SW3211201_Add Info_20220119

ROY COOPER
Governor
ELIZABETH S. BISER
Secretary
BRIAN WRENN
Director
Chris Bridges, PE
1186 Stonecrest Boulevard
Tega Cay, SC 29708
AND
Toll Southeast LP Company, Inc.
Attn: Jaime Pou, Division President
14529 Grand Palisades Parkway
Charlotte, NC 28278
NORTH CAROLINA
Environmental Quality
January 19, 2022
Subject: Request for Additional Information
Stormwater Permit No. SW3211201
Hemby Place
Union County
Dear Mr. Bridges and Mr. Pou:
The Division of Energy, Mineral and Land Resources (DEMLR), received a Stormwater
Management Permit Application for the subject project on December 6, 2021. A review of that
information has determined that the application is not complete. The following information is
needed to continue the stormwater review:
This project is located within the Sixmile Creek watershed which is subject to the Goose
Creek Watershed Rules (15A NCAC 02B .0602). These rules stipulate that,
"Development and redevelopment shall implement stormwater management measures
that promote infiltration of flows and groundwater recharge for the purpose of
maintaining stream base flow. " Please provide an explanation of how the selected SCM
promotes infiltration of flows and groundwater recharge. If it is not practical to use an
SCM that promotes infiltration of flows and groundwater recharge for this site, please
provide an explanation for why it is not practical to do so.
2. There appears to be a discrepancy between the information show in in Section IV of the
Application and that shown in the Supplement-EZ Form. Please revise as needed for
correctness and consistency:
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

a. The percent imperviousness of the project area is shown as 16.47% (Section IV, 8
of the Application) and as 11.58% (Supplement-EZ Form, Drainage Areas Page,
Entire Site Column, Line 18).
b. The BUA allocated to the individual lots is shown as 109,900 sf (Section IV, 10,
"On -site Buildings/Lots" Line of the Application) and as 199,722 sf (Supplement-
EZ Form, Drainage Areas Page, DA 1 Column, Line 9).
c. The BUA allocated to non -subdivided roadways is shown as 104,036 sf (Section
IV, 10, "On -site Streets" Line of the Application) and as 95,618 sf (Supplement-
EZ Form, Drainage Areas Page, DA 1 Column, Line 12, Roadway).
d. The BUA allocated to non -subdivided parking is shown as 27,364 sf (Section IV,
10, "On -site Parking" Line of the Application) and as 0 sf (Supplement-EZ Form,
Drainage Areas Page, DA 1 Column, Line 12, Parking).
e. The BUA allocated to non -subdivided sidewalks is shown as 29,775 sf (Section
IV, 10, "On -site Sidewalks" Line of the Application) and as 8,705 sf
(Supplement-EZ Form, Drainage Areas Page, DA 1 Column, Line 12, Sidewalk).
The BUA allocated to non -subdivided "other" is shown as 32,970 sf (Section IV,
10, "Other on -site" Line of the Application) and as 0 sf (Supplement-EZ Form,
Drainage Areas Page, DA 1 Column, Line 12, Other). Please also clarify what this
other BUA is.
3. Please correct the following issues with the Supplement-EZ Form:
a. Cover Page:
i. Line 7 — Per the Goose Creek Watershed Rules, riparian buffers are
required within 200 feet of waterbodies within the 100-Year Floodplain
and within 100 feet of waterbodies that are not within the 100-Year
Floodplain (15A NCAC 02B .0605). NOTE: The buffer requirements for
the Goose Creek Watershed Rules are implemented by the Division of
Water Resources (DWR).
b. Drainage Areas Page:
i. Entire Site Column, Off -site Area. Please clarify what the off -site portion
of the entire site is. Typically, there are no off -site portions to the entire
site since the entire site is comprised of the entirety of the site (The
"drainage area" of the entire site is the project area).
c. Wet Pond Page:
i. Line 5 — This value refers to the vegetated side slopes of the SCM
(required to be 3:1 or flatter per General MDC 3).
ii. Line 8 — The outlet structure functions as an overflow/bypass for flows in
excess of the design volume.
iii. Line 35 — See latter comment about the design volume for this SCM.

iv. Lines 36 - 39 — Per the plans, the outlet for this wet pond is the 3"
drawdown orifice, not the weir.
v. Line 48 — Per the plans, the drawdown orifice draws down from below the
permanent pool elevation
4. Using the provided stage -storage table, the minimum required treatment volume, 45,637
cf, would pond at an elevation of approximately 683.56 (The stage -storage table shows
the cumulative storage volume at elevation 683.5 of only 43,549 cf) which is above the
invert of the bypass weir located in the outlet structure (24" x 12" weir at elevation
683.5). Strictly speaking, this is allowable and not against the MDCs for a wet pond,
however it is a bad design practice and goes against the spirit of the rules since the design
volume of the wet pond should be stored below any bypass devices and allowed to be
drawn down via the drawdown orifice. This is even more apparent when the chosen
design volume, 303,318 cf, is used. About 80 percent of this design volume is drawn
down by the weir in the first couple of hours while the remaining volume is slowly drawn
down by the orifice in a couple of days (This is acceptable for quantity management but
doesn't really meet the intent of Wet Pond MDC 7). You are not required to change the
weir elevation (since this "intent" is not specified in the MDC and therefore non -
enforceable), but you should not use such a large design volume, especially since you are
not required to provide any additional treatment in excess of the 45,637 cf minimum
required treatment volume.
5. 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:
Jim Farkas
512 N. Salisbury Street, Office 640E
Raleigh, NC 27604
ii. For USPS:
Jim Farkas
1612 Mail Service Center
Raleigh, NC 27699-1612
iii. 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.
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 February 18, 2022, 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 SW3211201 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,
✓_ vl
Jim Farkas
Environmental Engineer
Stormwater Program
cc: Mooresville Regional Office