Lake Mead drops to lowest level since filling, deepening Colorado River crisis

Lake Mead, the largest reservoir in the United States, has fallen to its lowest water level since it was first filled roughly nine decades ago, marking a new milestone in the Colorado River's ongoing crisis.

Federal data shows the reservoir, which straddles the Arizona-Nevada border near Las Vegas, dipped to 1,040.4 feet above sea level on Friday. That reading edges past the previous record low of 1,040.58 feet, set in late July 2022.

The new low follows a winter that produced the worst snowpack on record in the Colorado River Basin. Melting snow feeds the river, which supplies water to more than 40 million people across seven U.S. states, tribal nations, and Mexico, as well as to farms, industries, wildlife, and hydropower producers.

The development comes just a week after federal officials put forward a short-term plan to prevent a full-blown collapse of the waterway. The move followed the failure of the seven basin states — California, Colorado, Arizona, Nevada, New Mexico, Wyoming, and Utah — to agree on long-term sharing of the dwindling supply. Under the federal proposal, California, Nevada, and Arizona would take the largest cuts.

Years of overuse, combined with drought and rising temperatures, have steadily drained both Lake Mead and Lake Powell, the nation's second-largest reservoir. Together, the two bodies of water are at their lowest combined level in nearly seven decades.

To protect the strained system's hydropower capacity, federal officials said Thursday they will not release cool water from Glen Canyon Dam in northern Arizona. The decision is intended to shield a threatened native fish species whose habitat lies between the two reservoirs.

The severity of the drought was already visible last year, when receding waters at Lake Mead exposed human remains and forced Las Vegas water authorities to draw from deeper parts of the reservoir to keep supplying millions of residents.