SW1180501_Add Info Request_20180614

Energy, Mineral
and Land Resources
ENVIRONMENTAL QUALITY
June 14, 2018
Mr. Scott Burwell, PE
Ms. Christine Brown, CPSWQ, CPESC
McGill Associates
55 Broad Street
Asheville, NC 28801
Subject: Request for Additional Information
Stormwater Permit No. SW1180501
West Buncombe Fire Department — Asheville, NC
Buncombe County
Dear Mr. Burwell and Ms. Brown:
ROY COOPER
Governor
MICHAEL S. REGAN
Secretary
WILLIAM E. TOBY VINSON, JR.
Interim Director
The Division of Energy, Mineral and Land Resources (DEMLR), received a Stormwater
Management Permit Application for the subject project on May 18, 2018. A review of that
information has determined that the application is not complete. The following information is
needed to continue the stormwater review:
1. All new built upon area must be treated in a primary SCM before being discharged. As
designed, approximately one third of the proposed BUA will be discharged without
treatment. Please provide treatment for the BUA draining to Cl 1 and Cl 3.
2. Was a geotechnical investigation performed to determine the depth to the seasonal high
water table and the hydraulic conductivity of the subsoil? If so, please submit a copy of
the geotechnical report.
3. The SCM details on Sheet 503 indicate that the media depth is 20". The minimum media
depth for a bioretention system without trees and shrubs is 24" if no internal water
storage is provided and 30" if internal water storage is provided. Note that the
Supplement EZ form indicates the depth of the media as 24".
4. The specified media mix on Sheet 503 does not match the mix required by Bioretention
MDC 6. In addition, please specify coarse washed sand.
5. Please add specifications to the plans that the P -index of the media must be less than 50
and that the media shall not be mechanically compacted (Bioretention MDC 7 and 8,
respectively).

6. The Supplement EZ form states that there will be a drawdown orifice to drain the system
for maintenance. Please show the location and size of this orifice on the details.
7. Please specify on Sheet 503 that the No. 57 stone used to house the underdrain must be
washed.
8. Please note on the plans that the 10 -foot wide embankment around the bioretention
system serves as a maintenance access.
9. What is the design ponding depth of the system? The details on Sheet 503 are conflicting
(12" vs. 18").
10. Provide pdfs of all revisions, 2 hardcopies of revised plan sheets, and 1 hardcopy of other
documents. Pdfs must be uploaded using the form at:
hqps:Hedocs.deg.nc.gov/Forins/SW ProjectSubmittal
Please note that this request for additional information is in response to a preliminary review.
The requested information should be received by this Office prior to July 14, 2018, or the
application will be returned as incomplete. The return of a project will necessitate resubmittal
of all required items, including the application fee. Please reference the State assigned project
number SW1180501 on all correspondence.
If you need additional time to submit the information, please submit your request for a time
extension to the Division at the contact below. The request must indicate the date by which you
expect to submit the required information. The Division is allowed 90 days from the receipt of
a completed application to issue the permit.
The construction of any impervious surfaces, other than a construction entrance under an
approved Sedimentation Erosion Control Plan, is a violation of NCGS 143-215.1 and is subject
to enforcement action pursuant to NCGS 143-215.6A.
If you have any questions concerning this matter please feel free to contact me at
Corey.Anen(cncdenr.gov or [phone].
Sincerely,
�& % 64'—
Corey Anen
Environmental Engineer
Stormwater Program
cc: Asheville Regional Office
Randy Ratcliff – West Buncombe Fire Department
Nothing Compares.
State of North Carolina I Environmental Quality I Energy, Mineral and Land Resources
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