Author(s): Takahiro Itoh, Takahisa Mizuyama, Satoshi Tagata
Linked Author(s): Takahiro Itoh
Keywords: Debris flow monitoring, loadcell, Debris Flow measurement system with Loadcell and Pressure sensor system (dflp), sediment concentration, specific weight.
Abstract: In debris flow monitoring in Sakurajima Island in Japan, temporal changes of flow depth, discharge and bed profiles have been tried to be collected using ultrasonic sensors and video camera, and profiles of bed elevations are also monitored along the channel for longitudinal deposition and near river mouth in the sea using a sounding machine to evaluate sediment runoff volume from river mouth. However, it was quite difficult to obtain continuous data for sediment discharge and the runoff volume due to debris flows. Debris flows are observed by the newly installed debris flow measurement system with loadcell and pressure sensor (DFLP), and sediment concentration of both coarse sediment phase and suspended & liquid phase can be calculated using data measured by the DFLP (Osaka et al. , 2014). In Arimura River, debris flow took place 13 times in 2014, and debris flows have been observed on June 27th, July 30th, August 29th and November 1st, and debris flows on June 27th are obtained by DFLP systems. While, in Nojiri River, debris flow took place 17 times in 2014, and debris flows have been observed on May 14th, June 21st, June 27th, July 9th, August 1st and November 1st. Debris flows on June 21st and 27th are measured by three DFLP systems in Nojiri River. In present study, temporal changes of specific weight, sediment concentration and sediment volume of debris flow are newly calculated using data obtained by DFLP systems in Nojiri and Arimura Rivers in 2014. Sediment concentration and specific weight are calculated such as 0. 552 (left side), 0. 667 (center), 0. 816 (right side) and 1. 94 (left side), 2. 13 (center), 2. 38 (right side), respectively, in Nojiri River (June 27th, 2014). In Arimura River, sediment concentration and specific weight are calculated as 0. 463 and 1. 76, respectively, on June 27th, 2014
Year: 2017