University of New Mexico researchers plan to get better watershed data with $7 million NSF grant

New Mexico’s watersheds are getting a checkup from University of New Mexico researchers, who plan to use a $7 million National Science Foundation grant to better understand how watersheds throughout the state are functioning and the long-term impact of different management decisions.

New Mexico landscapes play a role in drinking water access, biodiversity and capturing carbon from the atmosphere. With more extreme drought and variable rainfall predicted in the state’s future, UNM’s Accelerating Resilience Innovations in Drylands Institute wants to get hard data about watershed health into the hands of people making water management decisions.

“We’re going to increase our understanding of these watersheds, and we’re going to get more of a high-resolution picture of what the actual landscape looks like,” said Marcy Litvak, a UNM biology professor leading the study.

A watershed is an area of land that channels rainfall and melted snow to creeks, streams and rivers.

Researchers will examine 500 priority watersheds in the state to understand the relationship between how those watersheds look and how they function. The priority designations were made by the U.S. Forest Service based on wildfire risk, water source importance and biodiversity.

They will also focus on two specific watersheds, one at the northern end of the state and one in the south. For the first two years of the four-year project, they will study the Santa Fe Watershed, a 180,000-acre watershed that includes the Santa Fe River and all of its streams.

Researchers will look at details like the number, species and density of trees, as well as how much carbon and energy is being exchanged in the environment and how much water is flowing through the river and streams.

“What we’re really interested in is: as the surface of the watershed changes, as what it looks like changes because of climate change, or because of disturbance, because of fire, because of management, how does that then alter the way that the ecosystem or that watershed is actually able to function?” Litvak said.

The Santa Fe Watershed is a good place to start capturing that high-resolution snapshot because it has subbasin areas that have been managed in different ways. Some parts of the watershed have been subject to forest thinning, some to wildfire and some left alone.

“We can actually monitor all of those differences, and then try to put it all together to quantify the differences between them,” Litvak said.

For the second half of the project, researchers will examine a watershed in the Gila Wilderness, although the specific watershed has not been chosen yet.

For the last 20 years, the ARID Institute has already been measuring how much carbon, water and energy are exchanged at nine locations in different kinds of forests.

“It tells us things like how much carbon is stored, how much water does it use and release into the atmosphere, what impact does it have on surface temperature,” Litvak said.

The new study will take those measurements, along with historic photographs and extra climate data, and use machine learning to make estimates for an entire watershed about carbon sequestration, water use, and how much water is going back into aquifers or being released into the atmosphere.

“What this technique allows us to do is to understand how much water is being moved through the ecosystem based on how much water it gets,” Litvak said.

That can provide insights into important questions like how much water will be available to drink and how important these forests are for regulating temperature.

“We want to figure out: what are the management strategies that will promote healthy forests and healthy watersheds so that they can continue to provide the services that sustain us all here in New Mexico,” Litvak said.

The ARID Institute will be working on the study with New Mexico State University, Western New Mexico University, the Asombro Institute for Science Education, UNM’s Bosque Ecosystem Monitoring Program and New Mexico State Forestry.