Groundwater replenishment in the Upper Colorado River Basin – a key component of water supplies for seven Southwestern states and Mexico – may benefit from projected increases in future basin-wide precipitation under current climate warming projections, according to a recent study by the U.S. Geological Survey and Bureau of Reclamation.
The most advanced climate modeling projections predict a wetter future for the region, according to USGS, with more precipitation falling as rain as the climate warms. Groundwater resources are replenished through increases in precipitation, which may offset reductions from increased temperatures on surface water supplies.
The new paper is being viewed as a modicum of good news against the backdrop of a 15-year-drought in the basin, and widespread studies predicting a hotter, drier future for the region.
The full report is available online in the journal Geophysical Research Letters.
The scientists projected changes in groundwater recharge for the Upper Colorado River Basin from recent historical (1950–2015) through future (2016–2099) time periods using climate projections and a groundwater-recharge model, according to a USGS press release. They noted that most models show increases in groundwater recharge, while some showed less.
“You can’t manage what you don’t measure,” said Fred Tillman, lead author and USGS scientist, in the news release from USGS. “These results are the first step in understanding the quantity of groundwater we can expect in the Upper Colorado River Basin; however, further studies are needed to help more accurately forecast future groundwater availability.”
The Colorado River provides water for more than 35 million people in the United States and 3 million people in Mexico. Another recent USGS publication suggests that as much as half of the water flowing in rivers and streams in the Upper Colorado River Basin originates as groundwater.