Garrison Dam Tribes. Construction on the $300-million dam project began in 1947, and its embankment was enclosed in April 1953. The dam was dedicated by President Eisenhower two months later. The Corps of Engineers completed earthwork in the fall of 1954. Garrison Dam is one of six Missouri River Main stem dams operated by the U.S. Army Corps of Engineers, Omaha District. The dam upstream of Garrison Dam is Fort Peck Dam (near Fort Peck, Montana). The dams downstream of Garrison Dam are: Oahe Dam (near Pierre, South Dakota), Big Bend Dam (near Fort Thompson, South Dakota), Fort Randall Dam (near Pickstown,
Wells Dam Wells Dam Wells Dam is a hydroelectric dam located on the Columbia River, downstream from the confluence of the Okanogan River, Methow River, and the Columbia River in Washington state. The dam, associated structures, and machinery make up the Wells Hydroelectric Project. It is owned and operated by Douglas County Public Utility District. It has produced electricity since August 22, 1967. Its operating license from the US Federal Energy Regulatory Commission is next up for renewal in 2052. In addition to the two public utility districts, the project provides electricity to Puget Sound Energy, Portland General Electric, PacifiCorp, Avista Corporation,