20050732 Ver 21_Stormwater Info_20110701

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I TO: NCDENR - DWQ 401 Unit
512 N Salisbury Street
Archdale Building -91" Floor
Raleigh, NC 27604
ATTENTION: Ms. Annette Lucas
?5-?? 3a vas
DATE: June 22, 2011
PROJECT NO: 2735-0072 TASK NO: EXP
RE: Briar Chapel - Briar Chapel Parkway &
Boulder Point Drive Extensions
TRANSMITTAL NO: 1 PAGE 1 OF 1
LETTER OF TRANSMITTAL
WE ARE SENDING: ? Originals ® Prints ? Shop Drawings ? Samples
? Specifications ? Calculations ? Other -
Quantity Drawing No. Rev. Description Status
2 Stormwater Design Plans D-13, D-14, D-15 (Pond #8 only) G
2 Narrative & Supporting Calculations G
4 (2 ea) LSNFS #1 & #2 Design Supplements G
2 Originals LSNFS #1 & #2 O&M Agreements G
Issue Status Code:
REMARKS:
A. Preliminary B. Fabrication Only C. For Information D. Bid
E. Construction F. For Review & Comments G. For Approval H. See Remarks
Ms. Lucas,
Please find the enclosed documents for your review. Please let us know if you have any questions or
comments. Thank you.
1730 Varsity Drive, Suite 500 Raleigh, NC 27606 919/233-8091 Fax [phone]
Cc:
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JUL 0 1 2011
DENR •_ ft t* AL
Signed
avm3d-
McKIM & CREED, INC.
Gareth Avant, PE, LEED AP
Permit Number: 1) S- o 13 a. V 2(
(to be provided by DWQ)
Drainage Area Number:
Filter Strip, Restored Riparian Buffer and Level Spreader
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 BMP 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 BMP.
Important maintenance procedures:
- Immediately after the filter strip is established, any newly planted vegetation
will be watered twice weekly if needed until the plants become established
(commonly six weeks).
- Once a year, the filter strip will be reseeded to maintain a dense growth of
vegetation
- Stable groundcover will be maintained in the drainage area to reduce the
sediment load to the vegetation.
- Two to three times a year, grass filter strips will be mowed and the clippings
harvested to promote the growth of thick vegetation with optimum pollutant
removal efficiency. Turf grass should not be cut shorter than 3 to 5 inches and
may be allowed to grow as tall as 12 inches depending on aesthetic requirements
(NIPC,1993). Forested filter strips do not require this type of maintenance.
- Once a year, the soil will be aerated if necessary.
- Once a year, soil pH will be tested and lime will be added if necessary.
After the filter strip is established, it will be inspected quarterly and within 24 hours
after every storm event greater than 1.0 inch (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 problem: How I will rernediate the problem:
The entire filter strip Trash/ debris is present. Remove the trash/ debris.
system
The flow splitter device The flow splitter device is Unclog the conveyance and dispose
(if applicable) clogged. of an sediment off-site.
The flow splitter device is Make any necessary repairs or
damaged. replace if damage is too large for
repair.
Form SWU401-Level Spreader, Filter Strip, Restored Riparian Buffer O&M-Rev-3 Page 1 of 3
BMP element: Potential problem: How I will remediate the problem:
The swale and the level The swale is clogged with Remove the sediment and dispose
lip sediment. of it off-site.
The level lip is cracked, Repair or replace lip.
settled, undercut, eroded or
otherwise damaged.
There is erosion around the Regrade the soil to create a berm
end of the level spreader that that is higher than the level lip, and
shows stormwater has then plant a ground cover and
bypassed it. water until it is established. Provide
lime and a one-time fertilizer
application.
Trees or shrubs have begun Remove them.
to grow on the swale or just
downslo e of the level lip.
The bypass channel Areas of bare soil and/or Regrade the soil if necessary to
erosive gullies have formed. remove the gully, and then
reestablish proper erosion control
Turf reinforcement is Study the site to see if a larger
damaged or ripap is rolling bypass channel is needed (enlarge if
downhill. necessary). After this, reestablish
the erosion control material.
The filter strip Grass is too short or too long Maintain grass at a height of
(if applicable). approximately three to six inches.
Areas of bare soil and/or Regrade the soil if necessary to
erosive gullies have formed. remove the gully, and then plant a
ground cover and water until it is
established. Provide lime and a
one-time fertilizer application.
Sediment is building up on Remove the sediment and
the filter strip. restabilize the soil with vegetation if
necessary. Provide lime and a one-
time fertilizer application.
Plants are desiccated. Provide additional irrigation and
fertilizer as needed.
Plants are dead, diseased or Determine the source of the
dying. problem: soils, hydrology, disease,
etc. Remedy the problem and
replace plants. Provide a one-time
fertilizer application.
Nuisance vegetation is Remove vegetation by hand if
choking out desirable species. possible. If pesticide is used, do not
allow it to get into the receiving
water.
The receiving water Erosion or other signs of Contact the NC Division of Water
damage have occurred at the Quality local Regional Office, or the
outlet. 401 Oversight Unit at 919-733-1786.
Form SWU401-Level Spreader, Filter Strip, Restored Riparian Buffer O&M-Rev.3 Page 2 of 3
Permit Number:
(to be provided by DWQ)
I 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:Briar Chapel - Briar Chapel Parkway and Boulder Point Drive Extensions
BMP drainage area number:#2 - LS/VFS #2
Print name: William S Mumford
Title:Assistant Vice President
Address: 16 Windy Knoll Circle, Chapel Hill, NC 27516
Phone: [phone]""700
Signature:
Date: w •Z$ -`tv i
