The Effectiveness of Flood Damage Reduction Measures in the Montreal Region

Abstract

The purpose of this study is to assess the effectiveness of two flood damage reduction measures – designation and dyking of floodplains. The study was carried out in four Quebec municipalities located on the shores of Lac des Deux-Montagnes and Riviere des Mille-Iles, namely Sainte-Marthe-sur-le-Lac, Saint-Eustache, Rosemere and Bois-des-Filion. Criteria for selecting the study areas were: area of the flood-risk zone, presence or absence of dykes, presence or absence of buildings, and availability of data. The study areas were selected with the help of flood risk maps of the Greater Montreal region. In each area, information on the number of buildings and their economic value was taken from the municipality's property assessment database. Trends in the occupancy and value of floodplains were identified and compared. The results of the study show that, as in other regions of Canada, flood damage reduction measures based on designation and mapping of floodplains have had no impact on occupancy, have failed to reduce flood damages, and have not even halted increases in such damages.