Authors: Craig Nistor1, Scott Rees1, Laura Hazlett2, Olivia Mahony2
Conference: CDA 2025 Annual Conference and Trade Show
Date: September 29 - October 1, 2025
1 Knight Piésold, Vancouver, British Columbia, Canada
2 Klamath River Renewal Corporation, Berkeley, California, USA
ABSTRACT
The Klamath River Renewal Project (KRRP) involved the removal of four hydroelectric facilities on the Klamath River in southern Oregon and northern California, USA, to restore natural flow and volitional fish passage through the dam and reservoir reaches. This is the largest dam removal project to date in the USA. Key environmental and dam safety objectives and constraints for the dam removal works included the following: 1) reservoirs needed to be substantially drawn down (drained) during the winter season prior to dam removal; 2) reservoir drawdown rates needed to address the potential for instability of embankment dam slopes; 3) embankment dams had to be removed during the summer season when the risk of overtopping by flood flows was lowest; and 4) the final cofferdam breach at the largest, most downstream dam had to be engineered and timed to limit the peak discharge rate resulting from the release of water in the lower part of the reservoir. Dam removals were completed by October 2024, in time for the fall salmon run. Salmon were observed to have migrated upstream past the uppermost former dam site within weeks of the dam removal works being completed. Restoration and revegetation activities in the former reservoir reaches are ongoing.
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