Departamento de Ingeniería Aeroespacial y Mecánica de Fluidos, Universidad de Sevilla, Camino de los Descubrimientos s/n, 41092 Seville, Spain.
Departamento de Ingeniería Aeroespacial y Mecánica de Fluidos, Universidad de Sevilla, Camino de los Descubrimientos s/n, 41092 Seville, Spain.
Sci Total Environ. 2019 Mar 25;658:1069-1084. doi: 10.1016/j.scitotenv.2018.12.227. Epub 2018 Dec 21.
Despite relevant advances achieved in recent years, sediment transport and sedimentation problems at tidal inlets are still worldwide issues to be addressed. Furthermore, dredging strategies are carried out following traditional layouts, such as channel deepening, lasting short periods of time despite the high economic expenditures and the potential environmental impacts. This work proposes a new dredging strategy for tidal inlets and analyzes its morphodynamic evolution by means of numerical modeling. This numerical model, used to perform hydro-morphodynamic simulations, is applied to a highly altered tidal inlet (Punta Umbría inlet, Southern Spain) with a navigational capacity being continuously compromised. After calibrated and tested, the model is applied to different dredging strategies, including channel deepening, littoral drift barrier and shoal removal. Among these strategies, the shoal removal, which is a new soft-engineering strategy, is found to be the most efficient to improve the navigational channel operativity, defined as the percentage of navigable hours per year for different vessel drafts; this operativity improves up to 60% compared to the other strategies. This solution, which reduce the frequency of maintenance interventions and hence the environmental impacts, may be suitable for other inlets with compromised navigational capacities due to the presence of ebb shoals. The relation between the main maritime drivers and the morphodynamic changes is analyzed, concluding that the morphodynamic evolution of the navigational channels is closely related not only to the wave energetic content, but largely to the wave directionality. Finally, the shoal removal also increases the flow velocities at the inlet modifying the stability of the mouth and hampering its long-term closure. The potential environmental impacts derived from the shoal removal are also discussed.
尽管近年来取得了相关进展，但潮汐入口处的泥沙输移和淤积问题仍然是全球需要解决的问题。此外，疏浚策略是按照传统的布局进行的，例如航道加深，尽管经济支出高且潜在的环境影响大，但持续时间很短。本工作提出了一种新的潮汐入口疏浚策略，并通过数值模拟分析了其形态演变。该数值模型用于进行水动力形态模拟，应用于一个高度变化的潮汐入口（西班牙南部的蓬塔乌姆布里亚入口），其通航能力不断受到影响。模型经过校准和测试后，应用于不同的疏浚策略，包括航道加深、沿岸漂移障和浅滩清除。在这些策略中，浅滩清除是一种新的软工程策略，被发现是改善通航通道操作性最有效的策略，操作性定义为每年不同船舶吃水的可通航小时数；与其他策略相比，操作性提高了 60%。这种解决方案减少了维护干预的频率，从而减少了环境影响，可能适用于其他由于存在落潮流浅滩而通航能力受损的入口。分析了主要航海驱动因素与形态演变之间的关系，得出结论，通航通道的形态演变不仅与波浪能量含量密切相关，而且在很大程度上与波浪方向性有关。最后，浅滩清除还增加了入口处的流速，改变了河口的稳定性，阻碍了其长期封闭。还讨论了浅滩清除带来的潜在环境影响。
