Grant: Discovery Grants Program - Individual

This research program combines theoretical, experimental and numerical research of mechanisms of flow and sediment transport in rivers with the development of physically-based, high-accuracy models and tools for the simulation and prediction of river response to a variety of stressors resulting in altered flow and sediment regimes. Such stressors include climate and land-use changes, as well as interventions related to water exploitation. Over the next five years, we will focus on aspects of the dynamics and prediction of natural and anthropogenic river morphological adjustments of equilibrium occurring at large spatial and temporal scales (multi-year, decadal, and higher). The focus will be on: 1- hydro-morphodynamics of meandering streams; and 2- formation of large-scale bed forms, and more specifically alternate bars, in ice-covered streams.        The primary and secondary motions in meandering streams will be extensively investigated by conducting series of measurements in two large-scale meandering channels formed by a sequence of loops and representing intermediate and high values of sinuosity. A combination of high-resolution cameras and 3-D Acoustic Doppler Velocimeters will be used to resolve the flow fields. The new data and insights will serve as support for a parallel theoretical and numerical study on energy loss and fluxes in meandering streams, that will be founded on the full form of the equations of motion and the open-source code OpenFoam. The study will lead to: 1- novel parametrizations of the secondary motion; 2- a considerable advancement of the state-of-the-art of 2D hydrodynamic modelling, which is critically significant for the development of accurate and reliable models for the prediction and simulation of long-term river morphological changes; and 3- a response to the classical and yet unresolved matter of how to formulate resistance to flow induced by the meandering of the stream, and thereby address an important gap in the literature.        Additionally an extensive series of experiments devoted to ice-covered streams will be conducted in a 21m-long straight channel with an adjustable width from 1 to 2 m. In these experiments, the formation of alternate bars in streams with simulated ice-covers will be monitored and events of generation, growth and decay of large-scale turbulent coherent structures will be recorded. Being the first study of this type, it is expected to yield a first understanding of the formation of alternate bars and of the dynamics and scales of large-scale turbulence in ice-covered streams.        This research program will result in the training of 4 PhD, 3 MSc and 3 BSc students, who will acquire highly desired, advanced skills in hydraulic physical and numerical modeling, a deep appreciation of the societal, economic and environmental consequences of river response, and the ability to mitigate these through a strongly science-based approach to river engineering and management.