20061804 Ver 7_Site Work Calculations_20130819

OLD -
80AVI
Soil & Environmental Consultants, PA
11010 Raven Ridge Road • Raleigh, North Carolina 27614 • Phone: [phone] • Fax: [phone]
www.SandEC.com
August 16, 2013
S &EC Project # 6658.P6
To: N.C. Division of Water Resources
Water Quality Programs- WeBSCaPe Unit
Attn: Karen Higgins
512 N. Salisbury Street -9`h floor
Raleigh, NC 27603
Re: The Village at Flowers Plantation
Stormwater Management Plan -POD NW-8 (Phase II)
DWQ Project #20061804, Ver.3 /Certification No. 3766
Johnston County, NC
On behalf of Mrs. Rebecca Flowers, please find the attached Stormwater Management Plan for
POD NW-8 (Phase II). According to the Individual 401 Water Quality Certification Approval
Certification No. 3766, Condition No. 9, "a final, written stormwater management plan for each
phase of this project shall be submitted to the DWQ 401 Oversight/Express Permitting Unit for
review and approval". Therefore, please see attached Stormwater Management Plan for your
review and anticipated Approval. Please contact me at DShirlev(aD_SandEC.com or (919) 846-
5900 if you have any questions.
Sincerely, D
Soil & Environmental Consultan s, PA
4,,J, e2- AUG 1 9 2013
Deborah Edwards Shirley
Environmental Specialist
Attachments:
1) Flowers Plantation Pod NW -8 (Phase IIA) Sitework Calculations
2) Bioretention Operations & Maintenance Agreement- signed and notarized
3) Overall POD map (east side of Buffalo Rd.)
4) POD -NW -8 (Phase II) Runoff Maps -C -1 & C -6
5) POD NW-8 (Phase II) Overall Site Plan -C -1
6) POD NW-8 (Phase II) Street Plan & Profiles -C -2 & C -3
7) POD NW -8 (Phase II) Bioretention Details -C-4
8) POD NW -8 (Phase II) Master Grading Plan -C -5
9) POD NW-8 (Phase II) Erosion & Sediment Control Plan -C-6
10) POD NW -8 (Phase II) Erosion & Sediment Details -D -01
11) POD NW -8 (Phase II) Utilities Details -D -02 & D -03

Flowers Plantation
Pod NW 8
Phase IIA
Owner /Developer:
Rebecca Flowers
4880 NC 42 East
Clayton, NC 27520
aE�
AUG 1 9 2013
Phone: [phone]
Am
0,,%IM$ still �I
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STOCKS ENGINEERINQ P.A.
1100 Eastern avenue Phone: [phone]
PO Box 1108 Fax: [phone]
Nashville, NC 27856 Mobile: [phone]
Email: [e-mail]

Stocks Engineering, PA.
1100 Eastern Avenue
PO Box 1108
Nashville. NC 27856
Project: Flowers-Pod NW 8 Phase 2A
Date: August 1, 2013
page: I of I
Post - Development
TO
W 6f.4)
5
la
0.77
0.75
7.40
4.27
5
Ila
0.95
0.42
7.40
2.95
5
Ilb
0.09
0.95
7.40
0.63
5
11C
0.22
0.95
7.40
1.55
5
lid
4.34
0.39
7.40
12.53
1
1
1
1
Total
1 6.37
1 -
7.40
I
Post - Development
Runoff Computations
10-Year Storm
25-Year Storm
W 6f.4)
5
la
0.77
0.75
8.40
4.85
5
Ila
0.95
0.42
8.40
3.35
5
Ilb
0.09
0.95
8.40
0.72
5
11C
0.22
0.95
8.40
1.76
5
lid
4.34
0.39
8.40
14.22
1
1
1
1
Total
1 6.37
1 -
SAO
I
Runoff Computations
10-Year Storm
25-Year Storm

