The Colorado River, which allows the desert to sustain itself and powers millions of American homes, is currently engaged in the fight of its life. The rapidly sinking river—victim of a nearly 23-year-long megadrought—stretches 1,450 miles, snaking its way from Colorado through Arizona, Nevada, and California, and finally into Mexico, where it should theoretically dump out into the Sea of Cortez. But the water rarely gets that far, thanks to a series of dams and agricultural canals that have devastated the natural river as well as the Mexican communities that once depended on it. In the U.S., meanwhile, 40 million Americans rely on the river as a source of water and power, without many viable alternatives.
This crisis has made clear the fragility of water resources in the Southwest, but it has also demonstrated that hydropower cannot be the reliable clean energy solution that many would like to write it off as. Throughout the U.S., drought, extreme heat, flooding, and many other factors are complicating efforts to use green power methods. Our clean energy sources have to adapt to climate change even as we hope they might help us avert its worst effects. More stable sources are increasingly urgent.
America’s two largest dams by volume are both situated along the Colorado River. The Hoover Dam at Lake Mead and the Glen Canyon Dam at Lake Powell provide power for approximately 4 million Americans in the seven basin states. Dams have what is called a dead-pool level, which is the depth at which water will no longer flow downstream, as well as a minimum power-pool elevation, which is the depth at which the turbines in a dam can no longer produce power.* The Hoover and Glen Canyon dams are both owned and operated by the U.S. Bureau of Reclamation, and they have been in operation since 1936 and 1966, respectively. The merits and ethics of hydropower are hotly debated: While dams can create a large amount of energy without relying on fossil fuels, they also damage ecosystems and often significantly reduce the biodiversity of the body of water on which they sit. Dams also tend to be built on Native American land, and Indigenous communities disproportionately shoulder the negative effects of these structures. Despite these concerns, hydropower makes up almost one-third of renewable energy production in America—and for more than 4 million people, the health of the Colorado River dams are a direct link to their energy security.
Lake Mead currently sits only 152 feet above its dead-pool level and 97 feet above its power-pool level, meaning the Hoover Dam is on the edge of becoming a relic of a time when water was a reliable energy resource. Lake Powell, meanwhile, is 152 feet away from dead-pool and just 32 feet away from power-pool. Projections for when these dams will hit the minimum power-pool elevation, barring significant changes to water usage and drought conditions, are far from comforting: A prediction by the U.S. Bureau of Reclamation shows that we likely have until about 2025.*
The drama surrounding the Colorado River has reached a crescendo in national news over the past several months as the states have struggled to work out a mitigation plan. On Aug. 16, the Biden administration announced the first ever Tier 2 water shortage for the Colorado River, meaning that basin states would have to reduce their water usage by 2 to 4 million acre-feet in the coming year. This happened after the states missed their first deadline to present a plan to cut usage, on Aug. 15, and the federal government made Jan. 31 the final deadline. This time, two rival plans were presented: one from California and one from a coalition of Arizona, Colorado, New Mexico, Nevada, Utah, and Wyoming. Next, the federal government will evaluate the merits of the plans—but at this point, lacking a cohesive strategy from the basin states to handle the crisis without outside assistance, the federal government is within its right to take over the situation.
Dam managers, meanwhile, have begun to take preventative measures to try to reduce the amount of water loss. An intake system installed at the Glen Canyon Dam in mid-January will allow for an extra 8 feet of elevation loss before the water stops running to the neighboring communities. There is also a proposal for a $46 million project to rejig the pipes inside the dam that could make waterflow consistent for longer under the drought projections, but this is a temporary—and expensive—fix. A 2015 report found that if the Glen Canyon Dam shut off, the power rates for residential customers would only rise by about 8 cents a month, but that figure has likely risen due to utility cost increases nationwide. In December, the Washington Post reported that cities like Page, Arizona, depend on low-cost power from the Glen Canyon Dam, which costs around $30 per megawatt hour, compared to up to $1,000 on the open market. The Navajo Tribal Utility Authority gets approximately 40 percent of its energy from the river, and without it, would need a massive amount of reorganization to shift off of hydropower.
As the water crisis along the Colorado River continues, Americans in the basin states will need to adjust to living with less water at their disposal. A 2019 study found that dams in America could be replaced by solar panels using just 13 percent of the space. Nuclear power is highly efficient (if controversial), and is the second-largest source of low-carbon power in the world (after hydropower). But so far, there have been few efforts to find replacements for the energy currently being produced by drought-unstable dams in the U.S. A 2022 study found that hydropower systems around global coastlines will be most vulnerable to climate-induced changes. In the letter accompanying their recent mitigation proposal, the six states with a unified plan stated that even under dry conditions, where significant compromises are needed, maintaining both Lake Mead and Lake Powell above dead-pool and power-pool levels—and thus preserving their ability to generate power—is a top priority.*
But for now, as hydropower becomes more unstable, reliance on dirty energy production methods is rising in its place. Policy such as the Inflation Reduction Act has created tax credits and incentives for using renewable energy sources like hydropower, but it will not be enough investment to maintain the integrity of the aging structures while also adapting to changing environmental conditions. There is never going to be a perfect solution to mitigate the impacts of the lowering water level, but drastic measures to reduce reliance on water and to keep power plants running—while also expanding renewable energy alternatives like solar—will be the most effective path forward. The sooner states can lower their water usage, the better chance the Colorado River and its dams will have at a sustainable future.
The U.S is far from the only country dealing with the rise of unstable hydropower. Climate change has ravaged hydropower in China, southeast Brazil, and Spain. As Lake Mead and Lake Powell are showing, the U.S. may be heading for a similar fate: The ability to power large swaths of the country is literally evaporating into thin air. Hydropower is too integrated into the green energy grid to lose, and time is running out to keep the country’s water, and power, flowing.
Future Tense is a partnership of Slate, New America, and Arizona State University that examines emerging technologies, public policy, and society.
Correction, Feb. 15, 2023: This piece originally erroneously conflated dead-pool level with minimum power-pool elevation. Dead-pool level is the level at which water will no longer flow downstream, whereas minimum power-pool elevation is the depth below which a dam can no longer produce power. Minimum power-pool elevation is higher than dead-pool level. The piece also originally misstated Lake Mead’s distance from dead-pool level. It is 152 feet away, not 52 feet. The piece has been updated to include the power-pool and dead-pool levels for both dams.