After dissolved solids from agricultural runoffs built up in the Kesterson Reservoir ponds and created a toxic environment for breeding migratory fowl, media attention and public outcry induced the U.S. Department of the Interior to close the poisoned Kesterson National Wildlife Refuge.
California’s Central Valley once contained most of the state’s 5 million acres of wetlands. In the 1900’s, an estimated 60 million birds using the so-called Pacific Flyway wintered there. The expanse of wetlands shrank as the area became important agriculturally, and by the end of the century only about 300,000 acres remained, while the number of birds using the flyway dropped precipitately to about 2.5 million, roughly 4 percent of their former number.
The change developed slowly over decades as farmers destroyed suitable nesting sites and wintering grounds and began cultivating land that had high concentrations of selenium and other heavy metals. The dangers that some of these lands posed was known as far back as 1857, when horses and cattle died after grazing there. The precise cause was not identified until 1933, when a chemist with the U.S. Department of Agriculture determined that selenium was the culprit. Eight years later, the agriculture department determined that areas of the San Joaquin Valley also had high levels of selenium, and the head of the U.S. Geological Survey recommended that all high-selenium lands be identified and barred from agricultural use.
Those warnings were not heeded, however, and throughout the 1960’s, large irrigation projects were built in these areas. Construction on the Kesterson Reservoir, designed to be part of a system to remove agricultural runoff from 1.4 million acres of farmland, was begun in 1972 by the U.S. Bureau of Reclamation. The bureau had carried out an extensive program of irrigation projects during the fifty years preceding, which turned the alkaline soils in the Central Valley of California into rich farmlands. One-fourth of all fruits and vegetables grown in the United States were produced there. From an economic standpoint, there were strong incentives to keep the land productive.
Because of the nature of the soil in the valley and the impermeable layer of clay underneath it, a series of drainage pipes had been placed in the subsoil to carry away the water used for irrigation (in places where the pipe was not laid, salt migrated to the surface, making the land unsuitable for farming). The planners of the Kesterson Reservoir intended that the spent water be channeled to a series of holding ponds and from there eventually to the Pacific Ocean. More than 1,200 acres of ponds held the drainage from 42,000 acres of farmland and provided a habitat for local and migratory birds. Drainage water began flowing into the system in 1978, but only in 1981 did the drainage become the primary source of water for the wildlife refuge. The original plan had included a canal to carry the water in these holding ponds to San Francisco Bay, but it was never built, at first for lack of funding and later because of environmental concerns.
As early as 1980, it was observed that the refuge ponds contained only one small species of fish. In 1983, Harry M. Ohlendorf, a research biologist with the U.S. Fish and Wildlife Service, discovered a large number of dead and deformed birds that had become contaminated with the trace element selenium. Selenium is a critical agricultural micronutrient, but the elevated levels in the drainage waters (between 24 and 430 micrograms per liter) had led to significant waterfowl deformities and deaths. Studies revealed that 6.6 percent of the stilt eggs examined in 1983 were either dead or had deformities. American coots and eared grebes were also found dead of selenium toxicosis,
Evaporation ponds at the Kesterson National Wildlife Refuge in central California.
By the breeding season of 1984, when more than sixteen thousand birds died, it was clear that the cause was the contaminated water being funneled into the holding ponds. Jim Claus, who owned land adjacent to Kesterson, filed suit to stop the inflow of water and contacted various news media to report the environmental damage. In February, 1985, the California Water Resources Control Board ordered the Bureau of Reclamation to clean up the refuge within three years or close it down.
The single event that galvanized local as well as national opinion and forced the government to seek a solution was the airing on March 10, 1985, of a segment on the 60 Minutes television newsmagazine that addressed the selenium contamination of the Kesterson National Wildlife Refuge. The sight of deformed and dying birds, and of birds sitting on eggs that would never hatch, outraged viewers, and the resulting public outcry was enough to induce the Department of the Interior to close the refuge on March 15, 1985. To prevent birds from stopping at Kesterson, employees of the Fish and Wildlife Service fired blank ammunition; later, automatic cannons were set up to fire harmless blasts at intervals to keep the birds away.
In 1969, the U.S. Congress passed the National Environmental Policy Act,
After evaluating the extent of the disaster, the Bureau of Reclamation
Some of the remaining contaminated water in the refuge was redirected to the California Aqueduct, which provides water for the entire city of Los Angeles. Over the years, a certain amount of the water had disappeared through subsurface migration into underground aquifers. Scientists were surprised to find that this drainage, at a flow rate of about 150 feet per year, had not resulted in high amounts of selenium; instead, a biological mechanism seemed to have been operating that stabilized the selenium.
The process of irrigation in California and a number of other western states was inherently problematic. At that time, nearly 80 percent of all water consumed in California, for example, was used for agricultural purposes. Because much of the irrigated land is semiarid and rich in selenium, all drainage water should have been removed to prevent salinization of the fields. The best way to remove the water was thought to be sending it to the Pacific Ocean, but in many cases it was instead being reused by other farmers, which resulted in ever-higher concentrations of selenium and other metals.
Hundreds of evaporation ponds are in existence throughout the western United States. Some are used to attract waterfowl, but many are essential for turning marginal land into productive farmland. Periodic testing of water and assessment of the health of bird populations would help prevent disasters such as the one that took place at the Kesterson National Wildlife Refuge. Irrigation should not be allowed to be continued in areas where the drainage water cannot be removed, but the economic costs to businesses, taxpayers, and consumers are often considered prohibitive. Similar arguments were used against the proposed ban on the use of DDT, but there the risk to wildlife was found to be of greater concern than the increased costs.
After the disaster at the Kesterson refuge, research biologists began to investigate other federal reserves. Joseph Skorupa,
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Benson, S. M., et al. “Groundwater Contamination at the Kesterson Reservoir, California: Hydrogeologic Setting and Conservative Solute Transport.” Water Resources Research 27 (June, 1991): 1071-1084. A fairly technical but very informative article, with a particularly interesting discussion on the underground plume of contamination from the reservoir. -
Benson, S. M., M. Dalamore, and S. Hoffman. “Kesterson Crisis.” Journal of Irrigation and Drainage Engineering 119 (May/June, 1993): 471-483. An informative discussion of effluent contamination. Includes drainage maps and a useful bibliography. -
De Villiers, Marq. Water: The Fate of Our Most Precious Resource. Toronto: Stoddart, 1999. Highly readable account of water management policies throughout the world. -
Reisner, Marc. Cadillac Desert: The American West and Its Disappearing Water. Rev. ed. New York: Penguin Books, 1993. An excellent source for understanding the politics involved in water use in the western states. -
Zawislanski, Peter T., Tetsu K. Tokunaga, and Sally M. Benson. “Bare Soil Evaporation and Solute Movement in Selenium-Contaminated Soils of Kesterson Reservoir.” Journal of Environmental Quality 21 (July-September, 1992): 447-457. Focuses on the movement of selenium through the subsoil and water table and includes an extensive bibliography and diagrams of the Kesterson Reservoir.
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