Tier 1 Shortage announced for 2025, but more must be done for the Colorado River

Last week, the Bureau of Reclamation released its August 24-Month Study , which is projecting that the Colorado River will remain in a Tier 1 Shortage for 2025.

“The Colorado River System is already showing significant improvements as a result of water savings from the historic investments in conservation and infrastructure improvements through the Bipartisan Infrastructure Law and Inflation Reduction Act,” Bureau of Reclamation Commissioner Camille Touton said in a statement .

Touton was referring to the agreements made by Arizona, Nevada, and California to jointly conserve at least 3 million acre-feet of water through 2026. This year, those conservation efforts by the Lower Basin states, along with this winter’s precipitation, improved the short-term outlook for both reservoirs. Lake Powell is roughly at 39% capacity, while Mead is about 33% full, which is positive progress compared to two years ago.

So, while we know we are expected to remain in a Tier 1 Shortage next year, there are still plenty of decisions to be made regarding the Colorado River. Behind the scenes, the seven Basin States who previously submitted dueling Lower Basin vs. Upper Basin proposals continue to try to find a consensus on how the Colorado River will be managed after the current operating guidelines expire at the end of 2026. 

Despite the positive efforts to sustain the river system through 2026, it is important to recognize that no water manager along the Colorado River would consider Lake Mead at 33% full as optimal. Two bad winters in a row could cause the system’s reservoirs to fall to critically low elevations that would threaten water deliveries and power production. The Colorado River is faced with a historic drought and warmer and drier conditions that produce smaller runoffs.  

With a river that is producing less water, Reclamation and the Basin States must find a consensus to reduce demand on a river that is already overallocated. The federal government is expected to issue draft regulations by December that factor in the different plans and propose a way forward for post-2026 operational guidelines. 

Water managers across the Basin understand the overall trajectory of the system is declining and cannot be ignored. That is why they remain focused on finding common ground to provide better certainty for the 40 million people who rely on it. Protecting the Colorado River system through collaborative actions from water users from across the Basin must remain the priority.

What is the 24-month Study, and why does it matter?
First and foremost, the 24-month Study is central to how the Colorado River is managed. It is a study, or forecast, of reservoir conditions along the Colorado River for the next 24 months. Its contents can impact the water supplies used by millions of people who rely on the Colorado River, including here in Central Arizona.

The Study is also critical in determining how Lake Powell (behind Glen Canyon Dam) and Lake Mead (behind Hoover Dam) will be operated. The Bureau of Reclamation currently operates both reservoirs in a coordinated, balanced fashion primarily determined by how much water is stored in each reservoir. The level of Lake Powell is affected mainly by runoff generated from snowmelt, which is high in the Rockies. In contrast, the level of Lake Mead, located downstream, is primarily managed by how much water is purposefully released from Lake Powell. 

The April 24-month Study is unique because it gives us our first solid look at spring and summer runoff conditions after the winter season has ended. Based on April’s projection, more or less water may be released from Powell to Mead than previously planned. That change in the amount of water released into Lake Mead will offer a better picture of what to expect in August, when the August 24-month Study will determine what level of shortage will be declared and implemented in January of the following year.

 For 55 years, the Arizona Municipal Water Users Association has helped protect our member cities' ability to provide their communities with assured, safe, and sustainable water supplies. For more information, visit www.amwua.org .