The Army Corps of Engineers plans to close navigation locks needed for boats to travel up and down the Columbia and Snake Rivers for 14 weeks.
But is is giving commercial shippers and their customers more than a year to plan for the navigation lock outage that will start Dec. 12, 2016.
The outage will allow repairs needed for the safe and reliable passage through the Columbia-Snake River navigation system, the Corps said Wednesday.
Aging infrastructure sometimes requires extensive repairs and rehabilitation that cannot be completed within the traditional two week-long annual routine maintenance outage, according to the Corps. Extended lock closures are unusual, but are coordinated across the region to reduce the impact to shippers and other users.
“The alternative to these planned, coordinated outages is unplanned emergency outages that might shut down the navigation locks for a year or more,” said Jeanette Wilson of the Army Corps. “We understand the impact this outage has on our navigation stakeholders, and will do our utmost to complete the needed work on schedule.”
Repairs will be done at these dams:
• The Dalles Dam, where the upstream gate and critical portions of the navigation lock controls require replacement. The downstream gate was replaced during the fiscal 2011 extended lock outage. The gudgeon anchors will be replaced during the coming outage.
• Ice Harbor Dam, where a high priority is new operating machinery for the downstream gate. Critical components of the machinery require complete replacement during the extended closure.
• Lower Monumental Dam, where a new downstream lock gate was installed in fiscal 2011. The second phase of the installation is the replacement of the mechanical gear that operates the gate. The newly installed downstream gate is heavier than the original, and the existing gears have reached the end of their service life.
• Little Goose Lock and Dam, where the downstream gate land-side gudgeon was replaced in April 2014. Additional work is needed during the upcoming closure to fully complete replacement of all downstream gudgeon arms and pintles. Structural items are also in need of repair, as the hinges on which the gate rests have fractured welds.