Dam Break Analysis Using HEC-RAS
The consequence of dam failure could be catastrophic depending on the magnitude of the failure and downstream properties. The overall objective was to estimate the dam break outflow hydrograph, route the dam break hydrograph through the downstream valley and floodplain and then estimate the inundation levels. It is therefore required to carry out dam break analysis that will help in devising appropriate management strategies and mitigate the impact effect of such disaster. The dam break analysis of the University of Ilorin dam was studied with HEC-RAS model in conjunction with Geographic Information System (GIS) and HECGeoRAS. HEC-GeoRAS was used to extract geometric information from a digital terrain model and then imported into HEC-RAS. The Steady and unsteady flow simulation of the dam break event was performed using HEC-RAS and results were mapped using GIS. The result showed that area immediately after the bridge (about 456.66-607.40 m downstream from the inline structure) and the tail end of the river reach (about 1.3 to1.6 km downstream from the inline structure) will experience greater impact of the flood for the maximum water surface profile from flood inundation. The largest flow area covered between the dam and the bridge is 1,873.8