Note: The legally responsible party should not be a homeowners association unless more than 50% of
the lots have been sold and a resident of the subdivision has been named the president.
Guniia w • a Notary Public for the State of
N? ?kl?l Cka'o Li hC,J , County of QeC?LJen? ,ra , do hereby certify that
w tCCn S m urnCa&I personally appeared before me this ?,-t f?j
day of 1? a olk , and acknowledge the due execution of the
forgoing filter strip, riparian buffer, and/or level spreader maintenance requirements.
Witness my hand and official seal,
SEAL
My commission expires 3.19 -1'L
Form SWU401-Level Spreader, Filter Strip, Restored Riparian Buffer O&M-Rev.3 Page 3 of 3
Permit Number: D 5 r 013 a. U Z t
(to be provided by DWQ)
Drainage Area Number:
Filter Strip, Restored Riparian Buffer and Level Spreader
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 BMP 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 BMP.
Important maintenance procedures:
- Immediately after the filter strip is established, any newly planted vegetation
will be watered twice weekly if needed until the plants become established
(commonly six weeks).
- Once a year, the filter strip will be reseeded to maintain a dense growth of
vegetation
- Stable groundcover will be maintained in the drainage area to reduce the
sediment load to the vegetation.
- Two to three times a year, grass filter strips will be mowed and the clippings
harvested to promote the growth of thick vegetation with optimum pollutant
removal efficiency. Turf grass should not be cut shorter than 3 to 5 inches and
may be allowed to grow as tall as 12 inches depending on aesthetic requirements
(NIPC,1993). Forested filter strips do not require this type of maintenance.
- Once a year, the soil will be aerated if necessary.
- Once a year, soil pH will be tested and lime will be added if necessary.
After the filter strip is established, it will be inspected quarterly and within 24 hours
after every storm event greater than 1.0 inch (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 problem: How I will remediate the problem:
The entire filter strip Trash/debris is present. Remove the trash/ debris.
system
The flow splitter device The flow splitter device is Unclog the conveyance and dispose
(if applicable) clogged. of an sediment off-site.
The flow splitter device is Make any necessary repairs or
damaged. replace if damage is too large for
repair.
Form SWU401-Level Spreader, Filter Strip, Restored Riparian Buffer O&M-Rev.3 Page 1 of 3
BMP element: Potential problem: How I will remediate the problem:
The swale and the level The swale is clogged with Remove the sediment and dispose
lip sediment. of it off-site.
The level lip is cracked, Repair or replace lip.
settled, undercut, eroded or
otherwise damaged.
There is erosion around the Regrade the soil to create a berm
end of the level spreader that that is higher than the level lip, and
shows stormwater has then plant a ground cover and
bypassed it. water until it is established. Provide
lime and a one-time fertilizer
application.
Trees or shrubs have begun Remove them.
to grow on the swale or just
downslo e of the level lip.
The bypass channel Areas of bare soil and/or Regrade the soil if necessary to
erosive gullies have formed. remove the gully, and then
reestablish roper erosion control.
Turf reinforcement is Study the site to see if a larger
damaged or ripap is rolling bypass channel is needed (enlarge if
downhill. necessary). After this, reestablish
the erosion control material.
The filter strip Grass is too short or too long Maintain grass at a height of
if applicable). approximately three to six inches.
Areas of bare soil and/or Regrade the soil if necessary to
erosive gullies have formed. remove the gully, and then plant a
ground cover and water until it is
established. Provide lime and a
one-time fertilizer application.
Sediment is building up on Remove the sediment and
the filter strip. restabilize the soil with vegetation if
necessary. Provide lime and a one-
time fertilizer application.
Plants are desiccated. Provide additional irrigation and
fertilizer as needed.
Plants are dead, diseased or Determine the source of the
dying. problem: soils, hydrology, disease,
etc. Remedy the problem and
replace plants. Provide a one-time
fertilizer application.
Nuisance vegetation is Remove vegetation by hand if
choking out desirable species. possible. If pesticide is used, do not
allow it to get into the receiving
water.
The receiving water Erosion or other signs of Contact the NC Division of Water
damage have occurred at the Quality local Regional Office, or the
outlet. 401 Oversight Unit at 919-733-1786.
Form SWU401-Level Spreader, Filter Strip, Restored Riparian Buffer O&M-Rev.3 Page 2 of 3
Permit Number:
(to be provided by DWQ)
I 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:Briar Chapel - Briar Chapel Parkway and Boulder Point Drive Extensions
BMP drainage area number:#1 - LS/VFS #1
Print name:William S Mumford
Title:Assistant Vice President
Address: 16 Windy Knoll Circle, Chapel Hill, NC 27516
Phone: [phone]
Signature:
Date: 60-L6-ZOO) y
Note: The legally responsible party should not be a homeowners association unless more than 50% of
the lots have been sold and a resident of the subdivision has been named the president.
I, Geoygq-,c, Lo- hAmon , a Notary Public for the State of
IJ OAA-, Can l,nc,.. , County of "eC k lun 6,, z, , do hereby certify that
W' I [i C'_M S m m ? personally appeared before me this
day of tTi?,lne> o? , and acknowledge the due execution of the
forgoing filter strip, riparian buffer, and/or level spreader maintenance requirements.
Witness my hand and official seal,
SEAL
My commission expires 3-lb-t2-
Form SWU401-Level Spreader, Filter Strip, Restored Riparian Buffer O&M-Rev.3 Page 3 of 3

