Chinook salmon return to Klamath River habitat after four US dams removed

· Climate · United States

A new study has found that removing four dams on the Klamath River, which runs through Southern Oregon and Northern California, allowed Chinook salmon to return to historical habitat. The river was heavily dammed over the 20th century, blocking spawning salmon, and the population that spawned there declined by roughly 90 percent. Dam removal is one of the largest river-restoration efforts undertaken in the United States, and the study's finding that fish have recolonised habitat above the former barriers is the first evidence that the intervention is producing the intended ecological result. The result is being watched as a test case for whether large-scale dam removal can reverse declines in migratory fish populations.

Why it matters：Dam removal is being tested worldwide as a river-restoration tool, so evidence that fish recolonise former habitat informs decisions on ageing barriers and hydropower decommissioning.

Key points

  • Four dams were removed from the Klamath River in Oregon and California
  • Chinook salmon populations there had fallen by roughly 90 percent
  • Salmon have returned to historical habitat above the former dams

Sources (original reporting)

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