Spatial Modelling Of Flood Inundation and Risk: Case Study Mangottong River Area, Sinjai Regency

Abstract

Flood is one of the natural disasters that often happens in Indonesia due to high rainfall. Sinjai is one of the regencies in South Sulawesi which had been severely hit by flood. It happened in 2006 which caused many losses and victims, especially in the capital regency due to the overflow of Mangottong River. The objectives of the research were to develop and simulate spatial modeling of flood inundation, analyzing hazard, vulnerability, and risk level of flood in Mangottong River area. Spatial modelling of flood inundation is using GIS based DEM and flood volume data, while the risk was analyzed by combining of hazard and vulnerability components. Inundation model validation results showed a fairly good accuracy for the flood depth in 2006 simulation with the value of R2 was 0.72. Flood hazard level based on water depth of 25 year return period simulation model result showed that most area of North Sinjai District are in low and middle class, while East Sinjai District are in high class of hazards. Flood vulnerability and flood risk level showed North Sinjai District has a higher percentage of area than East Sinjai District for all classes.