US West Prepares for Possible 1st Water Shortage Declarationhttps://phys.org/news/2021-04-west-1st-shortage-declaration.htmlThe man-made lakes that store water supplying millions of people in the U.S. West and Mexico are projected to shrink to historic lows in the coming months, dropping to levels that could trigger the federal government's first-ever official shortage declaration and prompt cuts in Arizona and Nevada.
The U.S. Bureau of Reclamation released 24-month projections this week forecasting that less Colorado River water will cascade down from the Rocky Mountains through Lake Powell and Lake Mead and into the arid deserts of the U.S. Southwest and the Gulf of California. Water levels in the two lakes are expected to plummet low enough for the agency to declare an official shortage for the first time, threatening the supply of Colorado River water that growing cities and farms rely on.
It comes as climate change means less snowpack flows into the river and its tributaries, and hotter temperatures parch soil and cause more river water to evaporate as it streams through the drought-plagued American West.
The agency's models project Lake Mead will fall below 1,075 feet (328 meters) for the first time in June 2021. That's the level that prompts a shortage declaration under agreements negotiated by seven states that rely on Colorado River water: Arizona, California, Colorado, Nevada, New Mexico, Utah and Wyoming.
If projections don't improve by August, the Bureau of Reclamation will declare a Level 1 shortage condition. The cuts would be implemented in January.
Arizona, Nevada and Mexico have voluntarily given up water under a drought contingency plan for the river signed in 2019. A shortage declaration would subject the two U.S. states to their first mandatory reductions. Both rely on the Colorado River more than any other water source, and Arizona stands to lose roughly one-third of its supply.
The Bureau of Reclamation also projected that Lake Mead will drop to the point they worried in the past could threaten electricity generation at Hoover Dam. The hydropower serves millions of customers in Arizona, California and Nevada.
"As the elevation declines at the lake, then our ability to produce power declines as well because we have less water pushing on the turbines," he said.
"Rural economies in Arizona and Nevada live and die by the hydropower that is produced at Hoover Dam. It might not be a big deal to NV Energy," he said of Nevada's largest utility. "It might be a decimal point to Los Angeles Department of Water and Power. But for Lincoln County, it adds huge impact."
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https://mead.uslakes.info/level.asp... Based on current inflow forecasts, the current projected end of water year total Colorado Basin reservoir storage for water year 2021 is approximately 24.60 maf (41 percent of total system capacity).