C) S - o '13 -a- u 2-1
t 401 NARRATIVE AND
SUPPORTING CALCULATIONS
Briar Chapel Development
' Briar Chapel Parkway & Boulder Point Drive Extensions
Chatham County, North Carolina
' June 22, 2011
Prepared for: Ju
' ?NR ' wA
BRIAR CHAPEL"
' Newland COMMUNITIES

NNP Briar Chapel, LLC
16 Windy Knoll Circle
Chapel Hill, North Carolina 27516
Prepared By:
M44??MCKIM&CREED
1730 Varsity Drive, Suite 500
Raleigh, North Carolina 27606
Phone: [phone]
Fax: [phone]
M&C Project No. 02735-0069
N CARS 1'
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SEAL -
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PROJECT DESCRIPITON
The purpose of the project is to construct Briar Chapel Parkway and Boulder Point Drive from
their current terminus points within the development to their intersection.
The extension of Briar Chapel Parkway will include: (a) approximately 1,740 If of a 2-lane divided
section of 14' asphalt pavement with 30" wide curb and gutter, generally separated by a 40'
vegetated median, though the median width is variable; (b) approximately 1,440 If of a 2-lane,
undivided 30' wide section of asphalt pavement with 30" curb and gutter.
The extension of Boulder Point Drive will include approximately 1,660 If of 22' wide asphalt
pavement with 30" curb and gutter.
Upon completion of the project's construction, the proposed public roads will be turned over to
and maintained by NCDOT.
SITE DESCRIPTION
The project limits are an approximately 13 acre area. The project can be reached by traveling
along Briar Chapel Parkway approximately two miles west of its intersection with US 15-501, or by
entering Granite Mill Boulevard from Andrews Store road and continuing along Boulder Point
Drive to its current terminus near the end of the existing school project.
The site was previously cleared and grubbed and approved erosion control measures were
installed under separate land disturbing permit.
Due to the linear nature of the project, the roadways will run nearby several perennial and
intermittent streams and areas of wetlands as identified through previous site studies. No stream,
stream buffer or wetland will be impacted by the development of this project. These areas are
eventual tributaries to Pokeberry Creek (WS-IV; NSW).
The project area has rolling terrain where the highest existing elevation is approximately 544' MSL
and the lowest is 500' MSL. Slopes range from 27o to 15% in localized areas.
SOILS
According to the Chatham County Generalized Soil Survey, the soils within the project area are
classified as Wedowee sandy loam, 2% to 15% slopes (WeB, WeC, WeD) and bouldery WdC, 2%
to 15% slopes. (WdC). The bouldery slopes are found along the Boulder Point Drive Extension.
The following soil descriptions are associated with the soils found on the site:
We(X), WdC - Wedowee sandy loam soils are often found in piedmont uplands, along
ridges and side slopes. Permeability is moderate and the soils are well drained. Soils have
a low shrink/swell potential. The seasonal high water is generally more than 6.0 feet
below the surface.