Permit Number
(to bep byDINO)
OF WA7�
A $ V�
9� O Y
HC OM
STORMWATER MANAGEMENT PERMIT APPLICATION FORM
401 CERTIFICATION APPLICATION FORM
BIORETENTION CELL SUPPLEMENT
This form must be fulled out, printed and submrted.
The Required Items Check&t (Part III) must be printed, tilled out and submitted along with ak of ft required kdonnation.
�A. " -';YU _ `"!„-%,l'.,� "xL�- !� »ir' •.".: � ��cc- � - Y,' -.�� - _ ,_ -tit 4� - •, Y, �- _- ...,_,., _ _ _
1= E �iRMATtON� - - _- _ r�;: -�..�: �= �-- :F.��..y�;� :a.,� ;, >- _��'•_ :� :.;7;. "� - _ „ °.,,>;• __ ";c - :. : =: ,
Project name Fbwers Plantation - Pod NW 8 (Phase 2)
Contact name Kevin Vamell
Phone number 252.459.8196
Date July 22, 2013
Drainage area number 1
!l :�Q�SIGN�Nt~O1�MATl0�1 ” -- �'� : - _ - - - - = w -t'Y• - •h h - -; - - - _ _ ,t >: -- - - _ •:_ ;;
Site Characteristics
Drainage area 361,981 ft=
Impervious area 130,500 ft2
Percent impervious 36.1% %
Design rainfall depth 1.0 inch
Peak Flow Calculations
Is pro/post control of the 1 -yr, 24-hr peak flow required?
Y (Y or N)
1 -yr, 24-hr runoff depth
3 In
1 -yr, 24-hr intensity
0.12 Irllhr
Pre-development 1 -yr, 24-hr peak flow
0.668 ft%w
Post - development 1 -yr, 24-hr peak flow
0.491 fekm
Pm/Post 1 -yr, 24 -hr peak control
-0.177 ft %sc
Storage Volume: Non-SA Waters
Minimum volume required
11,297.0 ft'
Volume provided
12,146.0 fit
OK
Storage Volume: SA Waters
1.5" nm ff volume
ft2
Pre - development 1 -yr. 24-hr runoff
ft�
Post - development 1 -yr, 24-hr runoff
ft2
Minimum volume required
0 ft
Volume provided
fe
Cell Dimensions
Ponding depth of water
12 inches
OK
Ponding depth of water
1.00 ft
Surface area of the lop of the biorelention cell
14,485.0 ft2
OK
Length:
ft
Width:
It
-or- Radius
ft
Media and Soils Summary
Drawdown time, ponded volume
6 hr
OK
Drawdown time, to 24 inches beim surface
18 hr
OK
Drawdown time, total:
24 hr
In -situ soil.•
Soil permeability
010 In/hr
Insufficient. Increase infiltration rate or include underdrains.
Planting media soil:
Soil permeability
2.00 IrAr
OK
Soil composition
% Send (by volume)
86%
OK
% Fines (by volume)
10%
OK
% Organic (by volume)
4%
OK
Total:
100%
Phosphorus Index (P- Index) of media
30 (unitless)
OK
Form SW401- 131oreter►tion•Rev.e
June 25, 2010
Pans 1 and II. Design Summary, Page 1 of 2

Permit Number-_.
(to be pruvrded by DWQ)
Basin 13evations
Temporary pod elevation
Y
248.00 fmsl
OK
Type of bioetention cep (answer'Y' to only one of the two
following questions):
Y
(Y or N)
OK
Is this a grassed cell?
Y
(Y or N)
OK
Is this a cell with treestshrubs?
N
(Y or N)
OK
Ranting elevation (top of the mulch or grass sod layer)
247 fmsl
Depth of mulch
him
OK
Bottom of the planting media soil
N
245 frost
OK
Planting media depth
2 ft
Depth of washed sand below panting media soil
N
0.33 ft
OK
Are underdrains being installed?
Y
(Y or N)
OK
How many dean out pipes are being installed?
20
OK
What factor of safety is used for sizing the underdrains? (See
BMP Manual Section 12.3.6)
2
OK
Additional distance between the bottom of the planting media and
1 R
the bottom of the cell to aocourd for underdrains
OK
Bottom of the cell required
243.67 fmsl
SHK elevation
240 fmsl
Distance from bottom to SHWT
3.67 It
OK
IMemal Wrier Storage Zone (MI5)
Does the design include IWS
N
(Y or N)
Elevation of the top of the upturned elbow
fmsl
Separation of IWS and Surface
247 it
Planting Plan
Number of tree species
0
Number of shrub species
Number of herbaceous groundcover species
Addigonal Information
Does volume in excess of the design volume bypass the
Y
(Y or N)
OK
bioretention cell?
Does volume in excess of the design volume flow evenly distributed
N
(Y or N)
Excess volume must pass through filler.
through a vegetated filer?
What is the length of the vegetated fitter?
it
Does the design use a level spreader to evenly distribute flow?
N
(Y or N)
Show how flow is evenly distributed.
Is the BMP located at least 30 feet from surface waters (50 feet if
Y
(Y or N)
OK
SA waters)?
Is the BMP localed at least 100 feet from water supply wells?
Y
(Y or N)
OK
Are the vegetated side slopes equal to or less than 3.1?
Y
(Y or N)
OK
Is the BMP located in a proposed drainage easement with access
Y
(Y or N)
OK
to a public Right of Way (ROW)?
Inlet velocity (from treatment system)
0.22 fVsec
OK
Is the area surrounding the cell likely to undergo development in
N
(Y or N)
OK
the future?
Are the slopes draining to the bloretention cep greater than 20%?
N
(Y or N)
OK
Is the drainage area permanently stabilized?
Y
(Y or N)
OK
Pretreatment Used
(Indicate Type Used with an ')C in the shaded cell)
Gravel and grass
(flinches gravel followed by 3.5 it of grass)
Grassed swale
OK
Forebay
X
Other
Form SW401431oretantion -Rev.8
June 25. 2010 Parts 1 and II. Design Summary, Page 2 of 2

