Page 15 - 2020 January E-issue

Many of these items were also required for permit application to the
United State Army Corps of Engineers (USACE) for construction. This
process began in January of 2019 and was complete, with all permits
obtained 6 months later.

Before any construction could begin, BVR Construction was required
to present a design and plan to install a temporary cofferdam system to
isolate the work area from the Genesee River and protect the workers
within that area. LaBella’s Steve Gauthier (Sr. Structural Engineer)
worked with BVR Construction to design a steel cofferdam system that
would protect the workers from 4 feet of river. Crane placement plans
and rigging plans were created to detail how this system would be
installed and function. A similar cofferdam was designed for installation
in the lower tailrace section to establish an isolated work area there as
well.
The cofferdam allowed consistently safe access to the riverbed and Aerial view of the work-site prior to construction.
tailrace. A crane placed on the edge of the river allowed equipment
and material to be lowered into the work area and 170 feet of existing
concrete wall was removed. To ensure a solid foundation, surface rock
was removed to a depth of 2 feet and the new wall would be anchored
by steel dowels embedded 4 feet into the bedrock. In total, 8 tons of
reinforcing steel and 175 cubic yards of concrete would make up the
new diversion wall.

In parallel, a 3 foot diameter boring through 5 feet of existing concrete
and steel was completed to provide access to the plant from behind the
isolation gates. Above this boring will be a concrete vault topped with
a manhole cover. This structure will allow safe access at times of high
water when a lower access point would be submerged. The isolation
gates, designed by LaBella in 2015, required modification to meet
the new purpose and mate with the gantry system. BVR Construction
worked with local contractors to complete this work and ensure that all
modifications met LaBella’s design and specification. Cofferdams in place to protect workers.

Once complete, LaBella will conduct inspections of the stop log gates,
gantry system, and access platform before Station 26 will be restored
to service. The new diversion wall will allow the plant to operate closer
to full generation capacity by keeping separate the Genesee River and
the Station 26 tailrace. In the future, RG&E Operators will have the
ability to raise and lower the plant isolation gates as needed to safely
access the inner workings of the unit for maintenance activities and
inspection.
Using the Genesee River as a powerful source of energy is a
Rochester tradition that earned it the nickname of ‘The Flour City’.
Look for Station 26 to be back on line and generating renewable
energy in February 2020. The upgrades to the facility will allow the
unit to generate 3MW more often. The power supplied equates to
approximately 2,400 homes. q
LaBella engineers inspect the plant discharge structure.

Author Bio:
Donald Lucas: Don is a Project Manager within LaBella’s Hydropower Division. He has over seven years of experience in nuclear power generation, energy
distribution, electrical and control system design, construction, testing and servicing. He has skills in radio and cellular communication system configuration,
HVAC design, and commissioning.

cover article JANUARY 2020 The ROCHESTER ENGINEER | 15