PLANNED STORMWATER MANAGEMENT PRACTICES
'
BRIAR CHAPEL PARKWAY:
Under an existing permit, the 401 Unit approved a portion of Briar Chapel Parkway as a low
' density project, and a portion to be temporarily low density until future residential phases would
be built to treat and control that runoff. The original permit was obtained by the John R.
' McAdams Company under the original Phase 5 N permit number EXP 05-0732v8.
Since this area has already been permitted and the roadway sections/impervious numbers have
remained relatively the same, we are proposing to utilize the same measures.
' Runoff upstream of FES #60 (Sheet C-6) will be re-routed into Phase 6 South's stormwater system
once that project begins. Temporarily, an appropriately sized scour hole will be used to dissipate
' the energy and provide diffuse flow downstream. FES #35 and #40 will be permanent scour
holes to be maintained by the developer
.
BOULDER POINT DRIVE:
'
As a result of preliminary discussions with DWQ, Boulder Point Drive will be proposed as a
temporary low density area. Since this area was not previously permitted, the runoff will be
treated using currently accepted methods established by the NC BMP Manual. Level
spreader/vegetated filter strips will be constructed to treat the runoff from the 1 " storm. As
residential areas are constructed in the locations of these devices, they will be removed and
stormwater will be re-directed into other BMPs that will be designed at that time.

STORMWATER CALCULATIONS
' Water quality flows were calculated using methods provided in the NC BMP Manual. For
proposed engineered level spreader/vegetated filter strip devices, a 1 in/hr rainfall would
' produce the following flows:
LS/VFS # 1 1.27 cfs
LS/VFS #2 1.16 cfs
"
'
Using culvert modeling software, these flows produced flow depth in 6
PVC conduit of 0.49
(LS/VFS # 1) and 0.32' (LS/VFS #2). In order to isolate the water quality runoff from larger flows,
the smaller outlet pipe was set at a lower elevation equal to the flow depths in the conduit. For
' example, the bypass outlet for SDMH # 1 is set at elevation 494.00 whereas the 6" outlet to the
level spreader forebay is set at elevation 493.50. Once the flow is greater than 1.27 cfs, the
water will flow into the bypass pipe.
MAINTENANCE CONSIDERATIONS
' The property owner shall be responsible for periodic inspection and maintenance of all
permanent BMP Devices. Any measure that fails to function as intended shall be repaired
immediately.

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1 CALCULATIONS

Culvert Calculator Report
Flow Splitter SDMH #1
' Solve For: Headwater Elevation
C
l
u
vert Summary
Allowable HW Elevation 501.01 ft Headwater Depth/Height 10.86
Computed Headwater Elevation 498.93 ft Discharge 1.27 cfs
Inlet Control HW Elev. 495.50 ft Tailwater Elevation 0.00 ft
Outlet Control HW Elev. 498.93 ft Control Type Outlet Control
'
Grades
Upstream Invert 493.50 ft Downstream Invert 492
00 ft
' Length 180.00 ft Constructed Slope .
0.008333 ft/ft
Hydraulic Profile
' Profile CompositeM2Pressure Profile Depth, Downstream 0.49 ft
Slope Type Mild Normal Depth N/A ft
' Flow Regime
Velocity Downstream Subcritical
6.51 ft/s Critical Depth
Critical Slope 0.49 ft
0.027002 ft/ft

