20200859 Ver 1_02_Supplemental_Info_20200618_20200629

Section B3d - Explain the purpose of the proposed project:
The purpose and need for the new Yadkin Regional Water Supply Pipelines (YRWSP) are to provide a
long-term water supply to Union County’s Yadkin River Basin Service Area. The project includes the
withdrawal of water from Lake Tillery, in Stanly County, for transfer to a new water treatment plant in
Union County for treatment and distribution.
Existing Infrastructure
Union County (County) has seen significant growth over the past two decades and is expected to
continue to have steady growth and development into the foreseeable future. In response to this
growth, the County has worked diligently to meet the increasing demands for public water supply and
other services. Further, the County has completed an extensive water supply planning effort, and has
identified opportunities to provide a long-term, sustainable water supply solution for its citizens and
community. The purpose and need for the YRWSP is to provide a long-term water supply to Union
County, Norwood, and surrounding areas and was fully detailed and studied in the YRWSP
Environmental Impact Statement (EIS) (HDR 2015).
Environmental Background
In 2015, Union County completed an EIS regarding the YRWSP and Interbasin Transfer (IBT) Certificate
for developing a long-term water supply for Union County. Union County obtained a Record of Decision
for this EIS on April 12, 2016 and subsequently received a Final Determination from the North Carolina
Environmental Management Commission to grant an IBT Certificate for the YRWSP on May 11, 2017.
In accordance with Duke Energy Lake Services’ Conveyance Permit Application Part V, an application for
this project was prepared for FERC review and approval to be used by FERC to grant authorization to
Duke Energy (i.e., licensee of the Yadkin-Pee Dee Project) to permit a non-project use of the project
boundary (i.e., water withdrawal from Lake Tillery).
Proposed Infrastructure
The proposed design meets the project’s purpose and need of delivering a safe, sustainable water
supply to meet current and future water demands, as well as the associated environmental impacts,
mitigation measures, technical feasibility, and financial impacts. The project consists of construction of
all the elements needed for the 42-inch and 54-inch diameter, steel raw water transmission pipelines,
water treatment plant, and 36-inch diameter, ductile iron finished water distribution pipeline.

