Colorado River water Summary

  • Last updated on November 10, 2022

Diversion of the Colorado River has helped make possible the economic growth of the American West, particularly Southern California and the city of Los Angeles. The river’s water is used for irrigation and the generation of electric power, and the lakes created by damming the river are recreation centers. Without the Colorado’s water, it would be difficult to imagine the American Southwest as it exists in the twenty-first century.

Unlike other rivers that have been important to American economic development, the Colorado River is not a large river, and it has never played an important role in the transportation of goods and people. Because it is essentially an untamed river, the Colorado’s flow varies dramatically from a few thousand cubic feet per second to more than two hundred thousand cubic feet per second. Not explored until 1869, the Colorado has become the source of water and electric power for much of the American West.Colorado River waterWater;Colorado River

Hoover Dam

In the arid West, politicians long had their eyes on the Colorado River as a source of water for their states. In 1922, California, Arizona, and Nevada (the lower basin states), together with Colorado, Utah, Wyoming, and New Mexico (the upper basin states), negotiated the Colorado River Compact at the direction of Secretary of Commerce Herbert Hoover, HerbertHooverHoover Dam. This agreement allocated the estimated flow of 17.5 million acre-feet per year. Some 7.5 million acre-feet were allocated to each basin, with a bonus of 1 million acre-feet given to the lower basin and 1.5 million acre-feet reserved to Mexico. Two problems remained: calculating the flow estimate and determining how to draw on the Colorado’s water.

Rainfall had been plentiful in the Rockies during the early twentieth century, so the estimate of 17.5 million acre-feet seemed accurate. It was not. The rainfall during the early twentieth century was abnormally high, and the Colorado River has rarely produced 17.5 million acre-feet in flow since the compact was signed. Since the 1930’s, the flow has averaged 11.3 million acre-feet per year. That problem would crop up in the future–the more immediate issue after the compact was agreed to was how to tap the river’s water.

In 1930, Congress authorized Boulder Dam (renamed Hoover Dam), and construction began in 1931. It was jointly carried out by eight engineering firms, some of which (such as the Bechtel Corporation) would become massive construction firms in the future. Construction of Boulder Dam provided a stimulus to the Western economy, as large numbers of men worked on the project. The dam became a model for later projects throughout the world. It was completed and the first electric power generated in fall of 1936. Hoover Dam generated such a large amount of electric power that it paid for itself. Lake Mead extended upstream for a hundred miles, providing the water that could be used to irrigate and provide drinking water for California and the Southwest.

Boulder Dam, in 1938, viewed from the high mountain downstream.

(Library of Congress)

The population of California;growth ofCalifornia was growing during the 1930’s, and the Colorado River was seen as a short-term solution to its water needs. Initially, much of California’s water allocation went to agriculture, with nearly 3 million acre-feet irrigating the truck farms of the Imperial Valley. By the 1950’s, California was already using its 4.4 million acre-foot allotment under the Colorado River Compact and was searching for additional sources of water both within its borders and elsewhere. It soon began to pump 700,000 additional acre-feet from the river. Initially, this was not a problem, but as the population of the intermountain states began to grow, they too wanted to ensure their allocations from the river. The small gambling town of Las Vegas;growth ofLas Vegas, Nevada, started to grow during the 1950’s, creating a significant new demand for electric power and water in the desert. Not only did the citizens of Las Vegas need a large amount of water for drinking and irrigation of their lawns, but the hotels of the city often had large decorative fountains and lakes. The Mirage Hotel, for example, uses more than 1 million gallons of water a day. Abundant water was part of the ambience of the Las Vegas hotels, an ambience that was enormously profitable to the city.

Dams Along the River

The Bureau of Reclamation turned again to the Colorado in 1956 with the construction of Glen Canyon DamGlen Canyon Dam, which formed Lake Powell. Between them, Lake Mead and Lake Powell have four times the capacity of the yearly flow of the Colorado, evening out the flow and providing a continual source of irrigation water and electric power. In 1964, the bureau wanted to construct another dam across the Colorado that would have drowned the Grand Canyon National Monument. Conservationists defeated the project, pointing out the scenic value of the canyon that would be flooded, as well as the waste through evaporation of the new lake.

The demand for water and electric power in the West appears insatiable. Other sources of water, including underground aquifers, have been tapped, as the Colorado is incapable of supplying all the water that is needed. The Colorado seemed capable of supplying at least a sizeable part of the water for the West, at least in 1999 when both Lakes Powell and Mead were full. Since 1999, the Rockies have experienced much less snowfall than usual. By 2007, Lake Mead was half empty, and Lake Powell was also in decline. The Colorado fed the dream of making the West bloom, and for a time it helped to make the dream a reality. By the early twenty-first century, the dream was coming into question.

Further Reading
  • Gertner, Jon. “The Future Is Drying Up.” New York Times Magazine, October 21, 2007, pp. 68-77, 104, 154-155. Examines the future role of the Colorado River as the climate of the Southwest becomes drier.
  • Pearce, Fred. When the Rivers Run Dry. Boston: Beacon Press, 2006. Places the Colorado in the wider question of water shortage.
  • Reisner, Marc. Cadillac Desert. Rev. ed. New York: Penguin Books, 1993. The classic book dealing with water in the American West, with two chapters devoted to the Colorado.
  • Reisner, Marc, and Sarah Bates. Overtapped Oasis: Reform or Revolution for Western Water. Washington, D.C.: Island Press, 1990. Account predicting a water crisis in the West, with extensive attention to the Colorado.
  • Ward, Diane Raines. Water Wars. New York: Riverhead Books, 2002. Deals with the political and engineering questions surrounding water, with attention to the Colorado.

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