The controversy surrounding the proposed removal of four dams along the Klamath River in southern Oregon and northern California has a new facet following the release of a two new reports by the U.S. Department of the Interior.

The first report, titled "Klamath Dam Removal Overview Report for the Secretary of the Interior: an Assessment of Science and Technical Information," is the product of two years of scientific and technical studies conducted to determine the advantages and disadvantages of removing the dams as per the Klamath Hydroelectric Settlement Agreement (KHSA).

The KHSA seeks the removal of four Klamath River hydropower plants and dams -- 90.338-MW J.C. Boyle, 20-MW Copco 1, 27-MW Copco 2, and 18-MW Iron Gate -- and the transfer of the non-powered Keno Dam to Interior.

The report is intended to inform the public and legislators of the KHSA's economic, biological, recreational and social impacts prior to a Secretarial Determination, according to an Interior release.

"The science and analyses presented in these reports are vital to making an informed and sound decision," says Secretary of the Interior Ken Salazar.

The report is available in its entirety here.

Interior's second report, titled "Klamath River Basin Restoration Nonuse Value Survey Final Report," is an updated version of its Economics and Tribal Summary Technical Report.

Proponents of dam removal note that this report anticipates benefits to include an improved salmon and trout habitat and the creation of 1,400 construction jobs during the year it would take to remove the dams. Long-term, the report indicates Klamath basin restoration could add an additional 4,600 jobs.

Meanwhile, the opposition is supported by the report's indication for increased flooding risk and a cut in electrical production. The report also puts a price tag of more than US$290 million on removal of the dams.

A summary of key conclusions from both reports is available here.

Salazar must decide by March 31 whether Interior will recommend the dams' removal. If he does, the governors of Oregon and California will then have 60 days to either concur or veto the plan.