Aug. 17 (UPI) — The federal government on Monday declared a water shortage in the Colorado River Basin for the first time, prompting mandatory water consumption cuts throughout the Southwest.
In its August 2021 24-Month study, the Bureau of Reclamation said that Lake Mead, the largest reservoir in the United States by volume, was 1,067 feet above sea level and at 35% capacity.
The agency predicted the lake is expected to remain near 1,066 feet into 2022, leading it to announce the Colorado River will enter the first tier of water cuts beginning Jan. 1.
“Like much of the West, and across our connected basins, the Colorado River is facing unprecedented and accelerating challenges,” Interior Department Assistant Secretary for Water and Science Tanya Trujillo said in a statement. “The only way to address these challenges and climate change is to utilize the best available science and to work cooperatively across the landscapes and communities that rely on the Colorado River.”
Under the cuts, Arizona will see an 18% reduction of its total Colorado River Supply and Nevada will lose about 7%. The government will also reduce Mexico’s annual allotment of water from the river by 5%.
A second tier of cuts would be triggered if Lake Mead falls below 1,050 feet and could arrive as soon as 2023.
“Today’s announcement of a Level 1 Shortage Condition at Lake Mead underscores the value of the collaborative agreements we have in place with the seven basin states, Tribes, water users and Mexico in management of water in the Colorado River Basin,” Reclamation Deputy Commissioner Camille Touton said. “While these agreements and actions have reduced the risk, we have not eliminated the potential for continued decline of these critically important reservoirs.”
The cut is expected to have an impact on agriculture, particularly in Arizona.
Some farmers have fallowed their fields or switched to less water-intensive crops while others have begun pumping additional groundwater to compensate.
“The river is the iconic resource,” Kevin Moran of the Environmental Defense Fund told The New York Times. “But we have to think about managing our groundwater as well.”
A 2020 study by U.S. Geological Survey scientists found that the Colorado River’s flow has declined by about 20% throughout the past century with more than half of the decline attributed to warming temperatures.
Researchers added that the average discharge could decline by 31% compared to the historical average by the middle of the century unless significant reduction to planet-heating emissions occurs.
Brad Udall, senior water and climate scientist at Colorado Stae University, told CNN the decline in Lake Mead is “very significant.”
“It’s something that those of us in the climate community have been worried about for over a decade, based on declining flows due to climate change,” he said.