Bonneville Dam officially goes into service on June 6, 1938.

  • By David Wilma
  • Posted 7/03/2006
  • Essay 7823
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On June 6, 1938, the U.S. Army Corps of Engineers officially places Bonneville Dam on the Columbia River into service. Bonneville is a run-of-the-river dam that will generate more than a million kilowatts of electricity, allow passage of shipping up and down the river, prevent flooding, and permit the migration of salmon. The dam will give its name to the Bonneville Power Administration created to distribute hydroelectric power produced by Columbia River dams.

Since settlement, shippers and farmers each had designs on improvements to the Columbia River. Shippers wanted to overcome the falls, rapids, and periods of low water, and the farmers wanted to tap the river for irrigation. The U.S. government, through the Army Corps of Engineers, undertook the first improvements to navigation, but large-scale irrigation faltered for want of stable funding. In the 1890s, the development of long-distance transmission of electricity brought the river's immense hydroelectric potential into the sights of electrical utilities.

In 1907, President Theodore Roosevelt's Inland Waterways Commission stressed a need for coordination between projects that benefited flood control, navigation, irrigation, and electricity generation. Congress was slow to respond, but in the 1920s funded some Corps of Engineers studies on the best way to use and improve the Columbia. The Corps "308 Report" (named after the 1925 House of Representatives document number) issued in 1932 recommended 10 dams on the Columbia between Canada and the Cascades at the head of tidewater.

The first project was Bonneville Dam by the Corps of Engineers at the Cascades of the Columbia where a canal and locks had been serving shipping since 1896. The dam would replace the canal, control flooding downstream, and provide electric power. Construction began in 1933 at a time when the jobs created helped relieve the unemployment of the Great Depression.

The spillway dam -- 1,450 feet long and 197 feet high -- regulated the height of water and was built from the Oregon shore to Bradford Island then to the Washington side. Between the island and the Oregon side the penstocks and power house generated 43,200 kilowatts of electricity. Next to the powerhouse, a lock, 75 feet wide and 500 feet long, lifted ships 50 feet to the reservoir beyond. Bonneville is a run-of-the river dam which allows all the water that flows downstream to flow through the spillways rather than impounding the water. The powerhouse was expanded during World War II and a second powerhouse was completed in 1982 capable of producing 1.084 million kilowatts. In 1993, the lock was replaced with a wider and longer version.

The steel Bridge of the Gods (1926) upstream was raised 44 feet to provide 135 feet of clearance for vessels on Lake Bonneville.

The 308 Report briefly mentioned providing for fish migration and the fish-ladder system to accommodate migrating salmon was designed after construction started. This system did not completely compensate for the loss of the free flowing river. Some returning fish could not find the ladders, many fingerlings headed downstream became trapped in power turbines, and during dry years, water releases were insufficient to carry smolts to the sea. Construction of dams upstream helped push several salmon runs to the threat of extinction.

Bonneville was named for U.S. Army Captain Benjamin Eulalie de Bonneville (1796-1878) who was the first commandant of Vancouver Barracks.

Sources: Dorothy Johansen, Empire of the Columbia, 2nd Ed. (New York: Harper & Row, 1957, 1967), 514-519; Stewart H. Holbrook, Rivers of America: The Columbia (New York: Rinehart and Co., 1956), 283-299; The Bonneville Lock and Dam Fact Sheet, brochure, U.S. Army Corps of Engineers, Bonneville Lock and Dam website accessed June 23, 2006 (; The Columbia River System: The Inside Story (Portland: U.S. Bureau of Reclamation, et al., 1991), 14; Craig Holstine, Richard Hobbs, Spanning Washington: Historic Highway Bridges of the Evergreen State (Pullman: Washington State University Press, 2005), 104-105; Oral Bullard, Crisis on the Columbia (Portland: Touchstone Press, 1968), 67-79.

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