SW3230701_Response To Comments_20240223

j!j THOMAS & HUTTON
1020 EUCLID AVENUE
CHARLOTTE, NC 28203 I 980.201.5505
WWW.T H O MASAN D H UTTO N.CO M
February 22, 2024
NCDEQ- Land Quality
Attn: Jim Farkas
512 N. Salisbury Street, Office 640M
Raleigh, NC 27604
Re: Stewart's Grove
#SW3230701
Wingate, NC
J-31540.0000
To whom it may concern:
This letter serves as acknowledgement that we have revised the previously submitted package to
address all comments below as follows:
Stormwater-Jim Farkas
1. As designed, the project does not appear to capture and treat sufficient on-site BUA in
order for the project to meet Runoff Treatment(15A NCAC 02H .1002(43)). Per the
application, the%BUA for the site is shown as 34.76%which would result in approximately
6.33 ac of new BUA whereas the SCM is only capturing &treating approximately 5.14 ac.
Please ensure that the net increase in on-site BUA is being captured and treated in one or
more primary SCMs. If it is not practicable to capture and treat all of the new BUA, the
uncaptured areas of the project can be permitted as a low- density area (provided that
they meet all of the low-density requirements outlined in 15A NCAC 02H .1003(2)). Please
revise as needed.
The sand filters and dry ponds have been sized to capture the entire new development,
with the 75%water quality factor for sand filter dry ponds.
2. Per the Supplement-EZ Form, the total amount of BUA allocated to the subdivided lots for
the entire site (Entire Site Column, Line 9) is 153,370 sf whereas the total amount of BUA
allocated to the subdivided lots per the deed restriction document is 153,390 sf. Please
revise as needed.
Revised.

3. Please ensure that the off-site portions of the drainage areas to the SCM is correctly
accounted for at its full build-out potential (per 15A NCAC 02H .1003(3)(b)). Full build- out
potential is determined by either having the property owner and permittee enter into a
legal agreement limiting the amount of BUA and drainage area being directed from the
off-site area to the SCM or by assuming that the off-site area is 100% BUA, its full build- out
potential. It is recommended to bypass off-site drainage areas around proposed SCMs as
the permittee has no control over how off-site areas are developed (which is why they
are required to be accounted for at their full build-out potential). Off-site areas are not
required to be captured and treated, but if they are not bypassed, they must be
accounted for in the SCM design. Please revise as needed.
Assuming 100%impervious for offsite area has been applied to the model.
4. Please correct the following issues with the design of the SCM:
a. Per the elevation information for the planting zones shown on plan sheet C-2.8, the
portion of the stormwater wetland located between elevations 536.5 and 537.25 is
unaccounted for. Each portion of the stormwater wetland must fall into one of the
zones. Everything between 0 and 15 inches above the permanent pool surface is part
of the temporary inundation zone, everything between 0 and 9 inches below the
permanent pool surface is part of the shallow water zone, and everything more than 9
inches below the permanent pool surface is part of the deep pools (either forebay or
non-forebay deep pools, depending on the location). Please also include a contour
line at elevation 537.25 (bottom of the shallow water zone) on the SCM detail and a
cross- sectional area at this elevation in the provided stage-storage table. Please
revise as needed.
b. General MDC 4- Please provide sizing/design calculations for the riprap aprons
indicating that the inlet and outlet of the SCM are stable per the MDC.
c. Stormwater Wetland MDC 5-As designed,the inlet and outlet of the SCM appear too
close to each other, resulting in short-circuiting. Please either relocate the inlet
and/or outlet or add berms/baffles so that the flow path from the inlet to the outlet is
increased, better utilizing the entire SCM for treatment. If using berms/baffles to
increase the flow path, the berm/baffle must extend to above the temporary pool
surface elevation.
Prior SCM design has been replaced.
5. Please add the following items to the plan set:
a. Drainage area delineation to the SCM. It is noted that a drainage area delineation is
provided in the calculations, however, per 15A NCAC 02H .1042(2)(g)(iv),the
drainage area delineation must be included in the main set of plans. Please revise.
b. Planting plan for the SCM. It is noted that a plant list is provided in the calculations,
however, per 15A NCAC 02H .1042(2)(i), a planting plan for the SCM must be
provided in the plan set. Please refer to the cited rule for a list of items that must be
included in the planting plan.
Revised as appropriate.

6. Please correct the following with the Supplement-EZ Form:
a. Drainage Area Page:
I. The entire site column is an accounting of all of the BUA located within the project
area, whether or not it drains to the SCM and typically does not include off-site
areas. When asked for the "drainage area" of the entire site, the project area
should be used. Lines 19-21 are not required for this column.
II. Please revise the BUA accounting as needed to account for the off-site portion of
the drainage area at its full build-out potential.
b. Stormwater Wetland Page:
I. Line 20-The proposed design does not appear to have berms/baffles to increase
the flow path through the SCM.
II. Lines 24-39- Revise if needed in accordance with earlier comments.
Ill. Line 40-
IV. Lines 47 & 48-These items should only be used if the primary drawdown device is
a weir(per the design, the primary drawdown device is the 1.75 in orifice).
Revised per new SCM design.
7. While it is not required, it is strongly recommended to relocate the outlet structure so that
it is closer to the banks of the proposed stormwater wetland. Locating the outlet structure
away from the banks of the SCM makes routine maintenance difficult to perform
(maintenance that is difficult to perform is less likely to be performed).
Outlet structure for sand filter/dry pond has been placed appropriately.
8. 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:
For FedEx/UPS:
Jim Farkas
512 N. Salisbury Street, Office 640M
Raleigh, NC 27604
For USPS:
Jim Farkas
1612 Mail Service Center
Raleigh, NC 27699-1612
Hand Delivery:
Please reach out to me prior to hand delivering a submission to make sure that I (or
someone else in my group) will be able to receive the submission. Do not leave the
package in the foyer with the security guard.

NOTE: Hard copies should not be sent to a Regional Office. Doing so will delay the review
process and the submission package may be lost while being sent from the Regional
Office to me in the Central Office.
Copies have been provided as required.
9. 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, it must either be accounted for as 100% BUA (its full build out potential,
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.
New design keeps most of offsite drainage away from development, small area of offsite
drainage has been accounted for as 100% impervious.
We look forward to receiving the approved certification for the referenced project to
allow us to proceed.If you have any questions, comments,or desire additional information, please
contact our office at [phone].
Sincerely,
,/".' Aid--
THOMAS & MUTTON
Jack McFadden, PE