat all diseased trees and shrubs whenever signs of disease or insect infestation are observed.
5. After completion of planting, water plant material; water regularly at the end of each day for 14 consecutive days.
6. Replace deficient stakes or wires whenever needed.
7. Remove support stakes and wires at the end of the first year.
8. Maintain written record of all inspections and maintenance.
9. For additional information, consult NCDENR BMP manual and maintenance agreement documents.
Stormwater System Maintenance
1. Monthly and after each rainfall event (especially in fall), check inlet /outlet paths to make sure they are free of debris, leaves and any
other deleterious materials that could restrict flow or infiltration of surface water.
2. Monthly and after each event, verify that inlet /outlet /overflow pipes are not blocked by debris and are free to flow.
1310- RETENTION PLANTER PROFILE
(no scale)
planter: 4'x13'x4.25' (hgt.)
6" overflow riser
12" above soil
2.5' clearance to bldg.
ex. grade 99.8'
12" ponding
planting soil 100'
w. 2 -3" hardwood
mulch layer
top of planter wall 101.25'
- clean -out ex. grade 99.1'
)ossible future
? -in overflow slot for future expansion
nvert at 9 -in above planting soil
at upper end filter fabric layers between
anti - seepage collar sand and stone, stone and native
12 -in #57 drainage layer soil; use Filterweave 400
with 4" slotted /perforated or approved equivalent
pipes - PVC sch 40 all filter fabric shall have minimum
permittivity 75 gal /min /sf
NOTE:
CONTRACTOR SHOULD INSTALL TO KEEP SURFACE ELEVATION OF PLANTING SOIL AT OR BELOW SURFACE ELEVATION OF EXTERIOR SOIL
ALLOW AT LEAST 2.5 -ft CLEARANCE TO FOOTING
end of FES
(flared end section)
(no FES on roof or
bio- garden drain outlet)
pi l
d is
Outlet Dissipator 1. width at pipe outlet =3 x pipe diameter (Do) (for double pipes, width is
(no scale) 3xDo plus center -to- center distance )
2. length beyond end of FES (La) =12 -ft minimum; increase to minimum 20 -ft at
outlet of 30" pipes
3. width at end of apron= 12 -ft +Do (pipe diameter); for double pipes add
center -to- center distance; for 30" pipe, width is 22.5 -ft
4. stone thickness =22 -in min. for Class B; for Class A: thickness =1 2 "; for
Rougemont no. 39: thickness =8"
5. underlay stone with filter fabric; all filter fabric shall have minimum permittivity
75 gal /min /sf
6. construct level surface for length and width inidcated, then provide smooth
transition to existing grade
La +Do
Roof, bio-garden drains:
1 width at pipe outlet =3 x pipe d --
2:' length ,beyond end of pipe =4 -ft min.
3' width at end =3 -ft min.
4 ,thickness =1 5 x max. aggregate size, (0.5 -ft min.)
5.' use Rougemont No. 39 stone or eq. underlain by filter fabric
FABRIC - use 8 -oz., non - woven, needle punched
3
f
lift j
station I /
� f1
UG eler. ---
c�
f
I
i
I
f
II
i
GR,
SITE INFORMATION
1. Address: 236 Blackwell Point Loop Road
2. Deed Book 441, Page 671
3. Size: 0.57 -acre, common area: 0.35 -ac.
4. Soil Type: Altavista (AaA) group C
5. Flood Zone: AE
STORMWATER INFORMATION
1. Deck area in Zone 2: 431 -sf
2. Minimum area of impervious surface drained to bio- retention: 431 -sf
3. Minimum required bio- retention surface area for
431 -sf impervious surface (12" ponding depth): 34 -sf (Simple Method)
4. Actual impervious drainage area to bio- retention (roof section): 655.5 -sf
5. Minimum constructed bio- retention surface area for
655.5 -sf impervious surface (12" ponding depth): 52 -sf (Simple Method)
6. Drawdown to 2 -ft below surface (3 -ft planting soil, K =1.5): -11.5 -hrs
crete driveway
GENERAL
1. Planter design /construction by others
2. direct designated roof outlet(s) to bio- retention basin; install stone
dissipators at all pipe outlets
3. grade exterior perimeter of planter to encourage surface runoff to
drain away from sides of planter
4. elevations shown on drawing may be modified by grader due to field
conditions; it is important to maintain elevation differentials between the
various parts of the stormwater structure, access to BMP, and
clearances to the buildings and other structures.
