The 1717 Christmas flood is one of the most catastrophic storm surges the Frisian coast (Netherlands and Germany) has ever experienced. With more than 13,700 casualties it is the last severe storm surge with a death toll of this order. At the same time, little is known about the hydrodynamic conditions and the morphological effects associated with this storm surge.In this study, 41 potential dyke failures in the Province of Groningen (Netherlands) associated with the 1717 Christmas flood were systematically reconstructed and mapped by using historical maps and literature and by analysing the recent topography in search of typical pothole structures and sediment fans. The dimensions of the sediment fans as derived from the topography show a good accordance with the dimensions documented by vibracore profiles, direct push tests and electrical resistivity tomography data taken at three fieldwork sites. Moreover, the fan dimensions closely agree with the dimensions as simulated using a process-based morphodynamic numerical model for one of the three sites, the village of Wierhuizen. Consequently, the recent topography is still indicative for the locations and dimensions of dyke failures and sediment fans associated with the 1717 Christmas flood. Considering the large number of detected dyke failures (41) and the large dimensions of the potholes and particularly of the sediment fans up to a few hundred metres wide and up to 0.7 m thick, this study proves significant morphological effects of the 1717 Christmas flood on the mainland of the Province of Groningen.Based on the numerical simulation approach and the comparison with field data and field observations, a maximum seaward water level of 5 m NAP for the dyke failure at Wierhuizen during the Christmas flood can be derived. A similar maximum water level is indicated for the two other fieldwork sites Vierhuizen and Kohol, which is in good agreement with the maximum storm surge level of 4.62 m NAP historically documented for the city of Emden located almost 50 km to the east of Wierhuizen.The results of the current study demonstrate that the reconstruction of historical dyke failures based on (i) historical sources, (ii) recent lidar/high-resolution topographical data, (iii) multi-proxy sedimentary field data and (iv) hydro- and morphodynamic numerical simulations is a highly promising approach to derive hydrodynamic conditions and the morphological onshore response of the 1717 Christmas flood in the Province of Groningen. This knowledge is essential to improve our understanding of extreme storm surge dynamics, their influence on the coastal landscape and the associated hazards for the coastal population.

中文翻译：

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与 1717 年圣诞洪水相关的格罗宁根省（荷兰）的堤坝破坏：基于地球科学现场数据和数值模拟的重建

1717 年的圣诞洪水是弗里斯兰海岸（荷兰和德国）经历过的最具灾难性的风暴潮之一。有超过 13,700 人伤亡，这是最后一次造成此级别死亡人数的严重风暴潮。与此同时，人们对与这次风暴潮相关的水动力条件和形态影响知之甚少。在这项研究中，格罗宁根省（荷兰）与 1717 年圣诞洪水相关的 41 处潜在的堤坝故障被系统地重建并绘制了地图。使用历史地图和文献，并通过分析最近的地形来寻找典型的坑洼结构和沉积扇。从地形推导出的沉积物扇的尺寸与振动芯剖面记录的尺寸非常吻合，在三个现场工作地点采集的直推测试和电阻率断层扫描数据。此外，风扇尺寸与使用基于过程的形态动力学数值模型模拟的尺寸非常吻合，用于三个地点之一，即 Wierhuizen 村。因此，最近的地形仍然可以指示与 1717 年圣诞节洪水相关的堤坝破坏和沉积物扇的位置和尺寸。考虑到检测到的大量堤坝破坏 (41) 以及坑洞的大尺寸，特别是高达几百米宽和高达 0.7 m 厚的沉积扇，这项研究证明了 1717 年圣诞节洪水对格罗宁根省的大陆。基于数值模拟方法以及与现场数据和现场观测的比较，可以推导出Wierhuizen在圣诞节洪水期间堤坝破坏的最大向海水位为5 m NAP。其他两个实地考察地点 Vierhuizen 和 Kohol 也显示了类似的最高水位，这与历史记录的位于 Wierhuizen 以东近 50 公里的 Emden 市的最大风暴潮水平 4.62 m NAP 非常吻合。目前的研究结果表明，基于 (i) 历史来源，(ii) 最近的激光雷达/高分辨率地形数据，对历史堤坝故障的重建，(iii) 多代理沉积现场数据和 (iv) 水动力和形态动力学数值模拟是推导格罗宁根省 1717 年圣诞洪水的水动力条件和形态陆上响应的非常有前景的方法。这些知识对于提高我们对极端风暴潮动态、它们对沿海景观的影响以及对沿海人口的相关危害的理解至关重要。