20070776 Ver 1_More Info Letter_20071121

~O~ W A TFRQ Michael F. Easley, Governor
`d, ~ William G. Ross Jr., Secretary
C/) rte.. North Carolina Department of Environment and Natural Resources
~ -_~
~ ,C. Coleen H. Sullins, Director
Division of Water Quality
November 21, 2007
DWQ EXP No. 07-0776v2
Haywood County
CERTIFIED MAIL: RETURN RECEIPT REQUESTED
Waynesville Commons Retail Associates, LLC
Attn: David Scarnati
1765 Merriman Road
Akron, OH 44313
Subject Property: Waynesville Commons
REQUEST FOR MORE INFORMATION (STORMWATER MANAGEMENT PLAN) -
EXPRESS REVIEW
Dear Mr. Scarnati:
On November 20, 2007, the Division of Water Quality (the "Division") received some of the additional
information requested to accompany your stormwater management plan for the above-referenced project.
The DWQ has determined that this information is still incomplete.
Please provide the additional information requested below in order to continue review of your project
and to prevent denial of your application as required by 15A NCAC 2H .0506:
Additional Information Requested
1. Runoff from Roof of Wal-Mart Building
a. No treatment has been provided for the runoff from this area as requested. Please be advised
that the DWQ will not accept direct discharge of untreated stormwater to Richland Creek.
2. Bioretention C
a. If the grassed swale drains to the bioretention cell, please revise the Bioretention Supplement
to include the drainage area of the grassed swale. The grassed Swale could serve as a
pretreatment device for the bioretention cell.
b. Please explain why the drainage districts WW and W in the original submittal have been
taken off from the total drainage area to the bioretention cell, and show how the stormwater
in these areas are being treated.
c. The soil report indicates that the average permeability of the insitu soil is 17.35in/hr (or 11.34
in/hr when the highest value is discarded). Please explain why the supplement form indicates
an insitu soil permeability value of 4.00 in/hr.
d. Soil report shall indicate the composition of insitu soil.
e. Please provide supporting calculations to show how the two drawdown times (12 hrs and 28
hrs) were obtained (the limiting infiltration rate is the lower value of the infiltration rate of
the media and the insitu soil when there is no underdrain pipe).
Nao°~EhCarolina
401 Oversight I Express Review Permitting Unit d -'atura~~l~
1650 Mail Service Center, Raleigh, North Carolina 27699-1650
2321 Crabtree Boulevard, Suite 250, Raleigh, North Carolina 27604
Phone: [phone] FAX [phone] Internet: http://h2o.enr.state_,_nc.usJncwetlands
An Equal OpportunitylAffirmativeAaion Employer - 50% Recycled110% Post Consumer Paper

Waynesville Commons Stormwater Management Plan
Page 2 of 2
November 21, 2007
3. Infiltration Trenches
a. The infiltration trenches should be designed as offline BMPs. That is, volume in excess of the
treatment volume shall bypass the device. Please show how the stormwater volume in excess
of the water quality volume (the first inch of rainfall) bypasses both devices.
b. The infiltration device, especially such as the proposed buried type, should be designed to
have a pretreatment device including but not limited to forebays (sediment traps), grassed
swales, filter strips, etc. to avoid frequent clogging.
c. Total runoff captured by the infiltration trench for 5 S is nearly three times the maximum
allowed. Please redesign the device to receive total runoff as close to 2.0 acre-inch as
practicable.
d. Insitu soil infiltration rate: please discard the highest value of infiltration rate of the insitu soil
and use the average value of the remaining data. The minimum is not representative.
e. Bottom of infiltration trench must be lined with a layer of clean sand with a depth of 4 inches
or greater or equivalent fabric (unless native soil has 1-2% fines).
f. Please explain why the impervious area for the infiltration trench for SS differs in the
supplement form (250,411 ft2) from that in the supporting Hydrocad calculations
(222,922ft2).
g. Please explain why the existing impervious area for drainage area 7S is greater than the total
drainage area in the Project Information Table for Item III.6.
Please respond within five (5) days of the date of this letter by sending two (2) copies of the above
information in writing. The Express Review Program is a process that requires all parties to participate in a
timely manner.
This letter only addresses the application review and does not authorize any impacts to wetlands, waters
or protected buffers. Please be aware that any impacts requested within your application are not
authorized (at this time) by the DWQ.
Please contact Joseph Gyamfi or Lia Myott at 919-733-1786 if you have any questions regarding or
would like to set up a meeting to discuss this matter.
Sincerely,
s /~
G~
Cyndi Karoly, Supervisor
401 Oversight/Express Review Permitting Unit
CBK/jg
cc: Loretta Beckwith, USACE Asheville Regulatory Field Office
Kevin Barnett, DWQ Asheville Regional Office
File Copy
Central Files
Charles Christy, P.E., Wade Trim, Inc., Two Town Square Blvd, Suite 245, Asheville, NC
28803