Generation Mechanisms and Probabilistic Assessment of Peak Spring Streamflow in the Canadian Prairies

Peak spring streamflow is triggered in the Canadian prairies with complex generation mechanisms. The study characterizes the generation mechanisms of peak spring streamflow and models the basin response to changing hydro-climatic basin conditions. Key hydro-climatic basin descriptors were defined and used to set criteria for identifying different flood generation mechanisms, associated with the historical floods at 109 Canadian prairie basins. The temporal and spatial heterogeneity of these mechanisms were investigated, and a t-copula model was used to model the dependence structure between the basin descriptors and peak spring streamflow. The study: (1) suggests seven basin descriptors for characterizing the generation mechanism of peak spring streamflow; (2) discloses four levels of wetness conditions and nine flood generation mechanisms in the Canadian prairies; and (3) highlights the advantages and challenges of probabilistically assessing the basin response (peak spring streamflow) in relevance to historical and hypothetical basin conditions. We deem these results enhance the characterization of flood generation mechanisms in the Canadian prairies and advance the risk estimation of peak spring streamflow.

Automated summary

This study describes and models the flood generation mechanisms in the Canadian prairies, and proposes a model to represent the dependence structure between basin descriptors and peak spring streamflow. The results reveal different flood generation mechanisms and wetness conditions in the Canadian prairies, and highlight the advantages and challenges of probabilistically assessing the basin response to historical and hypothetical conditions.