2002 Fiscal Year Final Research Report Summary
Effective water management and control for a large scale irrigation/drainage system
| Project/Area Number |
11460110
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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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| Research Field |
Irrigation, drainage and rural engineering/Rural planning
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| Research Institution | Tokyo University of Agriculture and Technology |
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Principal Investigator |
KUBO Naritaka Tokyo University of Agriculture and Technology, Faculty of Agriculture, Associate Professor, 農学部, 助教授 (40134506)
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| Co-Investigator(Kenkyū-buntansha) |
OSATO Kouji Tokyo University of Agriculture and Technology, Faculty of Agriculture, Assistant, 農学部, 助手 (80143634)
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| Project Period (FY) |
1999 – 2002
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| Keywords | Irrigation and drainage / Water use efficiency / Water management / Unsteady flow / Numerical simulation / Implicit finite difference method |
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| Research Abstract |
Through four years study by the grant-in-Aid for Scientific Research following results are obtained. (1) About the user-friendly unsteady flow model, we can develop a model based on the implicit finite difference method. We applied the unsteady flow model to the drainage analysis for the Red river Delta in Vietnam, and we can show the effectiveness of the model. We also show that the model can be used as the Tank model for the runoff analysis by combining several interior boundary conditions. (2) About the drainage analysis in a large low-flat area, we selected a floating rice area in the Chao Phraya River Delta in Thailand as the study field. Through the water budget analysis, we examined the retarding capacity of the floating rice area. As the result, we proposed a project to build retarding area by surrounding dykes and to construct regulating reservoirs, and we also showed that the project could solve to some extent two difficult problems of flood during rainy season and drought du
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ring dry season. (3) About the abnormal tidal fluctuation by a construction of a tidal weir in a tidal river, we can solve the phenomena theoretically considering non-linearity of the friction term in the movement equation. As the result, we could show an formula that can calculate approximate amplitude of abnormal fluctuation with regard to the distance from the river mouth. (4) About the flow rate estimation in an irrigation canal by observing water levels, we develop a procedure by use of an unsteady flow model and optimization method. We applied that procedure to the field experiment using Murataka irrigation canal and also to the laboratory experiment by constructing a small-sized model canal. As the result, we verified that the procedure is very effective to estimate flow rate. However, we identified a new problem of treating friction term in case of the very small-scale reduced model experiment. This problem was not solved in this study but should be analyzed in the next step. (5) About the analysis of transient process from one steady state to the other one in an irrigation canal system when hydraulic facilities are controlled, we could solve some phenomena theoretically in some specific conditions. According to the solution, canals can be classified to short and long canals by a representative length obtained through non-dimensional analysis. As the results, we could show that the mechanisms of transient processes are quite different between short and long canals. Namely, in the case of the short canals, the unsteadiness is weakened by waves that go and return, and in the case of the long canals the unsteadiness is weakened by diffusion. Less
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