Abstract:
River deltas are highly dynamic systems that support both a large human population and diverse ecosystems. These systems are shaped by networks of distributary channels that transport water, sediment, and nutrients, continuously building and modifying the adjacent landscape. Despite extensive research, predicting the evolution of deltaic distributary channel networks (DCNs) remains a significant challenge. In this talk, I will present our latest research on the factors that govern DCN growth. We demonstrate that the complexity of predicting DCN expansion can be substantially reduced by integrating hydrodynamics, sediment transport principles, and the topological and geometric characteristics of DCNs. We introduce a simple hydrodynamic parameter that not only predicts the rate of DCN growth but also determines when growth ceases. Applying this framework to Arctic DCNs suggests that, despite increased future precipitation, these currently stagnant networks are unlikely to reactivate due to the region’s unique hydrological conditions. This approach offers promising avenues for further exploration, particularly in highly anthropogenic deltas undergoing rapid environmental and climatic changes.
Bio:
Dr. Hongbo Ma is currently an Assistant Professor in the Department of Civil and Environmental Engineering at the University of Illinois Urbana-Champaign (UIUC), a position he has held since June 2025. He earned his B.S. and Ph.D. in Hydraulic Engineering from Tsinghua University, China, in 2009 and 2014, respectively. Following postdoctoral appointments at several U.S. universities, including Rice University, the University of Virginia, and the University of California, Irvine, he returned to Tsinghua University, where he served as an Assistant Professor and later as an Associate Professor. Dr. Ma’s research focuses on sediment-laden flows and their geomorphic expressions across diverse environments, with particular contributions to understanding fine-grained sediment transport and the morphology of fine-grained depositional systems. His first- and corresponding-authored research has been published in PNAS, Science Advances, and Nature Communications, among other leading journals, and he has authored more than 40 peer-reviewed papers in mainstream outlets. Dr. Ma received the Leopold Early Career Award and the Rob Sharp Lecture Award from the American Geophysical Union (AGU). He also serves on the AGU Earth and Planetary Surface Processes (EPSP) Honors and Awards Committee and as an Associate Editor for the Journal of Geophysical Research: Earth Surface.