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Embankment work at Priest Rapids Dam to cost $13 million less than estimated

The low bid to build a secondary embankment on the Yakima County side of Priest Rapids Dam came in at $33.4 million, almost $13 million less than the engineer’s estimate, reports Managing Director of Power Production Ty Ehrman.

The low bidder was IMCO Construction of Ferndale, Wash. Commissioners are expected to vote on awarding the bid at their Jan. 28 meeting.

Work is expected to begin by early March 2020 and be finished by May 2023. The Priest Rapids right-bank project is a federal requirement to improve the dam’s seismic resistance. Priest Rapids Dam is 10,103 feet long and was completed in July 1956. It impounds water for a powerhouse with a capacity of 955.6 MW.

In other news, Ehrman reported on unit availability in 2019 at the Priest Rapids and Wanapum projects. Availability was far below target last year, he said, due mainly to unexpected unit outages at Priest Rapids Dam.

The aged units are undergoing a 10-year rehabilitation process. Unexpected outages happened at five of the 10 turbine-generator units last year, including a fire in each of two of the units’ exciter cabinets. Ehrman attributed the fires to inadequate record-keeping that resulted in a lack of needed maintenance to the two units.

“It’s safe to say we had a rough year,” Ehrman told commissioners. On the fires, he added, “This is a very good example of the need to be clear and crisp in documenting our maintenance program.”