Development of numerical methods for estimating spatiotemporal changes of discharge, roughness coefficient, bed level using observed water levels

2018 Fiscal Year Final Research Report

• Project/Area Number: 16K06515
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Research Field: Hydraulic engineering
• Research Institution: Kyushu Institute of Technology
• Principal Investigator: SHIGE-EDA MIREI 九州工業大学, 大学院工学研究院, 准教授 (70380730)
• Project Period (FY): 2016-04-01 – 2019-03-31
• Keywords: 水面形 / 時空間変化 / 流量 / 粗度係数 / 河床位 / 推定法 / 流束差分離法

Outline of Final Research Achievements

In this study, to acquire information that contributes to river management, estimation methods of spatiotemporal change of flow discharge, roughness coefficient and bed level in river channel using a temporal change of observed water level were developed. Two estimation methods, estimation methods I and II, were developed. Estimation method I could estimate spatiotemporal changes of flow discharge, water level and bed level using the water level hydrograph as boundary conditions. Estimation method II could estimate spatiotemporal changes of flow discharge, roughness coefficient and bed level using the temporal change of water surface profile. The estimation methods were verified against the experimental results and flood data in the river. It showed that the estimation method I and II could reproduce the experimental results and flood data in the river such as the flow discharge hydrograph, peak discharge and low channel roughness coefficient with reasonable accuracy.

Free Research Field

数値流体力学

Academic Significance and Societal Importance of the Research Achievements

本研究の学術的な意義は，高い精度で測定できる水面形の経時変化から，洪水時の流量，粗度係数，河床高の時空間変化を精度良くかつ効率よく求めることができる推定法を，世界に先駆けて開発した点にある．この推定法の開発は，洪水時の水位，流量，粗度係数の時空間変化を総合的に把握し，これらの変化と河道の平面形状や縦・横断変化，樹木繁茂状況などの河道特性とを結びつけることで，変化の原因を特定することにつながる．つまり，本研究の社会的意義は，今後本格的に始まる計画的な河道管理の具体を検討する上で有用な情報を提供できる点にある．