Storm surge hydrographs and characteristics along the Dutch coast. An analysis from simulation data

Abstract

This study analyzes storm characteristics and surge hydrographs corresponding to extreme storms in the Dutch coastal area, using a large dataset from simulated time series. A total of 8,000 storm events were selected for four study locations, allowing for a comprehensive investigation of various storm characteristics. Findings reveal that the offset between maximum surge and astronomical high tide typically exhibits three predominant values. A new percentile method for averaging storm surge hydrographs was employed, effectively preserving a realistic shape of the storm surge hydrograph and accurately reflecting durations. Comparing the averaged storm surge hydrographs for different magnitudes of the surge peak shows that it is possible to scale the averaged storm surge hydrograph to any peak value, as long as storms are first clustered based on location, tidal offset, and exceedance duration, since these characteristics substantially impact the shape of storm surge hydrographs. Comparisons with current design guidelines show that prescribed storm surge hydrographs often underestimate durations on the flanks of storm events, with variations in peak characteristics depending on location. The insights gained in this study, can be used to improve the representation of hydraulic loads in flood defense guidelines, potentially leading to more accurate flood safety assessments for coastal infrastructure.