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The groundwater is like a big retirement account. And that’s all we have. And some people are using more than others—some are draining it. So, we really need to think about future generations.
Jay Famiglietti, director of science for the Arizona Water Innovation Initiative
Last week, news broke that the depletion of groundwater across the Colorado River Basin has been quietly, rapidly outpacing the more visible decline of the river itself. Even as the seven basin states negotiate reduced consumption of river water—inevitably driving dependence toward local aquifers instead—this newly published research shows that most of the water lost throughout the basin in recent years has been underground. In the Lower Colorado River Basin alone, groundwater has accounted for 71% of total water supply loss.
Jay Famiglietti, a longtime contributor to Ten Across, specializes in the use of satellite data to monitor the world’s groundwater mass. His team’s new findings focus on the U.S. Southwest—a region at the forefront of the nation’s water supply challenges and the complex balances between resource limitations and economic growth.
As states and cities in the Colorado River Basin and elsewhere develop water management strategies to sustain themselves through future constraints, a growing understanding of groundwater supply is key to effective proactive policy. It is increasingly clear that time is of the essence for this uniquely finite resource.
Listen in as Ten Across founder Duke Reiter and Jay Famiglietti discuss the concrete findings in this report, the immediate and long-term implications for agriculture in the Southwest, and Jay’s motivations for raising awareness of groundwater usage in the Ten Across region and beyond.
Relevant articles and resources:
Read The Washington Post’s analysis
More analysis from The Guardian and Inside Climate News
Catch up on the Colorado River negotiations
Listen to Jay’s first podcast appearance
Related headlines:
“ADWR Director Briefs UA Water Resources Research Center Conference on Colorado River Negotiations” (azwater.gov, June 2025)
“It’s not just big alfalfa farms. La Paz residents fear groundwater grab by big cities” (Arizona Republic, June 2025)
“Arizona wants this city to cut its groundwater use. Residents want flexibility” (Arizona Republic, May 2025)
“Even in wet years, wells are still dry. Why replenishing California’s groundwater is painfully slow” (Cal Matters, February 2025)
“Opinion: Will We Have to Pump the Great Lakes to California to Feed the Nation?” (The New York Times, August 2024)
Credits:
Host: Duke Reiter
Producer and editor: Taylor Griffith
Music by: Lupus Nocte and Tellsonic
Research and support provided by: Kate Carefoot, Rae Ulrich, and Sabine Butler
Guest Speaker
Jay Famiglietti is a Global Futures professor at Arizona State University’s School of Sustainability, director of science for the Arizona Water Innovation Initiative, and associated faculty in the School of Sustainable Engineering and the Built Environment and the Swette Center for Sustainable Food Systems. Previously, Jay was executive director of the Global Institute for Water Security at the University of Saskatchewan and a senior water scientist at the NASA Jet Propulsion Laboratory at the California Institute of Technology. He has served on the California State Water Boards in the Santa Ana and Los Angeles regions.
