Analisis Penelusuran Banjir Akibat Keruntuhan Bendungan Gondang

Abstract

The construction of a dam, aside from being useful for the life sustainability of people around the reservoir, also has the potential of great danger if it collapses. With the development of civil society in the downstream area, the impact will be even greater if there is a dam breach. This study aimed to analyze the water flow pattern downstream at Gondang Dam after the breach with the cause of piping. The dam breach analysis was conducted with the HEC-RAS program. This study simulated the dam breach with piping scenarios by inserting certain breach parameters to obtain flood hydrograph and water level hydrograph. Gondang Dam breach in one of piping scenario produces a maximum flow rate of 92,603.62 m3/s and the maximum water level is +557.251 m. Ganten village, Kerjo district is ±200 m from the dam which is used as a reference for flood routing. The maximum flood depth from the residential elevation is 27.5 m with a duration of 31 hours from the beginning of the flood until it runs out.