(CNN) — The combined water level in two of the United States’ biggest reservoirs, Lake Powell and Lake Mead, has fallen to a historic low, in what experts are calling a significant moment in the Colorado River crisis — threatening a water system that supplies tens of millions.
On July 12, Lake Powell was at 3,524 feet and Lake Mead was just under 1,043 feet, breaking a record set in March 2023, according to an analysis published by five Colorado River experts last week. Together, the two reservoirs haven’t been this low since 1957, during the construction of the Glen Canyon Dam, before Lake Powell even existed.
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It’s “a milestone in the history of water storage in the Colorado River Basin,” said Jack Schmidt, director of the Center for Colorado River Studies at Utah State University and an author on the analysis. The record reveals “the seriousness of the uniquely small amount of water that is presently stored in the basin’s reservoirs,” he added.
The Colorado River is the lifeblood of the Southwest. It irrigates more than 5 million acres of farmland, generates enough electricity to power around 700,000 homes and provides water for 40 million people.
The headwaters of this 1,400-mile long artery are in the Rocky Mountains, fed by melting snowpack. The river flows across seven states, filling Lake Powell and Lake Mead as it winds toward the Gulf of California. The two lakes, which are essentially one gigantic reservoir separated by the Grand Canyon, hold just under 60% of the total water currently stored in the basin.
The Colorado River has shrunk rapidly over the past 25 years as water demand has boomed and climate change has delivered hotter, drier weather and dwindling snow. Today, 95% of the basin is in drought.
Last winter was not kind. The western US had one of the driest, warmest winters on record, leaving the region in a snow drought. Snowpack acts as a natural water tower, and without enough the reservoirs are suffering.
Levels in both lakes have fallen further since the record was first set last week. Lake Powell, currently 23% full, is at its lowest level on record for July, and, based on current rates of decline, could reach its all-time record low sometime next month. Lake Mead is 27% full and less than a foot from its all-time record low, set in July 2022.
The researchers predict Lake Mead and Lake Powell will set a new record low for their combined water storage every day from now until next spring, when the runoff from the winter snowpack starts to replenish water levels.
Lake Powell could fall so low by spring 2027 that it reaches “minimum power pool” level, meaning its dam will no longer be able to generate hydropower, according to a July report from the Bureau of Reclamation.
This report “highlights the ongoing vulnerability of the Colorado River system and reinforces the urgent need for updated guidelines and procedures,” said a Reclamation spokesperson.
Things could get even worse, experts say. “The low reservoir levels are a dramatic signal that the system is at risk of crashing, meaning reservoir levels so low that water cannot be delivered from them,” said Sarah Porter, director of the Kyl Center for Water Policy at Arizona State University.
It may influence the fraught negotiations between the seven states on how to share the Colorado River’s diminishing water.
Under the 1922 Colorado River compact, the four states in the Upper Colorado River Basin (Colorado, New Mexico, Utah and Wyoming) are allotted 7.5 million acre-feet of water every year and another 7.5 million goes to the three in the Lower basin (California, Arizona and Nevada).
The shrinking river means states are going to have to accept less, but how this works in practice has yet to be ironed out. A federally-imposed February deadline for states to agree came and went with no deal.
The negotiations are complex, Porter said. States are being asked “to agree to deep cuts and potentially new and complex management strategies that they have to go back to their states and ‘sell’ to their water users and decision makers.” But, she added, “the new low may be a catalyst.”
On Tuesday, Interior Secretary Doug Burgum held a virtual meeting with governors of the seven basin states to address the state of the Colorado River. In a statement afterward, he praised the governors “for their leadership and commitment to finding solutions to address drought conditions” and said, “Interior remains focused on establishing a new operating framework.”
The Bureau of Reclamation will release new operating guidelines in the coming weeks, “providing a robust framework for managing future river operations and addressing the challenges ahead,” the spokesperson said.
There is hope for some relief. Drought could start to improve in the fall and winter thanks to El Niño, which tends to bring more frequent rain and snow to the Southwest.
But experts say that’s unlikely to lead to much long-term improvement. “Even record snowpack this winter will not be enough to get us out of the danger zone,” ASU’s Porter said.
Immediate action is needed, Schmidt said, including big investments in making farmers’ water use more efficient and ensuring the right crops are grown in the right areas.
“I worry that there remains too much hope that we will be saved by the coming winter snowpack,” Schmidt said. “Hope and prayer is no way to run a national water system.”
CNN’s Ella Nilsen and Lead Meteorologist Brandon Miller contributed to this report
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