Topography based flood susceptibility prediction by using the GIS platform and historical flood data of lower Ajay river basin

Abstract

Flood inundation mapping of lower Ajay River basin was implemented in the Geographic Information System (GIS) using the historical flood data and statistical frequency analysis by following the Gumbel probability distribution method. The historical data proofs the magnitudes of the flood intensity by various recurrence intervals on the basis of the projected flood height and present topographic character inundation mapping done in the GIS platform. Most importantly, due to the lack of hydrological past gauge height data are used in different gauge stations for projecting flood inundation mapping. Open access SRTM DEM data provides the topographic characteristics of the basin region and by the combined data of flood magnitudes and topographic data, flood inundation-mapping may help in the identification of the hazards prone area. The study area is regularly flooded and due to high population density huge damage takes place. So for the better management planning and risk estimation, hazards mapping is essential. Flood hazard mapping is done on the basis of 2, 10 and 25-year return period. The result depicts that 44% area in the lower part of the basin is flood prone and almost more than 474000 population and almost 59000 child population will be affected during the flood. The model is validated followed by overall accuracy assessment and KAPPA statistics methods and both results above 80% proof the model suitability.