Connecting subtidal and subaerial sand transport pathways in the Texel inlet system

Potential transport pathways between the subtidal and subaerial part of tidal inlet systems are explored by means of a case study of Texel Inlet, The Netherlands. Based on a morphologic analysis of multi-annual, high-resolution bathymetric and topographic data sets we hypothesize that two mechanisms connect the subtidal and subaerial parts of the system. The first mechanism relates to deposition on the tip of the island occurring to a large extent below spring high tide level, providing a fresh sediment source available for aeolian transport during parts of the tidal cycle. The second mechanism relates to sand deposition on the wide sandflat above spring high tide level occurring during storm surge flooding. These deposits are then available for aeolian transport during regular water levels. Due to the dominant wind direction at Texel Island, this leads to extensive dune formation on the downwind end of the sandflat.Policy AnalysisCoastal Engineerin

Beach-dune modelling in support of Building with Nature for an integrated spatial design of urbanized sandy shores

The long-term physical existence of sandy shores critically depends on a balanced sediment budget. From the principles of Building with Nature it follows that a sustainable protection of sandy shores should employ some form of shore nourishment. In the spatial design process of urbanized sandy shores, where multiple functions must be integrated, the knowledge and the prediction of sediment dynamics and beach-dune morphology thus play an essential role. This expertise typically resides with coastal scientists who have condensed their knowledge in various types of morphological models that serve different purposes and rely on different assumptions, thus have their specific strengths and limitations. This paper identifies morphological information needs for the integrated spatial design of urbanized sandy shores using BwN principles, outlines capabilities of different types of morphological models to support this and identifies current gaps between the two. A clear mismatch arises from the absence of buildings and accompanying human activities in current numerical models simulating morphological developments in beach-dune environments.Vol. 7 (2021): Building with Nature perspectives: Cross-disciplinary BwN approaches in coastal regions. ISBN 978-94-6366-379-3Landscape Architectur