Water Reclamation
Water reclamation
The term "water reclamation" can be defined in different ways. In the early and mid-1900s, water reclamation referred primarily to supplying potable water to arid areas where water was not readily available, through the development of water projects such as dams and canals. Water reclamation can also mean collecting used water (i.e., wastewater ) and treating it for reuse for irrigation and other purposes.
The federal agency primarily responsible for water reclamation projects that provided a source of water to arid lands is the Bureau of Reclamation ,in the Department of the Interior. Formed in 1902 as the Reclamation Service and later renamed the Bureau of Reclamation in 1923, the agency's mission was "the construction and maintenance of irrigation works for the storage, diversion, and development of water for the reclamation of arid and semi-arid lands." This federal agency built dams, reservoirs, and other water development projects in the 17 western states of the United States. The mission of the Bureau of Reclamation in the early 1900s was to serve the irrigation needs of farms of 160 acres (65 ha) or less. By the 1930s the bureau's constituency expanded to larger farms, towns, and cities. The Army Corps of Engineers and the Department of Agriculture Soil Conservation Service (now called the Natural Resources Conservation Service) are also responsible for providing irrigation water in addition to providing flood control, drainage , and navigation.
During the early 1900s, water reclamation projects were a means of providing an opportunity for people to settle in the western United States. The projects provided inexpensive, government-subsidized water used for transportation , farming, industry, and by municipalities for drinking water and electricity. During the Depression era of the 1930s, the Bureau of Reclamation and the Public Works Administration worked together on water projects, which became an important part of the nation's economic recovery program.
In 1959, a Senate Select Committee on National Water Resources was formed to determine whether more water projects were necessary. After two years of investigations, the committee highlighted three main concerns: possible water shortages in the future, decreasing water quality , and possible flooding . Some of the recommendations made by the committee to address these concerns included increased regulation of stream flows by reservoirs, improved groundwater use, improvements in water use efficiency, and increased use of desalination and weather modification .
As a follow-up to the recommendations by the Select Committee on Natural Water Resources, President Kennedy created a Water Resources Council headed up by the Secretaries of the Interior, Health, Education and Welfare, and the Army to make biennial nationwide water project studies and to develop uniform regulations for evaluating water projects. With the advent of the environmental movement during the 1960s and the lowered unemployment relative to the 1930s, water reclamation projects became less of a national priority. By the 1970s, President Carter proposed that the costs of water projects be shared by the local water users. President Carter also proposed that water reclamation projects be evaluated based on economic, environmental, and safety criteria. During President Reagan's tenure, the criteria used to evaluate the feasibility of water projects were relaxed; however, President Reagan continued support of local cost sharing.
Over the years, there have been numerous water reclamation projects. A year after the formation of the Bureau of Reclamation, the agency was working on six projects. By 1907, it was participating in the development of 27 water projects. From 1905-1991, the Bureau of Reclamation built over 493 reservoirs and diversion dams, 7,670 mi (12,341 km) of irrigation canals, 1,440 mi (2,317 km) of pipelines and tunnels, and 53 hydroelectric power plants . All the larger rivers in the U.S. have been altered in some way by water reclamation projects. For example, the Columbia River has 28 dams. Some of the larger water reclamation projects include the Central Arizona Project (a massive canal system that diverts over 1.2 million acre-feet [1.5 billion m3] of water per year from the Colorado River ), Bonneville Dam in Oregon, Grand Coulee Dam in Washington, Marshall Ford Dam in Texas, Teton Dam in Idaho, Garrison Dam in North Dakota, Tellico Dam in Tennessee, Hoover Dam in Nevada, Glen Canyon Dam in Arizona, Imperial Dam in California, and the Central Valley Project in California. Costs of these projects were large. For example, the California Central Valley Project cost over $950 million. The farmers, large and small, have paid only a small portion of overall costs of water reclamation projects. An estimated 4% of the total cost of the California Central Valley Project, equal to about $38 million, was repaid by the farmers who benefitted from the water project.
Important wildlife habitat and wildlife were lost as a result of these efforts to create massive dams. Dam building along the Colorado River has led to the decline of eight species of fish that are now considered Endangered. Habitat loss can result from flooding areas to create reservoirs or from cutting off water and nutrients from naturally occurring periodic flooding. During dam construction, stream-side habitat communities can be altered and destroyed from diverting the course of the river and excavation and dredging activities related to dam building. The ecology of these areas typically changes from that of a river to that commonly found along lakes and reservoirs.
Another ecological change occurs from dams cutting off sediment suspended in rivers from flowing downstream. As a result, sediment builds up in dams, reducing their volume and lowering their life expectancy. For example, the volume of Lake Waco in Texas was reduced by half over a 34-year period. When dams trap silt and sediment, erosion can result down stream. Below the Hoover Dam, millions of cubic yards of sediment were eroded over a 100 mi (160 km) stretch of the Colorado River.
Water reclamation projects continue on a much smaller scale today. Another method in which to obtain water for irrigation purposes is using water twice—once for domestic purposes and a second time for irrigation of lands such as farms and golf courses . Reclaiming used water occurs in the U.S. and throughout the world. Israel reclaims over 70% of its used water, or waste water, to irrigate over 47,000 acres (19,000 ha) of farm land. By the end of the 1990s, Israel plans to supply over 16% of its total water needs by reclaiming waste water. The city of Los Angeles, California, reuses its treated waste water to recharge its underground aquifers, which it taps for drinking water. In Arizona, the city of Tucson plans to reuse water to meet over 19% of its total water needs while Phoenix receives over 70,640 ft3 (2,000 m3) of fresh water from the Bureau of Reclamation in exchange for every 105,960 ft3(3,000 m3) of reclaimed water used by the nearby irrigation district. The city of St. Petersburg, Florida, has a unique system in which it provides two sources of water; one source is potable water used for drinking, cooking, washing, etc. and the other source of water is reclaimed water from wastewater that is reused for irrigating parks, median strips along roads, and residential lawns. Because the treated wastewater contains nutrients such as nitrogen and phosphorus , less fertilizer is needed when used for irrigation.
Securing sufficient amounts of water while sustaining a healthy environment can be accomplished in many ways using all types of water reclamation projects including waste water reuse. Water conservation , efficiency of use, and reuse will likely be playing larger roles in ensuring adequate water supplies in the future.
[Marci L. Bortman ]
RESOURCES
BOOKS
Gottlieb, R. A Life of Its Own, The Politics and Power of Water. New York: Harcourt Brace Jovanovich, 1988.
Hunt, C. E., and V. Huser. Down by the River, the Impact of Federal Water Projects and Policies on Biological Diversity. Washington, DC: Island Press, 1988.
Outwater, A. Water, A Natural History. New York: Basic Books, 1996.
Postel, S. Last Oasis: Facing Water Scarcity. The Worldwatch Environmental Alert Series. New York: W.W. Norton & Company, 1992.