Author(s): C. D. Rennie; M. R. Ahsan; M. St. Laurent
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Keywords: Sediment transport; Total sediment load; River regulations; Semi-alluvial; Measurement
Abstract: The Lower Nelson River in northern Manitoba, Canada is regulated by Manitoba Hydro with three hydroelectric dams as well as diversion from the Churchill River. The river is partially controlled by bedrock and is incising into glacio-marine tills. The surrounding landscape is boreal forest with discontinuous permafrost. In preparation for the proposed Keeyask Generating Station at Gull Rapids, sediment transport throughout both a riverine reach and the lacustrine/reservoir reach upstream of the current dams was characterized by means of three years of physical sampling of suspended load and bedload. Both suspended load and bedload were low due to the influence of upstream lakes. Suspended sediment was generally wash load, and rating curves displayed distinct hysteresis, suggesting seasonal depletion of sediment supply. Up to 2/3 of the sediment transported in the upstream riverine reach was deposited in the existing reservoir downstream of Gull Rapids.
Year: 2011