The U.S. Bureau of Reclamation announced last week that two states plus Mexico will have a reduced supply of water for 2023 as the Colorado River basin enters a Tier 2 shortage for the first time in its recorded history.

The effort to conserve water comes as water levels in two of the river’s largest reservoirs – Lake Mead and Lake Powell – reach historic lows, stoking concerns about their respective dams’ ability to provide power. Meanwhile, roughly 40 million people in seven states rely on the Colorado River for water.

The latest federal restrictions were made official Aug. 16 after the states that use the Colorado River failed to reach an agreement about how to reduce consumption in the long-term. Those conversations will continue – and could lead to changes to the 100-year-old Colorado River Compact.

Related: States shirked 'meaningful' action on Colo. River

“We’re almost to the breaking point where someone will have to suggest that the compact needs to be looked at, or all the states involved will have to decide, ‘we need to adjust our water usage every year because there’s no more water coming down the basin,’” said John Tracy, the director of the Colorado Water Center. “That’s the reality.”

He spoke to CSU’s SOURCE about what the latest restrictions mean, what will happen next and Colorado State University’s role in researching water in the West. Read the full Q&A below:

What’s the significance of the Bureau of Reclamation declaring the current situation on the Colorado River a Tier 2 shortage, and why should we care?

There are a lot of different economies on the Colorado River that have been predicated on diverting water and carrying it long distances to cities, industries and agricultural production facilities. That’s been going on for 100 years.

If all of a sudden that water were shut off, it would be bad news for the region’s water supply. The most obvious city in that basin that would be impacted is Las Vegas, but there are other communities that would also have problems.

Being able to have certainty about how much water is available allows a wide range of communities and economic centers to prepare and work to allocate water resources between cities and for industries.

On top of that, the Colorado River is a huge power producer, so making sure the hydroelectric turbines keep flowing in the basin is a big deal. If the water levels drop below a certain point and are unable to produce power, there are cities like Las Vegas that simply can’t operate.

Other states

The U.S. government is reducing the water supply for Nevada, Arizona and Mexico. What does the crisis mean for the state of Colorado?

This gets into an interesting question, because in the U.S., the Constitution leaves decisions on water management up to individual states. The Colorado River Compact set the rules for who gets water when.

Where the federal government became involved is with the dams, and the two really big ones on the Colorado River are the Hoover Dam and the Glen Canyon Dam. Both are downstream from Colorado, so the decisions about reductions in releases there won’t have much of an impact here.

The only thing that might have some impact are instances where individual diverters enter into voluntary agreements to let water go downstream.

What can the federal government do to fix the situation?

Reclamation only has the authority to manage the facilities that they own, and that’s the Colorado River reservoirs. They can’t tell a state or irrigation district what to do. They can enter into agreements with water users, or can reduce releases from their facilities, but they have no regulatory authority on individual water users.

That’s why it’s up to the states to negotiate, and the document the Bureau of Reclamation released on Tuesday essentially says, “we’re going to punt this to next year and hope for a wet winter.”

It’s not the major cutback that’s needed. Instead, it’s trying to bring the lower states back into the allocations that were originally agreed upon by the Colorado River Compact 100 years ago. The federal government is hoping to get people to live by the agreement, and is hoping for a wet winter that will make the situation less urgent.

Related: There's a crisis on the Colorado River

With climate change and the record drought, is there time to wait for a wet winter?

It’s one of those situations where you look at it via basic numbers. In essence, the Colorado River Compact from 100 years ago was predicated on a whole lot more water being available in the river than what really exists.

Climate change has made this worse and the timing worse, and it’s something we’ll have to live with in the future. So, you either do something really big, dealing with multiple states and the politics and interest groups involved, or you do year-to-year adjustments and see what happens.

 What happens if no action is taken? 

The solution will put itself into place. Reclamation has an obligation to keep the hydropower going for the electric grid, and if we don’t have a good winter and the water levels continue to drop, they’ll be in a position where they’ll have to reduce flows to the lower states.

It will be up to the U.S. Bureau of Reclamation to choose to either reduce hydropower production or the allocations to the lower states, because there will be no water to allocate.

This year, the Bureau said, “we can manage, but we’re right on the cusp.” But if the situation worsens, no action will not be a possibility and decisions will have to be made.

What's the CWC doing?

How is the Colorado Water Center furthering the scientific understanding of what’s happening in the Colorado River Basin?

There are various elements to it. You have Senior Water and Climate Scientist Brad Udall researching the climate change impacts on the Colorado River and beyond, and he has been providing very insightful basic science to inform policymakers about what they’ll have to deal with.

He’s been very important in moving this discussion forward to the point that it’s clear a crisis is coming.

Senior Water Policy Scholar Jennifer Gimbel is working to educate people on the Colorado River, and not just the physical nature, but how it impacts the seven states that utilize it. She’s teaching a graduate-level seminar course (GRAD 592) this semester focusing on the Colorado River Basin.

Research Scientist and Extension Specialist Perry Cabot is calculating water usage, and specifically helping policymakers understand how much water is utilized by crops and how much returns to rivers. He’s been collaborating with a wide variety of scientists across the West.

The Colorado Water Center is also doing lots of work to help policymakers understand the physical situation of the Colorado River, the history of the Compact, the water use in the basin and the science behind the drought’s impact.

What we don’t do is get into the discussion of where any agreement should go. We’re at the point where something’s got to give, and it will be interesting to see what happens, but that’s up to the policymakers and federal agencies responsible for the river.

To put it succinctly, our role is understanding the science and making sure everybody’s educated on the science.

Source: Colorado State University, which is solely responsible for the information provided and is wholly owned by the source. Informa Business Media and all its subsidiaries are not responsible for any of the content contained in this information asset.