Monday, August 4, 2008
Grand Coulee Dam
Commenced during the Great Depression, Washington State’s Grand Coulee Dam, on the Columbia River about 88 miles (142 kilometers) west of Spokane, is a monument to engineering prowess and to the resolve of those people who for 23 years fought for its creation. The key to the Columbia Basin Irrigation Project, it provides the region with electric power, irrigation, and flood control and contributes to wildlife conservation. The Grand Coulee Dam is the largest concrete structure ever built in the United States and the nation’s largest hydroelectric facility. Its 550-foot-high (168-meter) gravity-type concrete wall, 500 feet (152 meters) thick at the base, spans a little under 1 mile (1,592 meters) and raises the water surface 350 feet above the former riverbed. Nearly 12 million cubic yards (over 9 million cubic meters) of concrete were needed to build it. Franklin Delano Roosevelt Lake (often simply called Roosevelt Lake), created by the dam, has a 600-mile (960-kilometer) shoreline and extends 150 miles (240 kilometers) to the Canadian border.
After several ruinous years of drought in the Northwest early in the twentieth century, the U.S. Reclamation Service Bureau (now the Bureau of Reclamation) considered pumping water from the Columbia River to irrigate agricultural land in eastern Washington, a region then served by artesian wells. In 1917 an Ephrata attorney named William Clapp proposed an alternative: build a high-level dam on the Columbia and raise water to the Grand Coulee, the 50-mile-long (80-kilometer) natural channel of the old riverbed, thereby opening up more than 1 million acres (403,230 hectares) of irrigated farmland. Rufus Woods, editor of the Wenatchee Daily World, publicized the notion a few months later. In 1919 the Michigan lawyer James O’Sullivan became interested enough to put it before the Reclamation Service, which directed Washington State’s Columbia Basin Survey Commission to include it in a current feasibility study focused on irrigating the basin by gravity canals from the Pend Oreille River. In the teeth of opposition from vested interests connected with the latter scheme, the dam’s protagonists managed to enthuse, among others, A. P. Davis, director of the Reclamation Service. At O’Sullivan’s prompting, Davis suggested that the state commission an objective report from Seattle engineer Willis Batchelor, who in 1921 recommended a dam on the Columbia, 220 feet (67 meters) above river level.
Several years of argument followed. In 1923 George Goethals of Panama Canal fame—apparently a paid prophet—endorsed the canal system, and two years later the federal Columbia Basin Survey Board of Engineers supported his view. But O’Sullivan, Woods, Clapp, and others unflaggingly kept the dam project alive, and in 1927 the U.S. Senate authorized the Army Corps of Engineers, under Major John Butler, to look for possible sites during a 1929 survey of the upper Columbia River. In June the Columbia River Development League was formed with Woods as president and O’Sullivan as secretary. The Wenatchee Daily World became its mouthpiece. Late in 1931 Butler told Congress that a dam was more economical than a gravity canal: besides providing irrigation and flood control, it would raise revenue from electrical energy. O’Sullivan lobbied for authorization, and the Bureau of Reclamation soon recommended development of the project, almost in the form in which it was eventually realized. In 1933 the Columbia Basin Commission was established, and the state of Washington committed $377,000 to the Grand Coulee Dam. Recently elected President Franklin D. Roosevelt allocated $63 million under the Public Works Administration—a New Deal program. Through the Great Depression men and women from all over the United States would find work at the dam site: averaging 3,000, the labor force peaked at 6,000.
Excavation began in December 1933, and seven months later a $29.34 million contract for the foundation work was awarded to MWAK, a consortium formed by Silas Mason Company of New York City; Walsh Construction Company of Davenport, Iowa; and the Atkinson-Kier Company of San Francisco. Such a large undertaking called for a complex infrastructure: high-tension power lines were set up, the Columbia River was bridged, and over 30 miles (nearly 50 kilometers) of railroad and 60 miles of sealed roads were constructed. A contractor’s town, Mason City, and Coulee Dam, a government town, were built at the site. Four years later, a consortium formed by linking MWAK and the Six Companies—Kaiser Construction of Seattle; Morrison Knudsen of Boise, Idaho; Utah Construction; J. F. Shea Pacific Bridge; and McDonald and Kahn (all of San Francisco) and General Construction Company of Seattle—won the $34.4 million contract for the completion of the dam. Their bid was 80 percent of the only other tender.
The proposed height of the dam had been determined by the rather parochial notion that the impounded water should not back up beyond the Canadian border. Then the project’s main reason for being was irrigation—there were more droughts in the early 1930s—and flood control, rather than power generation. The Pacific Northwest had plenty of electricity and there was little prospect of industrial expansion. Therefore the original designs included a 350-foot (107-meter) “low” dam about 3,500 feet (1,070 meters) long, which would bring the water surface to only 150 feet (46 meters) above the river level. Should the demand for power increase, it was intended to later raise the wall. That was flawed thinking. Achieving a tight joint between the two parts of the wall would have been difficult, even dangerous; later changes to the turbines would be costly; and it was more expedient to construct the concrete foundation of a high dam at the start of the project. So, with the approval of Congress, the contracts were redrawn in June 1935 to build the high dam to plans by John Lucian, chief designer of BuRec engineers.
The main dam was completed by 1941 and work commenced on the pumping plant and powerhouses. The entry of the United States into World War II meant dramatic changes in priorities for the dam. Power generation was given first place because the region’s aluminum industry, a large consumer of electricity, was critical to the defense effort. Six generators were commissioned at the Grand Coulee, and two more were borrowed from the incomplete Shasta Dam project in northern California. Soon after the war, construction resumed on the pumping plant and in 1951 the irrigation system was inaugurated. Six huge pumps lifted water through 280 feet (85.6 meters) from Roosevelt Lake to Banks Lake equalizing reservoir in the Grand Coulee. In 1973 two more reversible pump-generator units were installed, followed by another four late in 1983. Feeding more than 300 miles (480 kilometers) of associated canals, and nearly 5,500 miles (8,800 kilometers) of laterals, siphons, and drains, the pumps can fully supply almost 1.1 million acres (about 440,000 hectares) of formerly dry land. They are not yet being used at their full capacity.
The reversible pump-generators installed could of course be used for power generation, augmenting the already remarkable output of the Grand Coulee Dam, whose power production facilities are by far the largest in North America. Two plants, with a total of eighteen generators, were operational by 1951. A third, coming on line in 1975, increased capacity to about 7,200 megawatts. By 1978 the three were producing over 6,000 megawatts, and subsequently additional generators—the total number is now 33—have achieved an output of over 6,800 megawatts.
In the 1950s the American Society of Civil Engineers included the Grand Coulee Dam and the Columbia Basin Project among the seven civil-engineering wonders of the United States. The project has also been popularly and superlatively dubbed “the Eighth Wonder of the World,” “the Greatest Structure in the World,” “the World’s Greatest Engineering Wonder,” and “the Biggest Thing on Earth.”