Drastic water cuts imposed as ‘megadrought’ grips western US states

theguardian.com:

Severe water cuts were announced on Tuesday to western states in the grip of a severe “megadrought” that has dropped levels in the country’s largest two reservoirs to record lows.

The US Department of the Interior has declared the first-ever tier 2 shortage for the Colorado River, meaning Arizona, Nevada and Mexico must further reduce their water usage from 1 January next year.

Arizona will face the largest cut: 592,000 acre feet, or 21% of the state’s current river draw, officials said. Restrictions to other states, including California, may follow.

The crisis, which has dropped levels in Lake Mead, the largest reservoir in the US, to an 80-year low of barely one-quarter its 28.9m acre-feet capacity, is threatening the survival of the crucial river basin.

It has also led to potential disruption of water delivery and hydropower production, forcing the federal government to take such drastic action.

The 24m acre-feet Lake Powell, meanwhile, is enduring a similar catastrophe, with the Guardian reporting in July that energy production could halt as soon as July 2023.

An interior department projection that Lake Mead’s 1 January level would be below 1,050ft above sea level triggered the declaration of the country’s first tier 2 shortage.

Lake Powell’s water surface elevation is projected to be at 3,522ft, only 32ft from the minimum needed to generate electricity from hydroelectric operations.

“Every sector in every state has a responsibility to ensure that water is used with maximum efficiency,” the interior department’s assistant secretary for water and science, Tanya Trujillo, said in a statement. “In order to avoid a catastrophic collapse of the Colorado river system and a future of uncertainty and conflict, water use in the basin