Chatanantavet, Phairot and Lamb, Michael P. (2014) Sediment transport and topographic evolution of a coupled river and river plume system: An experimental and numerical study. Journal of Geophysical Research. Earth Surface, 119 (6). pp. 1263-1282. ISSN 2169-9003. http://resolver.caltech.edu/CaltechAUTHORS:20140918-075846085
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Sediment transfer from rivers to the ocean is the fundamental driver of continental sedimentation with implications for carbon burial, land use dynamics, and unraveling global climate change and Earth history from sedimentary strata. Coastal rivers are dynamically coupled to their offshore plumes at the river mouth creating regions of nonuniform flow that can dictate patterns of erosion and deposition both onshore and offshore. However, there are limited experimental and modeling studies on sediment transport and morphodynamics of coupled river and river plume systems and their response to multiple flood events. To address this knowledge gap, we developed a quasi-2-D, morphodynamic numerical model and conducted exploratory flume experiments in a 7.5 m long flume where a 10 cm wide river channel was connected to a 76 cm wide “ocean basin.” Both the numerical model and the flume results demonstrate that (1) during low-discharge flows, backwater hydrodynamics cause spatial-flow deceleration and deposition in the river channel and the offshore plume area, and (2) during high flows the water surface is drawn down to sea level, resulting in spatial-flow acceleration and bed scour. During high-discharge flows, we also found that the offshore river plume self-channelized owing to both levee formation and bed scour. Our study suggests that coastal rivers may be in a perpetual state of morphodynamic adjustment and highlights the need to link rivers and river plumes under a suite of flow discharges to accurately predict fluvio-deltaic morphodynamics and connectivity between fluvial sediment sources and marine sinks.
|Additional Information:||© 2014 American Geophysical Union. Received 27 MAR 2013; Accepted 28 APR 2014; Accepted article online 4 MAY 2014; Published online 11 JUN 2014. We thank Brian Fuller and Aaron Tran for assisting with parts of the flume experiments. Our analysis benefited from informal discussions with Joel Rowland. This work was funded by the U.S. National Science Foundation grant OCE-1233685 and the American Chemical Society Petroleum Research Fund to MPL. We thank Editor A. Densmore, Associate Editor W. Kim, J. Nittrouer, F. Falcini, and J. Martin for constructive comments on a previous draft. Data sets used to produce the results of this paper have been curated, and readers are encouraged to contact the first author (P.C.) if interested in the data, or visit https://sites.google.com/site/sedimentexperimentalists/ home (then click “Materials” and “Interactive data folder”), with no restrictions on access.|
|Official Citation:||Chatanantavet, P., and M. P. Lamb (2014), Sediment transport and topographic evolution of a coupled river and river plume system: An experimental and numerical study, J. Geophys. Res. Earth Surf., 119, 1263–1282, doi:10.1002/2013JF002810|
|Usage Policy:||No commercial reproduction, distribution, display or performance rights in this work are provided.|
|Deposited By:||Tony Diaz|
|Deposited On:||18 Sep 2014 22:51|
|Last Modified:||23 Nov 2016 00:50|
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