"The Colorado River Basin has lost twice as much groundwater since 2003 as water taken out of its reservoirs, according to a study based on satellite data."
"The dwindling flow of the Colorado River has alarmed the American West for years, but the water losses happening underground are even worse, according to a new study that uses satellite data to measure groundwater supplies across the Colorado River Basin.
The research found that the region lost 27.8 million acre-feet of groundwater since 2003, roughly the same volume as the total capacity of Lake Mead — the nation’s largest reservoir — and that the decline accelerated rapidly over the past decade. These groundwater losses accounted for more than twice the amount taken out of reservoirs in the region during that time.
“The picture of what’s happening is pretty dire,” said Jay Famiglietti, a professor at Arizona State University and the senior author on the study, published Tuesday in the journal Geophysical Research Letters.
Famiglietti and colleagues based their findings on NASA satellite data that can measure Earth’s gravity field to estimate the mass of water underground and how that changes over time. They used data from other sensors to isolate groundwater from estimates of snowpack, surface water and moisture in the soil."
Joshua Partlow reports for the Washington Post May 27, 2025.
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