Flood analysis in the nuta river basin during the heavy rain in july 2018

Abstract

In July 2018, heavy rainfall in western Japan caused severe flood damage. Overflows and several levee breaches in tributaries occurred in the Nuta River basin, which flows in the eastern part of Hiroshima Prefecture, and the area suffered flood inundation. This study conducted on-site observations in the Funaki district, where flood damage was significant, and investigated the behavior of flood water during flooding. Subsequently, we discussed flood flow characteristics and the effect of upstream Fukutomi and Mukunashi Dams from the obtained water-level data and runoff analysis results. Horizontal two-dimensional simulations were used to show the influence of tree growth on the flood flow.