Elucidation of the behavior and feasible control of floodwater-derived materials to support evacuation and recovery inevent of flood damage

2023 Fiscal Year Final Research Report

• Project/Area Number: 19K04968
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Review Section: Basic Section 25030:Disaster prevention engineering-related
• Research Institution: Shimane University
• Principal Investigator: Sato Hirokazu 島根大学, 学術研究院環境システム科学系, 助教 (90609364)
• Project Period (FY): 2019-04-01 – 2024-03-31
• Keywords: 洪水氾濫 / 水害 / 氾濫土砂 / 氾濫流木 / 氾濫土砂の制御

Outline of Final Research Achievements

The conditions of flood inundation substances and topography/geological features in a real river were investigated to determine the scale and hydraulic conditions of the hydraulic model experiments, and to understand the behavior of driftwood and sediment in the inner area of the levee during flood inundation. It was confirmed that the amount of driftwood and sediment inundation also depends on crossing structures such as bridges on the river channel side. The amount of sediment inundation from the levee increased as the size of the levee breach increased, and the sediment distribution in the inundation area was more upstream of the center of the levee mouth, regardless of the hydraulic conditions. The amount of sediment inundated by the levee due to the break was reduced by installing piles and boards near the back of the embankment on the inner side of the levee, based on methods and techniques that can be implemented by residents near the river for flood control activities.

Free Research Field

河川工学

Academic Significance and Societal Importance of the Research Achievements

河川周辺の地域住民が水防活動で実施可能な技術・工法でも破堤規模を緩和し、堤内地への土砂氾濫を抑制できる可能性を示した意義は大きい。これにより水害時に氾濫水が引いた後の氾濫土砂の処理に費やす時間の短縮に貢献できる。また、このような工夫により洪水氾濫とともに堤内地へ流入する流木やゴミの量も、堤防付近で一定量捕捉されて減じられることが期待される。このような氾濫物質の抑制は、洪水氾濫中の避難が余儀なくされた状況において、避難中の安全性の向上に寄与できる可能性も示唆している。