20071995 Ver 1_More Info Received_20081218

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STV/Ralph Whitehead Associates
1000 West Morehead Street, Suite 200
Charlotte, North Carolina 28208
[phone] fax: [phone]
December 18, 2008
Via FEDERAL EXPRESS
North Carolina Division of Water Quality
Winston-Salem Regional Office
585 Waughtown Street
Winston-Salem, NC 27107
QR@Rgwlgl
DEC 18 2008
DW - WAWA pU 1TY
WOODS AND STORMOM BRANCH
Attention: Ms. Sue Homewood
Subject: Response to Request for Additional Information
Hartley Drive Widening and Extension
City of High Point, Guilford County, NC
DWQ #07-1995
USACE Action I.D. #2006-20795
RWA Project No. 3202000
Dear Ms. Homewood:
On behalf of the City of High Point, STV/Ralph Whitehead Associates, Inc. (STV/RWA) is
submitting this letter of intent to submit the additional information that was requested by the
Division of Water Quality (DWQ) in a letter addressed to Mr. Keith Pugh of the City of High
Point dated November 19`h, 2008. This most recently requested information is now anticipated to
be prepared by the middle of January, 2009. Therefore, we request that the DWQ keep this
project file open in anticipation of these permit materials. The City of High Point has proposed
extending and widening the existing Hartley Drive from US 311 (North Main Street)
approximately 6,000 feet to the west, to the intersection of Westover Drive and Shadow Valley
Road. The City of High Point has contracted STV/RWA to be the acting agent and perform
wetland-permitting services for this project that is called "Hartley Drive Widening and
Extension". As you are aware, a meeting was held at the DWQ Winton-Salem office on
December 9, 2008 to discuss this Request for Additional Information, and outline a strategy for
complying with the DWQ stormwater regulations.
The following information will be submitted to the DWQ as soon as it has been prepared:
1. As stated in the DWQ Stormwater BMP Manual for dry extended detention basins (page
17-2) "Seasonally high groundwater table must be at least 2 feet below the bottom of the
basin ". The Dry Extended Basin Supplement Sheet also notes that the SHWT elevation
must be known in order to complete this checklist. Please provide this information for all
three detention basins
an employee-owned company providing quality service since 1912

Ms. Sue Homewood
December 18, 2008
Page 2
2. As stated in the DWQ Stormwater BMP Manual for dry extended detention basins (page
17-2) "A forebay is required if the design volume to the facility is over 10 acre-inches ".
For Basin #1, the Dry Extended Basin Supplement Sheet also notes that the total runoff
volume captured by the basin indicates that a forebay is required. Please modify the
design of Basin #1 to include a Forebay.
3. As stated in the DWQ Stormwater BMP Manual for dry extended detention basins (page
17-2) "A sediment depth indicator must be provided". The Dry Extended Basin
Supplement Sheet also notes that a sediment depth indicated is required. Please include
this feature in all three basins.
4. The required Items Checklist notes that a construction sequence that shows how the dry
detention basin will be protected from sediment until the entire drainage area is
stabilized is necessary. The details provided on the plan sheet are not sufficient to ensure
protections of the basin and they do not clearly indicate the appropriate steps to be taken
to convert/restore the basin following roadway construction. Please provide a more
detailed construction sequence.
5. Please provide a plant and landscape plan for the dry extended detention basins.
6 The construction detail provided for the cross vane within the mitigation area is not
sufficient. The construction detail should clearly speck size of rock, depth of rock,
anchoring of footer rocks into the stream banks, angle of wings on the cross vane, fabric
use behind the vane to prevent piping, depth of pool excavated below the cross vane, etc.
The Division must ensure that the cross vane is designed and installed properly to
promote success of the stream relocation.
As stated previously, we intend to submit the requested materials to your office before January
19th, 2009. Please do not hesitate to contact either of the undersigned at 704-372-1885, if you
have any questions.
Sincerely,
STV/RALPH WHITEHEAD ASSOCIATES, INC.
Brandon Phillips, /H.M.M.
Sr. Environmental Specialist
Michael A. I gn c o, W.S.
Senior Scientist
cc: Keith Pugh, P.E., City of High Point
Ian McMillan, DWQ