Four dams on the Klamath River.

Four dams on the Klamath River, including three in California's Siskiyou County, could be removed by 2020 under an "agreement in principle" signed in November by the Department of the Interior, state officials in California and Oregon, and utility company Pacificorp.

Indian tribes, fishermen, local governments in Humboldt County and environmentalists have sought dam removal for years because the structures block access to historic salmon spawning grounds and alter the river's natural flow. In 2001, Klamath Basin farmers and federal officials engaged in a physical standoff when the Bureau of Reclamation wanted to release more water to aid fish. The following year, the bureau provided more water to farmers, leading to poor downstream conditions and a huge die off a salmon while they migrated upriver.

Under the agreement, the federal government has until March 2012 to assess the costs and benefits of dam removal. California agreed to put up $250 million for dam removal, while Pacificorp would pay $200 million through a 2% surcharge on ratepayers. In the meantime, Pacificorp will provide an additional $500,000 annually for salmon fishery restoration measures. The ultimate dam removal and river restoration project would require the passage of legislation in Sacramento, Salem and Washington.