Determination of mangrove forest performance in reducing tsunami run-up using physical models
Determination of mangrove forest performance in reducing tsunami run-up using physical models
复制标题
使用物理模型确定红树林在减少海啸爆发方面的表现
作者：
H. Ismail;A. K. Abd Wahab;N. Alias
热带海岸线边缘的红树林等沿海生态系统已被认为是沿海地区抵御海啸破坏性袭击的天然保护者。在本文中，作者旨在研究海啸波对典型红树林的相互作用，并确定其在减少上升方面的性能。使用带有红树林模型的水力水槽进行了实验室实验，其中使用 1:100 的比例，改变植被宽度 0、1、2 和 3 m，平均密度为每 100 cm2 8、6 和 4 棵树，进行测试。实验中考虑了 2.4 至 14 厘米之间的几个海啸波高的两种水位条件。实验中使用的溃坝方法产生了两种类型的波浪。在低水位条件下，钻孔形成，随后在高水位条件下产生孤立波。实验结果表明，一般来说，植被宽度和密度对海啸爆发具有抑制作用。研究发现，较大的植被宽度可以更有效地消散波浪能。红树林的前 1 m 宽度在高水位时会减少 23-32%，在低水位时会减少 31-36%。将红树林宽度增加到 2 和 3 m 可以进一步增加高水位时上升减少的平均百分比 39-50%，低水位时增加 34-41%。还观察到，红树林的密度对爬行减少的影响不如森林宽度那么显着。为了使红树林密度足以减少更多海啸的发生，需要提供每 100 平方米 4 棵树的额外密度。实验还表明，与树干和树冠相比，红树林根部在减少爬升方面更有效。这些实验成功地比较和展示了红树林在消散波浪能方面的有用性，所产生的结果有利于启动设计指南，以确定红树林地区开发项目的退缩限制或缓冲区。
Coastal ecosystems such as mangroves fringing tropical coastlines have been recognized as natural protectors of the coastal areas against destructive attack of a tsunami. In this paper, the authors aim to investigate the interaction of a tsunami wave on a typical mangrove forest and to determine its performance in reducing the run-up. A laboratory experiment using a hydraulic flume with a mangrove forest model was carried out in which tests were conducted by varying the vegetation widths of 0, 1, 2 and 3 m and average densities of 8, 6 and 4 trees per 100 cm2 using a scale ratio of 1:100. Two conditions of water levels were considered in the experiments at several tsunami wave heights between 2.4 and 14 cm. The dam break method used in the experiments produced two types of waves. At low water condition, a bore was developed and subsequently, a solitary wave was produced during high water. The results of the experiments showed that in general, vegetation widths and densities demonstrate a dampening effect on tsunami run-up. A larger vegetation width was found to be more effective in dissipating the wave energy. The first 1 m width of mangrove forest could reduce 23–32 % during high water and 31–36 % during low water. Increasing the mangrove forest width to 2 and 3 m could further increase the average percentage of run-up reduction by 39–50 % during high water and 34–41 % during low water condition. It was also observed that densities of the mangrove forest do not influence the run-up reduction as significantly as the forest widths. For mangrove forest densities to be significantly enough to reduce more tsunami run-up, an additional density of 4 trees/100 m2 needs to be provided. The experiments also showed that mangrove roots are more effective in reducing the run-up compared to the trunks and canopies. The experiments managed to compare and present the usefulness of mangrove forests in dissipating wave energy and results produced are beneficial for initiating design guidelines in determining setback limits or buffer zones for development projects in mangrove areas.