' Section
Section Shape Circular Mannings Coefficient 0.010
Section Material PVC Span 0.50 ft
Section Size 6 inch Rise 0.50 ft
' Number Sections 1
Outlet Control Properties
' Outlet Control HW Elev. 498.93 ft Upstream Velocity Head 0.65 ft
Ke 0.50 Entrance Loss 0.33 ft
Inlet Control Properties
Inlet Control HW Elev. 495.50 ft Flow Control Submerged
' Inlet Type Square edge w/headwall Area Full 0.2 ft2
K 0.00980 HDS 5 Chart 1
M 2.00000 HDS 5 Scale 1
C 0.03980 Equation Form 1

1 Y 0.67000

untitled.cvm
McKim & Creed Raleigh Master Project Engineer: gavant
CulvertMaster v3.2 [03.02.00.01 ]
' 06/22/11 04:19:50 PMO Bentley Systems, Inc. Haestad Methods Solution Center Watertown, CT 06795 USA [phone] Page 1

Culvert Calculator Report
' Flow Splitter SDMH #2
Solve For: Headwater Elevation
' C
l
t S
u
ver
ummary
Allowable HW Elevation 513.99 It Headwater Depth/Height 3.42
Computed Headwater Elevation 510.14 ft Discharge 1.16 cis
' Inlet Control HW Elev. 510.14 ft Tailwater Elevation 0.00 It
Outlet Control HW Elev. 509.74 ft Control Type Inlet Control
'
Grades
Upstream Invert 508.43 ft Downstream Invert 506.00 ft
' Length 51.00 ft Constructed Slope 0.047647 ft/ft
' Hydraulic Profile
Profile S2 Depth, Downstream 0.32 ft
Slope Type Steep Normal Depth 0.32 ft
' Flow Regime
Velocity Downstream Supercritical
8.82 ft/s Critical Depth
Critical Slope 0.48 it
0.022211 ft/ft

' Section
Section Shape Circular Mannings Coefficient 0.010
Section Material PVC Span 0.50 ft
Section Size 6 inch Rise 0.50 It
' Number Sections 1
Outlet Control Properties
' Outlet Control HW Elev. 509.74 ft Upstream Velocity Head 0.55 ft
Ke 0.50 Entrance Loss 0.28 ft
' Inlet Control Properties
Inlet Control HW Elev. 510.14 ft Flow Control Submerged
Inlet Type Square edge w/headwall Area Full 0.2 ft'
' K 0.00980 HDS 5 Chart 1
M 2.00000 HDS 5 Scale 1
C 0.03980 Equation Form 1
' Y 0.67000

untitled.cvm
McKim & Creed Raleigh Master Project Engineer: gavant
CulvertMaster v3.2 [03.02.00.01 ]
' 06/22/11 04:19:50 PM© Bentley Systems, Inc. Haestad Methods Solution Center Watertown, CT 06795 USA [phone] Page 2

