CARLSBAD -- A landmark desalination project gained final approval from regulators Wednesday, bringing the promise of an entirely new supply of water to San Diego County -- and perhaps one of many in water-short California.

But opposition to the plant, including legal action, continues. And the company that wants to build the $300 million plant in coastal Carlsbad still needs to raise the money.

On Wednesday, the San Diego Regional Water Quality Control board unanimously approved a permit for the plant. It had already considered the proposal twice this year.

The permit approves a plan by Poseidon Resources Corp. to reduce the plant's environmental impact on ocean life, especially young fish. It is to be situated next to the Encina Power Station.

Poseidon's six-year struggle for approval has been closely watched around the nation as a bellwether of desalination's prospects. All told, the plant has been considered at 14 hearings before various agencies.

If built, the plant would produce 50 million gallons of water a day, making it the largest in the Western Hemisphere. That represents about 9 percent of the water used in San Diego County. The cities of Carlsbad and Oceanside and seven local water agencies have contracted to buy water from the plant.

The agencies are: Valley Center Municipal Water District, Rincon del Diablo Municipal Water District, Sweetwater Authority, Rainbow Municipal Water District, Vallecitos Water District, Santa Fe Irrigation District and the Olivenhain Municipal Water District.

Construction is expected to begin by year's end, said Scott Maloni, a vice president of Poseidon, which is to build and own the plant. It is scheduled to be operational by the end of 2011.

Maloni said Poseidon has received multiple financing proposals.

"We need to wrap up the financing process, and that will allow us to start construction," he said.

The plant could serve as a template for other desalination plants on the California coast, where densely populated urban areas are increasingly straining their water supplies.

Most of the state's water travels to its population centers from drought-strained rivers and reservoirs hundreds of miles away, making the prospect of a reliable and nearly infinite water supply increasingly appealing.

Desalination of ocean water has not been done on a large scale in California. Santa Barbara built a desalination plant about 18 years ago, during a severe drought. But the drought ended before the plant could be put into service.

While desalinated water costs more than water from traditional sources, it won't cost San Diego County water users extra. Metropolitan Water District, Southern California's water wholesaler, will subsidize the water as part of a program to encourage development of other water sources.

Opponents fear precedent

However, the prospect of a string of desalination plants on California's coastline worries some environmental groups, who say such projects would do massive harm to coastal marine life.

A coalition of opponents said they would pursue three lawsuits filed against the Poseidon project. The opponents say they support desalination in principle, but that the plant is in the wrong place, a sensitive coastal area.

They also say other sources of water, such as through increased conservation and reclamation, should be pursued.

Two lawsuits are in litigation against the plant. A third was dismissed earlier this week by a San Diego Superior Court judge. That dismissal will probably be appealed, said Marco Gonzalez, an attorney representing Surfrider Foundation and the Planning and Conservation League.

In remarks made before the board voted, Gonzalez said the struggle against the project would go on, vowing to take the project to the state water quality board.

"I'll promise you this will not be the last hearing we have on this matter," he said.

Gonzalez also implied that board members may have had improper communication with Poseidon.

"Your state laws preclude you from having independent discussions with representatives of Poseidon," he said. "I suggest that before you make your decision, you go through each board member and you disclose if in fact you've received any e-mails from any individual representatives of Poseidon."

Board members denied any improper contact with Poseidon employees.

David King, vice chairman of the water quality board, said the permit had received careful consideration.

"We've beaten up this permit forwards and backwards, and everything has been thoroughly vetted," King said.

Contact staff writer Bradley J. Fikes at 760-739-6641. Read his blogs at bizblogs.nctimes.com.

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