With other sources of drinking water drying up, water districts from Los Angeles to San Diego are hoping to build desalination plants to tap the vast resources of the ocean.
Straining the salt from the seawater has long been a dream in drought-prone and fast-growing Southern California. But the costs have always been prohibitive. Now, a new generation of super-fine filters has sharply cut the expense of purifying saltwater, so much so that five local water agencies hope to build plants that would create a supply for more than a million people.
"Ultimately, it is the future of Southern California," said Steven Erie, director of the Urban Studies and Planning Program at UC San Diego. "No water, and there's no great Southern California civilization or economy. It's pretty simple. That's why they call it 'liquid gold.' "
Desalination, expensive and energy-consuming, has long been a popular water source in the oil-rich nations of the Middle East. During desperate droughts, a handful of California cities, such as Santa Barbara, built expensive plants but quickly mothballed them because of the cost.
Advances in filtration technology over the past decade have drastically reduced the price of desalinated water, though it is still about four times more expensive than groundwater. However, population growth and reduced water from the Colorado River means Californians are thirsty for new sources. Some scientists predict a drought in California and reductions in mountain snowpacks that provide drinking water, making the supply even tighter.
Southern California water officials are embarking on plans to make sewage water clean enough to drink and are even talking about floating bags of river water from Northern California. Scenarios like those make desalinated water look a lot more palatable.
About three years ago, the Metropolitan Water District of Southern California started encouraging local districts to make the move and formulated a plan to subsidize some projects.
"There was a growing sentiment that perhaps desalination could be feasible," said Adan Ortega Jr., MWD's vice president for external affairs. "The heart of the strategy for Southern California's long-term reliability ... is not to put all of our eggs in the proverbial basket. What we need to do is spread our dependence among a variety of resources so that in the event of a prolonged drought, we have more options already in place."
Around the world, 13,600 desalination plants produce 6.8 billion gallons of water daily, according to U.S. Water News Online, a trade publication. California water officials know of no major seawater desalination plants currently operating in this country, aside from a few tiny facilities on Catalina Island, the Monterey Bay Aquarium and the visitors center of a state park at San Simeon.
Desalination of briny groundwater is relatively common; the Orange County Water District does it to get rid of the minerals from dairy cow waste that contaminate groundwater.
Santa Barbara opened a $34-million seawater desalination plant in 1992 but shut it after three months because of the expense. Eventually, parts of the plant were sold off to other countries. The city keeps the facility in "long-term storage mode," and will be forced to spend $3 million to reactivate it if a new water supply is needed. Morro Bay also built a desalination facility during the drought of the early 1990s but has not used it since 1995.
Despite those setbacks, the idea of desalination is making a strong comeback.
The nation's largest seawater desalination plant currently is being built on the east side of Tampa Bay. The plant became necessary even though Florida is engorged with water because so much of the region's groundwater was being consumed that fragile ecosystems were being dramatically altered. Ponds were disappearing, and swamps were drying up. The $108-million project will create 25 million gallons of drinking water a day--10% of the local supply--when it opens in December and a second plant is under consideration, said Don Lindeman, project manager at Tampa Bay Water.
Last April in Texas, Gov. Rick Perry asked the Texas Water Development Board to study the viability of seawater desalination. In California, hundreds of millions of dollars will be available for desalination projects if voters in November approve Proposition 50, a $3.4-billion water-quality bond measure.
Assemblyman Bob Hertzberg (D-Van Nuys) has proposed the creation of a state task force to assess seawater desalination throughout California. Though his bill unanimously passed the Assembly, it has stalled in the Senate because of its $600,000 price tag.
In Southern California, MWD is reviewing proposals to build plants in Dana Point, Carlsbad in San Diego County and several coastal locations in Los Angeles County. This fall, the agency will decide whether to subsidize some or all of these plants.
