20150615 Ver 1_160624 CRL to Cory Larsen at NCDEQ_20160624

TM
BOHLER
ENGINEERING NC. PLLC
NCDEQ
Archdale Building
1617 Mail Service Center
Raleigh, NC 27699
Attn: Cory Larsen, P.E.
Dear Mr. Larsen:
4011 WestChase Boulevard, Suite 290
Raleigh, NC 27607
PHONE [phone]
Date: June 24, 2016
Via Hand Delivery
Re: Lidl Grocery Store
705 U.S. 74 Business
Rockingham, NC 28379
Richmond County
BE # NCR151000
Bohler Engineering is pleased to submit on behalf of Lidl US Operation, LLC. the revised plans for the
Lidl Grocery store in Rockingham, NC located at 705 U.S. 74 Business. The following is our comment
response letter addressing comments received from Belinda S. Henson dated May 13, 2016. Each
comment is addressed and responded to as follows:
NCDENR, Division of Water Resource, Belinda S. Henson:
Comment 1: Please provide a completed copy of the Wet Detention Basin Supplement Form including
the required items Checklist with initials and indication of Plan Sheet for each item.
Response 1: The Wet Detention Basin Supplement Form has been included for your review.
Comment 2: Revise plans as necessary to include all items on the Required Items Checklist on the
Supplement Form (e.g grading and drainage plan with delineated drainage basins with
Ration C coefficient per basin, vegetated shelf planting plan, etc).
Response 2: All required items have been provided for the Checklist on the Supplement Form.
Comment 3: The proposed roof drains do not appear to convey flow into the stormwater collection
system but rather to a depression that drains to a roadside ditch. Please ensure that runoff
from all impervious areas is conveyed to the proposed wet detention basin.
Response 3: Proposed roof drains have been modified to convey stormwater runoff into a
bioretention located directly behind the building. See plan set for additional details.
Comment 4: Revise the wet detention basin cross section to specify side slopes of 3:1 or less.
Response 4: Slopes within the wet detention basin are 3:1. Slopes within the forebay are 2:1 per
our discussion with Cory Larsen on 6/21/16.
CIVIL AND CONSULTING ENGINEERS • PROJECT MANAGERS • SURVEYORS • ENVIRONMENTAL CONSULTANTS • LANDSCAPE ARCHITECTS
WWW.BOHLERENGINEERING.COM

BO1 1 L E 1� Cory Larsen
Rockingham Grocery Comment Response
ENGINSSIIING NC, PLLC June 24, 2016
Page 2 of 2
Comment 5: Revise the orifice diameter shown on both the riser structure detail and water quality
detail to be consistent with design calculation (1" instead of 4" and 1.25", respectively).
Response 5: The orifice diameter has been updated to stay consistent with our design
calculations.
Comment 6: Please provide calculation on the outlet velocity from the wet detention basin outfall prior
to discharge to adjacent wetlands. Note that a non-erosive velocity of two feet per second
or less must be achieved for the peak flow from the 10 year storm.
Response 6: Outlet velocity from the detention basing during the 10 year storm event is 1.34 ft/s.
See stormwater calculations for more details.
Should you have any questions regarding this project or require additional information, please do not
hesitate to contact me at [phone].
Sincerely,
Mike Roselli, P.E.
Bohler Engineering NC, PLLC
CIVIL AND CONSULTING ENGINEERS • PROJECT MANAGERS • SURVEYORS • ENVIRONMENTAL CONSULTANTS • LANDSCAPE ARCHITECTS
WWW.BOHLERENGINEERING.COM