The Bureau of Reclamation has issued its August 24-Month Study, which determined that the Lower Colorado River Basin will continue to be in a Tier 1 shortage for 2026. Despite a below-average runoff year, and less water flowing into Lake Mead from Lake Powell, the Lower Basin has avoided deeper reductions due to extraordinary actions to reduce water use by parties in Arizona, California, Nevada and Mexico.
The Lower Basin has been voluntarily conserving water in Lake Mead since at least 2014:
- Mechanisms such as Intentionally Created Surplus and System Conservation;
- Mandatory 2007 Interim Guideline reductions and Drought Contingency Plan contributions that have been in place since 2020; and,
- A combination of both mandatory reductions and voluntary conservation, both compensated and uncompensated
In 2023, Lower Basin Colorado River consumptive use was the lowest since 1983. This trend has continued into 2024 and 2025 with Arizona reducing its use by nearly 30 percent. Mandatory and voluntary conservation in 2024 was 873,662 acre-feet and thus far in 2025 it’s 867,216 acre-feet.
These additional actions were pursuant to the 2024 Supplemental Environmental Impact Statement (SEIS), which was prepared to address the particularly low system conditions as of 2022. Collective actions taken in the Lower Basin have temporarily stabilized Lake Mead. In all, Arizona’s contributions to Lake Mead have exceeded 5.5 million acre-feet since 2014, as shown on our Colorado River Dashboard.
“In addition to other conservation measures, the Lower Basin States, Mexico, and CAP water users will be taking significant reductions to help protect the Colorado River in 2026,” says CAP General Manager Brenda Burman. “It’s not easy, but we must remain committed to protecting the river.”
Over the past five years, Lake Powell has released an average of 7.75 million acre-feet. Yet, Lake Powell is still vulnerable because its elevation is reliant on annual runoff, which has been below average, and the consumptive use in the Upper Basin, which has been increasing.
“Today Reclamation announced a release volume that may change. A release of at least 7.48 million acre-feet next year will help ensure that river operations remain in compliance with the Colorado River Compact while we continue to negotiate post-2026 operational guidelines,” says Burman.
The SEIS also contemplates reduction of Lake Powell releases to not less than 6 million acre-feet to protect Lake Powell’s elevation under certain conditions. Before reducing Lake Powell releases, we expect Reclamation will consider all available tools, including additional releases from reservoirs upstream of Lake Powell.
As of the August 24 Month minimum probable study, Lake Powell is projected to reach elevation 3,500’ as early as April 2026. This has triggered a process to finalize a draft Drought Response Operations Plan for releases from Flaming Gorge, Aspinall or the Navajo reservoirs.