Satellite photos show Lake Mead’s water levels are dangerously low

In the year 2000, Lake Mead was awash with deep, midnight blue water that spilled the banks of the rivers that fed it. But 20 years later, it has shrunk drastically. And its pools are lighter, too, almost blue-green in places, a sign of increasingly shallow waters connected by extraordinarily narrow canyons.

In new images this month, the lake is now surrounded by a rippled shoreline and a white shadow known as the bathtub ring, remnants of salts and minerals left on the canyon walls by receding water.

“Those reservoirs were amazingly full 20 years ago,” said Jennifer Pitt, Colorado River program director for the National Audubon Society, referring to Lake Mead and Lake Powell, the two large reservoirs on the Colorado River. The low levels at Lake Mead indicate dangerously low levels throughout the Colorado River drainage basin. Now the basin is “dangerously close to a day zero situation,” Ms Pitt said, referring to the point at which the reservoir is drying up.

The satellite images underscore how acute the drought has become in the southwest. Lake Mead, the largest reservoir in the United States, is a vital source of water for 25 million people in seven states and some of the country’s largest agricultural valleys.

In response to the growing crisis, the federal government has taken steps to conserve water in the Colorado River drainage basin. Last summer, the federal government declared a water shortage at Lake Mead for the first time. In response to worsening conditions, the Bureau of Reclamation, which manages water and power in the west, issued an emergency request to states in June to propose immediate cuts for 2023 to prevent reservoirs from sinking further.

The images, captured by NASA’s Landsat program in 2000 and 2022, show the driest two decades since AD ​​800, according to a recent analysis of tree ring data.

Researchers have determined that human-caused global warming has played a role in the continuation of this current drought, which has persisted despite a few years of good rainfall over the past two decades. One reason could be that rising temperatures are driving this drought more than rain and snow.

The Lake Mead images provide “a stark illustration of climate change and a long-term drought that may be the western United States’ worst in 12 centuries,” NASA wrote in a statement accompanying the images.

The lake is only 27 percent full, the lowest level since the reservoir was filled in 1937. But Ms Pitt warned that the available water supply is much less downstream because the “dead pool” occurs when there is also water in the lake Reservoir located low to pass the dams.

In the two decades separating these images, the lake’s water level as measured at Hoover Dam has fallen 158 feet to 1,041 feet, the Bureau of Reclamation said. The lake level must remain above 1,000 feet to continue operating the dam’s hydroelectric turbines.

Normally, the reservoir is filled by snowmelt in the Rocky Mountains, which flows into the Colorado River watershed. But the snow cover was below average this year.

Heinrich Brunnen contributed reporting.

Leave a Comment

Your email address will not be published.