Application HEC-RAS Model to Simulate the Flood Wave Due to Dam Failure

In this paper, the flood wave resulting from the hypothetical failure of Haditha Dam on the Euphrates River, Iraq, was simulated. The length of the study reach was about 124.4 km, beginning from Haditha Dam and ending at Hit City. Numerical software (HEC-RAS) which is based on Saint-Venant equations was applied to get the main parameters of the flood wave at certain cross sections. The results showed that Max. discharge at the dam site was 202547 m3/sec which decreased nonlinearly at the other cross sections until it was 111340 m3/sec at the reach end. Also, Max. water level decreased nonlinearly from 133.13 m at dam site to 82.76 m at Hit City. The reduction ratios for discharge and water elevation were about 45% and 38% respectively. Statistical analysis was performed to develop the best formulas for estimating Max. elevation and Max. discharge depending on distance and time. Also, it was found that the flood wave takes long time to achieve the highest level for stations located farther from the dam site, thus these stations were considered an accumulation zone of the flood.