U.S. Corps of Engineers employees clean out drains in the
Pomona Lake stilling basin as part of a five-year inspection
of the dam. Normally filled with water, the conduit that allows
flow from the dam gates was drained for access by inspection
POMONA LAKE—Most people probably don’t think
about Pomona Lake’s dam much as they drive on it or
boat by it. A dam is a dam, right? But luckily for Osage County,
which has two federal reservoirs, there are people who think
about dams and dam safety every day. And last week, there
was a lot of dam contemplating going on, as about 30 U.S.
Army Corps of Engineers’ employees gathered to conduct
a five-year inspection of Pomona Lake dam.
USACE staff conducts inspections daily, monthly and annually,
along with the five-year detailed inspection. Every 10 years,
or during every other five-year inspection, the stilling basin
below the dam is drained, or “dewatered” in government
terminology. During dewatering, the entire water release system
is inspected from the downstream basin, up the conduit, to
the hydraulically operated gates that control the flow of
water out of the lake.
In all, four specialized inspection teams, made up of engineers
and geologists, swarmed in, under, on top, along side and
through the dam last week.
A geotechnical team looked at the dirt embankment for abnormalities,
checked for seepage, and inspected the lakeside riprap.
A structural team checked the interior of the concrete conduit,
looked at the gate fixtures, and inspected the control tower,
or “anything to do with concrete,” as described
by Bob Dimmitt, a retired Corps civil engineer who assisted
with the inspection. The structural team also inspected the
lake’s emergency spillway, which would only be used
in the event the lake filled beyond its capacity.
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