MISSOULA – As mountain watersheds store and release water, the Earth’s shape changes ever so subtly. The University of Montana Department of Geosciences now can track those changes by GPS, thanks to a $1.4 million cut of a multi-institutional collaborative award from the National Science Foundation.
The total value of the award, part of the NSF’s Frontier Research in Earth Sciences program, is $2.43 million.
The project is headed by UM Geosciences Assistant Professor Hilary Martens, who has a background in space science, planetary science and geophysics. After earning not one but three prestigious scholarships – the Presidential Leadership, Marshall and Goldwater – at UM, she received masters’ degrees in space science at University College London and volcano seismology at Cambridge.
Martens earned her doctorate in geophysics and geodesy from the California Institute of Technology in 2016, where she used GPS to measure how Earth’s surface depresses and rebounds with cyclical ocean tides. She will apply the same concept to measuring ground deformation in mountain watersheds.
For the new project, the team will use GPS to track changes in the shape of the Earth from the storage and flow of water. GPS receivers can determine sagging of Earth’s surface under the weight of water to the accuracy of 1 mm, and the team will use that information to estimate the total amount of water added or removed from a watershed daily or over a period of years. Martens will process and analyze the GPS data, as well as develop models to predict changes in the Earth’s shape due to the differing water amounts.
“Deepening our understanding of water in mountain watersheds is crucial, because mountain watersheds serve as critical reservoirs of fresh water for human communities and other natural ecosystems worldwide,” Martens said.
Other UM Department of Geosciences researchers on the project include Assistant Professor of Hydrology Payton Gardner, Professor of Geophysics Rebecca Bendick, graduate students Mason Perry and Noah Clayton and postdoctoral scholar Lia Lajoie.
Perry, who will complete a Ph.D. soon, uses GPS to study long-term tectonic deformation and how snow loads influence earthquakes in the Northern Rockies.
“I’ve been lucky to do a lot of field work in my time at UM, and my experience in the field installing and maintaining GPS stations will hopefully allow for the project to get up and running relatively quickly,” Perry said.
He will help with GPS processing in the NSF-funded watershed project.
Zachary Hoylman, a research scientist in UM’s W.A. Franke College of Forestry and Conservation, and Zachary Rossmiller, the executive director for cyberinfrastructure at UM, also will contribute to the project.
The Scripps Institution of Oceanography at the University of California-San Diego and the NASA Jet propulsion Laboratory have teamed up with UM for the project to bring more expertise.
“The project is multi-disciplinary by design to push the boundaries at the frontiers of Earth sciences,” she said. “We have specialists in hydrology, geodesy, meteorology, computer modeling, Earth structure, and water management participating in the project. The project would not be possible without such a diverse team.”
The project investigates three watersheds: the Selway-Lochsa in Montana and Idaho, Russian River in California and the Upper San Joaquin River in California. The team will measure crustal displacement, streamflow, snow depth, precipitation and atmospheric conditions at all locations.
“I’m really excited to see what comes out of this project,” Perry said. “I think GPS has huge potential to monitor hydrologic processes at watershed-size spatial scales, and it’s really exciting to play a role in cutting-edge research that is expanding the capabilities of a tool that I use regularly.”
Martens hopes the information from the project will assist local communities in managing water resources and using GPS to forecast flood and flash drought risks.
“With increasing demands on water resources from human consumption coupled with rapid changes in global climate, new advances in water-resource prediction and management are essential for socioeconomic sustainability and prosperity,” she said.