CGRG Bibliography of Canadian Geomorphology
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Author : Croil, J.; and Desloges, J.R.
Date : 2001.
Title : Controls on lateral channel instability of the Lower Grand River, Ontario.
Publication : The Canadian Association of Geographers/l'association Canadienne des Géographes. 2001 Annual Meeting. 50th Anniversary of the CAG Jointly Organised by McGill University, Concordia University and Université de Montréal Tuesday May 29 – Sunday June 3, 2001
Issue :
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Abstract
The purpose of this study was to determine the causes, control and chronology of lateral channel instability of the lower Grand River. This low energy river is primarily a very stable, single-thread meandering system comprised of cohesive banks of silt. However, selected reaches are subject to lateral instability and exhibit up to five channels that divide around vegetated islands most of which are of similar height and topography to the adjacent floodplain. Sedimentary units in laterally unstable reaches are coarser, thinner, more highly structured and lack the stable surfaces (paleosols) observed in floodplain sediments from stable single-thread reaches. However, vertical accretion appears to be the dominant mode of sediment accumulation in both reach types. Controls on lateral stability appear to be related to locally increased channel gradients, and variation in confining channel boundary materials such as glacial deposits and bedrock. 14 C dating indicates that laterally unstable sections persist in specific locations and are at least 3500 years younger than single-thread sections. Floodplain architecture and 14C dating also points towards more widespread instability in the river prior to about 500 AD.
Bibliography of Canadian Geomorphology