5. Retaining walls, if necessary, will be by others
crete driveway 6. EASEMENT to be arranged between owner, surveyor and governing
authority.
EROSION and SEDIMENT CONTROLS
1
asp Owner /developer must control erosion in accordance with North Carolina
General Statutes. Land disturbing activities shall be conducted in accordance
with requirements of NCDENR Land Quality Division and the local
Erosion Control Authority. Stabilize all disturbed surfaces within 15 -days of
disturbance
STORMWATER PIPING INSTALLATION
1. All piping and ancillary equipment shall be purchased, stored, unloaded and
moved, installed and tested in accordance with local regulations, the NC
Mechanical, Building and Plumbing Codes and Manufacturer's
specifications.
2. Installation and construction activities shall comply with OSHA requirements.
3. Manufacturer's instructions for installation, storage and maintenance of
R -o -w drainage pipe and other construction materials are assumed part of is
document.
35 -ft 4. All gravity drainage pipe shall be sloped minimum 0.5 %; slopes around
perimeter of structures shall drain away from residential foundation at
minimum 20:1 slope for first 10 -ft.
BIO- RETENTION GARDEN
(no- scale)
1310- GARDEN PLANTING INFORMATION
13'
The QUANTITY shown for each is the number of pthat type
of plant that will be planted in the garden locations indicated
on sketch below.
4' �� 00�
.0 00�0.�00
00 000�0000�0
$..8..8.
plant locations are approximate
adjust as necessary;
evenly distribute ground cover
Bio - garden area is 52 -sf with flat surface;
provide stone dissipators at all pipe outlets
Anti - seepage Collar
(typical - no scale)
extend min. 6 -in. into undisturbed earth
extend min. 12 -in. above and below pipe
trench wall -77
6" dia.
rain pig
concrete anti - seepage collar
concrete - 3,000 psi
planting soil area =52 -sf with 12" ponding depth
planting soil elevation = 100'
min. 52 -sf
- 4'x13' surface with
12" ponding depth
garden surface elev. 100'
underdrain outlet ~96'
overflow riser at elev 101''
top of planter wall 101.25'
10' 0 10' 20'
RN RN
Scale 1" = 10'
2 foot contour interval (GIS)
LEGEND:
0 IRON FOUND
IRON SET
O CALC. CORNER
❑ CONC. MONU.
stream buffer, riparian buffer
3,97 proposed contours
Ic planting, screening
deciduous tree
tree clearance
r
disturbed area
lsilt fence
check dam
bio - garden
LATIN NAME
COMMON NAME
NO.
QUANTITY *
PLANTING
SPACING
bicycle rack
_UG elec-
- -
underground electric
SIZE
FT.
Cn
M
_RCP (SW).=
=
1
-ss- -
- -
sanitary sewer
D
water
2
Cn
R -O -W
3
CAMA line
N
4
J
Q
Z
5
Z
6
w
a
7
Liriope muscaria
Liriope
8
-36
4" pots
8 " -12"
ASSES
9
13'
The QUANTITY shown for each is the number of pthat type
of plant that will be planted in the garden locations indicated
on sketch below.
