Parched Colorado River Basin is Using Up Underground Water Supply

It turns out that the drought-stricken Colorado River Basin may just be losing its water from underground resources. Scientists have found that more than 75 percent of water loss comes from these groundwater sources.

The Colorado River Basin has been suffering from prolonged, severe drought since 2000. In fact, it's experienced the driest 14-year period in the last hundred years. That's why scientists decided to take a closer look in order to quantify the amount that groundwater contributes to the water needs of the western states.

The scientists used data from NASA's Gravity Recovery and Climate Experiment (GRACE) satellite mission in order to track the changes in the mass of the Colorado River Basin. In the end, they found that monthly measurements in water mass from December 2004 to November 2013 revealed the basin lost nearly 53 million acre feet.

"We don't know exactly how much groundwater we have left, so we don't know when we're going to run out," said Stephanie Castle, a water resources specialist at UC Irvine, in a news release. "This is a lot of water to lose. We thought that the picture could be pretty bad, but this was shocking."

In fact, the Colorado River is the only major river in the southwest part of the United States. The water supplies about 40 million people in seven states, as well as irrigating about four million acres of farmland.

"The Colorado River Basin is the water lifeline of the western United States," said Jay Famiglietti, senior author. "With Lake Mead at its lowest level ever, we wanted to explore whether the basin, like most other regions around the world, was relying on groundwater to make up for the limited surface-water supply. We found a surprisingly high and long-term reliance on groundwater to bridge the gap between supply and demand."

The findings reveal the fact that the drought could be a huge issue not just now, but also in the future.

The findings are published in the journal Geophysical Research Letters.