SW3200202_Add Info_20200326

ROY COOPER
Governor
MICHAEL S. REGAN
Secretary
BRIAN WRENN
Acting Director
Stuart Woodard, PE
3430 Toringdon Way, Suite 110
Charlotte, NC 28277
NORTH CAROLINA
Environmental Quality
March 27, 2020
Subject: Request for Additional Information
Stormwater Permit No. SW3200202
Heritage Subdivision
Union County
Dear Mr. Woodard:
The Division of Energy, Mineral and Land Resources (DEMLR), received a Stormwater
Management Permit Application for the subject project on February 14, 2020. A review of that
information has determined that the application is not complete. The following information is
needed to continue the stormwater review:
There is a mismatch between the project name used on the Application, "Heritage
Subdivision", and the name shown on the plans, "Heritage Subdivision Phases 11 — 14"
(Section I, 1). Please revise for consistency.
2. Please clarify the extent of existing post -construction stormwater permit SW3170502 and
its relationship to this project. This project may be more accurately classified as a Major
Modification to the SW3170502 permit.
3. Please ensure that all surface waters are accounted for. Surface waters refer to "blue line"
streams as shown on USGS topographic maps (Section IV, 6). Please refer to 15A NCAC
02H .1017(10).
4. Please fill out the "Total Project Area" on the Application (Section IV, 7).
5. Please correct the following issues with the table of Section IV, 10:
a. Verify that the receiving stream name, class, and index number are correct.
Information about the receiving streams can be found at the following link:
hgps:Hncdenr.maps.arcgis.com/gpps/webappviewer/index.html?id=6e l25ad7628f
494694e259c80dd64265
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 CAROUNA -
OaparOneMofEnWromnaMal0ua6ry\ r 919.707.9200

b. The "Total Drainage Area" for drainage area 1 should reflect the total drainage
area to the proposed SCM. The value in the table does not correspond to the
calculations. Please revise for consistency.
c. The "On -site Drainage Area" for drainage area 1 should reflect the on -site (within
the project area) drainage area to the proposed SCM. The value in the table does
not correspond to the calculations. Please revise for consistency.
d. The "Proposed Impervious Area" for drainage area 1 should reflect the total
amount of BUA that will drain to the proposed SCM. The value in the table does
not correspond to the calculations. Please revise for consistency.
e. Recalculate the "% Impervious Area" taking the above comments into
consideration.
6. Please complete the entire Supplement EZ form. For this project, the form should contain
3 pages, Cover Page, Drainage Areas Page, and Wet Pond Page. The Supplement EZ
form can be found here: https://deq.nc.gov/about/divisions/energy-mineral-land-
resources/energy-mineral-land-permit-guidance/stormwater-bmp-manual (Section V &
Section VI, 3).
7. Please ensure that both an original and a copy of the Application are included in the next
submittal (Section VI, 1). Only the original Application was provided in the initial
submittal. NOTE: The signature pages do not need to be resigned unless there are noted
issues with them.
8. Please provide an original and 1 copy of the original deed restriction document limiting
the amount of BUA per lot (Section VI, 2 & Section VII). Sample deed restriction
language can be found at the following link: https://deq.nc.gov/about/divisions/energy-
mineral-and-land-resources/stormwater/stormwater-program/post-construction
9. Please fold the plan set (Section VI, 8). If the plan set is too thick to be easily folded,
consider removing irrelevant plan sheets, such as utility, lighting, roadway profiles, etc...
If it is not needed for the review of the State post -construction stormwater approval, it
does not need to be included. Please refer to the Application and 15A NCAC
02H .1042(2) for guidance.
10. Please show and identify the surface waters (including acreage) on the plans (Section VI,
8h) as well as the associated required buffers (Section VI, 8p).
11. Please dimension all proposed BUA on the plans (Section VI, 8j). The information
provided in the Application/Supplement-EZ should be verifiable on the plans.
12. Please delineate the wetlands on the plans or provide a note stating that no wetlands exist.
Provide documentation of the qualifications and identity of the individual who made this
determination (Section VI, 8m).
13. While it is noted that the stormwater report contains a drainage area map for proposed
conditions, per Section VI, 8o, the drainage area to the SCM must be included in the
main set of plans.

14. Please provided documentation showing that Mr. Johnson has signatory authority for The
Kolter Group, LLC (Section VI, 11).
15. Please show the pond in profile view on the plans. This view should include the sediment
storage elevation and excavated bottom elevation for both the forebay and main pool.
Please also ensure that the forebay entrance is deeper than the forebay exit.
16. Sheet C9.01 shows the WQv elevation as 597.6 ft whereas the calculations indicate that
this elevation is 598.1 ft. Please revise for consistency.
17. The Grace Point Drive outfall into the proposed wet pond appears to short-circuit the
pond. Currently, short-circuiting is kind of subjective (We're working on a more rigorous
and less subjective definition). What I use to determine if a pond is short-circuiting is to
take the total surface area at the permanent pool elevation and divide this by the shortest
flow path from the inlet to the outlet squared ( Flow SAPathPP 2)• This quantity should be less
than or equal to 1.0. The inlet in question currently has a direct flow path of about 230' .
Using the above mentioned methodology results in an area over flow path squared of
about 1.12 so this would be a short-circuit. A pond this size would need about 250-ish
feet of flow path to not short-circuit (More would be better, but 250-ish feet would be
acceptable). You are also welcome to provide some other calculation methodology to
show that the pond is not short-circuiting.
18. As designed, the project does not meet the definition of "Runoff Treatment". Per 15A
NCAC 02H .1002(43), "the volume of stormwater runoff generated from all of the built -
upon area of a project at build -out during a storm of the required storm depth is treated in
one or more primary SCMs...". There are sections of the proposed BUA that do not drain
to nor are treated by the proposed SCM.
19. 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://edocs.deq.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 27, 2020, 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 SW3200202 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: Mooresville Regional Office