HR: 1340h
AN: H53C-1272    [Abstracts]
TI: Braided Channel Pattern Morphodynamics: The Physical Controls on Braiding Intensity in Gravel Bed Rivers
AU: * Egozi, R
EM: regozi@uwo.ca
AF: Department of Geography University of Western Ontario, The University of Western Ontario , London, ON N6A 5C2 Canada
AU: Ashmore, P
EM: pashmore@uwo.ca
AF: Department of Geography University of Western Ontario, The University of Western Ontario , London, ON N6A 5C2 Canada
AB: Braiding occurs in alluvial non cohesive river beds where stream power is high relative to sediment size. Previous research has clarified the local mechanisms (e.g. deposition of bars) causing braiding and the overall landscape conditions associated with braided rivers. Surprisingly there is not yet a complete explanation for one of the most important, yet basic characteristic of braided channel pattern - the degree of braiding and its variation spatially and temporally. The goal of this research is to understand the physical controls on braiding intensity (BI) during changes in stage in a particular river and to explain differences in BI at channel-forming conditions in different rivers. Analysis of variation in BI at varying stage is based on field results from Sunwapta River, Alberta, Canada, where changes in bed elevation, flow rate and river morphology were monitored for 12 consecutive days during a glacial runoff season. Daily discharge cycles were also reproduced in physical model experiments in a tilting flume, 18 m long, 3 m wide and 0.2 m deep in which the extent of braiding activity (sediment movement) can be directly observed and compared with field results.
DE: 1800 HYDROLOGY
DE: 1815 Erosion and sedimentation
DE: 1824 Geomorphology (1625)
SC: Hydrology [H]
MN: 2004 AGU Fall Meeting