‘Megadrought’ forces first-ever Colorado River water rationing

Denver: Federal officials have ordered the first-ever water cuts on the Colorado River system that sustains 40 million people, the latest blow from a decades-long drought across the American west that has shrunk reservoirs to historic lows, devastated farms and set the stage for deadly forest fires.

The move will deal a harsh setback to Arizona farmers, who will suffer the largest cuts. Water deliveries to Nevada and Mexico will drop as well under a system hammered out in 2019 by the communities that rely on the river. And with the possibility of another dry La Nina winter looming, more reductions could follow.

“What we hoped we’d never see is here,” said Camille Touton, deputy commissioner of the US Bureau of Reclamation, during a news conference on Monday. “And the hydrology might not be the worst we are likely to see.”

This July 27 satellite image provided shows the low water level at the Boulder Harbor Launch Ramp at Lake Mead in Boulder City, Nevada.Credit:Maxar/AP

The Colorado, running 2330 kilometres from the Rocky Mountains to the Gulf of California, is a primary water source from Denver to Los Angeles, while also irrigating crops and supplying hydropower plants. So much water is taken out of the Colorado, in fact, that it rarely reaches its historical delta, even in relatively wet years.

And such years have grown scarce as a “megadrought”, a dry period of unusual length and severity, grips the west. According to the Bureau of Reclamation, the amount of water flowing unregulated into the river’s Lake Powell from 2000 to 2020 was lower than in any other 21-year period since the reservoir’s inception. Environmentalists say the river can’t afford any significant new diversions, even as the region’s population continues to grow.

“The Colorado River is drying out, and western states need to act now to protect this vital waterway and its tributaries,” Bart Miller, director at the Healthy Rivers Program for the Western Resource Advocates environmental group, said in a statement.

A buoy once used to warn of a submerged rock rests on the ground along the waterline near a closed boat ramp on Lake Mead at the Lake Mead National Recreation Area.Credit:AP

The water level at Lake Powell now stands at 3551 feet (1082 metres) above sea level, or just 32 per cent of capacity. At Lake Mead, it’s at 1068 feet above sea level, or 35 per cent of capacity.

Both reservoirs are close to a point once considered unthinkable – where the flow is so small that hydropower dams are forced to shut. At Lake Mead, it’s at 1068 feet above sea level, or 35 per cent of capacity. Lake Powell’s Glen Canyon Dam, for example, can’t generate electricity if the water level drops below 3491 feet.

Rights to use the Colorado’s water are governed by nearly a century of agreements among states, the federal government and Mexico, a legal document collectively known as the Law of the River. The Bureau of Reclamation on Monday declared a Tier 1 shortage.

Arizona’s annual allotment will be cut by 18 per cent starting next year. Nevada and the nation of Mexico will incur reductions of 7 per cent and 5 per cent, respectively. (The other states that draw water from the river are California, Colorado, New Mexico, Utah and Wyoming.)

Paul “Paco” Ollerton and his dog look towards the canal system that delivers Colorado River water to his farm near Casa Grande, Arizona.Credit:AP

Arizona’s reduction will be equivalent to the amount used by about 1 million average households in a year. The cuts will not affect any municipal, industrial, commercial or tribal users. Instead, almost all the cutbacks will fall on farms that receive their water from the Central Arizona Project.

The rationing will likely hit hardest in Pinal County, where farmers tend to have the most junior water rights. Farms there will have to let lands go fallow or rely on groundwater that’s already over pumped. While Arizona is trying to cushion the blow by building out groundwater infrastructure, some observers say the cuts will provoke litigation.

“Pinal County agriculture faces a dire reality,” the Arizona Farm Bureau said in a statement. “This will have a devastating impact on each farming family in that county, and the surrounding communities will feel the ripple effects for years to come.”

Tom Buschatzke, director of the Arizona Department of Water Resources, said some of the water the state will be losing has been stored underground and can now be used to mitigate the shortfall. Many Central Arizona Project farms in Pinal, Pima and Maricopa counties “will be losing substantial amounts of their surface water, and we’ll be able to offset their losses by pumping groundwater under our Groundwater Management Act,” he said, during Monday’s press conference.

John Entsminger, general manager of the Southern Nevada Water Authority, said his agency has “pre-conserved” the cuts it will be seeing in 2022, meaning there will be no reductions in water to its member agencies.

Should the drought continue next year, California could face supply reductions: the Golden State must forgo water when Lake Mead falls below 1045 feet.

That’s a strong possibility. The US Climate Prediction Centre last week forecast a 62 per cent chance that the La Nina phenomenon in the Pacific Ocean would return this northern autumn, its second appearance in two years. La Nina typically brings dry winters to the south-west. While the summer monsoon season this year has brought frequent thunderstorms, they have not made a dent in the drought. And with climate change, many long-term models predict a more arid future for the region.

“The possibility of back-to-back La Nina years is always there, and we’ve had them before,” said Park Williams, a climate scientist at the University of California, Los Angeles. “Having that after a 21-year period where it’s been mostly dry is starting to put us up against the ropes.”


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