Floyd Dominy, the commissioner of the federal Bureau of Reclamation during the 1960s, bore significant responsibility for the construction of Glen Canyon Dam on the Colorado River. Upon the dam’s completion in 1963, the profound impacts of a changing climate, including diminished snowpack, record-breaking temperatures, and persistently low water levels in Lake Powell, were likely beyond his foresight. However, the design choices made by Dominy and his engineering teams—specifically, the limited operational flexibility built into the dam’s infrastructure—failed to adequately anticipate a potential water supply crisis that has now materialized.

For decades, a crisis has been steadily escalating along the Colorado River, marked by contentious disputes among various stakeholders over the allocation of its rapidly dwindling flows. This situation has recently entered a critical and precarious phase. A significant deadline loomed on November 11th: the seven states dependent on the river—California, Arizona, Nevada, Utah, New Mexico, Colorado, and Wyoming—were tasked with agreeing upon a new management plan. Failure to do so would have necessitated the federal government imposing its own plan, an outcome none of the states desired. Concurrently, the thirty Native American tribes with water rights along the river have historically been, and continue to be, excluded from these vital negotiations.

That November deadline passed without resolution, and the federal government ultimately deferred action, extending the decision-making period to February 14th. This postponement was met with little surprise, as the history of Colorado River management is replete with unmet deadlines and unfulfilled ultimatums. Despite decades of declining reservoir levels and clear scientific warnings about the accelerating impacts of global warming and prolonged drought, significant hand-wringing and a smattering of temporary conservation measures have yielded minimal progress toward permanent changes in water usage across the Colorado River Basin.

For years, the seven Basin states have operated under the assumption that they could draw more water than the river naturally supplies, by tapping into reserves accumulated in Lake Mead and Lake Powell during the exceptionally wet decades of the 1980s and 1990s. These water entitlements were established based on an inflated estimate of river flows from 1922, when the Colorado River Compact was drafted, rendering the "paper" water rights largely a theoretical construct and a persistent source of conflict. This water savings account has now been depleted, with both Lake Mead and Lake Powell hovering below 30% capacity, and their levels continuing a steady downward trajectory. Climate change has exacerbated this decline; in the 21st century alone, the river’s flow has decreased by 20% compared to its long-term annual averages, with scientific projections indicating a continued reduction as global temperatures rise.

Compounding these issues, the physical infrastructure responsible for managing the Colorado River’s water is nearing a point of potential catastrophic failure. The Bureau of Reclamation has offered only a minimal acknowledgment of this looming threat, with a brief mention in a technical memorandum released in 2024. The shrinking water levels in Lake Powell, a reservoir created by Glen Canyon Dam, are exposing deeper, systemic problems within the dam itself. The 710-foot-tall dam was engineered for a more stable hydrological environment, a stark contrast to the Colorado River’s well-documented historical variability, characterized by extreme floods and prolonged droughts. Nevertheless, the Bureau, imbued with a Cold War-era confidence, or perhaps hubris, downplayed these risks. During the record-breaking El Niño winter of 1983, the dam narrowly avoided overtopping due to a combination of mismanagement and design limitations, specifically insufficient spillway capacity for major flood events. Only the temporary installation of plywood across its crest and cooler temperatures that slowed snowmelt prevented a potential disaster.

Today, the dam faces a threat not from excess water, but from its profound scarcity. In March 2023, Lake Powell’s water level dropped to within 30 feet of the minimum threshold required for power generation, a level known as "minimum power pool." At an elevation of 3,490 feet above sea level, this point is only 20 feet above the actual intake points for the dam’s eight turbines, known as penstocks. To prevent cavitation—a phenomenon where air is drawn into the penstocks, creating explosive bubbles that can severely damage the dam’s internal components—the turbines must be shut down at minimum power pool.

