Officials Seek to Build Test Plant to Desalinate Aquifers

Water officials are hoping to build a small desalination plant in Torrance as part of an effort to purge South Bay aquifers of saltwater intrusion and at the same time gird the region against drought.

The $3.5-million demonstration plant would filter salty ground water by reverse osmosis and produce 1.3 million gallons of drinking water a day--enough, water officials say, to supply about 2,400 households.

Being organized by the West Basin Municipal Water District with help from federal officials, the project is part of a long-range plan by the regional water agency to build 10 such facilities in the South Bay.

The effort faces hurdles--most immediately, securing a $1.5-million congressional appropriation to help build the demonstration plant. West Basin General Manager Richard Atwater expressed confidence Wednesday that, despite federal budget shortfalls, Congress will make the money available so the plant can be built by May, 1992.

“I think we have a convincing argument that with the California drought and water shortages, it’s important to develop this type of technology,” Atwater said.

Hal Furman, a Washington attorney hired by the West Basin district to lobby for the project, said: “It’ll be tough, there’s no question about it, but there’s a high degree of interest on the part of Congress for desalination. I think it’s probably a little better than a 50-50 chance.”

The plant would be built on land owned by Dominguez Water Corp. at Maple Avenue and Del Amo Boulevard. Assuming Congress makes the appropriation, the federal government would pay $1.5 million of the construction costs and regional water agencies would finance the remaining $2 million.

Dominguez Water Corp. would operate the plant, pumping the purified water to its Torrance customers. Plans for the project were developed by the U.S. Bureau of Reclamation, using a $200,000 congressional appropriation last year.

Water officials say the project would create a way to reclaim salt water that has seeped into South Bay water basins, forcing the closure of dozens of wells from Manhattan Beach to central Torrance.

Los Angeles County recently completed a $10-million project to upgrade high-pressure coastal barriers in an effort to halt further saltwater intrusion. But officials estimate that 20% of the South Bay’s water supplies are already contaminated by the briny plume, which continues to creep eastward.

“The intrusion is very close to some of our wells,” said Charles Schaich, a senior administrator with Torrance’s Water Department. “If this project proves feasible and cost-effective, it could be very important to everybody in the entire basin.”

While most of the South Bay’s water is piped in from Northern California and the Colorado River, wells in the area now account for more than 15% of the water supply, officials say. And the South Bay’s underground water sources take on particular importance during droughts, they say.

“The ground-water basin is just invaluable,” Atwater said Wednesday. “That is our drought emergency supply.”

The reverse osmosis process that would be used involves pumping water through filters at high pressure. The process would not be as costly as if seawater were involved. While brackish ground water in the South Bay’s aquifers is six times more saline than fresh water, Atwater said, it is 10 times less saline than seawater.

Filtering seawater, he said, would cost $2,000 to $2,500 per acre-foot. (An acre foot is 325,850 gallons.) By contrast, putting the brackish ground water through reverse osmosis would cost $550 an acre-foot, he said.

“The bottom line is that we could help clean up the basin and make way for more storage” in the area’s underground aquifers, said Joe DeMersseman, operations manager for Dominguez Water Co. “And it’ll be a new supply we couldn’t use in the past.”

Assuming the improved underground barriers are successful in stemming further saltwater intrusion, there would still be enough brackish water in the South Bay--600,000 acre-feet--to keep 10 desalination plants busy for at least 20 years, Atwater said. Filtering it, he said, would consume the useful lives of the plants and cost about $50 million to achieve.

Atwater acknowledged the danger of pumping the South Bay water basins so low that more salt water would be sucked in. To prevent that, he said, the pumping would be regulated by a management plan calling for replenishment of local aquifers with fresh water from outside the region and a planned South Bay water recycling project.

The plan, designed to increase the amount of usable water in local aquifers, would require court approval since the South Bay is subject to legal guidelines governing water extraction.

“We hope to have a draft report on it out in September,” Atwater said. “We’re trying to develop the best long-term management plan for the (South Bay).”

Furman, the lobbyist for the West Basin, said congressional budget panels will begin weighing whether to grant the $1.5-million federal appropriation in May. He said that although federal dollars are tight, Congress appears interested in water projects seeking new solutions to California’s water problems.

“If we were trying to build an irrigation water project or a new dam, it would be very difficult,” Furman said. “But there’s a growing recognition in Congress and elsewhere that these innovative projects are the wave of the future, particularly in Southern California.”