Satellite photos show water levels in Lake Mead dangerously low

In 2000, Lake Mead was full of deep, dark blue water that flooded the banks of the rivers that fed it. But after 20 years, it has declined sharply. And its basins are also lighter, almost turquoise in places, a sign of increasingly shallow water, connected by unusually thin canyons.

In new images this month, the lake is now surrounded by a wrinkled shoreline and a white shadow, the so-called bath ring, salt and mineral residue left on the canyon walls by receding water.

“These reservoirs were staggeringly full 20 years ago,” said Jennifer Pitt, director of the National Audubon Society’s Colorado River Program, referring to Lake Mead and Powell, two large reservoirs on the Colorado River. Low levels in Lake Mead are indicative of dangerously low levels throughout the Colorado River basin. The pool is now “being dangerously close to a zero-day situation,” Ms said. Pitt said, referring to the moment when the reservoir dries up.

Satellite imagery highlights how severe the drought has become in the southwest. Lake Mead, the largest reservoir in the United States, is an important source of water for 25 million people in seven states, as well as some of the nation’s largest agricultural valleys.

In response to the growing crisis, the federal government has taken steps to conserve water in the Colorado River basin. last summer, the federal government announced a water shortage for the first time at Lake Mead. In June, in response to deteriorating conditions, the Bureau of Reclamation, which manages water and energy resources in the West, issued an emergency request states to propose immediate cuts for 2023 to prevent further falls in reservoirs.

Images taken by the NASA Landsat program in 2000 and 2022 show the driest 20-year period since 800 AD. recent analysis of tree ring data.

Researchers have determined that human-induced global warming has played a role in the continuation of the current drought, which persists despite several years of good rainfall over the past two decades. One reason for this may be that rising temperatures, not rain and snow, are causing this drought.

The Lake Mead images are “a stark illustration of climate change and a prolonged drought that could be the worst in the western United States in 12 centuries,” NASA says. wrote in a statement accompanying images.

The lake is only 27 percent full, the lowest level since the reservoir was filled in 1937. Pitt warned that the available water supply downstream was much lower due to the “dead pool” that occurs when the water level in a reservoir is too low to pass through dams.

The Bureau of Reclamation said that in the two decades that separate these images, the lake’s water level, as measured at Hoover Dam, dropped 158 feet to 1,041 feet. The lake level must remain above 1,000 feet to keep the dam’s water turbines running.

Typically, the reservoir is replenished by snowmelt in the Rocky Mountains flowing into the watershed of the Colorado River. But the snow cover this year was below average.

Henry Fountain made a report.