2019 Fiscal Year Annual Research Report
気候変動と土地利用変化を考慮したダム開発の河川水文や地形への影響評価
| Project/Area Number |
18F18049
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| Research Institution | Tokyo Institute of Technology |
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Principal Investigator |
鼎 信次郎 東京工業大学, 環境・社会理工学院, 教授 (20313108)
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| Co-Investigator(Kenkyū-buntansha) |
SANYAL JOY 東京工業大学, 環境・社会理工学院, 外国人特別研究員
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| Project Period (FY) |
2018-07-25 – 2021-03-31
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| Keywords | dam-related erosion / sediment yield / river erosion / climate change |
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| Outline of Annual Research Achievements |
Changes in climatic factors such as rising rainfall intensity may increase soil erosion and the frequency of sediment transporting high flow events, while removal of forest cover could lead to greater soil erodibily. Both factors can affect the erosion/deposition rates of rivers. Dams are known to cause channel degradation downstream by trapping the sediment supply from upstream areas. We argue that the changes in flow patterns, sediment loads and downstream bed degradation, generally attributed to damming of rivers, could also have been happening independent of the dams due to large scale land use and climate changes. Hence, we intend to assess the degree of influence the dams would exert vis-avis possible climate and land use changes in the geomorphic adjustment of channels. In this fiscal year, those following items were carried out. 1) SWAT Model final calibration and validation with sensitivity analysis for dams. 2) Creating scenarios a) with and without the dams in the model, b) land use changes and c) future climatic conditions and analyse the outputs.3) Documenting the comparative analysis of channel erosion due to land cover change and dam construction. 4) Documenting the results of the experiment related to the expected dam-related downstream erosion under different degree of climate and land cover changes in the upstream catchment. 5) Present a paper at international conferences, 6) Writing manuscripts and submitted to journals. Those were successfully carried out. In addition, a new physical experiment on sediment transport was set up.
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| Current Status of Research Progress |
Current Status of Research Progress
2: Research has progressed on the whole more than it was originally planned.
Reason
1) SWAT Model calibration and validation, 2) Creating scenarios with and without the dams in the model, land use changes and future climatic conditions and analyse the outputs, 3) Documenting the comparative analysis of channel erosion due to land cover, 4) Documenting the results of the experiment related to the expected dam-related downstream erosion, 5) Conference presentations, and 6) Journal paper writing were all well carried out.
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| Strategy for Future Research Activity |
Writing papers and the project completion report will be the first objective of the final fiscal year. The first part of the research deals with predicting dam-related downstream geomorphic response with widely available stream gauge data on the Godavari River Basin, India. It has been accepted for publication in Singapore Journal of Tropical Geography, and the final proof reading will be necessary. The second part of the research is under review in another international journal and it is related to the downstream geomorphic impact of a large dam under climate change. The revision will soon be necessary. The third and final portion is under preparation as a manuscript on the comparative effect of dam building and climate change on dam-induced erosion. A significant portion of the remaining time will be invested on writing this manuscript. In addition to the abovementioned plan, some physical experiments with a stream table will be carried out and preliminary data will be gathered in terms of digital elevation models of the experimental channel before and after dam creation.
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Research Products
(2 results)