Permit No:
& be a&*wdbyOWQ)
i11.:�RUIRED �i�BIS:�MEC�I�ST�.- - - - - _,° - _ ,5= •t.= _ ,,,` Y _ _ _ � - _ =� =� -
Please indicate the page or plan sheet numbers where the supporting documentation can be found. An incomplete submittal package will
result in a request for additional fnfonrivitlaiL This will delay final review and approval of the project. Initial in the space provided to
indicate the following design requirements have been met. If the applicant has designated an agent, the agent may initial below. If a
requirement has not been met, attach justification.
Paget Plan
Initials Street No.
C- -1
1. Plans (1' - 50' or larger) of the entire site showing:
Design at ultimate build -oul,
Off-site drainage (if applicable),
- Delineated drainage basins (include Rational C coefficient per basin),
- Celt dimensions,
- Pretreatment system,
- Hgh flow bypass system,
- Maintenance access,
- Recorded drainage easement and pubic right of way (ROW),
- Clean out pipe locations,
- Overflow device, and
- Boundaries of drainage easement.
2. Plan details (1" = 30' or larger) for the bioretention cep showing:
- Cell dimensions
- Pretreatment system,
- Hgh flow bypass system,
- Maintenance access,
- Recorded drainage easement and public right of way (ROW),
- Design at ultimate buffd -out,
- Off -efte drainage (if applicable),
- Clean out pipe locations,
- Overflow device, and
- Boundaries of drainage easement.
- Indicate the P -Index between 10 and 30
3. Section view of the bioretention cell (1" = 20' or larger) showing:
Side slopes, 3:1 or lower
- Underdrain system (if appOcabie), and
- Bioretenlion cell layers [ground level and slope, pre - treatment, pondfng depth, mulch depth, fill media
depth, washed sand, filler fabric (or choldng stone if applicable), #67 stone, underdrains (if applicable),
SHWT level(s), and overflow structure]
4. A sods report that is based upon an actual fold investigation, soil borings, and infiltration tests. The
results of the soils report must be verified in the field by DWO, by completing & submitting the soils
investigation request form. County soil maps are not an acceptable source of soils information. All
elevations shall be in feet mean sea level (fmsl). Results of soils tests of both the planting sal and the in
situ soil must include:
Soil permeability,
- Soil composition (% sand, % fines, % organic), and
- P- index.
5. A detailed planting plan (1' = 20' or larger) prepared by a qualified individual showing:
- A variety of suitable species,
Saes, spacing and locations of plantings,
- Total quantity of each type of plant specified,
A pianlmg detail,
The source nursery for the plants, and
- Fertilizer and watering requirements to establish vegetation.
C
6. A construction sequence that shows how the bioretention oell will be protected from sediment until the
entire drainage area is statifted,
C4LCS
7. The supporting calculations (including underdrafn calculations, if applicable).
D A
8. A oopy of the signed and notarized inspection and maintenance (I &M) agreement
14A
9. A copy of the deed restriction.
Form SW401- BkweWntbn -Rev.7
Part III, Page 1 of 1

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Hydraflow Plan View
c6 9
1 -- . outfaii
I Project File: Pod NW8 Phase 2 Pipes 8 -9.stm I No. Lines: 1 08 -01 -2013 J
"As && sbrm SWAWS zoos

Storm Sewer Summary Report
Page 1
Line
No.
Line ID
Flow
rate
0%)
Line
size
(in)
Line
length
(ft)
Invert
EL Dn
(ft)
Invert
EL Up
(ft)
Line
slope
N
HOL
down
(ft)
HOL
up
(it)
Minor
loss
(ft)
HOL
Junct
(ft)
Dns
line
No.
1
FES 8 to CB 9
4.27
15 c
54.0
290.00
292.70
5.000
290.83
293.53
Na
294.111
End
Project File: Pod NW8 Phase 2 Pipes 8-9 stm
Number of lines: 1
Run Date- 08-01 -2013
NOTES: c = cir, e = ellip; b = box; Known Qs only ; i - Inlet control.
Hydmlow Slam SwMe 2005

