INUNDATION ANALYSIS DUE TO DIKE BREAK OF THE CHIKUMA RIVER CONSIDERING DRAINAGE PROCESS AND HOUSE DAMAGE

Abstract

 A disaster caused by heavy rain and storms occurred due to the effect of Typhoon No. 19 in October 2019. In Nagano City, large scale inundation damage was caused by overflow and dike break from the left bank of the Chikuma River. In this study, the inundation analysis model was developed to examine the inundation water behavior. The obtained inundation water depth was good agreement with the observed inundation water depth. Therefore, the validity of the analytical model was shown. In addition, the feature of drainage was shown from the analysis results considering drainage process. However, sewerage system, waterway and drainage by pump trucks were not taken into consideration in this analysis model, and future issues regarding model improvement were also shown. In addition, the analysis model with 2m grid was developed on the dike break site, and the inundation water flow on the road and the fluid force around the house were obtained. From these results, the state of hydraulics on the dike break site was shown in detail.