The role of sediment supply in the adjustment of channel sinuosity across the Amazon Basin

Author:

Ahmed Joshua12,Constantine José Antonio3,Dunne Thomas4

Affiliation:

1. Energy and Environment Institute, University of Hull, Hull HU6 7RX, UK

2. School of Earth and Ocean Sciences, Cardiff University, Cardiff CF10 3AT, UK

3. Department of Geosciences, Williams College, Williamstown, Massachusetts 01267, USA

4. Bren School of Environmental Science and Management, University of California, Santa Barbara, California 93106, USA

Abstract

Abstract Sediment supplies are a fundamental component of alluvial river systems, but the importance of sustained supplies of externally derived sediments for the evolution of meandering planforms remains unclear. Here we demonstrate the importance of sediment supply in enhancing the growth of point bars that influence the rate of sinuosity increase through flow deflections in meander bends. We use an archive of Landsat images of 16 meandering reaches from across the Amazon Basin to show that rivers transporting larger sediment loads increase their sinuosity more rapidly than those carrying smaller loads. Sediment-rich rivers are dominated by downstream-rotating meanders that increase their sinuosity more rapidly than both extensional and upstream-rotating meanders. Downstream-rotating meanders appear to establish larger point bars that expand throughout the meander, in contrast to extensional meanders, which have smaller bars, and upstream rotating meanders, which are characterized by deposition over the bar head. These observations demonstrate that the size and position of point bars within meander bends influences flow routing and thus controls the dominant direction of meander growth. Rivers with low sediment supplies build smaller point bars, which reduces their capacity to increase meander curvature and the resulting sinuosity.

Publisher

Geological Society of America

Subject

Geology

Reference34 articles.

1. Experiments in a high-amplitude Kinoshita meandering channel: 1. Implications of bend orientation on mean and turbulent flow structure;Abad;Water Resources Research,2009

2. Experiments in a high-amplitude Kinoshita meandering channel: 2. Implications of bend orientation on bed morphodynamics;Abad;Water Resources Research,2009

3. Experimental evidence for the conditions necessary to sustain meandering in coarse-bedded rivers;Braudrick;Proceedings of the National Academy of Sciences of the United States of America,2009

4. Fluvial bevelling of topography controlled by lateral channel mobility and uplift rate;Bufe;Nature Geoscience,2016

5. Meander cutoff and the controls on the production of oxbow lakes;Constantine;Geology,2008

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