Imagine a landscape where the ground beneath your feet is literally disappearing. That's the stark reality in Arizona's Willcox Basin, just an hour's drive east of Tucson. Here, the earth is cracking open, wells are drying up, and rain floods areas that should stay dry. It's a dramatic scene, and it's all because of one thing: excessive groundwater extraction.
Large-scale agriculture, reliant on pumping vast amounts of groundwater for irrigation, is the culprit. As the water table drops, the land itself is sinking—a process called subsidence. Dr. Danielle Smilovsky, a geospatial research scientist at the Conrad Blucher Institute, points out a critical issue: "For a long time, there were no water regulations in place."
But here's where it gets controversial: In a groundbreaking study presented at GSA Connects 2025 in San Antonio, Texas, Smilovsky revealed alarming findings. Using satellite data, she tracked subsidence in the Willcox Basin from 2017 to 2021. Some areas sank as much as six inches per year, totaling nearly three feet over the study period. Since the 1950s, parts of the basin have dropped by a staggering 12 feet. While the Willcox Basin is currently the fastest-sinking area in Arizona, subsidence is a statewide problem.
So, what causes this sinking? It happens when groundwater is pumped out faster than it can be replenished. As the water levels drop, the spaces between sediment grains—normally filled with water—begin to collapse. Brian Conway, a geophysicist at the Arizona Department of Water Resources, explains, "Those pore spaces, once held open by water pressure, start to close, causing the surface above to sink due to compaction."
And this is the part most people miss: The compaction is permanent. Even if groundwater levels rise again, the storage capacity of the aquifer is lost forever. In a desert environment, where every drop of water counts, this loss makes sustainable water use even more challenging. Fissures and flooding are just the visible symptoms; the real issue is the irreversible damage to the aquifer.
In the winter of 2022–2023, heavy rainfall and snowpack offered a glimmer of hope. Officials and residents hoped the groundwater would recharge, slowing the subsidence. However, Smilovsky's research showed that the hot, dry summer that followed erased most of these gains. While subsidence rates temporarily slowed, it wasn’t enough to stop the sinking.
There is, however, a potential solution. Policymakers can designate the region as an Active Management Area (AMA), a tool that has successfully slowed subsidence in other Arizona basins. After a failed ballot initiative in 2022, the Willcox Basin was finally declared an AMA this year. While the specifics are still being worked out, AMAs have proven effective in places like Phoenix and Tucson. Conway notes, "Groundwater levels are recovering, and subsidence rates have decreased significantly. In Tucson, we’re no longer seeing subsidence thanks to groundwater management."
But here’s the harsh reality: The damage already done in the Willcox Basin is irreversible. Smilovsky warns, "It would need to stop being a desert—with far less demand for groundwater—to significantly recover water levels. I don’t think subsidence will ever stop, but an AMA might slow it down."
This raises a critical question: Can we balance agricultural needs with sustainable water use? Or is the Willcox Basin a cautionary tale of what happens when we push natural resources to their limits? Let us know your thoughts in the comments—this is a conversation we all need to have.
