2021 Fiscal Year Final Research Report
Elucidation of the mechanism of alternating mainstream change at the bifurcated channel in alluvial fan rivers and its development of countermeasures
| Project/Area Number |
19H02243
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| Research Category |
Grant-in-Aid for Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Review Section |
Basic Section 22040:Hydroengineering-related
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| Research Institution | Kitami Institute of Technology |
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Principal Investigator |
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| Co-Investigator(Kenkyū-buntansha) |
竹林 洋史 京都大学, 防災研究所, 准教授 (70325249)
川村 里実 (山口里実) 国立研究開発法人土木研究所, 土木研究所(寒地土木研究所), 主任研究員 (70399583)
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| Project Period (FY) |
2019-04-01 – 2022-03-31
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| Keywords | 扇状地河川 / 谷底平野 / 河道変動 / 流路変動 / 突発災害 / 交番現象 |
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| Outline of Final Research Achievements |
Sediment supply due to debris flow, etc. causes severe flow path fluctuations due to sedimentation in the downstream river channel, but the effect is greatly affected by the flow pattern of the debris flow.
The flow path alternating mainstream changephenomenon, which is the main cause of flow path fluctuations in alluvial fan rivers, tends to become more active as the flow rate increases, but there are cases where it cannot be said unconditionally depending on the braided channel shape.
In addition, although the alternating mainstream change is greatly affected by vegetation on flood plain, the branching characteristics of the flow path that develops differ greatly depending on the characteristics of whether or not it is easily flowded of the vegetation.
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| Free Research Field |
土砂水理学
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| Academic Significance and Societal Importance of the Research Achievements |
出水時に突発的に生じる扇状地河川の河道の移動は，山地区間からの一時的な大量の土砂供給等や植生の流出のしやすさや分岐部の形状を取り込む必要があり，これまで現象が解明されてきた中下流域の現象とは明らかにそのメカニズムが異なっていることが明らかとなり，扇状地河川における河道計画・維持手法についての着目点が明確にされた．
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