Future fluvial flood risks in Central Vietnam assessed using global super-high-resolution climate model output

Fluvial flood risks are explored at the Vu Gia-Thu Bon River system in Central Vietnam based on a coupled hydrological-hydraulic model combined with design storm hyetographs constructed based on heavy rainfall downscaled from the output of a state-of-the-art super-high-resolution (20-km mesh) global climate model simulated under greenhouse gas emission scenario A1B. The results indicate that intensified rainfall due to future climate changes (2075-2099) will lead to higher flood risks in the fluvial plains, especially in the lower areas of the river system. The potential extent of inundation caused by a 25-year return period flood in future climate patterns will increase by approximately 150% compared with those produced by the most severe flood in the present-day climate (1979-2003). Moreover, the flood risks induced by a 10-year return period flood tend to be slightly more severe than that of the 25-year return period in the present-day climate.