SW4210601_Response To Comments_20221026

KENNERLY
ENGINEERING & DESIGN, INC.
October 25, 2022
Jim Farkas
Environmental Engineer
Dept. of Environmental Quality
Division of Energy, Mineral &
Land Resources Stormwater Program
512 N. Salisbury Street
1612 Mail Service Center
Raleigh, NC 27699-1612
RE: Additional Information Request
Stormwater Permit No. SW4210601
Wynnfall Subdivision — Phase One
Davidson County
Mr. Farkas,
Attached are Kennerly Engineering & Design, Inc. (KED) responses of additional information to
comments from your review requested April 261h, 2021, concerning Permit Application submitted
and received February 171h, 2022.
The comments and responses are in the order of the letter received.
Should you have any questions, please do not hesitate to contact us at 336.775.2118.
Sincerely,
Timothy S. Kennerly, PE
Senior Engineer
[e-mail]
Phone:[phone]
12133 N. HWY 150, Ste. F Winston-Salem, NC 27127 Fax: [phone]
www.kennerlyengineering.com

2 /P a g e WYNNFALL SUBDIVISION PHASE ONE STORMWATER PERMIT MOD
PERMIT #SW4210601 - REQUEST FOR ADDITIONAL INFORMATION
ADDRESS: HINKLE LANE, LEXINGTON, NC / DAVIDSON COUNTY
Stormwater Review Comments (received April 26th, 2022)
Comment 1
"Prior Comment 2 — "Please complete the drainage area table on Page 3 of the SWU-101
Application... [15A NCAC 02H.1042(2)(a)J. " For a low -density project, the
`drainage area' is equal to the total project area (Section IV, 7) and there are typically no
off -site components to the `drainage area' (This is the correct form, but the form is set up
for high -density projects, so it can be a bit confusing). The proposed impervious area
within the `drainage area' (shown as 304,920 sf) does not equal the sum of the individual
BUA types listed in the lower half of the table (293,460 sf). The provided narrative states
that each of the 47 lots is allocated a total of 4,847 sf of BUA (total of 227,809 sf)
however, the on -site building/lots value only shows 141,000 sf of BUA. Please revise as
needed"
Response 1: Have revised the Drainage Area to the limits of the project of 29.20 AC.
Comment 2:
"Prior Comment 4 — "Please submit an O&MAgreement, O&MPlan, and Supplement-
EZ Form... [15A NCAC 02H.1042(2)6F)J. " Both the O&M Agreement Form and Supplement-
EZ Form can be found at the following location:
https :Hdeq.nc. gov/about/divisions/energy-mineral-and-landresources/
stormwater/stormwater-program/stormwater-design The provided Supplement
form is an outdated version of the form that we no longer use. Please use the latest
version of this form and provide an original ink signature on the hard copy (NOTE: The
latest version of the Supplement-EZ form has a low -density option that should be used
for this project (The vegetated conveyances can be designed to the treatment swale
standards, however, this is not required. Please only label the vegetated conveyances as
treatment swales if the design standards in 15A NCAC 02H .1061 are being used)).
Please provide an O&M Agreement Form. It is noted that most of the vegetated
conveyances will be located within the DOT ROW, but the maintenance of these
vegetated conveyances is the responsibility of the permittee(s) (similar to how individual
home owners are required to shovel snow off their sidewalks and mow the bit of grass in
front of their house even though these areas are within the right-of-way). Please ensure
that both forms have all of the requisite pages (the forms use macros to generate the
correct pages based on information entered into the cover page. The Supplement-EZ
Form should have 3 pages (Cover, Drainage Area, and Low -Density Pages) and the
O&M Agreement Form should have at least 2 pages (Cover and Low -Density
Maintenance Requirement Pages)."
Response 2: Have attached the O & M Agreement, Supplement EZ Form
Comment 3:
"Prior Comment 5 — "Please provide PDFs of all revisions... " Please ensure that all of
the electronic files for this project are uploaded through the provided link. It appears as
though the USGS topographic map was not uploaded (The Supplement-EZ Form was not
uploaded either, but since it needs to be revised, please just upload the revised version)."
I■
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KENNERLY
EHGAEFBMW s CESAW & C.
12133 N. NC HWY 150, 5€e. F
Winston-Salem, NC 27127
Phone: [phone]
Fax: 336.76.D797
www.kennerlyengineering.com

