Chittenden Locks large chamber closes to vessel traffic October 7-9

Published Oct. 3, 2014

SEATTLE – The Hiram M. Chittenden Locks large chamber will close to vessel traffic from 7 a.m., Oct. 7 to 7 p.m., Oct.  9.

U.S. Army Corps of Engineers officials are test drilling for an upgrade of the large lock’s emergency closure system. The Small Lock will continue operations.

The aging emergency closure system was identified as one of 12 potential issues when the Lake Washington Ship Canal, which includes the locks and Montlake and Fremont Cuts, received a revised dam safety action classification in 2011.

A risk-based tool, the Corps uses the classification system nationwide to prioritize dam safety decisions and allocate funding. Experts try to plan for every possible scenario that could take place, analyze the potential risks and come up with solutions long before they become reality.

Upon receiving the revised classification, the district created a fiscally-responsible, workable effort that addressed the potential issues, according to Seattle District Chief of Operations JoAnn Walls. The plan, not publicly releasable for security reasons, addressed each issue with interim risk reduction measures.

Upgrade of the emergency closure system is the latest project as part of the Seattle District’s plan to keep the Locks safe and functioning for years to come. Recent replacement of the spillway gates, soil water pressure testing around the site, a scour repair in 2012 and development of a plan in case of a tsunami have all been completed.

“The dam safety program is critical to addressing the nation’s aging infrastructure and ensuring dams are safe and present minimal public risk,” said Walls. “We’ve completed repairs and studies that address several primary concerns and are aggressively working our long-term solutions along with prioritizing other aging systems at the facility.”

Bill Dowell

Release no. 14-043