California closer to desalination


Published: Tuesday, January 14, 2003 at 6:01 a.m.
Last Modified: Tuesday, January 14, 2003 at 12:46 a.m.

Facts

On the Net:

  • Metropolitan Water District of Southern California: http://www.mwd.dst.ca.us/
  • California Coastal Commission: http://www.coastal.ca.gov/web/

  • LOS ANGELES - California's epic quest for water, made more pressing by a Western drought and a cutback in the Colorado River supply, is turning toward what many see as an obvious source: the Pacific Ocean.
    For the most part, desalination has long been prohibitively expensive as a source of drinking water in California. But rising demand, dwindling supply, and new technology that makes it cheaper to take the salt out of sea water are changing the economics of desalination.
    "It is expensive, but it's not something of the other world anymore," said Adan Ortega, a spokesman for the Metropolitan Water District of Southern California, which serves 18 million customers.
    The MWD is approving plans to subsidize five desalination plants, proposals that were submitted by local water agencies. Together, the plants could supply up to 7 percent of MWD's customers by 2007.
    "Even though it only represents a small portion of the water we use, it's an additional supply," MWD chairman Phillip Pace said. "It's something everyone has an interest in."
    The MWD tentatively approved the proposals in December and expects construction to begin by 2005, pending environmental reviews. The five plants are expected to cost between $70 million and $300 million each.
    Elsewhere around the nation, a plant in Florida's Tampa Bay is scheduled to open this month, with a second one in the works. Texas is researching desalination sites, while landlocked New Mexico wants to produce drinking water by wringing salt from its brackish underground water.
    Critics say that desalination remains too expensive, in large part because of the power required to run the plants, and that the process damages the environment.
    For every two gallons of water filtered, one gallon of drinking water is produced. The highly concentrated salt water goes back to the sea. In heavy concentrations, that brine can kill small sea creatures, according to the California Coastal Commission. Scientists are still studying its effects on dolphins and other mammals.
    Supporters, however, say desalination is a crucial part of California's search for new sources of water.
    The state's population is expected to grow by 6 million by 2010. Also, earlier this month, the federal government rolled back the amount of water California can drew from the Colorado River, which is shared by six other Western states.
    "There's only so much you can conserve," said Steven Erie, political science professor and water expert at the University of California at San Diego. "The future is recycling and desalination."
    The basic process of desalination is not new. Salt water is pumped through filters under high pressure, squeezing out minerals. Israel and Kuwait have relied on desalination for decades, as have military vessels and cruise ships.
    More than a dozen small plants were built along California's coast during the early 1990s when the state faced its last drought, but most were for industry. Nearly all were shut down or dismantled because of high operating costs and because water agencies found cheaper water elsewhere.
    According to the Coastal Commission, only the city of Marina, in north-central California, still uses desalination to provide a portion of its domestic drinking water.
    But the process has become more efficient in recent years, reducing energy use and costs.
    In November, California voters approved $50 million for desalination plant construction and research. In addition to the five new plants under consideration by the MWD, eight others have been proposed along the California coast.
    Since the late 1980s, the price of taking salt out of sea water has dropped from nearly $2,000 an acre-foot to $800 per acre-foot, said Walter Winrow, vice president of Poseidon Resources. The company built the Tampa Bay project and has several proposals in Southern California.
    MWD currently sells water for nearly half that cost, but Ortega said the district would subsidize the price of desalinated water by $250 per acre-foot for the proposed plants in Carlsbad, Los Angeles, Long Beach, El Segundo and Dana Point.
    One acre-foot is enough to cover one acre, one foot deep. It typically would supply a family's needs for a year.

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