Visualisation of urban flood inundation using SWMM and 4D GIS

The areas vulnerable to flood disaster can be identified by using appropriate technologies for flood vulnerability mapping and visualisation. This paper describes the study taken up for flood inundation mapping using storm water management model (SWMM) and four-dimensional geographic information system for a part of Hyderabad city. Visualising the results from the SWMM simulation with respect to the spatial and temporal variation using Geographic Information System provides a better view of flood extension in the complex urban area. Thirty years of hourly rainfall data were available for the study from India Meteorological Department. Using this, the intensity–duration–frequency relationship has been developed and peak rainfall events have been identified. Variation of discharge with respect to time is simulated using SWMM. ArcScene is used for spatial and temporal variation of flood inundation map. These tools, combined with the fundamental concepts of hydrology were used to study the flood-prone areas along drainage network in study area to determine the spatial extent affected by the flood for varying degrees of rainfall. The results indicate that the major areas of inundation lie between Falaknuma and Malakpet, located in the downstream of the study area. The outcomes of the study will help in the management and mitigation of floods and flood-proofing of vulnerable areas.