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Wednesday, Oct. 29, 2008 | When Mayor Jerry Sanders talks about San Diego’s water-supply future, he occasionally drops in a plug for desalination. But Sanders, who has endorsed the proposed seawater desalination plant in Carlsbad, hasn’t been referencing that effort.

He’s talked — only generally, so far — about the possibility of San Diego turning to de-salted seawater as a new drinking water supply for the city.

In a recent interview, Sanders said the city would be “somewhat excited about another desal plant.” He’s also tossed it out as a potential alternative to a contentious City Council effort to recycle sewage as a drinking water source.

The concept has also popped up on the campaign trail. District 7 council candidates Marti Emerald and April Boling both endorsed the technology during a Tuesday debate on KPBS. “We ought to think about desal up and down the California coast,” Emerald said.

But if the Carlsbad plant, which has cleared permitting hurdles, manages to similarly overcome environmental groups’ legal challenges, the city of San Diego does not appear likely to follow suit any time soon — despite Sanders’ references. Nor do many other local water agencies.

While desalination holds promise as a drought-proof supply, it’s still an expensive water source that requires any developer to overcome significant environmental hurdles. It’s also still relatively unproven. The Carlsbad plant, proposed by Connecticut-based Poseidon Resources, would be the state’s first large-scale desalination effort and the country’s largest. Poseidon’s only other large-scale project, built in Tampa, Fla., ran behind schedule and suffered from numerous technical problems when it began operating in 2003.

In an arid region facing water uncertainties over the coming years, stripping the salt from seawater promises to provide at least a fraction of future supplies. Both of San Diego’s major supplies are yielding less water than they once did. The Colorado River is suffering from sustained drought; a judge has cut the amount of water that can be extracted from the Sacramento-San Joaquin River Delta, a step taken to keep an endangered fish from going extinct.

Other than the nine local water agencies that plan to buy water from the Carlsbad plant — it would produce enough water to supply 112,000 homes each year — it does not appear likely that more plants will be built as a stopgap solution even if the Los Angeles-based Metropolitan Water District cuts supplies next year. A 10 percent reduction is expected, which local agencies hope to achieve by encouraging conservation.

Poseidon’s desalination plant in Carlsbad is the only one planned locally for the next decade. Sanders doesn’t expect that to change until the proposed plant becomes reality. “I would doubt you’d see another public-private partnership until the one is built and we see it operating,” he said.

Jim Barrett, San Diego’s director of public utilities, said the city faces several issues that make desalination less attractive than encouraging an infrastructure fix that will address the ecological problems in the Sacramento Delta, where the populations of several fish species have dropped precipitously in recent years as Southern California has sucked more water out.

Among the challenges faced by the city of San Diego:

  • It owns little oceanfront property. “Trying to site a desal plant at Point Loma” — where the city-owned sewage treatment plant sits on the cliffs near Cabrillo National Monument — “is not going to be the easiest thing to do,” Barrett said.
  • It prefers to buy raw water — untreated drinking water — and purify it at the city’s three water treatment plants. Desalinated water is more expensive than buying raw water, a result of the high amounts of energy needed to purify seawater.

Barrett and Poseidon both said they had not been in contact with each other. Barrett said he wished the company luck with its legal challenges. Scott Maloni, Poseidon’s spokesman, joked that he would love to hear from the mayor — but hadn’t yet. “I wish he would call us,” Maloni said.

Maloni said desalination could work for the city simply because the region continues to have unmet demand for water. “There’s not a jurisdiction in San Diego that doesn’t need more water, which is why our project is so attractive countywide,” he said.

If the city ever undertakes a desalination plant, Barrett said it would likely join forces with the San Diego County Water Authority and not build one itself.

The water authority, the wholesaler that delivers water to the city of San Diego and 23 other member agencies, is currently studying the feasibility of building a desalination plant on Camp Pendleton. The $825,000 study, expected to conclude early next year, aims to identify several sites on the base that could accommodate a desalination plant at least as large as the 50-million-gallon-per-day plant Poseidon plans in Carlsbad. The authority is currently awaiting feedback on its study from the Marine Corps.

Bob Yamada, the authority’s water resources manager, said his agency would also undertake a year-long study in 2009 examining potential sites along the international border where desalination plants could be sited.

Neither effort is likely to yield a plant for eight to 10 years, Yamada said. And they’re not likely to help fill the gap posed by any potential supply cuts next year. Taking a desalination plant from concept to reality takes about a decade, he said.

“We’re in the middle of a situation we think is short term,” Yamada said. “In the long term as we develop these new water supplies, there aren’t any silver bullets. Desalination is not the silver bullet for this region. It can and will be an important part of our water supply in the near future — but there are other things that are just as important.”

Please contact Rob Davis directly at with your thoughts, ideas, personal stories or tips. Or set the tone of the debate with a letter to the editor.

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