4' �� 00�
.0 00�0.�00
00 000�0000�0
$..8..8.
plant locations are approximate
adjust as necessary;
evenly distribute ground cover
Bio - garden area is 52 -sf with flat surface;
provide stone dissipators at all pipe outlets
Anti - seepage Collar
(typical - no scale)
extend min. 6 -in. into undisturbed earth
extend min. 12 -in. above and below pipe
trench wall -77
6" dia.
rain pig
concrete anti - seepage collar
concrete - 3,000 psi
planting soil area =52 -sf with 12" ponding depth
planting soil elevation = 100'
min. 52 -sf
- 4'x13' surface with
12" ponding depth
garden surface elev. 100'
underdrain outlet ~96'
overflow riser at elev 101''
top of planter wall 101.25'
10' 0 10' 20'
RN RN
Scale 1" = 10'
2 foot contour interval (GIS)
LEGEND:
0 IRON FOUND
IRON SET
O CALC. CORNER
❑ CONC. MONU.
stream buffer, riparian buffer
3,97 proposed contours
Ic planting, screening
deciduous tree
tree clearance
r
disturbed area
lsilt fence
check dam
bio - garden
Topographic and boundary information are from Pamlico Cty GIS map and drawings
by Suitt & Associates, P.A. dated May & Nov 2008 and Feb 2011 provided by land
owner. Prior to beginning field activities, contractor should verify elevations and
locations of all existing boundaries, utilities, structures, and other appurtances both
aboveground and below. It will be contractor's responsibility to report deviations from
design drawings. Contractor will be responsible for repairs to damages as well as for
site restoration.
PRELIMINARY - NOT FOR CONSTRUCTION
...... ......... .....:....
DECK INSTALLATION
(variance request)
Developer /Owner /Applicant:
RIVERWINDS CONDOMINIUMS, LLC
Gwinn Hedrick
401 Vandemere Street
Oriental, NC 28571
Drawing Title
STORMWATER MANAGEMENT PLAN
ons:
Number Description Date
submittal 1 initial to DWQ for review 9 Aug 2012
rawn by: SAA
9 Aug 2012
1 of
1 " =10'
C -1
pp
power pole
FH
fire hydrant
bicycle rack
_UG elec-
- -
underground electric
_gas_ -
- -
gas pipe
_RCP (SW).=
=
stormwater
-ss- -
- -
sanitary sewer
water
R -O -W
CAMA line
Denotes Approx. Tree Line
Topographic and boundary information are from Pamlico Cty GIS map and drawings
by Suitt & Associates, P.A. dated May & Nov 2008 and Feb 2011 provided by land
owner. Prior to beginning field activities, contractor should verify elevations and
locations of all existing boundaries, utilities, structures, and other appurtances both
aboveground and below. It will be contractor's responsibility to report deviations from
design drawings. Contractor will be responsible for repairs to damages as well as for
site restoration.
PRELIMINARY - NOT FOR CONSTRUCTION
...... ......... .....:....
DECK INSTALLATION
(variance request)
Developer /Owner /Applicant:
RIVERWINDS CONDOMINIUMS, LLC
Gwinn Hedrick
401 Vandemere Street
Oriental, NC 28571
Drawing Title
STORMWATER MANAGEMENT PLAN
ons:
Number Description Date
submittal 1 initial to DWQ for review 9 Aug 2012
rawn by: SAA
9 Aug 2012
1 of
1 " =10'
C -1

Hedrick Bio- retention garden sizing
Simple Method for use where site has single or predominant type of surface or for quick estimates, urban sites
R(v) =0.05 +(0.009 *I)
increase
R(v)=
volumetric runoff coefficient
1=
site percent impervious
Hedrick SITE 1 I ( %) =
93
R(v)=
0.88
WQV= P *R(v)
0.00 ac.
WQV=
water quality volume in watershed inches
P=
rainfall in inches
Hedrick SITE 1 P (in)=
1
imp. ( %)
acres=
0.01
pavement
WQV=
0.88 watershed inches
1= site percent impervious
WQV (cubic feet)=
(watershed inches /12) *(acres *43560)
0.00 ac.
