A U.S. agency seeking to restore habitat for endangered fish gave final approval on Thursday to decommission four dams straddling the California-Oregon border, the largest dam removal undertaking in U.S. history.

Dam removal is expected to improve the health of the Klamath River, the route that Chinook salmon and endangered coho salmon take from the Pacific Ocean to their upstream spawning grounds, and from where the young fish return to the sea.

The U.S. Federal Energy Regulatory Commission issued an order surrendering the dam licenses and approving removal of the dams.

The project has long been a goal of several native tribes whose ancestors have lived off the salmon for centuries but whose way of life was disrupted by European settlement and the demand for rural electrification in the 20th Century.

Read more: Reuters