The University of Colorado says a study in press in AGU's Water Resources Research concludes that through 2026, "the risk of fully depleting reservoir storage in any given year remains below 10% under any scenario of climate fluctuation or management alternative. During this period, the reservoir storage could even recover from its current low level, according to the authors." [right, Lake Powell. Credit, Bureau of Reclamation]
"But if climate change results in a 10% reduction in the Colorado River's average stream flow as some recent studies predict, the chances of fully depleting reservoir storage will exceed 25% by 2057, according to the study. If climate change results in a 20% reduction, the chances of fully depleting reservoir storage will exceed 50% by 2057.""Total storage capacity of reservoirs on the Colorado exceeds 60 million acre feet, almost 4 times the average annual flow on the river, and the two largest reservoirs -- Lake Mead and Lake Powell -- can store up to 50 million acre feet of water. As a result, the risk of full reservoir depletion will remain low through 2026, even with a 20 percent stream flow reduction induced by climate change."
Ref: "Water Supply Risk on the Colorado River: Can Management Mitigate?"