Turbulent flow structure and flow-biota interactions in open channels

世界各地的河流一直是人类活动的中心。在加拿大，河流是饮用水、食物、交通和能源等便利设施的重要来源。河流还支持着丰富而动态的生态系统，拥有多样化的动植物。虽然河流已经被研究了几十年，但由于其内在的复杂性，对其物理和生物过程的理解仍然有限。鉴于城市化、粗放型农业和气候变化带来的日益增长的压力，我们需要对河流过程和生态-水力相互作用有一个良好的了解，以保持河流的健康。

Rivers around the world have always been at the center of human activity. In Canada, rivers are an essential source of amenities such as drinking water, food, transportation, and energy. Rivers also support rich and dynamic ecosystems, with a diverse flora and fauna. Although rivers have been studied for decades, the understanding of their physical and biological processes is still limited due to their intrinsic complexity. Given the growing pressure from urbanization, extensive agriculture, and climate change, a sound understanding of river processes and ecology-hydraulic interactions is needed to preserve the health of our rivers. In this context, my research aims to investigate physical flow processes occurring in rivers and the relationships between flow structure and aquatic biota (i.e., fish, plants). My research program, in the short-term (next 5 years), is divided along 3 axes. Axis 1 will establish fundamental links between bed roughness and flow structure in open channels. This research will specifically investigate the role of turbulence-induced secondary currents in determining bed shear stress and flow resistance. Axis 2 will investigate the relationships between sediment/solute transport in open channels and vegetated canopies. This will lead to a better understanding of riverbed and bank erosional/depositional processes and pollutant residence times. Axis 3 will investigate fish hydraulic habitat preference and the dynamics of fish swimming behind submerged obstacles (e.g., boulders). A major outcome of this research will be to develop guidelines for the conservation and/or restoration of the preferred fine-scale hydraulic habitat of the target species (e.g., Atlantic salmon). The results from my research will allow engineers and watershed/fisheries managers (in Canada and abroad) to make informed decisions regarding channel conveyance, ecological health, and habitat restoration in rivers.