Quantifying loop topology in coastal river channel networks

Jose Silvestre, University of Arkansas Fayetteville Arkansas, United States. js522@uark.edu

Aaron Winn, University of Pennsylvania Pennsylvania, United States. winna@sas.upenn.edu

Eleni Katifori, University of Pennsylvania Pennsylvania, United States. katifori@sas.upenn.edu

John Shaw, University of Arkansas Fayetteville Arkansas, United States. shaw84@uark.edu

Coastal deltaic landscapes, home to ~300 million people, are shaped by dynamic river channel networks that distribute water, sediment, and nutrients. The topology of these river channel networks can range from dendritic (e.g., Mississippi River Delta), to looping (e.g., Ganga-Brahmaputra-Meghna Delta). Loops in coastal river channel networks can signal a balance between fluvial and tidal forcings. However, we lack a quantitative framework to describe their shapes and variability. Here, we leverage a simple model adapted from vascular biophysics for river channel network evolution to compare observations of loop geometries from both modelled and field-derived channel networks. A dimensionless parameter, T*, defined as the ratio between tidal and fluvial fluxes, governs whether the emergent network is dendritic or looping. We compared metrics for loop geometry such as shape factor, aspect ratio, and the angular correlation between loops (angle between loops as a function of distance) between model simulations and 18 real-world river delta channel networks that span a range of T* values. Preliminary work shows there is good agreement in the shape of loops between simulated and field-scale systems and that loop shape is relatively invariant to T*. Our results build toward a framework for interpreting morphodynamic signatures in loop geometry, which can prove useful for predicting changes in channel networks under changing climatic and human conditions.

2026 CSDMS meeting-082

Quantifying loop topology in coastal river channel networks