A GIS-based fuzzy hierarchical modeling for flood susceptibility mapping: A case study in Ontario, Canada

Natural disasters such as floods have become a massive destruction of the natural environment and infrastructure because of their destructive effects and cause socioeconomic losses. In the present study, the authors attempt to present a flood hazard susceptibility map of a western region in Ontario, Canada to facilitate flood prevention and mitigation. To this purpose, a combination of the Multi-criteria decision-making (MCDM) model and Geographic Information System (GIS) has been considered. Herein, an Analytical hierarchy process (AHP) model is applied based on Triangular Fuzzy Numbers (TFNs) in a GIS environment. A total of eight quantitative criteria including elevation, land use/land cover, geology, rainfall, drainage density, slope, soil type, and distance from the river, have been used for the flood modeling. Fuzzified pairwise comparison matrices of values have determined the Importance Weights (IWs) of these criteria in Saaty’s scale. Calculating IWs, each adequate criterion's impact on flood risk was investigated using the fuzzy AHP method. The Consistency Index of each pairwise comparison of measures has been checked. Based on the calculated IWs results of each criterion, the elevation, land use/land cover, and geology criteria play significant roles as the most eminent flood occurrence criteria. In addition, the results demonstrate percentages of flooded areas and the flood hazard index of the study area.