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Controversial Billion-Dollar Desalination Plant to Provide San Diego County With 'Drought-Proof' Water Supply

The final piece of the Carlsbad Desalination Project's 10-mile water pipeline was installed last week, a monumental step in the process of building the largest desalination plant in the Western Hemisphere.

The plant will serve the San Diego County Water Authority in 2016, providing 50 million gallons of water per day to as many as 300,000 San Diegans.

However, it doesn't come without a price; the facility is estimated to cost $1 billion upon completion.

The county has turned to desalination as California continues to battle its fourth-consecutive year of drought, but some environmentalists worry it may not be worth the cost, neither economically nor environmentally.

The plant will draw in seawater from the ocean where it's processed through a reverse osmosis system, filtering out salt and other impurities.

A portion of the processed sea water will then become high-quality fresh water distributed throughout San Diego County. The rest of the water will be used to dilute the filtered salt before returning to the ocean as concentrated seawater.

What effect this will have on marine life is up for debate.

According to a 2013 study by the University of California, Davis, "The high salt concentrations reduce oxygen levels in the water causing the plants and wildlife in the area to suffer."

But Poseidon, the plant's operator, attests, "Seawater desalination plants that are properly sited and utilize the best available design and technology can effectively minimize or avoid significant marine life effects."

The salt byproduct will not harm sea life, Poseidon's Community Outreach Manager Jessica Jones told AccuWeather. However, upon intake, larvae will be pulled into the plant with water, amounting to about a pound and a half of fish per day, or the daily diet of one brown pelican.

"We're mitigating for that by restoring wetlands in San Diego County, 66-acres of wetlands," Jones said.

The company was named one of the United States' Top 100 Companies that are Going Green and considers the project to be one of the most technologically advanced, energy efficient and environmentally sensitive in the world.

Regardless, to mitigate its footprint, Poseidon has also agreed to assume responsibility for maintaining and dredging the 388-acre Agua Hedionda Lagoon, which sits adjacent to the facility.

It was previously maintained by the Encina Power Station, which is expected to be decommissioned in the years to come.

Aside from its environmental impacts, experts say the process of desalination is undoubtedly more expensive than traditional methods. But, desalination costs are rapidly falling as technology improves.

When the plant goes online, the cost of water per month will go up about $5-7 per household.

"Years ago, desalination was much more expensive than it is today. Desalination has come a very long way and so it's much more feasible," Jones said.

"And as far as the cost, we're able to offset a lot of the energy costs by using energy recovery devices and solar panels and other cost-saving measures throughout the plant so that it becomes more economical."

Though it's the first desalination plant to hit San Diego's shores, it's far from the first in the state.

Several localities either considered or built desalination facilities along the California Coast amid periods of extended drought in the 1980s, according to the California Department of Water Resources.

Santa Barbara's Charles E. Meyer Desalination Plant was one of them. The plant operated from March to June of 1992 before abundant rainfall ended the drought in subsequent winters.

The county is now considering bringing it back online.

Additionally, more than a dozen more desalination facilities are in the planning stages along the California coast, with one facility in late-stage development in Huntington Beach.

"I wouldn't say that desal is a complete game changer," Jones said. "I think that new water supplies are a game changer in California. Desal is just part of the pie, part of the puzzle, also looking at reclamation and conservation and all the other new, local, reliable sources of water."

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