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- Colorado River Shortage
ARIZONA - STRONGER TOGETHER
The Colorado River Basin continues to experience drought exacerbated by the impacts of climate change. For 2022, the U.S. Secretary of the Interior declared the first-ever Tier 1 shortage for Colorado River operations. This Tier 1 shortage has resulted in a substantial cut to Arizona’s share of the Colorado River – about 30% of Central Arizona Project’s normal supply; nearly 18% of Arizona’s total Colorado River supply; and less than 8% of Arizona’s total water use. Nearly all the reductions within Arizona have been taken by Central Arizona Project (CAP) water users. These reductions were determined by the CAP priority system – the result being less available Colorado River water for central Arizona agricultural users. Current projections point to Tier 2 shortage operations in 2023, which will equate to reductions in the supplies available to municipal/industrial and tribal water users.
Shortage Impacts
Joint ADWR/CAP press release regarding the U.S. Secretary of the Interior’s declaration of a Tier 1 shortage on the Colorado River for 2022
2022 Tier 1 Colorado River shortage fact sheet
Lake Mead August 2021 24-Month Study infographic
Colorado River shortage will have various impacts on available water supply to CAP water users.

Media Statements
- Joint ADWR/CAP Opinion Piece (Arizona Republic, Sunday, May 8) — Colorado River under stress – Arizona’s response
- Joint ADWR/CAP press release regarding the U.S. Secretary of the Interior’s declaration of a Tier 1 shortage on the Colorado River for 2022
- April 24 Month Study joint statement
- Arizona’s shortage preparedness joint statement
More Information
- Arizona heads into Tier 1 Colorado River Shortage for 2022
- Why do water managers pay such close attention to the 24-Month Study?
- CAP Priority System
- Lake Mead – 2021 Tier Zero Operations
- Hydrologic Modeling
- Lake Mead/Lake Powell Operations – Conjunctive Management
- August 2020 24-Month Study
- Colorado River Basin Climate and Hydrology State of the Science Report
- Lake Mead – 2020 Tier Zero Operations