On September 1, 1967, the first commercial electricity from Seattle City Light's new Boundary Dam arrives in Seattle. The thin-arch, concrete dam sits in Box Canyon on the Pend Oreille River in northeastern Washington. Its four generators produce 600,000 kilowatts of current, more than any other powerhouse on the City Light system.
Current is shipped only a short distance to the transmission lines of the Bonneville Power Administration. Through a "wheeling" arrangement (the transmission of electricity produced by one utility through facilities owned by another for a fee), the Bonneville Power Administration transmits an equivalent amount of power to Seattle, 300 miles away.
The power house was built completely underground because there was no room in the narrow canyon for conventional construction. Room was left for more units and in 1985, two more generators were completed. By 1999, Boundary supplied one-half of the hydro-electricity for Seattle, 23 percent of the city's total.
When City Light planned a $143 million, 12-year rehabilitation of the dam and power house, City Light employees bid on the project. Their proposal was 25 percent below the estimate and they got the job.
Seattle City Light Annual Report - 1986, p. 6; Seattle City Light Annual Report - 1985, p. 4; Seattle City Light Annual Report - 1967, pp. 3, 23; Seattle City Light Annual Report - 1986 , p. 11; Seattle City Light Annual Report - 1964, p. 6; Seattle City Light Annual Report - 1963, p. 8; Seattle City Light Annual Report - 1962, pp. 12-13; Seattle City Light Annual Report - 1961, p. 3; Seattle City Light Annual Report - 1959, p. 4; Seattle City Light Annual Report - 1958, p. 6; "Braman Hails Dam as Boon to Recreation," The Seattle Times, September 29, 1967, p. 6; Seattle City Light 1996 Annual Report, 4; Seattle City Light 1999 Annual Report, 9; Seattle City Light, "Our Electricity, Our Environment," brochure, 2000; Vera Springer, Power and the Pacific Northwest: A History of the Bonneville Power Administration, (Portland: U.S. Department of the Interior, 1976), p. 61. .
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