WOV=
34 cubic feet
707.5
12" depth garden 34 sf
9" depth garden 46 sf
UnecK minimum Dio- retention area for actual impervious surfaces aralnecl t0 garclen.
increase
bldg
431
0.01 ac.
pavement
0
0.00 ac.
drive & pking.
0
0.00 ac.
(incl. garden) drainage area
465
0.01 ac.
impervious area
431.00
0.01 ac.
imp. ( %)
0.02 ac.
93
12" depth garden 34 sf
9" depth garden 46 sf
UnecK minimum Dio- retention area for actual impervious surfaces aralnecl t0 garclen.
Simple Method for use where site has single or predominant type of surface or for quick estimates, urban sites
increase
R(v) =0.05 +(0.009 *I)
bldg
655.5
0.02 ac.
R(v)= volumetric runoff coefficient
pavement
0
0.00 ac.
1= site percent impervious
drive & pking.
0
0.00 ac.
Hedrick SITE 1 I ( %) = 93
(incl. garden) drainage area
707.5
0.02 ac.
R(v)= 0.88
WQV= P *R(v)
WQV= water quality volume in watershed inches
impervious area
655.50
0.02 ac.
P= rainfall in inches
imp. ( %)
93
Hedrick SITE 1 P (in)= 1
acres= 0.02
WQV= 0.88 watershed inches
WQV (cubic feet)= (watershed inches /12) *(acres *43560)
12" depth garden
52 sf
WQV= 52 cubic feet
9" depth garden
69 sf
SGI Tech
August 2012

BIOGARDEN draw down time
roof, pavement
area (ac) 0.018
composite C 0.96
CN 98
P (in) 1
determine runoff
S 0.00
runoff (in) 1.00
volume (ac -in) 0.00
volume (sf -in) 0
bio- garden depth (in) 9.0
SA (sf) 0
bio- garden depth (in) 12.0
SA (sf) 52
determine underdrain size and drawdown times
planting soil depth (ft) 3.0
soil permeability (in /hr) 1.5
determine draw through rate
Q (cfs) 0.002
K (in /hr) 1.5
A (sf) 52
dH 4.00
dL 3.00
time to draw from inundation
to saturation at surface
treatment area (sf) 52
depth (ft) 1.0
drawdown rate (cfs) 0.002
V (I -S) (cf) 52
T (I -S) (sec) 21739
T (I -S) (hrs) 6.0
time to draw from saturation
at surface to 2' below surface
soil porosity (n) 0.45
treatment area (sf) 52
ime to be removed from 2 -ft 47
drawdown rate (cfs) 0.002
T(S -2) 19565
T (S -2) 5.4
DRAWDOWN TIME (hrs) 11.5
PIPE SIZING N *D= 16 *(Q *n /(sA0.5))A.375
Q (cfs) 0.002
10 *Q (cfs) 0.02
n 0.013
s 0.005
N *D 0.88
Set gravel layer to provide 2" cover
Hedrick Bio- retention garden sizing
drawdown rate and underdrain sizing
SGI Tech
August 2012
Soil group C
DESIGN STORM
S= (1000 /CN -10)
P= ((P- 0.2 *S)A2) /(P +0.8 *S)
required surface area 9" ponding
surface area 12"
VEGETATION COVER - plants, shrubs
sandy loam (85 -88% sand;8 -12% silt +clay;3 -5% organics)
(2.3E- 5) *K *A *(dH /dL)
hydraulic conductivity of soil
surface area of bio- retention area
height of water above gravel envelope /drainage pipe zone
thickness of soil
volume
time
time
porosity percent
volume
sec
hrs
total
fos
Manning
0.5%
inches use 4" slotted pipe

OPERATION and MAINTENANCE of BMPs
DRAINAGEWAYS and STONE DISSIPATORS
1. Inspect and repair all surfaces after each rainfall event until vegetation is
established.
2. Remove deposited sediments to maintain original contours and grading.
3. Remove debris that collects.
4. Maintain sheet flow by repairing channels that develop at dissipators, within
approach areas and downstream from dissipators.