The consequences of reaching minimum power pool are even more concerning. Once the penstocks are closed, the only remaining method for releasing water through the dam is via the river outlet works (ROWs). These consist of two intakes situated on the rear face of the dam, feeding into four 96-inch-diameter steel pipes with a combined maximum discharge capacity of 15,000 cubic feet per second. However, these bypass tubes suffer from a critical design flaw: they are not safe for prolonged use and are prone to erosion when reservoir levels are low.

During a high-flow release into the Grand Canyon in 2023, conducted under low-reservoir conditions, damaging cavitation was observed within the ROWs. The Bureau has warned that extended use would likely lead to further cavitation. In practical terms, the safe release of water downstream may be significantly less than the stated capacity, and the onset of cavitation could necessitate a complete cessation of flows. Such a scenario would directly compromise the dam’s ability to meet its legal downstream delivery obligations, potentially leaving the 25 million people who rely on the river for drinking water, as well as the multi-billion dollar agricultural sector, without sufficient supply. This precarious situation indicates that Lake Powell, and by extension the entire Colorado River system, is perilously close to operational collapse.

Should reservoir levels fall to the ROWs’ elevation of 3,370 feet above sea level, Lake Powell would reach "dead pool." At this point, water would only pass through the dam when the river’s inflow exceeded the amount lost to evaporation from the reservoir’s surface. No other intakes or spillways exist below the ROWs, meaning there is effectively no "drain plug." Notably, there remains a substantial volume of water—approximately 1.7 million acre-feet—trapped within the dam’s structure, down to the original riverbed, which would become stagnant, warm, and susceptible to algal blooms and anoxic conditions. The lake’s shape, resembling a martini glass in its vertical cross-section, would cause water levels to fluctuate dramatically, potentially by as much as 100 feet in a single season.

An insufficient or complete lack of water flow through Glen Canyon Dam would precipitate a disaster of unprecedented scale. It would profoundly impact major population centers, some of the world’s most significant economies, and the delicate ecosystems that depend on the river’s flow all the way to the Gulf of California in Mexico. The Lower Basin states—California, Arizona, and Nevada—voiced these concerns in a recent letter to Interior Secretary Doug Burgum, asserting that the Bureau’s failure to address the dam’s plumbing deficiencies in its current environmental impact statement for post-2026 operations violates federal law. The letter emphasized that "Addressing the infrastructure limitations may be the one long-term measure that would best achieve operation and management improvements to the Glen Canyon Dam." To date, the Bureau has not issued a formal response.

It is increasingly evident that Glen Canyon Dam requires modification to meet its operational and legal mandates. This process must also consider the ecological health of the river system, both upstream in Glen Canyon and downstream in the Grand Canyon. The most effective strategy to avert operational failure and the ensuing economic and ecological catastrophes involves re-engineering the dam to allow the river to flow through or around it at its natural level, thereby enabling the transport of sediment into the Grand Canyon.

Significantly, Floyd Dominy himself proposed a conceptually simple and elegant solution. In 1997, the former commissioner sketched on a cocktail napkin a plan involving new bypass tunnels to be excavated through the surrounding soft sandstone. These tunnels would be equipped with waterproof valves to regulate the passage of both water and sediment. This proposal essentially calls for a comprehensive intervention, akin to open-heart surgery, to restore the health of the Colorado River, which is currently critically endangered. Dominy’s napkin sketch, signed and presented to Richard Ingebretsen, the founder of the Glen Canyon Institute, serves as a foundational blueprint for a more sustainable future for the Colorado River and the human and natural communities that depend upon it.

However, the timeframe to implement such a solution and avert dead pool is alarmingly short and rapidly diminishing, particularly given the extensive study, design, and construction phases required for a project of this magnitude. The erosion of federal agency expertise and capacity during recent administrations further amplifies the urgency of this issue. Regardless of the decisions made on February 14th, federal authorities and the Basin states must move beyond water disputes and focus on establishing a resilient and sustainable future for the Colorado River.