Managed realignment (MR) constitutes a form of nature-based adaptation to coastal hazards, including sea level rise and storm surges. The implementation of MR aims at the (re)creation of intertidal habitats, such as saltmarshes, for mitigating flood and erosion risks and for creating more natural shorelines. However, some evidence suggests that the desired coastal protection function of MR schemes (in terms of high water level (HWL) attenuation) may be limited and it was hypothesized that this was due to the configuration of the remaining seawalls, which we refer to as scheme design. Here we present the results of a hydrodynamic model application, which we used to analyse the effects of scheme design on within-site HWL attenuation by applying six scheme designs that differ in terms of breach characteristics and water storage capacity. In specific, we vary the configuration of the seaward defence line (including the seawall breaches) and the position of the landward dike by modifying the digital elevation model of the site.

Our results show that changes in scheme design, particularly storage area and number and width of breaches, had significant effects on the site's HWL attenuation capacity. Decreasing the tidal prism by changing the number and size of breaches, with the site area kept constant, leads to increased modelled HWL attenuation rates. However, average HWL attenuation rates of >10 cm km⁻¹ are only achieved when site size increases. The mean high water depth of each scheme design scenario, calculated by dividing tidal prism by MR area, explains most of the variation in average HWL attenuation between all scenarios. Attention to potential within-site hydrodynamics at the design stage will aid the construction of more effective MR schemes with respect to coastal protection in the future.

有组织的调整（MR）构成了对沿海灾害（包括海平面上升和风暴潮）的自然适应。MR的实施旨在（重新）创造盐沼等潮间生境，以减轻洪水和水土流失的风险，并创造更多的自然海岸线。但是，一些证据表明，MR方案的所需海岸保护功能（就高水位（HWL）衰减而言）可能受到限制，并且据推测这是由于剩余海堤的构造所致，我们将其称为方案设计。在这里，我们介绍了一个水动力模型应用程序的结果，我们通过应用六个在突破特征和储水量方面不同的方案设计来分析方案设计对现场HWL衰减的影响。具体来说，

我们的结果表明，方案设计的更改，特别是存储区域以及违规的数量和宽度，对站点的HWL衰减能力有重大影响。通过改变裂口的数量和大小来减小潮汐棱镜，并保持场地面积不变，从而导致模拟的HWL衰减率增加。但是，仅当站点大小增加时，才能实现> 10 cm km ^-1的平均HWL衰减率。用潮汐棱镜除以MR面积计算得出的每个方案设计方案的平均高水深解释了所有方案之间平均HWL衰减的大部分变化。在设计阶段注意潜在的现场内部水动力将有助于将来在海岸保护方面建设更有效的MR方案。