SW6240205_Response To Comments_20240718

ROY COOPER o
Governor ■I ;—A -
ELIZABETH S.BISER ,; � ;:
Secretary ' f�`ouA„,,,
WILLIAM E.TOBY VINSON,JR NORTH CAROLINA
Interim Director Environmental Quality
May 20, 2024
Crawford Design Company
Attn: Kevin Lindsay, PE
116 N. Cool Spring Street
Fayetteville,NC 28301
AND
Hoke County Board of Education
Attn: Kenneth Spells, Superintendent
310 Wooley Street
Raeford,NC 28376
Subject: Request for Additional Information
Stormwater Permit No. SW6240205
Hoke County High School Replacement
Hoke County
Dear Mr. Lindsay and Mr. Spells
The Division of Energy, Mineral and Land Resources (DEMLR), received a Stormwater
Management Permit Application for the subject project on February 20, 2024. A review of that
information has determined that the application is not complete. The following information is
needed to continue the stormwater review:
1. As designed, this project does not appear to meet Runoff Treatment (required per 15A
NCAC 02H .1003(3)(a)). For a project to meet Runoff Treatment, the net increase in
BUA must be captured and treated in one or more primary SCMs. Please note that the net
increase in BUA is measured from existing conditions to proposed conditions where
existing conditions refer to what existed on-site when the rules went into effect in this
area (not necessarily what currently exists on-site). The current tennis courts appear to
have been constructed sometime between 2011 —2013, after the rules went into effect in
this part of the State, so the BUA associated with them would not count towards the
existing BUA for the site. Approximating the BUA associated with the courts from
satellite imagery results in a net increase of BUA for the site of approximately 3.48 ac
(and the SCMs are only capturing& treating runoff from 3.04 ac). It is recommended to
direct more BUA to the proposed SCMs as there is sufficient storage volume within them
to treat more BUA than is currently being directed towards them. Please revise as needed.
Response: The ex. tennis courts have been removed from the ex. BUA and more
BUA runoff has been directed to SCM 2. The pre and post development maps have
been revised and are attached.
D
E��,- North Carolina Department of Environmental Quality I Division of Energy,Mineral and Land Resources
'-_)) 512 North Salisbury Street 11612 Mail Service Center I Raleigh,North Carolina 27699-1612
NORTH CAROLINA v
Department of Environmentalaeenry 919.707.9200

2. When determining the SHWT elevation or in-situ infiltration rate for an SCM with
multiple provided borings, do not average the measured values, but rather use the more
conservative of the values form the borings. For example, if there are two borings for an
SCM and boring#1 indicates that the SHWT is at elevation 99' and boring#2 indicates
that it is at elevation 101' the SHWT should be assumed to be at elevation 101', not at
elevation 100'. Please revise as needed.
Response: The SHWT values have been adjusted. See SWM calculations.
3. The provided plans are not to scale, see below (required per 15A NCAC 02H .1042(2)(g)
and Section VI, 8.f of the Application). Please revise as needed.
Response: We believe the paper copies may have been printed at the wrong size.
The sheets should be 30 x 42. The scale indicated is correct. Correct size sheets
are attached.Response: The ex. tennis courts have been removed from the ex.
BUA. The pre-development map has been revised and is attached.
• 251.7 • 25 . 2'
I /
0 30 60
4
4. Please correct the following issues with the Supplement-EZ Form:
a. Cover Page:
i. Line 7 -Please include the width of the vegetated setback from surface waters
required per 15A NCAC 02H .1017(10). It is noted that there are no surface waters
located on-site,however we ask that this value be included on this form(Lines 8 &
9 can remain as "N/A"to indicate that there are no surface waters located on-site).
Response: The vegetated setback of 30' is indicated on line 7.
b. Drainage Areas Page:
i. Line 15/Line 22—Please indicate (at least for the entire site column)the amount of
existing BUA that will remain on-site (it does not matter if it will be relocated or
changed from one type of BUA to another). It is understood that this form isn't
really well suited for showing the BUA accounting for projects that are mostly
redevelopment, so if you want to, you can just include the amount of existing BUA
Response: The existing BUA (7.73 ac/336,718 sf) is shown on line 16 and 17 in the
'entire site' column.