3 IP age WYNNFALL SUBDIVISION PHASE ONE STORMWATER PERMIT MOD
PERMIT #SW4210601 - REQUEST FOR ADDITIONAL INFORMATION
ADDRESS: HINKLE LANE, LEXINGTON, NC / DAVIDSON COUNTY
Response: Will ensure that all files have been uploaded
Comment 4:
"Please correct the following issues with the Application:
a. Section III, lc — Per the provided property deed, the Applicant, BBJ Building,
Inc., is the Developer only for this project (The Property Owner is listed as Buel
Barker). It is noted that Buel Barker has signatory authority for BBJ Building,
Inc., however they are distinct entities. Please revise this section to exclude
"Property Owner"."
Response 4a: Have revised the application to exclude "Property Owner".
b. Section III, 2 — As noted above, the Property Owner for this project is Buel
Barker, not BBJ Building, Inc., please revise.
Response 4b: Have revised the application per comment
Section IV, 10 — See earlier comments.
Response 4c: Have revised the Drainage Area to the limits of the project
of 29.20 A C.
Comment 5:
"Please correct the following issues with the provided plan set:
a. Please clearly dimension the extents of the project area with bearings and
distances in the main set of plans. This item is required per Section VI, 8i of the
Application and 15A NCAC 02H .1042(2)(g)(ii). It is noted that there are some
bearings and distances provided in the plans, however, it is unclear if the project
area will include the entire parcel (31.11 ac) or a subset of that area. NOTE: The
current Property Owner will remain a permittee as long as the Property Owner
owns property that is covered under the permit."
Response 5a: Have added bearings and distances for the 29.20 A C for this
application.
b. "Please include the type of grass that will be used for the vegetated conveyances on
the vegetated conveyance detail. This item will be used to verify the maximum
allowable velocity for the vegetated conveyances (per 15A NCAC
02H .1003(2)(c)(ii)) and is required per Section VI, 81 of the Application."
Response 5b: Tall Fescue grass will be used in the roadside ditches
"Please clearly delineate any on -site wetlands in the main set of plans or if there
are no wetlands located on -site, place a note in the main set of plans indicating
that there are no wetlands on -site. This item is required per Section VI, 8m of the
Application and per 15A NCAC 02H .1042(2)(g)(iii). Please also include a note
on the plans stating the name and qualification of the individual that made this
determination."
!44
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KENNERLY
ENG894E MW i aESJG+K &C.
12133 N. NC HWY 150, 5€e. F
Winston-Salem, NC 27127
Phone: [phone]
Fax: 336.76.D797
www.kenneriVengineering.com

4 IP a g e WYNNFALL SUBDIVISION PHASE ONE STORMWATER PERMIT MOD
PERMIT #SW4210601 - REQUEST FOR ADDITIONAL INFORMATION
ADDRESS: HINKLE LANE, LEXINGTON, NC / DAVIDSON COUNTY
Response 5c: Will place a note on the plan that no wetlands on the site.
d. Please include plan sheet with the drainage areas to the vegetated conveyances in
the main set of plans (It is noted that this plan set is provided in the report,
however, the rules specify that it must be included as part of the main plan set).
This item is required per Section VI, 8o of the Application and 15A NCAC
02H .1042(2)(g)(iv).
Response 5d: Have added Drainage Area Maps to the back of the plans.
Comment 6:
"Please correct the following issues with the design:
a. As designed, vegetated conveyances 5, 9, 10, 12, 13, 15, 19, and 21 may have
erosive velocities. Per 15A NCAC 02H . 1003 (2)(c)(ii), vegetated conveyances
must be designed in a manner that does not result in erosion during the 10-year
design storm. These vegetated conveyances have 10-year velocities over 4.5 fps
which may be erosive depending on the grass type and underlying soils (We
provide a table of maximum acceptable velocities for different grass and soil
combinations in Part C-11 of the Manual (You may use different values if you
like as long as you provide a source for them). Please include these maximum
allowable velocities in the calculations. NOTE: Using matting to provide erosion
resistance is only acceptable if the matting is permanent (i.e., the vegetated
conveyance must be stable during the 10-year storm in perpetuity)."
Response 6a: The velocities for the above referenced vegetated conveyances
are based on a bare earth condition for the erosion control permit,
A revised calculation for the vegetated conveyances with a grass
lined ditches are attached
b. "Please provide calculation showing that the natural channel downstream of
vegetated conveyance 21 will remain stable during the 10-year design storm
(Required per 15A NCAC 02H . 1003 (2)(c)(ii)."
Response 6b: Have added a calculation for the natural channel downstream of
Ditch No. 21
"The calculations show vegetated conveyance 21 as having a drainage area of 6.26
ac (back -calculated from the provided flowrate, Q = 23.22 cfs, C = 0.54, & I =
6.87 in/hr), however, the sum of the contributing drainage areas (DAs 5-8 and DA
21) is 7.4 ac. Please revise as needed."
Response 6c: Have revised the calculations to reflect the total drainage
area of 7.40 AC
d. "There appears to be a low point located at the southeast corner of lot 38. Please
ensure that positive grading is provided."
Response 6d: Roadside Ditch drains around corner and to the North
on Crickets Run.
Phone: [phone]
KE N N ERLY 12133 N. NC HWY 150, Ste. F Fax: 336.76.A797
ENGINEERING s DESIGN. INC. Winston-Salem, NC 27127 www.kenneriVengineering.com

