Phoenix, Arizona faces not one but two water crises. About a third of the water in desert cities comes from people in distress. Colorado River. Cities will lose much of their supply in the coming years as rivers dry up and states face a crisis thanks to decades of severe drought caused by climate change. water outage.

Another third of the subway’s water comes from underground aquifers, which are also drying up.Earlier this month, the Arizona Water Department announced published a new report Assessing how much water remains in the aquifer below Phoenix. The data were alarming. The state has discovered that over the next 100 years it has allotted more groundwater to cities and farms than actually exists in the aquifer. If the Phoenix area continues to pump water at its current rate, these aquifers will be available over the next 100 years, according to the agency. The total shortfall amounted to about 5 million acre-feet, or about 1.6 trillion gallons, allowed for use for the next 100 years, and may not exist at all.

In response to these findings, the state government has just taken the following drastic steps: Restrict new housing construction in Phoenix and its suburbs, telling developers that new subdivisions can no longer rely on groundwater. To build homes in Arizona, developers usually first have to prove they have access to the homes. 100 years of water for such a house. For decades, most have met their criteria by drilling for groundwater. Now the state is trying to cut them off.

The announcement shocked the Arizona housing market and raised questions about the future of the Phoenix metropolitan area, one of the nation’s sprawling metropolitan areas. Rapidly growing metropolitan areas It has nearly 5 million inhabitants and continues to grow. Developers are already planning thousands of new homes in dozens of cities and towns in the region. While the state’s moratorium doesn’t make future growth impossible, it would be much more difficult and costly, jeopardizing the lucrative real estate business that has fueled the city’s expansion.

“Growth patterns will change,” says Sharon Megdal, professor of environmental science and director of the University of Arizona Center for Water Resources Research. “This declaration will have a disproportionate impact on the entire Phoenix metropolitan area.” That means cities and suburbs with access to river water and recycled wastewater will be able to grow for some time, but are dependent only on groundwater. Many remote cities will face severe challenges of further growth unless they invest heavily in alternative water sources. .

New construction isn’t going to stop any time soon. The moratorium on new development does not include the nearly 80,000 homes already approved by the state, and it will take years to build all of them. Over 27,000 new homes were built. Completed last year in Maricopa County, Phoenix. Even if that pace slows in the next few years, developers will likely run out of backlogs by the end of the decade.

And even if developers build every home with water reserves, that doesn’t mean the Phoenix area is actually completely devoid of groundwater. But it means real estate companies have to wrest the groundwater out of farmers’ hands. I have been using it for decades. Municipal water use in the Phoenix area surpassed agricultural water use decades ago, but agriculture still dominates water use. largest share Groundwater how to use Because many cities depend on the Colorado and Salt rivers for water. Farms accounted for about 41% of the region’s aquifer withdrawal in 2021, compared to about 38% for urban areas.

Cities and farms have long been at odds when it comes to groundwater.when in Arizona First regulated aquifer withdrawal Back in the 1980s, the state banned most new agricultural water uses, freezing the growth of the state’s coveted cotton and alfalfa industries.but the law allowed existing Even if a loophole were created for developers to continue building new subdivisions, farms could continue to pump in perpetuity.

Lawmakers expected that as Phoenix expanded, developers would buy up farmland and build buildings on it, turning water-intensive alfalfa fields into relatively water-efficient suburban streets. . Instead of focusing on new developments on existing farmland, property moguls flocked to the empty deserts far outside of Phoenix, where they mined shallow aquifers and farmers continued to grow alfalfa and cotton.At the same time, industrial activities such as mining and mining semiconductor equipment Swallowed more groundwater.

“There are so many traditional groundwater uses,” says Kathleen Ferris, senior fellow at Arizona State University’s Kill Water Policy Center and author of the state’s original groundwater law. “And then we allowed new development in the groundwater, which made the problem even worse.”

Still, state forecasts are very conservative.of groundwater analysis A paper published last week assumed that all the farms, homes and mines around Phoenix would continue to pump groundwater at the same rate for the rest of the century, which is likely not the case. Growers have abandoned thousands of acres of farmland over the last few decades as more households in the region use recycled wastewater, the demand for the aquifer is declining, and the agricultural economy deteriorates. . If these trends continue, more groundwater will be released for further development.

Phoenix area farmers pump approximately 300,000 acre feet of groundwater for irrigation each year. Even if that total is slightly reduced, it may be able to sustain additional housing development for some time. With an acre-foot supply of about 4 new homes per year, just 10 percent of Phoenix’s agricultural groundwater would allow him to feed over 100,000 new homes in his 100 years of need. That’s about the same number of homes the metropolitan area has added in the last five years.

“That’s the flaw,” said Spencer Kumps, legislative vice president of the Central Arizona Association of Home Builders, which represents major home builders. “Unmet demand [in the state’s model] It’s really a medium sized farm. Next he can eliminate this figure by only allowing growth to occur in three years. If the abolition of agriculture is recognized in the model, it will literally disappear. “

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The question is whether the state will allow developers to take advantage of that slack. At a press conference about the new data, Governor Katie Hobbs left the door open for the state to implement new modeling in the future.

“They clearly say [the model is] “It is based on assumptions and may undergo additional modeling in the future, which may change conclusions about groundwater availability,” Megdal said.

In 2019, the state identified a major groundwater shortage in the farm-heavy suburbs of Pinal County, just south of Phoenix, but a group of county stakeholders said the shortage was half the state’s announced value. We created a competitive model suggesting that it was. The state has since revised down its shortfall forecast.

“I’m looking forward to the conversation,” Kumps said.

But beyond groundwater, growth only becomes more difficult. Once developers acquire all groundwater, there will be no easy alternative water sources to sustain Phoenix’s rapid expansion. The Colorado River was supposed to provide a renewable water supply for Phoenix and Tucson, but it is more vulnerable than ever. Of all the states that depend on the Colorado River, Arizona has the lowest legal status, making it a prime target for future water outages. The river is the result of decades of compromise with neighboring California.

Lawmakers have proposed a number of other solutions to strengthen Phoenix’s water supply and the state. secured $1 billion We will explore them in the next few years.Some legislators have proposed raise the height of major dams Located on the Salt River that runs through Phoenix, it can store more water in the river’s main reservoir. Some people put all their effort into the idea. Construction of desalination plant in Mexico and pipe the treated water to the United States. Meanwhile, some cities have agreed to plans to import groundwater. A remote desert valley west of Phoenix.

While all of these solutions are theoretically viable, they are very expensive and the water supplied is likely to be more expensive than the cheap groundwater that has enabled Phoenix’s rapid growth. In other words, developers and homeowners will absorb the cost of new infrastructure. The question, Ferris said, is how much money developers are willing to spend to keep building, and at what point will construction in Phoenix cease to be profitable at all?

“None of these solutions are quick fixes, so I would like to see a conservative approach over the next 10 years,” said Ferris. “We have to learn to live within our means. The question is what it is.”

This article was originally published on Grist and https://grist.org/cities/phoenix-arizona-groundwater-shortage-development-agriculture/.

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