New water restrictions will hit the states of the Colorado Basin, the great river of the American West, plagued by unprecedented aridity. On Tuesday, August 16, Camille Touton, the director of the Bureau of Reclamation, the federal agency that manages water and dams, said that the drought which is raging for the twenty-third year in the region is reaching “a point of no return”.
The two largest reservoirs in the country, Lake Powell and Lake Mead, are within “historically low levels”, she added, which require exceptional measures to guarantee the production of hydroelectricity. The office declared a “category 2 shortage”which will force Arizona and Nevada to reduce their consumption from January 2023. Mexico is also affected.
The Colorado, 2,320 km long, supplies water and hydroelectricity to 40 million people in seven states, and 29 Indian tribes. The distribution of the annual flow of the river was defined by the Colorado Compact of 1922, signed with Mexico. This treaty provides for a solidarity mechanism between the states of the upper basin – the first on the route of the river (Colorado, Utah, Wyoming, New Mexico) – and those of the lower basin (Arizona, Nevada, California). The northern states must allow enough water to pass through so that the south does not lack it.
In 2019, the drought forced the negotiation of an additional emergency plan to save reservoirs threatened with falling below the level required for hydroelectric production. According to the agreement, a mechanism of restrictions is put in place as soon as the level drops below 325 m (1,066 feet) above sea level at Lake Mead, 50 km from Las Vegas. It should have been activated in 2021, for the first time since the inauguration of the Hoover Dam in 1935. Arizona had lost 18% of its water allocation, Nevada, 3%. This summer, Lake Mead is only filled to 27% of its capacity. In January 2023, the bureau predicts the level will fall below 316 m (1,040 ft).
California not affected at this time
Upstream, Lake Powell, on the border between Utah and Arizona, is also at its lowest since the inauguration of the Glen Canyon dam in 1964, and at 26% of its capacity. The authorities have taken exceptional measures to continue to power the turbines that generate electricity for 1.5 million homes. They withheld 592 million cubic meters that should have fed Colorado, further reducing the inflow to Lake Mead.
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