Long-Term, Large-Scale Morphodynamic Effects of Artificial Dune Construction along a Barrier Island Coastline
Long-Term, Large-Scale Morphodynamic Effects of Artificial Dune Construction along a Barrier Island Coastline
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障壁岛海岸线人工沙丘建设的长期、大规模形态动力效应
DOI：
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发表时间：
2011
期刊：
影响因子：
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通讯作者：
A. Murray
中科院分区：
文献类型：
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作者：
N. Magliocca;D. McNamara;A. Murray
由于景观形成过程对人类的影响，而人类对景观形成过程的操纵越来越大，因此人类活动与景观过程之间的相互作用可以形成一个动态耦合系统。尽管沙障岛具有动态的性质，但经济激励和娱乐机会吸引着人类和发展。形成堰洲岛的风暴驱动的沉积物运输事件对人类和基础设施构成危害，旨在预防或减轻此类事件的操作将人类行为与长期岛屿形态动力学联系起来。为了探索自然屏障岛的行为与人类作为动力系统组成部分的行为有何不同，我们使用了风暴驱动的滨面/岛屿/后屏障系统内沉积物重新分布和人类在陆上屏障岛内沉积物重新排列的数值模型。在模拟的自然系统中，由风暴活动的随机间歇引发的沙丘生长和岛屿稳定期与暴风雨期交替进行，在暴风雨期，海岸线侵蚀和频繁的冲过调节了沙丘的高度。当模型中包括人类时，冲积物就会从岛上移走，人工建造的高沙丘就会重建。这些操作倾向于过滤适度的过度事件。然而，随着海岸线的侵蚀和海平面的上升，这些操纵在长期内促进了较低和较窄的岛屿，因此当沙丘被覆盖时，沉积物的再分布更为严重。因此，耦合的人类/屏障系统在岛屿稳定性增加和岛屿突然位移之间表现出更大的波动。增加人工维持的沙丘的高度会增加岛屿缩小的速度，从而增加基础设施的迁移，并增加从系统外进口泥沙的需要。
Abstract Interactions between human manipulations and landscape processes can form a dynamically coupled system because landscape-forming processes affect humans, and humans increasingly manipulate landscape-forming processes. Despite the dynamic nature of sandy barrier islands, economic incentive and recreational opportunities attract humans and development. Storm-driven sediment-transport events that build barrier islands constitute hazards to humans and infrastructure, and manipulations aimed at preventing or mitigating such events link human actions and long-term island morphodynamics. To explore how the behavior of a natural barrier island differs from one in which humans are dynamic system constituents, we use a numerical model of storm-driven sediment redistributions within the shoreface/island/back-barrier system and human rearrangements of sediment within the subaerial barrier island. In a modeled natural system, periods of dune growth and island stability, initiated by stochastic lulls in storm activity, alternate with stormy periods, in which shoreline erosion and frequent overwash regulate dune heights. When humans are included in the model, overwash deposits are removed from the island, and artificially high dunes are rebuilt. These manipulations tend to filter moderate overwash events. However, with shoreline erosion and rising sea level, these manipulations promote lower and narrower islands in the long term, so that when dunes are overtopped, the sediment redistributions are more severe. Thus, the coupled human/barrier system exhibits wider swings between increased island stability and sudden island displacements. Increasing the height of artificially maintained dunes increases the rate of island narrowing and, therefore, infrastructure relocation, and increases the need for sediment to be imported from outside the system.