HR: 0800h
AN: H51A-0169    [Abstracts]
TI: Flow Structure and Secondary Flows in Fine-grained Bifurcate Channels
AU: * Best, J L
EM: jimbest@uiuc.edu
AF: University of Illinois at Urbana-Champaign, Departments of Geology and Geography and Ven Te Chow Hydrosystems Laboratory, 1301 W. Green St., Urbana, IL 61821, United States
AU: Parsons, D R
AF: University of Leeds, Institute of Geological Sciences, School of Earth and Environment, Woodhouse Lane, Leeds, LS29JT, United Kingdom
AU: Bridge, J S
AF: University of Binghamton, Department of Geological Sciences and Environmental Studies, PO Box 6000, Binghamton, NY 13902-6000, United States
AU: Edmonds, D A
AF: The Pennsylvania State University, Department of Geosciences, 513A Deike Building, University Park, State College, PA 16802, United States
AU: Janesko, D
AF: University of Binghamton, Department of Geological Sciences and Environmental Studies, PO Box 6000, Binghamton, NY 13902-6000, United States
AU: Klein, F E
AF: The Pennsylvania State University, Department of Geosciences, 513A Deike Building, University Park, State College, PA 16802, United States
AU: Slingerland, R L
AF: The Pennsylvania State University, Department of Geosciences, 513A Deike Building, University Park, State College, PA 16802, United States
AU: Smith, N D
AF: University of Nebraska, Department of Geosciences, 214 Bessey Hall, PO Box 880340, Lincoln, NE 68588-0340, United States
AB: Bifurcations form vital nodes within many fluvio\-deltaic channels and their stability is critical in determining long- term channel behavior. Although there are an increasing number of laboratory and numerical models detailing flow and morphology within such bifurcations, relatively few field studies exist on the nature of flow within such sites by which to test and validate these models. In particular, the presence and nature of any secondary flow cells is seen as central in controlling fluid and sediment partitioning within the bifurcation, and contributing to long term stability or instability. Here we present results of a field study in the Cumberland Marshes, Saskatchewan, Canada, which sought to document the mean flow fields and patterns of secondary flow at two asymmetric bifurcations within the Mossy River delta. The study used a Teledyne RDI 1200 kHz acoustic Doppler profiler to record three\-dimensional flow velocities along a series of flow\-transverse cross\-sections within these bifurcations. These surveys document the partitioning of main downstream flow through the bifurcation and reveal that bed topographic forcing and secondary flows can be important processes as the flows divide at the bifurcation. These results will be discussed in relation to the functioning of bifurcations and their sediment transport pathways.
DE: 1820 Floodplain dynamics
DE: 1825 Geomorphology: fluvial (1625)
DE: 1862 Sediment transport (4558)
SC: Hydrology [H]
MN: 2007 Fall Meeting