In Arizona’s Willcox Basin, just over an hour east of Tucson, the ground is sinking, wells are drying up, and deep cracks are splitting the earth.
Some low-lying areas even flood after rain, despite the region’s desert climate. The reason, scientists say, is simple: too much groundwater is being pumped for agriculture.
“For a long time, there were no water regulations there,” explains Dr. Danielle Smilovsky, a geospatial scientist at the Conrad Blucher Institute.
Her new research, presented at the 2025 Geological Society of America (GSA) meeting in San Antonio, reveals just how bad the problem has become.
Using satellite data collected between 2017 and 2021, Smilovsky found that some parts of the Willcox Basin are sinking by as much as six inches each year—nearly three feet in total over the study period.
In some areas, the ground has dropped up to 12 feet since the 1950s.
This phenomenon, known as land subsidence, occurs when more groundwater is pumped out than nature can replace.
Normally, the water stored underground helps hold up the surrounding soil and rock—like a cushion supporting the ground above. But as water levels fall, the empty spaces between soil grains collapse, and the land surface sinks.
“Once those pores collapse, they can’t be reopened,” says Brian Conway, a geophysicist with the Arizona Department of Water Resources. “Even if water returns to the aquifer, that storage space is gone forever.”
In an arid region like southern Arizona, losing underground water storage makes managing limited water supplies even harder.
During the wet winter of 2022–2023, heavy rainfall and mountain snow gave residents hope that natural recharge might slow the sinking. But the following hot, dry summer erased most of those gains. Smilovsky’s research showed that while subsidence slowed slightly, it did not stop.
Still, there may be some relief ahead.
In 2024, Arizona officials declared the Willcox Basin an Active Management Area (AMA)—a designation that allows stricter control over groundwater use. A similar policy has already helped reduce or even halt land subsidence in Phoenix and Tucson.
“Groundwater levels are recovering in those areas,” says Conway. “We’ve seen sinking rates decrease dramatically, and in some places, it’s stopped altogether.”
However, experts caution that the damage already done in Willcox is irreversible. The land that has compacted cannot expand again, and the lost aquifer space is gone for good.
“It needs to not be a desert with such high water demand to truly recover,” says Smilovsky. “I don’t think subsidence will ever completely stop—but with careful management, we might be able to slow it down.”
Source: KSR.
