Klamath River Renewal Project

Klamath Falls, Oregon, and Hornbrook, California

The Klamath River Renewal Project, the largest dam removal and river restoration project in US history, involved the removal of four hydroelectric dams along the Klamath River in Oregon and California to restore volitional fish passage to historic habitat and spawning grounds. Knight Piésold served as the lead designer for the prime contractor Kiewit, developing innovative designs for the safe decommissioning of the dams. As a result, over 400 stream-miles of salmon habitat have been reconnected. Within weeks of the dam removals, adult chinook salmon were observed returning to their ancient spawning grounds for the first time in over 100 years.

A landmark in ecological restoration, this project stood out for its unprecedented scale and the rapid return of salmon just months after completion. The authentic engagement with tribal nations, adaptability in the face of incomplete data, and deep integration with the surrounding ecosystem made it a model of ingenuity, collaboration, and environmental impact.