A damp winter season in western states supplied a short-term reprieve to the decades-long dry spell in the tank.
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 summertime of 2023. Above-average snowmelt from the Rocky Mountains offered some short-term relief to the tank, however long-lasting dry spell stays.
The images above program parts of Lake Powell, which straddles the border of Utah and Arizona, since 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 simply 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 River’s Role
The Colorado River feeds Lake Powell and Lake Mead further downstream. The majority of the river basin is dry or semi-arid and usually gets less than 10 inches (25 centimeters) of rainfall annually. Handled by the U.S. Bureau of Reclamation (USBR) and other firms, the river offers water and electrical power to approximately 40 million individuals– 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.
Rainfall 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 rainfall in the Colorado River Basin remained frozen at high elevations of the Rocky Mountains, avoiding it from going into Lake Powell. On April 13, water in the lake fell simply listed below 3,520 feet, its least expensive level given that the tank was completed 1980.
As temperature levels increased in spring and summertime, above-average overflow from the Rockies supplied a much-needed reprieve. The quantity of water kept in the tank increased from 22 percent complete in April to about 40 percent complete in early July.
Long-Term Drought Challenges
It will take much more than one damp year to fill up the tank to “complete swimming pool” (elevation 3,700 feet). 20 years 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 possibilities of the tank falling listed below the crucial elevation of 3,490 feet. This elevation, referred to as the “minimum power swimming pool,” is the level listed below which water can no longer stream through the consumption valves in the dam to create hydroelectric power. USBR cautioned that water levels had a 57 percent possibility of dropping to listed below the minimum power swimming pool before 2026. Due to the fact that of above-average overflow in the spring and summer season, USBR modified these price quotes in October 2023. They discovered that the opportunity of the tank dipping to this elevation through 2026 had actually been up to 8 percent.
The effect declaration kept in mind that although there is year-to-year variation in circulation in the Colorado River and its tributaries, the basin is still in an extended duration of aridification brought on by environment modification. Dry spell and low overflow from 2000 to 2022 have actually caused “the driest 23-year duration in more than a century and among the driest durations in the last 1,200 years.”
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” data-gt-translate-attributes=”[“characteristic”:”data-cmtooltip””format”:”html”]> NASA Earth Observatory images by Michala Garrison, utilizing Landsat information from the U.S. Geological Survey and lake elevation information from the Bureau of Reclamation.