CNN
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Lake Powellthe second-largest man-made reservoir in the United States, has lost nearly 7% of its potential storage capacity since 1963, when the Glen Canyon Dam was built, according to a new report.
In addition to water loss due to intense multi-year droughtthe US Geological Survey and the Bureau of Reclamation report foundLake Powell faced an average annual loss of storage capacity of about 33,270 acre-feet, or 11 billion gallons, per year between 1963 and 2018.
That’s enough water to fill the National Mall’s Reflecting Pool about 1,600 times.
Reservoir capacity decreases due to sediment flowing from the Colorado and San Juan Rivers, according to the report. These sediments settle to the bottom of the tank and decrease the total amount of water the tank can hold.
As of Monday, Lake Powell was about 25% full, according to data from the Bureau of Reclamation.
This is bad news for a region already facing water shortages and extreme drought-induced wildfires. Drought experts from the National Oceanic and Atmospheric Administration said last week that these conditions were should at least continue – if not worsen – in the coming months.
Lake Powell is a major reservoir in the Colorado River Basin. Lake Powell and nearby Lake Mead, the nation’s largest reservoir, have been draining at an alarming rate. In August, the federal government declared a water shortage on the Colorado River for the first time after Lake Mead’s water level plunged to unprecedented levelstriggering mandatory water use reductions for Southwestern states that began in January.
And last week Lake Powell dipped below the critical threshold of 3,525 feet above sea level, raising additional concerns about the water supply and hydroelectric generation on which millions of people in the West depend for electricity.
The significance of the dwindling water supply along the Colorado cannot be overstated.
The system provides water to more than 40 million people living in seven western states and Mexico. Lakes Powell and Mead provide an essential supply of drinking and irrigation water for many people in the region, including rural farms, ranches, and native communities.
“It is vitally important that we have the best scientific information available like this report to provide a clear understanding of water availability in Lake Powell as we plan for the future,” Tanya Trujillo, Assistant Secretary for Water and Science at the US Department of the Interior. , said in a statement. “The Colorado River system faces multiple challenges, including the effects of a 22-year drought and the increased impacts of climate change.”