Japan Geoscience Union Meeting 2019

Presentation information

[E] Poster

M (Multidisciplinary and Interdisciplinary) » M-TT Technology & Techniques


Mon. May 27, 2019 5:15 PM - 6:30 PM Poster Hall (International Exhibition Hall8, Makuhari Messe)

convener:Yuichi S. Hayakawa(Faculty of Environmental Earth Science, Hokkaido University), Shigekazu Kusumoto(Graduate School of Science and Engineering for Research, University of Toyama), Christopher A Gomez(Kobe University Faculty of Maritime Sciences Volcanic Risk at Sea Research Group)

[MTT47-P01] High-definition topography monitoring after riverbed cultivation in the Echi River, central Japan

*Takuro Ogura1,2, Satoshi Asano3, Toshiaki Mizuno3, Yoshihiro Azuma3, Takeshi Kitai4, Yuichi S Hayakawa5,6, Kotaro Iizuka6 (1.Graduate School of Frontier Sciences, The University of Tokyo, 2.Graduate School of Environmental Science, Hokkaido University, 3.Lake Biwa Environmental Research Institute , 4.Lake Biwa Museum, 5.Faculty of Environmental Earth Science, Hokkaido University, 6.Center for Spatial information Science, The University of Tokyo)

Keywords:High-definition topographic data, riverbed cultivation, UAV, SfM-MVS photogrammetry, Echi river

Natural processes of erosion and deposition on riverbeds are generally limited in Japan due to large-scale public constructions including dams and banks. As a result of the construction of dams, sediment transport may dramatically decrease in the downstream area are, and the river ecosystem can also be affected. To make sediment move more vigorously, we cultivated the armored gravel riverbed with heavy machinery. We then explore the effects of riverbed cultivating by monitoring the topographic changes with high-frequency and high-definition measurements (HF-HD measurements), whereas conventional measurement technologies do not compensate spatial resolution and temporal resolution to capture the topographic change. Using UAS (Unmanned Aerial Vehicle) and SfM-MVS (Structure-from-Motion – Multi-view Stereo) photogrammetry, we found the transportation of the fixed gravels were occurring after cultivating the riverbed in 2017. The temporal and spatial resolutions of the HF-HD topographic data was approximately 2 months and 10 cm, respectively. In July 2018, water flow at 130 m3/s was discharged from the upstream dam, and we confirmed that a part of the gravels in the cultivated area was eroded and replaced with new sediments (Fig. 1). These observations indicate that riverbed monitoring using UAV and SfM - MVS can be a practical tool for proper management of riverbeds. Applying this result, we will further clarify the relationships between the water quantity discharged from the dam and the riverbed topographic changes.