The U.S. is dry and getting drier. Federal officials said this week that a major source of water for the U.S. Southwest could face some of its first official water restrictions later this year if water levels keep dropping.
New projections issued by the Bureau of Reclamation predict that the water levels in Lake Powell and Lake Mead, two manmade reservoirs along the Colorado River, will reach historically low levels in the coming months. The water level at Lake Mead is sitting at just 39%, while Lake Powell is at 36%. The government predicts that Lake Mead’s water level will fall below 1,075 feet (328 meters) by June, the level which triggers official government water shortage procedures for the seven states that get their water from the Colorado River.
The Colorado River is the West’s most important water source, suppling Arizona, California, Colorado, Nevada, New Mexico, Utah, and Wyoming with freshwater for drinking and agriculture. It also serves communities in Mexico as well. More than 40 million people and millions of acres of farmland rely on the river.
“For decades now [the river] hasn’t been running as much as they’d like for the water use, and there’s a number of reasons for that,” Richard Seager, a climate scientist at Lamont-Doherty Earth Observatory at Columbia University, said. Natural variability in weather patterns, including a La Niña event last winter and a dry summer season in 2020 that saw reduced precipitation across the region, was partially responsible for the low levels, Seager said. The river, Seager explained, has also historically suffered from overallocation that has only become more and more exacerbated. “Everything in the river is already allocated for use, and as the population goes up, there’s more pressure,” Seager said.
Then, of course, there’s climate change. The region the river runs through is in the midst of a historic megadrought, likely brought on partly by climate change. Rising temperatures have cut into snowpack that serves as crucial sources of water for the river and exacerbated drought conditions by increasing water evaporation. A study published last year found that for each 1.8 degrees Fahrenheit (1 degree Celsius) of warming in the basin’s region, the river’s flow could decrease by as much as 10% and could be down by as much as 30% by midcentury.
Water distribution from the river relies on a set of interim guidelines created in 2007, which were intended to dictate how the water supply should be managed for a new, warming world. But soon after the guidelines were drafted, the West was plunged into a decade of serious drought. Regulators knew they had to act, and in 2019, the states reached a contingency agreement that would cut back on water deliveries to certain regions, dictated by Lake Mead reaching certain levels. The first tier of cuts was triggered in the summer of 2019 after Lake Mead reached 1,090 feet (332 meters), with Arizona and Nevada implementing their first cutbacks. (Those cuts were relatively minor, as both states had already been working to scale back their water use voluntarily.)
Officials say that preparation measures being undertaken in states would probably mean that consumers won’t directly feel the impacts of the next round of cuts, should the lake cross the 327.66 m threshold. But farms in central Arizona, which are first in line to cut their water share under the drought contingency plan, could see serious reductions as an important water delivery system in the state would see its water supply cut by one-third by next year.
“We’ll have to lay off employees,” Dan Thelander, a farmer in the region, told CNN of the possible cuts, saying that he may have to leave up to 40% of his land fallow. “We won’t be buying as many seeds or fertiliser or tractors, and so we’ll just have to scale down and operate a smaller farm. And so, yes, it’ll hurt a lot.”
And it’s not just agriculture that could be affected by low water levels. The water in Lake Mead also serves to power the Hoover Dam, which generates enough hydropower to serve 1.3 million people each year in Nevada, Arizona, and California. Less water in the lake, however, could mean less electricity generated by the turbines in the dam. While a dam manager told the AP that the government has been making changes to the turbines to prepare for them to function with less water, the lowering levels in the lake will probably mean that there will be less hydropower from the dam in the future.
There’s always a chance that a wetter spring or other favourable weather could reverse course and pump water levels back up to prevent restrictions from happening this time, but the odds aren’t looking good for that. The National Oceanic and Atmospheric Administration forecast for the next three months — already the start of the dry season for the West — are likely to be even drier than normal. Drought, meanwhile, is forecast to linger in the river basin and could even worsen. This latest drama on the river is, undoubtedly, a signal for its long-term future.
“All the climate change projections say there will be less water in the river,” said Seager. “Dealing with these things now is always sort of good planning for what’s going to come. The region is going to have to adapt to having less water available.”