HR: 08:15h
AN: H51H-02    [Abstracts]
TI: Effect of Hydrograph Characteristics on Vertical Grain Sorting in Gravel Bed Rivers
AU: * Hassan, M A
EM: mhassan@geog.ubc.ca
AF: University of British Columbia, Department of Geography, 1984 West mall, Vancouver, B.C V6T 1Z2 Canada
AU: Parker, G
EM: parkerg@uiuc.edu
AF: University of Illinois Urbana-Champaign, Department of Civil and Environmental Engineering, 205 N. Mathews Avenue, Urbana, IL 61801 United States
AU: Egozi, R
EM: regozi@uwo.ca
AF: University of Western Ontario, Department of Geography, London, ON N6A 5C2 Canada
AB: This study focuses on the formation of armour layers over a range of hydrologic conditions that includes two limiting cases; a relatively flat hydrograph that represents conditions produced by continuous snowmelt and a sharply peaked hydrograph that represents conditions associated with flash floods. To achieve our objective we analyzed field evidence, conducted flume experiments and performed numerical simulations. Sediment supply appears to be a first-order control on bed surface armouring, while the shape of the hydrograph plays a secondary role. All constant hydrograph experiments developed a well-armored structured surface while short asymmetrical hydrographs did not show substantial vertical sorting. All symmetrical hydrographs show some degree of sorting, and the sorting tended to become more pronounced with longer duration. Using the numerical framework of Parker, modified Powell, et al. and Wilcock and Crowe, we were able to achieve similar results.
DE: 1815 Erosion
DE: 1824 Geomorphology: general (1625)
DE: 4558 Sediment transport (1862)
SC: Hydrology [H]
MN: Fall Meeting 2005