Scores turn out to see progress at dam

A tour of work at Lower Monumental Dam drew about 140 people to the remote site Wednesday afternoon.

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Tour participants look over the edge of Lower Monumental Dam's cavernous navigation lock during a tour Wednesday. It was a rare opportunity to see the structure almost completely empty of water. (Jan. 26, 2011)

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What does it take to lift sections of a 700-ton lock gate? How about 1,650 tons of counterweights? That's the weight of the concrete blocks on the back end of the huge crane being used on the job at Lower Monumental Dam. (Jan. 26, 2011)

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Lower Monumental Dam's new downstream lock gate. The three sections of the structure were fabricated in Vancouver, then floated up the Columbia and Snake Rivers on a barge. When assembled, the new gate weighs about 700 tons and is 88 feet wide, 84 feet high and 15 feet thick. (Jan. 26, 2011)

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Construction workers, such as the one walking across the top of the photo, are dwarfed by the scale of work to repair a section of the concrete wall in the navigation lock at Lower Monumental Dam. (Jan. 26, 2011)

KAHLOTUS, Wash. -- A big job drew a big crowd of sightseers Wednesday.

Despite the remote location, about 140 people made their way to Lower Monumental Dam in northern Walla Walla County to see progress on major repairs to the massive structure.

Organized by the U.S. Army Corps of Engineers, which operates the dam, visitors were allowed to walk along the top of the dam's navigation lock and peer down into its depths where workers are replacing the downstream gate, repairing a section of the interior wall and doing other maintenance work.

"My husband and I just thought we would come out and see what this looks like," said Michele Criss, who with her husband, Steve, had driven from Walla Walla for the tour. "It's pretty fun and it's a nice day."

After donning Corps-issued hardhats, tour participants broke into groups and went to different locations along the lock wall where Corps engineers talked about the challenges of replacing the 700-ton downstream lock gate and repairing a 130-foot tall section of the lock wall where the concrete had deteriorated.

"This part is called 'monolith 15'" said Steve Thompson, the project manager for the Corps. "Even back in the 1990s it was spalling and in the early 2000s we started seeing cracking." After investigation, the repairs were planned and last year the Corps was able to obtain funds to start the first part of the three-phase project.

That entailed breaking out enough concrete to fill about 150 dumptrucks, Thomas said. Workers are now preparing to replace enough of the concrete wall to allow the lock to re-enter service this spring with the remaining concrete replacement to be done at a later date.

As that work proceeds, workers are aligning and welding the parts of the new lock gate. The last section of the 700-ton structure was installed Tuesday, lifted into place by the towering Lampson Transi-Lift LTL crane that was erected next to the lock late last year.

The new gate will replace the original, which went into service in 1969 and was cycled through thousands of lockages before time, wear and tear took its toll, necessitating its replacement. The need to replace the gate, along with two other lock gates at The Dalles and John Day dams on the Columbia River, as well as other repair work plus routine maintenance, led to an unprecedented shutdown of the entire Columbia-Snake river transportation system.

When the work will be completed was one of the questions fielded by Andrew Rajala, project engineer, from visitors during Wednesday's tour. As his answer indicated, contractors are facing a fairly rigid deadline to get the work done.

"The completion date is pretty much midnight on March 12," he answered.

Andy Porter can be reached at andyporter@wwub.com or 526-8318. Check out his blog at blogs.ublabs.org/randomthoughts.

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