Page 17 - 2020 February E-issue

Engineering Improvements

to RG&Es Station 26

Part 2

The Station 26 hydropower floodway during a 1% annual
facility was constructed in chance flood.
1952 and is located on Court
Street in Rochester, NY. The Upon agency approval,
station utilizes a Kaplan style Bergmann designed the
turbine generator to produce demolition, reinforcement,
3 megawatts of energy from and concrete details of the
the Genesee River. Part 1 of tailrace wall. The first 170 feet
the Station 26 Hydropower of the wall closest to the plant
Station project was featured as was removed and replaced
the cover story in the January completely, with localized
e-issue of the Rochester concrete patching made to the
Engineer. The story focused remaining 130 feet up to the
on the overall purpose, project Court Street crossing. The new
management, and construction concrete is keyed two feet into the
methods implemented. This story, existing riverbed rock with shear pins
Part 2, focuses on the design protruding another 4 feet below the
development and engineering plans keyed footing. The entire wall was
for the tailrace diversion wall, a draft completed in three relatively large
tube access hatch, and the gantry pours to minimize construction joints
hoist system for two tailrace isolation and water stops to avoid deterioration
gates. in a harsh environment.

The purpose of the tailrace diversion LaBella designed a new gantry system
wall is to deflect river water away from to support new mechanized hoists
the tailrace, which conveys water and steel isolation gates. Each
from the draft tube after it has gone steel gate is 16 feet tall and 14 feet
through the turbine. With the tailwater wide and weighs 13,000 pounds.
elevation lower than the river bed, The hoist system can fully open or
there is more water head differential close the gates in 4 ½ minutes. The
between the intake and the tailrace. improvements will also include new
This creates less back pressure on platform framing, grating, handrails,
the turbine allowing it to operate more ladders, new concrete deck, and safe
efficiently due to the increase in flow. The new tailrace draft tube access. New mechanical, electrical, lighting,
wall was designed by Bergmann, who recommended and control upgrades were also part of the design to
raising the height 1 foot to reduce the likelihood of allow for a completely operational system.
overtopping while not increasing the water surface
elevation in the Genesee River during a flood event, as The LaBella project manager was responsible
required by FEMA. to coordinate technical details amongst several
engineering firms to create a positive, professional,
A team of engineers from Bergmann, HDR, and LaBella and productive team. LaBella, Bergmann, and HDR,
collaborated to obtain the permits from local, state, and along with the construction contractor, subcontractors,
federal agencies to conduct the work. A Floodplain and owner, have benefitted from a collaborative
Development Permit was required, so Bergmann group dynamic resulting in the successful Station 26
completed a hydraulic analysis of the river (FEMA no Hydropower project for Rochester Gas and Electric.
rise Report) that determined the project would not cause
any rise to the published FEMA base flood elevations Authors:
within the floodway. Although raising the wall more than Caroline Wheadon, PMP – Hydropower Discipline Leader, LaBella
one foot would benefit the generation efficiency, it would James Guistina, PE – Senior Project Manager, Bergmann
have resulted in an unpermitted incremental rise in the Donald Lucas, PMP – Project Manager, LaBella
cover article part 2 (from January issue) FEBRUARY 2020 The ROCHESTER ENGINEER | 17