Coastal vulnerability of a pinned, soft-cliff coastline, II: assessing the influence of sea walls on future morphology
Coastal vulnerability of a pinned, soft-cliff coastline, II: assessing the influence of sea walls on future morphology
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DOI：
10.5194/esurf-2-233-2014
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发表时间：
2014-01-01
影响因子：
3.4
通讯作者：
Murray, A. B.
中科院分区：
文献类型：
--
作者：
Barkwith, A.;Hurst, M. D.;Murray, A. B.
长期以来，人们一直采用海岸防护措施来阻止或减缓海岸侵蚀，并通过实地研究和数值模拟详细研究了其对当地沉积物通量和生态的影响。修正的沉积物通量制度对中尺度侵蚀和增生的非局部影响受到的关注较少。由于防御结构造成的这种规模的形态变化可能难以量化或用实地数据识别。工程规模的数值模型通常用于评估现代防御措施对当地海岸侵蚀的设计，但往往不能覆盖大片海岸，也很少用于评估旧结构的影响。我们扩展了以前的工作，探讨海堤的演变和形态的敏感性钉，软悬崖，桑迪海岸线在不断变化的波浪气候的影响。以英国东约克郡的荷里活海岸为例，采用中尺度数值海岸演变模式，对观测到的波浪气候资料进行线性扰动，以评估海岸形态对波浪气候变化的敏感性。对模拟输出的比较分析表明，该区域南部的海堤对沉积物通量的影响较大，因为这部分海岸沿着的沉积物可用性增加。研究发现，多个防御结构，包括相隔数公里的防御结构，相互作用，在不断变化的波浪气候下造成沿海形态的复杂变化。虽然在空间和时间上的异质性，海堤一般减缓海岸后退和积累沉积物的向上漂移的一面。
Coastal defences have long been employed to halt or slow coastal erosion, and their impact on local sediment flux and ecology has been studied in detail through field research and numerical simulation. The non-local impact of a modified sediment flux regime on mesoscale erosion and accretion has received less attention. Morphological changes at this scale due to defending structures can be difficult to quantify or identify with field data. Engineering-scale numerical models, often applied to assess the design of modern defences on local coastal erosion, tend not to cover large stretches of coast and are rarely applied to assess the impact of older structures. We extend previous work to explore the influences of sea walls on the evolution and morphological sensitivity of a pinned, soft-cliff, sandy coastline under a changing wave climate. The Holderness coast of East Yorkshire, UK, is used as a case study to explore model scenarios where the coast is both defended with major sea walls and allowed to evolve naturally were there are no sea defences.Using a mesoscale numerical coastal evolution model, observed wave-climate data are perturbed linearly to assess the sensitivity of the coastal morphology to changing wave climate for both the defended and undefended scenarios. Comparative analysis of the simulated output suggests that sea walls in the south of the region have a greater impact on sediment flux due to increased sediment availability along this part of the coast. Multiple defence structures, including those separated by several kilometres, were found to interact with each other, producing complex changes in coastal morphology under a changing wave climate. Although spatially and temporally heterogeneous, sea walls generally slowed coastal recession and accumulated sediment on their up-drift side.