Grand Coulee Dam

From Academic Kids

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Grand Coulee Dam

Grand Coulee Dam is a hydroelectric gravity dam on the Columbia River in Washington State, built by industrialist Henry J. Kaiser. Along with the Hoover Dam it is among the most famous dams in the United States. The reservoir it backs up is called Franklin Delano Roosevelt Lake, named after the United States president who presided over the conception and completion of the dam.

The scope and size of the dam are hard to comprehend. The dam is over a mile long and is taller than the Great Pyramid of Giza. In fact, all the pyramids at Giza could fit within the base of the Grand Coulee Dam. It is more than twice as tall as Niagara falls. When one first sees the dam the mind plays tricks of perspective; a truck at the base looks like an insect, rather than revealing the dam's true size.



The dam was built as part of the Columbia Basin Project for irrigation of desert areas of the Pacific Northwest and not, in fact, for the production of electricity. Excavation of the site began in December of 1933 as a public works project and finished toward the beginning of WWII. The initial construction plan was for a shorter dam with an option for later raising. During construction, the design was changed to the higher specification. Its height was determined by the point at which the reservoir started backing up into Canada.

Original construction

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Construction of the original dam. The left section would be blown up in the late sixties to make way for powerhouse #3

When the dam was completed in 1941 it was the largest dam in the world. The primary goal of irrigation was forgotten as the war time need for electricity increased. Aluminium smelting was vital to the war effort. The electricity was also used to produce uranium at the Hanford Site as part of the top secret Manhattan Project. The dam was instrumental in the industrial development of the Pacific Northwest.

The original goal of irrigation resumed after the war. A distribution network for water was built using the Grand Coulee, an ancient river bed about 600 feet above the height of the Columbia river. Additional dams, siphons and canals were constructed that turned the coulee into a vast supply network that allowed a desert to bloom. Irrigation began in 1951


Between 1966 and 1974 the dam was expanded to add Powerhouse #3. This involved blowing up the Northeast side of the dam and building a new forebay section. The addition made the dam more than a mile long and accommodated six new generators. The new turbines and generators, three 600 Mw and three 700 Mw units, are some of the largest ever produced. The expansion was completed in the early eighties and made the Grand Coulee Dam one of the largest hydroelectric producers in the world.

Environmental consequences

The dam did much good but had negative consequences for the local Native American tribes whose traditional way of life revolved around salmon. The Grand Coulee and Chief Joseph Dams permanently block anadromous fish, removing over a thousand miles of their traditional spawning grounds. The Colville tribe lived along the Columbia River, and after the dam was built their lands were flooded and they were forced to move. The environmental impact of the dam effectively ended the traditional way of life of the native inhabitants, who sued the government. The government eventually compensated the Colville Indians in the 1990s with a lump settlement of approximately 52 million dollars.

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Panoramic view of the dam, looking Southeast. Powerhouse number three, visible at the lower left of the dam, is large enough to hold five football fields end to end.

Touring the dam

The visitor center contains many historical photos, geological samples, turbine and dam models, and a well used theater. Since 1989, on summer evenings, a laser light show is projected onto the dam's wall. The show includes full size battleships and the statue of liberty, as well as some environmental comments. Tours of the new Powerhouse #3 are available to the public but have been scaled back for security reasons. Visitors are able to ride a glass elevator, on top of the forebay penstocks, 400 feet down to view the generators.


  • Largest concrete dam in North America, largest concrete structure in the United States with 11,975,521 yd³ (9,155,942 m³) used
  • Crest length, 5,223 ft (1592 m)
  • Dam height: 550 ft (168 m), about twice the height of the Statue of Liberty (
  • Hydraulic Height: 380 ft (116 m)
  • Reservoir Capacity: 421 billion ft³ (11.9 km³)
  • Average release: 110,000 ft³/s (3,100 m³/s)
  • 4 power plants, 33 generators, 6,809 MW power production capacity, 21,000 GWh per year
  • Largest hydroelectricity generator in the United States, third largest in the world.
  • Irrigation: over 500,000 acres (2,000 km²)
  • First water over the spillway: June 1, 1942
  • Owner/operator, US Bureau of Reclamation

Quotes about Grand Coulee Dam

Now the world holds seven wonders that the travelers always tell,
Some gardens and some towers, I guess you know them well.
But now the greatest wonder is in Uncle Sam's fair land,
It's the big Columbia River and the big Grand Coulee Dam. (...)
--from The Grand Coulee Dam by Woody Guthrie

See also

External links



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