THE EFFECT OF THE LEVEE MATERIALS AND RIVERBED TO PROCESS OF RIVER LEVEE BREACH

In recent years, local heavy rainfall has increased due to the extreme weather in Japan, causing enormous inundation damage in various places. The river levee breach is one of the disasters that causes enormous inundation damage, and a typical example is Typhoon No. 19 that occurred in October 2019. It can be said that elucidation of the levee breach mechanism is important for disaster prevention and mitigation in the midst of frequent damage. The authors have conducted fundamental experiments in which water is stored in river space and experiments that reproduce river flow, targeting simulated embankments composed of clay, sand, and gravel. We have examined the effects on river flow. In this study, we are conducting experiments under different conditions of levee material and riverbed width, and by adding new measurement items such as streamlines and overflow rates, we are investigating a more detailed overflow breach process.