Colorado River might recover from two-decade drought thanks to precipitation

The American Southwest and its drinking water may not be in as bad of shape as originally thought. A new study coming from researchers at CU Boulder, reveals that precipitation, not temperature, will keep the Colorado River fuller than previous research told us.

The Journal of Climate published the study Tuesday as a guide for policymakers, water managers, states and tribes to figure out how to monitor the river until 2050. New guidelines are going to replace regulations from 2007, which are set to expire at the end of 2026.  

Comprehensive climate model analysis from CIRES, an institute of the University of Colorado Boulder, forecasting precipitation for the next 25 years, shows a 70% chance of increased precipitation compared with the last two decades, which brought the Colorado River to a devastating drought. 

"The temperature is warming, but that's not the full story -- you add precipitation and you get a fuller picture," says Balaji Rajagopalan, co-author of the study.

Researchers studied Lee's Ferry flows, which are the dividing point of the Colorado's upper and lower basins, and where many tourists typically launch boats into the Grand Canyon. 

"We find it is more likely than not that Lee Ferry flows will be greater during 2026-2050 than since 2000 as a consequence of a more favorable precipitation cycle," says Martin Hoerling, the paper's lead author. "This will compensate the negative effects of more warming in the near term. There's roughly a 4% chance that Lee Ferry flows could decline another 20% in the next quarter century compared to the last 20 years." 

Colorado River headwaters originate as snow in Colorado and Wyoming mountains above 10,000 feet and supplies water to 40 million people in seven states and parts of Mexico.  

Scientists have regarded 15 million acre feet of water as a key figure in measuring Colorado River flows. They've garnered that the river has had extreme wet and dry periods throughout the last century starting in 1895. Since the 2000 megadrought, the river has produced around 12.5 million acre feet each year. Arizona, California and Nevada have agreed to save three million acre feet ahead of the 2026 deadline.