2019年長野県千曲川洪水氾濫を対象とした家屋被害の調査報告と水害調査ガイドライン(案)の改善の提案

抄録

A heavy rainfall caused by Typhoon No. 19 resulted in flood inundation at the Chikuma River in Nagano Prefecture Japan on October 13, 2019. In particular, severe flood inundation damages at Hoyasu district along the Chikuma river were observed. In this paper, building damages in the district were focused and reported based on an on-site field survey conducted by the authors.

From the on-site survey results, it was found that highly damaged houses were observed along the two flow pathways in the inundation areas because of the local bathymetry and land surface roughness. Also, highly damaged houses were found around 350 m from the bank failure point. Finally, we proposed the middle-ranked damage classification in the guidelines for field survey of river flood disasters to improve the building damage survey results.