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Emergency Bonneville Navigation Lock Outage
Submitting Company: Advanced American Construction

Location: Cascade Locks
Cost: $1,953,371
Start Date: September 2019
Completion Date: September 2019
Owner/Developer: U.S. Army Corps of Engineers, Portland District
General Contractor: Advanced American Construction
Subcontractors: Hood River Sand, Gravel & Ready-Mix, Staton, Whitaker/Ellis

On Sept. 5, 2019, the Bonneville Dam experienced problems with the miter gate operations and equalizing the locks while a vessel was trying to head upriver. The following day, a leak was detected coming from the downstream miter gate sill.

This prompted the U.S. Army Corps of Engineers (USACE) to close the locks until a repair was complete. News reports noted that more than 100,000 tons of exports would be stranded upriver during the repairs.

USACE called Advanced American Construction (AAC) to mobilize the following day to set the downstream stoplogs so the locks could be dewatered. AAC mobilized a crane barge within hours of the phone call and quickly installed the stoplogs.

Dewatering efforts took place throughout the night and an inspection took place the following morning. It was determined that the downstream sill heaved up to a couple of inches in spots and was allowing water through the bottom of the sill. All parties acted quickly to determine a repair solution, which was full demolition of the existing sill and replacing it with a more robust anchoring scheme.

The project was ultimately completed three days ahead of schedule and the locks were reopened for business on Sept. 27.