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Science and Innovations

Water Experts Warn Of Colorado River’s Limits

National Park Service, Lake Mead National Recreation Area

Diminishing aquifers, drying rivers, and lingering droughts are the headlines in the West this year. Experts in science and policy say it’s urgent Arizonans plan for a future with much less water. KNAU’s Melissa Sevigny spoke with John Fleck of the University of New Mexico’s Water Resources Program about how warnings about the Colorado River’s limits have been ringing out for more than a century.   

So let’s do some history first. When did hydrologists first start warning people that the Colorado River didn’t have as much water as they wanted it to have?

This goes all the way back to the early 20th century when we were first planning dams and canals for the farms and the cities, and there were hydrologists who warned that the Colorado River was subject to some really deep droughts that could last a long time. The work was generally ignored in favor of more optimistic estimates that allowed us to build bigger dams and bigger cities and larger farming communities. The science was inconvenient, so it was shoved aside, as we have often seen happen with the history of water in the Western United States.

Fast forward to today, what’s the water situation right now on the Colorado River?

This has been a particularly bad year, and a really eye-opening year. The reservoirs are dropping, Lake Powell and Lake Mead are at the lowest levels or headed toward the lowest levels since we first built them and starting filling them. What’s happening is because of climate change, because of warming temperatures, we’re getting less water in the river. You get a halfway decent snowpack like we had this year, and a lot less water ends up in the rivers, you get more evaporation, the plants have a longer growing season, and they’re super happy… but they’re taking up a lot more water…just less water ends up in our reservoirs.

So the river is down 20 percent compared to what it was a century ago, is this our new baseline or do you think it’s going to get worse?

It would be unwise to assume we’re just going to get wet again, because the climate science clearly suggests we’re headed in the drier direction…. How much drier? We don’t know. I think that’s one of the challenges for climate science. But it would not be prudent to not take this seriously and think about what our risks are as some of the more dire climate science scenarios play out.

What exactly does that look like? What should we do?

There’s reason to be optimistic. We have seen across the Western US over the last 15-20 years communities get better at using their water more efficiently…. And we’ve also seen some of the larger farming areas do well with less water. We’re not doing this quickly enough. It means taking the science seriously and everybody recognizing we’re all going to have to do more with less water…. So I think it’s really important that we recognize as we’re figuring out how to deal with smaller allocations, that there are these communities, the Native American communities, who have got left out, and may need more water than they are now getting. They have a legal entitlement but also a moral and ethical entitlement.

That sounds like a pretty big task ahead, learning how to do with less water and also making sure the water is more equitable, how are you feeling about being able to accomplish that?

I think we have to model an optimistic future. Not sure we’re going to get there, but I think we need to show what an optimistic positive path looks like, in order to help people doing these very difficult negotiations that are going to go on over the next few years… When we had these problems in our decision-making processes a century ago, it was a problem in the future. It was a potential problem in the future. Those reservoirs are emptying fast, the problem is now. It’s pretty obvious if you go out and look at Lake Mead and Lake Powell that we can’t ignore this anymore.

John Fleck, thank you so much for speaking with me.

Thanks for having me.

Melissa joined KNAU's team in 2015 to report on science, health, and the environment. Her work has appeared nationally on NPR and been featured on Science Friday. She grew up in Tucson, Arizona, where she fell in love with the ecology and geology of the Sonoran desert.
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