Development of a 2D hydrodynamic model for inundation assessment and flood early warning system: a case of depressed Ghed region, India

Abstract Ghed region is located in the deep western part of Gujarat state, having the cup shape geometry. The Ozat River begins near the Gir forest's hilly part and moves towards the river mouth near Navi Bandar. The part before the river mouth is called Ghed, near the coastal line. The inundation in this region occurred due to higher coastal line and cup shape geometry with an area of more than 200 km2. This research emphasized early warning of the local community aside from the region during the peak flow condition. The hydrological engineering centre-river analysis system software developed the hydrodynamic model for FEWS (flood early warning system). The model has been validated with observed water depth data at four locations from the river reach area for more precision. In this regard, various statistics have been performed to compare the observed and modelled data. The result depicts the 19 h of leg time available to evacuate the local community. After that, water takes 115 h more time to reach the river mouth due to cup-shaped region filling. This research helps the administration with the decision-making system and establishes new hydraulic structures.