Grand Coulee Dam is a hydroelectric gravity dam on the Columbia River in the U.S. state of Washington. In the United States, it is the largest electric power producing facility^[1] and the largest concrete structure.^[2] It is the fourth largest producer of hydroelectricity in the world. The top producing dams are the Three Gorges Dam in China, the Guri Dam in Venezuela, and the Itaipu Dam on the border of Paraguay and Brazil.

The reservoir is called Franklin Delano Roosevelt Lake, named after the United States President who presided over the completion of the dam. The foundation was built by the MWAK Company, a joint effort of several contractors united for this purpose. Consolidated Builders Incorporated, including industrialist Henry J. Kaiser, completed the dam. The United States Bureau of Reclamation supervised the contractors and operates the dam. Folk singer Woody Guthrie was commissioned by the Bonneville Power Administration to write songs about the Columbia Basin Project; the songs Roll On Columbia and Grand Coulee Dam are part of that series.

The Grand Coulee Dam is almost a mile long at 5223 feet (1586 m). The spillway is 1,650 feet(503 m) wide. At 550 feet (168 m), it is taller than the Great Pyramid of Giza^[3]; all the pyramids at Giza could fit within its base. Its hydraulic height of 380 feet (115 m) is more than twice that of Niagara Falls. There is enough concrete to build a four-foot wide, four-inch deep sidewalk twice around the equator^[4].

Background

The dam was built under the auspices of the U.S. Bureau of Reclamation as part of the Columbia Basin Project for irrigation of desert areas of the Pacific Northwest and for the production of electricity.^[5] Central Washington's Columbia Basin was a slightly over-ambitious candidate for a dam. The Columbia was by far the largest river anyone had ever considered damming. A Spokane group wanted a safer 134-mile (216 km) gravity flow canal from the Pend Oreille River at Albeni Falls. And the original low dam design would have have been useful for regulating navigation flows, and for hydroelectic power, but it would have been too far below the top of the canyon to make it useful for irrigation of the fertile loess soil of the basin. The controvery over which project should go forward was a central issue of Washington state politics in the 1920s.^[6]

By the 1930s, after thirteen years of debate and several studies, and with the Depression in full swing, Roosevelt was eager for large public works. In 1933, President Franklin D. Roosevelt authorized the dam as a Public Works Administration project, and Congress appropriated funding for the low dam. Two years, and endless political machinations.^[7] later, the authorization was changed from the low dam, to the far more expensive, and technically challenging, high dam of today.

Construction

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

One of six new Francis turbines, rated at nearly one million hp, being installed in powerhouse #3

The primary goal of irrigation was postponed as the wartime need for electricity increased. Aluminum smelting was vital to the war effort, and to airplane construction in particular. The electricity was also used to power plutonium production reactors and reprocessing facilities at the Hanford Site, which was part of the then top-secret Manhattan Project.

The dam was instrumental in the industrial development of the Pacific Northwest.

Irrigation

The original goal of irrigation resumed after the war. A water distribution network was built using the adjacent Grand Coulee to hold the main reservoir now known as Banks Lake. Additional dams, siphons, and canals were constructed, creating a vast irrigation supply network called the Columbia Basin Project. Irrigation began in 1951.^[9]

Water is pumped up 280 feet (85 m) from Lake Roosevelt to Banks Lake using twelve 14-foot-wide pipes. Pumped-storage hydroelectricity capability was incorporated into the final six pumps. During low-demand periods, water is pumped into Banks Lake, to be used later during high-demand periods. Water flow is reversed, powering generators as it falls back into Lake Roosevelt. This function is used regularly when irrigation water demand is low and electricity demand is high.

Expansion

The interior of powerhouse #3. Also pictured is a gantry crane, once the world's largest.^[12]

The expansion of the dam also required the installation of over 20 km of oil-cooled cables. These 6" cables, made in Japan by Sumitomo Electric, are rated to a maximum potential of 525 kV and are connected to powerful pumps which circulate the oil through the cables during normal operation.

Environmental and cultural consequences

The dam had negative consequences for the local Native American tribes whose traditional way of life revolved around salmon. Grand Coulee Dam and nearby Chief Joseph Dam (built in 1953) permanently block anadromous fish,^[13] removing over a thousand miles of their traditional spawning grounds. The various confederated tribes of the Colville Indian Reservation live along the Columbia River. Grand Coulee Dam flooded over 21,000 acres (85 km²) of prime bottom land where Indians had been living for thousands of years, forcing the relocation of settlements and graveyards.^[14] The ancient and important salmon fishing site at Kettle Falls was inundated. The town of Kettle Falls, Washington was relocated. 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, plus annual payments of approximately $15 million.^[15]

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, The laser light show at Grand Coulee Dam is projected onto the dam's wall. The show includes full-size images of battleships and the Statue of Liberty, as well as some environmental comments. Tours of the new Third Powerhouse 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.

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.

Statistics

A 193 lb. (87.5 kg) nut and bolt, one of sixteen used to join sections of the generator shaft of a 75000 kW generator at Grand Coulee Dam in 1942

• Largest concrete dam and concrete structure in North America with 11,975,521 yd³ (9,155,942 m³) used]]^[16]
• Total length of dam: 5,223 ft (1,592 m)
• Length of main dam: 3,867 ft (1,178 m)
• Length of forebay dam: 1,170 ft (356 m)
• Length of Wing Dam: 186 ft (56 m)
• Hydraulic height: 380 ft (116 m)
• Height of dam from bedrock: 550 ft (168 m)
• Height above original streambed: 401 ft (122 m)
• Reservoir Lake Roosevelt stretches for 151 mi (243 km)
• Average release: 110,000 ft³/s (3,100 m³/s)
• 4 power plants, 33 generators
• Installed generating capacity: 6809 MW ^[17]

References

Bibliography

• Ray Bottenberg: Grand Coulee Dam (Charleston, SC: Arcadia Publishing, 2008).
• J. Harlen Brentz: The Grand Coulee (American Geographical Society, 1932).
• L. Vaughn Downs: The Mightiest of Them All: Memories of Grand Coulee Dam (American Society of Civil Engineers, 1993).
• Marcia S. Gresko: The Grand Coulee Dam (Blackbirch Press, 1999).
• Paul C. Pitzer: Grand Coulee: Harnessing a Dream (Pullman: Washington State UP, 1994).
• George Sundborg: Hail Columbia: The Thirty-year Struggle for Grand Coulee Dam (New York: Macmillan, 1954).
• Richard White: The Organic Machine: The Remaking of the Columbia River (New York: Hill and Wang, 1995).

External links

• Official web site - U.S. Bureau of Reclamation
• GrandCouleeDam.org Informational web site
• Grand Coulee Dam Columbia Basin Project Historical site Personal interest site maintained by Charles Hubbard
• University of Washington Libraries Digital Collections ? Grand Coulee Dam Photographs and pamphlets of the construction of the dam. Includes information about the recommendations for and against building the dam as well as images of land clearing activities by the Public Works Administration.
• Central Washington University Library Digital Collections The Rufus Woods Photograph Collection contains photographic prints and negatives of the Grand Coulee Dam in Washington State prior to, during and after construction. The photographs visually document the construction of the dam, the conditions in the Columbia River Basin throughout construction and the introduction of irrigation in north central Washington State

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