ANALISIS BANJIR BENGKULU TAHUN 2019 DENGAN MENGGUNAKAN SOFTWARE HEC-RAS 5.0.7

Floods are natural disasters that occur almost every year when the rainy season is coming. On April 27, 2019 Bengkulu Province experienced a devastating flood and caused significant losses in material and non-material terms. The Air Bengkulu River is one of the causes of flooding in Bengkulu Province which crosses Central Bengkulu Regency and Bengkulu City. There are many ways to anticipate or prevent floods, on of them is the mitigation method, by making a prediction map of flood inundation areas. In this study, prediction modeling of flood inundation in the Air Bengkulu River was carried out using permanent or steady discharge with the help of software ArcGIS 10.3, HEC-GeoRAS 10.3, and HEC-RAS 5.0.7. The purpose of this research is to model the prediction of flood inundation and to know the prediction of the area of flood inundation. In addition, this study also aims to determine flow velocity, water level, and differences in flooding or flood inundation at maximum and minimum tide. The prediction results of the flood inundation area obtained when the flow rate is 442.2 m3 /s and the maximum tide is 0.32 m in Bengkulu City is 1.415275 km2 and Bengkulu Tengah Regency is 2.685689 km2 . Meanwhile, when the flow rate is the same with the minimum ebb of -0.223 m, the prediction of inundation in Bengkulu City is 1.409415 km2 and in Bengkulu Tengah Regency it is still 2.685689 km2 .