5. Re -seed and re- grade, as necessary, to maintain growth of vegetation.
BIO- RETENTION GARDEN
General Operations and Maintenance:
1. Immediately after the bio- retention cell is established, water plants twice
weekly until they become established. Twice weekly watering should
continue for at least six weeks.
2. Snow, mulch, or any other material should never be piled on the surface
of the cell.
3. Heavy equipment should never be driven over the bio- retention cell.
4. Special care must be taken to prevent sediments from entering the bio -
retention cell.
5. Periodic testing of the soil media is recommended. Evaluate results using the
initial acceptance test results as the base line.
6. After the bio- retention cell is established, it should be inspected once per
month and within 24 -hrs after every storm event greater than 1 -inch.
7. Written records of operation and maintenance should be kept in a known
location and should be available upon request.

Inspection Procedures:
1. Entire BMP - Remove all trash and debris.
2. Perimeter of the bio- retention cell — Regrade the soil as necessary to
remove any gullies that form. Replant ground cover where necessary and
water until established. Provide lime, only if indicated by soil test results.
3. Inlet devices, pipes, stone and swales - Maintain unimpeded flow by
repairing, regrading and /or replacing as necessary. Dispose of collected
sediments off -site.
4. Pretreatment areas — Regrade and re- establish ground cover when necessary
to prevent formation of gullies, to prevent accumulation of sediment, to
prevent erosion and to prevent surface flow from bypassing design flow paths.
Remove weeds as necessary. If persistent erosion is occurring, stabilize using
reinforced turf matting and /or rip -rap.
5. Bio- retention cell vegetation — Prune plants as necessary. At least twice
per year during the periods from 3/15 to 4/30 and from 10/1 to 11/30, replace
plants and /or ground cover that are diseased, dying, or dead. If soil tests
indicate it, fertilize to establish ground cover (one time only).
Remove stakes or wires when they are no longer necessary.
6. Bio- retention cell soils and mulch - Replace mulch in areas where voids
develop. If mulch is breaking down or has floated away, remove remaining
mulch and replace with 3 -inch layer of triple shredded hardwood mulch. If
mulch becomes sediment clogged, remove /replace the portion that is
clogged. Alternately, remove /replace entire 3 -in media layer.
The results of initial confirmation analyses on planting soil should be
used as a base line. If periodic soil tests demonstrate that pH is
dropping or heavy metals are accumulating, replace toxic soils and
plants /ground cover. If indicated by soil test, add dolomitic limestone.
When the filtering capacity diminishes substantially (indicated by water
ponding for more than 24 -hrs), the top few inches of material must be
removed and replaced with fresh material. Sediments removed must
be disposed of in an acceptable manner.
7. Bio- retention cell underdrain network — If clogging occurs, use cleanouts
to flush out system. Possible clogging will be indicated by increased
ponding duration and reduced discharge at outlet.
8. Bio- retention outlet pipe — Keep outlet clear of sediments and debris. If
erosion is occurring, regrade and repair as necessary. When indicated,
use cleanouts to flush pipes.
SPILLWAYS/WEIRS /RETENTION /DETENTION MAINTENANCE
For first six - months, inspect after each storm event, then quarterly. Verify that
C!!T

weirs and spillways remain level at pre -set elevation. Verify that outflow from
retention /detention is not passing under or around outside of pipes or weirs.
Repair, restore and /or re -build whenever devices are not functioning properly.
Quarterly and after a major rainfall event, inspect soil and stone surfaces
leading up to and away from outflow areas to verify that channeling or soil
erosion is not occurring. Repair /restore whenever erosion is evident. Stabilize
restored areas with seasonally appropriate grass or approved plants.
Quarterly and after a major rainfall event, inspect soil berms to verify that top
elevation remains at or above the design elevation and at least 0.25' above the
topmost elevation of the overspill device (weir). Repair /restore and stabilize
berms as necessary using soil and seasonally appropriate grass or plants.
