SW6210202_Add Info Request_20210324

ROY COOPER
Governor
DIONNE DELLI-GATTI
Secretary
BRIAN WRENN
Director
Jerry Oberholtzer, PE
Lowe Engineers
990 Hammond Drive, Suite 900
Atlanta, GA 30328
NORTH CAROLINA
Environmental Quality
March 24, 2021
Subject: Request for Additional Information
Stormwater Permit No. SW6210202
Fort Bragg Special Operations Facility Addition — PN88658
Cumberland County
Dear Mr. Oberholtzer:
The Division of Energy, Mineral and Land Resources (DEMLR), received a Stormwater
Management Permit Application for the subject project on February 10, 2021. A review of that
information has determined that the application is not complete. The following information is
needed to continue the stormwater review:
Please provide a geotechnical investigation verifying that there is sufficient separation
from the bottom of the bioretention cells to the seasonal high water table (Bioretention
MDC 1).
2. Please provide calculations for all inlets and outlets showing that the riprap is designed to
prevent erosion from the peak flow from the 10-year storm event (General MDC 4).
3. When calculating the water quality volume using the NRCS method, the runoff volumes
from impervious surfaces should be calculated separately from the runoff volumes from
pervious surfaces. Using a weighted curve number greatly underestimates the runoff from
the drainage area.
4. The weir elevations from bioretention cells 3 and 5 are set at the same elevation as the
planting surface. The outlets from all the bioretention cells must be set at an elevation
greater than the ponding volume from the water quality design volume.
5. 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:
https:Hedocs.deg.nc.gov/Forms/SW_Project Submittal
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 April 23, 2021, or the
North Carolina Department of Environmental Quality I Division of Energy, Mineral and Land Resources
512 North Salisbury Street 1 1612 Mail Service Center I Raleigh, North Carolina 27699-1612
NORTH CAROLINA
uepaa nt of enmmnmmi Q.1; 919.707.9200

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 SW6210202 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&ncdenr.gov or [phone]. Please note that due to the ongoing Covid-19
pandemic, I will be teleworking and will be most easily reached by email.
Sincerely,
Steven Corey Anen, PE
Environmental Engineer
Stormwater Program
cc: Fayetteville Regional Office
D E Q J� North Carolina Department of Environmental Quality Division of Energy, Mineral and Land Resources
512 North Salisbury Street 1 1612 Mail Service Center Raleigh, North Carolina 27699-1612
NORTH CAROLINA -
D.panm.mof Envlloamaotal Duality 919.707.9200