[H-TT14] HIGH-DEFINITION TOPOGRAPHIC SURFACE DATA FOR CONNECTIVITY IN THE ANTHROPOCENE

[HTT14-P03] Reconstruction of traditional knowledge of flood damage by integrating high-definition topographic data and local knowledge

*Takuro Ogura¹, Kazuyuki Shimamoto², Toshiaki Mizuno³, Hiroyuki Yamauchi⁴, Daisuke Katayama², Tsuyoshi Hattanji⁵ (1.Graduate School of Education, Hyogo University of Teacher Education, 2.Lake Biwa Museum, 3.Lake Biwa Environmental Research Institute, 4.Art Research Center, Ritsumeikan University, 5.Faculty of Life and Environmental Sciences, University of Tsukuba)

Keywords:Eco-DRR, UAV-LiDAR, traditional knowledge of flooding

Landslides and floods, frequently occurring in Japan due to torrential rains in its humid fluctuation zone, raise concerns about exacerbated disasters amid climate change—traditional Eco-DRR facilities, like levees and flood-protection forests, historically safeguarded against floods by leveraging the ecosystem. However, loss, modification, and urbanization have obscured their existence and distribution. This study re-evaluates forgotten Eco-DRR facilities in the Echi River basin, Shiga Prefecture, employing high-definition topographic data, historical documents, and resident interviews. The Study area is the riparian forest 15.2 km from the Echi River mouth in Higashi-omi City, where residents recall an old stone dam named "Saruo" in the forest's southeastern part. Utilizing UAV-LiDAR technology, we measured the forest floor, generated point cloud data, and extracted ground surfaces using filtering software. Resident reports of Saruo in farmland south of the forest guided the mapping of convex landforms Saruo by merging topographic data in GIS. Comparison with historical maps, such as the 1874 Kanzaki-gun village map, facilitated the identification and scale determination of Saruo. Topographic interpretation unveiled six convex landforms, three confirmed as Saruo stone dams. Discrepancies between observed sizes and historical records suggest modifications over time, including modern embankment construction post-1874. These findings may result from sedimentation or land modifications, indicating new Saruo's presence and existing ones' discrepancies. Future efforts aim to integrate natural and human data to understand disaster risk comprehensively.