Dam-break flood simulation under various likely scenarios and mapping using GIS: Case of a proposed dam on River Yamuna, India

The precision modeling of dam break floods can lead to formulation of proper emergency action plan to minimize flood impacts within the economic lifetime of the assets. Application of GIS techniques in integration with hydrological modeling for mapping of the flood inundated areas can play a momentous role in further minimizing the risk and likely damages. In the present study, dam break analysis using DAMBRK model was performed under various likely scenarios. Probable Maximum Flood (PMF) calculated for a return period of 1000 years using deterministic approach was adopted for dam break analysis of the proposed dam under various combinations of breach dimensions. The available downstream river cross-sections data sets were used as input in the model to generate the downstream flood profile. Dam break flow depths generated by the DAMBRK model under various combinations of structural failure are subsequently plotted on Digital Elevation Model (DEM) of the downstream of dam site to map the likely affected area. The simulation results reveals that in one particular case the flood without dam may be more intense if a rainfall of significant intensity takes place.