Flood hazard zone mapping incorporating geographic information system (GIS) and multi-criteria analysis (MCA) techniques

Abstract

Flood is one of the most common natural disasters worldwide and has caused serious harm to humans, socio-economy and the environment. Identification and classification of flood hazard areas is therefore essential for flood management and risk decision-making which attempt to combat this challenge. This study selected eleven flood hazard conditioning factors as evaluation criteria, integrated geographic information system (GIS) with three multi-criteria analysis (MCA) techniques, viz. the analytical hierarchy process (AHP), technique ordered preference by similarity to the ideal solution (TOPSIS), and ordered weighted averaging (OWA), to form a GIS-MCA framework for analyzing the spatial distribution of flood-prone areas. Its application in the Dadu River basin, China derived a total of eleven flood hazard maps across the basin, and their analysis and comparison results demonstrated the spatial distributions of flood-prone areas based on various GIS-MCA approaches and their overlap situations, and indicated that hazard class distribution patterns of the AHP, TOPSIS, and OWA (α = 1) maps are similar, and Luding, Yuexi and their nearby areas are the highest hazard zones, where should be concerned on firstly under the condition of limited resources. To validate the three MCA methods, the AHP, TOPSIS, and OWA (α = 1) maps were compared with the historical flood disaster ranges. The verification results exhibited that the largest proportion of historical flood disaster ranges fell into the high and highest hazard levels in the three maps, and shown the resultant flood hazard maps are scientific, rational and consistent with the actual situation. The GIS-MCA approach is a powerful and feasible guidance tool for conducting flood disaster management studies, and a reference for future more efficient flood management and risk decision-making in the basin.