SW6231105_Response To Comments_20240701

XX OOten 120 N. Boylan Avenue
Raleigh, NC 27603
[phone]
HILTON HEIGHTS 72 UNIT RELOCATION
ROBESON COUNTY
LUMBERTON, NORTH CAROLINA
SW6231105
NCDEQ COMMENT RESPONSE:
1. Prior Comment 2.e. - "NOTE: Since the SCM zone sizes are based on the temporary ponding
surface elevation and there are issues with the portions of the SCM that fall into each zone,
Stormwater Wetland MDCs 6 -9 will need to be reevaluated. Please ensure that the contours
associated with the top and bottom of each zone are included in either the grading plan or
the landscaping plan. 1'The planting zones of the southern part of the stormwater wetland
do not appear to be accurate,please see below. Please revise as needed.
The highlighted area was intended as conveyance and not included in the surface area/design
volume calculations.The channel leading to the wetland in this highlighted portion has been revised
such that the shallow water and temp.inundation zones do not extend into the channel. See email
correspondence with Michael Lawyer dated 6/25/24.
2. Prior Comment 3 - "As designed,this project does not meet Runoff Treatment(defined in
15A NCAC 02H .1002(43] and required per 15A NCAC 02H,1003(3)(a)) ...Please revise as
needed."The submittal items indicate 16,298 sf of BUA are not being captured and treated
in the SCM. Some,if not all, of this BUA(particularly the future BUA that will be used for the
proposed buildings] should be able to be captured and directed to the SCM for treatment. If
the uncaptured BUA is reduced to the maximum extent practicable and there are still areas
of uncaptured net BUA,the uncaptured areas of the site can be permitted as a low-density
area (provided that the area meets the low-density requirements]. Please revise the
submittal materials as needed.
Per our conversation with NCDEQ reviewer Michael Lawyer,the previous submittal shows a Phase
II layout that was 100% conceptual. A portion of this Phase II layout was not included in the
delineated drainage area to the SCM because we did not anticipate it physically being able to
discharge to it due to limited topography. The outline of the Phase II Layout has been removed from
the drainage area plan set to avoid confusion and a maximum of 82,502 SF/1.89 AC has been
accounted for in the current SCM design as"Future BUA". If for some reason the BUA proposed in
Phase II exceeds this maximum impervious area or portions of it will not be routed to permitted
SCM,an additional SCM will be designed as part of that phase to meet current regulations.

XX OOten 120 N. Boylan Avenue
Raleigh, NC 27603
[phone]
3. Prior Comment 5.d. - "Please revise the Supplement-EZ Form (Cover Page and Drainage
Areas Page) to reflect the on-site surface water area and vegetated setback." Please ensure
that the surface water area is excluded from Lines 5 &6 of the Entire Site Column of the
Drainage Area Page.NOTE: Please also exclude the on-site surface water area from any low-
density drainage areas in the Application Form or Supplement-EZ Form.
Supplement-EZ Form lines 5&6 have been updated to exclude SW(0.50 ac) from the areas.Drainage
area exhibits and the application form have been updated too.Total drainage area 30.34
ac/1,321,496 sf.
4. Prior Comment 7.a.iii.- "Please correct the following issues with the Supplement-EZ Form...
Cover Page... Lines 7-9- Please answer these items." Per the provided drainage area map in
the calculations,it appears that a portion of the future BUA will be located within the
vegetated setback. Please be aware that a building is not one of the exempt types of BUA
allowed within the vegetated setback.Since the location of future BUA is not required to be
provided during this step of the review/approval process,this item will not prevent the
permit from being issued,however,please be aware that all of the applicable rules will need
to be met once the future BUA location and layout is known and the permit is modified to
reflect this. No further action required at this time.
Understood.
5. Prior Comment 7.b.i. - "...Drainage Areas Page... Lines 3-4- See earlier comment." See earlier
comment. If you are adding a low-density drainage area to this project,you need to include
the low-density drainage area on the Drainage Areas Page and the Low-Density Page of the
form. NOTE: Don't forget to exclude the on-site surface water area from the low-density
area.
We are not proposing to add a low-density area to this project.
6. Prior Comment 7.h.ii. - "...Entire Site Column -The entire site column is an accounting of the
entire project area (similar to how the drainage area column is an accounting of the areas
that drain to the SCM).When asked for the "drainage area" of the entire site,please enter the
project area." Please ensure that the on-site surface water area is excluded from the entire
site "drainage area"value.The "drainage area"value should correspond to the value shown
in Section IV, 7 of the Application(in square feet).

