Abstract
Bili-bili Dam located in Sulawesi Selatan, Indonesia was built as a multipurpose dam. However, it has lost its sediment capacity by deposit resulted from the collapse of Mt. Bawakaraeng. Since then, there has been a criticism that the construction of Bili-bili Dam was not appropriate at the very place. Without Bili-bili Dam, sediment in the river by the collapse would have possibly triggered serious sediment disasters in downstream areas. We evaluate effectiveness of Bili -bili Dam as a sabo dam which prevents sediment from flowing downstream. We simulate one-dimensional riverbed variation of the Jeneberang River and two-dimensional flood in the downstream areas of Bili-bili Dam. The results of one-dimensional riverbed variation simulation show that 22 million m3 of sediment would flow downstream in twenty years and the riverbed would rise up to 10 m. The results of two-dimensional flood simulation show that the floodwater would inundate 68 km2 of the areas including highly populated residential areas. Therefore, Bili-bili Dam functions effectively as a sabo dam.
