Friday August 7, 2026
USGS —
It has been almost two years since the largest dam removal project in U.S. history took place at the border of Oregon and California. The Klamath dam removal, beginning in 2022 and ending in 2024, removed four hydroelectric dams from the Klamath River: J.C. Boyle Dam, Copco No. 1 Dam, Copco No. 2 Dam, and the Iron Gate Dam.
While the dam removal is complete, work to restore the 2,200 acres of formerly submerged lands continues. As the reservoirs drained, native seed mix was applied to the reservoir footprints to stabilize sediments and improve soil composition.
Additionally, these dams, built between 1918 and 1962, blocked salmon migration and altered water quality for over a century. Now, with the dams out, USGS Western Fisheries Research Center (WFRC) scientists are monitoring and analyzing the effects of dam removal on migration rates and survival of juvenile salmon in the Klamath River. These fish have been granted access to more than 400 stream miles, including cold-water tributary creeks and streams in the upper Klamath Basin important to Chinook salmon, coho salmon, and steelhead.