SPECIAL REMINDER TO OWNER: Keep a written record of inspections,
repairs, and miscellaneous activities associated with all stormwater
devices.
OWNER'S SIGNATURE(S) CONFIRMING RESPONSIBILITY FOR BMP MAINTENANCE
DATE
C!!T

L_
Certificate of Survey and Accurac
I, Chet M. Suitt, certify that this plat was drawn under my supervision from
an actual survey made under my supervision (deed description recorded in
Book 441, Page 671); that the boundaries not surveyed are indicated as
drawn from information found in Book 399, Page 227; that the ratio of
precision is 1:10,000; that this survey creates a subdivision of land within the
area of Pamlico County that has an ordinance that regulates parcels of land;
that this plat was prepared in accordance with G. S. 47 -30 as amended and
this map meets the requirement of The Standards of Practice for Land
Surveying in North Carolina (21 NCAC 56.1600). This 24th day of February,
A.D., 2012.
0,,1s»111,," 1
01k\11,0
1�
Owner
Riverwinds Condominiums, LLC
Gwinn Hedrick
401 Vandemere Street
Oriental, NC 28571
Address:
236 Blackwell Point Loop Road
Deed Reference:
Riverwinds Condominiums, LLC
Deed Book 441, Page 671
Tax Map Number J082 -36
Map References:
Property Survey For Gerald D. Hedrick
and wife Anne P. Hedrick
Deed Book 399, Page 227.
Boundary Survey For Robert Parker
& wife, Linda Parker
Deed Book 460, Page 390.
Survey For Oriental Professional Properties, LLC
Deed Book 449, Page 934.
Pamlico County Registry.
Subdivision to be served by central water supply and
central sewage treatment system.
Acreage of Total Tract is 0.57.
Acreage of Common Areas is 0.35.
Total Number of Parcels Created is 7.
Flood Report:
This property is located in Zone AE per Flood
Insurance Rate Map Number 3720648600,
Community Number 370181, Panel Number 6486,
Suffix J. Effective Date: July 2, 2004.
Area by coordinate computations.
Underground utility locations were marked by paint
by others.
Notice to Prospective Purchasers (Environmental Matters)
The Army Corps of Engineer, Coastal Area Management Act and Division of
Water Quality area of regulatory jurisdiction depicted on this map, if any,
are for information purposes only. The exact location of these areas of
regulatory jurisdiction are subject to future precise delineation by various
state and federal agencies and may change over time due to changes in the
physical characteristic of the land depicted on this plat, or due to future
statutory and regulatory amendments. Prior to purchasing any property
shown on this plat, individuals are advised to independently verify that any
particular lot is suitable for the planned or intended use, as subdivision
approval by Pamlico County does not constitute any warranty (express or
implied) and the land depicted on this plat is suitable for any particular use.
Service By Governmental Entity
Lots depicted on this plat are permitted for sewer service by Bay River
M51), permit /authorization number WQ0028683. Prior to purchasing any lot
depicted on this plat, Purchasers are advised to verify the continuing validity
of the aforesaid permit or authorization, as well as the costs to connect to
such system as the continuing and indefinite availability of sewer service is
not guaranteed by Pamlico County.
REVIEW OFFICER
STATE OF NORTH CAROLINA
COUNTY OF PAMLICO
I, , Review Officer of Pamlico County,
certify that the map or plat to which this certification is affixed meets all
statutory requirements for recording.
Review Officer
Date
4119,2
REGISTER OF DEEDS
STATE OF NORTH CAROLINA
PAMLICO OF CRAVEN
Filed for Registration at AM /PM o'clock This
day of It 2011. Plat Cabinet Slide
L%6414 K. 1-"15
Certification of No Approval Required
Pamlico County Subdivision Administrator Date
Point B
7.55' :fZ--�, 1
Approximate Normal L9 v
Register of Deeds /Assistant /Deputy Water Line (5/13/2008)
Existing Metal Stake Found
North East Corner of Property
Described Per Deed Book 460, Page 388 EPK Found At The Intersection
r' of Blackwell Point Loop Road
r�
+fl �
Robert Jerome Parker, Jr.
