While the impact of higher temperatures on rivers and reservoirs is widely studied, it’s trickier to know how massive changes in vegetation patterns and landscapes will affect water supplies, now and in the future. It’s likely that the impact of wildfires, drought, and forest die-offs are “much more significant” than warming temperatures alone. That’s according to Richard Middleton, a scientist at Los Alamos National Laboratories (LANL).
Often, people think about climate change as something that’s still 50 years away, but Middleton says it’s a much shorter-term problem. And in some ways, New Mexico is the “canary in the coal mine.”
“We see things happening in New Mexico now, and these are the kinds of things Colorado will be seeing a decade or two in the future,” he says, pointing to the changing snowpack and tree die-offs. “I’m not minimizing the importance to New Mexico, but when you take it up to the Colorado River Basin, that’s a much bigger area, and you’ll also see Las Vegas and California being impacted.”
The first thing to note about Middleton is how excited he is to talk about his work at LANL—a place not exactly known for media friendliness. The second is that he’s earned three Geography degrees over the course of his career. Again, he’s not the guy you’d expect to be working at a nuclear weapons laboratory.
But in recent years, scientists associated with the lab have been studying climate change. They’re motivated in part by obvious impacts all around the lab. Already, the Jemez Mountains are experiencing warmer temperatures, as well as “climate-driven disturbances,” such as bigger wildfires, insect outbreaks, forest die-backs, and drought.
Speaking over the phone while walking me through a powerpoint presentation, he explains that he and his team are halfway through a three-year, $3 million project that draws on earlier studies to understand how those disturbances affect ecosystems and water supplies. Already, their research shows that climate-driven disturbances could reduce annual flows in parts of the Colorado River Basin by 20 percent. It also shows that these disturbances will have “an increasingly catastrophic impact” on regional water supplies.
As part of the project, Middleton’s team is looking at existing data—related to things like vegetation patterns, drought, forest mortality, and streamflows—then using it to develop models that can show what might happen on different scales, ranging from a local hillside to an entire river basin.
Initially, the team focused on a local area and watershed. The second part of the project will take a closer look at regional water supplies, and specifically, at the San Juan River, which provides about 15 percent of the Colorado River’s total streamflow.
The Colorado River Basin supplies drinking water to more than 30 million people and irrigation water for about 15 percent of the nation’s crops and livestock. Its waters also generate electricity, including for coal-fired power plants operated by Public Service Company of New Mexico (PNM) and Arizona Public Service Company.
Albuquerque and Santa Fe both rely on water that’s piped from the San Juan into the Chama River, a tributary of the Rio Grande.
For Middleton, it’s important to understand how the impacts of climate change are going to affect society: “I think it’s good for people to know and understand that because of higher temperatures and other things, our landscapes might look very different from how we’re used to seeing them—and that is going to have an impact on day-to-day life.”
Their work will be submitted to the peer-reviewed journal, Nature Climate Change. But it’s not just an academic exercise. The data should help water managers and energy companies better plan for short- and long-term water supplies. It also has local applications, which Middleton hopes will help other agencies, partners, and nonprofits working on a variety of issues, including forest health and fire.
Cutting back overgrown forests is an important management tool for preventing wildfires. But as their research shines a light on how stream systems respond to changes in vegetation, choosing where to cut and which strategies to employ may mean balancing tradeoffs between managing fires and managing short- and long-term water supplies.
“One of the questions we want to get at has to do with a good thinning routine for fire and what does that make the ecosystem look like in terms of hydrology?” says Middleton. “For our sites up here at Los Alamos, (we could ask) how it might look if you thinned trees in riverbeds in the canyon? That might have a big impact on stopping the fire, but it would be the worst place from a hydrologic perspective to be thinning the trees.”