A Dam Break Analysis of Damanganga Dam Using HEC-RAS 2D Hydrodynamic Modelling and Geospatial Techniques

The dam is the inline structure constructed over the river connecting the storage area to the downstream river catchment area. Large dam constructs serve multipurpose objectives like irrigation, hydropower generation, and water supply for residential, commercial, and industrial use. Though dams have many benefits, the threat of dam break always remains, either due to a large amount of rainfall in the upstream catchment, earthquake, structure failure, etc. To understand the dam breach scenario and find out the inundation extent, water surface elevation, flow velocity, and wave arrival time, a dam breach study is needed. It contributes to reducing loss of life and damage by guiding the preparation of emergency action plans (EAP). This paper describes the analysis of piping failure of the Damanganga dam, Gujarat, India, using the Hydraulic Engineering Centre’s River Analysis System (HEC-RAS) 2D hydrodynamic modelling and geospatial techniques. Inflow hydrograph, Digital Elevation Model (DEM), topography, and area capacity curve of Damanganga reservoir have been utilized to build a 2D hydrodynamic model. Froehlich equation was used to estimate dam breach parameters. Water surface elevation, flow depth and velocity, arrival time, and inundation area were calculated. The inundation area is 153 km2, and the number of affected villages including cities is 48. This study helps the site’s administrative authority, and the dam owner develops EAP and flood mitigation.