AMWUA Blog

Aug 09 2021Share

Tier 1 Shortage: What Does it Mean for us Here in Arizona?

By AMWUA Staff

We anticipate a Tier 1 Colorado River Shortage in 2022 will be declared next week with the release of the United States Bureau of Reclamation (BOR)’s August 24-Month study. This Tier 1 Shortage declaration will not come as a surprise. For many years, Arizona water professionals have been anticipating and preparing for this shortage. Now that it is here, what does it mean, and how does it impact Arizona and the AMWUA cities?   

WHAT IS A TIER 1 SHORTAGE ON THE COLORADO RIVER?

The Colorado River supplies water to Arizona, six other western states, and Mexico. Each has a specified amount of water that they are entitled to use every year. When the elevation of Lake Mead is projected in August to fall to 1,075 feet or lower by the end of the current year, the federal government is to declare a Tier 1 Shortage beginning in January. This shortage is a reduction in the amount of water that can be used from the Colorado River and is part of a broader plan to protect the overall health of the Colorado River system.

In 2022, the Colorado River is expected to experience a Tier 1 Shortage, which means that Arizona, Nevada, and Mexico have all agreed to take less water from the River for the year.

WHY IS A TIER 1 SHORTAGE HAPPENING IN 2022?

For the last two decades, the Colorado River Basin has been facing the worst drought in 1,200 years, plus experiencing a warmer climate, stressing the already over-allocated Colorado River. To be proactive and prevent further depletion of Colorado River water supplies, the seven Basin States set operating guidelines to use less water when Lake Mead and Lake Powell drop to specific levels. These Colorado River operating guidelines were established in 2007 and updated again in 2019 by the Drought Contingency Plan (DCP).

In 2022, Lake Mead’s elevation is projected to be below 1,075 feet. This decline in Lake Mead will trigger a Tier 1 Shortage declaration, and therefore, less water will be delivered from the Colorado River.

HOW DOES A TIER 1 SHORTAGE IMPACT ARIZONA?

For Arizona, a Tier 1 Shortage results in an estimated 30% reduction to Colorado River supplies delivered by the Central Arizona Project (CAP) to water users in Maricopa, Pinal, and Pima counties. We have a longstanding priority system that governs who receives Colorado River water in times of shortage. Central Arizona agricultural users have the lowest CAP priority, and therefore will face the brunt of the Tier 1 Shortage reductions. Municipalities and tribes have the highest CAP priority and will not face water reductions in 2022.

To help water users facing reductions during a Tier 1 Shortage, the Arizona DCP Implementation Plan was created in 2019 to provide alternate water supplies and funding to those impacted by the cuts. The AMWUA cities have committed resources to support this plan that includes sending water to Central Arizona farms.

WHAT DOES THE 2022 TIER 1 SHORTAGE MEAN FOR AMWUA CITIES AND RESIDENTS?

A shortage on the Colorado River does not mean there will be a shortage at your tap. AMWUA cities will continue to receive their Colorado River supplies in a Tier 1 Shortage and access other water sources, including Salt & Verde River water, reclaimed water, and groundwater. Therefore, the Tier 1 Shortage will have no immediate impact on your city’s ability to meet the water needs of its customers.

A Tier 1 shortage does mean that municipal water providers will continue to do what they have done for decades. The cities will continue to plan, manage, conserve and invest in their water supplies and infrastructure to ensure they are prepared for any short-term or long-term challenges that may arise. A Colorado River shortage is just one of many scenarios the cities have planned for.


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For over 50 years, the Arizona Municipal Water Users Association has worked to protect our member cities’ ability to provide assured, safe, and sustainable water supplies to their communities. For more water information, visit www.amwua.org.

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