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NCDENR `
STORMWATER MANAGEMENT PERMIT APPLICATION FORM
401 CERTIFICATION APPLICATION FORM
LEVEL SPREADER - VEGETATED FILTER STRIP (LS-VFS) SUPPLEMENT
This form must be completely filled out, printed, initialed, and submitted.
I. PROJECT INFORMATION
Project name Briar Chapel Development - BC Parkway & Boulder Point Drive Extensions
Contact name Grant Livengood
Phone number 919.233.8091
Date June 22, 2011
Drainage area number #1
11. DESIGN INFORMATION
The purpose of the LS-VFS Pollutant removal: 40% TSS, 30% TN, 35% TP
Stormwater enters LS-VFS from The drainage area
Type of VFS Engineered filter strip (graded & sodded, slope < 8%)
Explanation of any "Other" responses above
If Stormwater Enters the LS-VFS from the Drainage Area
Drainage area 69,061 ftz
Impervious surface area 35,939 ft2
Percent impervious 52.04 %
Rational C coefficient 0.80
Peak flow from the 1 in/hr storm 1.27 cfs
Time of concentration 5.00 min
Rainfall intensity, 10-yr storm 7.38 in/hr
Peak flow from the 10-yr storm 9.36 cfs
Design storm 1 inch/hour storm
Maximum amount of flow directed to the LS-VFS 1.27 cfs
Is a flow bypass system going to be used? Y (Y or
Explanation of any "Other" responses above
If Stormwater Enters the LS-VFS from a BMP
Type of BMP
Peak discharge from the BMP during the design storm
Peak discharge from the BMP during the 10-year storm
Maximum capacity of a 100-foot long LS-VFS
Peak flow directed to the LS-VFS
Is a flow bypass system going to be used?
Explanation of any "Other" responses above
LS-VFS Design
Pick one:
Do not complete this section of the form.
cfs
cfs Do not complete this section of the form.
10 cfs
cfs Do not complete this section of the form.
(Y or N)
Forebay surface area 378 sq ft Forebay is adequately sized.
Depth of forebay at stormwater entry point 24 in Depth is appropriate.
Depth of forebay at stormwater exit point 6 in Depth is appropriate.
Feet of level lip needed per cfs 10 ft/cfs
Computed minimum length of the level lip needed 13 ft
Form SW401 - LS-VFS - 29Nov2010 - Rev.8
page 1 of 3
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Length of level lip provided
Width of VFS
Elevation at downslope base of level lip
Elevation at the end of the VFS that is farthest from the LS
Slope (from level lip to the end of the VFS)
Are any draws present in the VFS?
Is there a collector swale at the end of the VFS?
Bypass System Design (if applicable)
Is a bypass system provided?
Is there an engineered flow splitting device?
Dimensions of the channel (see diagram below):
M
B
W
y (flow depth for 10-year storm)
freeboard (during the 10-year storm)
Peak velocity in the channel during the 10-yr storm
Channel lining material
Does the bypass discharge through a wetland?
Does the channel enter the stream at an angle?
Explanation of any "Other" responses above
50 ft
30 ft
492.25 fmsl
490.75 fmsl
5.00 %
N (Y or N) OK
Y (Y or N)
Y (Y or N)
Y (Y or N) Please provide plan details of flow splitter & supporting calcs.
ft
ft
ft
ft
9.16 fUsec
Pick one:
N (Y or N)
Y (Y or N)
NV
?t V
? B
111. REQUIRED ITEMS CHECKLIST
EDIT 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 information. 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.
Requried Item:
1. Plans (1" - 50' or larger) of the entire site showing:
- Design at ultimate build-out,
Off-site drainage (if applicable),
Delineated drainage basins (include Rational C coefficient per basin),
Forebay (if applicable),
High flow bypass system,
Maintenance access,
Proposed drainage easement and public right of way (ROW), and
Boundaries of drainage easement.
Initials Page or plan sheet number and any notes:
C-5 &-C-6
Form SW401 - LS-VFS - 29Nov2010 - Rev.8
page 2 of 3

