2020 Volume 76 Issue 2 Pages I_457-I_462
This paper discusses the possibility of introducing a new type flood control facility, called "running water type retarding basin (RWRB hereafter)", in the upper Abukuma River where the largest record flood occurred in 2019. Unlike a usual retarding basin that is installed in the plains to store flood water horizontally, RWRB is designed to flow excess flood water over narrow floodplain along a steep upper river channel by premeditated river overflow. In this study, adjoining two narrow paddy, having the total length of 4000 m and the total area of 100ha, were selected for a numerical model simulation of RWRB. Three structures were installed in the model; a culvert connecting the two areas to enlarge the distance of water running; a side-channel spillway for inflow at the upper end, the crown of which is HWL+0.5 m; and a drainage gate for outflow at the lower end. Flood control capability of the model RWRB obtained from a numerical flow simulation under the hydrological condition of 2019 flood suggetsed that a group of RWRB installed on the narrow floodplains along the upper Abukuma River would effectively decrease the peak of flood hydrograph.
PROCEEDINGS OF HYDRAULIC ENGINEERING
