Dam break analysis of Hirakud dam using HEC-RAS model

Abstract

Dam is indispensable hydraulic structure built across river for the aim of creating reservoir to store water. According to USACE Hydrologic Engineering Centre (HEC) Research Article 13, the failure of the dam was brought on by an earthquake, an extremely strong storm, a landslide, piping, damage to the structure, a failure of the foundation, an equipment malfunction, and sabotage. Regardless of the reason, almost all failures commence with a breach formation. In this study, dam break flow analysis for Hirakud dam was performed by assuming a hypothetical dam failure case using HEC-RAS. Data used in this study was obtained from Central Water Commission (CWC) and Shuttle Radar Topography Mission (SRTM). Study was carried out by using both Froehlich (2008) and Xu and Zhang (2009) regression models. The main objectives of this study are to route the flood wave movement, peak flood and maximum elevation of water surface due to hypothetical failure of Hirakud Dam at a distance of 0-100km in downstream and to assess the time of travel of dam break flow. Using dam geometric and elevation data the dam breach parameters are estimated in HEC-RAS as follows 1) Breach bottom width (final)=88m; 2) Breach side slope= 0.32 and 3) Breach developed time=14.50 hr.