This EIS analyzes the environmental impacts of developing additional facilities and modifications to existing facilities built for the Lower Snake River Compensation Plan in order to mitigate impacts to natural populations of spring chinook salmon in the Grande Ronde and Imnaha River basins caused by DOE’s Bonneville Power Administration’s operation of four federal dams on the lower Snake River. The U.S. Fish and Wildlife Service, U.S. Department of the Interior, and the U.S. Forest Service, Department of Agriculture, are cooperating agencies.