MORPHOLOGICAL MODELLING USING A MODIFIED MULTI-LAYER APPROACH

Henk J. Steetzel, Hans de Vroeg, Leo C. van Rijn, Jean-Marie Stam

Abstract


One of the topics of the National Dutch research program COAST*2000 focuses on the long-term (50-100 years) and large-scale (1-100 km) morphological problems of the Dutch coast and the implications for coastal management. Examples of such problems are the effects of climate change and sea-level rise on a partly protected coastline, the long-term effects of on-going sand nourishments, the far-field effects of large-scale land reclamation and of the required sand-mining etc. Within this framework a pilot version of a conceptual model (the so-called PoNTos-model) has been developed, basically capable of simulating the morphological evolution of the Dutch coast at the above-mentioned spatial and temporal scales. This present paper focuses on the theoretical background of the model. The results of a preliminary application of the model for the closed coastal section of the Dutch coast between Hoek van Holland and Den Helder are also presented. The actual PONTos-model is based on the multi-layer concept, in which the cross shore profile is schematised as a number of mutually coupled layers, defined between fixed profile depths. These layers interact through cross-shore transport. In longshore direction the layers respond to gradients in the longshore transport generated at the profile regions they represent. The main input of the model, to be provided by the user, are the characteristics of the coastal stretch to be studied, including the initial positions of the various layers and offshore hydraulic conditions in terms of wave and tidal climate tables. On the basis of these data the yearly-averaged sediment transport pattern is computed and finally used for the assessment of the coastal evolution.

Keywords


morphological modelling; modified approach; multi-layer approach

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