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2. Plan details (1" = 30' or larger) for the level spreader showing:
- Forebay (if applicable),
High flow bypass system,
One foot topo lines between the level lip and top of stream bank,
Proposed drainage easement, and
Design at ultimate build-out.
3. Section view of the level spreader (1" = 20' or larger) showing:
- Underdrain system (if applicable),
Level lip,
Upslope channel, and
Downslope filter fabric.
4. Plan details of the flow splitting device and supporting calculations (if applicable)
5. A construction sequence that shows how the level spreader will be protected from
sediment until the entire drainage area is stabilized.
6. If a non-engineered VFS is being used, then provide a photograph of the VFS showing
that no draws are present.
7. The supporting calculations.
8. A copy of the signed and notarized operation and maintenance (0&M) agreement.
Form SW401 - LS-VFS - 29Nov2010 - Rev.8
D-8
D-8
D-8/Narrative & calculation booklet
NIA
Narrative & calculations booklet
Included
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?? O??F W ATFROG
NCDENR
STORMWATER MANAGEMENT PERMIT APPLICATION FORM
' 401 CER TIFICATION APPLICATION FORM
LEVEL SPREADER - VEGETATED FILTER STRIP (LS-VFS) SUPPLEMENT
' This form must be completely filled out, printed, initialed, and submitted.
!. PROJECT INFORMATION
Project name Briar Chapel Development - BC Parkway & Boulder Point Drive Extensions
' Contact name Grant Livengood
Phone number 919.233.8091
Date June 22, 2011
' Drainage area number #2
II. DESIGN INFORMATION
The purpose of the LS-VFS Pollutant removal: 40% TSS, 30% TN, 35%a TP
' Stormwater enters LS-VFS from The drainage area
Type of VFS Engineered filter strip (graded & sodded, slope < 8%)
' Explanation of any "Other" responses above
If Stormwater Enters the LS-VFS from the Drainage Area
Drainage area 63,133 ft2
Impervious surface area 30,484 ft2
Percent impervious 48.29 %
Rational C coefficient 0.80
1 Peak flow from the 1 in/hr storm 1.16 cfs
Time of concentration 5.00 min
Rainfall intensity, 10-yr storm 7.38 in/hr
Peak flow from the 10-yr storm 8.56 cfs
' Design storm 1 inch/hour storm
Maximum amount of flow directed to the LS-VFS 1.16 cfs
Is a flow bypass system going to be used? Y (Y or N)
' Explanation of any "Other" responses above
' If Stormwater Enters the LS-VFS from a BMP Do not complete this section of the form.
Type of BMP Pick one:
Peak discharge from the BMP during the design storm cfs
Peak discharge from the BMP during the 10-year storm cfs Do not complete this section of the form.
' Maximum capacity of a 100-foot long LS-VFS 10 cfs
Peak flow directed to the LS-VFS cfs Do not complete this section of the form.
Is a flow bypass system going to be used? (Y or N)
' Explanation of any "Other" responses above
LS-VFS Design
Forebay surface area 379 sq ft Forebay is adequately sized.
Depth of forebay at stormwater entry point 24 in Depth is appropriate.
Depth of forebay at stormwater exit point 6 in Depth is appropriate.
' Feet of level lip needed per cfs 10 ft/cfs
Computed minimum length of the level lip needed 12 ft
Form SW401 - LS-VFS - 29Nov2010 - Rev.8
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Length of level lip provided
Width of VFS
Elevation at downslope base of level lip
Elevation at the end of the VFS that is farthest from the LS
Slope (from level lip to the end of the VFS)
Are any draws present in the VFS?
Is there a collector swale at the end of the VFS?
Bypass System Design (if applicable)
Is a bypass system provided?
Is there an engineered flow splitting device?
Dimensions of the channel (see diagram below):
M
B
W
y (flow depth for 10-year storm)
freeboard (during the 10-year storm)
Peak velocity in the channel during the 10-yr storm
Channel lining material
Does the bypass discharge through a wetland?
Does the channel enter the stream at an angle?
Explanation of any "Other' responses above
50 ft
30 ft
508.25 fmsl
506.75 fmsl
5.00 %
N (Y or N) OK
Y (Y or N)
Y (Y or N)
Y (Y or N) Please provide plan details of flow splitter & supporting calcs.
ft
ft
ft
ft
8.16 ft/sec
Pick one:
N (Y or N)
Y (Y or N)
NV
+ B
III. REQUIRED ITEMS CHECKLIST
EDIT 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 information. 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.
Requried Item: Initials
1. Plans (1" - 50' or larger) of the entire site showing:
- Design at ultimate build-out,
Off-site drainage (if applicable),
Delineated drainage basins (include Rational C coefficient per basin),
Forebay (if applicable),
High flow bypass system,
Maintenance access,
Proposed drainage easement and public right of way (ROW), and
- Boundaries of drainage easement.
Form SW401 - LS-VFS - 29Nov2010 - Rev.8
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2. Plan details (1" = 30' or larger) for the level spreader showing:
- Forebay (if applicable),
High flow bypass system,
One foot topo lines between the level lip and top of stream bank,
Proposed drainage easement, and
Design at ultimate build-out.
3. Section view of the level spreader (1" = 20' or larger) showing:
- Underdrain system (if applicable),
Level lip,
Upslope channel, and
Downslope filter fabric.
4. Plan details of the flow splitting device and supporting calculations (if applicable)
5. A construction sequence that shows how the level spreader will be protected from
sediment until the entire drainage area is stabilized.
6. If a non-engineered VFS is being used, then provide a photograph of the VFS showing
that no draws are present.
7. The supporting calculations.
8. A copy of the signed and notarized operation and maintenance (08M) agreement.
Form SW401 - LS-VFS - 29Nov2010 - Rev.8
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