Authors: Trung Tran*, Louisiana State University, Kory M Konsoer, Louisiana State University
Keywords: meandering rivers, neck cutoff, remote sensing
Session Type: Virtual Poster
Start / End Time: 3:05 PM / 5:50 PM
Room: Virtual 52
Presentation File: No File Uploaded
As meandering rivers migrate laterally through their floodplain, the growth of individual bends increases the overall length and sinuosity of the channel. Intermittently, meander bends can be removed from the main course of a river through cutoff processes, thereby shortening the overall length of the river. Meander cutoffs can form via two primary mechanisms, either chute or neck. Chute cutoffs occur during periods of the overbank flood when a new cutoff channel is incised into the floodplain. Neck cutoffs occur when the upstream and downstream limb of meander bends migrate toward one another until the floodplain distance between the two limbs is less than the reach-averaged bankfull width and a cutoff channel forms across the narrowed floodplain. The dynamics of meander cutoff has been of interest to river scientists for many years. However, the spatial distribution of cutoffs around the globe and the relative percentage of chute versus neck cutoffs, and how those relate to geologic and environmental factors have yet to be fully investigated. Using remotely sensed imagery, we present a global database of over 600 cutoffs that have occurred between 1984-2018. The spatial distribution of chute and neck cutoffs are elucidated, and statistical analyses are used to characterize neck cutoffs into four groups based on cutoff centerline curvature. The findings from this study are used to introduce new conceptual models that incorporate the natural planform variability observed around the globe, allowing for improved predictions of meandering river dynamics.