ASU research touches on Arizona groundwater management

ASU professor Jay Famiglietti and his research team are helping to monitor groundwater storage changes across the state, find new groundwater, maintain it at a level that will ensure longevity, and fend off overexploitation.

For more than a quarter-century, Famiglietti and his team have been working on a satellite system he said can track groundwater supply changes and depletion from space via the NASA GRACE mission. He said his research can help Arizona protect and identify vital groundwater supply and divulge how to better utilize it for future generations.

The satellite system functions more as a scale instead of a camera or thermometer, meaning that when there are heavy water losses, the satellite falls closer into Earth’s orbit, Famiglietti said. NASA makes incredibly accurate measurements based on the positions of the scales.

There are two satellites orbiting around the poles, and they cannot find groundwater.

“As the Earth is spinning around and the satellites are moving, they’re basically sweeping over the Earth mapping these places. They’re gaining or losing water storage on a monthly basis and longer so we can start looking at trends over 20 years,” Famiglietti said.

While the absolute amount of groundwater cannot be tracked, the satellite system can track the rate at which groundwater levels are changing around the world.

Concerning Arizona’s water supply, Famiglietti said, “Like a lot of the American Southwest, it’s very dry. We’re losing a fair amount of water here across the state. Something like between one and one and a half million acre feet per year. A lot of that is because of things like climate change, the fact that the Colorado River Basin is drying out and we don’t get as much streamflow, and the fact that we use a lot of groundwater,” Famiglietti said.

In the future, Famiglietti and his team can use the satellites to understand past trends that show how water storage is changing, as well as using observations on the ground to understand how much water is truly needed statewide.

Famiglietti also hosts a popular podcast on Apple, now being produced by Arizona PBS, called “What About Water.”