A Hybrid Approach of Integrating HEC-RAS and GIS Towards the Identification and Assessment of Flood Risk Vulnerability in the City of Jackson, MS

Integration of flood risk assessment information in the urban planning process plays an integral role in the effective management of flood risk mitigation measures. The present study develops a hybrid approach in identifying flood risk zones and assessing the extent of impact of the hazard by integrating HEC-RAS and GIS technologies. This GIS-based approach, which allows visualizing and quantifying the results in a spatial format, was applied to the City of Jackson, MS. A 200-year magnitude flood event, which was experienced by the study region in 1979, was simulated to expose the vulnerability of the current infrastructure of the region whose developmental codes are bound to a 100-year magnitude flood event. The results indicated the efficiency of the developed hybrid approach in modelling the flood scenario, visualizing the spatial extent and assessing the vulnerability of the region. The vulnerability assessment from the 1979 flood event simulated by HEC-RAS model presents the intensity of risk to which the City of Jackson is exposed with its major transportation corridors (I-55, Highway 80) and numerous critical facilities getting affected by flood waters. By generating quantified estimation of inundation depth levels at any point of interest in the study region, which is absent in the previous research, this study attains utmost significance. Flood risk assessed by simulating higher magnitude flood events using such hybrid approach magnifies the vulnerability of the region and reinforces that any land use planning decisions in floodplains should make informed choices by incorporating scientifically derived information in their decision making process.