A SPATIAL ANALYSIS OF THE DEPENDENCE BETWEEN WAVE HEIGHTS AND WATER LEVELS USING COPULAS IN THE DUTCH DELTA

The Netherlands is a low-laying country with approximately 60percent of its land vulnerable to flooding. An elaborated flood defense system composed of dikes, dunes and storm surge barriers was created to protect the large number of inhabitants and high value of assets. In coastal and delta areas, design values for flood protection infrastructures, i.e., primary flood defenses, are mainly governed by the combination of high water levels and wave heights that in extreme conditions might exhibit a significant degree of correlation due to the, often, common origin associated with intense wind (Masina et al., 2015). A misrepresentation of the underlying relationship between these variables can potentially lead to an incorrect quantification of the forcings acting on the primary protection. This study aims to (i) characterize the spatial dependencies of hydraulic boundary conditions along Dutch southwest delta from coastal to inland areas and (ii) to assess how accounting for these dependencies when estimating design values affect the safety assessment of the primary defense.