Water Deliveries to Lake Powell Could Fall More Than 50%, Researchers Warn

0 Share Newsweek is a Trust Project member See more of our trusted coverage when you search. Prefer Newsweek on Google to see more of our trusted coverage when you search. Water deliveries from Colorado’s West Slope river basins to Lake Powell could fall by as much as 52 percent below their baseline median by midcentury, according to a recent study that examined how drought , changing snowmelt patterns and water demand may affect one of the Colorado River Basin’s most important source regions.

The study, published July 13 in Earth’s Future , focused on Colorado’s Upper Colorado, Gunnison, Yampa, White, San Juan and Dolores basins, which together provide about 70 percent of Lake Powell’s inflows in a typical year.

Lake Powell, behind Glen Canyon Dam on the Utah-Arizona border, is a critical reservoir for Colorado River operations, hydropower generation and water deliveries across the Southwest.

“Our study highlights the potential for continued drought to increasingly stress Lake Powell deliveries. This stress is important to consider for any future changes in operations,” lead author and postdoctoral researcher Sai Veena Sunkara told Newsweek . “However, drought is not the only concern. Our results also emphasize the importance of carefully evaluating how changes in future demands could help alleviate or compound how water shortages emerge across the West Slope basins.”

Researchers used large-scale exploratory modeling to test 20,000 “plausible midcentury scenarios,” representing more than 2 million simulated years, according to the paper. The scenarios included wetter and drier hydrologic futures, shifts in snowmelt timing, drought persistence and changing demands from municipal, industrial and agricultural users. Those scenarios were then run through Colorado’s StateMod water allocation model to estimate shortages across basins, districts and water-use sectors.

The study’s authors say there is “no single cause of future water shortages” and that planning should be tailored to specific basins and users rather than relying on “a single generic strategy.”

Still, the regional implications are significant. In its key points, the paper says projected deliveries to Lake Powell fall “up to 52 percent below their baseline median,” a decline the authors said could make compliance with Colorado River delivery obligations challenging. The study also found that major West Slope reservoirs could be 40 percent to 55 percent below their historical median storage levels under midcentury scenarios, reducing their ability to buffer water shortages, according to the Cornell Chronicle .

The timing of snowmelt was identified as one important factor in shortage risk. The Cornell Chronicle quoted the study’s senior author Patrick Reed explaining that snow acts as storage, so if it melts too early, less is available to offset dry periods.

The findings come as the broader Colorado River system is already under severe stress. The Bureau of Reclamation said in April that long-term drought had reduced Colorado River system storage to about 36 percent of capacity, while the lowest winter snowpack on record and record-breaking March heat had intensified basin-wide drought conditions.

Federal officials have also warned of risks to hydropower. Reclamation’s April 24-month study projected Lake Powell could fall below 3,490 feet—the minimum power pool level—by August 2026 without major intervention, “threatening water and power reliability for more than 40 million people,” the agency said.

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