Estimation of breach outflow hydrograph using selected regression breach equations

Abstract Embankment dam is commonly built in Malaysia as it provides essential benefits to the local population, such as agricultural activity and flood control measures. However, the release of high potential energy by the impoundment imposes risk of catastrophic event during the dam failure. Therefore, estimation of flood arrival time under dam break event can be beneficial as primary information using numerical model to simulate the breaching process of the embankment dam. The purpose of this study is to establish dam breach profile of Temenggor Dam in predicting breach outflow hydrograph. A few selected regression equations for breach parameters will be tested namely Froehlich, Macdonald and Langridge-Monopolis and Von Thun and Gillete. One-dimensional dam break modelling were performed based on the calculated breach parameters for overtopping and piping failure. Hydrologic Engineering Center’s River Analysis System (HEC-RAS) software is used for the dam break analysis. Results obtained from the study indicated that overtopping failure yields the highest peak breach flow of 202,099 m3/s, compared to piping failure’s highest peak discharge of 201,126 m3/s.