HORNBROOK >> For the first time in more than a century, salmon are swimming freely along the Klamath River and its tributaries — a major watershed near the California-Oregon border — just days after the largest dam removal project in U.S. history was completed.

Researchers determined that Chinook salmon began migrating Oct. 3 into previously inaccessible habitat above the site of the former Iron Gate dam, one of four towering dams demolished as part of a national movement to let rivers return to their natural flow and to restore ecosystems for fish and other wildlife.

“It’s been over one hundred years since a wild salmon last swam through this reach of the Klamath River,” said Damon Goodman, a regional director for the nonprofit conservation group California Trout. “I am incredibly humbled to witness this moment and share this news, standing on the shoulders of decades of work by our Tribal partners, as the salmon return home.”

The dam removal project was completed Oct. 2, marking a major victory for local tribes that fought for decades to free hundreds of miles (kilometers) of the Klamath. Through protests, testimony and lawsuits, the tribes showcased the environmental devastation caused by the four hydroelectric dams, especially to salmon.

Scientists will use SONAR technology to continue to track migrating fish including Chinook salmon, Coho salmon and steelhead trout throughout the fall and winter to provide “important data on the river’s healing process,” Goodman said in a statement. “While dam removal is complete, recovery will be a long process.”

Conservation groups and tribes, along with state and federal agencies, have partnered on a monitoring program to record migration and track how fish respond long-term to the dam removals.