In 2010, dam safety climbing inspections of the Foster Dam spillway gates identified alarming structural damage to the Tainter gates. The damage was a warning sign of potential overstressing of the gate strut arms due to increased trunnion friction.
Increased trunnion friction was the culprit at a failure of the Folsom Dam spillway gates in 1995. Trunnion friction was not a mechanism well understood at the time of the original design of the dams and modern design guidance requires this to be considered. After careful analysis of the gates at Foster Dam and the others within Portland District, the need for major repairs was clear.
Rapid repairs of the Foster dam gates included strengthening the gate structure as well as improving the trunnion materials to reduce the friction. Since 2010, similar repairs have been made across the dams in the Willamette Valley. The repairs have included structural strengthening of the gates, upgrades of the mechanical components, and electrical reliability improvements. The spillway gate rehabilitation and reliability improvements have been completed at a majority of Willamette Valley dams, or are currently underway. The table below provides an updated status as of January 2020. For more information, read an article about spillway gate repairs here.
For current and projected Willamette reservoir and river elevations and flows, visit our Water Management page or the Northwest River Forecast Center.