Coastal flood protection by a combined nature-based and engineering approach: modeling the effects of marsh geometry and surrounding dikes
Coastal flood protection by a combined nature-based and engineering approach: modeling the effects of marsh geometry and surrounding dikes
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通过基于自然和工程相结合的方法进行沿海防洪：对沼泽几何形状和周围堤坝的影响进行建模
DOI：
10.1016/j.ecss.2016.03.027
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发表时间：
2016
影响因子：
2.8
通讯作者：
S. Temmerman
中科院分区：
文献类型：
--
作者：
Jeroen Stark;Y. Plancke;S. Ides;P. Meire;S. Temmerman
随着以生态系统为基础的全球变化适应措施的日益普及，除了传统的海岸防御结构外，保护沿海和河口地区免受日益严重的洪水危害的战略也开始包括自然潮汐湿地的保护和恢复。在这项研究中，潮汐湿地的能力，局部衰减峰值水位在风暴潮期间进行了分析，使用二维水动力学模型（TELEMAC 2D）为3000公顷的潮间带沼泽（荷兰西南部）。模型结果表明，峰值水位降低很大程度上不同的个人洪水事件和沼泽中的不同位置之间。不同堤坝位置的模型场景表明，可以通过堵塞和针对堤坝或限制沼泽大小的其他结构设置水位来最大限度地降低衰减率。如果洪水波的持续时间比沼泽的大小长，这种阻塞只会影响湿地的峰值水位衰减。在本研究中评估的风暴潮情况下，需要6-10 km的最小沼泽宽度以完全避免阻塞效应。如果堵塞不影响洪水波的传播，在沼泽中的不同位置之间的衰减率的变化和不同的高水位之间的潮汐可以解释与一个单一的关系的基础上的沼泽平台上的水量和平台上的总水量和渠道之间的比率。当该比率超过0.2-0.4时，衰减开始发生，并且从那里开始增加，直到最大值29 cm/km，比率约为0.85。此外，不同的沼泽通道深度的模型方案表明，沼泽规模的衰减率增加到4厘米/公里，如果通道海拔平均提高0.7米。相反，沼泽规模的衰减率降低了高达2厘米/公里的情况下，渠道平均降低了0.9米。沼泽台地高程对最大衰减影响不大，但它决定了衰减的潮汐。特别是，只有淹没平台的沼泽潮汐被衰减，而只有淹没沼泽通道的沼泽潮汐不会被衰减甚至被放大。这些研究结果可以帮助沿海社区和管理人员在优化结合堤防潮汐湿地的海防功能。
As ecosystem-based adaptation to global change is gaining ground, strategies to protect coastal and estuarine areas from increasing flood hazards are starting to consist of natural tidal wetland conservation and restoration in addition to conventional coastal defense structures. In this study, the capacity of tidal wetlands to locally attenuate peak water levels during storm tides is analyzed using a two-dimensional hydrodynamic model (TELEMAC2D) for a 3000 ha intertidal marsh (SW Netherlands). Model results indicate that peak water level reduction largely varies between individual flooding events and between different locations in the marsh. Model scenarios with variable dike positions show that attenuation rates can be minimized by blockage and set up of water levels against dikes or other structures confining the marsh size. This blockage only affects peak water level attenuation across wetlands if the duration of the flood wave is long compared to the marsh size. A minimum marsh width of 6–10 km is required to completely avoid blockage effects for the storm tidal cases assessed in this study. If blockage does not affect flood wave propagation, variations in attenuation rates between different locations in the marsh and between tides with varying high water levels can be explained with a single relationship based on the ratio between the water volume on the marsh platform and the total water volume on the platform and in the channels. Attenuation starts to occur when this ratio exceeds 0.2–0.4 and increases from there on up to a maximum of 29 cm/km for a ratio of about 0.85. Furthermore, model scenarios with varying marsh channel depth show that marsh scale attenuation rates increase by up to 4 cm/km if the channel elevation is raised by 0.7 m on average. Conversely, marsh scale attenuation rates decrease by up to 2 cm/km for scenarios in which the channels are lowered by 0.9 m on average. The marsh platform elevation has little effect on the maximum attenuation, but it determines which tides are attenuated. In particular, only overmarsh tides that inundate the platform are attenuated, while undermarsh tides that only flood the marsh channels are not attenuated or even amplified. These findings may assist coastal communities and managers in the optimization of the coastal defense function of tidal wetlands in combination with dikes.