Hydraulic Grade Line Computations
Page 1
Une
Sipe
(in)
Q
(cfs)
Downstream
Len
(ft)
Upstream
Check
JL
coeff
Minor
loss
(ft)
Invert
elev
(ft)
HGL
elev
(ft)
Depth
(ft)
Area
(sgh)
Vol
(file)
Vol
head
(ft)
EGL
elev
(ft)
Sf
N
Invert
elev
(ft)
HGL
elev
(ft)
Depth
(ft)
Area
(sgft)
Vel
(ft's)
Vol
head
(ft)
EGL
elev
(ft)
Sf
Ave
Sf
Enrgy
loss
(ft)
(K)
1
15
4.27
290.00
290.83
0.83
0.86
4.96
0.38
291.21
n/a
54.0
292.70
293.53
0.83"
0.86
4.96
0.38
293.911
n/a
n/a
n/a
1.00
n/a
Project File; Pod NW8 Phase 2 Pipes 8 -9.stm
Number of lines: 1
Run Date: 08-01 -2013
Notes: ; "" Critical depth.
Hydreflow Sh ml Saws 2005

��■�� i���mmlmmm?w-- _low r

Storm Sewer Profile Proj. file: Pod NW8 Phase 2 Pipes 3 -7.stm
Hydrefiow Storm Sewers 2005
_y
id
1 1
• 1 /
-
- -11 III I
- -�
- - --
' / 1
1 1
11 1
11
1 11 1 11 I
11
Hydrefiow Storm Sewers 2005

VLbwgi s Ww 8 !?Kmr -'¢
Cvtzj pc N vv�f>&e-
►i.
(`�•3t Ac k ss� '/• 8.31 4e
f KpSe u t c0u S
3. oc • C- k 9 8� -� � 6. 31 Pte. 31 o4c
Ul = 7q

Watershed Model Schematic
1 - Pre Development
Project: Pre vs Postgpw
Hydrallow Hydrographs by IntelWve v9.22
2 - Post Development
3 - Outflow vp
Monday, Aug 5, 20'13

Hydrograph Return Period Recap HydraflowHydrographsbylMelisolvev9 .22
Hyd.
Hydrograph
Inflow
Peak Outflow (cfs)
Hydrograph
No.
type
Hyd(s)
description
(origin)
1 -Yr
2 Yr
3-Yr
5-Yr
10 Yr
25-Yr
50-Yr
100-Yr
1
SCS Runoff
0.668
--
--
-----
—_
—
Pre Development
2
SCS Runoff
---- --
11.76
—
—
—
—
—
—
Post Development
3
Reservoir
2
0.491
----
—
--
--
—
---
—
Outflow
Proj. file: Pre vs Postgpw
Monday, Aug 5, 2013

Hydrograph Summary Report
Hydrafiow Hydrographs by Intelisohre v9.22
Hyd.
No.
Hydrograph
type
(origin)
Peak
flow
(cts)
Time
interval
(min)
Time to
peak
(min)
Hyd.
volume
(cult)
Inflow
hyd(s)
Maximum
elevation
('10
Total
strge used
(cuff)
Hydrograph
description
1
SCS Runoff
0.668
2
720
4,710
—
—
- --
Pre Development
2
SCS Runoff
11.76
2
718
23,733
—
—
--
Post Development
3
Reservoir
0.491
2
834
10,435
2
248.04
13,899
Outflow
Pre vs Post.gpw
Return Period: 1 Year
Monday, Aug 5, 2013

Pre Development
Q (Cft) Hyd. No. 1 —1 Year
1.00
0.90
0.80
0.70
0.60
0.50
0.40
0.30
0.20
0.10
000
Q WS)
1.00
0.90
0.80
0.70
0.60
0.50
0.40
0.30
0.20
0.10
000
0 120 240 360 480 600 720 840 960 1080 1200 1320 1440 1560
® Hyd No. 1 Time (min)
4
Hydrograph
Report
Hydraflow Hydrographs by Intelisohre v9.22
Monday, Aug 5, 2013
Hyd. No. 1
Pre Development
Hydrograph type
= SCS Runoff
Peak discharge =
0.668 cfs
Storm frequency
= 1 yrs
Time to peak =
720 min
Time interval
= 2 min
Hyd. volume =
4,710 cuft
Drainage area
= 8.310 ac
Curve number =
55
Basin Slope
= 8.0%
Hydraulic length =
1200 ft
Tc method
= KIRPICH
Time of conc. (Tc) =
4.85 min
Total precip.
= 2.89 in
Distribution =
Type II
Storm duration
= 24 hrs
Shape factor =
484
Pre Development
Q (Cft) Hyd. No. 1 —1 Year
1.00
0.90
0.80
0.70
0.60
0.50
0.40
0.30
0.20
0.10
000
Q WS)
1.00
0.90
0.80
0.70
0.60
0.50
0.40
0.30
0.20
0.10
000
0 120 240 360 480 600 720 840 960 1080 1200 1320 1440 1560
® Hyd No. 1 Time (min)

