Inundation Risk Assessment in Urban Rail System of Mega-City via GIS-Based Multi Criteria Decision Approach

Abstract

The urban rail system (URS) is a critical component of public transport, providing important social and economic services in megacities. Increasing frequency and severity of urban inundation may cause functional disruptions in URSs; therefore, understanding the inundation risk of URSs is a prerequisite for risk management in cities. This present study incorporates the Fuzzy Analytic Hierarchy Process (FAHP) into a Geographic Information System (GIS) and performs VIseKriterijumsa Optimizacija I Kompromisno Resenje (VIKOR) approach, which uses the performance values of determined regions in the study area, to evaluate the inundation risk of the URSs in Istanbul. For the inundation risk analysis, 10 hazard criteria and 12 vulnerability criteria were identified. According to FAHP-based GIS results, the southeast of the European side and the southwest of the Asian side of the study area were determined to be the most sensitive regions. VIKOR results emphasized that inundation risk was higher in Atas,ehir, Kad & imath;koy, and Tuzla districts. Additionally, the results showed that more than 60 % of URSs were highly exposed to the risk of inundation, and this result was more pronounced in the Kad & imath;koy district. According to the sensitivity analysis results, it was determined that the most sensitive criteria in the inundation risk analysis were Daily Maximum Rainfall and Population Density, which had the highest weights for hazard and vulnerability. This research holds substantial importance regarding inundation warning and prevention in the Istanbul URSs, offering a theoretical framework for evaluating inundation risk in other metropolitan areas in terms of the data and methods used.