Cowlitz River Project History

1923 - The City of Chehalis obtains the right from the State of Washington to develop hydroelectric power on the Cowlitz River.
• 1926 - Chehalis sells its rights to a Minnesota-based private developer, which receives a permit in 1933 to build a dam where Mayfield Dam exists today. However, the developer never starts construction.
• 1946 - Tacoma Power purchases the development rights from the Minnesota company and applies for a permit from the Federal Power Commission.
• November 1951 - The Federal Power Commission grants a 50-year federal license to Tacoma Power to build and operate Mayfield and Mossyrock dams.
• 1955 - Tacoma Power begins building Mayfield Dam but work stops because of litigation.
• 1959 - Construction resumes and continues through completion.
• 1962 - Tacoma Power finishes building Mayfield Dam, which creates beautiful Mayfield Lake.
• March 30, 1963 - Mayfield Dam, Tacoma's first dam on the Cowlitz River, is officially dedicated and energized.
• March 10, 1965 - Tacoma Power breaks ground for Mossyrock Dam.
• October 13, 1968 - The first generating units at Mossyrock Dam are tested and the first commercial power is generated.
• May 16, 1969 - Mossyrock Dam is officially dedicated.

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