Meanwhile, On The Colorado - Worst-Case Outcome Has Mead And Powell At 9% Of Their Combined Capacity In Less Than 1 Year

Consumption of Colorado River water is outpacing nature’s ability to replenish it, with the basin’s reservoirs on the verge of being depleted to the point of exhaustion without urgent federal action to cut use, according to a new analysis from leading experts of the river.

The analysis, published Thursday, found that if the river’s water continues to be used at the same rate and the Southwest sees another winter as dry as the last one, Lakes Mead and Powell—the nation’s two largest reservoirs—would collectively hold 9 percent of the water they can store by the end of next summer. After enduring decades of overconsumption of the river’s water, the lakes would have just under 4 million acre feet of water in storage for emergencies and drier years when demand can’t be met. Every year, roughly 13 million acre feet is taken from the river for drinking water and human development across the region, with conservative forecasts estimating roughly 9.3 million acre feet of inflow next year.

The report is stark in its assessment of the situation: Current Colorado River levels require “immediate and substantial reductions in consumptive use across the Basin” or Lake Powell by 2027 would have no storage left and “would have to be operated as a ‘run of river” facility” in which only the inflow from the river could be released downstream. “The River recognizes no human laws or governance structures and follows only physical ones,” the report’s authors wrote. “There is a declining amount of water available in the Colorado River system, primarily caused by the effects of a warming climate—longer growing seasons, drier soils, and less efficient conversion of the winter snowpack into stream flow. Although American society has developed infrastructure to store the spring snowmelt and make that water available in other seasons to more completely utilize the variable runoff, the Colorado River watershed produces only a finite volume of water, regardless of how many dams exist.”

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Adding to the issue is the status of the infrastructure that enables the river to be diverted and stored for use. For example, the researchers write, it was thought that anything above what’s known as “dead pool”—a water level below the reservoirs’ lowest outlets that can pass water through the dams—was “active storage.” But testing last year from the Bureau of Reclamation, the federal agency overseeing the river and its dams, found that those outlets can only be safely used at water levels higher than previously thought and cannot be used for long durations. Margaret Garcia, an associate professor at ASU’s School of Sustainable Engineering and the Built Environment, who was not a part of the study, said the analyses makes clear the “reality of dead pool is within sight” for the basin’s reservoirs, even without considering the possibility of having an extremely dry year.

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https://insideclimatenews.org/news/15092025/colorado-river-reservoir-consumption/

Ed. - FYI, Powell is currently at 28.16% of total capacity of 24,322,000 acre-feet. Mead is currently at 31.67% of total capacity of 25,877,000.

Original capacity of the two reservoirs was 27,000,000 acre-feet and 32,000,000 acre-feet, respectively. The missing 8.8 million acre-feet are all the space in the reservoirs now occupied by silt and mud instead of water.

With the 2025 runoff season months in the past, storage will decline until April or May of 2026, with Colorado basin snowpack dictating next year's outcomes.

https://lakepowell.water-data.com/