During storms, long-period water level oscillations can occur on the North Sea. The meteorological phenomena that cause these oscillations are known to a large extent and include atmospheric single pulse perturbations or oscillations of longer duration and larger spatial scale (De Jong in Origin and prediction of seiches in Rotterdam harbour basins, Delft University of Technology, ISBN 90-9017925-9, 2004). During such events, standing waves, or ‘seiches’, can occur in the ports along the Dutch North Sea coast. These seiches need to be considered in the height criteria for the dikes and other flood protection works around the port basins. Over the last decades, several projects on the climatology of seiching have been performed by Deltares under assignment by the Dutch Ministry of Public Works. Results of these projects served to update the height criteria for the storm surge barriers in the Port of Rotterdam, and as input to the design of two large new sea locks for other coastal ports, in IJmuiden and Terneuzen. This paper describes the three project locations: the statistical and hydrodynamical analyses of seiche events at these locations and the translation of the results into a buffer, or ‘seiche allowance’, to the height criteria.

在暴风雨期间，北海会发生长期的水位振荡。引起这些振荡的气象现象在很大程度上已广为人知，包括大气单脉冲扰动或持续时间较长且空间尺度较大的振荡（De Jong的起源和鹿特丹港盆地的生境预测，代尔夫特理工大学，ISBN 90- 9017925-9，2004）。在此类事件中，荷兰北海沿岸的港口可能会发生驻波或“塞奇”。在堤防和港口流域周围的其他防洪工程的高度标准中，必须考虑这些地形。在过去的几十年中，Deltares在荷兰公共工程部的委托下开展了数个关于气候变化的项目。这些项目的结果有助于更新鹿特丹港风暴潮屏障的高度标准，并为其他沿海港口艾默伊登和特尔尼岑的两个大型新海闸的设计提供了投入。本文描述了三个项目的位置：这些位置的塞奇事件的统计和流体力学分析，以及将结果转换为高度标准的缓冲或“塞奇津贴”。