U.S. Water News Online
PHOENIX — Arizona officials are studying the possibility of importing treated ocean water from a popular coastal Mexican resort 60 miles south of the border.
The move would help sustain urban supplies in Arizona by bringing potentially billions of gallons of water to the state a year and could someday bring relief to rural residents, who have long sought a water source to replace rapidly depleting aquifers.
A Scottsdale company already is looking at possible designs for a desalination plant in Puerto Penasco in the Mexican state of Sonora. Overworked groundwater wells there are on the verge of running dry.
Arizona water managers see an opening for the state to team up with the seaside resort on a larger plant to serve both countries.
“Desalinated ocean water is the future sustainable source,” said Herb Guenther, director of the Arizona Department of Water Resources. “It's only logical that eventually we'll migrate toward it. We don't need interim supplies now. We need a permanent supply.”
The project would raise political, economic, and environmental issues, and it's unclear who would pay construction costs that could top $250 billion. But if those hurdles are cleared, Arizona and neighboring states could tap a plentiful supply of water largely immune to the effects of drought and climate change.
Only recently has the ocean emerged as a viable resource in the United States. At least two dozen plants are now on drawing boards in California, a state beset with water woes.
“People explored and utilized the most cost-effective sources of water as long as they could,” said Randy Truby, past president and a current director of the International Desalination Association, an industry group. “In California, they had the state water project, the Colorado River, sewage-water reclaim, conservation ... but once you exhaust all of those things, seawater desalting is about the only place you can go.”
That's the situation in Puerto Penasco, also known as Rocky Point. The city's groundwater resources have dwindled after years of steady use. The wells produce poor-quality water, and many are nearly exhausted. With growing interest from American developers, the city decided to turn to the ocean.
“The water needs are severe,” said Walt Bouchard, whose Scottsdale-based environmental consulting company was hired to study desalination options for Puerto Penasco. “There are concerns that water may not be available for future development.”
Puerto Penasco officials asked The Bouchard Companies to determine the feasibility of a seawater desalination plant, settle on a technology, produce a blueprint and prepare a bid package for a company that would design, build and operate the plant.
The study is based on a desalination plant that would produce 11.4 million gallons a day at the start and up to 45.6 million gallons a day by 2020, when the final stage is completed. That's enough water to serve at least 250,000 people a year.
Mayor Heriberto Renteria put the Puerto Penasco project on a fast track, with a goal of firing up the first desalination module by 2010 or 2011. Bouchard said his team expects to deliver its findings by the end of the year.
The plan so far calls for a plant that would produce water for the local and tourist demand, but Bouchard said the city is aware of Arizona's interest and could consider a joint project once Puerto Penasco's needs are met.
“Could they supply water to Arizona? The answer to that is very likely yes,” Bouchard said. “We believe it is feasible. The question becomes what about the cost of conveyance? Could it work for Arizona? As part of the state's overall water portfolio, it might have a place.”
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