& Linda White Parker + •a
Deed Book 460, Page 388. i o
r Tie Line J
;-, Reference Bearing
C E S86 °04'45" 190 Transformer
.16' (EMS - EMS) Electric r I
182.61' i 41
Sewer Lift Cable TV i ,
Station Pedestal r �_J
MBL Retaining wall
-'g -- Sewer Lift Station Control Panel
Mooring-Pole Pergola SS"2 E 63.5 -- - r-
`; (Typical) \ Walkway 0 g 51, 4 (4) water
g W 52.3
�� Need Not Be ;° w LOT 1 _ � Meters j C\1 r'N
►` Built �0 c�i C] 1.,41.0 SQ. FT. - �. � 0 r
0.03 ACRES -ni ;° ® �v, i o
L25 .� N ° ® Nir•
\ 585 °12'36 "E Lot 1's w Is
2,
� 53.72' L12 , w w - C
I P N w 1,4 1 SQ. FT. -�- N LIMITED o I
Q 0.03 ACRES in COMMON 1 LO
% �0' Z L24 AREA -�
% _ 585 °07'53'�E o ix
Wood C LU 53.62, L13 Lot 2's ells a
4 Dock Boundary Line Plotted From Information - ,� �`_
Recorded in Deed Book 399 Page 227. ° v LOT 3 0 � 9
I;L:n. °� N o 1,404 SQ. FT. f °1 r
0 0.03 ACRES 7 �; � � � -
�, 5 Fish Cleaning 58500 08 "E I,- ca -tea
Iy Table \ ti 53.51' L14 L o m
LOT 4 u_ o
Smith Creek ' 6 0
� r 7
LINE TABLE Point A to
Point B)
LINE
BEARING
DISTANCE
Ll
N12 054'35 "E
2.09'
L2
N15 °33'05 "W
11.78'
L3
NO2 029' 15" W
1.61'
L4
N18 046'00 "W
30.46'
L5
N24 °43' 39 "W
66.27'
L6
N26004' 15 "W
4.95'
L7
N26 °46'00 "W
52.09'
L8
N31047' 14 "W
47.74'
L9
N79 °07' 31 "E
4.11'
L10
N15034'21 "E
3.95'
L11
N38043' 29 "W
0.34'
Final Plan of
RIVERWINDS T❑WNH❑MEIS
Near Oriental, Number Two Township, Pamlico County, North Carolina
Deed Reference:
Riverwinds Condominiums, LLC
Deed Book 441, Page 671
Pamlico County Register of Deeds
AM, Plotted By, Chet Suitt, PLS
t $
10
b-'
LINE TABLE
LINE
BEARING
DISTANCE
L12
585012'36"E
10.00'
L13
585007'53"E
9.81'
L14
584049'53"E
9.96'
L15
504 043'48 "W
0.49'
L16
585 018'34 "E
10.00'
L17
584 052'03 "E
10.01'
L18
585005'36"E
7.02'
L19
N84051'43 51W
8.95'
L20
N85 005'59 "W
9.02`
L21
N84 °56' 33 "W
9.93 `
L22
N85 006'08 "W
9.97'
L23
N85 °04'08 11W
9.95'
L24
N85 °07'53 "W
10.19'
L25
N85 °12' 36 "W
10.00'
L26
585 006'08 "E
20.64'
L27
N05 015'26 "E
0.18'
p
p,✓K
Wood
Dock
< E'? o► x $'�' a
1,384 SQ. FT. \ N V LIMITED vJ
3 o`r 0.03 ACRES ..; m COMMON I
`� °� AREA
Z I
` 02 L22 L26 cu. 585 °11 l2„ j 1
q UJ 32.85'
x rn L16
Wood ►� N V LOT 5
Bulkhead ` cc 4 1,420 SQ. FT. \ ! ) --
0.03 ACRES fm N Paved et
° " c aved Road
