SW1240602_Response To Comments_20241024

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ROY COOPER 11 *. - , (I
Governor '6 ■ :`' O'
ELIZABETH S.BISER ``�` ate f
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Secretary ' *f Zmsiuto*_.`
WILLIAM E.TOBY VINSON,JR NORTH CAROLINA
Interim Director Environmental Quality
September 11, 2024
Equinox
David Tuch
14 O'Henry Avenue, Suite 206
Asheville,NC 28801
AND
Jackson County
Attn: Darlene Fox, Interim County Manager
401 Grinstaff Cove Road
Sylva,NC 28779
Subject: Request for Additional Information
Stormwater Permit No. SW1240602
Jackson County Splash Pad
Jackson County
Dear Mr. Tuch and Ms. Fox:
The Division of Energy, Mineral and Land Resources (DEMLR),received a Stormwater
Management Permit Application for the subject project on June 13, 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. Please provide a copy of the lease agreement between the Property Owner, "Cashiers
Valley Community Council Inc", and the Permittee, "Jackson County" (Section III, 1c).
included this submittal
2. Consistency
a. The information entered in the drainage area column of the Drainage Areas Page of
the Supplement-EZ should match the information provided the Application Section
IV, 10. Both of these items are an accounting of the drainage area to the SCM. The
Supplement-EZ references off-site area being directed to the SCM, but the
Application does not. Ensure that if off-site area is directed to the SCM it is
accounted for at full build out potential per previously provided comments.
Please refer to the manual Chapter B Stormwater Calculations for guidance on
calculating the minimum treatment volume. Due to inconsistencies within the
EZ for first submittal was submitted through portal on accident with all other documents from second
submittal. no-off site is included in drainage are 1. Due to the need to include a LD drainage,
some redesign was done and more BUA was included in D1. All documents should now be consistent
with D1 and LD1.
D
E -' North Carolina Department of Environmental Quality I Division of Energy,Mineral and Land Resources
J/� 512 North Salisbury Street 1 1612 Mail Service Center I Raleigh,North Carolina 27699-1612
NORTH CAROLINA v
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package, it could not be confirmed if the definition of runoff treatment was met,but
the narrative indicates that this method of stormwater treatment is being pursued.
The minimum treatment was verified
Per 15A NCAC 02H .1002 (43) "Runoff treatment" means that the volume of
stormwater runoff generated from all of the built upon area of a project at build-out
during a storm of the required storm depth is treated in one or more primary SCMs or
a combination of Primary and Secondary SCMs that provides equal or better
treatment.
The minimum treatment listed in the calculations is inconsistent with what is shown
on the Supplement-EZ. As the minimum required treatment volume is unclear due to
the inconsistencies, the wetland can not be thoroughly reviewed at this time.
The minimum treatment is 1" and made consistent through document
3. Supplement-EZ Form
lx hard copy of the complete, original Supplement-EZ Form is required per Sections V& VI, 3
of the Application.
a. Cover Page:
i. Line 7—It is noted that there are no surface waters located on-site, however, please
listed list the width of the required vegetated setback form surface waters (per 15A
NCAC 02H .1003(4)( &.1017(10)). You may leave Lines 8-10 as-is since there are
no surface waters located on-site.
b. Drainage Area Page:
i. Entire Site Column
The entire site column is an accounting of the entire site area and shows a breakdown of all of
the on-site BUA(both the BUA that drains to the proposed SCM and the BUA that bypasses the
SCM). Per the definition of Runoff Treatment(15A NCAC 02H .1002(43)), all of the BUA of a
project must be treated in one or more primary SCMs (If it is not possible to direct all BUA to an
SCM, the bypassed area of the project can be permitted as a low-density area,provided it meets
all of the requirements outlined in 15A NCAC 02H .1003(2)).
included a Low Desity (LD1) drainage area and completed all columns as directed
The drainage area column (to the right of the entire site column) should be an accounting of all
of the BUA located within the drainage area to the SCM. NOTE: Lines 19-21 are not required
for the entire site column.
ii. Line 7/Line 11- Off-site BUA must be accounted for at full build-out potential.
This is 100% BUA or a legal agreement is entered into between property owners
limiting the amount of BUA that may be directed to the SCM.
iii. Line 12/Line 15 —Please only account for the 14,780 SF of BUA once on this
column.
iv. Line 19 - 15A NCAC 02H .1002 (40) "Required storm depth" means the minimum
amount of rainfall that shall be used to calculate the required treatment volume or
to evaluate whether a project has achieved runoff volume match.
v. Line 21 —Per the provided calculations, it appears the Discrete NRCS Curve
Number Method was utilized.
ii. off-site is bypassed. iii. adjusted iv. adjusted to 1" v. adjusted to NRCS curve number method
which is what is being used

