Coherent flow structures and suspension events over low-angle dunes: Fraser River, Canada

Resource type
Thesis type
(Thesis) M.Sc.
Date created
2012-08-22
Authors/Contributors
Abstract
It is increasingly obvious that dunes with low-angle lee-sides (< 30°) are the most common bedform morphology in large sand-bedded alluvial channels. Flume studies have revealed much about flow and sediment dynamics over high-angle (~30°) dunes, however little is known about low-angle dunes. This study examines flow and suspension events over low-angle dunes in unsteady flow of the Fraser Estuary, Canada. Dune field bathymetry was mapped using a multibeam echo sounder while an acoustic Doppler current profiler simultaneously provided flow and suspended sediment measurements over a range of flows through tidal cycles. Mean flow and sediment transport varied through the tidal cycles. River flow dominated at low tide and large-scale suspended sediment events emerged as important sediment transport agents. I estimate that 69% of the total sediment is carried by 50% of the flow during low tide suspension events dominate the flow field.
Document
Identifier
etd7416
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The author granted permission for the file to be printed and for the text to be copied and pasted.
Scholarly level
Supervisor or Senior Supervisor
Thesis advisor: Venditti, Jeremy
Member of collection
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etd7416_RBradley.pdf 1.87 MB