Arizona's water supply, barring unlikely and extreme weather events, should get us through the next 30 to 50 years.

After that, as our December feature article on the subject pointed out, water will be in short supply sometime this century. The reason isn't global warming or reduced Colorado River flow -- it's the millions of people expected to move to Arizona. If they don't come, there will be plenty of water (though maybe not much of an economy).

So what's the solution to this sustainability problem?

To several state leaders, it's desalination.

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As our article "Apocalypse No" explained -- with the help of the most recent data and interviews with experts -- Arizona's water problems aren't as bad as you've been led to believe by some environmentalist writers and climatologists. We showed how the extreme scenarios painted by some climate-change experts were exaggerations.

But the article also explained how, a few decades from now, the addition of an anticipated 3 million new residents means the demand for water (at current usage rates) eventually will outstrip the supply.

The problem is an economic and cultural one, primarily: The state long has relied on growth for its economic happiness, and it continues to rely on growth. At the same time, 70 percent of the state's water supply is used by agriculture. Suffice it to say that many reasons exist for not wanting to divert too much of that water to residential and business use.

With those problems and limitations -- some in our control, some not -- Arizona will need a major new water supply in 30-plus years if it's to go on the same way it always has.

The Arizona Department of Water Resources, coincidentally, published a major report in January that backed up our feature article's conclusions. Some local leaders have made comments in the press about the issue since then, the most recent one on Wednesday in the Arizona Republic by Chad Heinrich, vice president of public affairs and economic development for the Greater Phoenix Chamber of Commerce.

Heinrich wrote:

Arizona will need to innovate when it comes to developing new water supplies and conserving the water we already have. Water-policy leaders are researching options for both of these efforts. These include resolving ongoing water-rights claims through adjudication, promoting water conservation, continuing sustainable groundwater use, reusing reclaimed water and evaluating the importation of desalinated ocean water.

The last point -- desalination -- is the biggie. It's the only thing Heinrich mentions that would provide a new water source. Officials from the Department of Water Resources officials, Salt River Project and Phil Gordon, former mayor for Phoenix, have also suggested desal as a large-scale solution. Arizona would partner with Mexico in the proposals, drawing seawater from the Gulf of California.

Failing to plan for the incoming horde of new residents "would be putting our future in jeopardy," Heinrich tells New Times. "We can't rest on our laurels and say, 'best case is maybe they won't show.'"

While desal plants are expensive, need a lot of energy, and produce pollution in the form of concentrated "waste brine," which requires proper disposal, they provide a ready technological answer to the water-supply problem.

In the face of drought and climate change in the 21st century's second half, Arizona might be able to use the technology to prop up its economy, which is based primarily on strong, continued population growth.

That brings up the other side of this dual-edged sword of desal: More growth means more land development and less desert, which is bad for the environment. If an economy based on growth is allowed to go on unabated 30 years from now because of water supplies from a massive desal plant, at what point does the state deal with its reliance on growth for its economy? After the second or third major desal plant and another 10 million new residents?

The latest push for desalination as a way to water the state (the idea goes back at least to the 1960s) "ignores the message on conservation," says Sandy Bahr, director of the Sierra Club's Grand Canyon Chapter. "It encourages people to continue business as usual."

Business-minded leaders in the state are trying to sustain the unsustainable, and "failing to recognize that there really are limits," she says.

Pointing out that environmental sustainability is more important than short-term economic gains, Bahr's solution to the problem of too many Arizonans involves curbing the "massive sprawl developments" and letting other states grow water-intensive crops like alfalfa. People need to adopt a new culture of conservation and diversify the economy in Arizona, Bahr insists. Yet she agrees few signs exist of those things even beginning to occur right now. One possible example is the "Conserve to Enhance" program, which encourages residential users to save water, then apply the savings from their water bill to suggested charitable uses, like riparian restoration projects.

Conservation won't be crucial, on the other hand, if a desal plant provides enough relatively inexpensive water to meet the state's growth needs. But is keeping up Arizona's economic debauchery into the 22nd century actually a good thing? The best to be said for such a scenario, probably, is that it beats the alternative.

In theory, desal could allow Arizonans to avoid substantial cuts in water supplies for various other users, like farmers. But most experts believe desal is not a "silver bullet" to fix the future water shortage, mainly because of its high cost, says Dave White, co-director of the Decision Center for a Desert City at Arizona State University.

The smartest solution lies in a diversified portfolio of "less expensive and less challenging options" that will be deployed long before pricey desal, he says. The "suite" of water-management proposals includes negotiating with farmers for some of their water, "grand bargains" with other states or Mexico over existing water rights, and re-using wastewater with greater efficiency.

But if those solutions still leave the state short, the ocean will provide all of Arizona's needs and then some -- for a price.

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