Simulation of Saguling Dam Break Using the HEC-RAS Software

The Saguling dam is built on the cascade system of the Citarum river. The Saguling dam is located upstream of the system over the Cirata and Jatiluhur dams. Besides having the many benefits (irrigation, recreation, flood control, water storage, etc.), the Saguling dam saves the risk of big dangers in the case of the failure. The general failure or dam break reason of the Saguling dam can happen due to the internal and external factors. The internal factor is an occurrence of breach in the dam body that causes the process of piping in the top, center and low part of the dam body. Another internal factor is the mal-function of the spillway if the water discharge is too much. The external factor is the big flood discharge that can cause the overtopping. This research intends to conduct the simulation of dam failure or dam breaks in the Saguling dam. The methodology consists of data collection for the material of dam break analysis 2D like hydrology data, digital map, and technical data of dam. Then, the collected data was analyzed using the HEC-RAS software. Considering the possibilities of failure risk of Saguling dam, the simulation analysis of dam failure or dam break was performed for some scenarios and their impacts on the downstream part of the dam. The results show that the Saguling dam with the overtopping scenario has the worse impact than the piping scenario with the maximal inundation area and the possibility area of 19.39 km2. The simulation of the Saguling dam failure or dam break produces the flood discharge whose flow will reach the Cirata reservoir in 3 hours.