Impact of Wetland Surface Area on Seasonal Daily Extreme Flow Characteristics during the Summer-Fall Season in Southern Quebec (Canada)
Abstract The objective of this paper is to determine the impact of wetlands on the characteristics (magnitude, frequency, duration, timing and variability flow) of daily maximum and minimum extreme flows in summer-fall season (July to November) over the 1945-2019 period in Petite Nation watershed. Three relatively close watersheds [Matawin River (1,390km²), Petite Nation River (1,330km²) and L’Assomption River (1,340km²)], which are differentiated mainly by the types of land use (wetland and agricultural areas), were studied. In the Petite Nation River watershed, which has the largest wetland surface area (15%), the frequency of flood occurrence significantly decreased, resulting in a decrease in the magnitude and duration of seasonally daily maximum flows and their early occurrence during the season. In contrast, the interannual rate change flow in the timing and duration of these flows is greater than that observed in the other two watersheds. The “sponge effect”