Dworshak Leaks Won’t Be Plugged Floods Put Repair Project On Hold Until Next Fall

The leaking Dworshak dam won’t be fixed until next fall at the earliest, the U.S. Army Corps of Engineers said Friday.

The estimated $3 million project was started last November, but was interrupted by floods that raised the level of the reservoir 40 feet, said dam safety chief Everett Wright.

“The water caught us,” Wright said. “Mother Nature decided last winter wasn’t the time to fix it.”

Now, the amount of water leaking from the dam varies from an estimated 2,500 gallons a minute to 1,200 gallons a minute. The water is leaking from cracks in the bedrock where the concrete structure meets the rock.

The continual leakage is causing the fissures to erode and grow larger, Wright said.

“We’re dealing with water physically moving in the bedrock at a pretty high velocity,” he said.

But while the cracks continue to grow, Wright said the problem does not pose an immediate risk to the structural integrity of the dam or to downstream residents.

“We want to make sure this problem doesn’t ever get anywhere near that condition, and it’s certainly not near that now,” Wright said.

The Dworshak dam is just upstream from Ahsahka, a small town on the north fork of the Clearwater River. The dam, built in 1972, created a 53-mile slack-water reservoir.

Last fall, the Corps of Engineers hired Christian Boyles Corp. of Salt Lake City to grout the cracks. The work involved drilling holes into the bedrock near the fissures and filling them with cement.

The work had just begun when the rapid increase of water in the reservoir forced them to stop. On Nov. 30, 1995, the average water flow into the reservoir was recorded at 60,000 cubic feet per second, the second highest flow since 1927.

This summer, the corps studied the seepage and the pressure against the dam, so that a safe grouting procedure can be designed for different water levels, said spokesman Dutch Meier.

The initial repair contract was for $1.3 million, but the amount the contractor will get for the unfinished work is unresolved. The revised estimate is for almost $3 million to finish the job, Meier said.

, DataTimes MEMO: This sidebar appeared with the story: LEAKY HISTORY It’s not the first leak at the dam. Soon after it was built, it sprung a leak from a 50-foot crack.