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dc.contributor.authorWilliams, RD
dc.contributor.authorRennie, CD
dc.contributor.authorBrasington, J
dc.contributor.authorHicks, DM
dc.contributor.authorVericat, D
dc.descriptionAccepted for publication in Journal of Geophysical Research. Copyright 2015 American Geophysical Union. Further reproduction or electronic distribution is not permitted.en_US
dc.description.abstract©2015. American Geophysical Union. All Rights Reserved.This paper provides novel observations linking the connections between spatially distributed bed load transport pathways, hydraulic patterns, and morphological change in a shallow, gravel bed braided river. These observations shed light on the mechanics of braiding processes and illustrate the potential to quantify coupled material fluxes using remotely sensed methods. The paper focuses upon a 300 m long segment of the Rees River, New Zealand, and utilizes spatially dense observations from a mobile acoustic Doppler current profiler (aDcp) to map depth, velocity, and channel topography through a sequence of high-flow events. Apparent bed load velocity is estimated from the bias in aDcp bottom tracking and mapped to indicate bed load transport pathways. Terrestrial laser scanning (TLS) of exposed bar surfaces is fused with the aDcp surveys to generate spatially continuous digital elevation models, which quantify morphological change through the sequence of events. Results map spatially distributed bed load pathways that were likely to link zones of erosion and deposition. The coherence between the channel thalweg, zone of maximum hydraulic forcing, and maximum apparent bed load pathways varied. This suggests that, in places, local sediment supply sources exerted a strong control on the distribution of bed load, distinct from hydraulic forcing. The principal braiding mechanisms observed were channel choking, leading to subsequent bifurcation. Results show the connection between sediment sources, pathways, and sinks and their influence on channel morphology and flow path directions. The methodology of coupling spatially dense aDcp surveys with TLS has considerable potential to understand connections between processes and morphological change in dynamic fluvial settings.
dc.description.sponsorshipThe field campaign was funded by NERC grant NE/G005427/1 and NERC Geophysical Equipment Facility Loan892, as well as NSERC and CFI (Canada) grants to Colin Rennie. Damia Vericat has benefited from a Ramon y Cajal Fellowship (RYC-2010-06264) during the preparation of this manuscript. Richard Williams was funded by NERC grant NE/G005427/1 during fieldwork and an Aberystwyth University Postgraduate Studentship during the preparation of this manuscript. Murray Hicks was supported by NIWA ’s core-funded Sustainable Water Allocation Programme.en_US
dc.format.extent604 - 622
dc.relation.ispartofJournal of Geophysical Research F: Earth Surface
dc.rightsAll rights reserved
dc.titleLinking the spatial distribution of bed load transport to morphological change during high-flow events in a shallow braided river
dc.typeJournal Article
dc.rights.holder©2015. American Geophysical Union
dc.relation.isPartOfJournal of Geophysical Research F: Earth Surface
pubs.organisational-group/Queen Mary University of London
pubs.organisational-group/Queen Mary University of London/Faculty of Humanities, Social Sciences & Law
pubs.organisational-group/Queen Mary University of London/Faculty of Humanities, Social Sciences & Law/Geography - Staff

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