20050732 Ver 30_More Info Received_20150709

Strickland, Bev
From: Devane, Boyd
Sent: Thursday, July 09, 2015 2:04 PM
To: Strickland, Bev
Subject: Briar Chapel - Boulder Point Dr. BMP #18 - #05 -0732 v30
From: Gareth Avant [mailto:GAvant @mckimcreed.com]
Sent: Wednesday, July 08, 2015 3:55 PM
To: Devane, Boyd
Subject: RE: Approval of modifications to BMP #18 - #05 -0732 v30
MV
10011101
From: Devane, Boyd rmailto :bovd.devane(d)ncdenr.gov]
Sent: Wednesday, July 08, 2015 1:31 PM
To: Gareth Avant
Subject: RE: Approval of modifications to BMP #18 - #05 -0732 v30
From: Gareth Avant rmailto :GAvantCa)mckimcreed.comI
Sent: Wednesday, July 08, 2015 11:42 AM
To: Devane, Boyd
Subject: RE: Approval of modifications to BMP #18 - #05 -0732 v30
wi
Also, per your previous email, I can update our narrative as necessary to remove the "maximum extent practicable"
language.
1111 :71"11111v
From: Devane, Boyd rmailto :bovd.devane(d)ncdenr.gov]
Sent: Wednesday, July 08, 2015 11:38 AM
To: Gareth Avant
Subject: RE: Approval of modifications to BMP #18 - #05 -0732 v30

I'm trying to figure out what "new proposed deve|opment istobe treated by the scour hole? |s the .45 acre of
impervious footprint the proposed road on the western side? |s that the "new proposed deve|opment" that is under the
"Project Description" I assume that it is the drainage of the new road that does not drain into bioretention #20. If not,
where is this impervious located?
From: Gareth Avant [nlaiKo:GAvant()nlcknlcreed.conU
Sent: Wednesday, 3uh08, 20159:22AM
To: Oevane,Boyd
Subject: RE: Approval nf modifications toBMP #18-#05-07]2v]0
Per our conversation yesterday, in the western drainage basin, we have a total drainage area of approximately 3.6 acres
and an impervious footprint ofO.45acres.
From: Oevane, Boyd [nlaiKo:boyd.devane(d)ncdencoovl
Sent: Tuesday, 3uh07, 2015 10:12 AM
To: Gareth Avant
Subject: RE: Approval nf modifications toBMP #18-#05-07]2v]0
From: Gareth Avant [nlaiKo:GAvant()nlcknlcreed.conU
Sent: Monday, ]uh06,]0159:5OAM
To: Oevane,Boyd
Subject: RE: Approval nf modifications toBMP #18-#05-07]2v]0
| just wanted to follow up with you onthis. |fat all possible, vve are needing the approval for Boulder Point Drive this
week in order to meet the County's submittal deadline.
From: Oevane, Boyd [nlaiKo:boyd.devane(d)ncdencoovl
Sent: Friday, ]une26, 2015 11:39 AM
To: Gareth Avant
Subject: RE: Approval nf modifications toBMP #18-#05-07]2v]0

I'm leaving now. I will try to get it done on the 7t" when I come back. Send me an email that morning to remind me that
it's a priority.
From: Gareth Avant rmailto :GAvantCa)mckimcreed.com]
Sent: Friday, June 26, 2015 11:09 AM
To: Devane, Boyd
Subject: RE: Approval of modifications to BMP #18 - #05 -0732 v30
Also, we sent a package to you earlier this week for a new residential area at Briar Chapel, Phase 15 North. I got
notification that it was delivered. Please let me know if you haven't received that or if you need any additional
information.
From: Devane, Boyd rmailto :bovd.devane(d)ncdenr.gov]
Sent: Friday, June 26, 2015 8:52 AM
To: Gareth Avant
Subject: RE: Approval of modifications to BMP #18 - #05 -0732 v30
I might can get the other one out today but I can't guarantee it. If not, I should be able to get it soon after I return on
July 7t ". I didn't see anything wrong on my initial review.
From: Gareth Avant rmailto :GAvantCa)mckimcreed.com]
Sent: Friday, June 26, 2015 8:42 AM
To: Devane, Boyd
Cc: Smith, Cherri L; Robinson, Jason
Subject: RE: Approval of modifications to BMP #18 - #05 -0732 v30
' =
From: Devane, Boyd rmailto :bovd.devane(d)ncdenr.gov]
Sent: Thursday, June 25, 2015 3:04 PM
To: Gareth Avant
Cc: Smith, Cherri L; Robinson, Jason
Subject: Approval of modifications to BMP #18 - #05 -0732 v30
Please accept this note as the 401 and Buffer Permitting Unit's approval of the modifications to the Briar Chapel — SD
Commercial Stormwater Plan as was originally approved on February 27, 2015. This approval is for the changes that are
described in the " Stormwater Design Plans- REVISED ", the "Supporting Calculations- REVISED" and the "BMP Design
Supplement" that were received in our offices on June 10, 2015. If any other changes are proposed from these

