We are recruiting a 2-year research postdoc. See this announcement
Global Rivers Group
@Virginia Tech
We use satellites, models and fieldwork to study Earth's freshwater
We're an academic research group in the Department of Geosciences at Virginia Tech. We are recruiting students and postdocs who are interested in using emerging technology to solve problems involving freshwater resources.
What we do
We study inland waters using satellite data, fieldwork, and computational models. We seek to understand how climate change and land use are altering the water cycle, in particular river and lake hydrology. With rapid advancements in sensor technology, computing power, and model sophistication, it is an exciting time to be studying freshwater at the global scale.
Why we do it
Water is widely considered to be the world’s most vital natural resource, yet freshwater systems are being rapidly degraded by human activities. Our work is motivated by a desire to promote the conservation, management, and understanding of Earth's surface water resources.
News
Updated August 8, 2026
August 10-14, 2026—Hana and George attend the IEEE International Geosciences and Remote Sensing Symposium (IGARSS) in Washington D.C. to present their research and network.
August 5, 2026—Steve, David, Hana, Yohtaro, and George all submit abstracts to AGU 2027, which will take place in San Francisco December 7–11.
July 23, 2026—PhD candidate, Hana Thurman, completes her 10-week research internship at the Jet Propulsion Laboratory in Pasadena, California. We look forward to your return to Blacksburg, Hana!
July 23, 2026—The Global River Group is hiring a 2-year research postdoc associate. Please see this announcement for more information
July 20, 2026—New paper published in Nature Communications entitled, "Human imprints on global riverfronts". Led by Fanxuan Zeng and Chunqiao Song at the Chinese Academy of Sciences, this paper uses commercial satellite imagery to classify land cover types along global rivers and finds that 20% of global riverfronts are anthropogenically modified. https://doi.org/10.1038/s41467-026-75777-0
July 15–16, 2026—The GRG runs a 2-day field trip and workshop for 48 high school students as part of the Virginia Tech College of Science Explore Physical Sciences summer camp program. Day 1 involved hands-on field activities at the confluence of Toms Creek and the New River and Day 2 involved analyzing field data.
July 8, 2026—New paper out in Science Advances entitled "Satellite observations reveal widespread alteration of river thermal regimes by US dams". This study shows that large dams in the United States are causing major thermal disruptions to river temperatures downstream. Led by Emily Ellis, this study demonstrates a new technique to track Earth's changing river thermal conditions. George and former GRG postdoc Katie McQuillan are coauthors: https://doi.org/10.1126/sciadv.aeb5193
June 17, 2026—Review paper published in Nature Water titled "Remote sensing and the new global river science". This team-written review article outlines the rapid development of the methods and products in the field of remote sensing of global rivers: https://doi.org/10.1038/s44221-026-00665-2
June 4, 2026—New paper published in Geophysical Research Letters entitled "From Lotic to Lentic: SWOT Characterizes Seasonal Hydrodynamics in the Lake-River Continuum". Led by Dr. Xinchen He at University of Illinois, this paper shows how the SWOT satellite can measure the complex dynamics of the river-lake transition zone, work that can be applied to coastal regions. George and Katie McQuillan contributed to this paper: https://doi.org/10.1029/2026GL122664
May 18, 2026—Hana travels to Pasadena, CA for a 10-week research internship at the NASA/Caltech Jet Propulsion Laboratory. She will be working with Dr. Cedric David on SWOT, floods, and hydrologic models. Have fun, Hana!
May 4, 2026—Hana receives a graduate research fellowship from the Virginia Space Grant Consortium to support her work on the SWOT satellite. Congratulations, Hana!!
April 28, 2026—Emily Ellis successfully defends her dissertation, "Joining Water Quantity and Water Quality: Assessing Altered River Thermal Regimes with Satellite Remote Sensing". Congratulations, Dr. Ellis! 🎉 Emily will begin a research postdoc with Dr. John Gardner at UNC Chapel Hill this May.
April 24, 2026—George hosts Dr. Michael Durand from Ohio State for the Geosciences Departmental Seminar. The title of his talk is "New insights into the global water cycle: The role and snow and the Surface Water and Ocean Topography satellite mission".
April 11, 2026—NASA Water Quality Applications Program proposal selected for funding. 🎉 This project is titled “Integrating Earth observations into automated water quality forecasts to improve drinking water management” and is led by VT faculty Cayelan Carey, Quinn Thomas, & George Allen.
Mar 30, 2026—David hosts Dr. Ted Langhorst for the Virginia Tech Remote Sensing seminar series. Dr. Langhorst is a postdoc at UMass Amherst using satellites and machine learning to study river networks. The title of his talk is "Model-data fusion approaches for water resources modeling with remote sensing data".
Mar 2, 2026—Steve hosts Dr. Cathleen Jones for the Virginia Tech Remote Sensing seminar series. Dr. Jones is a senior research scientist at JPL and the NISAR satellite mission's Applications Lead. The title of her talk is "NASA’s NISAR Earth Observing Mission: Its Past, Present, and (Hopefully) Future". Bio: https://www.jpl.nasa.gov/site/research/cjones
Mar 19-20, 2026—Yohtaro, Steve, Hana and David all give research talks at the 2026 VT Geosciences Graduate Student Research Symposium (GSRS). David received the Alex Trebek Award for answering the hardest question 🏆
Feb 17, 2026—New paper by GRG alum, Ryan Riggs, published in Environmental Research Letters titled, "Characterizing operational signatures of reservoirs with the SWOT satellite by comparing natural lake and reservoir dynamics". This study uses SWOT satellite observations to track the amount of water flowing into and out of lakes and reservoirs across North America:
https://doi.org/10.1088/1748-9326/ae436e
Feb 9, 2026—Hana hosts Dr. Konstantin Klemmer for the Virginia Tech Remote Sensing seminar series. Dr. Klemmer is a Principal AI Research Engineer at LGND AI and an expert in remote sensing foundation models. The title of his talk is "Earth Embeddings: Learning Neural Representations of our Planet". Bio: https://konstantinklemmer.github.io
Jan 16, 2026—Virginia Tech News publishes a press release covering Molly's recent article in GSA Today: https://news.vt.edu/articles/2026/01/science-how-water-shapes.html
Jan 12, 2026—Paper published in IEEE Geoscience and Remote Sensing Letters titled "Improving the Spatial Representation of Reservoir Evaporation Using SAR-Based Wind Fields". Led by Katie McQuillan (former Global Rivers Group postdoc, now at pano.ai), this study leverages satellite radar-based wind estimates to map lake evaporation at 25× finer resolution than operational surface analysis products: https://doi.org/10.1109/LGRS.2026.3652374
Dec 19, 2025—Dr. Molly Stroud is formally hooded in conferral of her Doctor of Philosophy degree in the Virginia Tech Graduate School graduation ceremony. Huge congratulations, Molly!
Dec 15–19, 2025—Emily, Yohtaro, Hana, David, and George travel to New Orleans to attend, convene, and present at the AGU2025, the largest earth science conference in the world. GRG AGU scientific abstracts are listed here: https://agu.confex.com/agu/agu25/meetingapp.cgi/Person/28897