As the crisis on the Colorado River grows, new pressure to pump groundwater will further stress already-depleted aquifers across the Southwest, according to water managers and scientists studying the ongoing drought.
The decline of groundwater supplies along the Colorado River basin has been accelerating for decades, according to analysis by Arizona State University’s Jay Famiglietti. Most of those losses have come in Arizona.
“We have to be exceptionally careful because it took tens of thousands of years to accumulate, we’re burning through it on a century time scale,” Famiglietti said. “There is essentially no hope of high-magnitude replenishment.”
Because water is heavy, satellites in space can detect the diminished gravitational pull of the water when it’s removed from the ground, he said.
The added stress on groundwater comes at a time when the supply of surface water is also in decline. The Colorado River, which supplies nearly 40 million people in the West with water, has been teetering on the brink of collapse because of overuse and climate change. A drought fueled by climate change has punished the region for decades.
The seven states that rely on the river are deadlocked over negotiations to share the supply of water, and the federal government is likely to step in and demand significant cuts to their allocations by the end of the summer.
Meanwhile, political fights are escalating in places like Utah, New Mexico and Arizona over the rise of data centers and their impact on water supplies.
“We’re going to come under a lot of pressure as these Colorado River allocations get cut back,” Famiglietti said. “We will have difficult decisions on the horizon.”
Pumping mostly unregulated
In 1980, Arizona passed a groundwater-management law in response to overdrafting from the state’s aquifers. It helps protect water supplies in certain areas, including in big cities like Phoenix and Tucson.
In recent years, those protections have been expanded several times. However, according to Famiglietti’s calculations, only 18% of the state is covered.
In the sprawling suburbs around Phoenix, the Salt River Project utility recharges the aquifer by pumping water from the river over large spreading basins. The water seeps through the sand and gravel soils near the river channel and reaches the aquifer about 200 feet underground.
“Imagine your savings account at your bank,” said SRP’s Sharon Morris, who manages the utility’s groundwater storage system. “In our case, we’re saving it for a not-so-rainy day.”
Morris said SRP has banked about one million acre feet of groundwater at that basin since 1994, which is nearly the equivalent of a large upstream reservoir on the Salt River. The water can be pumped and sent to cities when it’s needed.
“Imagine what groundwater levels would be if we didn’t have that savings account,” Morris said. “They would be in far worse shape.”
Moving groundwater to thirsty cities
In areas of the state where groundwater is not regulated, the aquifers are not as healthy.
In Wenden, Ariz., about two hours outside of Phoenix, the water table has dropped 18 feet in the past two years, said Gary Saiter, chairman of the Wenden Domestic Water Improvement District.
“It’s steadily gone down over the years, and it’s because of overfarming,” Saiter said.
This desert town is flanked by agriculture. For years, nearby farms have grown crops like pistachios and alfalfa and pumped groundwater without much regard for the aquifer.
The state filed a lawsuit against a Saudi-owned farm operating in La Paz County, alleging it used excessive groundwater to grow alfalfa.
In Wenden, there are signs that the ground is sinking as a result of pumping the aquifer.
Saiter’s wife, DaVona Saiter, owns the Mas Paz Desert Spirit gift shop, where the floors of her 125-year-old building are slanting downward. Gaps of several inches between the floor and the wall have emerged. A large crack has appeared on the front patio.
“That’s absolutely terrifying to think you can have this natural body — I call it nature’s perfection — that we have altered it to where it is no longer useful,” said DaVona Saiter, referring to the lowered aquifer.
The Saiters have been fighting to stop a bill at the Arizona legislature that would allow private entities to pump water from the McMullan Valley aquifer and sell it to cities like Phoenix and Tucson, arguing it would put the town at further risk for the benefit of major population centers and large corporate landowners.
“I don’t think most of the people in the legislature really care about rural Arizona,” Gary Saiter said.
However, supporters of the groundwater transfer say cities need the water to attract new development and housing, especially because the supply of Colorado River water is likely to face steep cuts.
“If nothing happens, then things continue to get worse,” said Stan Barnes, a lobbyist for Water Asset Management, a New York hedge fund that owns large tracts of farmland in the area.
Barnes told lawmakers earlier this year that the bill would protect the aquifer because it would put a cap on how much groundwater could be pumped. He also said his client was moving away from growing water-intensive crops like alfalfa.
“You can demagogue the New York hedge fund because it feels good. But that’s not what this is about,” Barnes said.
The debate over transferring groundwater from rural areas to cities epitomizes the mounting pressures caused by the persistent drought.
The bill in Arizona would allow pumping of the McMullan Valley aquifer down to 1,200 feet. Rob McDermott’s 600-foot wells at the Morenga Palms RV Park that he runs outside of Wenden went dry a few years ago. He paid $120,000 to dig a new well to 800 feet, and he cannot afford to do it again.
“They’ll just pump this place until it dries up and blows away,” he said.
This article was originally published on WBUR.org.
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