2024 Volume 80 Issue 17 Article ID: 24-17147
At the mouth of the Hojo River drainage located in the central part of Tottori Prefecture, river mouth blockage due to the formation of a sandbar frequently occurs. In this study, on-site experiments were conducted to demonstrate a method of flushing a sandbar by operating a diversion weir, which is a pneumatic rubber-coated fabric weir located 2.2 km upstream from the mouth. Experimental conditions were set up focusing on the upstream water level and flow rate with the opening and closing of well weirs and sluice gates, the water level at the mouth of drainage before overtopping, and the height of the sandbar. Preliminary numerical examinations were also conducted whether sandbar flushing can occur. The initial ratio between the water level and the crown height of the sandbar and the rise of the water level at the river mouth after the operation of the diversion weir are important factors in the possibility of sandbar flushing, therefore these parameters were reflected setting in the initial conditions of the field experiments. The feasibility and usefulness of this method have been confirmed through video recording of the process of sandbar deformation, observations of water level, and topographic surveying before and after the experiment.
