The simultaneous occurrence of river flooding and storm surges can potentially exacerbate flood risks compared to individual occurrences. This study investigates compound flooding from severe typhoons in a data-scarce coastal river catchment using an integrated numerical modeling framework (rainfall-runoff, 1D/2D hydrodynamic, and storm surge model) combined with satellite precipitation and imagery. Our results reveal that compounding impacts increase inundation in low-lying areas, with a 4.67% rise in flooded extent and an 11.63% increase in maximum water depth. Potential hazard maps under a hypothetical super typhoon scenario indicate even greater risks, with up to 30% more inundated area and 50% higher maximum water depth than the most extreme historical event. The paper highlights two key points: (i) riverine flooding-storm surge interactions must be considered to avoid underestimating risks; and (ii) the developed framework offers a pratical approach for other river catchments facing similar challenges due to limited hydrological records.
Trinh et al. (Thu,) studied this question.