A new study from researchers at Princeton University, in collaboration with the University of Arizona, has produced the most detailed map yet of groundwater depth across the continental United States. The map estimates how deep groundwater sits beneath the surface with greater accuracy, with detail down to areas about 100 feet across.
That marks a major shift from previous groundwater maps, which often relied on less specific regional or county-level averages. By using machine learning and a wide range of environmental data, the researchers were able to estimate groundwater depth in places where direct measurements are sparse or unavailable.
“You always think the closest water is like a lake or a river or stream, but the closest water is beneath your feet,” said Reed Maxwell, a Princeton engineer and co-author of the study. “That as an education outreach component is really important, particularly in the West, where it’s so out of sight, out of mind.”
When the data is applied to the Mountain West and Southwest, it reveals sharp differences over short distances — areas with relatively shallow groundwater sitting close to places where water is much deeper and harder to access. Researchers say that kind of variability is especially important in arid regions where groundwater plays a central role in water supply during drought.
The researchers say the publicly available map could help water managers better understand local groundwater conditions, plan for drought, and avoid over-pumping already stressed aquifers, especially as climate change drives hotter temperatures and more variable precipitation across the West.
This story was produced by the Mountain West News Bureau, a collaboration between KUNR, Wyoming Public Media, Nevada Public Radio, Boise State Public Radio in Idaho, KUNC in Northern Colorado, KANW in New Mexico, Colorado Public Radio, KJZZ in Arizona and NPR, with additional support from affiliate newsrooms across the region. Funding for the Mountain West News Bureau is provided in part by the Corporation for Public Broadcasting and Eric and Wendy Schmidt.
