2023 Fiscal Year Annual Research Report
Analysis of morphodynamic evolution in a meandering estuarine channel in the context of climate change
| Project/Area Number |
20K14840
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| Research Institution | Tokyo Metropolitan University |
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Principal Investigator |
Azhikodan Gubash 東京都立大学, 都市環境科学研究科, 助教 (50821740)
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| Project Period (FY) |
2020-04-01 – 2024-03-31
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| Keywords | Morphological changes / Chikugo River estuary / long-term / tidal forcing / flood disaster / erosion / sediment transport / deposition |
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| Outline of Annual Research Achievements |
On a seasonal timescale, the estuarine morphology showed a deposition trend driven by the tide-induced net upward sediment transport during the dry season and an erosion trend driven by the flood discharge-induced downward sediment transport during the rainy season. However, the estuarine channel morphology showed a decreasing trend (erosion of 1-1.5 m) for a long-term period (more than 10 years). This means that the increased flood discharge eroded not only the surface silt and clay layer but also the bottom sand layer in the estuarine channel. This resulted in a drastic decrease in the bed elevation of the estuarine channel that could not be fully recovered by the tide-induced net upward sediment transport during the dry season. Currently, we are trying to find the best model for predicting the morphological changes of the estuarine channel using the measured data of water level (downstream), discharge (upstream), bed geometry, sediment characteristics, sediment volume, etc.
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