SW6220101_Response To Comments (RECOVERED)_20231113

site
solutions
November 13, 2023 civil engineering I land surveying
NCDEQ Division of Water Quality an
Attn:Jim Farkas
512 N. Salisbury Street
Raleigh, NC 27604
RE: Storm water revision, Woodshire Subdivision Phase 7 (SW6220101), Harnett County, North
Carolina
Jim;
We received the review comments dated October 10, 2023 for Woodshire Subdivision
Phase 7 revision. The comments have been addressed as noted below.
1. Wet Pond MDC 3— Please ensure that there is at least 6 inches of sediment
storage provided in the forebay near the forebay exit. Per the plans and
submittal documents, there appears to be zero inches of sediment storage
provided (see attached comparison to the previously approved design). Please
revise as needed. Updated and revised plan enclosed
2. Please address the following issues with the Wet Pond Page of the Supplement-
EZ Form:
a. Line 25—The temporary pool elevation is determined by the invert of the
lowest bypass device (weir at elevation 289.4' per plan sheet C-6.2).
Please revise. DONE, note: changes resulted in new weir elevation at 289.55'.
All comments addressed using this elevation
b. Line 35—The design volume is based on the temporary pool (see prior
comment). Please revise. Done
c. Line 44—See Wet Pond MDC 3 comment. Please revise. Done
3. Please revise the temporary pool elevation on the 0&M Agreement form (see
earlier comment). Done
4. Please revise the drawdown calculations to take the revised temporary pool
surface elevation and design volume into account. Done
5. While design volumes in excess of the minimum required treatment volume are
acceptable, the pond and drawdown orifice should be configured in such a
manner that allows both the minimum required treatment volume and design
volume to be drawn down within the stipulated 2-5 day window per Wet Pond
MDC 7. This isn't strictly specified in the rules, but it does prevent wet ponds
from being too oversized for their drainage area. It is recommended to slightly
reduce the size of the drawdown orifice or reconfigure the bypass weir in the
outlet structure for the wet pond to allow the minimum required treatment
volume and design volume to drawdown within the 2-5 day window (a 3.0"
409 Chicago Drive, Suite 112, Fayetteville, NC 28306
office 1 910-426-6777 fax [phone]
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diameter drawdown orifice appears to accomplish this objective). Please revise
as needed. Done
6. In accordance with G.S. 143-214.7(c5)(1b), the Division is requiring that a permit
transfer application be submitted for this project within 90 calendar days since
the property has been sold (see attached deed). Please also see permitting
condition 14. The permit transfer application is attached.
Two copies of the revised plan sheets are enclosed as well as a copy of all revised
documents. This data has also been uploaded as requested. I look forward to working
with you on this project. If you have any questions or comments, please contact me at
your earliest convenience.
Sincerely,
4D Site Solutions, Inc
Scott Brown, PE
[e-mail]
Enclosure
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