DRIFT – Dune Response and Interpretation Framework for Decadal Topographic Change: Assessing potential drivers of observed foredune growth under coastal progradation and shoreline maintenance on decadal timescales. Internship Research Report
Van de Velde, A. (2026). DRIFT – Dune Response and Interpretation Framework for Decadal Topographic Change: Assessing potential drivers of observed foredune growth under coastal progradation and shoreline maintenance on decadal timescales. Internship Research Report. Course certificate Thesis. Utrecht University: Utrecht. 121 pp.
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| Abstract |
This report investigates dune-related topographic change along maintained sandy coasts of the North Sea, using the Belgian coast as the core case and selected sites in the Netherlands, Germany, and Denmark as comparative examples. Developed within the MANABAS COAST context, the study aimed to assess to what extent dune-growth rates and patterns along the Belgian coast resemble those of other maintained North Sea coasts, and how such behaviour can be compared consistently across countries.
To address this, a LiDAR-based workflow was developed to quantify long-term elevation change across selected beach–dune profiles. The method combines surface-volume analysis by elevation interval with transect-based profile comparison and applies a conceptually harmonised zoning approach using site-specific reference thresholds. Belgium was analysed through three sites (De Panne, De Haan, and Knokke-Heist), while comparison sites were selected in the Netherlands, Germany, and Denmark.
The results show that most analysed sites exhibit net positive dune-related sediment accumulation over decadal timescales, but with clear differences in magnitude, spatial expression, and profile response. Within the Belgian core case, all three sites remained net positive, with De Panne showing the strongest and most coherent response, De Haan a more spatially variable intermediate response, and Knokke-Heist the weakest overall net accumulation. The strongest positive signals in the wider comparison were observed at the Sand Engine and Petten, while the German sites showed more modest positive responses and the Danish comparison included both a strongly positive and a clearly negative end member. The exceptionally high values at the Sand Engine and Petten should, however, be interpreted in the context of major nourishment interventions rather than as purely autonomous dune growth.
The comparison further suggests that inter-site differences are most plausibly related to interacting controls on sediment supply, beach–dune pathway continuity, local coastal configuration, hydrodynamic and aeolian forcing, and management history. At the same time, these explanatory links remain interpretative, because the applied workflow quantifies integrated morphological response rather than directly isolating individual controlling mechanisms.
Overall, the study demonstrates that cross-country comparison of dune-related change is feasible when based on transparent and transferable indicators derived from conceptually harmonised surface-volume and transect-based analyses. The workflow therefore provides a useful first-order framework for comparing maintained North Sea coasts and a first step towards more empirical approaches for explaining and eventually predicting dune-growth behaviour under interacting environmental and management-related conditions. |
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