The Impact of Submerged Breakwaters on Sediment Distribution along Marsh Boundaries
The Impact of Submerged Breakwaters on Sediment Distribution along Marsh Boundaries
复制标题
水下防波堤对沼泽边界沉积物分布的影响
作者：
I. Vona;M. Gray;W. Nardin
人类对海岸线的侵蚀和开发导致了更多的海岸线装甲。防波堤是沿着海岸线的常见特征，用于抑制波浪能量并保护海岸线免受山洪暴发或过冲事件的影响。虽然它们很常见，但对沉积物迁移和沼泽地貌的影响了解甚少。为了解决这一差距，我们的研究量化的影响，防波堤上的泥沙输运和沼泽演变在不同的波制度，使用Delft 3D-SWAN，一个动态的地貌动力学数值模型。模型配置使用相同的数值域，但情景具有不同的沉积物、波浪、潮汐、盆地坡度和离海岸线的防波堤距离，以探索波浪和潮流如何塑造海岸边缘。模型结果表明，防波堤的平均波浪阻尼在10- 50%之间，与所有模拟场景中的有效波高成比例。剪切应力在沼泽的开始和沉积物的体积在模拟结束时（进入沼泽后面的防波堤）平均增加20- 40%之间，成比例的斜坡和距离的防波堤从海岸线。沉积物截留，被定义为之间的比率容纳到盐沼后面的沉积物的体积和远离防波堤，被发现是小于1，从大多数模型运行。研究结果表明，防波堤有利于波浪破碎，以保护海岸线从波浪的能量，但是，他们也可能是一个障碍，泥沙输运，负面影响营养过程，因此，阻碍了长期盐沼生存。在设计和实施这些结构时，应考虑在波浪阻尼和海岸线营养之间取得平衡。
Human encroachment and development on coastlines have led to greater amounts of armoring of shorelines. Breakwaters are a common feature along coastlines, which are used to dampen wave energy and protect shorelines from flash floods or overwash events. Although common, their effects on sediment transport and marsh geomorphology are poorly understood. To address this gap, our study quantifies the effects of breakwaters on sediment transport and marsh evolution under different wave regimes using Delft3D-SWAN, a dynamic geomorphodynamic numerical model. Model configurations used the same numerical domain, but scenarios had different sediments, waves, tides, basin slopes and breakwater distances from the shoreline to explore how waves and tidal currents shape coastal margins. Model results suggested breakwaters were responsible for an average wave damping between 10–50%, proportional to the significant wave height across all modeled scenarios. Shear stress at the beginning of the marsh and the volume of sediment deposited at the end of the simulation (into the marsh behind the breakwater) increased on average between 20–40%, proportional to the slope and distance of the breakwater from the shoreline. Sediment trapping, defined as the ratio between the volume of sediment housed into the salt marsh behind and away from the breakwater, was found to be less than 1 from most model runs. Study results indicated that breakwaters are advantageous for wave breaking to protect shorelines from the wave’s energy, however, they might also be an obstacle for sediment transport, negatively affecting nourishment processes, and, consequently, impeded long-term salt marsh survival. Identifying a balance between waves dampening and shoreline nourishment should be considered in the design and implementation of these structures.
影响因子：
64.8
作者：
Schuerch, Mark;Spencer, Tom;Brown, Sally
通讯作者：
Brown, Sally