SW3220803_Response To Comments_20230425

H THOMAS & HUTTON
1020 EUCLID AVENUE
CHARLOTTE, NC 28203 1 980.201.5505
WWW.THO MASAN OH UTTON.COM
April 17, 2023
Attn: Jim Farkas
NCDEQ — Division of Energy, Mineral, and Land Resources
Land Quality — Stormwater Program
512 N. Salisbury Street
1612 Mail Service Center
Raleigh, NC 27699-1612
Re: Cresswind Wesley Chapel — Phase 4
Storm Water Review
Monroe, NC
J-27842.0004
To whom it may concern:
This letter serves as acknowledgement that we have revised the previously submitted package to
address all comments below as follows:
- Prior Comment — Please upload the submitted plan sheets individually under the appropriate
file types, not as a single file.
o What was provided: A PDF containing 81 plan sheets uploaded as "Grading/Drainage
Plan"
o What is expected: Multiple smaller PDFs containing relevant subsets of the 81 page
planset uploaded under the appropriate file types. This project will probably use file
types such as cover sheet, existing conditions/survey, proposed conditions/site plan,
existing drainage areas, proposed drainage areas, SCM details, miscellaneous details,
etc... and each file should only have a couple of plan sheets included in it. Laserfiche (the
software that we use for the electronic file uploads) renames & categorizes the
uploaded files based on the file type selected and has issues with large files so that is
why the plan set needs to be broken down in this manner.
■ PDF's will be uploaded in the manner stated above.
- Application:
o Section IV, 8 —The provided percent BUA for the entire site is shown as 54% whereas
this value is shown as 55% in the Supplement-EZ Form. Based on the provided
information (project area of 49.19 ac, New BUA of 27.03 ac, and no existing BUA = 55%),
the Supplement-EZ Form appears to be correct. Please revise as needed.
■ BUA is updated to 55%
o Section IV, 10, % Impervious Area — The percent impervious area for the drainage area
to the SCM as shown (55%) does not appear to correspond to the information provided
for the SCM drainage area (drainage area of 42.25 ac, New BUA of 27.03 ac, and no
existing BUA = 64%)/the information shown in the calculations (64%). Please revise as
needed.
■ BUA is updated to 64%
Supplement-EZ Form:
o Cover Page:

■ Prior Comment — Line 2 — Please use the project area (found in Section IV, 7 of
the Application (which does not include the on -site surface water area)) instead
of the total project area (per Section IV, 4 of the Application (which does include
the on -site surface water area))
• The project area has been updated to reflect 49.19 ac
o Drainage Areas Page:
■ Line 10, Roof— Line 10 is a breakdown of all of the BUA that is not allocated to
an individual lot (i.e., located in the common areas). Roof area allocated to the
individual lots should be shown on Line 6 (as is done on the form), but not
shown on Line 10. The Line 10 Roof BUA type would be used for common roof
areas, such as for an amenity center or other common area building. The items
of Line 10 should add up to Line 7, and, for this project, the sum of Lines 6 & 7
should equal Line 5. Please revise as needed.
• Line 10 has been readjusted to not count twice.
Pond 5 Column, Line 16 — Please revise this item (see earlier comment).
• Line 16 has been updated to reflect 55% BUA
o Wet Pond Page:
■ Prior Comment — Line 9 —The provided detail does not appear to indicate a
drawdown orifice that could be used to dewater the entire pond. The response
to this comment indicates a DIP & sluice gate have been added to the detail, but
these items do not appear to have been provided on the detail on plan sheet
C3.29 (If I missed it, please let me know).
• Detail has been added to plan sheet c3.29
■ Line 25 — The temporary pool elevation is typically set by the invert of the
lowest bypass elevation of the SCM (the weir @ 576.40'). Please revise.
• The elevation has been revised to 576.40'
Line 34 — The cleanout depth of the forebay is the distance from the permanent
pool surface elevation (574.5') to the top of the sediment storage zone in the
forebay (570.0') expressed in inches.
• The depth has been adjusted to 54"
Line 35 — The design volume of the SCM is the volume that can be stored above
the permanent pool surface elevation and below the temporary pool surface.
NOTE: More recent versions of this form make a distinction between the
minimum required treatment volume and the provided design volume of an
SCM (the minimum required treatment volume is determined from the drainage
area to the SCM (provided for this item), typically using the Simple Method,
whereas the design volume is the treatment volume actually provided in the
SCM). Please revise. Per the provided stage storage table, the storage volume
provided above the permanent pool and below 576.40' is approximately 98,000
cf.
• Temporary pool volume elevation has been revised to 576.22' per
comment.

We look forward to receiving the approved certification for the referenced project toallow
us to proceed. If you have any questions, comments, or desire additional information,
please contact our office at [phone].
Sincerely,
THOMAS & HUTTON
"---O� ; �'�
Matthew S. Kiker, PE
MSK