Author(s): Ritsuki Shimizu, Tatsuhiko Uchida, Yoshihisa Kawahara

Linked Author(s): Yoshihisa Kawahara

Keywords: Heavy rainfall in July 2018; The Nuta River; Rainfall-Runoff-Inundation (RRI) model; 2D numerical simulation; Tree growth;

Abstract: The heavy rainfall from 5 to 7 July 2018 in the western Japan have caused severe flood damage. The Nuta River basin is one of the most suffered areas from the flood inundation, which was induced by overflows, bank erosion, and several levee breaches in the tributaries. We applied the Rainfall-Runoff-Inundation model to the river basin to discuss the rainfall runoff characteristics comparing with the several scenarios for the operations of the Fukutomi and Mukunashi Dams. 2D flood flow simulation was carried out in the damaged reach of the river, Funaki district, to clarify the flow resistance of tree growth. The 2D numerical simulation confirmed that the increase in water level in the reach is attributed to the flow resistance by tree growth in addition to the large discharge induced by the extremely heavy rain.

DOI: https://doi.org/10.3850/38WC092019-1332

Year: 2019