approved today or those approved in February, the modified plans would need prior written authorization from the
Division.
This e -mail and any files transmitted with it are confidential
and intended solely for the use of the individual or entity to
whom they are addressed. If you have received this e -mail in
error please notify the system manager. Please note that any
views or opinions presented in this e -mail are solely those of
the author and do not necessarily represent those of the
company. Finally, the recipient should check this e -mail and
any attachments for the presence of viruses. The company
accepts no liability for any damage caused by any virus
transmitted by this e -mail.
This e -mail and any files transmitted with it are confidential
and intended solely for the use of the individual or entity to
whom they are addressed. If you have received this e -mail in
error please notify the system manager. Please note that any
views or opinions presented in this e -mail are solely those of
the author and do not necessarily represent those of the
company. Finally, the recipient should check this e -mail and
any attachments for the presence of viruses. The company
accepts no liability for any damage caused by any virus
transmitted by this e -mail.
This e -mail and any files transmitted with it are confidential
and intended solely for the use of the individual or entity to
whom they are addressed. If you have received this e -mail in
error please notify the system manager. Please note that any
views or opinions presented in this e -mail are solely those of
the author and do not necessarily represent those of the
company. Finally, the recipient should check this e -mail and
any attachments for the presence of viruses. The company
accepts no liability for any damage caused by any virus
transmitted by this e -mail.
This e -mail and any files transmitted with it are confidential
and intended solely for the use of the individual or entity to
whom they are addressed. If you have received this e -mail in
error please notify the system manager. Please note that any
views or opinions presented in this e -mail are solely those of
the author and do not necessarily represent those of the
company. Finally, the recipient should check this e -mail and
any attachments for the presence of viruses. The company
accepts no liability for any damage caused by any virus
transmitted by this e -mail.
This e -mail and any files transmitted with it are confidential
and intended solely for the use of the individual or entity to
whom they are addressed. If you have received this e -mail in
4

error please notify the system manager. Please note that any
views or opinions presented in this e -mail are solely those of
the author and do not necessarily represent those of the
company. Finally, the recipient should check this e -mail and
any attachments for the presence of viruses. The company
accepts no liability for any damage caused by any virus
transmitted by this e -mail.
This e -mail and any files transmitted with it are confidential
and intended solely for the use of the individual or entity to
whom they are addressed. If you have received this e -mail in
error please notify the system manager. Please note that any
views or opinions presented in this e -mail are solely those of
the author and do not necessarily represent those of the
company. Finally, the recipient should check this e -mail and
any attachments for the presence of viruses. The company
accepts no liability for any damage caused by any virus
transmitted by this e -mail.
5

401 NARRATIVE &
SUPPORTING CALCULATIONS
Briar Chapel Development
Boulder Point Drive Extension
Chatham County, North Carolina
July 8, 2015
Prepared for:
BRIAR_ V7CHAPEC
by
Newland COMMUNITIES
NNP Briar Chapel, LLC
16 Windy Knoll Circle
Chapel Hill, North Carolina 27516
Prepared By:
vJ MCKIM&CREED
1730 Varsity Drive, Suite 500
Raleigh, North Carolina 27606
Phone: [phone]
Fax: [phone]
M &C Project No. 02735-0113
.•Q�pFESS10�' •.9 '.
03 348 -
Gi'., OMM2015 =rte

