20181146 Ver 1_NCDEQ Response to Comments_20190109

M
A S S
January 9, 2019
cGill
0 C I A T E S
Mr. Zan Price, P.E.
Assistant Regional Supervisor — Asheville Regional Office
Water Quality Regional Operations Section
NCDEQ — Division of Water Resources
2090 US Highway 70
Swannanoa, North Carolina 28778
RE: North Fork Waterline Project
DWR#20181446
Buncombe County, North Carolina
Dear Mr. Price:
This letter is a response to your comments we received on 1/8/2018 concerning the referenced
project PCN application. Please see our comments below:
The project is required to provide an alternate water supply feed from the City of Asheville North
Fork Water Treatment Plant (WTP) into the distribution system. The North Fork WTP is the
city's largest facility at a capacity of 32 MGD and provides 70% - 75% of the water supply to the
customer base. Water is conveyed to the distribution system by two large distribution lines (24"
and 36" diameter) each of which are located within the right -of way of North Fork Left Fork
Road. The section of the roadway upstream of the point where the road crosses over the
Swannanoa River is essentially a causeway built into the old stream floodplain path with low
areas on each side of the roadway and is subject to overtopping. A major flood event in 2004
resulted in the causeway being overtopped and a section of the roadway/causeway being washed
away. This resulted in the breakage of the two large water transmission lines, disrupting service
to the City for a number of days before the road could be rebuilt and the water lines repaired. This
had a negative impact to the water system and the ability of the city to meet the demands of the
customers and provide clean potable water needed to protect public health.
The proposed project will reduce this vulnerability to the water system by providing an alternate
feed into the distribution system which is less subject to flood damage. Installing a new water line
along the toe of slope on the western side of North Fork Left Fork Road would not reduce
vulnerability as a portion of a new water line installed there would remain in the area that was
overtopped and washed away. In addition, there is a large section (approx. 1,2001f) of forested
wetland/open water that runs along the toe of slope on that side of the road which would most
likely need to be impacted during construction. These wetland and open water impacts may
exceed the proposed impacts. Alternatives were explored including armoring the
roadway/causeway to reduce impacts from flooding but would result in more wetland impacts
and new water line vulnerability than the proposed project.
1013 STATE FARM ROAD, BOONE, NORTH CAROLINA 28607 1 828.386.1920 1 www.mcgillengineers.com

Mr. Zan Price
NCDEQ — Div of Water Resources
2 of 2
Please include McGill Associates on the copy list of all correspondence for this project. If you have any
questions regarding this information, or need additional information, please contact me at 828-386-1920.
Sincerely,
MCGILL ASSOCIATES, P.A.
JV-
JON
SWAIM
Environmental Specialist II
I:\Projects\2017\Environmental\17.00346 - COA - North Fork
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