FLOOD INUNDATION SIMULATION USING A LARGE-SCALE RAINFALL-RUNOFF-INUNDATION MODEL - EFFECTS OF TOPOGRAPHIC DATA CORRECTIONS -

Abstract

 This study uses the Rainfall-Runoff-Inundation (RRI) model applied to the entire Japan with 150-m resolution to conduct large-scale flood simulations for the Kumagawa flood in 2020 and Typhoon Hagibis in 2019. By reflecting actual river cross sections and elevation data corrections, the river water level and inundation simulations were improved for the 2020 Kumagawa flood. It was important to remove the effects of river channels reflected in the topographic data and adjust the elevation corresponding to the surrounding floodplain levels before explicitly embedding actual cross section data into the model. In the case of Typhoon Hagibis, the simple modeling of floodgates and additional parameter setting in the floodplain were important.