[H-TT14] 高精細地形情報と人新世におけるコネクティビティ

[HTT14-03] Analysis of sediment deposition using RTK-UAV: A case study of Echi River, central Japan

*小倉 拓郎¹、水野 敏明²、山中 大輔³、早川 裕弌⁴ (1.筑波大学生命環境系、2.滋賀県琵琶湖環境科学研究センター、3.滋賀県立琵琶湖博物館、4.北海道大学地球環境科学研究院)

キーワード：RTK-UAV、土砂堆積量、DSM、愛知川

Public works using three-dimensional (3D) data has been carried out in various institution. UAVs have been widely spread and utilized to acquire 3D data. However, it is necessary to ensure 3D accuracy when conducting UAV measurements. It is also required to spend a lot of work time and cost using GCPs (Ground Control Points). Here we show that UAV equipped with RTK-GNSS to calculate the amount of sediment deposition in two periods. The study area is 10 km from the mouth of the Echi River in Shiga Prefecture. We took photos using RTK-UAV in July 2021 and September 2021. We also created DSMs and ortho-images from the images using Agisoft Metashape Professional. The accuracy of DSMs was about 1 cm. Heavy rainfall occurred between July 2021 and September 2021, which increased the dam's water release upstream. As a result, the water release rate of about 1300 m³/s lasted for about 6 hours, and sediment deposition was observed. Therefore, the amount of sediment deposited could be calculated with high accuracy for sedimentation areas with shallow water depths. Therefore, the amount of sediment can be quickly measured in a small river with high precision.