Q (cis)
12.00
10.00
8.00
6.00
4.00
200
Post Development
Hyd. No. 2 —1 Year
Q (cfs)
12.00
10.00
8.00
6.00
It, Kill]
2.00
0.00 ' ' r 0.00
0 120 240 360 480 600 720 840 960 1080 1200 1320 1440 1560
Time (min)
® Hyd No. 2
5
Hydrograph
Report
Hydraflow Hydrographs by Intelisohm v9.22
Monday, Aug 5, 2013
Hyd. No. 2
Post Development
Hydrograph type
= SCS Runoff
Peak discharge =
11.76 cfs
Storm frequency
= 1 yrs
Time to peak =
718 min
Time interval
= 2 min
Hyd. volume =
23,733 cuft
Drainage area
= 8.310 ac
Curve number =
74
Basin Slope
= 8.0%
Hydraulic length =
1200 ft
Tc method
= KIRPICH
Time of conc. (Tc) =
4.85 min
Total precip.
= 2.89 in
Distribution =
Type II
Storm duration
= 24 hrs
Shape factor =
484
Q (cis)
12.00
10.00
8.00
6.00
4.00
200
Post Development
Hyd. No. 2 —1 Year
Q (cfs)
12.00
10.00
8.00
6.00
It, Kill]
2.00
0.00 ' ' r 0.00
0 120 240 360 480 600 720 840 960 1080 1200 1320 1440 1560
Time (min)
® Hyd No. 2

Storage Indication method used.
Q (Cfs]
12.00
10.00
8.00
6.00
4.00
2.00
0 (cfs)
12.00
10.00
8.00
O 1,
4.00
KI.X
0.00 ' I F I ' 0.00
0 120 240 360 480 600 720 840 960 1080 1200 1320 1440 1560
Time (min)
--- Hyd No. 3 - Hyd No. 2 RTUTTU Total storage used = 13,899 tuft
6
Hydrograph
Report
Hydraflow Hydrographs by Intelisolve v9.22
Monday, Aug 5, 2013
Hyd. No. 3
Outflow
Hydrograph type
= Reservoir
Peak discharge
= 0.491 cfs
Storm frequency
= 1 yrs
Time to peak
= 834 min
Time interval
= 2 min
Hyd. volume
= 10,435 cuft
Inflow hyd. No.
= 2 - Post Development
Max. Elevation
= 248.04 ft
Reservoir name
= <New Pond>
Max. Storage
= 13,899 cuft
Storage Indication method used.
Q (Cfs]
12.00
10.00
8.00
6.00
4.00
2.00
0 (cfs)
12.00
10.00
8.00
O 1,
4.00
KI.X
0.00 ' I F I ' 0.00
0 120 240 360 480 600 720 840 960 1080 1200 1320 1440 1560
Time (min)
--- Hyd No. 3 - Hyd No. 2 RTUTTU Total storage used = 13,899 tuft

