Global river database documents 40 years of change

Date:
November 9, 2021
Source:
University of Texas at Austin
Summary:
A new database compiling movement of the largest rivers in the
world over time could become a crucial tool for urban planners to
better understand the deltas that are home to these rivers and a
large portion of Earth's population.



FULL STORY ==========================================================================
A first-ever database compiling movement of the largest rivers in the
world over time could become a crucial tool for urban planners to better understand the deltas that are home to these rivers and a large portion
of Earth's population.


==========================================================================
The database, created by researchers at The University of Texas at
Austin, uses publicly available remote sensing data to show how the
river centerlines of the world's 48 most threatened deltas have moved
during the past 40 years. The data can be used to predict how rivers
will continue to move over time and help governments manage population
density and future development.

"When we think about river management strategies, we have very
little to no information about how rivers are moving over time," said
Paola Passalacqua, an associate professor in the Cockrell School of Engineering's Department of Civil, Architectural and Environmental
Engineering who leads the ongoing river analysis research.

The research was published today in Proceedings of the National Academy
of Sciences.

The database includes three U.S. rivers, the Mississippi, the Colorado
and the Rio Grande. Although some areas of these deltas are experiencing migration, overall, they are mostly stable, the data show. Aggressive containment strategies to keep those rivers in their place, especially
near population centers, play a role in that, Passalacqua said.

Average migration rates for each river delta help identify which areas
are stable and which are experiencing major river shifts. The researchers
also published more extensive data online that includes information
about how different segments of rivers have moved over time. It could
help planners see what's going in rural areas vs. urban areas when making decisions about how to manage the rivers and what to do with development.

The researchers leaned on techniques from a variety of disciplines to
compile the data and published their methods online. Machine learning
and image processing software helped them examine decades' worth of
images. The researchers worked with Alan Bovik of the Department of
Electrical and Computer Engineering and doctoral student Leo Isikdogan
to develop that technology. They also borrowed from fluid mechanics,
using tools designed to monitor water particles in turbulence experiments
to instead track changes to river locations over the years.

"We got the idea to use tools from fluid mechanics while attending a
weekly department seminar where other researchers at the university
share their work," said Tess Jarriel, a graduate research assistant in Passalacqua's lab and lead author of the paper. "It just goes to show
how important it is to collaborate across disciplines." Rivers that have
high sediment flux and flood frequency move more as it is in their nature
and part of an important tradeoff that underpins Passalacqua's research.

By knowing more about these river deltas where millions of people live, planners can have a better idea of how best to balance these tradeoffs.

Passalacqua, as well as researchers in her lab, have recently published research about these tradeoffs between the need for river freedom and humanity's desire for stability.

Passalacqua has been working on this topic for more than eight years. The
team and collaborators are in the process of publishing another paper
as part of this work that expands beyond the centerlines of rivers and
will also look at riverbanks. That additional information will give an
even clearer picture about river movement over time, with more nuance,
because sides of the river can move in different directions and at
different speeds.

The research was funded through Passalacqua's National Science Foundation CAREER award; grants from the NSF's Ocean Sciences and Earth Sciences divisions; and Planet Texas 2050, a UT Austin initiative to support
research to make communities more resilient. Co-authors on the paper
are Jarriel and postdoctoral researcher John Swartz.

========================================================================== Story Source: Materials provided by University_of_Texas_at_Austin. Note: Content may be edited for style and length.


========================================================================== Journal Reference:
1. Teresa Jarriel, John Swartz, Paola Passalacqua. Global rates
and patterns
of channel migration in river deltas. Proceedings of the
National Academy of Sciences, 2021; 118 (46): e2103178118 DOI:
10.1073/pnas.2103178118 ==========================================================================

Link to news story: https://www.sciencedaily.com/releases/2021/11/211109135453.htm

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