2015年関東・東北豪雨における鬼怒川氾濫による常総市の洪水氾濫状況

抄録

A significantly severe flood disaster in the Kinugawa basin was occurred due to an unprecedented rainfall on Sep. 10, 2015. A bank failure and overflows at several points along the Kinu River occurred and inundated around 40km² area of the flood plain in Joso city, Ibaraki Pref., particularly Mitsukaido district. In this study, we applied 1D-2D coupled hydrodynamic model to simulate the flood and to evaluate the effects of a drainage canal called Hachikenbori gawa located on the center of the flood plain for the inundations. As a result, we found that the flood overtopped and flowed into the canal and it caused earlier inundations in the downstream Mitsukaido area along the canal than the main flood.