NASA scientist, using satellite tracking, raises warning about our water’s future

More than 2 billion people rely on groundwater for drinking water, but space-based technology is finding trouble under the earth’s surface.

Hydrologist Jay Famiglietti leads a team that uses satellites to measure groundwater in aquifers around the globe. He will speak at “America’s Water: An Uncertain Future” on Dec. 1 in Charlotte. The event, part of The Charlotte Observer and Bank of America “Our Times Re-Imagined” series, is sold out.

Famiglietti is a professor at the University of California, Irvine, and senior water scientist at the NASA Jet Propulsion Laboratory in Pasadena. He likens NASA’s Gravity Recovery and Climate Experiment technology to “a scale in the sky.”

Two satellites track each other closely as they orbit. The presence of water, below on Earth, exerts a tiny gravitational tug on one satellite that the other detects. Using that data, researchers can map the world to show where water is massing or receding.

The news isn’t good. Aquifers in the driest parts of the world – he includes the High Plains and the Central Valley of California – are being drained.

Famiglietti blames poor monitoring and regulation of groundwater, which is used disproportionately by property owners rich enough to tap it. Around the world, he says, groundwater is unsustainably used in agriculture and as a buffer against drought.

“The irony of groundwater is that despite its critical importance to global water supplies, it attracts insufficient management attention relative to more visible surface water supplies in rivers and reservoirs,” he wrote last year in the journal Nature Climate Change.

The Southeast is water-rich compared to the arid West, but both regions share a frustrating lack of detailed knowledge about groundwater reserves, Famiglietti said in an interview.

California, in its fourth year of drought, now gets 75 percent of its drinking water from groundwater but doesn’t know how much water is in its aquifers, he said. North Carolina regulates groundwater withdrawals only within a 15-county region of the coastal plain where aquifers have been overpumped.

Famiglietti says groundwater resources should be explored in as much detail as oil reserves. Groundwater and surface water such as rivers should also be managed together, he says, and withdrawals for both reported.

“It’s like having money in the bank – it’s good to know how much is there before you start bouncing checks,” he said.

“What does it take to get people to do that longer term planning? How do you plan for 20, 30 or 40 years from now, (when) I think the big issue for the Southeast is that the southern half of the country is getting dryer?”

Climate change models show the southern United States growing dryer and the North getting wetter in coming decades. Rainfall in the Catawba River basin, including Charlotte, has already dropped 10 percent in the past 50 years.

“We will have haves and have-nots,” Famiglietti said. That, in turn, will demand regional and national solutions.

Like climate change, he said, groundwater depletion can’t be reversed.

“This ship is long gone,” Famiglietti said. “There’s no help for minimizing anything. It’s all about managing our way through now.”

This story was originally published November 27, 2015 at 1:00 AM with the headline "NASA scientist, using satellite tracking, raises warning about our water’s future."