Hydrodynamic simulation of a dam breach of Cipanas Dam using HEC-RAS 5.0.5

Abstract

Dams have many benefits for living creatures. On the other hand, dam breaks may also become disasters that cause potential losses of life and property. The Cipanas Dam has been planned for construction in Sumedang, West Java, and will have a storage capacity of up to 210 million m3. The area downstream of the Cipanas Dam contains many major infrastructures such as the Cikopo-Palimanan Toll Road and Kertajati International Airport that can be impacted by dam breach floods. This study analysed Cipanas Dam breach flow using HEC-RAS 5.0.5. The simulation assumed that a dam breach occurred through piping with 5 scenarios of breach time formation. The simulation resulted in flood hydrographs and flood inundation maps of the area downstream of the dam. The findings revealed that a breach formation time of 1 hour had the greatest flood effect. The maximum flood discharge was 38, 823.3 m3s-1 with a released water volume from the reservoir of 178, 814, 590 m3. The arrival time of the flood at the Cikopo-Palimanan Toll Road Bridge was 3 hours 45 minutes after the breach occurred, and the maximum flood depth was 15.78 m. Kertajati International Airport was not affected by the flood discharge.