April 29, 2024

Rising Against the Odds: Remarkable Resurgence of America’s Second Largest Reservoir Amid Persistent Drought

The images above program portions of Lake Powell, which straddles the border of Utah and Arizona, as of October 20, 2023 (right), compared to September 23, 2022 (left). As of November 12, 2023, lake levels stood at 3,572 feet (37 percent complete), which is just listed below the 1991– 2020 average for that date. The Colorado River feeds Lake Powell and Lake Mead farther downstream. On April 13, water in the lake fell simply below 3,520 feet, its lowest level given that the tank was filled in 1980.
Water levels in Lake Powell fell to a record low in 2022 and again in 2023.

Satellite picture of Lake Powell acquired on September 23, 2022, by the Operational Land Imager 2 on Landsat 9.
Satellite image of Lake Powell obtained on October 20, 2023, by the Operational Land Imager on Landsat 8.
A damp winter season in western states provided a short-term reprieve to the decades-long dry spell in the reservoir.
After being up to tape lows in early 2023, water levels in Lake Powell– the second-largest tank in the United States– rebounded in the summer of 2023. Above-average snowmelt from the Rocky Mountains provided some short-term relief to the reservoir, but long-lasting drought stays.
The images above show portions of Lake Powell, which straddles the border of Utah and Arizona, as of October 20, 2023 (right), compared to September 23, 2022 (left). Since November 12, 2023, lake levels stood at 3,572 feet (37 percent complete), which is just listed below the 1991– 2020 average for that date. The 2023 image was gotten with the OLI (Operational Land Imager) on Landsat 8 and the 2022 image was obtained by the OLI-2 on Landsat 9.

The Colorado Rivers Role
The Colorado River feeds Lake Powell and Lake Mead further downstream. Many of the river basin is semi-arid or dry and usually receives less than 10 inches (25 centimeters) of precipitation annually. Managed by the U.S. Bureau of Reclamation (USBR) and other firms, the river supplies water and electric power to roughly 40 million people– most significantly the cities of Las Vegas, Phoenix, Los Angeles, and San Diego– and water to 4 to 5 million acres of farmland in the Southwest.
Precipitation Patterns and Lake Levels
A series of 9 climatic rivers brought considerable quantities of rain and snow to the western U.S. in December 2022 and January 2023. Much of the precipitation in the Colorado River Basin remained frozen at high elevations of the Rocky Mountains, preventing it from entering Lake Powell. On April 13, water in the lake fell simply below 3,520 feet, its lowest level since the tank was completed 1980.
As temperature levels increased in spring and summertime, above-average overflow from the Rockies provided a much-needed reprieve. The quantity of water held in the tank increased from 22 percent full in April to about 40 percent complete in early July.
Water Elevation at Lake Powell in between 1980 and 2023.
Long-Term Drought Challenges
It will take much more than one wet year to fill up the reservoir to “full swimming pool” (elevation 3,700 feet). 2 decades of dry spell in the American Southwest have actually drawn down water in the tank. Water levels in Lake Powell was up to a record low in 2022 and once again in 2023.
In April 2023, USBR launched a draft Environmental Impact Statement for Colorado River Operations, which examined the opportunities of the tank falling below the critical elevation of 3,490 feet. Due to the fact that of above-average overflow in the spring and summertime, USBR modified these price quotes in October 2023.
The effect statement noted that although there is year-to-year variation in flow in the Colorado River and its tributaries, the basin is still in a prolonged period of aridification brought on by climate modification. Drought and low runoff from 2000 to 2022 have actually led to “the driest 23-year period in more than a century and among the driest durations in the last 1,200 years.”
NASA Earth Observatory images by Michala Garrison, using Landsat information from the U.S. Geological Survey and lake elevation data from the Bureau of Reclamation.