Implications of delta retreat on wave propagation and longshore sediment transport - Guadalfeo case study (southern Spain)
Implications of delta retreat on wave propagation and longshore sediment transport - Guadalfeo case study (southern Spain)
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DOI：
10.1016/j.margeo.2016.09.011
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发表时间：
2016-12
期刊：
影响因子：
2.9
通讯作者：
R. Bergillos;Alejandro López-Ruiz;M. Ortega-Sánchez;G. Masselink;M. Losada
中科院分区：
文献类型：
--
作者：
R. Bergillos;Alejandro López-Ruiz;M. Ortega-Sánchez;G. Masselink;M. Losada
自然和人为引起的变化对全球三角洲演变的影响已得到广泛讨论，然而，三角洲淹没形态的变化及其对海岸动力学的影响受到了有限的关注。这项工作详细介绍了瓜达尔菲奥河（西班牙南部）的河口的空间和时间的变化，并侧重于淹没形态的变化，部分是由于2004年的流域整治，波浪传播和沿岸泥沙输运的影响。在15年期间（1999-2014年）进行了水深测量，校准和应用了波浪传播模型，并使用降尺度技术应用了更新的沿岸沉积物输运表达式，以获得完整的沿岸的漂移时间序列。结果表明，拦河筑坝导致河口附近1 km范围内岸线后退，河床冲刷量沿着达3 m，最大冲刷速率超过760 m3/m。这些潮下形态的变化减少了波浪折射，并导致更高的破碎波能量。在研究期间，波浪气候的变化也发挥了影响海岸线动态的作用。虽然河口周围的侵蚀自2008年以来有所减少，部分原因是2010年的沉积物脉冲，向东沿岸沉积物输运率西风风暴波条件下，自那时以来显着增加。这导致沉积物不足向河口东部蔓延，危及该地点的城市发展。本文提供了深入了解从波浪河流为主的三角洲向三角洲海岸越来越多地控制波的方向性和沿岸泥沙输运的转变，并代表了许多世界范围内的三角洲的河流泥沙供应减少，由于人类活动的动态的理解的进步。
The influence of both natural and human-induced changes on the evolution of worldwide deltas has been widely addressed; however, the variations of the submerged morphology of the delta and their implications on coastal dynamics have received limited attention. This work details the spatial and temporal variability of the mouth of the Guadalfeo River (southern Spain) and focuses on the influence of submerged morphological changes, partly due to watershed regulation in 2004, on wave propagation and longshore sediment transport. Bathymetric measurements were carried out over a 15-year period (1999–2014), a wave propagation model was calibrated and applied, and an updated expression for longshore sediment transport was applied using downscaling techniques to obtain the complete littoral drift time series. The results show that the river damming led to coastline retreat and bed-level erosion up to 3 m along a 1-km section around the river mouth, with maximum erosion rates in excess of 760 m3/m. These subtidal morphological changes reduced wave refraction and led to higher breaking wave energy. Variations in wave climate during the study period have also played a role in influencing the coastline dynamics. Although the erosion around the river mouth has decreased since 2008, partly due to a sediment pulse in 2010, eastward longshore sediment transport rates under westerly storm wave conditions have significantly increased since then. This has led to the propagation of the sediment deficit towards the east of the mouth, endangering urban developments at this location. This paper provides insights into the shift from wave-river dominated deltas towards deltaic coasts increasingly controlled by wave directionality and longshore sediment transport, and represents an advance on the understanding of the dynamics of many worldwide deltas where the river sediment supply has decreased due to human activities.