SOPHIE BUSHWICK: This is Science Friday. I’m Sophie Bushwick.

KATHLEEN DAVIS: And I’m Kathleen Davis. And now it’s time to check in on the state of science.

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KATHLEEN DAVIS: Local science stories of national significance. As we’ve talked about on this show, the West is in the midst of a water crisis. So we’re going to take a little field trip to Lake Mead, which is the nation’s largest reservoir. It plays a key role in the Colorado River system. And the effects of drought are obvious. There’s a big, white ring along the edges of the reservoir. It’s known locally as the bathtub ring. It’s roughly 160 feet above the current water level. It’s a stark reminder of where water used to be.

Reporter Luke Runyon has been taking an in-depth look at how Southwest states, tribes, and individuals are dealing with this water shortage. It’s a tale of climate change, bureaucracy, and learning to live with less. Luke is host and producer of Thirst Gap, Learning to Live With Less on the Colorado River, a new podcast from KUNC Public Radio. He’s based in Grand Junction, Colorado. Luke, welcome back to Science Friday.

LUKE RUNYON: Hey. Thanks so much for having me.

KATHLEEN DAVIS: So let’s start by getting to know this Colorado River watershed. So imagine a little drop of water. Where does it start its journey before getting into, let’s say, Lake Mead?

LUKE RUNYON: Well, the river begins high up in the Rocky Mountains, where snow piles up each winter. That snow in the mountains of Colorado, Wyoming, and Utah just sits there until springtime when the sun gets high enough in the sky, and it warms up enough to melt it all. And that’s happening right now. We’re in runoff season. And all that snow melts, it rushes into the river, and it’s such a fun time of year. But what we do know is that less water is ending up in the river throughout the year mostly due to rising temperatures from climate change.

KATHLEEN DAVIS: Is it possible to know just how much water has dried up from the Colorado River?

LUKE RUNYON: A lot of the measurements are long-term averages, so it’s tough to put a specific volume on how much we’re losing. Some studies have put it at 20% to 30% of the river’s total volume, with a significant cause of that loss being warming temperatures. What we can say, according to all of the climate science, is that the river is getting smaller, and that’s happening on a few fronts. The warming temperatures are causing more precipitation to fall as rain instead of snow, which is harder to capture and manage, and the higher temperatures are also speeding up how fast water evaporates.

KATHLEEN DAVIS: So let’s get into– there’s this bureaucratic nightmare that’s at the heart of all of this, and that’s the Colorado River compact, which is now a century old, happy birthday. What is the story of this agreement?

LUKE RUNYON: Well, agreement itself was signed in 1922, but to understand why it came together, you have to go back a bit further to around the turn of the 20th century. Around that time, white settlers were moving into the Southwest in greater numbers. They started agricultural communities in Southern Arizona and California, and these farm towns relied really heavily on the Colorado River. But the settlers thought of the river as this unreliable menace. It caused flooding in the spring, and then it nearly dried up in the fall and winter. In my podcast, first episode, I talk about this with Eric Kuhn. He wrote the book Science be Damned about the compact negotiations.

ERIC KUHN: And it created a political movement to control the river, if you want to call it, control this wild, raging river. And at the same time, Southern California was developing, and we were electrifying the nation. So there was a need for power generation.

LUKE RUNYON: People in California started to think that a big dam on the river would solve their problems. It would control the river, generate electricity, and store water for later, and that’s really what pushed the seven states that rely on the river, that’s Colorado, Utah, Wyoming, New Mexico, Nevada, California, and Arizona, to the negotiating table, was this desire to build Hoover Dam. And they all got together to figure out a way to divide the river’s water amongst themselves.

KATHLEEN DAVIS: So who was at the table during this decision making process and who was not?

LUKE RUNYON: Well at the table, you had representatives from the seven southwestern states and the federal government, but not at the table was pretty much everyone else. There was no one from any Native American tribes, and that exclusion of tribal voices lasted for decades after. And even now, tribes don’t have an equal seat at the negotiating table. No one was representing Mexico, which also relies on the river. No one was advocating for the environment. And Eric Kuhn says everyone in the room was basically a politician, an engineer, or a lawyer.

ERIC KUHN: Stream flows, recreation, fishing, no one had that in mind. That attitude was unanimous.

KATHLEEN DAVIS: Without those different voices, was this kind of doomed to fail?

LUKE RUNYON: Well, we were definitely doomed to be short on water. That’s one thing that almost everyone agrees on here. The compact put a number on paper of how much water the Colorado River would provide, and that’s just not how rivers function, especially rivers in the West. There was no way that the Colorado River was going to meet everyone’s needs. It was overallocated right from the very beginning, which means we would be having this problem even without climate change. But climate change is speeding it up, and we’re having to confront this problem sooner than we’d like to.

KATHLEEN DAVIS: All right. Outside of the seven states that are part of this agreement, Southwest tribes do hold some rights to a percentage of the Colorado River’s water, but how has that really played out in reality?

