Evaluating the Efficacy of Different DEMs for Application in Flood Frequency and Risk Mapping of the Indian Coastal River Basin

Floods are among the most occurring natural hazards that cause severe damage to infrastructure and loss of life. In India, southern Gujarat is affected during monsoon season, facing multiple flood events in Damanganga basin. As basin one data-scarce regions, evaluating globally available dataset for risk mitigation studies crucial. present study, we compared four open-source digital elevation models (DEMs) (SRTM, Cartosat-1, ALOS-PALSAR, TanDEMX) hydrodynamic (HD) modeling mapping. The simulated HD using HEC-RAS v6.3 were calibrated by adopting different roughness coefficients based on land-use land cover, observed water levels at gauge sites, peak depths plain. contrast previous Purna river (the neighboring Damanganga), study shows Cartosat-1 DEM provides reliable results with depth. Furthermore, model was used determine corresponding 10, 25, 50, 100-year return period floods calculated Gumbel’s extreme value (GEV) log-Pearson type III (LP-III) distribution techniques. Comparing obtained periods revealed LP-III method gives more estimates peaks lower periods, while GEV comparatively higher floods. data techniques crucial developing plans practical implications.