Flood hazard mapping using geospatial techniques and satellite imagesa case study of coastal district of Tamil Nadu

In recent years, extreme rainfall events have resulted in several devastating floods especially in the east coast of Tamil Nadu, India. The main aim of this study is to identify the flood hazard zones in Cuddalore district by integrating spatial distribution of extreme rainfall events, slope, drainage density, soil, and geomorphology. Moderate Resolution Imaging Spectroradiometer satellite data was used to delineate the flood inundation area for the flood event which occurred in 2010 to validate the derived flood hazard zones by using geographical information system (GIS) and satellite images. The ground truth points were collected from the field to validate flood hazard zones, and it was identified that 92% of results were matched with hazard zones. Highly vulnerable blocks including Cuddalore, Kattumannarkoil, Keerapalayam, Kumaratchi, Kurinjipadi, Melbhunagiri, and Parangipettai were identified in Cuddalore district. From this study, it was also identified that nearly 45% of the total area of 3678km(2) were inundated during the flood time. This present study will be a very useful tool and a resource for the policy planners and coastal planners to make effective decisions towards mitigation measures in flood-prone areas in the coastal districts.