EAR-Climate: Global Survey of Multiscale River Mobility and its Response to Climate Change and Human Interference

University Of California-Santa Barbara, Santa Barbara CA

Investigators

Abstract

Rivers are inherently mobile. Mobility comes in all shapes and sizes, from the downstream march of the smallest sandbar to the wholesale diversion of river channels after a major flood. It remains unclear how these multiple scales of river mobility are responding to ongoing climate change and human activities (e.g., dams, deforestation), which are drastically disrupting the water and sediment supplied to rivers worldwide. This team of investigators will tackle this knowledge gap by surveying multiscale river mobility in the satellite archive—nearly a half-century of global imagery—using state-of-the-art image processing. The project will provide opportunities for interdisciplinary training to undergraduate students, one graduate student, and one postdoctoral researcher. It will also provide K-12 outreach to underrepresented groups in partnership with existing programs, and deliver a valuable public dataset to inform future studies and management along rivers in our changing world. To survey multiscale river mobility, investigators will leverage two state-of-the-art image-processing techniques. First, the smaller-scale motion of individual banks and bars will be captured using particle image velocimetry. Second, the larger-scale motion of channel diversions, floodplain reworking, and other processes will be captured using reach-scale pixel-based methods. Then, investigators will couple river mobility results with global observations and models of sediment and water supply to test two specific hypotheses: 1) the pace of large-scale river mobility is set by the long-term supply of water and sediment; and 2) the pace of small-scale bank movements has changed in response to recent climate- and human-induced disruption in water and sediment supply, with some degree of natural variability that depends on river type (e.g., meandering, braided). This work will advance our understanding and ability to comparatively analyze river mobility across the globe. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.