Probabilistic flood inundation mapping for sparsely gauged tropical river

Abstract

The present study focuses on the preparation of a flood hazard map for a sparsely gauged tropical river. Nagavali Basin in the Indian states of Andhra Pradesh and Odisha was chosen for conducting the case study because it has only one gauging station and frequency of flood occurrence is very high. To overcome the data scarcity, streamflow data for ungauged site was simulated through HEC-HMS-based distributed hydrological model using gridded precipitation data. The streamflow for various recurrence interval was predicted using the most appropriate statistical distribution. The predicted streamflow was applied as the boundary condition for HEC-RAS-based hydraulic model to prepare a probabilistic flood inundation map. In this research, comprehensive methodology was provided for estimating design flood at a sparsely gauged river. The outcomes of the study can be facilitated in non-structural flood mitigation measures for both society and policymakers. The flood hazard map also supports designing hydraulic structures for sustaining during a major catastrophe.