SW5221102_Add Info_20230223

Ft`STATE.
o.
ROY COOPER A
Governor
ELIZABETH S.BISER
Secretary
DOUGLAS R.ANSEL NORTH CAROLINA
Interim Director Environmental Quality
February 23, 2023
Stocks Engineering
Attn: Mike Stocks, PE
PO BOX 1108
Nashville, NC 27856
AND
Axiom Development, LLC
Attn: Tom White, Registered Agent
3739 National Drive, Suite 105
Raleigh, NC 27612
Subject: Request for Additional Information
Stormwater Permit No. SW5221102
Bryson's Ridge Subdivision—Phase 2
Nash County
Dear Mr. Stocks and Mr. White:
The Division of Energy, Mineral and Land Resources (DEMLR), received a Stormwater
Management Permit Application for the subject project on November 28, 2022. 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 reach out to the 401Buffer Permitting Branch
(https:Hdeq.nc.gov/about/divisions/water-resources/water-qualit -permitting/401-buffer-
permitting-branch) to see if a permit is needed for the proposed wetland crossing. If
required, please update Section II, 4a of the Application.
2. Please upload the electronic files for this project at the following link:
https://edocs.deq..nc.gov/Forms/SW-Supplemental-Upload.Electronic files are
required in accordance with 15A NCAC 02H .1042(2).
3. The following issues were noted with the general design of the proposed SCMs:
a. Please provide calculations showing that the inlets and outlets of the SCMs are stable
in accordance with General MDC 4.
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512 North Salisbury Street 1 1612 Mail Service Center I Raleigh,North Carolina 27699-1612
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b. Please clearly show the stormwater maintenance access & easement on the plans
(General MDC 8 & 9).
c. The drawdown calculations (Wet Pond MDC 7) should be based upon the design
volume of the SCM (typically the volume that can be stored above the permanent
pool surface elevation and below the lowest bypass elevation). For example, for Wet
Pond#2, the permanent pool surface elevation is at elevation 243.5' and the lowest
bypass elevation is at elevation 245.5' (the weir outlet structure). The provided
calculations use the head value associated with these two elevations (2.0') but they do
not use the storage volume associated with these two elevations (approximately
62,000 cf) when determining the drawdown time. Please revise as needed.
d. This project is located within a Nutrient Sensitive Watershed (NSW). Please ensure
that the SCM reduces nutrient loading in accordance with 15A NCAC
02H .1017(9)(c).
4. The following issues were noted with the design of Wet Pond#2:
a. Please exclude the sediment storage zone from the forebay volume calculation (Wet
Pond MDC 5a). Per the plans, the top of the sediment storage zone in the forebay is
located at elevation 240.0'. Any storage volume provided below this elevation does
not count towards the volume of the forebay. Please revise as needed.
b. As designed, this pond appears to short-circuit (Wet Pond MDC 4). Please relocate
the drawdown orifice further away from the inlets/forebay (see attached for possible
alternative locations) to better maximize the flow path through the wet pond.
c. There appears to be a discrepancy between the vegetated shelf size as shown in the
calculations (5,232 sf with 1,308 plants) and as shown on the plans (4,506 sf with
1,128 plants). Please revise as needed for consistency. NOTE: Both planting plans
meet the minimum required plant density requirement as outlined in Wet Pond MDC
1lb it is just unclear which one is actually being proposed.
5. The following issues were noted with the design of Wet Pond#3:
a. There appears to be an issue with the provided stage-storage tables for the main pool
and forebay. The plans indicate that the permanent pool surface elevation is at
elevation 253.5' whereas the stage-storage tables for the forebay and main pool only
go up to elevation 253.0' and the incremental volume calculation between elevations
252.0' & 253.0' appears to be incorrect. Please revise as needed.
b. There appears to be a discrepancy between the drawdown orifice size as shown in the
calculations (1.5" diameter) and the plans (1.75" diameter). Please revise as needed.
6. Please ensure that the area downstream of FES 205 meets the curb outlet system
requirements outlined in 15A NCAC 02H .1003(2)(d)). Please also revise the portions of
the Low-Density Page of the Supplement-EZ Form related to the curb outlet system.
NOTE: Curb outlet systems can either be swales (as indicated in the Supplement-EZ

Form) or vegetated areas. If using a vegetated area, fill out as much of the Supplement-
EZ Form as possible.
7. The following issues were noted with the Supplement-EZ Form:
a. Wet Pond Page:
i. Line 25 —The temporary pool surface elevation is typically determined by the
lowest bypass elevation (245.5' for Wet Pond#2)
ii. Lines 26-28, Wet Pond#3 Column— See earlier comment with regard to the stage-
storage tables, please revise as needed.
iii. Line 32—See earlier comments.
iv. Line 34—The cleanout depth of the forebay is the distance from the permanent
pool surface elevation (243.5' for Wet Pond#2 & 253.5' for Wet Pond#3) to the
top of the sediment storage zone for the forebay (240.0' for Wet Pond#2 & 250.0'
for Wet Pond#3), expressed in inches.
v. Line 35 —See earlier comment. The design volume is typically the volume that can
be stored above the permanent pool surface elevation and below the lowest bypass
elevation.
vi. Lines 37 & 55 —See earlier comment with regard to the drawdown orifice size.
Please revise as needed.
vii. Line 40—See earlier comment with regard to the drawdown calculation.
b. Low-Density Page:
i. Lines 4 & 15 — Since multiple different cross slopes for the vegetated conveyances
are proposed, please indicate this in the additional information section.
8. 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.
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 March 25, 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 SW5221102 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: Raleigh Regional Office