SW4210801_Response To Comments_20220421

q-"­` 4�f D E SI G N �
CL/ENT-FOCUSED • COMPREHENSIVE • COST-EFFECTIVE
April 20, 2022
2537 E. L YON STATION RD, STE 102
PO BOX 361
CREEDMOOR, NC 27522
919 230-0996
Please find below responses to the comments for Holt Farm (20-085) provided on January
13, 2022 in bold green italics:
1. Original Comment 3 - 'Please submit complete Supplement-EZ Form..." Please
correct the Following issues with the Supplement-EZ Form:
a. Drainage Areas Page, Line 12 - Please do not include the BUA that is allocated
to the individual lots for this item as this item is a breakdown of the new BUA
not on subdivided lots. The sum of the values of Line 12 should add up to Line
10. NOTE: The BUA information shown in the Supplement-EZ Form and in
Section IV, 10 of the Application do not match (they should). Please revise as
needed for consistency.
DA page, line 12 has been revised. The BUA information shown in Section
IV, 10 of the application is match, but the BUA percentage has been revised.
b. Low -Density Page:
i. Line 11 - This item is not required since curb outlet swales are not
proposed for this project.
Only two options (yes/no) are available. Hence, the line 11 was filled
with "Yes" option.
ii. Vailow in the Swale Table - Please provide a source for the values used
for this column. We do provide a table of acceptable maximum
velocities in Part C-11 of the Design Manual (you are not required to
use these values, but you can if you like).
The matting design was for NAG-SC150. The chart on sheet C-1.1
correspondence with the published data from NAG (Attached).
2. Please provide an additional, full size hard copy of the plans. This item is required per
Section VI, 8 and 15A NCAC 02H .1042(2)(g). It appears as though only 1 full sized set
and one half sized set were provided during the initial submission and resubmission.
Understood, 2 full size copies and 1 half size copy are now provided.
Please provide a justification foe the inclusion of the conveyance pipe between the
two Phase I lot located north of Ralph Holt Court or revise the design to eliminate the
excessive piping in accordance with 15A NCAC 02H .1003(2). Low -density project are
typically only allowed to use piping when unavoidable (such as for roadway crossings
and when there are erosion control issues. The site appears flat enough to grade the
site in a manner that the swales drain as shown in the attached image (which excludes
this pipe).
The proposed pipe is to provide adequate drainage around the lots as the existing
NCDOT culvert under Mt. Hermon Rock Creek Road is a constraint with elevation
here. Part of our `low impact" design was to minimize grading for the road,
therefore, the road was set to be graded along the existing topo and falling from

2537 E. L YON STATION RD, STE 102
DESIGN
PO BOX 361
CREEDMOOR, NC 27522
If1'.' f�., ,f ' =; � 919 230-0996
CLIENT -FOCUSED • COMPREHENSIVE • COST-EFFECTIVE
the NW to SE. In doing so, the roadside ditch designs, as mandated by NCDOT
achieved a depth at the cross -line locations where the outlet of the 24" culvert
under our new road only has about 3.58' of fall to the existing 24" culvert under
Mt. Hermon Rock Creek Road. The total distance along the lot lines is 388' from
outlet to outlet, which would result in a ditch less than 1 % and good engineering
practice is to have at least 2% fall for grassed swales, especially around homes
where we wouldn't want standing water and mosquito issues. The pipe cannot be
picked up due to the road grades as it already has minimum cover and we had to
get a special exception from NCDOT for that. Raising the entire road, would result
in increased disturbance outside of what we have currently shown. Therefore,
instead of piping the entire run, we ran the ditch as far as we could at 1.5% (still
boarder line but is straight shot and a short segment) with the pipe at 0.5% to
help get the water out. Per email correspondence, this is acceptable.
4. Please show the drainage areas to the proposed vegetated conveyances on the plans.
This item is required per Section VI, 8o of the Application and per 15A NCAC
02H .1042(2)(g)(iv). We also use this information to verify that the swale calculations
are correct. You may also wish to clarify the labels for the vegetated conveyances on
the plans since between plan sheets C-1.1 & C-1.2, "PD-1" refers to two different
swales (PD-1 is perpendicular to the proposed street on sheet C-1.1 and parallel to
the proposed street on sheet C-1.2). While not required, you may wish to add a note
to the Low -density page of the Supplement-EZ Form listing the names used on the
plan sheets for the 6 vegetated conveyances and which swale number on this form
they correspond to.
The pre -development and post -development DA have been provided in C-1.1 and
C-1.2 respectively. DWD-1 and PD-1 outlet to the same location, and PD-1 captures
were more than DWD-1 and therefore is conservative to list as requiring the same
matting as PD-1. Note has been added.
5. 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:.I.Iedocs.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
1612 Mail Service Center
Raleigh, NC 27699-1612
ii. For USPS:
Jim Farkas
1612 Mail Service Center
Raleigh, NC 27699-1612
iii. Hand Delivery:

2537 E. L YON STATION RD, STE 102
"""'DESIGN PO BOX 361
CREEDMOOR, NC 27522
CLIENT -FOCUSED • COMPREHENSIVE • COST-EFFECTIVE 919 230-0996
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.
Understood,
C3 Design & Engineering, PLLC sincerely appreciates the opportunity to respond to these
comments and looks forward to discussing them with you further as needed. Please don't
hesitate to contact me with any further questions or comments you may have.
Regards,
�A
Joel H. Sain, EIT
C3 Design & Engineering, PLLC
ioel(06designeng.com