L21 584 °56'33 "E L17
3oa w 53.53'
m
TOTAL PROPERTY �\ cy m v LOT 6
BOUNDARY AREA °� N W 1,4115Q. FT. �. �-
0 �~ v
24,907 SQ. FT. 0.03 ACRES �� i ix
0.57 ACRES
L20 o
50 5 „ -4 h
3
1 w S85° ,9E 0- L18 L18 3 .°4-
54.49
1 0 1 i
2
°D ac- V ib y e�j N CL
o�
N 9 0 ..; �l C ° t
0
L19 LOT 7
f 1 u�
ua 2,143 SQ, FT Ito
is 0.05 ACRES
Approximate Normal { cc Y c>a
Water Line (5/13/2008) 1 ? in v ! 3
o. _1
Z N85 °10'06 "W 44..00'
Point -8' MBL - --
L
8.14' r-- w
N86 056155 'W 85.12' (M) (SPK - EMS) i Elect icrmer
N86 °37'55 "W 86.96' R r
End wood () r_w EPK In The Base of The
Fence �!;; ElectricTransfarmer
Oriental Professional Properties, LLC (2) Electric °ro%
Deed Book 449, Page 931. Meter Boxes I I
CU F so
�Jz
r'
Existing Metal Stake Found
South East Corner of Property
Described Per Deed Book 449, Page 931
LINE LEGEND
PROPERTY LINE
PROPERTY TIE LINE
- W --- -
PROPERTY LINE NOT SURVEYED
MINIMUM BUILDING SETBACK LINE
CAMA LINE
RIGHT OF WAY
R/W - - R/W
EDGE OF PAVEMENT
EP EP
ABBREVIATIONS
UNDERGROUND ELECTRIC
R/W = RIGHT OF WAY
(PAINTED LOCATION MARKED BY OTHERS)
SQ.FT. = SQUARE FEET
-UGE
CAMA = COASTAL AREA MANAGEMENT AGENCY
UNDERGROUND SANITARY SEWER
L1 = LINE NUMBER
(PAINTED LOCATION BY OTHERS)
(R) = RECORD
55
(M) = MEASURED
UNDERGROUND WATER LINE
MBL = MINIMUM BUILDING SETBACK LINE
(PAINTED LOCATION BY OTHERS)
EMS = FOUND EXISTING METAL STAKE
W
EPK = FOUND EXISTING PARKER KALON NAIL
WV
Project # 4119 Revisions:
Field Book: 223133 -37 02/24/2012 - Per Owner/Attorney Comments.
Drawn By: CS
Approved By: CS
Dates:
Field Survey - 5113,14 & 1912008, 10/31/2011 & 1111 & 212011
Mapping - 05115,16,19 & 20/2008,10/14&1.712011, 1111&212011 & 02/24/2012
SYMBOL LEGEND '
*
FOUND EXISTING METAL STAKE
O
FOUND EXISTING PARKER KALON NAIL.
O
SET NEW METAL STAKE
1=T
ELECTRIC TRANSFORMER
19
CABLE TV PEDESTAL
©
WATER METER
0
SEWER MANHOLE
SEWER CLEANOUT
®
WELL
WV
WATER VALVE
ELECTRIC METER BOX
GRAPHIC SCALE
20' 01 10' 20- 4a-
( W US SURVEY FEET )
1 inch = 20 ft-
6
-CINDY M
a
J"
N
N
z�
UJ
rx o
zz °o
/ X 'ORIENI'AL
�
Greens �
Creek
NORTH
SUITT & A55 [30IATES, P.A.
FIRM LICENSE N©. 0-1 155
CHET M. SulT -r, PLS L-2995
LAND SURVEYORS SINCE 1965
P.O. Box 12034
NEW BERN, NO 213561 -20 .34
TEL. [phone] / FAX: [phone]
WWW.SUlrrSURVEY.l3QM