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Abstract

In recent years several parts of Canada have experienced unprecedented floods which caused significant social, environmental, and economic losses. These flood events are predominantly produced by varying hydro meteorological events, such as excessive precipitation, snowmelt runoff, or ice jams. Researchers around the globe have shown that flood frequency and seasonality analysis are the most powerful tools to minimize the effects of such flood events. These tools analyze the probability and levels of occurrence of peak floods and facilitate the time to take necessary mitigation steps in advance. This paper examines the nature of seasonality and frequency of peak floods in Canadian watersheds using the peak over threshold (POT) approach. 110 watersheds from various Canadian provinces were selected, with data for the last 40-60 years being used for each watershed. The variations in watershed flood responses are described by classifying the watersheds by hydrologic regime (nival, mixed, and pluvial). Our analysis results have shown that while the snow melts significantly influence the flood events in nival catchments that are found in western and northern Canada, there are several factors that influence the flood events in mixed catchments that are found in central and eastern Canada.