Need To Know

CAP Prepares for Tier 2a Colorado River Shortage in 2023

Colorado River at Dusk

The Lower Colorado River Basin will be in the first-ever Tier 2a shortage beginning Jan. 1, 2023. Here’s what you need to know:

  • For Arizona, a Tier 2a shortage represents a 592,000 acre-foot reduction to the state’s Colorado River supply. This equates to 34% of Central Arizona Project’s normal supply in an average year, 21% of Arizona’s Colorado River supply and about 9% of Arizona’s total water use.
  • For CAP water users, this means there is no longer Colorado River water available for the Excess Water and Agricultural pools. The Tier 2a shortage will mean a 3% reduction to Municipal & Industrial supplies and a 7% reduction to Tribal supplies. See our infographic below for a graphical representation of the effect on CAP supplies.
  • Current hydrologic modeling indicates the Colorado River Basin will be in deeper levels of shortage in the coming years.

The Tier 2a shortage is certain for 2023. But more will need to be done to stabilize critical levels at the Colorado River Basin’s two main reservoirs – Lake Powell and Lake Mead. The Bureau of Reclamation is considering additional protection measures, which have yet to be announced. Any additional reductions would be on top of the Tier 2a shortage.

Stay up to date by frequently visiting the River Updates section on Know Your Water News. This includes our updated Shortage FAQ and a new fact sheet on Shortage Milestones that will give you more background on the Law of the River components that have led us to this point.

Tier 2a. Shortage 2023 Infographic

ADWR and CAP update Arizona Reconsultation Committee on current status of Colorado River issues

River Update Graphic

The Arizona Reconsultation Committee (ARC) reconvened on Friday, Nov. 4 for an update on current Colorado River conditions. The presentation is here and the video is here. Although the Lower Colorado River Basin will be in a Tier 2a shortage for 2023, it is likely that additional reductions will be necessary to protect critical levels in Lakes Powell and Mead.

The 2007 Interim Guidelines for the coordinated operation of Lakes Powell and Mead are set to expire at the end of 2026. The formal reconsultation process is expected to begin in 2023. The Colorado River Basin states will play a leading role in developing these new guidelines. The Arizona Department of Water Resources and Central Arizona Project convened the ARC to provide input on Arizona’s participation and path forward in this process.

Download deck – HERE

Watch Video –