Flood Hazard Zonation Using Geographic Information System: A Case Study Of Way Garuntang River Basin, Bandar Lampung

Abstract Flooding is a hydro-meteorological disaster that can have an impact not only on economic losses but also threatens human life. Flooding is the event of overflowing water in potential areas due to exceeding river’s capacity, which can be predicted by using flood inundation modeling. Flood modeling could be the first step to reduce the impact of losses caused by flood disasters. Rainfall data from 5 rain gauge stations over 15 years provides spatial and temporal distribution of data that can be used as inputs in flood modeling. This study aims to investigate the performance of flood inundation modeling using rain gauge data and to derive flood hazard zonation by combining flood depth and flood velocity through hydraulic modeling and GIS. The results show that the accuracy of the depth flood inundation model based on RMSE and MAE calculation is 2.56 m and 2.19 m. in addittion the flood distribution validation results show 46.60%. Although the accuracy results for flooding show differences that can be considered, this analysis is essential for understanding and planning spatial and water management in the study area, particularly in flood risk mitigation and hydrological infrastructure planning.