‘Iv JL1 L n 120 N. Boylan Avenue
Raleigh, NC 27603
[phone]
Understood.This has been updated.Total drainage area 30.34 ac/1,321,496 sf.
7. Prior Comment 7.b.iv.- "... Drainage Area Column, Line 20- Please provide a calculation
showing how this value was determined (see earlier comment with regard to design
volume)." Per the provided stage-storage table,the design volume (volume that can be
stored between the permanent pool surface and the invert of the lowest bypass device is
16,967 cf. Please revise as needed.
The WQV was input incorrectly on the previous submission.The Stage Storage table from the
HydroCAD results was correct.The EZ-Form has been updated.
8. Prior Comment 7.c.i. - "... Stormwater Wetland Page... Line 2 - Please provide a calculation
showing how this value was determined.Typically,the minimum required treatment
volume is calculated using the Simple Method or the Discrete NRCS Method (See Part B of
the Manual for more information)." Per the provided calculations,the minimum required
treatment volume for this SCM is 16,908 cf. Please revise as needed.
This cell was incorrectly entered.The correct volume of 16,908 cf has been entered.
9. Prior Comment 7.c.iii.- "... Line 18 -This value should correspond to the value on Line 20 of
the Drainage Areas Page." See earlier comment with regard to the design volume of the SCM.
Corrected.
10. Prior Comment 7.c.xi. - "... Lines 46-48 These refer to the lowest bypass device (typically,
only orifice or weir is selected)." My apologies,my guidance provided in the prior request
for additional information letter was incorrect for these items.These items refer to the
drawdown device configuration for the SCM,not the bypass device configuration. Per the
design,there are two, 1.75"diameter,drawdown orifices provided in the outlet structure, so
the previously provided value for Line 46 (2x-1.75") should be used and Lines 47&48
should be blank since the drawdown device is not a weir.Sorry for the confusion.
Understood.This value has been changed back.
11. Prior Comment 7.c.xii. - "... Line 49 - Please provide calculations showing how this value was
determined.NOTE: The drawdown time is determined for the design volume of the SCM
based on the temporary ponding surface elevation,see Part B of the Manual for more
information."The provided calculations indicate a drawdown time of 2.22days (NOTE: The
design volume used in this calculation should correspond to the design volume of the SCM,

XX OOten 120 N. Boylan Avenue
Raleigh, NC 27603
[phone]
see earlier comment,revise as needed)whereas this item is shown as 4.2 days. Please revise
as needed.
Understood.The correct draw down time has been added to the EZ-Form
12. Prior Comment 8.- "Please complete the Operation and Maintenance Agreement(O&M EZ
Form].This form is located at the following address:
https:www.deq.nc.gov/about/divisions/energy-mineral-and-
landresources/stormwater/stormwater-program/stormwater-design-manual This item is
required per 15A NCAC 02H .1050(11)." It is noted that the provided form was previously
provided,however the provided form is an outdated and no-longer accepted version of that
form. Please use the provided link to access the current version of that form and provide an
original signed and notarized copy,as well as an electronic copy of that form.While not
required,you may wish to get a second copy of that form notarized for the applicant's
records as an original copy will be required for recording with the County Register of Deeds.
Please revise as needed."
An updated copy of the O&M agreement is included with this submittal.
13. Prior Comment 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. " Please upload the electronic files from the prior
submission to the following link: https://edocs.deq.nc.gov/Forms/SWSupplemental-Upload
Electronic copies are required per 15ANCAC 02H .1042(2).NOTE: Only an electronic copy of
the Supplement-EZ Form was uploaded,the other files were not uploaded.
All files from the previous submittal have been uploaded.
14. Stormwater Wetland MDC 6 - Per the plans,the forebay entrance is too deep.The plans
indicate that the forebay is 42" deep at the entrance and the MDC requires the depth of the
forebay to be between 24"and 40". Please revise as needed.
Forebay entrance depth has been changed to 40". The entrance elevation is now 129.67'.
15. Please provide a Response to Comments letter indicating,in a point-by-point manner,how
each of the above comments has been addressed.This item is required per 15A NCAC 02H
,1042(3)(b)
Noted.See comment response letter.

XX OOten 120 N. Boylan Avenue
Raleigh, NC 27603
[phone]
16. 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
Noted.
b. Hard copies must be mailed or delivered to the following address:
Noted.
Thank you,
Please reach out to Justin Bright,[e-mail], with any questions.

Justin Bright
From: Lawyer, Mike <[e-mail]>
Sent: Tuesday,June 25, 2024 9:23 AM
To: Ana Wadsworth
Cc: Justin Bright
Subject: RE: [External] FW: SW6231105- Hilton Heights 72 Unit Relocation SWM Permit
Follow Up Flag: Follow up
Flag Status: Flagged
Ana,
Just realized that Jim is on leave today,will be attending/presenting at the MDC workshop at NCSU on Wednesday
and Thursday, and will then be on leave until his official last work on July 11th
Regarding comment 1 below, I believe the issue is as we discussed yesterday with respect to the
contours/elevations of portions of the conveyance swale being the same (or lower?) as the SCM footprint,which
would indicate some level of treatment within the swale creating planting zones. My recommendation would be to
clearly summarize or depict in the resubmittal that the swale is intended for conveyance only OR go ahead and
show appropriate/reasonable plantings within the swale.
Michael Lawyer, CPSWQ
Stormwater Program Supervisor
Division of Energy, Mineral and Land Resources
North Carolina Department of Environmental Quality
Office: [phone] I Cell: [phone]
Email: [e-mail]
512 North Salisbury Street, Raleigh, NC 27604 (location)
1612 Mail Service Center, Raleigh, NC 27699-1612 (mailing)
V
E �S
o.wrrn m c «n..rr orrq`��
Email correspondence to and from this address is subject to the North Carolina Public Records Law and may be disclosed
to third parties.
From: Ana Wadsworth <[e-mail]>
Sent: Monday,June 24, 2024 3:02 PM
To: Lawyer, Mike<[e-mail]>
Cc:Justin Bright<[e-mail]>; Farkas,Jim J <[e-mail]>
Subject: [External] FW: SW6231105- Hilton Heights 72 Unit Relocation SWM Permit
Importance: High
CAUTION: External email. Do not click links or open attachments unless verified. Report suspicious emails with the Report Message
button located on your Outlook menu bar on the Home tab.
Good Afternoon Mike,
1