1996 Fiscal Year Final Research Report Summary
On the hydraulic and environmental functions of flood defense woods.
| Project/Area Number |
07455197
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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 |
水工水理学
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| Research Institution | HIROSHIMA UNIVERSITY |
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Principal Investigator |
FUKUOKA Shoji Faculty of Engineering, HIROSHIMA UNIVERSITY Professor, 工学部, 教授 (30016472)
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| Co-Investigator(Kenkyū-buntansha) |
O-GUSHI Hiroya Faculty of Engineering, HIROSHIMA UNIVERSITY Research Associate, 工学部, 助手 (10274119)
HIBINO Tadashi Faculty of Engineering, HIROSHIMA UNIVERSITY Research Associate, 工学部, 助手 (50263736)
KAWANISHI Noboru Faculty of Engineering, HIROSHIMA UNIVERSITY Associate Professor, 工学部, 助教授 (40144878)
WATANABE Akihide Faculty of Engineering, HIROSHIMA UNIVERSITY Associate Professor, 工学部, 助教授 (00240474)
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| Project Period (FY) |
1995 – 1996
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| Keywords | flood defense woods / meandering / phase sift / groin / cut / flood control / flood channel / main channel |
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| Research Abstract |
The flood defense woods were planted and has been preserved because the house and the field along the riverside are defended from the flood damage. Recently, because the tree clusters in the river channel cause the resistance of flows, The flood defense woods was deforested for the flood control. To maintain an excellent river environment, the effect on the leaving method and the flood control of the woods was examined. The effect of the trees changes depending on the arrangement of the tree clusters to the shape of the river channel, depth on the flood channel, and the velocity of the flow in the main channel. The bed topography of river changes due to the flow which is influenced by flood defense woods. A plane structure of the flow between a flood channel and the main channel was clarified in this research. The exchange of the current is caused between the flood channel and the main channel in a compound meandering channel. In addition, flood flow are controlled by the flood control woods along river bank. A numerical model by which such flow fields were able to be explained enough was developed. It was shown to be able to analyze the flow of the compound meandering channel seen in the actual river by using this model. If the flood defense woods are deforested, high velocity is caused in that part. As a result, it has been understood that the flood control woods around damaged part may be lost due to flow if the part where were damaged is covered by a bank protection made of blocks. On the other hand, when a part of the flood defense woods was deforested, the flow velocity of the rive bank neighborhood is decreased and the secondary current in the outer bank are weaken. It is shown that there is a necessity for evaluating the value of the flood defense woods overall including such an effect of the flood control in the future.
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