River hydraulics, sediment transport and training works: their ecological relevance to European rivers
Carling, P. A.; Kohmann, F.; Gölz, E.
Engineering works to canalize major rivers often result in a degradation of ecological habitats and diversity by modifying the river hydraulics and sediment transport. In this paper a broad review is made of hydraulic and sediment transport processes in both the main navigation channel and backwaters of large engineered river channels. Although information is drawn from studies on the rivers Main, Danube, Elbe and Severn, particular emphasis has been given to establishing the typical cross-channel variations in bed-sediments. hydraulics and macroinvertebrate populations associated with trained reaches of the River Rhine. Here major river engineering works have concentrated both bedload transport and frequent bed-disturbance by barge traffic in the navigation channel, with nearbank regions developing distinctive sediment and macroinvertebrate assemblages. New methods of monitoring the spatial and temporal variation in the hydraulic processes of large rivers are referred to and the importance of biofilms for constraining such factors as shear stress on macrobenthos and the scour of bed-sediments is noted as requiring further research.