Pond Report '
Hydraflow Hydrographs by Intelisolve v9.22 Monday, Aug 5, 2013
Pond No. 1 - <New Pond>
Pond Data
Contours - User - defined contour areas. Conic method used for volume calculation. Begining Elevation = 247.00 It
Stage / Storage Table
Stage (ft) Elevation (ft) Contour area (sgft) Incr. Storage (cuft) Total storage (cuft)
0.00
247.00
12,146
0
0
1.00
248.00
14,485
13,297
13,297
1.75
248.75
16,880
11,749
25,046
Culvert I Orifice Structures
Weir Structures
[A]
[B]
[C]
[PI'Marl
[A] [B]
[C]
[Dl
Rise (in) - 24.00
0.00
0.00
0.00
Crest Len (ft)
= 14.00 0.00
0.00
0.00
Span (in) = 24.00
0.00
0.00
0.00
Crest a. (ft)
= 248.00 0.00
0.00
0.00
No. Barrels = 1
0
0
0
Weir Coeff.
= 3.33 3.33
3.33
3.33
Invert El. (ft) = 242.00
0.00
0.00
0.00
Weir Type
= Riser -
--
--
Length (ft) - 50.00
0.00
0.00
0.00
Multistage
= Yes No
No
No
Slope (%) = 10.00
0.00
0.00
Na
N -Value = .013
.013
.013
n/a
Orifice Coeff. = 0.60
0.60
0.60
0.60
Exfil.(in/hr)
= 0.000 (by Contour)
Multistage = n/a
No
No
No
TW Elev. (ft)
= 0.00
Mole. Culver cWms are analyzed under Mtm (Ic) and audel (oc) oonbol Weir rfcros checked for orifice corWllWS (b:) and submer8enoe (s)
stage (ft)
Stage I
Discharge
Elev (ft)
2.00
249.00
1.80
248.80
1.60-
248.60
1.40
248.40
1 •20
248.20
1.00
248.00
0•80
247.80
0.60
247.60
0•ag
247.40
0.20
247.20
0•00
247.00
0.00 3.00 6.00 9.00 12.00
15.00
18.00
21.00 24.00 27.00
30.00
33.00
- Total 0
Discharge (cfs)

Channel Report
Hydraflow Express by InbeGsolve
Friday, Aug 2 2013
Temporary Diversion Behind Lots 31 -33 - Bare Soil
Triangular
Highlighted
Side Slopes (z:1)
= 3.00, 3.00
Depth (ft)
= 0.80
Total Depth (ft)
= 1.00
Q (cfs)
= 7.330
Area (sqft)
= 1.92
Invert Elev (ft)
= 100.00
Velocity (ftJs)
= 3.82
Slope ( %)
= 1.00
Wetted Perim (ft)
= 5.06
N -Value
= 0.020
Crit Depth, Yc (ft)
= 0.83
Top Width (ft)
= 4.80
Calculations
EGL (ft)
= 1.03
Compute by:
Known Q
Known Q (cfs)
= 7.33
Elev (ft)
102.00 =
101.50
101.00
100.50
145 I�
�l
Section
0 1 2 3 4 5 6 7 8
Reach (ft)
Depth (ft)
2.00
1.50
1.00
i
0.50
0.00
-0.50

Channel Report
Hydraflow Express by intellsoNe Friday, Aug 2 2013
Temporary Diversion Behind Lots 31 -33 - Vegetated
Triangular
Highlighted
Side Slopes (z:1)
= 3.00, 3.00
Depth (ft)
= 0.98
Total Depth (ft)
= 1.00
Q (cfs)
= 7.330
Area (sqft)
= 2.88
Invert Elev (ft)
= 100.00
Velocity (ft/s)
= 2.54
Slope ( %)
= 1.00
Wetted Perim (ft)
= 6.20
N -Value
= 0.035
Crit Depth, Yc (ft)
= 0.83
Top Width (ft)
= 5.88
Calculations
EGL (ft)
= 1.08
Compute by:
Known Q
Known Q (cfs)
= 7.33
Elev (ft)
102.00 —,
101.50
101.00
100.50
100.00
99.50
Section
D 1 2 3 4 5
Reach (ft)
6 7
Depth (ft)
2.00
1.50
1.00
0.50
0.00
L-- -0.50
8
i
i

Channel Report
Hydraflow Express by IntellsolVe Friday, Aug 2 2013
Temporary Diversion Along Road - Bare Soil
Triangular
Highlighted
Side Slopes (z:1)
= 3.00, 3.00
Depth (ft)
= 0.66
Total Depth (ft)
= 1.00
Q (ds)
= 12.28
Area (sgft)
= 1.31
Invert Elev (ft)
= 100.00
Velocity (ft/s)
= 9.40
Slope ( %)
= 8.00
Wetted Perim (ft)
= 4.17
N -Value
= 0.020
Crit Depth, Yc (ft)
= 1.00
Top Width (ft)
= 3.96
Calculations
EGL (ft)
= 2.03
Compute by:
Known Q
Known Q (cfs)
= 12.28
Elev (ft)
102.00
101.50
101.00
100.50
100.00
99.50
Section
1 2 3 4
Reach (ft)
5 6 7
Depth (ft)
2.00
1.50
1.00
0.50
0.00
1 -0.50
8

