Credit: University of Texas at Austin
The first database to track the movements of the largest rivers around the globe over time could be a key tool for urban planners in order to better understand the deltas where these rivers are found and the large proportion of Earth's inhabitants.
Researchers at The University of Texas at Austin created the database using publicly available remote sensing data. It shows how the river centers of the 48 most endangered deltas around the world have changed over the past 40 years. This data can be used by governments to manage future development and population density, and to predict how rivers will move in the future.
Paola Passalacqua, associate professor at the Cockrell School of Engineering's Department of Civil, Architectural and Environmental Engineering, said that "when we think about river management strategies, there is very little or no information about how rivers move over time." She leads ongoing river analysis research.
Today, the research was published in Proceedings of the National Academy of Sciences.
The database contains three U.S rivers: the Mississippi, Colorado, and Rio Grande. The data shows that although some areas of the deltas experience migration, overall they are stable. Passalacqua stated that aggressive containment strategies are used to keep these rivers in place, particularly near major cities.
The average migration rate for each river delta helps identify areas that are stable and those that are experiencing major river shifts. Researchers also published additional data online, which includes information on how rivers have changed over time. This data could be used to help planners determine how to manage rivers and how to develop them.
Researchers used techniques from many disciplines to compile data. They then published their methods online. They were able to examine images spanning decades using machine learning and image processing software. To develop this technology, the researchers collaborated with Alan Bovik of Electrical and Computer Engineering and Leo Isikdogan, a doctoral student. Fluid mechanics was also used to track changes in river location over time.
Tess Jarriel is a graduate assistant in Passalacqua's laboratory and the lead author of this paper. "We got the idea for fluid mechanics tools while attending a weekly university department seminar where other researchers share their work," she said. It just shows how important it is for researchers to work together across disciplines.
Rivers with high flood frequency and sediment flux move more than they are in nature. This is part of an important tradeoff which underpins Passalacqua research.
Planners will be able to better understand the river deltas that are home to millions of people and can make informed decisions about how to balance these tradeoffs. Passalacqua and her colleagues published recent research on the tradeoffs between river freedom and stability.
Passalacqua has been researching this topic for over eight years. As part of their work, Passalacqua and his collaborators are currently publishing a second paper that will examine riverbanks and extend beyond the rivers' centerlines. This additional information will provide a more detailed picture of river movement over time with more nuance because the sides of rivers can move in different directions at different speeds.
Continue reading The delicate balance between society and river delta protection
More information: Teresa Jarriel and colleagues, Global rates of channel migration in river valleys. Proceedings of the National Academy of Sciences (2021). Information for Journal: Proceedings of the National Academy of Sciences Teresa Jarriel and colleagues, Global rates of channel migration in river Deltas. (2021). DOI: 10.1073/pnas.2103178118
