CGRG Bibliography of Canadian Geomorphology
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Author : Dawson, M.
Date : 1988.
Title : Sediment size variation in a braided reach of the Sunwapta River, Alberta, Canada
Publication : Earth Surface Processes and Landforms
Issue : 13(7):
Page(s) : 599-618
Abstract
The downstream diminution of sediment size in a braided reach of the proglacial Sunwapta River, Alberta, Canada, was examined statistically to identify the sources of the observed variation about an expected exponential relationship between clast size and distance. Major deviations from this hypothetical relationship, such as a relative increase in grain-size, may be attributed to the effects of tributary sediment inputs and downstream changes in channel behaviour, whilst local variation is associated with complex patterns of sediment deposition at a bar scale. A comparison of diminution coefficients, calculated for separate lithologies and for subreaches along the river, with those obtained from previous studies, is used as an indicator of river behaviour and sediment transport processes. It is shown that rates of diminution vary within the reach in response to differing rates of aggradation and to the backwater effects caused by tributary alluvial fans. The relatively high values for the calculated diminution coefficients indicate that processes of differential transport are the main cause of the grain size decrease.
Bibliography of Canadian Geomorphology