SIMULATION OF ARAKAWA MIDDILE STREAM FLOOD DUE TO TYPHOON 19 2019

Abstract

 This paper presents the simulation of the flood by Typhoon 19 October 2019 using two flood models. Firstly, the discharges around Tokigawa and Oppegawa rivers were reproduced by a distributed rainfall-runoff/flood-inundation model. The simulated discharges were in good agreement with observed discharge. Then, the inundation simulation with 5 m resolution elevataion data was carried out using Fugaku super computer. The detailed inundation process including the effect of second dike was reproduced well which shows the effectiveness of fine resolution simulation. Finally, the effect of the climate change on the catchment average 24 hour rainfall over Arakawa river was investigated using d4PDF. The 24 hour rainfall–return level was plotted using the data which shows the increase of the rainfall intensity toward the future.