Channel Report
Hydraflow Express by Intermolve Friday, Aug 2 2013
Temporary Diversion Along Road - Vegetated
Triangular
Highlighted
Side Slopes (z:1)
= 3.00, 3.00
Depth (ft)
= 0.81
Total Depth (ft)
= 1.00
Q (cfs)
= 12.28
Area (sgft)
= 1.97
Invert Elev (ft)
= 100.00
Velocity (ftts)
= 6.24
Slope ( %)
= 8.00
Wetted Perim (ft)
= 5.12
N -Value
= 0.035
Crit Depth, Yc (ft)
= 1.00
Top Width (ft)
= 4.86
Calculations
EGL (ft)
= 1.42
Compute by:
Known Q
Known Q (cfs)
= 12.28
Elev (ft) Section
102.00
101.50
101.00
100.50
100.00
99.50
0 1 2 3 4 5 6 7 8
Reach (ft)
Depth (ft)
2.00
1.50
1.00
0.50
0.00
-0.50

Skimmer Sediment Basin Worksheet
(Drainage Area Must be Less Than 10 Acres)
Area Disturbed = 2.93 Acres
Runoff Area = 2.83 Acres
Q10 =CXIXA = .3Sx74x2 -S
_ 7 33 cfs
Basin Volume Calculation:
Volume of Sediment = ( 2 -83 Ac.) x (1800 cf sed. /year) x (1 year)
o cf
Assume Z foot of basin depth, therefore area of the pit Z—% Square Feet
Try ( 3& wide) x (Z long) x ( Z foot deep) Sediment Basin
Surface Area Calculation:
Surface Area (SF) = Qjo x 325 sf /cfs
7 33 x 325 sf/cfs
= 2 38 Z sf
= 2 Z '> Zf 3� Z Surface Area - e&
Use ( wide) x ( long) x ( foot deep) Sediment Basin
Surface Area —
Weir Design and Velocity Check:
Q10 = 7. 33 cfs; Q = CLH3'2; H = [Q /CL]2/3
_ [ 33 / (2.68)( g' )12/3
Z feet
Velocity Check 4 ( 7.33 )/( l5" ) ( 0.37- )= , $ fps, OK �/�

4W a `t 4sre $q
(=J
Skimmer Sediment Basin Worksheet
(Drainage Area Must be Less Than t0 Acres)
Area Disturbed = _ .�, g Acres
Runoff Area =_ 2. Acres
Qio = C x -I x A = .__3Sx _7.W x*.J?. tfZ.
=
21-01 cfs
Basin Volume Calculation:
Volume of Sediment = La. (o$ Ac.) x (1800 cf sed. /year) x (1 year)
cf
Assume .foot of basin depth, therefore area of the pit _ Square Feet
Try ( wide) x ( long) x ( - foo t deep).Sediment Basin
Surface Area Calculation:
Surface Area (SF) .= Qio x 325 sf /cfs
= 21.8!J x 325 sf /cfs
OS sf
ON ? j"N S u rf a ce. Area — oil
VISE f Z. 000 e F SM!p. -p6,e pt-Ad Use ( wide) x ( _ long) x (jam foot deep) Sediment Basin
=1� Surface Area — O
Mir Desinn and Velocity Chem
Q10 = Z!. Of cfs; Q = CLH312 ; H = [Q /CL]2r3
2�-- 1'$ f / (2.68)( qg )i"
_. 3 Z feet
Velocity Check 4 ( ?f.61 1/( ) (0•32- ) _ /. $2 fps, OK d3"A✓

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Engineer's Computation Pad
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Permit Number:
(to beprov(ded byDWQ)
Drainage Area Number.
Bioretention Operation and Maintenance Agreement
I will keep a maintenance record on this BMP. This maintenance record will be kept in a
log in a known set location. Any deficient BMF elements noted in the inspection will be
corrected, repaired or replaced immediately. These deficiencies can affect the integrity
of structures, safety of the public, and the removal efficiency of the BUR
Important operation and maintenance procedures:
- Immediately after the bioretention cell is established, the plants will be watered
twice weekly if needed until the plants become established (commonly six
weeks).
- Snow, mulch or any other material will NEVER be piled on the surface of the
bioretention cell.
- Heavy equipment will NEVER be driven over the bioretention cell.
- Special care will be taken to prevent sediment from entering the bioretention cell.
- Once a year, a soil test of the soil media will be conducted.
After the bioretention cell is established, I will inspect it once a month and within 24
hours after every storm event greater than 1.0 inches (or 1.5 inches if in a Coastal
County). Records of operation and maintenance will be kept in a known set location
and will be available upon request.
Inspection activities shall be performed as follows. Any problems that are found shall
be repaired immediately.
BMP element:
Potential problems:
How I will remediate the blew:
The entire BMP
Trash debris is present
Remove the trash debris.
The perimeter of the
bioretention cell
Areas of bare soil and /or
erosive gallies have formed.
Regrade the soil if necessary to
remove the gully, and then plant a
ground cover and water until it is
established. Provide lime and a
one -time fertilizer applkation.
The inlet device: pipe,
stone verge or swale
The pipe is clogged (if
a licable ).
Unclog the pipe. Dispose of the
sediment off -site.
The pipe is cracked or
otherwise damaged (if
Replace the pipe.
a likable).
Erosion is occurring in the
Swale (if applicable).
Regrade the Swale if necessary to
smooth it over and provide erosion
control devices such as reinforced
turf matting or riprap to avoid
future problems with erosion.
Stone verge is dogged or
covered in sediment (if
Remove sediment and clogged
scone and replace with dean stone .
applicable).
Form SW401 Bioretention O&M -Rev.3 Page 1 of 4

