Impact of climate change on flood inundation in a tropical river basin in Indonesia

Abstract Climate change will have a significant impact on the water cycle and lead to severe environmental problems disasters in humid tropical river basins. Examples include basins Sumatra Island, Indonesia, where coastal lowland areas are mostly composed of peatland that is wetland environment initially sustained by flooding from rivers. may alter frequency magnitude flood inundation these areas, disturbing its carbon dynamics damaging agricultural plantations. Consequently, projecting extent due future events considered important for basin management. Using dynamically downscaled climate data obtained Non-Hydrostatic Regional Model (NHRCM), Rainfall-Runoff-Inundation (RRI) model was applied Batanghari River Basin (42,960 km 2 ) project latter part twenty-first century. In order obtain reasonable estimates inundation, this study compared two bias correction methods: Quantile Mapping (QM) method combination QM Variance Scaling (VS) methods. The results showed improved simulated flow duration curve (FDC) RRI model, which facilitated comparison with FDC using reference rainfall data. However, high spatial variability observed daily 15-day remained as variation bias, could not be resolved simple alone. extreme variables, such annual maximum volume, were overestimated By introducing QM-VS correction, cumulative density functions discharge volumes improved. findings also increase region; example, volume corresponding 20-year return period 3.3 times. management measures, land use regulations plantations conservation, should therefore consider increases depth area, extents under scenario presented study.