Potential Impacts of Projected Climate Change on Flooding in the Riviere Des Prairies Basin, Quebec, Canada: One-Dimensional and Two-Dimensional Simulation-Based Approach

摘要

Projection of floodplain extents is extremely important in identifying solutions that will establish the controls of land use in flood-loss reduction studies. The Riviere des Prairies, located in the province of Quebec, Canada, has many rapids that make the river basin highly vulnerable to potential flood loss. The aim of this study was to evaluate the hydrological and environmental impacts that climate change may have on the Riviere des Prairies basin. The design rainfalls considered are 50-year return period events lasting for 24 hours each and built using the Chicago method. The future intensity-duration-frequency (IDF) curves were derived from IDF_CC tool, which is especially designed for updating these curves under a changing climate. Representative concentration pathway (RCP) scenarios are used to simulate climate change for this purpose. The future flow hydrographs are obtained through rainfall-runoff transformations and results have been inputted into the Hydrologic Engineering Center's River Analysis System (HEC-GeoRAS) (calibrated with known water elevations and flows). The calibration results give a peak flow margin of error of +2% and a volume margin of error of -24%. Water levels are better simulated at the upstream p'ortion of the Riviere des Prairies dam, with errors ranging from 16 to 95 cm. Despite the rising water, clearance remains higher than 3 meters for most of the bridges, which indicates that corresponding bridges will not be submerged or swept away. However, two bridges appear to be submerged with a water depth in range of 0.36 to 0.90 m for the first bridge (He Bizard), and 0.36 to 1.31 m for the second one (Lachapelle Bridge), depending on the model and simulated scenario. The results of the hydrodynamic simulations showed that some large flood zones were expected along the Riviere des Prairies from upstream up to the Mederic Martin A15 Bridge, as well as near the outlet. To mitigate the potential effects of flooding in the Riviere des Prairies basin, some adaptation and prevention measures have been recommended.