20060963 Ver 3_More Info Received_20080908

WITHERS
September 5, 2008
DWQ 401 Unit
2321 Crabtree Blvd.
Suite 250
Raleigh, NC 27604
Attn: Annette Lucas
RAVEN EL
ENGINEERS I PLANNERS
D6 W? Vs
Re: Renaissance Park Commercial
W&R Project No. 02050170.10
Dear Ms. Lucas:
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This letter follows our meeting on September 4, 2008 at your offices. The purpose of this
letter is to summarize the discussion that took lace regarding buffer and stormwater
permitting for the above referenced project.
The Renaissance Park Development includes 8 stormwater BMPs which have been
permitted and constructed. A ninth BMP was planned as part of the commercial portion of
the development, generally located at the intersection of Tryon Road and Ileagnes Road in
Raleigh, NC.
The original plan included one stormwater BMP located on the north side of Tryon Road.
The outfall from the BMP would utilize an existing cross pipe under Tryon Road, which
discharges into a buffered feature south of Tryon Road. Stormwater runoff from the new site,
as well as runoff from portions of an existing site was to be directed into the stormwater
BMP, which would be sized for the entire watershed.
The purpose of the meeting was to identify potential implications of a revised stormwater
management plan. In short, the revised plan handled stormwater by directing only the flow
from the existing impervious areas to the existing cross pipe. The proposed stormwater BMP
will be moved to an undeveloped parcel south of Tryon Road, and stormwater from new
impervious surfaces will be directed to the BMP via a new cross pipe. A new outfall is to be
created from the BMP into the buffered feature.
ill MacKenan Drive i Cary, NC 27511 1 tel: [phone] fax: [phone] i www.withersravenel.com
7040 Wrightsville Avenue i Suite 101 i Wilmington, NC 28403 1 tel: [phone] fax: [phone]
Brunswick Surveying 1 1027 Sabbath Home Rd, SW i Supply, NC 28462 1 tel: [phone] fax: [phone]

Ms. Lucas
9/5/2008
Page 2 of 2
It is anticipated that the new BMP will be a constructed wetland, sized for the contributing
drainage area. Per current stormwater and buffer regulations, the outfall from the
constructed may result in additional buffer impacts, which would require written approval
from the Division of Water Quality. Similar impacts have been permitted in the past
provided that the stormwater management structures are designed in accordance with the
latest guidance.
At this time, the Division of Water Quality expressed no immediate concerns over the
revisions to the previously approved plan. Full construction drawings and stormwater
management plans will need to be reviewed and approved by the City of Raleigh
stormwater staff prior to approval of any additional buffer disturbances. Upon approval from
the City, the applicant will forward a courtesy set of plan to the Division for their files.
Assuming that no runoff from new impervious surfaces is directed to the existing stormwater
outfall, that outfall may be extended as required for the associated roadway widening
project on Tryon Road. No permit would be required for this activity.
The meeting was requested primarily for discussion of the Renaissance Park Commercial
site. The majority of watershed area which can be directed to the new stormwater BMP
location is within the project limits of the previously approved site. At this time, we do not
anticipate and additional wetland or surface water impacts due to the proposed revision.
There may be additional development which can be supported by this stormwater feature,
and any such development would require additional approvals from the City of Raleigh
prior to construction.
If you have any questions or comments regarding the contents of this letter, please do not
hesitate to contact me at the number below.
Sincerely,
WITHERS -RAV NEL, INC.
Hunter C. Freeman, P.E.
06-0963v2 Rnaissance Park Commercial
Subject: 06-0963v2 Rnaissance Park Commercial
From: Annette Lucas <[e-mail]>
Date: Wed, 10 Sep 2008 11:24:32 -0400
To: Hunter Freeman <[e-mail]>
CC: Annette Lucas <[e-mail]>
Dear Hunter:
I have received your letter dated September 5, 2008 about the stormwater management
plan for this project. I concur that it is acceptable to locate the remaining BMP
needed for this site on an undeveloped parcel south of Tryon Road as long as it is
properly sized for the entire drainage area and designed in accordance with the most
recent version of the BMP Manual. I also concur that it is acceptable to bypass
stormwater from the adjacent development site directly to the receiving stream.
Sincerely,
Annette Lucas
1 of 1 9/10/2008 11:24 AM