Social, economic and environmental assessment of urban sub-catchment flood risks using a multi-criteria approach: A case study in Mumbai City, India

Floods have an increasing impact on cities, encompassing the management of the water cycle by integrating multiple disciplines of engineering, social, economic and environmental sciences. This study focuses on deploying site specific spatial strategies considering human interactions towards assessing urban flooding. Initially, two surface runoff models were implemented at a high spatial resolution to estimate the water availability and infiltration capacity of the Mumbai city (India). To this end, first, the major watersheds were delineated corresponding to four major rivers and the coupling of hydrological and hydraulic models to obtain the spatial flood extent. Subsequently, non-heuristic criteria were evaluated to determine flood hazard maps. Then, spatial risk maps were identified corresponding to social, economic, environmental and infrastructural impacts to deploy site specific strategies for flood mitigation. In addition, a correlation analysis was performed for the sub-catchment to understand the dependency within the risks. Management interventions to reduce these risks at especially vulnerable sites were identified, including stormwater harvesting, flood risk management, and water reuse during dry seasons. Therefore, this study bridges the gap between modelers and decision planners, in order to embrace flooding as an opportunity instead of a disaster.