LUKE RUNYON: It’s a big, broad landscape when it comes to tribal water rights. There are 30 federally recognized tribes in the watershed, and they’re all different. Some tribes have water rights that have been fully settled, and in some cases actually leasing their water off of tribal land, but in lots of other cases, tribes do not have their water rights settled. Meaning that they have a certain amount of water that’s been promised to them, but they haven’t had the resources to actually use that water. So it’s a bit of a mix.

One thing that we do know is that tribes collectively hold rights to about 20% of the river’s total amount of water. They’re just not using it all right now. And there’s lots of questions about what it’s going to take to make sure that tribes are included in all future talks over the river, and that they’re meaningfully included, not just a box to be checked in the process.

KATHLEEN DAVIS: So this brings us to modern times. How is this negotiation for water going?

LUKE RUNYON: It’s a pretty tense moment on the river. Last summer, things were looking really dire for the Colorado River. Like the loss of hydropower at one of its biggest dams seemed possible, if not likely. So in response to that, the federal government, which manages the river’s big dams, they threw down this gauntlet for the states. They asked for huge cuts to how much water was being used to stabilize the system. The states came up with these proposals on how to do that, and basically they differ in how water cuts should be dished out, basically, who should feel the burden of water scarcity? Should it hit California or Arizona or Nevada or Mexico the hardest?

Recently, the federal government put forward its own proposals, and those are up for public comment right now. And really what the federal government is doing is weighing how involved it wants to get in Colorado River management. But everyone got a bit more time to negotiate this year because we had a very wet winter, and all that snow eases some of the pressure on the decision makers.

KATHLEEN DAVIS: There’s one city that I want to talk about that is not known for restraint, but it has become somewhat of a model for tightening water use, and that’s Las Vegas. Can you tell me what’s going on here?

LUKE RUNYON: Yeah. Las Vegas is a really interesting example of how big cities are grappling with a limited water supply. I focus on it in episode four of the podcast, and that one comes out on May 8. Nevada has the lowest allocation of Colorado River water. So they’ve had to make do with a lot less water than Arizona or California. And to live within that smaller supply, the city and its main water utility have instituted some of the most aggressive conservation measures in the Southwest.

Within the last couple of years, they’ve made some ornamental grass illegal and are actually forcing its removal. I was there last fall, and I met with Kurtis Hyde. He’s a landscaper in Las Vegas and is doing a lot of these lawn removals. And he says people are slowly coming around to the idea of trading out their grass for desert landscaping.

KURTIS HYDE: I think when people think of zero escape, they think of the old white ugly rock with lava rock and a wagon wheel and a cow skull and three cactus. It is a mindset change where there’s people who prior to this mandate, there’d be HOAs who would literally say, we’ve gotten rid of some grass, and we’re keeping every blade that we have left, and they’ll get pretty emotional about it.

KATHLEEN DAVIS: Is this tactic by the city of Las Vegas working, would you say?

LUKE RUNYON: It’s working for Las Vegas. They’re quick to say that these conservation efforts have enabled the city to grow in population while using less water in the process. So since 2002, they’ve added about 750,000 new residents. Meanwhile, they’re using about 26% less Colorado River water than they were back then, and much of that has been this focus on scaling back outdoor water use.

KATHLEEN DAVIS: Could this be a strategy for other cities, this Las Vegas model?

LUKE RUNYON: It could. There’s a lot of cities in the West that don’t have many programs for dealing with outdoor water conservation. Vegas has been very aggressive, but other cities haven’t necessarily felt that same sense of urgency. And some city leaders, I think, find it really uncomfortable to be dictating what kinds of landscaping people can have and can’t have.

KATHLEEN DAVIS: Of course, people depend on the Colorado River, that is the point of this whole conversation, but what about other creatures? How is this ecosystem around the river changing with less water?

LUKE RUNYON: The ecological impacts here are huge. We had three dry years in a row where river flows were way down. I know here in Colorado, where I live, rivers up high in the mountains were getting so warm that fish were getting too stressed and dying in large numbers.

KATHLEEN DAVIS: Wow.

LUKE RUNYON: The lack of water also contributes to the prevalence of wildfires.

KATHLEEN DAVIS: Who else did you talk to for this huge reporting project?

LUKE RUNYON: I really tried to center the series around this idea that the big overarching solution to the Southwest’s water woes is using less. That’s what I hear when I talk to scientists and water managers. We are going to have to live within what the river provides to us. And that’s incredibly difficult because we’ve created a ton of demand for water in the Southwest, but that is really the way forward here. And so I spend much of the series visiting with people who are already doing that, already adapting to the scarcity, to see what we might all glean from their experience.

KATHLEEN DAVIS: Luke Runyon is host and producer of Thirst Gap, Learning to Live With Less on the Colorado River, which is a new podcast from KUNC Public Radio. He’s based in Grand Junction, Colorado. Thanks so much, Luke, for joining me.

LUKE RUNYON: Hey. Thanks for having me.

KATHLEEN DAVIS: And you can check out Thirst Gap wherever you get your podcasts or at kunc.org/thirstgap.

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