Abstract

With the rapid rise in flooding events induced by climate change across the globe, effective flood management strategies through modelling have garnered attention over the years. In the present study, we propose a holistic hydrodynamic flood modelling framework to derive the flooding extent. Various hydraulic scenarios are integrated into the framework which consider different combinations of cross-section and lining material options along the river channel for this purpose. A 3-way coupled flood model has been developed in MIKE FLOOD platform, over Mithi river catchment an extremely flood-prone area in Mumbai, the financial capital of India. Flood influencers such as precipitation, flows through the channel, overland, storm-water drains, and tidal influences are considered to generate flood inundation and hazard maps for the scenarios. The dearth of data in the model is met by implementing alternate robust procedures to compute the design values of the influencers. Subsequently, the maps are derived for different return periods of design precipitation, tidal elevation and streamflow values to identify the most desirable scenario. The proposed framework efficiently determines that the scenario having trapezoidal river cross-section with concrete lining material maximizes the decrease in spatial extent of flood in comparison to the other scenarios. This user-friendly generic approach can be potentially executed as an effective flood mitigation option in thickly populated and socially vulnerable regions where lack of space limit the implementation of structural measures for flood management. The framework can prove instrumental particularly for the developing and under-developed countries where application of these strategies is hindered by inadequacy of data.