METHOD TO ESTIMATE LANDSLIDE AND THEIR RUNOUT DURING HEAVY RAINFALL

Abstract

 This study proposes a numerical simulation model to integrate prediction for the occurrence of landslides, runout process of soil blocks released by landslides, and erosion-deposition process of the sediment in a channel network. The simulation model was applied to the upper reaches of Souzugawa river in Hiroshima prefecture during heavy rainfall in July 2018, to investigate landslides and their runout process. The simulated result shows that immediately after the occurrence of landslides, the sediment deposition takes place in 2nd order to 4th order channels, and after the end of rainfall, the deposition takes place in the 4th order channel. The result indicates that sediment produced by the landslides is stored in the channel network and after that runout with the flood.