Response and resiliency of rivers and streams to natural and anthropogenic stressors

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Rivers and streams are very sensitive to changes in discharge conditions resulting from natural disturbances (such as seasonal variation in flow regime) and anthropogenic stressors (such as flow regulation, river engineering and stream modification projects). Complex interactions between stream hydraulics and sediment transport result in morphological adjustments in rivers where the stream bed and banks undergo processes of erosion and deposition. These morphological adjustments can be very substantial, resulting in rivers and streams that migrate across the floodplain and erode considerable amount of land. Such large-scale morphological adjustments can have severe short- and long-term consequences to flood hazard, ecosystem health and the downstream transport of pollutants. It is imperative to be able to predict the nature of the morphologic and hydraulic response of rivers and streams to natural and anthropogenic stressors in order to design engineering solutions and management plans to minimize such adverse impacts. The goal of this research is to investigate the response and resiliency of alluvial rivers and streams to natural disturbances and anthropogenic stressors through a series of laboratory and field-based investigations. The research undertaken within this program will use state-of-the-art infrastructure and equipment to assess the effect of the planform morphology of meandering streams on their stability, characterize the nature of sediment transport in complex riverine environments, and evaluate the effect of river engineering and stream modifications on natural hydraulic and morphologic processes occurring in the stream. This research is important to river engineers and hydrologists who design remediation measures to restore degraded rivers and streams, numerical modellers who require fundamental insight into the morphological and hydraulic response to complex discharge conditions, and watershed managers and land-use planners who seek to balance ecological, social and economic functions of river systems to ensure sustainable management of surface water systems. This research will result in the development of new knowledge of fundamental hydraulic and morphologic processes in alluvial rivers and streams and provide a greater understanding of the specific morphologic and hydraulic factors and drivers responsible for alterations to riverine processes. Results from this research will also assist in developing improved guidelines for river engineering and stream restoration projects in Canada and contribute to regulatory guidelines such as Ontario's Stream Restoration Manual and the Ontario Ministry of the Environment, Conservation and Parks Stormwater Management Planning and Design Manual. The development of a greater understanding of the response and resiliency of rivers and streams to natural and anthropogenic stressors will lead to more sustainable management of the riverine environment.