PROJECT DESCRIPTION
The purpose of the project is to construct stormwater management and roadway infrastructure
to support future development within the western area of the Briar Chapel development.
Based on the conditions of the approved 401 Water Quality Certification, NCDENR -DWQ will
require runoff from the roads and impervious surfaces to be captured and treated for 85% TSS
removal before being discharged into existing stream buffers. To meet this requirement, the
runoff from the current and future development within the eastern portion of the project will be
captured and directed into Bioretention #20. The western portion of the site, due to its relatively
small impervious area will bypass all offsite drainage through the project area and direct runoff
generated from the new proposed development into a scour hole, where it will be dissipated
and directed offsite as diffuse flow. Future development from the extension of Boulder Point
Drive will be captured and directed to approved BMPs.
Calculations for this new facility are included in this package.
SITE DESCRIPTION
The project area is approximately 3.59 acres of disturbed area located within Briar Chapel West
development area, of which 2.24 acres have already been permitted. This extension will begin
at the current intersection of Boulder Point Drive and Briar Chapel Parkway and extend Boulder
Point Drive by approximately 1,250 feet.
The site generally slopes away from 3 high areas; 1 located at the intersection of Briar Chapel
Parkway and current Boulder Point Drive, where the site drains towards the west; 1 located
about midway of the alignment, where the site drains in both directions; and another located at
the western end of the extension which drains towards the east. Additionally, the western side of
the project area has buffered streams that are tributary to Pokeberry Creek (WS -IV; NSW).
SOILS
According to the Chatham County Generalized Soil Survey, the soils located on the site are
classified as Wedowee sandy loam, 2 to 35 percent slopes (WeB, WeC, and WeE).
The following soil descriptions are associated with the soils found on the site:
We(X) - 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.

BIORETENTION DESIGN
The goal of this bioretention area will be to remove 85% of the total suspended solids entering
from the surrounding impervious drainage area before discharging into the adjacent stream. To
obtain the goal of keeping the footprint as small as possible the temporary ponding depth for
the design is 12 ", which is the maximum desired as stated in the BMP Manual. Any runoff
exceeding the ponding depth will be discharged, via a riser structure and outlet pipe, directly
into the adjacent stream buffer at non - erosive velocities. Engineered bioretention media will not
be placed until the northern future development has been stabilized such that no damage to
the media can occur. Runoff exceeding ponding depth will still be discharged.
Design parameters were taken from the BMP manual and from DWQ's design supplement forms.
MAINTENANCE CONSIDERATIONS
The property owner shall be responsible for periodic inspection and maintenance of all
permanent stormwater management devices and shall adhere to conditions agreed upon by
the executed Operation and Maintenance agreements. Any measure that fails to function as
intended shall be repaired immediately.

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SEAL SEAL+ 4 4
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1730 Varsity Drive, Suite 500
Raleigh, North Carolina 27606
Phone: [phone], Fax: [phone]
2 REVISED PER COMMENTS RECEIVED FROM DWR 2015.07.08 F -1222
1 ISSUED FOR PERMITTING 2015.04.17
REV.NO. DESCRIPTIONS DATE
REVISIONS of \ www.mckimcreed.com e `
BRIAR
CHAPEL
by
Newland COMMUNITIES
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\ 4 BRIAR CHAPEL ` 4DATE: APRIL 17, 2015 ` 4 SCALE k 0 M &C FILE NUMBER
IVICE MAP
BOULDER POINT DRIVE EXTENSION DRAWN OJ. # 02735 –BSS
HORIZONTAL: DRAWING NUMBER
CHATHAM COUNTY, NORTH CAROLINA DESIGNED BSS 1" = 50'
CHECKED GCA VERTICAL: MAP
i 1%
BMP #20 DRAINAGE AREA MAP
PROJ. MGR. CHS N/A
i i
STATUS: FINAL DRAWINGS
FOR REVIEW PURPOSES ONLY
Of
REVISION
2