Assessing flood hazard mapping using AHP and GIS in a tectonically active region

This study focuses on the development of a flood hazard model for the Phoenix River drainage basin, located in the northern Peloponnese region of southern Greece. In situations where runoff exceeds the drainage system's capacity, five key factors have been identified as the most significant in influencing it. These factors include slope, elevation, hydro-lithology, distance to streams, and land cover. The Analytical Hierarchy Process (AHP) was integrated with Geographic Information System (GIS) to facilitate the assessment of the chosen factors employed in the production of the flood hazard assessment map. The hazard zones depicted on the generated flood hazard map underwent an evaluation process involving uncertainty analysis. Additionally, the verification of the map was carried out through the utilization of frequency ratio analysis and examining previous flood events. The research findings indicate that the areas with the most pronounced risk of flooding are predominantly situated in the northern and central regions of the drainage basin. This heightened hazard is attributed to a combination of factors, including flat morphology, proximity to the hydrographic network, the presence of semi-permeable formations on very gentle slopes, urban land use, and the presence of previously burnt areas. The uncertainty analysis indicates the reliable predictions produced by the applied method. The verification analysis confirms a satisfactory correspondence between the flood hazard zones on the map and the actual spatial occurrence of flood events. The methodology employed in this study was applied effectively in various projects, including flood hazard assessment mapping, flood hazard mitigation, and land use planning.