The United States’ largest reservoir, Lake Mead, has reached its lowest level on record as the drought-stricken West faces a growing water crisis.

The giant reservoir created by the Hoover Dam on the Colorado River outside Las Vegas dropped to a record-low elevation Aug. 7, reaching 1,040.5 feet. The lake provides water for tens of millions of American homes, businesses and farmers, along with carbon-free hydroelectricity.

The lake level has fallen every day since July 31, according to data from the Bureau of Reclamation. Elevation levels in the lake have been tracked since officials first began filling the reservoir in the 1930s. The lake hit its previous modern record-low level of 1,040.58 feet on July 28, 2022, before several wetter winters helped refill it. 

“It’s grim and we obviously need to do something – and fast,” said Brad Udall, a senior climate scientist at Colorado State University’s Colorado Water Center.

The last time Lake Mead was near this low, in 2022, Sen. Mark Kelly, D-Ariz., warned of “drastic consequences for Arizona and other Colorado Basin states.” If levels at key reservoirs drop further, consequences could include the loss of hydropower generation and even “dead pool” conditions, in which no water would flow out of Lake Mead.

In 2022, low water levels in Lake Mead revealed sunken boats, the remains of towns that were submerged to make the reservoir, and several bodies.

Lake Mead is the source of drinking water for about 25 million people, of a total of about 40 million served by the Colorado River Basin, including the Las Vegas metropolitan area. The river also supplies irrigation water for about 5 million acres of agricultural land, including California farms providing a significant portion of the nation’s fruit and vegetables.

Climatologists and other water supply experts say a long-term drought is being exacerbated by climate change, which is altering how much water falls on the Rocky Mountains as snow before melting into the Colorado River. The river serves seven Western states, Native American tribes and two northern Mexican states with water for agriculture, irrigation and drinking, hydroelectricity, recreation, and fish and wildlife habitat.

Water enters the 1,400-mile-long Colorado River as rain, snowmelt and runoff from the Rocky Mountains and flows through the Grand Canyon, down to Lake Powell, the nation’s second-largest reservoir, which is held back by the Glen Canyon Dam. The water flow powers Glen Canyon Dam’s hydroelectric turbines, then flows downstream to end up in Lake Mead, where it is distributed to lower basin states after again generating electricity.

Because the river and its reservoirs are insufficient to meet water demand, famers and cities have been pumping groundwater from aquifers, which have been losing water at an increasing rate, according to NASA. Since 2002, the reservoirs and the aquifers have lost a combined 13.7 trillion gallons of water, according to recent NASA estimates.

Worsening crisis follows years of tug-of-war over water rights

The record-low level recorded at Lake Mead comes days after federal authorities released a plan to deal with water shortages, which includes cuts to the amount of water that can be drawn by states in the Colorado River’s lower basin, including Arizona, California and Nevada.

Officials in the seven Western states have been battling over the river for more than a century, particularly as the West’s increasing population has demanded more water at a time of persistent drought.

The federal government issued a 10-year management plan and environmental impact statement to address water shortages in the Colorado River and plans to release additional details in the coming days. That plan calls for significant water-use cuts by California, Arizona and Nevada and voluntary reductions by Colorado, Wyoming, New Mexico and Utah.

Arizona officials were alarmed at the cuts federal officials are calling for in the three states in the river’s lower basin, the Arizona Republic has reported. The state’s water resources director, Tom Buschatzke, has said his team continues to negotiate with the other six states and federal decision-makers.

Because of extended drought, the combined water volume of Lake Mead and Lake Powell hasn’t been this low since before Lake Powell began to fill in 1963, according to the Department of Interior. The department’s letter introducing the environmental impact document states that the “risk to the system has never been greater.”

Lake Powell is now at 3,521.43 feet and has fallen almost 4 feet in the past 30 days. Federal officials say it probably will hit its lowest level ever by early spring, if not sooner.

Udall said the new federal plan is a solid start to addressing the issues he and others have been warning about for decades. But he worries too many people across the West believe the forecast super El Niño will bring significant relief to the area.The long-term trends, he said, remain dire, even if this winter is a wet one. He said Lake Mead’s future is “frightening” unless states, Native American tribes and the Mexican government can agree to use significantly less water.

“Mostly, I’m sad that we haven’t done more with all the knowledge we had,” Udall said. “We’re asking people to do really hard things. But failure to do them has completely unacceptable consequences. We are living on the edge.”

Las Vegas cuts water usage as supply dwindles

Water users in the Las Vegas area have cut demand dramatically over the past 20 years, reducing per capita use by 58% even as the population grew by 876,000 people, according to the water authority.

In 2022, the Southern Nevada Water Authority completed work on a project to ensure it could still pump drinking water from Lake Mead to serve the Las Vegas area when water levels are low. Launched in 2008, the effort includes both a new low-level water intake closer to the lake’s bottom and a pumping station to lift that water back up 500 feet.

The water district has been paying residents to rip out their thirsty grass and replace it with landscaping or trees, banned most new commercial fountains and water features, and limited the amount of water golf courses may use.

More than 250 million square feet of grass – the equivalent of 9 square miles – has been removed, and authorities have helped residents buy an estimated 45,000 removable swimming pool covers, saving at least 5.6 billion gallons from evaporating in the desert heat.