SUMAN NAISHADHAM, Associated Press
U.S. officials on Monday declared the first water shortage in a river that supplies 40 million people in the west and sparked cuts for some Arizona farmers the next year amid a gripping drought.
The water level of the largest reservoir on the Colorado River – Lake Mead – has fallen to record lows. Along its perimeter, a white “bathtub ring” made of minerals marks the spot where the flood line once stood and highlights the acute water problems for a region facing a growing population and drought caused by hotter and drier weather due to climate change is aggravated.
States, cities, farmers and others have diversified their water sources over the years to mitigate the impending cuts. Federal officials said Monday’s statement made it clear that conditions worsened faster than scientists predicted in 2019 when Arizona, Nevada, California and Mexico agreed to ditch portions of their water to keep Lake Mead levels down.
“Today’s announcement is a recognition that the hydrology that was planned years ago – but we hoped we’d never see it – is here,” said Camille Touton, Commissioner for the Bureau of Reclamation.
Lake Mead was created when the Hoover Dam was built in the 1930s. It is one of several man-made reservoirs that store water from the Colorado River, which provides household water, farm irrigation, and hydropower to Arizona, California, Colorado, Nevada, New Mexico, Utah, Wyoming, and parts of Mexico.
But water levels in Lake Mead and Lake Powell, the river’s two largest reservoirs, have been falling for years and faster than experts predicted. Searing temperatures and less melting snow in the spring have reduced the amount of water that flows from the Rocky Mountains, where the river originated, before winding 1,450 miles southwest into the Gulf of California.
“We are in a moment where we are thinking about how we can continue to thrive with less water, and it is very painful,” said Sarah Porter, director of the Kyl Center for Water Policy at Arizona State University.
HOW IS RIVER WATER DIVIDED?
The water stored in Lake Mead and Lake Powell is shared by legal agreements between the seven states of the Colorado River Basin, the federal government, Mexico, and others. The agreements stipulate how much water everyone gets, when cuts are triggered and in what order the parties must sacrifice part of their supply.
As part of a 2019 drought contingency plan, Arizona, Nevada, California and Mexico agreed to abandon portions of their water to maintain Lake Mead water levels. The voluntary measures were not enough to prevent the defect from being declared.
WHO SERVES SEE MEAD?
Lake Mead supplies water to millions of people in Arizona, California, Nevada, and Mexico.
Cutbacks for 2022 are triggered when the predicted water level drops below a certain threshold – 1,075 feet above sea level, or 40% capacity. Hydrologists predict the reservoir will drop to 1,066 feet by January.
Additional rounds of cutting are triggered when the projected levels drop to 1,050, 1,045, and 1,025 feet.
Finally, some urban and industrial water users could be affected.
The level of Lake Powell is also falling, threatening the approximately 5 billion kilowatt hours of electricity generated at Glen Canyon Dam each year.
Colorado, New Mexico, Utah, and Wyoming receive water from tributaries and other reservoirs that flow into Lake Powell. Water from three reservoirs in these states was drained to maintain Lake Powell water levels and protect the electricity grid operated by Glen Canyon Dam.
WHICH STATES ARE AFFECTED BY THE SHORTS?
In the US, Arizona will be hardest hit, losing 18% of its share to the river, or 512,000 acre-feet of water, next year. That is around 8% of the state’s total water consumption.
One acre foot is enough to supply one to two households a year.
Nevada will lose about 7% of its allotment, or 21,000 acre-feet of water. But it won’t feel the shortage due to conservation efforts and alternative water sources.
California will be spared immediate cuts because it has more water rights than Arizona and Nevada.
Mexico will see a reduction of about 5%, or 80,000 acre-feet.
WHO IN THESE STATES WILL CUT YOUR WATER SUPPLIES?
Central Arizona farmers, who are among the largest producers of livestock, dairy products, alfalfa, wheat and barley, will bear the brunt of the cuts.
Your allocation comes from water that is classified as “extra” by the authority that supplies a large part of the region with water.
As a result, farmers will likely – like many in recent years due to prolonged drought – fallow land and be even more dependent on groundwater, switch to water-efficient crops and find other ways to use less water.
Water suppliers have planned to explain the deficiency by diversifying and conserving their water supply, for example by storing water in underground basins. Nevertheless, water cuts make planning for the future difficult.
The Central Arizona Project, which supplies water to major Arizona cities, will stop creating river water or replenishing some groundwater systems next year because of the cuts.
“It’s a historic moment when drought and climate change are at our door,” said Chuck Cullom of the Central Arizona Project.
Cities like Las Vegas, Phoenix and Tucson as well as Indian tribes will be shielded from the first round of cuts.
CAN THE LAKE MEAD DECREASE BE RESET?
The water level of the reservoir has fallen since 1999 due to the dry period in the west and the increased water demand. Given the expected deterioration in weather, experts say the reservoir may never be full again.
Although Lake Mead and Lake Powell could theoretically be replenished, planning for a hotter, drier future with less river water would be more prudent, said Porter of Arizona State University.