Lake Mead, the largest reservoir in the United States, has plummeted to its lowest water level since it was filled some 90 years ago, the latest sign of a deepening water crisis in the American west.
Water levels at the reservoir, which straddles the Arizona-Nevada border outside Las Vegas, hit 1,040.4ft (317.1 meters) above sea level on Friday, according to federal data. That’s just below the record set on 28 July 2022, according to the US Bureau of Reclamation.
Critical water source for millions
The reservoir is a critical storage system on the Colorado River, a massive waterway that supplies roughly 40 million people across seven US states, tribal nations and Mexico, and irrigates millions of acres of farmland.
But the Colorado River basin is facing enormous pressure due to a combination of overuse, prolonged drought and extreme heat, and a lack of snowmelt to replenish the river. Lake Powell, the second major reservoir on the Colorado River, is also at historic low levels.
“It’s extremely significant and extremely concerning. You have three-quarters of the population of the Colorado River basin, some 30 million people, who are directly impacted by risks to Lake Mead,” said JB Hamby, the chair of the Colorado River board of California and a board member of the Imperial Irrigation District, the largest user of the river’s water. Hamby said it is vital for states that use Colorado River water to reduce water use.
Drought and depleted snowpack
Drought and dry conditions have stretched along the length of the Colorado and are particularly intense at its source in the Rocky Mountains. Melting snow provides important water for the river. This past winter, however, saw the worst snowpack on record for the Colorado River basin, adding more stress on farmers, industry, wildlife and hydropower producers, as well as the cities and towns that rely on the waterway.
Years of overuse combined with drought and rising temperatures have been depleting Lake Mead and Lake Powell, the country’s second-largest reservoir. Both are the lowest they have been in nearly seven decades.
Efforts to protect the system
To protect the strained system’s ability to produce hydropower, federal officials said Thursday that they will not release cool Lake Powell water from Glen Canyon Dam in northern Arizona to protect a threatened native fish, the humpback chub, whose habitat is between the reservoirs.
Federal officials recently announced a short-term proposal to stave off a crisis in the beleaguered waterway, after states that rely on it – California, Colorado, Arizona, Nevada, New Mexico, Wyoming and Utah – failed to reach an agreement on how to share the dwindling resource in the long term.
The federal proposal called for the Lower Basin states of Arizona, California and Nevada to take less water. The Bureau of Reclamation, which released the plan, said it was flexible: deeper cuts could happen in drier times, while states would have more time to collectively agree on how to manage the scarce resources.
Impacts and future outlook
The government is expected to release a so-called “record of decision” in the coming weeks offering more details on the plan, but experts have warned it might not be enough to solve the problems facing the imperiled river.
Severe drought in 2022 on Lake Mead, which is held back by Hoover Dam, exposed human remains and forced water officials in Las Vegas to pump water from deeper within the reservoir to continue to supply water to millions of people. Levels at Lake Powell have dropped so much that it has become difficult to descend far enough to reach the water. Boat ramps have had to move, shut down or be built anew.
Lake Mead and Lake Powell are not alone. Of the 54 western reservoirs tracked by the federal Bureau of Reclamation, nine recently recorded their lowest levels in the last three decades. Federal officials do not believe the record will stay where it is. According to modeling done in July, Lake Mead is forecast to continue dropping through much of the rest of the year.
