SW6221101_email_20230601 (2)

Ft`STATE.
o.
ROY COOPER A
Governor
ELIZABETH S.BISER
Secretary
DOUGLAS R.ANSEL NORTH CAROLINA
Interim Director Environmental Quality
June 1, 2023
Exp Federal, Inc.
Attn: Lorraine Roberts, PE
205 N. Michigan Avenue, Suite 3800
Chicago, IL 60601
AND
Fort Bragg Department of Public Works
Attn: David A. Heins, Environmental Division Chief
2175 Reilly Road Stop A
Fort Bragg, NC 28310-5000
Subject: Second Request for Additional Information
Stormwater Permit No. SW6221101
Fort Bragg,North Carolina Technical Support Annex, PN79439.2
Cumberland County
Dear Mrs. Roberts and Mr. Heins:
The Division of Energy, Mineral and Land Resources (DEMLR), received a Stormwater
Management Permit Application for the subject project on March 28, 2023. A review of that
information has determined that the application is not complete. The following information is
needed to continue the stormwater review:
1. Prior Comment 2— "Please QA/QC the submission for consistency..." The following
consistency items were noted during review (there are other issues listed below in specific
comments too):
a. The information in the table in Section IV, 10 of the Application was not updated in
accordance with the Supplement-EZ and other submittal items. Please revise.
b. The grading plans were not updated to reflect the revised bottom elevations for SCMs
B3, B4, & B5. The latest submittal items indicate that the bottoms of these SCMs are
located at elevation 267.0' whereas the grading plans indicate that the bottom elevation of
the northernmost SCM is 268.0'. Please revise.
c. The proposed site hydrology plan sheet (CE602) was not revised to reflect the revised
drainage of the site (discharge from SCMs B3, B4, & B5 being directed around, instead
of into, SCM A). Please revise this and any other sheets to show this new storm drain
configuration. NOTE: Please also update the riprap design/sizing calculations on this
plan sheet to reflect the new storm drain configuration (required per General MDC 4).
D E Q�� 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 _
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d. The drainage area information for SCMs 4 & 2 on the SWM Pond Drainage Area Map
does not appear to be correct. Per the drainage area map, SCM 4 is not shown to have an
off-site component to its drainage area whereas the drainage area information in the table
indicates that SCM 4 has 5,608 sf of off-site drainage area. Please revise as needed.
2. Prior Comment 3—The following items were noted with the design of SCM A (SCM A
was changed from a Dry Pond to a Bioretention Cell):
a. Please provide a typical section for SCM A. The typical bioretention cell section shown
on plan sheet CG502 is only specified for SCMs B3, B4, &B5.
b. There does not appear to be sufficient separation between the SHWT and the bottom of
SCM A per Bioretention MDC 1. Per the boring log information shown on plan sheets B-
100—B-309, there does not appear to be a SHWT boring located within the footprint of
this SCM (The closest soil boring appears to be B-04 and was excavated to an elevation
of 251.0' so it is unclear where this SHWT value came from). SHWT information should
be based on borings conducted within the footprint of the SCM. Per the information
entered into the Supplement-EZ Form, the SHWT is assumed to be>250' (NOTE: This
should be less than "<" 250', not greater than">" 250'). Per the outlet structure detail for
SCM A provided on plan sheet CG502, the invert of the underdrain line is at elevation
251.0' (NOTE: The stone layer surrounding the underdrain would put the bottom of the
bioretention cell lower than this elevation) which is less than 2.0' above the assumed
SHWT. Please revise as needed.
c. Please specify the elevation of the IWS for SCM A. The provided outlet structure detail
for this SCM does not specify this information. Per Bioretention MDC 4, the top of the
IWS shall set a minimum of 18 inches below the planting surface.
d. Please provide calculations showing the peak attenuation ponding surface elevation for
SCM A. Per Bioretention MDC 3, the peak attenuation ponding surface elevation cannot
be higher than 24" above the planting surface.
3. Prior Comment 4— "...You will either need to provide a stage-storage table for each
bioretention cell or calculate the storage volume as the bottom surface area of the
bioretention cell multiplied by the ponding depth." Neither option appears to be provided.
Per the note on the Supplement-EZ Form, the first option (calculating the provided storage
volume using the cross-sectional areas of the SCMs) appears to be used for determining the
volume of the SCMs, however we require stage-storage tables for the SCMs to verify these
values. If you do not wish to provide stage-storage tables, you can calculate the provided
design volume in a simplified manner(multiplying the bottom surface area of the SCM by
the ponding depth). NOTE: Per the information shown in the calculations, the surface area of
the soil media is shown to be 19,588 sf for SCM A and 2,500 sf for SCMs B3, B4, &B5
whereas the Supplement-EZ Form indicates that the cross-sectional area of the bottom of the
SCMs is larger, 22,556 sf for SCM A, 4,656 sf for SCM B3, 4,656 sf for SCM B4, and 3,783
sf for SCM B5 (bioretention media should be placed below the entire bottom of the SCMs).
