Numerical Modeling of Extreme Flooding for Flood Risk Assessment in the Tra Bong River Basin, Vietnam

Abstract

Flooding and inundation are of the most concerns in Vietnam. Many extreme floods have been occurring in Vietnam frequently, especially during the period of 1999–2009. Considering the impacts of flooding plays an important role in mitigating and adapting to flood risks. In this study, a rainfall-runoff model, two hydrodynamic models, and a coupling model were successfully applied as effective tools to simulate flooding and inundation in the Tra Bong River Basin, which is located in central Vietnam and considered as an ungauged basin. These models simulated the high flows accurately by depicting all of the peak flow discharges in accordance with observed high flows. The low flows were also simulated fairly well. In general, there is a good fit between the observed and simulated hydrographs for both calibration and validation. According to the model performance, 80% of the floodplain area would be flooded during the future extreme flood event. Eventually, the model results indicate that the integration of these models is significantly suitable for the flood risk assessment in the basin.