SW6210601_Add Info_20210712

ROY COOPER
Governor
JOHN NICHOLSON
interim Secretary
BRIAN WRENN
Director
C. Scott Brown, PE
409 Chicago Drive, Suite 112
Fayetteville, NC 28306
NORTH CAROLINA
Environmental Quality
July 12, 2021
Subject: Request for Additional Information
Stormwater Permit No. SW6210601
Graceland Subdivision
Hoke County
Dear Mr. Brown:
The Division of Energy, Mineral and Land Resources (DEMLR), received a Stormwater
Management Permit Application for the subject project on June 2, 2021. A review of that
information has determined that the application is not complete. The following information is
needed to continue the stormwater review:
As designed, this project does not meet the requirements needed to be considered a low -
density project (Section II, 2 & Section IV, 1). A low -density project is not allowed to
collect stormwater runoff in a piping network (Piping is only allowable in certain
unavoidable situations such as transporting stormwater runoff underneath a driveway). It
is noted that Hoke County requires the use of curb and gutter on all projects, but that is
not sufficient reason to include a pipe network in a low -density project. Curb cuts (as
shown in Figure 2 in Part E-1 of the Stormwater Design Manual) should be used where
possible to transfer stormwater runoff from the curb & gutter to vegetated conveyances
thus avoiding the use of pipes. If it is not possible to use curb cuts, inlets can be used
provided they immediately discharge to a vegetated conveyance. If stormwater needs to
be transported along a roadway, it should be done via vegetated conveyance, not in a
pipe. Please either remove avoidable piping or redesign this project as a high -density
project.
2. Per the provided USGS topographic map, there appears to be on -site surface waters
(separating the northern portion of the project from the southern portion of the project).
Please ensure that these surface waters are accounted for in Section IV, 6 of the
Application, are clearly identified on the plans (Section VI, 8h), and have the associated
vegetated setback shown on the plans (Section VI, 8p). Please revise Section IV, 7-8 of
the Application and any other applicable submission items (such as per lot BUA
allocation) that may be affected by this.
D E Q�� 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 _
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3. The sum of the Impervious Surface Areas listed in the table under Section IV, 10 do not
add up to the Total (379,760 sf + 175,613 sf + 27,462 sf :� 582,905 sf). Please revise.
4. The provided low -density supplement form is an old, outdated form (Section V & Section
VI, 3). It is recommended to use the latest version of the Supplement-EZ Form, which
can be found at the following link: https://deq.nc.gov/about/divisions/energy-mineral-
and-land-resources/stormwater/stormwater-program/stormwater-design This form
includes the ability to handle low -density developments.
5. Time of concentration calculations were only provided for Ditches 1-3. Please ensure that
these calculations are provided for all proposed vegetated conveyances (Section VI, 7).
Please also provide the rainfall intensity ("i") values used to calculate the 10-year design
flow through the vegetated conveyances.
6. Please provide a note in the main set of plans indicating the individual that made the on -
site wetland delineation (Section VI, 8m).
7. Please delineate the drainage areas to the proposed vegetated conveyances in the main set
of plans (Section VI, 8o).
8. Please include the allowable velocity (Vallow) for all of the proposed vegetated
conveyances in the supplement. Maximum allowable velocities are based on the
vegetative cover and soil type for each conveyance. A table listing these velocities is
provide in Part C-I I of the Stormwater Design Manual
(https://files.nc. gov/ncdeq/Energy%20Mineral%20and%20Land%20Resources/Stormwat
erBMP%20Manual/C- I I --Treatment-Swale-11-20-2020.pdf).
9. While not required, it is recommended to either better define the downstream portion of
Ditch 6 or reconfigure it so that the velocity in it is less than 2.0 fps. Ditch 6 does not
appear to directly discharge to a wetland, but it is fairly close to doing so (the off -site
contour lines are not provided so it is not possible to determine if the flow does or does
not enter the wetland).
10. Provide pdfs of all revisions, 2 hardcopies of revised plan sheets, 1 hardcopy of other
documents, and a response to comments letter briefly describing how the comments have
been addressed.
a. Pdfs must be uploaded using the form at:
https:,[/edocs.deq.nc.gov/Forms/SW-Supplemental-Upload
b. Hard copies must be mailed or delivered to the following address:
i. For FedEx/UPS:
Suzanne McCoy
512 N. Salisbury Street, Office 640K
Raleigh, NC 27604

ii. For LISPS:
Suzanne McCoy
1612 Mail Service Center
Raleigh, NC 27699-1612
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 August 11, 2021, 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 SW6210601 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
[e-mail] or [phone].
Sincerely,
V "I
Jim Farkas
Environmental Engineer
Stormwater Program
cc: Fayetteville Regional Office