DEVELOPEMENT OF A MACRO-SCALE RAINFALL-RUNOFF-INUNDATION MODEL FOR LARGE-SCALE APPLICATIONS WITH FAST COMPUTATION

Abstract

 Large-scale flood analysis using ensemble climate change data requires a hydrological model that can simulate runoff and inundation with high speed computation. The objective of this study is to develop a 1K-RRI model that can solve runoff and inundation at the macro scale at 1 km resolution. The model was constructed by upscaling a nation-wide RRI model at 150 m resolution. Applying the RRI model to the macro scale without particular care will cause problems such as the inability to distinguish between different runoff processes of mountainous and plain land uses within the same grid cell. Therefore, we improved the RRI model by upscaling the average gradient and area of the mountainous and plain land uses and calculating each runoff component. The 1K-RRI model was compared with the original 150 m resolution model and a model upscaled directly to the 1 km resolution. We found that the 1K-RRI model can reproduce the runoff responses better compared to the one just upscaled without any particular attention.