Drilling Crews Search For More Leaks At Priest Rapids Dam

Workers drill core samples in the grout galleries of Priest Rapids Dam in southeast Washington to figure out how extensive leaking is in the structure’s spillway. CREDIT: GRANT PUBLIC UTILITY DISTRICT
Workers drill core samples in the grout galleries of Priest Rapids Dam in southeast Washington to figure out how extensive leaking is in the structure’s spillway. CREDIT: GRANT PUBLIC UTILITY DISTRICT

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Crews are drilling deep into southeast Washington’s Priest Rapids Dam on the Columbia River to find out the extent of damage after leaks were recently discovered. 

So far, crews have drilled about 80 core samples in the dam’s spillway structure, and they plan to drill more than 200 altogether over the next couple months.

Two of the holes are leaking three to four gallons of water per minute, according to Grant Public Utility District officials.

That leak has been traced to a lift joint, which is a seam between two pours of concrete located near the bottom of the dam.

To lessen the pressure until they know more, operators have lowered the pool behind the dam about three feet below what would be normal for this time of year. That might become tricky when spring melt comes. But dam operators said the structure is still safe.

The exploratory drilling costs about $30,000 a day.

Behind the dam lies Priest Rapids Lake, which is about 80 feet deep and stretches 18 miles up the Columbia River. Priest Rapids is the last dam upriver from the Hanford nuclear cleanup site.

Copyright 2018 Northwest News Network

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The president just unraveled years of work on tribal rights, salmon and clean energy. So what happens next?

Less than two years ago, the administration of President Joe Biden announced what tribal leaders hailed as an unprecedented commitment to the Native tribes whose ways of life had been devastated by federal dam-building along the Columbia River in the Pacific Northwest.

The deal, which took two years to negotiate, halted decades of lawsuits over the harm federal dams had caused to the salmon that had sustained those tribes culturally and economically for thousands of years. To enable the removal of four hydroelectric dams considered especially harmful to salmon, the government promised to invest billions of dollars in alternative energy sources to be created by the tribes.

This story comes to you from Oregon Public Broadcasting and the Northwest News Network, a collaboration between public media organizations in Oregon and Washington.

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