SW3191101_Add Info_20200326

ROY COOPER
Governor
MICHAEL S. REGAN
Secretary
BRIAN WRENN
Acting Director
Steve Farmartino, PE
1927 S Tryon Street Suite 310
Charlotte, NC 28203
NORTH CAROLINA
Environmental Quality
March 26, 2020
Subject: Request for Additional Information
Stormwater Permit No. SW3191101
Cambridge Village Multifamily
Lincoln County
Dear Mr. Farmartino:
The Division of Energy, Mineral and Land Resources (DEMLR), received a Stormwater
Management Permit Application for the subject project on February 19, 2020. 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, the main pool volume of wet pond 2 is too small. The SAIDA value from
the table should be interpolated based on the actual percent impervious cover of the
drainage area (35%) and the actual average depth of the wet pond (4.3 ft). Interpolating
from the SAIDA table yields a SAIDA ratio of approximately 1.04%. This results in a
minimum required surface area of 6,867 sf whereas 6,548 sf is provided. Please revise.
2. It appears that the "north half' of the project (proposed DAs 1 & 3) eventually drains to
Mountain Island Lake (WS-IV, CA) and the "south half' of the project drains to Forney
Creek (C). It appears to have been switched on the Application (Section IV, 10). Please
check with Lincoln County to ensure that all local Water Supply Watershed rules have
been adhered to since Water Supply Watershed rules are enforced at the local level, not
the State level.
3. Based on the provided BUA table in the email dated March 24, 2020, please correct the
following issues:
a. Please ensure that the BUA table information is included in the main set of plans.
b. Section IV, 10 (Deviations from Application provided with February 18th
Submission)
i. Drainage Area 1
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
NoarHcnaouNa �
Department menvinmammalQuaifty /� 919.707.9200

1. Proposed Impervious Area & Impervious Surface Area Total —
This value should be the Total BUA for proposed drainage area 1.
2. On -site Parking — This value should be the On -site Parking for
proposed drainage area 1.
3. On -site Sidewalks — This value should be the On -site Sidewalks
for proposed drainage area 1.
ii. Drainage Area 2
1. On -site Drainage Area — This value should be the sum of the On -
site BUA and On -site Pervious for proposed drainage area 2.
2. Off -site Drainage Area — This value should be the sum of the Off -
site BUA and Off -site Pervious for proposed drainage area 2.
3. Proposed Impervious Area & Impervious Surface Area Total —
This value should be the Total BUA for proposed drainage area 2.
4. On -site Parking — This value should be the On -site Parking for
proposed drainage area 2.
5. Off -site — This value should be the Off -site BUA for proposed
drainage area 2.
6. Existing BUA*** - This value should be zero (so the numbers add
up properly).
c. Supplement-EZ Form (Deviations from Supplement-EZ Form provided with
February 18th Submission)
i. Drainage Area Page:
1. Entire Site Column:
a. Line 5 — This item should be the Total BUA for the
Proposed Project Area.
b. Line 7 — This item should be the difference between the
Total BUA for the Proposed Project Area and the Total
BUA for the Existing Project Area.
c. Line 10 — These items should be the difference between the
applicable On -site BUA for the Proposed Project Area and
the applicable On -site BUA for the Existing Project Area.
d. Line 13 — This item should be On -site BUA for the
Existing Project Area.
e. Line 16 — This value should be Line 5 divided by the Total
Existing Project Area, expressed as a percent. This value
should correspond to the value shown in Section IV, 8 of
the Application.
2. Drainage Area Columns:
a. Line 5 — This item should be the Total BUA for the
Proposed Drainage Areas.
b. Line 7 — This item should be the difference between the
Total BUA for the Proposed Drainage Area (Prop DA 1 &
Prop DA2) and the Total BUA for the Existing Drainage
Area (Ex DA 1 & Ex DA 2).

c. Line 8, DA 2 — This item should be the sum of the Off -site
BUA and Off -site Permeable areas for Proposed Drainage
Area 2.
d. Line 9, DA 2 — This item should be the Off -site BUA for
Proposed Drainage Area 2.
e. Line 10 — These items should be the difference between the
applicable On -site BUA for the Proposed Drainage Area
and the applicable On -site BUA for the Existing Drainage
Area.
f. Line 13 — This item should be the On -site BUA for the
Existing Drainage Area.
4. Please correct the following issues with the Supplement-EZ Form:
a. Cover Page:
i. Line 7 — Please refer to the applicable rules to determine the minimum
width of vegetated setback (from surface waters).
ii. Line 9 — If BUA other than the approved types (Per 15A NCAC
02H . 1003 (4)(c-d)) is located within the vegetated setback, this item
should be "Yes" otherwise it should be "No".
b. Drainage Areas Page:
i. Entire Site Column:
1. Line 17 — Not required.
c. Wet Pond Page:
i. Line 25, Wet Pond 2 — This value (777.25 ft) does not match the plans and
the calculations (778.2 ft).
ii. Line 34 — Clean out depth is the distance from the permanent pool
elevation to the top of the sediment storage elevation in the forebay. For
wet pond 1, this value should be 42 inches (787.5 ft — 784.0 ft = 3.5 ft =
42 in) and for wet pond 2, this value should be 54 inches (776.5 ft — 772 ft
= 4.5 ft = 54 in).
iii. Line 44, Wet Pond 2 — The forebay exit depth is the distance from the
permanent pool elevation to the forebay exit elevation. This value should
be 60 inches (776.5 ft — 771.5 ft = 5 ft = 60 in).
iv. Line 48 — Per the provided detail (Drawdown Assembly) on sheets C-911
& C-912, the orifice is located more than 12 inches below the water
surface elevation in the cap on the downward pointing portion of the T
joint. It will draw down from below the permanent pool. These items
should be "Yes".
5. 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, 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.
6. NOTE: Per Division policy, the next review of this application will be the final review.
Failure to provide a complete submittal package will result in the project being returned
as incomplete. The return of a project will necessitate resubmittal of all required items,
including the application fee.
7. 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 24, 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 SW3191101 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: Mooresville Regional Office