Author(s): Masakazu Hashimoto; Ken Ichikawa; Kaori Amaya; Andre Araujo Fortes; Shosuke Sato

Linked Author(s): Masakazu Hashimoto, Ken Ichikawa, Andre Araujo Fortes

Keywords: Small and Medium Sized Rivers; River Management; Riparian Population

Abstract: We examined the characteristics of spatial distribution of riparian population and buildings along with the medium and small sized rivers in Tohoku Region, Japan. Recently, the number of cases that have damage near the medium and small sized river is increasing in Japan. Furthermore, the victims tend to be elder people who failed to evacuate in the early stage. To reduce the risk of that areas, appropriate observation and inspection need to be done with high-efficient and low-cost method such as UAV-SfM observations. For the high-efficient observations, levels of preference are better to be set with the information of riparian population and buildings. Thus, the objective of this study is to reveal the spatial distribution of riparian population and buildings quantitatively at medium and small sized river in Tohoku Region, Japan. We used data for the spatial distribution of population with the information of number of people aged 65 years old and 75 years old, and location of rivers as well. In this study we defined that riparian population is in the range of 250m which could cover the area damaged by the passed sever flood disasters near medium and small rivers. As a result, we revealed that the average residential ratio of medium and small sized river is about 60 % in Tohoku Region and the ratio was lower than the other area such as Kanto Region and Kyushu Region. For the further analysis, we plan to reveal the spatial distribution of the people older than 65 years old and the vulnerable area with elder people will to be identified.

DOI: https://doi.org/10.3850/IAHR-39WC2521711920221843

Year: 2022