US officials first issued an official water shortage declaration for the huge western Lake Mead Reservoir on Monday, leading to power outages in drought-stricken parts of the Southwest.
The shortage will reduce water distributions to Arizona, Nevada and Mexico for the year beginning in October, the US Office of Recovery said in a statement.
Arizona will lose 18% of its annual distribution, while Nevada will see cuts of 7%. The allocations to Mexico, which are required under a 1944 treaty, will be reduced by 5%.
While not a surprise, the cuts will mean less water, and difficult allocation decisions, for farms, cities and tribes in the parched region, which is in its 22nd year of drought.
“We are seeing the effects of climate change,” said Tanya Trujillo, undersecretary of water and science for the Department of the Interior, during an online press conference.
He noted lower-than-average snow cover for the region, scorching temperatures and dry ground conditions.
“Unfortunately, that trend can continue,” Trujillo said.
Lake Mead, formed in the 1930s from the Colorado River Dam on the Nevada-Arizona border, is the largest reservoir in the United States. It is crucial for the water
supplying 25 million people in the cities of Los Angeles, San Diego, Phoenix, Tucson and Las Vegas.
The devastating drought in the western US has pushed Lake Mead and Lake Powell, the second-largest reservoir in the country, to record lows. Total water storage in the Colorado River system is at 40% capacity, up from 49% a year ago, the office said.
The water emissions in a given year are determined by an annual study that anticipates the water levels of the reservoirs in winter.
In January, Lake Mead is expected to be 1,065.85 feet (324.9 meters) above sea level, 9 feet below the official stock-out level.
The reservoir’s elevation is projected to continue dropping, the agency said. As of July 2023, it is estimated at 1,037.73 feet. Arizona, California and Nevada are considering actions necessary to prevent the reservoir from descending below 1,020 feet, authorities said.
Last month, an emergency drought settlement triggered the release of 181,000 acre feet of water from smaller western storage reservoirs to increase the elevation of Lake Powell.