Fluvial geomorphology and the winter habitat of stream salmonids

点击翻译按钮获取中文摘要

The long-term objective of the research program is to improve our understanding of the fluvial forms and processes controlling the winter habitat of stream salmonid. Gravel-bed rivers can often be segmented into a number of discrete sedimentary links, each characterized by a node of coarse sediment recruitment followed by a gradual downstream fining of substrate and an associated reduction of channel slope. Because the downstream changes in substrate and slope along sedimentary links are associated with changes in channel morphology and hydraulics, they create a longitudinal sequence of aquatic habitat types moving from steep, fast flowing and turbulent boulder bed channels at the head of links to meandering, slow-flowing, low-gradient sand channels at the downstream end. Over the next five years, I will investigate more closely the important role of sedimentary links in controlling the spatial and temporal distribution of juvenile Atlantic salmon winter habitat in gravel-bed rivers. The specific objectives of the proposed research are: (1) To test the hypothesis that sedimentary links exerts a strong control on the spatial and temporal pattern of juvenile Atlantic salmon winter habitat, (2) To test the hypothesis that sedimentary links exerts a strong control on the large-scale distribution of river ice types, (3) To investigate the response of salmon parr to the changing habitat conditions created by the formation of river ice, and (4) To asses the effect of anchor ice on the interstitial flow velocities of salmonid spawning substrates.