Copco, California — The Yurok Tribe has been tied to the Klamath River in Northern California, and the abundant salmon that once swam through it, for 10,000 years.

"One of our oldest stories talks about the connection between us and the river and the salmon in it," said Frankie Myers, a member of the tribe.

But the essential artery was blocked more than a century ago when construction started on four dams along the Klamath in Northern California and Southern Oregon. The dams generated power that fueled western expansion but devastated the salmon population, which could no longer swim upstream to spawn. 

The stagnant water behind the dams became a toxic stew of green algae.

"Without salmon in the river, there's no need for the Yurok people to be here," Myers told CBS News.

Myers said the dams are "a monument to manifest destiny. This idea that we're not a part of nature. It's here for our use and we can do whatever we want with no consequences."

But after decades of conflict and tribal activism against the dams, the once shackled Klamath is being set free. The dams, which no longer generate much electricity, are being torn down in a $450 million deconstruction project.

"We believe it may be the largest dam removal and salmon restoration project ever undertaken anywhere in the world," said Klamath Renewal Corporation CEO Mark Bransom.

But the removal process is not without its issues. Last week, at the base of another dam, hundreds of thousands of hatchery salmon were killed, likely by high water pressure as they passed through a tunnel opened to let the river flow through.

Once the dams are completely removed, native salmon populations are expected to return. Seeds are also being spread to regrow plants on land that drowned decades ago.

In:
• Oregon
• California

Ben Tracy

Ben Tracy is CBS News' senior national and environmental correspondent based in Los Angeles. He reports for all CBS News platforms, including the "CBS Evening News with Norah O'Donnell," "CBS Mornings" and "CBS Sunday Morning."

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