Section B3e - Describe the overall project in detail, including the type of
equipment to be used:
The Project will consist of a raw water transmission pipeline (RWTP), a water treatment plant (WTP),
and a finished water distribution pipeline (FWDP). The RWTP will consist of approximately 24.9 miles of
42-inch pipeline that will be pumped to the Hydraulic Control Structure, at approximately STA 1314+00.
From there it will be gravity fed through a 54-inch pipeline to the water treatment plant approximately
5.1 miles away. The 36-inch FWDP will then continue from the WTP in a westerly direction to the
terminus near the intersection of N. Rocky River Road and Secrest Shortcut Rd approximately 10 miles
away.
The Project is proposed to be installed within permanent easements to be purchased by Union County
and the Town of Norwood. Temporary easements necessary for construction of the proposed pipeline
will be acquired to provide equipment staging areas, and material storage areas and access to
permanent easement areas during construction. The permanent easement width for the RWTP is 60
feet in most areas. The RTWP construction corridor width and permanent, maintained easement width
are both proposed to be larger than the easement widths recommended by the North Carolina Division
of Water Resources (NCDWR). The construction corridor width is proposed to be larger because of the
size of pipe and associated excavation, the need for temporary stream crossings and the size of
equipment required for pipe installation. The RWTP permanent easement width is proposed to be larger
because a second, parallel raw water pipeline is expected to be required in the future to meet projected
future water demands. Acquisition of the larger RWTP 60-foot permanent easements allows the burden
of the complex, lengthy and expensive real estate process to be reduced for Union County, the Town of
Norwood, and property owners. The permanent easement for the FWDP is 25 feet wide with a
temporary construction easement width of 15 feet.
Installation of the Project will require temporary and permanent impacts to streams, wetlands and open
waters. Temporary impacts are associated with temporary construction access and installation of the
raw water pipeline and associated infrastructure such as blow-off valves and relief valves. Permanent
impacts to open waters are associated with moving the existing dam to a location outside the
permanent easement and filling to create uplands within open water OW 1C.
All stream and wetland crossings are proposed to be constructed using open-cut installation methods.
Open cut installation methods are proposed because the large diameter of pipe which limits the use of
trenchless technologies (e.g., horizontal directional drilling) to smaller pipes or longer installations. The
use of open-cut installation methods also reduces the risk of damage to surface waters associated with
the release of drilling fluid used in horizontal directional drilling. Where the proposed raw water pipeline
is installed within roadway embankments, a jack-and-bore auger machine will be used to install a steel
casing and raw water pipeline within the embankment.
Dewatering to install the Project below the streambed will allow the contractor to work in dry
conditions and minimize downstream sedimentation. Temporary vehicle stream crossings will utilize the
design noted in Detail C-35-0704/D3. The use of a temporary impervious dike and bypass pumping
system shall be employed for smaller streams and a temporary impervious coffer dam flow diversion
system shall be employed for larger streams. Excavated material will be temporarily stockpiled adjacent
to the dewatered construction area and be replaced following pipe installation. Dewatering of streams
using an impervious dike and bypass pumping system shall last no longer than 24 hours. Dewatering
systems will be completely removed, and pre-construction contours will be restored, as soon as possible
after pipe installation is complete.
Streams impacted by temporary construction activities will be restored to pre-construction contours as
soon as possible after construction activity in each stream is complete. Stream banks that are disturbed
as part of the proposed pipelines installation will be stabilized with erosion control matting, straw
mulch, temporary cover seed, and a permanent native seed mix. Erosion control matting that includes
plastic twine or mesh shall not be used on stream banks. Live stakes shall be used within temporary
construction easements and within permanent easements where they can be installed at least 20 feet
away from the proposed pipe centerline.
Wetlands impacted by temporary construction activities will be restored to pre-construction contours as
soon as possible after construction activity in each wetland is complete. During excavation, topsoil will
be removed separately and re-deposited on top of backfill material. Anti-seep collars will be installed
downstream of wetland crossings and every 150 feet up the gradient until the pipe exits the wetland. A
temporary cover seed mix and a native wetland seed mix will be applied to all wetland areas impacted
during construction. Straw mulch will be applied over seed mixes to temporarily control erosion and
provide conditions conducive to seed establishment.
Temporary erosion and sediment control measures shall be installed to reduce sediment loss from
disturbed areas. Temporary measures proposed for this site include silt fence, tree protection fence,
stabilized construction entrances/exits, erosion control matting, inlet and outlet protection measures,
fiber filtration tubes, temporary stream crossings and temporary seeding. Temporary and permanent
vegetative cover for disturbed areas will consist of a native seed mix and temporary cover species as
recommended by North Carolina Department of Environmental Quality (NCDEQ) Land Quality and the
Natural Resources Conservation Service. Erosion control measures, including temporary stream
crossings, shall be removed once the site is stable and construction access is no longer needed.
Construction equipment anticipated to be used includes wheeled backhoes and loaders, tracked
excavators, bulldozers, dump trucks, flatbed trucks, compaction equipment, skid steer loaders,
dewatering pumps, hand tools and jack-and-bore auger machine.

Section B6b – Phased Project
The RWTP is a phased portion of the Project to meet future projected water supply demands. A 36-inch
pipeline will be installed parallel to the approximate 24.9 miles of 42-inch pipeline. This 36-inch pipeline
will be installed from the pump station on Lake Tillery to the hydraulic control structure at STA 1314+00.
Based on future water demand projections the additional 36-inch pipeline will be able to supply the
WTP with the additional raw water to meet the future demand. This in turn is the reason for the 60-foot
wide maintained RWTP easement from Lake Tillery to STA 1314+00.