EXAMINATION OF THE DISASTER PROCESS OF RIVER MANAGEMENT FACILITIES AND A RAILWAY BRIGE IN THE KAGETSU RIVER AT KYUSHU-HOKUBU HEAVY RAIN IN 2017

Abstract

 The disaster process of river management facilities and a railway bridge in the Kagetsu river at Kyushu-hokubu heavy rain in 2017 was examined through the a field survey and numerical simulation of flood flows. The discharge hydrograph at the Kagetsu water level observation station was obtained by a two-dimensional flood flow analysis using water level hydrographs as boundary conditions. The maximum and time integrated velocity, friction velocity were obtained by distributed hydrological model for rain-fall runoffs in watershed and 2D unsteady free-surface flow analysis. Through these results, disaster process of river management facilities and a railway bridg were examined.