A Thirsty County Is Rethinking Desalination : Water: With the persistent drought, officials consider the process a potentially viable source of supplies. But it would be expensive.

Only a year ago, desalting seawater to help solve Ventura County’s drought problems was considered a luxury that few communities could afford.

When the subject came up at public meetings, desalination was often summarily dismissed as too expensive to be practical. Leaders looked instead to water from Northern California via the state’s aqueduct, a dam on the Sespe Creek or treated waste water as additional sources.

But the continuing drought has proved that the state’s water supply is less reliable and more expensive than previously believed. Even as the Metropolitan Water District, the county’s supplier of state water, cut supplies by 30%, it raised prices by more than 20%.

The Sespe Creek in the county’s rugged backcountry is still the subject of proposed legislation that would prohibit building a dam, and drinking treated waste water is still unappealing to most.

Increasingly, water leaders in Ventura County are looking for solutions from the sea--or from previously useless brackish underground supplies. Seawater and salty ground water can be transformed into drinking water through a process called reverse osmosis.

Water made potable by reverse osmosis, an energy-intensive process in which water is forced through a salt-filtering membrane, is now considered a potentially viable supplement to existing supplies for areas that include Simi Valley, Thousand Oaks, Oxnard, Port Hueneme and Ventura.

“Desalination is expensive, but it’s a whole lot cheaper than no water at all,” said Lowell Preston, the county’s manager of water resources. “We have to have 100% assurance that we have water in the future.”

Preston is consultant to a group of water leaders and city representatives called together by Supervisor John Flynn to discuss development of a regional desalination plant.

“It has needed a catalyst to get going,” Preston said. “That catalyst is me.”

The cost to desalinate seawater, including construction and maintenance expenses, is estimated at about $2,000 an acre-foot. An acre-foot is enough water to supply the needs of two families of four for one year, experts say.

The estimated cost of desalinating brackish underground water ranges from $600 to $1,000 an acre-foot. Water imported from the state through MWD and delivered by the Calleguas Municipal Water District now costs nearly $350 an acre-foot for those agencies already hooked up to the state supply. Those that must build new pipelines to access the water would pay about $1,000 an acre-foot.

Ground water is still the cheapest by far, at less than $100 an acre-foot including the cost of energy to pump, well maintenance and drilling. But cities and farmers that pump water from the ground have to cut back 25% over the next 18 years to prevent seawater from contaminating supplies.

A regional desalination plant to supplement overtaxed supplies to coastal communities is only one approach considered in the county.

The city of Ventura is independently studying desalination of seawater and brackish ground water. The Calleguas district is looking at desalination as a means to convert the salty ground water in the inland areas of the Las Posas and Simi valleys into drinking water.

And the tiny Channel Islands Beach Community Services District, which provides municipal services to the unincorporated Hollywood Beach area in west Oxnard, may be furthest along in the planning process. The district is studying whether to build a plant to serve its 13,000 constituents, or whether to work toward a joint project with the city of Port Hueneme and the nearby Navy base.

“We feel we will go ahead with it,” board Vice President James A. Antonioli said of a desalination plant.

But some in Ventura County worry that the newfound support for desalination could undo all the work that has been done toward securing other supplemental supplies.

“There is the perception on the part of the masses that the alternatives are mutually exclusive,” said Rex Laird, executive director of the Ventura County Farm Bureau and a member of Flynn’s committee.

“I am deeply troubled over the dialogue I’ve witnessed on whether desalination or importation of state water is best . . . because in all probability, they will both be necessary.”

Laird said that instead of arguing over the merits of each solution, the projects should be ranked according to cost and how quickly the systems could begin producing. Then, the sources should be developed one by one.

“In agriculture, we have a lot to lose by the ineptness of the cities and governments in providing adequate water supplies because we know they will come after our ground water when they run out,” Laird said.

In addition, there are unanswered questions on the effects that desalination plants could have on the ocean environment, said Mark Capelli, coastal program analyst for the California Coastal Commission.

“There just aren’t many people experienced with large-scale desal plants on the West Coast, so it’s more a matter of our collective inexperience,” he said.

Public funds to construct the plants, whose costs are estimated at $25 million to $215 million, have also been considered an obstacle.

But Preston, the county’s water resources manager, said a private-public partnership--similar to one that has built a plant for the city of Santa Barbara with little or no public outlay--could be that answer.

“We don’t have to use public funds,” he said.

The debate over the best supplemental water supply in Ventura County has intensified as the state is clutched in the sixth year of drought.

Although Ventura County rainfall was normal for the 1991 rainy season and is near-normal so far this year, rainfall statewide is only 60% of average.

And it is Northern California rainfall that feeds the state’s aqueduct and supplements drinking and agriculture water to 475,000 people in Ventura County.

The lack of sufficient rainfall forced the state to cut deliveries and guarantee only 20% of the water that was requested from it this year.

The MWD, which supplements its state water with supplies from the Colorado River, passed along many of the cuts.

