SW6100701_Response to Comments_20100916

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P.A.
]be E. Godwin Sr., P.E., P.L.S.
Email: generalCenochengiaeers.com
September 16, 2010
Consulting Engineers & Surveyors
NCDENR
NC Division of Water Quality
Stormwater Department
1617 Mail Service Center
Raleigh, NC 27699-1617
1403 NC Hwy 50 South
Benson, NC 27504
Re: Traemoor Connection Site
Cumberland County, NC
Stormwater Project No. SW6100701
Mr. Patterson:
Phone:[phone]
[phone]
Fax:[phone]
NOV 16 2U10
y
FSEP 2 4 2010
We are resubmitting the stormwater plans revised per NCDENR comments dated
8/27/2010. Included are the following items:
a. Two sets of the plans
b. Two sets of the calculations
C. Two supplemental forms
d. One original and one copy of the Deed Restrictions form
Please see the following responses to the comments dated August 271h, 2010 and July
12th, 2010.
1. All out -parcels and their BUAs are listed on the Deed Restrictions form.
2. The revised pond design incorporates a riser and barrel assembly sized to
control the estimated SHWT (see soils report) as well as the required V
storm volume. Given that the SHWT is approximately 2.5' above the
proposed PPE of 173.50, the principle spillway has been designed at 177.00
to allow the 1." storm volume to be controlled within the 2 to 5 day period.
Calculations have been provided for the 1yr, 2yr, 10yr, 25yr, 100yr, and
500yr storm.
3. Drainage Area depiction corrected. The front of duplex lots will slope
toward the street. The rear of the duplex lots shown on the eastern and
southern sides of the project will slope away from the street, minimizing the
amount of drainage not being collected by the pond. Contour Labels are now
shown on the finished grade contours.
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4. Allotted BUAs for the Harris Teeter and CVS sites are now shown on the
deed restrictions form.
5. N/A
6. The site plan and proposed outparcels shown is very preliminary and subject
to change. BUA and impervious area are based upon this site design, but the
design may change with the realization that no impervious area can be
added to any future design. The final detailed site plan will be submitted to
DWQ for approval.
7. NIA
8. The final design of the site plans will include stormwater conveyance
structures that will direct runoff to the pond. A note has been added
stipulating that all roof drains will direct runoff to the pond.
9. As noted in comment #3, the front of the duplex lots will drain toward the
street, and the rear of the lots will drain away from the street. The street will
be designed with drainage structures to carry the stormwater to the pond.
10. Correction made to SWU-101, Supplement Form and Calculations.
11. N/A
12. N/A
13. NIA
14. N/A
15. N/A
16. N/A
17. The .Routing Calculations show that the 1" storm will be drawn down
between 2 and 5 days for all storms between 1yr and 500yrs.
18. The Stage -Storage table for each storm event is included in the calculations.
19. N/A
20. N/A
21. N/A
22. N/A
23. N/A
24, The Riprap Sizing Calculations are shown as Outlet Protection #1 and Outlet
Protection #2 on plan sheet S-4a. A typical detail showing the geometry of
the riprap apron is included on details sheet D-1.
If you need additional information or have questions, please contact us at (91.9) 894-
7765 or [e-mail].
Re ctfully
Christopher Rogers, Enoch Engineers, PA
S:lprojects9554-HCC SHOPPING CENTERIdocumenws & correspondence\STORMWATER