20110165 Ver 1_Staff Comments_20110829

11-0165 US Foodservice Inc. Zebulon - take 2
AML comments
August 29, 2011
Pertaining to the large stormwater wetland:
a. Please show proposed one-foot topographic lines for the swale that is discharging from
the site to the wetland. Please show how the swale will discharge into the forebay of
this device and provide outlet protection if necessary.
b. DWQ highly recommends providing at least one more deep pool in this wetland to
encourage the growth of Gambusia fish, which are highly effective mosquito predators.
c. Please remove the plants from the micropool where the outlet structure is located to
reduce the risk of the outlet clogging.
d. Please provide a specification for the maximum permeability of the wetland liner (see
page 10-17 of the BMP Manual).
e. Please provide anti-seep specifications for the outlet barrel.
2. Pertaining to the small stormwater wetland:
a. Please show the placement of the outlet structure in the 1" = 20' detail on Sheet C
13.01.
b. Please provide a specification for the maximum permeability of the wetland liner (see
page 10-17 of the BMP Manual).
Pertaining to the wet detention pond:
a. Please show the placement of the outlet structure in the 1" = 20' detail on Sheet C
13.01.
The invert of the wet detention pond must be set at 228.00 fmsl in order to provide one
foot of sediment storage. Based on the plan view, it looks like the invert is at 229.00.
Please provide a specification for the maximum permeability of the wetland liner (see
page 10-17 of the BMP Manual).
Please harden the emergency spillway with rip-rap or concrete.
4. Pertaining to the level spreaders:
a. Please show the proposed one-foot topographic lines for the vegetative filter strip and
how they tie into existing ground.
b. Please provide greater storage capacity in the blind swale. The BMP Manual
recommends a depth of one foot and a width of six feet for the blind swale. The 24-inch
curb structure that is proposed has a much small cross-sectional area than this.
Providing adequate storage in the blind Swale is especially crucial for a LS-VFS that is
designed to handle the 10-year storm directly from the drainage area.
c. The level spreader is required to have an adequately sized footer to protect against frost
heave.
d. Please show the forebays in the LS-VFS details shown on Sheet C 13.00.
e. Please provide specifications for the topsoil, sod and watering needs of the sod that will
be used in the vegetated filter strips.
Lucas, Annette
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Amy-
Here are my comments.
Annette
Lucas, Annette
Monday, August 29, 2011 1:34 PM
Chapman, Amy
Lucas, Annette
11-0165 US Foodservice Inc. Zebulon - take 2
11-0165 US Foodservice Inc. Zebulon - take 2.docx
Annette M. Lucas, PE
Environmental Engineer
NCDENR DWQ Wetlands and Stormwater Branch
1650 Mail Service Center, Raleigh, NC 27699-1650 (tit ii i I)
512 N. Salisbury St, Raleigh, NC 27604 Stn Floor ?,I
Phone: [phone] Fax: [phone] Email: \1 i il'
Website http://portal.ncdenr.org/web/wq/swp/ws/401.
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