Impact of flood defences and sea-level rise on the European Shelf tidal regime

• The tides of the European Shelf are sensitive to moderate (<1m) levels of sea level rise.
• The model is able to capture the observed tidal response to sea level rise.
• Simulations with flood defences show the strongest tidal response.
• We suggest that the tidal response to sea level change is controlled by the spatial distribution of tidal energy dissipation.

The tidal response of the European Shelf to moderate (<1m) levels of sea level rise is investigated using a high resolution, well established tidal model. The model is validated for present day conditions and the tidal response to sea level rise by comparing the modelled response to long term tide gauge data. The effects of coastal defence schemes are tested, with three levels of present day coastal defences simulated. Full walls are added at the present day coastline, no coast defence schemes are used and a set of present day coastal defence schemes is simulated. The simulations show that there is a significant tidal response to moderate levels of SLR and that the response is strongly dependant on level of coastal defence simulated. The simulation using coastal defence data resulted in the strongest response as the tide was able to build up behind the coastal defence walls and create a patchwork of sea and land at the coastline. This had a strong impact on the spatial tidal energy dissipation field and in turn this has large effects on the tidal regime throughout the domain.