CNN
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Lake Powell, the second largest human reservoir in the United States, has lost almost 7% of its potential storage capacity since 1963 when Glen Canyon Dam was built.
In addition to severe multi-year droughts and water losses reported by the U.S. Geological Survey and the Bureau of Reclamation, Lake Powell faced an average annual loss of approximately 33,270 acre feet per year, or 11 billion gallons of storage capacity, between 1963 and 2018.
It's enough water to fill the National Mall reflective pool about 1,600 times.
The reservoir capacity has been reduced as it flows from the Colorado and San Juan rivers. These sediments settle at the bottom of the reservoir, reducing the total amount of water the reservoir can hold.
As of Monday, Lake Powell was about 25% full, according to Burial Bureau data.
Bad news for areas already facing water shortages and extreme wildfires due to droughts. Drought experts at the National Oceanic and Atmospheric Administration said last week that these conditions are expected to continue, if at least not worsen, in the coming months.
Lake Powell is an important reservoir in the Colorado River Basin. Lake Powell and nearby Lake Mead, a nearby reservoir, are ejecting at an incredible rate. In August, the federal government declared the Colorado River water shortage for the first time after Lake Mead's water levels plummeted to unprecedented lows, causing forced water consumption cuts in the southwestern state that began in January.
And last week, Lake Powell fell below the critical threshold of 3,525 feet above sea level, sparking additional concerns about millions of water supply and hydroelectric power generation, where millions of people in the West rely on electricity.
The importance of declining water supply along Colorado cannot be overstated.
The system supplies water to more than 40 million people living in seven western states and Mexico. Lake Powell and Mead provide a critical supply of drinking water and irrigation to many people across the region, including rural farms, ranches and native communities.
“It is very important that the best scientific information, like this report, provides a clear understanding of the availability of Lake Powell's water and science,” Tanya Trujillo, deputy secretary for water and science at the U.S. Department of Interior, said in a statement. “The Colorado River System faces multiple challenges, including the impact of 22 years of drought and the increased impact of climate change.”