Year: 2025
Type: article
Abstract: Sand‐bedded rivers self‐organize into bedforms regulating flow resistance and sediment transport. Emerging research focuses on characterizing multiscale bedform configurations, but their stability remains unknown. Here, we analyzed twelve flume experiments of varying sizes to uncover a sharp transition between two independent multiscale bedform configurations. Bedform groups—quasi‐stable collections of bedforms—that have similar heights and celerities as constituent bedforms are found in flows with suspension number (ratio of shear velocity to sediment settling velocity; ) less than 1. In contrast, large dunes with smaller, faster‐moving superimposed bedforms characterize flows with > 1. The transition between these two states abruptly occurs at in low Froude‐number flows, and is further supported by distinct autogenic noise characteristics in bed evolution. Our work provides novel insight into factors controlling multiscale bedform configurations, and highlights the critical influence of suspension number on river morphology.
Source: Geophysical Research Letters
DOI: 10.1029/2025gl118066
Authors: Debsmita Das, Vamsi Ganti, Robert C. Mahon
Institutions: University of California, Santa Barbara, LSU New Orleans
Language: English
Subfield: Ecology
Field: Environmental Science
Domain: Physical Sciences
Open Access status: gold
Estimated APC paid: $3,190
Awards: G4557732362, Collaborative Research: Reconstructing paleo-sediment flux from river deposits: toward quantifying sediment discharge from bedform to basin scale, RII Track-4: Improving Understanding of River Flood Dynamics by Relating Flow and Sediment Movement to Shapes of River Dunes in three dimensions
OpenAlex ID: W4416593140