A STUDY ON THE FLOOD CONTROL COUNTERMEASURES BY THE STORAGE FACILITIES IN THE LEFT BANK BASIN OF THE ROKKAKU RIVER AND THE TAKEO RIVER

Abstract

 Torrential rain disasters occurred in Rokkaku River watershed in 2019 and 2021. Especially, in the left bank basin of midstream of the Rokkaku River and the Takeo River, the tributary of the Rokkaku River, enormous damage occurred by the inland water flooding. This area is vulnerable to the inland water flooding so that the riparian work so far in the river cannot solve the existing problem of the watershed. In this study, storage facilities of the watershed are investigated for the solution. Focusing on the fact that the wide farmlands spread in the lowland region of the study area and there are several major irrigation reservoirs in the mountainous region of the same area, flood control countermeasures considering the inland water regulation reservoirs and the irrigation reservoirs are studied using 1D and 2D analysis of the flood and inundation. As a result, there are effects to decrease the beginning inundation depth by the storage facilities against the same torrential rain in 2019. It is clarified that there are some differences between the location even in the same watershed.