for the entire site in the additional information box (and leave the columns as final
BUA allocations by type for each DA/the entire site).
ii. Entire Site Column, Line 18 & Section IV, 8 of the Application—Please note that,
for a site with existing BUA, the existing BUA may be excluded from the project
area percent BUA calculation per 15A NCAC 02H .1003(1)(b). [Percent BUA] =
[Net Increase in BUA] /([Total Project Area] — [Existing BUA]). Please revise if
needed. The percent BUA has been updated on line 18, 'entire site' column and on
section IV 8 of the application. Calculation is shown on additional infomation line 22.
c. Bioretention Cell Page:
i. Line 2—The minimum required treatment volume is calculated using either the
Calculations Simple Method or Discrete Runoff Volume Method for the area draining to the
have been SCM. For example, if the DA to an SCM is 3.37 ac and the BUA draining to the
revised as
indicated. SCM is 2.11 ac,then,using the Simple Method, the minimum required treatment
volume would be 7,505 cf[DV=Rd * Rv * DA * 3630= 1.0" * (0.05 + 0.9*(2.11
ac/ 3.37 ac)) * 3.37 ac * 3630= 7,505 cf]. Please revise as needed.
ii. Line 9— See earlier comment. Correction has been made
Correction has iii. Line 24—The peak attenuation elevation over the planting surface would be
been made, measured from the planting surface (251.0')to the highest ponding elevation
please see details. associated with the design storm(for the 100-year storm for SCM 1, the plans
Ponding elev. are
from routing and show this value as 252.2'). Please revise as needed(it is unclear where the
provided values came
shown in table from). iv. Response: Pine bark fines is shown on the SCM detail
same sheet iv. Line 36—Please specify this information on the plans.
Sheets C302.1 &Cn3 1
v. Please revise the information on the other lines as neede in accordance with the
other comments. plans
corrected
5. Please correct the following issues with the design of the bioretention cells:
a. General MDC 4—Please provide calculations showing that the inlets and outlets of
the SCM are stable in accordance with the MDC.
Rip Rap dissipaters are provided with all inlets (Calculations attached). Outlets are all RCP pipe.
b. General MDC 6—Per the Supplement-EZ Form, the dewatering method is listed as
drawdown orifice, however the detail does not indicate a drawdown orifice capable of
dewatering the SCM. Please revise as needed.
Dewatering method: Screw caps on upturned elbows allow for dewatering.
c. Bioretention MDC 5 —Per the plans, the media layer is shown to be 25" deep whereas
the MDC requires a minimum depth of 30". NOTE: The 2.5' depth shown on the
plans is measured from the planting surface to the bottom of the sand and choking
stone layers. Since the thickness of the sand and choking stone layers is 5", the
remaining depth of the media layer is only 25". Please revise as needed.
Plans have been revised.
d. Bioretention MDC 6—The media mixture percent composition shown in the plans
does not meet the MDC. Per the plans, the fines are specified to be between 10%-
15% (whereas the MDC specifies 8%-10%) and the organics are specified to be
between 5%-10% (whereas the MDC specifies 5%-15% (the provided range is
acceptable since it is within the required range)). Please revise as needed. NOTE:
There is a typo in the Manual with regard to this information. Please refer to 15A
NCAC 02H .1052(6) for the correct percentages.
d. Response: The media percentages have been adjusted on the SCM detail sheets
C302.1, C303.1

e. Bioretention MDC 8—Please include a note on the plans indicating that the media
should not be mechanically compacted.
Response: The note has been added to C302.1 and C303.1
6. 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).
7. 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 640M
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.
To ensure a fair, timely, and transparent review process, any disagreement with provided
comments will need to be addressed in writing as part of the requested information resubmission,
within the required resubmittal window. The merits of the disagreement will be reviewed during
the next scheduled technical review and, if applicable,will be addressed in further requests for
additional information. If the resolution provided by the reviewer is found to be unsatisfactory,
the applicant can agree in writing to a longer review period, during which the dispute will be
brought to the technical review committee and a final determination will be made.
Due to staffing limitations and to ensure an efficient project review, requests for individual
meetings to discuss provided comments are decided at the discretion of the reviewer. We
encourage you to carefully review the written feedback provided and the applicable rules. The
NCDEQ Stormwater Design Manual provides additional insight into design criteria. Any
questions or further requests for clarification should be submitted in writing in the requested
information resubmission, within the required resubmittal window. We appreciate your
understanding and cooperation in this streamlined process.

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 June 19, 2024, 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 SW6240205 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(919) 707-3646.
Sincerely,
IL
LA--
Jim Farkas
State Stormwater Engineer
DEMLR Post-Construction Stormwater Program
cc: Fayetteville Regional Office