Morpho-sedimentary dynamics of a micro-tidal mixed sand and gravel beach, Playa Granada, southern Spain
Morpho-sedimentary dynamics of a micro-tidal mixed sand and gravel beach, Playa Granada, southern Spain
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DOI：
10.1016/j.margeo.2016.05.003
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发表时间：
2016-09
期刊：
影响因子：
2.9
通讯作者：
R. Bergillos;M. Ortega-Sánchez;G. Masselink;M. Losada
中科院分区：
文献类型：
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作者：
R. Bergillos;M. Ortega-Sánchez;G. Masselink;M. Losada
本文讨论了在形态和沉积学的变化的一个小潮混合砂和砾石海滩（普拉亚格拉纳达，西班牙南部）迫使波和水位的变化，和人类干预，通过营养。在为期一年的时间里，每月进行一次和风暴事件驱动的海滩调查，包括在两个选定地区进行地形测量和沉积物取样。确定了上海滩剖面的三种主要沉积物组分（砂、细砾石和粗砾石）和两种端元形态状态（凸形多护堤和凹形单风暴护堤）。在它们之间，形成了几个过渡剖面，其特点是逐渐重叠的护堤不断发展，在整个海滩剖面和深度上都产生了沉积物变异性。结果表明，在一个事件中达到的总助跑（包括水位）比波高更准确地区分侵蚀和沉积条件。他们还认为，混合砂和砾石海滩比桑迪海滩更快地从风暴侵蚀中恢复过来。在调查期结束时进行的人工营养的长期效益非常有限，这是由于用于营养的沉积物太细，而且沉积物在海滩上的位置太高。显然，营养干预措施必须考虑到自然沉积物分布和剖面形状，以避免营养沉积物的迅速流失。
This paper addresses the changes in the morphology and sedimentology of a micro-tidal mixed sand and gravel beach (Playa Granada, southern Spain) forced by wave and water-level variations, and human intervention through nourishment. Monthly and storm event-driven beach surveys, consisting of topographical measurements and sediment sampling in two selected areas, were carried out over a one-year period. Three prevailing sediment fractions (sand, fine gravel and coarse gravel) and two end-member morphological states of the upper beach profile (convex with multiple berms and concave with a single storm berm) were identified. Between them, several transitional profiles were formed, characterized by developing berms that progressively overlapped, generating sediment variability both across the beach profile and with depth. The results indicate that the total run-up (including water-level) reached during an event represents a more accurate threshold for differentiating between erosional and depositional conditions than wave height. They also suggest that mixed sand and gravel beaches recover faster from storm erosion than sandy beaches. The long-term benefit of the artificial nourishment that took place at the end of the survey period was very limited and this is attributed to the too fine sediment used for the nourishment and its placement too high on the beach. Clearly, nourishment interventions must take into account the natural sediment distribution and the profile shape to avoid rapid losses of the nourished sediment.