SW3220803_Response To Comments_20221223

H THOMAS & HUTTON
1020 EUCLID AVENUE
CHARLOTTE, NC 28203 1 980.201.5505
WWW.THO MASAN DH UTTOWCOM
December 13, 2022
Attn: Jim Farkas
NCDEQ - Stormwater
610 East Center Avenue, Suite 301
Mooresville, NC 28115
Re: Cresswind - Phase 4
Union County, 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:
1. Please QA/QC the submission. There were a number of issues that prevented a complete
review of the project (I reviewed as much as I could based on what was provided, but
there may be other comments that come up when the submission is corrected). Some
notable examples are provided below:
a. Please clarify the BUA accounting for this project... Please revise as needed so it
is clear what the proposed BUA for this project is.
BUA calculations have been revised and clarified throughout the plan set.
b. The calculations show 23.0 ac (1,001,880 sf) of BUA draining to the SCM while
the Application shows 1,137,965 sf and the Supplement-EZ Form shows
1,840,410 sf.
BUA calculations have been revised and clarified throughout the plan set.
c. The provided cross-section details on plan sheet C3.29 do not appear to
correspond to the grading plans (for example, the cross-section shows the
permanent pool surface elevation at 567.0' while the other submittal items
indicate 574.5', the drawdown orifice is shown on the plans to be 3" and 4" in the
other submittal materials, etc...).
BMP plan has been updated to match grading/calculations.
d. The number of lots associated with this project is shown as 143 in the narrative
and Application (Section IV, 10), however the plans show 144 (Lots 371 to 514
are part of this phase).
Updated lot count.
e. The plan view of the wet pond does not show the forebay.
Forebay has been added to the plans.

2. Please provide calculations showing that the inlet and outlet protection is adequately
sized (General MDC 4).
Revised per comment. Erosion Control report included in this resubmittal.
3. Please exclude the sediment storage zone from the main pool and forebay volume
calculations (Wet Pond MDCs 1, 2, 3, & 5). 1 can't say for sure if this is an issue since
the provided cross-section view of the pond has the wrong elevations, but it appears to
be the case based on the other provided submittal items. Please revise as needed.
Revised per comment.
4. As designed, the forebay is too large (Wet Pond MDC 5a). Using the provided forebay
and main pool volumes from the stage -storage tables (see earlier comment, these
values will need to be revised to exclude the sediment storage zone however this issue
still appears to be present when this is taken into account) of 28,375 cf and 134,764 cf
respectively results in a forebay that is 21% the size of the main pool (28,375 cf / 134,764
cf = 21 % > 20%). Please revise as needed.
5. Please correct the following issues with the Supplement-EZ Form:
a. Cover Page:
i. Line 2 - The Project Area value shown (107.1 ac) does not correspond to
the project area value shown in Section IV, 7 of the Application. Please
revise as needed.
Revised per comment
b. Drainage Area Page:
i. It is strongly recommended to use the latest version of this form (available
on our website. It contains some modifications from the version of the form
that you used, such as providing a line for the total drainage area to the
SCM.
Understood.
ii. Revise the values as needed in accordance with the earlier comment. The
entire site column should be an accounting of the entire site, not just a
sum of the other columns. If any portions of the project area are located
outside of the drainage area to the SCM they should be accounted for in
this column.
Revised per comment.
iii. Lines 17-19 - Please provide these items for the wet pond column.
Revised per comment.
c. Wet Pond Page:
i. Line 9 - The provided detail did not appear to indicate a drawdown orifice
that could be used to dewater the entire pond. Please revise as needed.
DIP Drain pipe and sluice gate added to detail for dewatering purposes.
ii. Line 26 - Per the provided calculations, the surface area of the main pool
is 36,947 sf (39,712 sf is shown).
Revised the provided surface area to match calculations.

iii. Lines 27, 28, & 32 - These items will need to be recalculated (to exclude
the sediment storage zone).
iv. Line 28 - Per the provided calculations, the average depth is 3.97 ft (4.78 ft
is shown). Please revise as needed.
Revised per comment.
Please reupload the plan sheets from the last submission for this project individually
under the appropriate specific file types ("Plansheet - Cover Sheet", "Plansheet -
Grading/Drainage Plan", etc...). Laserfiche does not handle large files (such as an entire
plan set) well. NOTE: We do not require a full plan set (either electronic or hard copy)
you only need to provide the plan sheets needed for us to complete the review.
Will reupload as requested
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
The requested documents will be included in resubmittal
We look forward to receiving the approved certification for the referenced project to
allow us to proceed. If you have any questions, comments, or desire additional information, please
contact our office at [phone].
Sincerely,
THOMAS & HUTTON
Matthew S. Kiker, PE
MSK