Energy - Environment - Food and Water

Let’s Get Connected: Understanding Braided River Morphodynamics

There are striking similarities between the structure of natural river networks and others found in systems as diverse as brains, roads and the communication technologies. Using a series of examples, the authors illustrate how a suite of graph theory-based metrics derived from diverse disciplines can be used to provide new insights into the structure and kinematics of braided river networks.

Braided rivers are one of the most dynamic natural landforms that shape the surface of our planet. They comprise networks of multiple active channels that split apart and then come together, separating and enclosing areas of exposed sediment and vegetated islands.  These networks are continuously changing in response to the erosion, transport and deposition of sediment.  The complexity and dynamism of braided river form gives rise to distinctive and rare ecological communities, but also creates challenges for the design and management of floodplain infrastructure and the effective description, quantification and classification of braided rivers.

The recent revolution in availability of satellite-based Earth observation data provides important opportunities for new insights into braided river behaviour at multiple scales and through time, overcoming some of the shortcomings of traditional approaches. But in order to fully exploit these new resources we need new tools to retrieve and analyze braided river networks.

Research published in WIREs Water presents a new approach and toolbox for understanding braided river form and dynamics. The study, led by Queen Mary University of London in collaboration with the University of Waikato and University of Trento, examines the potential to leverage developments in graph theory (the mathematics of networks) to establish a new perspective on the mathematical structure of braided river networks.

There are striking similarities between the structure of these natural river networks and others found in systems as diverse as brains, roads and the communication technologies. Using a series of examples, the authors illustrate how a suite of graph theory-based metrics derived from diverse disciplines can be used to provide new insights into the structure and kinematics of braided river networks. It is also argued that this approach can help to close the loop in the use of numerical models, providing new data to test model performance and expose the exploratory power of these tools.

This is a new and exciting area of research that crosses disciplinary boundaries, from the mathematical and physical sciences through to ecology and evolution. Indeed, it was similarities between filaments in star formation and braided rivers that originally stimulated this research. Uncovering further striking structural resemblances between brains and braided rivers then spurred it on, and it is hoped that future synergies between the brains that research all different kinds of networks can help promote new insights into the behavior of these emergent phenomena.

 

Kindly contributed by Gabriel M C Streich, Alexander J. Henshaw, James Brasington, Walter Bertoldi, Gemma L. Harvey.

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