Ice Harbor Dam, Lake Sacajawea, and associated facilities are operated for Hydropower, Navigation, Fish & Wildlife, Recreation, Water Quality, and Irrigation. Ice Harbor Lock and Dam was the first of four dams constructed as part of the Lower Snake River Project, authorized in the Rivers and Harbors Act of 1945. Construction began in 1956, and three turbine units were operational in 1961. Three more turbine units were installed and operational in 1976. Lake Sacajawea extends 32 miles upstream to Lower Monumental Dam.