Monday, May 25, 2009 | The country’s biggest seawater desalination plant has the permits it needs to start construction in Carlsbad. Except for pending legal challenges, the project is a go.

Next in line locally? The San Diego County Water Authority, the regional wholesaler that delivers water to local cities, is moving forward with studies to build a desalination plant at Camp Pendleton.

The authority is in the midst of completing a study of two sites on the base; its board will vote in June whether to approve $5.7 million over two years to fund an in-depth analysis and review of potential environmental impacts.

Step by step, the authority is laying the groundwork to tap the Pacific Ocean as a new water supply by 2018. It’s a key part of the authority’s strategy for reducing its reliance on imported supplies from the Los Angeles-based Metropolitan Water District and comes as the San Diego region faces restrictions on water use for the first time in two decades.

While the underlying concept is the same, there are key differences between the Camp Pendleton project and both the Carlsbad proposal and the country’s largest operating desalination plant in Tampa, Fla.

Namely cost.

Tampa turned to desalination earlier this decade, in a belabored effort that has never lived up to expectations. Price tag: $158 million. Maximum yield: Up to 25 million gallons of drinking water daily.

The same company that launched the Tampa project, Poseidon Resources Corp., is leading the push for the Carlsbad plant. Price tag: $320 million. Maximum yield: 50 million gallons of drinking water daily, enough for 112,000 homes a year.

Both of those projects’ price tags benefit from using existing intake infrastructure for sucking in seawater. In Carlsbad, Poseidon plans to use the pumps and pipes that already draw seawater into the Encina Power Station, the big power plant on Carlsbad’s coast.

The water authority’s project at Camp Pendleton would start from scratch. The authority estimates it would cost $1.25 billion to build a plant as large as Poseidon plans in Carlsbad. That price tag is about four times as much as the Carlsbad effort. The authority’s figure includes the expense of building infrastructure that would allow the plant to eventually triple in size and produce 150 million gallons of drinking water daily — enough for 336,000 homes. Building out would cost a total $1.9 billion, according to the authority’s estimates.

If it came online today, the plant’s water would be the most expensive (and most drought-proof) source in the authority’s supply portfolio. Bob Yamada, the authority’s water resources manager, estimated the plant’s cost per acre-foot at $1,700 to $2,100. By comparison, later this year, the authority will be selling water to San Diego and other local cities for about $900 per acre-foot. (An acre-foot of water is enough to cover an acre with a foot of water, or about enough to supply two households for a year.)

Yamada said the costs were on par with standalone desalination plants currently under construction in Australia.

Sydney’s $1.4 billion desalination plant will open this winter, contributing to a 33 percent increase in residents’ water bills over a four-year period. The plant will produce 66 million gallons daily, about 15 percent of the city’s water.

Michael Shames, executive director of the Utility Consumers’ Action Network, a local ratepayer advocate, said there may be compelling arguments to build the facility at Camp Pendleton if the authority waits until 2018.

“It’s not outrageous in terms of the dollar figures,” Shames said. “It’s an investment that may make sense. The cost of desalination should be going down.”

And if the price of water continues rising, desalination will look more cost-competitive. The Metropolitan Water District is hiking rates 20 percent this year, an increase that will trickle down to San Diego water bills. Metropolitan provides a majority of San Diego’s water.

Yamada said the plant’s cost was estimated on the high side, allowing for uncertainties in construction expenses. Construction wouldn’t begin before 2015, he said.

Many questions remain unanswered about the Camp Pendleton desalination plant, which would be located on one of two possible sites near the Santa Margarita River. The authority hasn’t yet committed to what size plant it wants to build. Yamada said that decision would depend on what happens with the region’s imported water supply.

The authority also hasn’t decided on the type of intake infrastructure the plant would use. Yamada said that was a high priority for future study.

Environmental groups including San Diego Coastkeeper and the Surfrider Foundation have objected to Poseidon’s use of the existing intake infrastructure in Carlsbad, pointing to its impacts on fish and larvae that get sucked into the intake pumps and chewed up. The environmental community has pointed to subsurface intakes — wells that allow water to be sucked in through the sandy ocean floor — as being superior.

Yamada said the authority planned to study the seafloor off Camp Pendleton’s coast to determine whether such an intake would be possible. That will in part depend on how sandy or rocky the surrounding geology is.

“One of the benefits of building new intake facilities — you’re not limited by the existing infrastructure,” Yamada said. “You can design an intake that significantly reduces impacts to marine life.”

Bruce Reznik, executive director of San Diego Coastkeeper, said he was pleased that the authority was at least willing to evaluate a subsurface intake.

“If the county water authority could figure out a way to do the project and not have the environmental impact — and really address the concerns we’ve raised — we would not oppose it,” Reznik said. “But even then, the region should be looking at a more holistic, comprehensive approach to our water supply, which is seriously lacking.”

But Reznik said the project isn’t an immediate priority. Local environmental groups are likely to turn their attention to Poseidon’s proposed desalination plant in Huntington Beach before they consider the Camp Pendleton project’s merits.

After Carlsbad, the Camp Pendleton effort remains the most likely desalination project in the county. Two sites that were once studied have been pushed aside: the San Onofre nuclear plant and the South Bay Power Plant, which both have existing intake infrastructure.

The authority is also in the early stages of studying potential desalination sites along the U.S.-Mexico border region and in Rosarito.

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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