Flood discharge analysis of Brang Ode River as a disaster mitigation effort in Kalimango Village

Abstract

Flood is a hydrometeorological disaster that often occurs in West Nusa Tenggara, especially in the Brang Ode River, Kalimango Village, Alas District, Sumbawa Regency. One of the worst floods ever happened was on December 12th, 2016, which caused several villages to be inundated and houses along the river to wash away. This study aims to obtain the peak discharge from the worst flood that has ever occurred. This model is simulated using HEC-RAS 5.0.7 and QGIS for mapping the flood inundation area. Terrain data used DEMNAS. The peak discharge is obtained from the modeling results based on the flood inundation area, validated with the flood map from the DESTANA (disaster resilient village) Community of Kalimango Village. The modeling results showed that the peak flood discharge is 950 m3/s, with the inundation area 150,752.07 m2. The actual peak flood discharge can be smaller or larger than the modeling results. It may be affected by the DEMNAS raster data accuracy.