Drought, population growth combine to make costly use of seawater a more viable alternative. CALIFORNIA: DESALINATION
PARCHED by four years of drought - and with forecasts of more to come - California is turning to seawater to help quench its growing thirst. The state's average influx of 600,000 new residents a year over the 1980s has accelerated the depletion of many communities' already-tenuous freshwater supplies. Over the same period, various technologies have been developed and improved - helping make seawater a viable alternative to conventional sources. Thus, many communities are not just seeking to alleviate the current drought by turning saline water into fresh. They are investigating desalination as at least a minor contributor, and perhaps a major one, to solving long-term water problems.
First plant opened
San Nicolas Island (off the coast between Los Angeles and San Diego) opened the state's first major desalination plant on Oct. 11, generating 12,000 gallons of drinking water a day from the ocean. A second plant will open this year, enabling the 27-square-mile island to seal its groundwater wells and get all its water from the ocean.
The Marin [County] Municipal Water District currently operates a pilot desalination plant near the north end of San Francisco Bay. Although the bay is less salty than the ocean, it is more clouded with silt from rivers, industrial waste, and microscopic marine life. The plant is experimenting with various types of pre-treatment filtration systems to clean bay water before it goes into the desalination plant. The district hopes to raise $55 million to $65 million to build its own desalting plant and is developing a proposal for voters by November 1991.
Santa Barbara is months away from building a $25 million plant to supply one-third of the city's needs by 1992. Pending city approval, Ionics Inc., a company headquartered in Watertown, Mass., will build, own, and operate the plant to supply water to the city for five to 10 years. Perhaps hardest hit by the drought, Santa Barbara's main water source - the Cachuma Reservoir - is at 15 percent capacity. Its secondary source, Gibraltar Reservoir, is empty.