CGRG Bibliography of Canadian Geomorphology
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Author : Orwin, J.F.; and Smart, C.C.
Date : 2002.
Title : Short-term spatial and temporal patterns of proglacial suspended sediment transfer, Small River glacier, British Columbia.
Publication : Geological Association of Canada and Mineralogical Association of Canada Joint Annual Meeting, May 27 - 29, 2002. Saskatoon, Saskatchewan.
Issue :
Page(s) :
Abstract
The proglacial zone in alpine glacial basins is a significant source and storage area for sediment exposed by glacial retreat. Patterns of sediment transported in suspension by proglacial streams have been used as a direct measure of glacial denudation rates. However, recent research indicates that short-term storage and release in proglacial channels may control the patterns. These patterns vary spatially and temporally. Accurate characterization of the contribution of proglacial channels therefore requires spatial networks that provide continuous temporal records of suspended sediment. We used continuously recording turbidimeters installed on a network of seven gauging sites within three subcatchments that sampled the entire proglacial area at Small River glacier, British Columbia. Discharge and turbidity were measured at 5 min. intervals over one ablation season. Multivariate statistics were used to extract and characterize differences in suspended sediment transfer patterns. Diurnal patterns dominated suspended sediment transfer (- 80% of days). Variable transfer patterns were associated with ‘high magnitude’ snowmelt and storm events. These events resulted in the transfer of approximately 70% of the total suspended sediment load in some subcatchments. Suspended sediment enrichment of up to - 600% occurred between the glacial front and distal proglacial boundary. Results confirmed that the proglacial area, and in particular, the proglacial channel controlled suspended sediment transfer patterns. However, these patterns varied between subcatchments. This variability was largely due to differences in meteorological forcing of discharge and suspended sediment transfer and did not appear to be sediment supply limited. The proglacial control on suspended sediment transfer has implications for interpretation of suspended sediment yield from glacierized basins. Suspended sediment yield measured at a distance from the glacial front is unlikely to be representative of glacial denudation rates due to increasing proglacial control on transfer patterns. To characterize this control accurately requires multiple gauging sites. Accurate characterization of proglacial control on suspended sediment transfer may therefore aid interpretation of suspended sediment yield patterns from glacierized basins.
Bibliography of Canadian Geomorphology