Automated real-time stream-velocity/streamflow acquisition using fluvial acoustic tomography

2019 Fiscal Year Final Research Report

• Project/Area Number: 17H03313
• Research Category: Grant-in-Aid for Scientific Research (B)
• Allocation Type: Single-year Grants
• Section: 一般
• Research Field: Hydraulic engineering
• Research Institution: Hiroshima University
• Principal Investigator: Kawanisi Kiyosi 広島大学, 工学研究科, 准教授 (40144878)
• Project Period (FY): 2017-04-01 – 2020-03-31
• Keywords: 河川流量 / 洪水 / 水資源 / 水循環 / 音響トモグラフィー

Outline of Final Research Achievements

This study demonstrates the improved fluvial acoustic tomography system (FATS), a promising approach for automatically measuring streamflows with high temporal resolution for a long period. Unlike past hydro-acoustic systems, the FATS enables us to continuously capture the depth- and range-averaged water velocity with a single transducer set. Streamflow measurements were performed in a gravel-bed river (depth: 0.8 m under low-flow conditions, width: 115 m). The average stream velocities and streamflows are automatically estimated from the acoustic data and water level data. The real-time flow data can be monitored by the Internet access. The continuous FATS estimates indicate that the streamflow does not change smoothly with the river stage. Analyses reveal that the streamflow may not be estimated accurately from a smooth rating curve (RC). The FATS captures short-wave irregularities in the streamflow time-series. It is observed that the rapid changes of RC occur owing to flood events.

Free Research Field

水工学

Academic Significance and Societal Importance of the Research Achievements

近年顕著になりつつある地球規模の気候変動によって，洪水や干ばつが頻発する恐れが危惧されている中で，河川流量観測法の高度化はまさに喫緊の課題である。河川音響トモグラフィー法を用いて河川流量観測を自動化し、リアルタイムに正確な流量を常時監視を可能にする本研究は、少子高齢化による調査員の不足や安全確保の問題を解決し、洪水被害の軽減や適切な河川環境の保全に役立つ。本研究は、大規模な気候変動にともなう水循環の変化を把握する上でも重要な役割を担うと考えられ、水工学分野に大きく貢献し、人類規模の有用な社会的貢献を果たすものである。