2011 Fiscal Year Final Research Report
Conservation and Restoration of Aquatic Plants with Bed Erosion in Brackish Water Zone
| Project/Area Number |
21560548
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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 |
Hydraulic engineering
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| Research Institution | 防衛大学校 |
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Principal Investigator |
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| Co-Investigator(Kenkyū-buntansha) |
KUNII Hidenobu 島根大学, 汽水域研究センタ-, 教授 (70161651)
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| Project Period (FY) |
2009 – 2011
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| Keywords | 水辺植生 / 基盤洗掘 / 保全 / 修復 |
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| Research Abstract |
The effect of wave action on the establishment of Zostera japonica, a brackish submerged macrophyte growing mainly in coastal areas, is discussed. The wave forces acting on Z. japonica were measured by using a small two components load cell installed under the bed of wave flume. The wave forces were too small to pull out Z. japonica shoot from bottom sediment. Sediment transport and bed form development under waves were also observed, and Z. japonica shoot was pulled out from the sand bed of flume when large ripples appeared on the sand bed in wave flume.
Laboratory experiments were performed to study wave transmission and wave reflection capacity of mangroves and trees as coastal protection from waves. Drag forces on a live pine in small scale open channel flow were measured by using a load cell. Drag forces on a circular cylinder in rapid flow were also measured. A theoretical analysis based on application of the continuity and energy equations to flow through the rows of trees were made to evaluate wave transmission and wave reflection capacity of mangroves and trees in coastal area. The significant wave reflection from mangroves with large and dense canopy was estimated.
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