Please revise as needed.

4. Prior Comment 6.b.ii.2.— "...The entire site column is an accounting of the entire project
area(similar to how the drainage area columns are an accounting of the drainage area to
the SCMs. When asked for the `drainage area' of the entire site, it is asking for the project
area." The project area as shown in Section IV, 7 of the Application is shown as 17.17 ac
whereas Line 6 of the Entire Site Column only accounts for 15.16 ac (off-site areas draining
onto the project area are not counted as part of the project area in the Entire Site Column).
Please ensure that the entire project area is accounted for in the Entire Site Column.
5. Prior Comment 6.b.iii.2.— "Line 10— This item should be a sum of the items in Line 12"
For SCM A, the sum of the items of Line 12 (25,027 sf, 1,733 sf, 25,222 sf, 31,897 sf, &
153,878 sf) add up to 237,757 sf whereas Line 10 is shown as 237,759 sf. Please revise as
needed.
6. Prior Comment 6.c.ii.— "Line 18—Please include the SHWT elevation. If the SHWT was
not encountered above a certain elevation,please list the lowest boring elevation that the
SHWT was not encountered at. For example, if the boring terminated at elevation 100'
without encountering the SHWT, you can answer `100' or `<100'for this item." The
provided SHWT values use the greater than sign ">" instead of the less than sign "<". Please
revise.
7. Prior Comment 6.6ii.— "Line 22 —See earlier comment." Please refer to earlier comment
about the design volume of the SCMs.
8. Prior Comment 6.c.y.— "Line 30... — This value... does not correspond to the plans or
other submittal documents." Please refer to earlier comment about the revised grading plans.
9. Prior Comment 6.c.vii.— "Line 43—Please clarify how grass/gravel will be used as
pretreatment for the bioretention cells." Please clearly show (or direct the reviewer's
attention to) the gravel areas for the SCMs in the plans. It is noted that the detail on plan
sheet CG502 indicates that 8" of gravel are provided"where shown on plan view"however
the plan view of the SCMs do not appear to show this gravel area. Please revise if needed.
10. Please specify the pond bottom elevation in the outlet structure detail for SCMs B3, B4, &
B5.
11. 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 LISPS:
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.
NOTE: Per Division policy, the next review of this application will be the final review. Failure
to provide the requested information 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.
NOTE: Expedited permit review/approval can be performed through the Fast-Track Approval
Process. The Fast-Track process breaks the Standard review process into two parts,
Authorization to Construct (ATC) and Final Approval. The ATC is essentially an administrative
review, the specifics of the proposed design and calculations are not reviewed at this time, but
rather the concept of the project is evaluated to see if it can be built in a manner that meets all of
the design standards. The issuance of the ATC allows for the impervious areas of the project to
be constructed. Once construction has finished, and before the E&SC permit is closed out, the
second part of the Fast-Track process, Final Approval is applied for. It is at this point that the
design, as actually constructed, is evaluated for compliance with the design requirements. Any
issues with the design would need to be addressed before the project gets approval. While there
is more risk associated with this approval process, the review times are significantly shorter(30
calendar day review cycle for the ATC vs. the 90 calendar day review cycle for the Standard
review process) and requests for additional information are fewer(since the technical aspects of
the project are not reviewed during the ATC). If you are interested in permitting this project
through this method, you will need to see if the project is able to be permitted through this
method (applicability requirements are outlined on the application form and in 15A NCAC
02H .1043(1)), complete the ATC Application (https://www.deq.nc.gov/about/divisions/energy-
mineral-and-land-resources/stormwater/stormwater-program/post-construction-program/new-
permits-permit-modifications), and provide all of the submittal items required per the
Application & 15A NCAC 02H .1043(3). Please note that a project can only be in one review
queue at a time so applying through the Fast-Track Process rescinds the Standard Application for
this project. While a new permit application fee will be required if switching to the Fast-Track
Process, we can cannibalize items that have already been provided for the Standard Application
for a Fast-Track Application (or you can resubmit a complete package, whatever is easiest).
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 July 1, 2023, 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 SW6221101 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,
Jim Farkas
State Stormwater Engineer
DEMLR Post-Construction Stormwater Program
cc: Fayetteville Regional Office