c. Stormwater Wetland Page
i. Line 43/44: The forebay entrance must be deeper than the forebay exit,please
ensure this is also revised on the plans. Wetland MDC 6.adj. to reflect outfall of forebay
ii. Line 51: WETLAND MDC 4. SOIL AMENDMENTS. The pH, compaction, and
other attributes of the first 12-inch depth of the soil shall be adjusted if necessary
to promote plant establishment and growth. specified
Please specify the pH, compaction, and other attributes on the plans.
iii. Line 53: Per Wetland(13) SHALLOW WATER PLANTINGS. The shallow water
zone shall be planted with a minimum of three diverse species of herbaceous,
native vegetation at a minimum density of 50 plants per 200 square feet
(equivalent to 2 foot on center spacing). calcs. shown on plans and added to EZ
iv. Line 55: Per Wetland MDC (15) DAM STRUCTURE AND PERIMETER FILL
SLOPES. On the dam structure and perimeter fill slopes, non-clumping turf grass
shall be provided; trees and woody shrubs shall not be allowed. adjusted, previously
4. Plans: miss clicked
2x hard copies of revised plan sheets with the following corrections made:
(This item is required per 15A NCAC 02H.1042(2)(g) and per Section VI, 8 of the Application)
a. Please delineate the drainage area to the proposed SCM in the main set of plans (per
15A NCAC 02H .1042(2)(g)(iv)). It is noted that drainage area patterns are provided
however it needs to be clearly shown that the net increase in BUA is directed to the
SCM in order to meet the definition of runoff treatment. adjusted on drainage exhibit
Please ensure the drainage area includes all areas draining to the SCM, including the
area of the SCM itself 15A NCAC 02.1042(2)(a)(iv), .1003, and 1050(1). included
b. Please identify the surface area of all on-site BUA (Section VI, 8j). The surface area
information shown in the application/supplement form of all proposed BUA should
be able to be verified on the plans. Certain regular geometric shapes can be verified
solely based on dimensions whereas areas of irregular shapes cannot easily be
determined solely from the provided plans. You may wish to provided surface area
callouts, add surface areas to existing callouts, or add a table, similar to the one in
Section IV, 10 of the application. included, refer to L0.3
c. Sheet L4.0 indicates that riprap is protecting the inlet of the SCM. Provide class and
sizing specifications that correspond to calculations indicating that the requirements
of 15A NCAC 02H.1050(4) are met.
i. Please provide engineering calculations demonstrating that the inlet of the SCM
will be designed to protect the SCM from erosion resulting from stormwater flow
into the SCM during the peak flow from the 10-year storm event. added to L4.0
ii. Please provide engineering calculations demonstrating that the outlet of the SCM
will not cause erosion downslope of the discharge point during the peak flow from
the 10-year storm event. refer to added compound weir calculations for 10yr in calcs.
d. Please provide the following items per 15A NCAC 02H .1042 (2): (h) signed, sealed,
and dated plan details of each SCM in plan view at a scale of one inch equal to 30
feet or larger and a cross-section view... The plan details shall include: (i)
dimensions, side slopes, and elevations including cleanout elevation ; (ii) all
conveyance devices, including inlet device, bypass structure,pretreatment area, flow
distribution device, underdrains, outlet device, energy dissipater, and level spreader;
and(iii) specification sheets for materials used in the SCM...
added to details to meet requirements

i. Ensure the following elevations are labeled in the detail on the cross section/plan
view:
peak attenuation above temporary pool (if applicable), temporary pool (top of the
temporary inundation zone),permanent pool (top of the shallow water zone),
bottom of shallow water zone, bottom of forebay deep pool at deepest point(at
forebay entrance),bottom of forebay deep pool at shallowest point(at forebay
exit),bottom of non-forebay deep pool at deepest point, and sediment cleanout
elevation. added elevations to plan
5. Calculations:
lx signed, sealed, and dated hard copy of calculations with the following corrections made:
(This item is required per Section VI, 7 of the Application)
a. Please provide a method of verifying that the volume and surface area requirements
are being met such as a stage storage table. Wetland MDC 3, 6, 7, 8, 9 10.
stage storage table was added to calculations package
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). included here
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:
Brianna Holland
512 N. Salisbury Street, Office 640M
Raleigh,NC 27604
ii. For USPS:
Brianna Holland
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.
While not required to be addressed, the following is noted:
- Thermal impacts of SCM discharges is of concern in HQW waters that support trout. The
higher temperatures reduce dissolved oxygen, reduce reproductive rates, hinder growth,

increase disease exposure, and may have other negative impacts. Temperatures are
typically increased due to ponded water being exposed to sunlight.
SCMs that Protect Stream Temperature:
Bioretention
Infiltration
Permeable Pavement
Rainwater Harvesting
Green Roof
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.
Note that this is only a review of the final,post-construction condition, and that temporary
erosion control measures (such as the sediment trap) are not reviewed in the scope of this permit,
and will be discarded.
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 October 11,2024, or
the application will be returned as incomplete. No extensions will be granted. The return of a
project will necessitate resubmittal of all required items, including the application fee. Please
reference the State assigned project number SW1240602 on all correspondence.
The Division is allowed 30 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,
6 4,,,,,,,A0,- ___ k ee.i i
Brianna Holland
Environmental Engineer
DEMLR Post-Construction Stormwater Program
cc: Asheville Regional Office
Please note design changes to account for a Low Density drainage area (LD1) led to:
1. The removal of pipes 1-4,
2. The removal of swales G and H
3. The inclusion of the restroom BUA in the calculations for SCM1
These design changes and impacts, such as swales F and J receiving more flow, are included
and noted in red revision clouds or text in the calculations package.
The implications of this also necessitated a revised application, so that the application,
Supplement EZ, and calcs package were all consistent.