The U.S. Army Corps of Engineers announced today that it will close The Dalles navigation lock on Tuesday, May 24 at 6 a.m. to repair a gearbox that operates the mechanism for opening and closing the north leaf of the downstream gate. The lock is expected to reopen Saturday, May 28 at 6 a.m.
The closure will effectively shut down the Columbia-Snake navigation system. That means that the Corps will not be collecting and barging migrating juvenile salmon during those four days. The juvenile fish will be allowed to swim toward the ocean in-river, passing the dams via spill, mechanical passage systems and the turbines.
“We have decided to not barge from, say, Lower Granite down to The Dalles” during the outage, the Corps Bruce Henrikson said.
Each spring and summer a portion of the juvenile salmon and steelhead are collected at Lower Granite, Little Goose, Lower Monumental dams on the lower Snake and McNary on the Columbia and barged downstream for release below Bonneville, the lowermost hydro project in the system. The idea is to whisk them past predators and unfriendly conditions in the reservoirs and at the dams. Fish from above Lower Granite must pass eight dams.
The Corps warns that it will not have a complete picture of the damage and needed repairs until the gearbox is opened and drained and a full assessment performed. The Corps expects to have this information on the morning of Wednesday, May 25, and may announce an extension of the outage at that time to accommodate additional repairs.
The Corps believes that one or more bearings in the gearbox are failing. Bearing failure -- which could occur without warning -- could lead to more significant damage to other gate components and an unplanned, extended repair outage.
This interim repair should allow the gearbox to function until the next regularly-scheduled maintenance outage in March 2012, when the Corps plans to replace it.
For more information about the Columbia-Snake navigation system, visit