BOULDER CITY, Nev. — The federal government declared an unprecedented water shortage for the Colorado River and Lake Mead on Monday, triggering mandatory water cuts and opening a new chapter in the worsening struggle with drought in the West.
Water supplies from the Colorado River for Arizona, Nevada and parts of Mexico will be reduced starting in January after the U.S. Bureau of Reclamation, an agency of the Interior Department, issued a formal shortage declaration for the river for the first time.
Although the first round of cutbacks will affect mainly farmers, sparing cities and homes in the short term, further drops in Lake Mead's water levels would trigger much deeper water reductions that could ultimately affect cities like Phoenix, Las Vegas and Tucson, Arizona, as well as parts of California.
"Like much of the West and across our connected basins, the Colorado River is facing unprecedented and accelerating challenges," Assistant Interior Secretary Tanya Trujillo said.
Scientists say a combination of natural weather patterns and human-driven climate change is fueling the historic drought and dwindling water levels in Lake Mead and throughout the Colorado River system.
Temperatures at Lake Mead hit 106 degrees Monday as a few boaters and swimmers cooled off in the lake, the country's largest reservoir. Towering above them was a tall shoreline streaked with wide, white stripes — rings left behind from just a couple of decades ago, when the water levels were more than 100 feet higher.
John Entsminger, who manages the Southern Nevada Water Authority, said his region will be able to easily absorb the initial cuts because of steps that were undertaken to reduce water demand, including cracking down on water-intensive landscaping. He described the situation as "extremely serious but not apocalyptic."
"We have a plan for that worst-case scenario right now. We've planned for the very bad," Entsminger said. "We have not planned for the absolute worst."
The water shortage declaration had been widely anticipated since May, when Lake Mead fell below 1,075 feet, the trigger point for "Level 1" water cuts in an agreement among states that rely on water from the Colorado River. The Bureau of Reclamation predicted Monday that in January, when the cuts take effect, water level will be at 1,066 feet.
Lake Mead, which sits just above Hoover Dam, feeds the lower Colorado River basin, part of a longer Colorado River system that provides water for 40 million people and electricity for millions through hydroelectric dams that control the river's flow.
Under the Level 1 cuts, Arizona will face the biggest reduction: 512,000 acre-feet, or about one-fifth of the state's allotment from the Colorado River and about 8 percent of Arizona's overall water supply. Farmers who rely on water from the Central Arizona Project canal will be most directly affected, local officials said.
At a farmer's market on the outskirts of Las Vegas, farmer Lea Bales ducked under a tent for shade from the powerful heat as she hawked squash, melons and carrots from her farm in Pahrump, Nevada — the last of the season's harvest before the fall crops go in. She said she worried that future water cuts would make her way of life unsustainable.
"I probably would not have a farm," Bales said. "Either that or I would just go so small-scale, just, like, for personal use. Because it takes a lot of water to grow a lot of vegetables."