Years of overconsumption colliding with the stark realities of climate change are pushing Colorado River reservoirs so dangerously low that major dams on the river could soon become critical supplies of water to millions in the Southwest, state and federal authorities say. obstacle.
The federal government has called on seven western states that depend on the Colorado River to reduce their water use by 2 to 4 million acre-feet — as much as a third of the river’s average annual flow — to try to avoid such dire consequences. But the states have so far failed to reach a voluntary agreement on how to achieve that, and the Home Office could impose unilateral cuts in the coming months.
“Without immediate and decisive action, the elevated elevations of Lake Powell and Lake Mead could force the system to cease functioning,” Interior Undersecretary Tommy Bodlow told a meeting of Colorado River officials here on Friday. “This is an intolerable situation and we will not allow it to happen.”
Many state water officials fear they are running out of time.
Ted Cook, general manager of the Central Arizona Project, which brings water from the Colorado River into central Arizona, said there is “a real potential for an effective dead pool to form” within the next two years. That means water levels could drop to Glen Canyon and the Hoover Dam — building reservoirs at Lake Powell and Lake Mead — would become a barrier to water supplies to cities and farms in Arizona, California and Mexico.
“At certain times of the year, we may not be able to get water through either of the two dams in the main reservoir,” Cook said. “It’s on our doorstep.”
The looming crisis energized the annual gathering of water bureaucrats, with cowboy hats occasionally seen among the standing crowd at Caesars Palace. Organizers said it was the first time the conference was sold out, and the specter of mass shortages loomed as state water managers, tribes and the federal government met to discuss how to cut water use on an unprecedented scale.
“I can feel the anxiety and uncertainty in this room and in the basin,” said Reclamation Director Camille Calimlim Touton.
Negotiations will ultimately have to weigh cuts to rapidly growing urban areas against the farming communities that produce most of the country’s winter vegetable supply. In the complex world of water rights, farms often have priority over cities because they use river water longer. Unlike past negotiations, water managers now expect the cuts to affect even the most senior water users.
States in the upper Colorado River Basin — Colorado, New Mexico, Utah and Wyoming — say it’s difficult to specify how much they can cut because they rely less on reservoir allocations and more on the variable flow of rivers. flow. The states in the lower basin—California, Arizona, and Nevada—use much more water, too.
“In the upper basin, we can say we’re going to take 80 percent and nature is giving us 30 percent,” said Gene Shawcroft, president of the Colorado River Authority in Utah. challenge.”
The federal government set an August deadline for states to reach a voluntary agreement on cuts, but that deadline passed without a deal. Some state officials here are blaming the Biden administration. When it became clear this summer that the federal government was not prepared to implement unilateral cuts, the urgency for a deal evaporated, they said.
Now, the Biden administration has launched a new environmental review to distribute Colorado River supplies during low-water conditions. Water managers hope to have more clarity on what states can offer by the end of January. By summer, the federal government is expected to finalize its powers to impose unilateral cuts.
“Unfortunately, it’s a year later than we needed to be,” Cook said in an interview.
Across the West, the drought has led to a record number of wells in California, forcing swaths of farmland to fall fallow and asking homeowners to limit how much they water their lawns. This week, a major water provider in Southern California declared a regional drought emergency and called on those that depend on water from the Colorado River to reduce imported supplies.
Problems on the river have persisted for years. Over the past two decades, during the region’s worst drought in centuries, the Colorado River Basin states have drawn more water from their rivers than they produced, drying up reservoirs that act as buffers during troubled times. James Prairie, head of the Bureau of Reclamation’s research and modeling team, said the river’s annual flow during the period averaged 13.4 million acre-feet, while users pumped an average of 15 million acre-feet per year.
In 1999, the country’s two largest reservoirs, Lake Mead and Lake Powell, held 47.6 million acre-feet. That’s down to about 13.1 million acre-feet, or 26% of their capacity. An acre-foot equals 326,000 gallons, or enough to cover an acre of land with one foot of water.
Federal officials predict that as soon as July, the water level at Lake Powell could drop to the point where the hydroelectric plant inside the Glen Canyon Dam can no longer produce electricity, and then keep dropping so much that it can no longer deliver much of the water that the Southwestern states depend on. . Water managers say the same “dead pool” could appear in Lake Mead within two years.
“These reservoirs have served us for 23 years, but we’re pushing them to the limit now,” Prairie said.
Bureau of Reclamation Deputy Administrator David Palumbo highlighted the effects of climate change — hotter and drier out west where the ground absorbs more runoff from mountain snow before reaching reservoirs — Meaning the past is no longer useful to guide the river’s future. Even in a snowy year, runoff is now low, he said.
“Runoff efficiency is critical and requires awareness and, frankly, fear,” he said.
Water managers say most of the cuts are likely to occur in southern states, including Arizona and California, where major agricultural regions consume most of the available supply. Those states, which take water after it flows through Lake Mead and the Hoover Dam, are also at greatest risk if reservoir levels drop to dangerous levels, said John Entsminger, general manager of the Southern Nevada Water Authority. .
“If you can’t get water through the Hoover Dam, that’s water for 25 million Americans,” he said.