(Reuters) - The government on Thursday recommended the removal of four hydroelectric dams on the Klamath River in Oregon and California to aid native salmon runs and help resolve a decades-long struggle over allocation of scarce water resources.
The Interior Department proposal, which comes as the largest dam removal project in U.S. history is nearing completion in Washington state, concerns a system of dams that straddle the Oregon-California border.
The proposal to dismantle the dams owned by utility PacifiCorp coincides with a broader push by environmentalists and others to restore salmon fisheries in the Klamath Basin and elsewhere in the nation.
The dams recommended for removal, two in Oregon and two in California, block upstream spawning migrations of salmon and place juvenile fish at risk by slowing their return to the Pacific Ocean.
Removing them would open 420 miles of salmon habitat for the first time in 100 years, eliminate turbines that grind up fish and restore the Klamath River channel, according to the government analysis.
The recommendation stems from a 2010 agreement among competing Klamath Basin water users that called for the government to determine if removing the dams would restore failing salmon runs and lessen conflicts in regional water management.
The Klamath River contains several fish, including Coho salmon, on the federal threatened and endangered species list, and repeated droughts in the basin have periodically forced water managers to allocate flows to protected fish rather than to farmers for irrigation.
The recommendation, which came in an environmental impact statement released by Interior, follows years of legal wrangling and periods of low flows that saw massive die-offs of salmon, shut-offs of irrigation districts and tightening of rules for hydroelectric projects that caused them to operate at losses.
The near collapse of Klamath Basin Chinook salmon led the government in 2006 to severely restrict commercial and sport fishing in the Klamath River and along 700 miles of the California and Oregon coast.
In a statement, Interior Secretary Ken Salazar on Thursday described the dismantling of the dams as "a comprehensive solution addressing all of the needs of the Klamath Basin, including fisheries, agriculture, refuges and power."
Under the proposal, which must still gain congressional approval, the dams would be removed over 20 months at a cost of $450 million to be garnered from rate payers and bonds.
If the dams were to remain in place, PacifiCorp would incur more than $460 million in costs for relicensing, operation and maintenance of aging structures that have proved unprofitable, the analysis shows.
Glen Spain, regional director of the Pacific Coast Federation of Fishermen's Associations, said the analysis "confirms that dam removal is both feasible and cheaper than any other option." But Klamath County Commissioners have withdrawn their support for taking down the dams.
The largest dam-removal project in U.S. history is expected to be completed this summer with the dismantling of the second of two towering dams on the Elwha River in Olympic National Park in Washington.
The project is designed to allow salmon to return to their historic spawning areas and raise salmon counts from 3,000 to 400,000.
Editing by Cynthia Johnston and Todd Eastham