CGRG Bibliography of Canadian Geomorphology
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Author : Desloges, J.R.; Croil, J.; Stewart, A.; Dirszowsky, R.; and Hodder, K.
Date : 2003.
Title : Floodplain accretion processes as indicators of Holocene sediment yield.
Publication : 99th Annual Meeting of the Association of American Geographers. New Orleans, Louisiana, March 5-8, 2003.
Issue :
Page(s) :
Abstract
Floodplains accumulate as a result of both continuous and episodic exchanges of sediment between the active channel(s) and the surrounding alluvial valley flat. Lateral and vertical accreted sediments are potential archives of the magnitude and rate of these exchanges and they can be correlated with overall sediment transport capacity and sediment yield variations in the contributing watershed. Three factors limit the strength of this correlation for selected Canadian rivers: 1) an incomplete understanding of sediment sources and processes of sediment conveyance from the upper watershed, 2) the potential for secondary re-working of the alluvial sediment and thus establishing a definitive chronology of deposition and; 3) accounting for the affects of vertical stability (particularly degradation) and non-alluvial boundary conditions.. Each of these factors is considered in examples drawn from four different rivers - two in southern Ontario and two in British Columbia. Common to all these rivers are the greater importance of vertical accretion processes and the larger volume of older floodplain than what would be predicted from morphologic evidence alone. Major re-working of sediments by large floods appears to be minimal and the chronology of lateral migration or channel splitting can be reconstructed with some confidence. Floodplain "recruitment" or turnover rates are presented for each case and preliminary results indicate that there is a strong linkage between these rates and available stream power. We conclude that precise determination of transport and yield rates from these recruitment curves requires finer temporal resolution of floodplain accumulation.
Bibliography of Canadian Geomorphology