To minimize disruption of the Columbia-Snake River navigation system, the gate replacement at the Dalles Dam Navigation Lock was completed in the depths of an Oregon winter. On Dec. 8, the day the new gate arrived on site, 8 in. of snow fell.

By January, the project had accrued more than 20 inclement weather days that, for the most part, were worked through when the work could be done safely. To remove the existing lock gate, crews cut the gate into three sections and demolished sections of the lock’s concrete walls. Workers also replaced the hoist machinery that raised and lowered the upstream gate. The arms supporting the downstream gate leaves, each weighing 500 tons, were also replaced. All the electrical wiring and controls were replaced and upgraded throughout the entire lock.

Related Article: Top Projects Reflect Innovation, Creativity