5 /P age WYNNFALL SUBDIVISION PHASE ONE STORMWATER PERMIT MOD
PERMIT #SW4210601 - REQUEST FOR ADDITIONAL INFORMATION
ADDRESS: HINKLE LANE, LEXINGTON, NC / DAVIDSON COUNTY
Comment 7:
"Since the property will be subdivided, please provide a signed deed restriction document
(this document is available at the following address:
https ://deq.nc.gov/about/divi si ons/energy-mineral-and-landresources/
stormwater/stormwater-program/post-construction-program/post-constructi onform s
This item is required per Section VI, 2 & VII of the Application and per 15A
NCAC 02H .1042(2)(k)."
Response 7: Have provided an executed deed restriction
Comment 8:
"The drainage area to culvert 4 appears to be missing from the provided culvert drainage
area map in the calculations."
Response 8: Have added Culvert No. 4 Drainage Area to the
Culvert Drainage Area Map
Comment 9-
"Please clarify who will own the sliver of land south of Wynfall Drive, across the street
from lots 2-5 (Is this part of lot 47 of common area)?
NOTE: While it is not required to have an HOA for this subdivision in order to get a
post -construction stormwater permit, it is strongly recommended. Without an HOA, each
individual Property Owner in the area covered under the permit will be required to be a
co-permittee and every time that an individual lot is bought or sold, the permit will need
to be transferred (which costs $505 per transfer) to include the new Property Owner. For
example, the process of transferring the property from the current Property Owner to the
47 future lot owners will require 47 permit transfers and will cost $23,735 in permitting
fees (in contrast, if there is an HOA, the HOA becomes the permittee and any ownership
changes for the individual lots does not trigger a transfer). In addition, any enforcement
actions that are taken against this project would be taken against all of the permittees
even if only a single lot is the cause of the non-compliance (in contrast, an HOA serves as
a single point of contact for the permit and all enforcement actions would be taken
through them and they could determine who is at fault/responsible). I understand not
wanting to have an HOA for this subdivision (I live in a subdivision where there is no
HOA, but it also pre -dates the post -construction rules so we don't have to worry about
this issue), however, staying in compliance with the permit may end up being more of a
hassle than having an HOA would be."
Response9: The sliver of land south of Wynfall Drive will be part of Lot 47.
The Developer/Owner has decided against the creation of a HOA and
the Contractor who purchases the lots to build on will be required to
update the permit and will also have to update the permit when the
lots are sold to individual homeowners.
With Septic lots the requirements for the Post Storm Water
Construction Permitting should be reviewed on a case -by -case
determination. Recently Davidson County passed a resolution that
all lots in the county are required to be 40,000 SF for Septic lots.
Phone: [phone]
KENNERLY 12133 N. NC HWY 150, Ste. F Fax: 336.76.A797
ENGINEERING 6 DESkA INC. Winston-Salem, NC 27127 www.kenneriVengineering.com

6 IP a g e WYNNFALL SUBDIVISION PHASE ONE STORMWATER PERMIT MOD
PERMIT #SW4210601 - REQUEST FOR ADDITIONAL INFORMATION
ADDRESS: HINKLE LANE, LEXINGTON, NC / DAVIDSON COUNTY
This requirement should negate the requirement for a stormwater
permit as the developments will not achieve 24% BUA.
Comment 10:
"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 640E
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
Response 10a: PDFs of all documents have been uploaded and hard copies are
contained with this document.
K E N N E R LY 12133 N. NC HWY 150, Ste. F P he Fax336.775.211
: 336.76.9797
ENGINEERING & DESIGN. WC Winston-Salem, NC 27127 www.kenneriVengineering.com