Through Calleguas and the MWD, the cities of Simi Valley, Thousand Oaks, Moorpark, Oxnard and Camarillo, along with growers in nearby unincorporated areas, are hooked up to the state aqueduct. But last year, those cities’ allocations were reduced by 20% and agriculture users were cut by 50% for an overall reduction of 30%.

The state is now looking for the best site for a new reservoir to increase storage so that it can be better prepared for the next drought cycle, state officials said. But it will still be saddled with a growing population and growing demand.

“The amount of water we can get is limited,” said James Hubert, manager of the Calleguas district. “The state looks like it will never deliver all that was contracted for. We have to look at developing alternate sources of water.”

But Maurice Roos, chief hydrologist for the state Department of Water Resources that operates the aqueduct, said his department’s water is still the best bargain. Building a new reservoir would only increase costs by about 10%, he said. And the bulk of the state’s massive water storage and pumping system is already in place.

“Our system has the (financial) advantage of having been built when things were cheaper,” he said. “With desal, you’re still looking at something that is eight times more expensive. Things like energy and construction costs that could affect the cost of state water will also affect the cost of building desalination plants.”

John Johnson, general manager of the Casitas Water District, which serves 55,000 people in the Ojai Valley and the western part of Ventura, said the state has been a stable long-term supplier.

“It took five years of drought before there were any cutbacks,” he said.

He and his district are not ready to buy into desalination as a solution.

“It takes a tremendous amount of power to operate a desalination plant,” he said. “There are issues about power shortages in the future. And if prices go through the ceiling, desal costs would go up much faster than the cost of state water.”

Casitas is leading a joint search with Ventura and the United Water Conservation District in the Santa Clara River Valley to find the cheapest way to connect to the state’s aqueduct system at Castaic Lake near the intersection of Interstate 5 and California 126.

At one time, the issue of whether to construct a $90-million pipeline to Castaic consumed most of the debate over supplemental water supplies in the western half of the county. Casitas is still pursuing the pipeline idea, but it is no longer considered the total solution.

“In the past, we’ve talked about state water and desalination being mutually exclusive,” said Shelley Jones, director of public works for Ventura. “But now, I think we’re looking at a combination of things.”

Jones said studies that will shape Ventura’s master plan for water will be finished in June.

Oxnard is among the parties interested in a regional plant, said Joseph Yurko, the city’s general services director.

“It’s a proven technology,” he said. “You just throw some money at it, and out comes water to drink.”

The city is also studying how it can reclaim some of the 20,000 acre-feet of treated waste water that it discharges into the ocean annually. It has commissioned preliminary engineering studies that focus on further treating waste water to make it usable for crops.

Through reverse osmosis, waste water could be sufficiently treated to be used for drinking, he said.

“But we wouldn’t desalinate the treated water because no one wants to drink their own reclamation,” said Yurko, who has worked on city water issues for 19 years. “I think we need both desalination and reclamation.”

Gerard W. Kapuscik, general manager of the Channel Islands district, predicted that his district will be the first in the county to have a desalination plant up and running, although the earliest possible completion date for a plant is still two years away and the board of directors has not yet voted on the issue.

Kapuscik and others also have predicted that the cost of state water will increase dramatically by the year 2000, from the current $350 to about $1,000 per acre-foot and that demand will continue to outstrip supply.

Desalinating water, whether from underground or the sea, will provide a constant supply that is dependent neither on rainfall nor on outside agencies, he said.

“We will have stable water prices when others relying on imported supplies will more than likely have increasing prices and unreliable supplies,” he said.

Roger Martin, project manager for Ionics Inc., which is building the nation’s largest municipal desalination plant in Santa Barbara, said Ventura County’s coastal and inland cities are prime potential clients for desalination. In addition, he said the cost of desalination does not have to be prohibitive.

Operating costs account for about half the total $2,000-per-acre-foot cost, Martin said, with the cost to build the plant accounting for the balance. But he said the $24-million to $28-million construction costs are spread out over five years. If the plant were paid off over 20 years instead, the per-acre-foot cost would be reduced to $1,200 he said.

The company, whose stock is traded on the New York Stock Exchange, built the plant with its own funds and will operate under contract to the city.

“Ionics is contemplating offering to same thing to Ventura County,” Martin said. “We could do seawater desalination and treat brackish well water and not have to run the 70 miles of pipeline from Lake Castaic,” he said.

Seawater Desalination Plant

1) Sea water is pumped into the plant.

2) Water is forced through a series of filters that strain out silt and large particles.

3) The filtered water is pumped at high pressure through a series of membranes. The water molecules are forced through the membranes, while the salts stay behind. About 4.5 gallons out of every 10 gallons becomes drinking water.

4) The remaining 5.5 gallons of salty water are piped back to the ocean.

5) The pure water is chloriniated to kill bacteria and pumped into the drinking water.

SOURCE: Southern California Edison Co.