Federal officials have raised alarms about Lake Powell, a vital water storage reservoir for the Colorado River Basin, warning that water levels could drop low enough to halt hydropower generation by December 2026.
The reservoir, which is essential to the water supply for 40 million people, has seen diminishing water levels due to rising temperatures, ongoing drought conditions, and relentless water demand.
In June, officials from the Upper Basin emphasized that current conditions mirror the severe droughts of 2021 and 2022, both years when Lake Powell, along with Lake Mead, reached historic low levels.
The Upper Colorado River Commission has called for a re-evaluation of management strategies, advocating for approaches more closely aligned with annual water supply variations.
Negotiations among the seven basin states, which include Colorado, are intensifying as they seek a cooperative water management strategy after 2026.
A significant hurdle in these negotiations has been determining how to effectively cut water usage during drier years.
Commissioner Gene Shawcroft from Utah stated, “You can’t reduce what doesn’t come down the stream. And that’s the reality we’re faced with. The only way we’re going to achieve a successful outcome is if we’re willing to work together — and not just protect our own interests.”
Lake Powell, situated on the border of Utah and Arizona, serves as a catchment for water from a range of sources, including Colorado, New Mexico, Utah, Wyoming, parts of Arizona, and tribal reservations. The Glen Canyon Dam channels this water downstream to Lake Mead, tribal beneficiaries, Mexico, and the Lower Basin states, which comprise Arizona, California, and Nevada.
Together, Lake Powell and Lake Mead account for approximately 92% of the total reservoir capacity within the Colorado River Basin.
According to the Bureau of Reclamation’s July 24-month study, projections indicate that Lake Powell could dip below two critical elevations: 3,525 feet and 3,490 feet.
Emergency drought response actions would be triggered if the reservoir’s level falls below 3,525 feet as early as April 2026, based on the most probable scenario. Under drier forecasts, the reservoir could drop to this level as soon as January.
Power generation ceases when Lake Powell falls below 3,490 feet.
Recent years have seen a crisis management approach, with officials releasing water from upstream reservoirs, such as Blue Mesa—Colorado’s largest reservoir—to stabilize Lake Powell’s levels.
These emergency releases raised concerns about the recreational impact at Blue Mesa.
The findings from the July study have prompted planning for emergency releases, known as drought response operations, at both Lake Powell and other reservoirs, including Flaming Gorge, Blue Mesa, and Navajo.
Chuck Cullom, executive director of the Upper Colorado River Commission, stated in an email, “The Upper Division States and Reclamation have been monitoring the risks to Lake Powell since January 2025 due to the declining snowpack and runoff, and are prepared to take appropriate actions as conditions evolve through 2025 and spring of 2026.”
The impact on hydropower generation is a growing concern as lower water levels threaten the operational capacity of both Lake Powell and Lake Mead.
The Bureau of Reclamation has indicated that Lake Powell could descend below 3,490 feet by December 2026, while Lake Mead could fall below a pivotal elevation of 1,035 feet by May 2027.
At that juncture, Hoover Dam would be forced to shut down several turbines, significantly diminishing its power production, according to Eric Kuhn, a water expert focused on Colorado.
In more favorable or slightly wet forecasts, both reservoirs are not expected to drop below these critical thresholds in the near future.
The hydroelectric power generated by Lake Powell and other federal reservoirs provides a low-cost, reliable source of renewable energy.
Without this energy resource, electricity providers might resort to pricier energy options or nonrenewable sources, potentially leading to higher monthly utility bills for consumers.
Glen Canyon Dam’s hydropower output usually integrates with other sources to supply customers across Wyoming, Colorado, Arizona, New Mexico, Nevada, Texas, and Utah.
Regrettably, the dam’s output has already faced challenges, with fourteen of the lowest generation years occurring since the year 2000.
A robust monsoon season could help boost water levels in key reservoirs, along with an above-average snowpack in the forthcoming winter.
Kuhn cautioned, “If next year is below average, then we’re setting ourselves up for some very difficult decisions in the basin.”
This situation is further complicated by potential legal disputes arising from the Colorado River Compact.
Kuhn has alerted that if the river’s flow dips below a 10-year cumulative total of around 82.5 million acre-feet, it could ignite a legal quagmire.
In such a scenario, the Lower Basin could contend that the Upper Basin must comply with the foundational agreements by sending additional water downstream.
However, opinions diverge among Upper Basin attorneys regarding the obligations for states like Colorado to divert more water downstream.
This uncertainty is of paramount concern to users, including farmers and ranchers, who already grapple with inadequate water supplies during dry spells.
From 2017 to 2026, the 10-year cumulative flow is expected to reach approximately 83 million acre-feet.
Kuhn assessed the situation by saying, “We’re OK through 2026. But under the most probable and minimum probable forecasts, it’s almost a certainty that the flow will drop below 82.5.”
Additionally, the ecosystems of Lake Powell are now facing intensified challenges due to diminishing water levels.
US Geological Survey Research Ecologist Bridget Deemer has been closely monitoring the effects of reduced water levels on lake ecosystems.
Her recent research highlighted a concerning trend: low dissolved oxygen zones are expanding as water levels decrease, with more sediment accumulating within the reservoir over time.
This sediment accumulation may lead to higher decomposition rates, which depletes the oxygen in the water, severely affecting aquatic life.
Deemer pointed out that the premium fish habitat is particularly compromised beneath Glen Canyon Dam.
In 2023, there were 116 days when the water’s oxygen level dropped below 5 milligrams per liter—just above lethal conditions for trout, which can perish at levels between 2 and 3 milligrams per liter.
Deemer is also investigating the implications of harmful algae blooms, which were observed near Lake Powell around the Fourth of July and again last fall.
Though the causes behind these bloom events remain unclear, prior research indicates that heightened water temperatures and excessive nutrients are primary contributors.
Such blooms can pose risks to fish, humans, pets, and any organisms consuming the algae.
Despite these challenges, Deemer noted, “In general, Lake Powell is doing well. Its waters are clear with minimal nutrients and algal growth. These blooms are more localized and limited in scale.”
image source from：coloradosun
