Generator—Summer 2022

UNDERWATER
INSPECTION
The Columbus and Monroe powerhouses
are impressive structures.
But they are more than 80 years old and
need regular tending. The employees who
work there every day spot mechanical and
structural issues on the inside and outside.
But what about under?
That’s where things get a little more
tricky.
There are trash rack supports under the
water on the upstream side of the Monroe
Powerhouse (MPH). These racks prevent
debris from entering the generator turbines
and regulating wicket gates.
Last year, employees noticed
that the wear plates that protect
these supports were deteriorating and
needed maintenance.
Accessing underwater areas of the
canal is no easy task, however. That’s why
the MPH trash racks and supports had not
been inspected in almost 20 years.
In May, Loup employees completed
the task with the assistance of a diver and
crane team.
The project was scheduled for that time
because Loup could lower the upstream
water level without affecting canal irrigators.
After clearing the
debris, the location
was dewatered using
bulkheads (stop logs) to
seal off the canal.
Each of the two generator
intakes is divided into
two sections. Each
requires three stop logs
stacked on top of each
other to provide a safe
barrier between the canal
and the work area.
Once the stop logs were installed and
each section was dewatered (above),
the trash rack sections were removed
(left) with the help of a crane. The racks
were tagged, cleaned, and inspected.
Top: Kenny Ferris with Husker Marine of Burwell prepares to check for debris at the powerhouse.
Above left: Lance Ferris, Canal Lead, and Brad Morton, Hydro Superintendent, monitor the dive
from the powerhouse deck.
Above middle: Lance Ferris (right) helps Kenny Ferris replace his oxygen tank.
Right: A log is removed from the bottom of the canal after being discovered by the diver.
Photos by Brad Morton, Lance Ferris, and Stacy Wemhoff.
After the racks are removed, the support structure
is inspected (right) and repaired as needed (above).
Then the racks are reinstalled, the stop logs are
removed to allow water back into the scroll case,
and the generator is placed back into service.
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