GIS-Based Multi-Criteria Decision Making And Fuzzy Logic Approaches For Multi-Hazard Flood And Flash Flood Risk Exposure Assessment In Sinop Province, Türkiye

Abstract

A flood refers to the sudden and excessive rise in water levels in a riverbed due to excessive rainfall, while an inundation refers to the spread of water rising from the riverbed, inundating the surrounding area. The haphazard construction of housing in river basins to meet the needs of the growing population increases the number of people exposed to floods and inundations, while also causing greater property damage. In this study, the flood and inundation risk exposures of Sinop province, which has recently been exposed to flood and inundation disasters due to the effects of climate change, were determined using Geographic Information Systems (GIS), multi-criteria decision-making analyses, and Fuzzy Logic methods. Different parameters, such as slope, rainfall, distance from the river, aspect, and land use, were used to determine sensitivity values. Membership functions of the parameters were assigned according to the characteristics of the research area and the literature review. The overlay process was performed using the GAMMA and AND operators. Flood, inundation, and integrated flood and inundation risk exposure value maps were obtained from the research. Risk exposure values ​​indicate areas with high, medium, and low susceptibility to flood hazards. It is observed that flood risk exposure is significantly increased in areas close to rivers and with low slopes. The high-risk category of settlements resulting from land use necessitates the implementation of preventative measures in these areas. According to the findings, flood risk exposure in Sinop province is not spatially homogeneous, but is concentrated in sloping and high-altitude areas, as well as in basin and valley bottoms.