Flood Damage Assessment of a River Basin Using HEC-GeoRAS

Flood is one of the most catastrophic events among the many different types of natural hazards. It seriously harms people, property and places used for industry and agriculture. A GIS extension called HEC-GeoRAS provides a series of steps, tools and options for preparing river geometry grid data for input into HEC-RAS, which is utilised to create the final inundation map. The DEM and a Basin Landuse Map must be provided as input data for the preparation of river geometry using HEC-GeoRAS model. The flood hydrograph is derived from the synthetic unit hydrograph and probable maximum precipitation, and the PMP value obtained was about 157.3 cm. The total area of the basin was found to be 787 km2 in which the inundated area was 274.279 km2, which is about 35.851% of the total area.