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Meander cutoffs nonlocally accelerate upstream and downstream migration and channel widening
Author(s) -
Schwenk Jon,
FoufoulaGeorgiou Efi
Publication year - 2016
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1002/2016gl071670
Subject(s) - meander (mathematics) , cutoff , geology , channel (broadcasting) , downstream (manufacturing) , upstream (networking) , hydrology (agriculture) , geomorphology , physics , geometry , geotechnical engineering , computer science , quantum mechanics , economics , computer network , operations management , mathematics
The hydrologic and sediment dynamics within and near cutoffs have long been studied, establishing them as effective agents of rapid local geomorphic change. However, the morphodynamic impact of individual cutoffs at the reachwide scale remains unknown, mainly due to insufficient observations of channel adjustments over large areal extents and at high temporal frequency. Here we show via annually resolved, Landsat‐derived channel masks of the dynamic meandering Ucayali River in Peru that cutoffs act as perturbations that nonlocally accelerate river migration and drive channel widening both upstream and downstream of the cutoff locations. By tracking planform changes of individual meander bends near cutoffs, we find that the downstream distance of cutoff influence scales linearly with the length of the removed reach. The discovery of nonlocal cutoff influence supports the hypothesis of “avalanche”‐type behavior in meander cutoff dynamics and presents new challenges in modeling and prediction of rivers' self‐adjusting responses to perturbations.