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Economic and dam related articles

Bonneville Lock Damaged,
Corps Extends Columbia-Snake Closure

by Staff
East Oregonian, March 19, 2011

(Andy Porter) 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. PORTLAND -- "The U.S. Army Corps of Engineers" in the Portland and Walla Walla districts alerted commercial and recreational mariners Friday that it is extending the closure of the Columbia-Snake rivers navigation lock system because of unforeseen delays.

The agency also reported an accident Thursday damage an upstream lock gate at Bonneville Dam, delaying its reopening.

Scott Clemans, a Corps spokesman, said work on Lower Monumental Dam's downstream lock gate replacement experienced a problem because of recent high winds and rain. That resulted in additional time needed to complete the work. Walla Walla District officials adjusted the lock's reopening date to 5 p.m. March 26.

The recent weather at the dam kept the new metal surfaces wet, affecting conditions for sandblasting and painting the new gate and completing fit-up, welding and installation of the seal-framing assemblies, Clemans said. The gate cannot be placed under a cover to keep it dry because of its size and the need to move the gate frequently during painting and welding to access the bare-metal end plates.

"The final steps in finishing the gate involve precision work, which must be done individually in a prescribed sequence, so the new gate's seals will align properly with the existing lock structure," he said.

At the John Day lock, workers are making final adjustments to the new navigation lock gate components. Engineers anticipate the lock will open to river traffic at 11:59 p.m. Sunday.

The Dalles navigation lock is being tested to ensure a proper fit to the new navigation lock gates. If tests scheduled for Tuesday reveal the gates are not fitting together properly, additional adjustments may be needed, which would require dewatering the lock to access the lower portion of the gates.

"At this time, engineers anticipate that the navigation lock will open as planned at 11:59 p.m. on March 23," Clemans said. "However, if the additional time is required, work would delay The Dalles opening until 11:59 p.m. on March 25."

Meanwhile, operation of the Bonneville navigation lock has been significantly curtailed because of damage to the upstream gate Thursday. The lock was scheduled to reopen at 11:59 p.m. Friday.

The Corps is coordinating with commercial barge lines to accommodate critical lockage needs during the next few days using alternate upstream barriers; lockage times are likely to be three to six times longer than usual, Clemans said.

The gate was damaged during a routine operation to flush debris out of the upstream channel and through the lock. The top of the gate was exposed to high water pressure and buckled when drain valves pulling water into the lock failed to fully close.

Corps employees are investigating the cause and extent of the damage to the gate. The nature and duration of needed repairs is not known. The Corps expects to issue an update Monday.

Four other locks in the Walla Walla District are in service, providing passage for commercial shippers and recreational boaters. Lower Granite, near Pomeroy, Wash.; Little Goose, near Starbuck, Wash.; Ice Harbor, near Burbank, Wash.; and McNary, near Umatilla, took advantage of the available time without river traffic to accomplish additional lock work that ordinarily would exceed the annual two-week winter maintenance outage. Outage periods for those locks ranged from five to nine weeks with various closing and reopening dates.

Related Pages:
Extended Navigation Lock Outage US Army Corps of Engineers

Bonneville Lock Damaged, Corps Extends Columbia-Snake Closure
East Oregonian, March 19, 2011

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