Subventions et des contributions :

Subvention ou bourse octroyée s'appliquant à plus d'un exercice financier. (2017-2018 à 2022-2023)

Global warming is predicted to amplify the hydrological cycle in the form of increased cloudiness, latent heat fluxes, intense precipitation events, and flooding. The forecasts of hydrological extremes are now being corroborated by empirical evidence. However, there are still considerable gaps in our understanding of the complex interplay among hydrological factors, morphological features, land uses, and spatial patterns of the urban environment and agricultural activities that will determine flow regimes, nutrient and contaminant attenuation rates in a watershed context. The proposed research program will offer mechanistic insights into the impact of hydrological extremes on integrated watershed-receiving waterbody systems. The main focus of the proposed research will be on Southern Ontario, but the hypotheses tested and conclusions drawn can be transferred and will stimulate research in other regions in Canada or the rest of the world. The main objectives of this research program are the (i) characterization of extreme weather conditions based on historical records of key meteorological variables, (ii) the improvement of our understanding of how extreme events impact flow regimes and nutrient cycling within a watershed context, and (iii) the examination of the implications of the increased frequency of extreme weather events for the resilience of the receiving waterbodies. Three major watershed-receiving waterbody systems will be the focus of the proposed research, the Hamilton Harbour, the Bay of Quinte, and Lake Simcoe. These systems were selected due to the multitude of anthropogenic stressors (urbanization, agriculture) in their watersheds. The anticipated insights into the ability of hydrological extremes to modulate the response of integrated watershed-receiving waterbody systems will offer fundamental knowledge on a "hot theme" in the field of biogeosciences. This research also addresses the urgent need for advanced modelling tools that can support environmental management and make decisions that usually have considerable socioeconomic implications. Our improved understanding of the role of hydrological extremes will be capitalized by the development of novel Bayesian networks of models that offer critical planning information about the optimal mitigation strategies for alleviating the impact of climate change. The application of Bayesian inference is uniquely suitable for the proposed probabilistic characterization of the impact of hydrological extremes due to its ability to rigorously assess the uncertainty associated with models, calibration data, and natural variability. This internationally-leading research will have an enormous impact on the scientific community and will strengthen Canada's ability in the area of watershed and freshwater ecosystem management.