BMP element:
Potential problems:
How I will remedlate the problem:
The pretreatment area
Flow is bypassing
Regrade if necessary to route all
pretreatment area and /or
flow to the pretreatment area.
gullies have formed.
Restabilime the area after
Sediment has accumulated to
Search for the source of the
a depth greater than three
sediment and remedy the problem if
inches.
possible. Remove the sediment and
1 P1 labilize the pTebreat meirt area.
Erosion has occurred.
Provide additional erosion
protection such as reinforced turf
matting or Aprap if needed to
prevent future erosion problems,
Weeds are present.
Remove the weeds, preferably by
hand.
The bloretention cell:
vegetation
Best professional practices
show that pruning is needed
Prune according to best professional
practices.
to maintain optimal plant
health.
Plants are dead, diseased or
dying.
Determine the source of the
problem: soils, hydrology, disease,
etc. Remedy the problem and
replace plants. Provide a one -time
fertilizer application to establish the
ground cover if a soil test indicates
it is
Tree stakes /wires are present
Remove tree stake /wires (which
six months after planting.
can kill the tree if not removed ).
The bloretention cell:
souls and mulch
Mulch is breaking down or
has floated away.
Spot mulch if there are only random
void areas. Replace whole mulch
layer if necessary. Remove the
remaining much and replace with
triple shredded hard wood mulch at
a maximum depth of three inches.
Soils and /or mulch are
clogged with sediment.
Determine the extent of the clogging
- remove and replace either just the
top layers or the entire media as
needed. Dispose of the spoil in an
appropriate off -site location. Use
triple shredded hard wood mulch at
a maximum depth of three inches.
Search for the source of the
sediment and remedy the problem if
asible.
An annual soil test shows that
pH has dropped or heavy
Dolomitic lime shah be applied as
recommended per the soil test and
metals have accumulated in
toxic soils shall be removed,
the soil media.
disposed of properly and replaced
with new Lknhn media.
Form SW401 Hioretention O&M -Rev.3 Page 2 of 4

BMP element:
Potential Problems:
How Y will remediate the blew
The underdrain system
if a licable
clogging has occurred.
Wash out the underdrain system.
The drop Inlet
Clogging has occurred.
Clean out the drop inlet. Dispose of
the sediment off -site.
Thedrop inlet is damaged
Repair or replace the drop inlet.
The receiving water
Erosion or other signs of
Contact the NC Division of Water
damage have occurred at the
Quality 401 Oversight Unit at 919.
outlet.
733 -1786.
Form SW401- 13ioretedion O&M -Rev.3 Page 3 of 4

Permit Number.
(to be provided by DWQ)
acknowledge and agree by my signature below that I am responsible for the
performance of the maintenance procedures listed above. I agree to notify DWQ of any
problems with the system or prior to any changes to the system or responsible party.
Project name:Flowers Plantation Pod NW 8- Phase 2
BMW drainage area number:NA
Print name:Rebecca Flowers
Title:Owner / Developer
Address:4880 NC 42 East. Clayton, NC 27520
Note: The legally responsible party should not be a homeowners association unless more than 50'/0 of
the lots have been sold and a resident of the subdivision has been named the president.
I, //? a Notary Public for the State of
�a44. Cara 1; .,,c• , County of A A s (, , do hereby certify that
FA(o,e c r s F /a'.3 'r s personally appeared before me this 7
day of &G x + , 201 3. and ackmowledge the due execution of the
forgoing bioretention maintenance requirements. Witness my hand and official seal,
;00
JOIA 0-
.mot•, � ��
SEAL
My commission expires /-z / s
Form SW401- Bioreimfion I&M -Rev. 2 Page 4 of 4