CNN
—
Lake Powellthe second-largest man-made reservoir in the US, has lost nearly 7 percent of its potential storage capacity since 1963, when Glen Canyon Dam was built, a new report shows.
In addition to water losses due to a intense multi-year droughtUS Geological Survey and Bureau of Reclamation report foundLake Powell experienced 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 reflecting pool on the National Mall about 1,600 times.
The capacity of the reservoir is reduced due to sediments flowing from 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 it can hold.
As of Monday, Lake Powell was about 25 percent full, according to data from the Bureau of Reclamation.
It’s bad news for a region already dealing with water shortages and extreme fires due to drought. Drought experts at the National Oceanic and Atmospheric Administration said last week that those conditions are expected to continue at least – if it doesn’t get worse – in the coming months.
Lake Powell is an important reservoir in the Colorado River basin. Both 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 since Lake Mead’s water level. plummeted to unprecedented lowstriggering mandatory water cutbacks for southwestern states that began in January.
And last week, Lake Powell sunk below critical threshold of 3,525 feet above sea level, raising further concerns about the water supply and hydropower generation that millions of people in the West rely on for electricity.
The significance of the declining water supply along the Colorado cannot be overstated.
The system supplies water to more than 40 million people living in seven western states and Mexico. Lakes Powell and Mead provide an essential supply of drinking water and irrigation for many throughout the region, including rural farms, ranches and native communities.
“Having the best scientific information available, such as this report, is extremely important 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 impact of climate change.”