| Project/Area Number |
17580219
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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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 | National Agricultural Research Organization |
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Principal Investigator |
SHIONO Takahiro National Agricultural Research Organization, National Institute for Rural Engineering, Department of Land and Water Resources, Senior Researcher (30343982)
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| Co-Investigator(Kenkyū-buntansha) |
HARAGUCH Noburo National Agriculture and Food Research Organization, National Agricultural Research Center for Kyusyu Okinawa Region, Sustainable Soil Management Research Team, Chief Researcher (30370620)
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| Project Period (FY) |
2005 – 2007
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| Project Status |
Completed (Fiscal Year 2007)
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| Budget Amount *help |
¥2,750,000 (Direct Cost: ¥2,600,000、Indirect Cost: ¥150,000)
Fiscal Year 2007: ¥650,000 (Direct Cost: ¥500,000、Indirect Cost: ¥150,000)
Fiscal Year 2006: ¥700,000 (Direct Cost: ¥700,000)
Fiscal Year 2005: ¥1,400,000 (Direct Cost: ¥1,400,000)
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| Keywords | fine sediment / vegetation / sediment transport / deposition / reddish sediment runoff |
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| Research Abstract |
Reddish fine sediment runoff from agricultural fields results in coastal environmental problems in Okinawa, Japan. The sediment delivered to the coastal areas causes water pollution, sedimentation, and degrades the coastal ecosystems and fisheries resources. Vegetation reduces runoff of non-point-source pollutants from the fields into the streams. Then, utilization of vegetation in fallow fields contributes to the reddish sediment control. However, sufficient information has not been provided to determine the appropriate specifications in the field design. Therefore, the design requires a tool to evaluate vegetation performance under a variety of conditions. The objective of this study was to construct a numerical model simulating sediment transport in vegetation in a fallow field and evaluate the vegetation for the reduction of reddish sediment loads. Field plot experiments in Okinawa were shown the effectiveness for reddish sediment control with vegetation under natural conditions. Laboratory flume experiments demonstrated the sediment transport process in vegetation. A numerical model simulating sediment transport in vegetation was constructed to determine the vegetation efficiency. The model was verified using the data obtained by the field plot experiments. The sensitivity analysis of the model showed that the length of the vegetation (i.e. the dimension of the vegetation in the direction of flow) and unit flow discharge have a great effect on sediment removal efficiency. Model simulation indicated that the effective and efficient length of vegetation for a turf grass for the reduction of reddish sediment loads under typical farmland conditions in Okinawa.
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