SW5210603_Add Info_20210923

ROY COOPER
Governor
ELIZABETH S. BISER
Secretary
BRIAN WRENN
Director
Kevin Varnell, PE
PO BOX 1108
Nashville, NC 27856
NORTH CAROLINA
Environmental Quality
September 23, 2021
Subject: Second Request for Additional Information
Stormwater Permit No. SW5210603
Duck Thru at Spring Hope, NC
Nash County
Dear Mr. Varnell:
The Division of Energy, Mineral and Land Resources (DEMLR), received a Stormwater
Management Permit Application for the subject project on August 19, 2021. A review of that
information has determined that the application is not complete. The following information is
needed to continue the stormwater review:
Prior Comment 1— Based on the provided information, it appears as though the
Bojangles at Spring Hope (SW5200701) will need to perform a minor modification on
their permit, indicating that the drainage area and BUA draining to their SCM are being
reduced (we can add language into their modified permit so that they get the credit for
this reduction in BUA) and that part of their project area is being sold off. This minor
modification should be applied for concurrently with this permit (ideally, I would like to
issue them together since they are intertwined). Since BUA that will exist within this
(SW5210603) project area will be treated by the Bojangles (SW5200701) SCM, the
Bojangles permit (SW5200701) will be set up as the master permit and this project
(SW5210603) will utilize an off -site SCM. For this project (SW5210603), you will need
to do the following:
a. Section II, 2 of the Application — Please indicate that this project also drains to an
offsite stormwater system (do not uncheck the high -density box).
b. Section IV, 9 of the Application — Please update this value to "2", one for the
proposed, on -site wet pond and one for the off -site SCM.
c. Section IV, 10 of the Application — Please add a second drainage area column for
the portion of the project area that drains to the off -site SCM. For this drainage
area to the off -site SCM, only include the portion of the drainage area that is
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 _
oepm nt of EnvimnmwUl uwl ry 919.707.9200

located within this project's project area, not the entire drainage area to the off -
site SCM. Any proposed BUA added to the access road (outside of this project
area, but within the project area of SW5200701) can be handled by the
SW5200701 minor modification.
d. Similar to the prior point, the Supplement-EZ form should be revised to include
the use of the off -site SCM. In addition to including the off -site drainage area on
the Drainage Area Page of this form, there is an item on the Cover Page (Line 6)
that should be marked as "Yes" and doing so will allow an Off -Site SCM Page to
be generated (similar to the Wet Pond Page).
2. Prior Comments 2 & 3 — Laserfiche is currently down so I can't verify that these
comments have been addressed (I have no reason to doubt that they were addressed, but I
just can't verify at this time). Once Laserfiche is back online, I will verify that these items
have been addressed and let you know if they have not been. If you plan on resubmitting
the electronic files within the next couple of business days, please email me the PDFs
since you will not be able to upload them through the usual portal.
3. Prior Comment 5 — "Per 1 SA NCAC 02H .1003(3)(b), any off -site areas that drain to
the proposed SCM must be accounted for at their full build -out potential. This can either
be handled by having the Applicant and the Off -site Property Owner enter into a legal
agreement limiting the amount of BUA that can be built on this off -site area (there's
more information on this following the comments) or by assuming that the off -site area is
at its maximum build -out potential (typically 100% BUA). For this reason, it is
recommended to bypass all off -site areas around the proposed SCM. " The off -site
drainage area must either be bypassed or accounted for at its full build -out potential,
either through a legal agreement limiting future BUA placement in this area (which
NCDOT will most likely not enter into with the Applicant) or by assuming this area is at
its full build -out potential (100% BUA). While not likely, it is possible that, at some point
in the future, NCDOT could add a sidewalk, a bike path, or re -grade this area to increase
the amount of BUA being directed to the proposed SCM without the owner's consent
(and by extension bring the SCM out of compliance with the permit). It is for this reason
that we require any off -site drainage areas that are not bypassed or limited by a legal
agreement to be accounted for at their full build -out potential. Taking a quick look at the
calculations, the proposed wet pond appears to be able to accommodate this extra storage
volume without the need for a redesign. You can place a note in the "Additional
Information" section of the Wet Pond Page of the Supplement-EZ Form indicating that
this wet pond is oversized and has "x" cubic feet of additional water quality storage
volume available to account for this off -site drainage area.
4. Prior Comment 9 — "Since there are off -site components to the proposed SCM drainage
area, please explain how the off -site impervious area was determined (Section IV, 11). "
Similar to above, you can add a note here stating that the wet pond has additional water
quality storage volume and can treat this off -site area if it ever becomes BUA.
5. Prior Comment 13 — "...Please also clearly show the sediment storage elevation (in
both the forebay and main pool) on the wet pond cross-section. " Please do this as it is

currently ambiguous as to how deep the wet pond should be excavated (the plan view
indicates one thing and the cross-section another). Please provide some clarification on
the cross-section view that indicates that the forebay and main pool need to be excavated
to 255 ft and 251 ft respectively. This could be accomplished with a note under the detail
or by making the detail more detailed.
6. Prior Comment 17 —"The incremental storage shown at elevation 262.0 on plan sheet
CE-04 (10,015 cf) appears to be incorrect (the incremental storage shown might be the
provided storage between elevation 261.0 & 262.0 however, a cross-section for elevation
261.47 is included in the stage -storage table and should be accounted for). " There
appears to be an issue with the stage -storage table near the permanent pool elevation. The
cross -sectional area of pool at the temporary ponding elevation (261.4 ft) does not appear
to be correct. The cross -sectional area at elevation 261.4 ft (11,566 sf) is larger than the
cross -sectional area at elevation 262.0 ft (11,333 sf), which isn't possible, the cross -
sectional areas of the pond should increase as the elevation increases (otherwise the pond
would have an hourglass figure). Interpolating the cross -sectional area at elevation 261.4
ft from the cross -sections above and below it results in a cross -sectional area at elevation
261.4 ft closer to 10,000 sf (and a cumulative storage volume at this elevation of a couple
hundred cubic feet less than the design volume). Please revise as needed.
7. Drainage area le (plan sheet CE-08) appears to have more BUA (9,939.7 sf) than
drainage area (9,929.7 sf). Please revise as needed.
8. Please provide calculations and outlet protection (if applicable) for the 4 ft wide concrete
flume that flows into the forebay of the proposed wet pond (General MDC 4).
9. 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 USPS:
Suzanne McCoy
1612 Mail Service Center
Raleigh, NC 27699-1612
While it is not required, it is recommended that the off -site drainage from upstream properties
be diverted around the SCM since the Applicant cannot maintain control over the development
of property that they do not own. If the Applicant elects to account for off -site drainage, the off -
site area must be accounted for at its full build out potential (typically 100% BUA) or there must

be a recorded legal agreement in place between the Applicant and the Owner of the upstream
property in which the Owner of the upstream property agrees to record a deed restriction limiting
the minimum/maximum amount of BUA on the upstream property that will be treated in the
Applicant's SCM, the locations and sizes of access and drainage easements, how construction
and/or ongoing maintenance costs will be handled, maintenance responsibility, a list of legal
recourses available to each party should one party fail to hold up their end of the agreement, and
any other related legal issues.
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 October 23, 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 SW5210603 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,
Jim Farkas
Environmental Engineer
Stormwater Program
cc: Raleigh Regional Office