Assessment of Flood Risk Mitigation Measures Based on Economic and Social Performance: A Case Study From Ağva, Türkiye

Abstract

In this study, flood mitigation measures, both structural and nature-based ones, are proposed, and their social and economic performances are quantified using a multi-criteria decision analysis framework. The effectiveness of the selected measures is evaluated through numerical modeling. As a case study, flood inundation areas and flood hazard maps are determined in the Ağva District of Istanbul using high-resolution LIDAR data in a 2D hydrodynamic model for different flood scenarios. The numerical model is calibrated against measured discharges at the river gauging station in the river basin. For the social and economic assessment, a total of seven criteria are assessed: number of affected inhabitants, number of affected cultural items, number of public institutions under flood, expected annual damage, investment cost of measures, annual maintenance cost, and benefit–cost ratio. The overall score of each flood mitigation measure alternative is computed, and their performance is compared for different strategies. For our case study, the implementation of a levee exhibits the highest economic and social performance for flood risk management.