This thesis describes the development and the characteristics of the coastline along the Dutch coastal zone, managed by Hoogheemraadschap Hollands Noorderkwartier. The coastal zone is a rich environment with multiple stakeholders. These stakeholders use the coastal zone for a range of functions such as safety, nature, business, and recreation. Coastal dunes have been the first line of defense against the sea for many years. On decadal and intercentennial time scale, climate change (e.g. sea level rise) and human intervention (e.g. nourishment), affect the variability of the coastline in different ways. Reports have shown an increase of the mean sea level, which is expected to increase even after the year 2100. Bruun was one of the first researchers, who found a relation between sea level rise and shoreline recession. While Bruuns findings contain the fundamental adaption of the coastline due to sea level rise, the coastline remains a highly complex system. Morphological data has been collected yearly of the Dutch coast as part of the JarKus program. Meanwhile, the data collection and computational power have increased exponentially, while the computational cost has gone down. Combining the newly computational power with the extensive JarKus data set, provides new insight into the complex coastal system. The derived variables from the JarKus data set range from widths, gradients, volumes to heights. These derived variables are combined with nourishment into a high-dimensional data set. Clusters of comparable coastal profiles in the Hoogheemraadschap Hollands Noorderkwartier area, have been made using machine learning techniques. Machine learning techniques such as K-means and the Self-Organizing Map (SOM) contain an intelligence, with the capability of clustering similar high-dimensional objects or data, without knowing the desired output. While both methods have the same goal, K-means moves its centroids inside the data and the SOM moves the data to its centroids (BMU). The advantage of combining both methods, is to keep the topological preservation while having the 'hard' clustering advantage of the K-means, which provides easy interpretation and therefore computations. The coastline of the Noorderkwartier can be broken up into nine clusters. Five of these clusters are classified as main-clusters, having a large number of transects. Four clusters are classified as sub-clusters, having just a few transects. Each of the clusters contains its own characteristic variables. Each of these characteristics originates from its own long-term natural and human-induced causes. The variable dominating the general clustering, is the active profile of the coastline. The lesser dominating variables are the foreshore nourishment, depth of closure and increase in foreshore volume. Meaning that the high-dimensional data set, find their similarities due to these dominant variables. Upon further investigation, the clusters containing the highest active profiles, were also the clusters containing historical larger nourishments. Comparing the yearly change of the standard deviation, shows that the clusters containing larger historical nourishment, have a shifting depth of closure. With respect to the dunes, correlations are found between the dune foot, y-coordinate of the boundary between marine and aeolian transport, dune volume and active width of the dune. While the exact reason for this correlation is still unknown, it shows potential for further research. The results of this research contribute to another step in understanding the complex coastal zone. Hoogheemraadschap Hollands Noorderkwartier can now adjust its policy and approach for each cluster based on the results of this research. For further research, it is now possible to focus on specific clusters with their unique characteristics. Lastly, results highlight the importance of the effect of nourishment on the active profile and with this the future dynamic equilibrium of the coastline.

'De Slufter' is a nature conservation area located in the Northwest of the Dutch Wadden island Texel which is inundated with seawater during storm events. The landward side of De Slufter is a sand dike which is part of the primary coastal defence ring of the island. HHNK, which is responsible for the coastal safety of Texel, currently relocates the dynamic gully in the slufter mouth every time it reaches one of the dune heads (every 5-6 years approximately) because uncontrolled gully migration might widen the slufter mouth. This could lead to more wave attack on the sand dike, possibly affectingthe coastal safety of Texel. Still, HHNK is planning on ceasing the relocations of the gully. The goal of this thesis is to assess the effects on the present and future coastal safety of De Slufter. First, based on a field data analysis of annual topography and bathymetry measurements it is expected that the gully migration is governed by wave-induced longshore transport, curvature-induced secondary flow due to tidal forcing, overwash from the beach flat into the gully during storms and by the distance to the dune heads (which inhibits migration) To investigate the effect of ceasing relocations of the gully on present and future coastal safety a modelling study was performed with XBeach Surfbeat. 15 scenarios were created to assess the effects of different bathymetry and of sea level and bed level rise
Failure was assessed on two failure mechanisms: 'Grensprofiel', which consists of two aspects. A minimum sand dike volume above storm surge level must be available in every transect alongshore in the sand dike. Also, each post-storm sand dike transect must be large enough to contain a legally defined 'limit profile'. The second mechanism is 'Initiation of flooding', which means that failure occurs when at any point landward of the 'Waterstaatswerk' boundary (the outer border of the primary coastal defence) a depth of at least 20 cm is observed. In all present scenarios no failure occurs for a normative 1/3000 year storm. De Slufter is therefore considered 'safe'. Maximum wave heights did not increase significantly for different bathymetry configurations due to the large amount of dissipation occurring in the slufter valley. No overwash or overtopping occurred in any of the modelled scenarios and morphological impact on the sand dike itself was relatively low. Failure does occur for the 1/3000 year storm with a sea level rise of 1.95 m and 3.17 m. Failure does not occur in the middle of the sand dike where the majority of the wave attack happens but in the southwestern and northeastern parts due to inundation over the ridge there (‘Initiation of flooding’). It is expected that the 'tipping point' of De Slufter, which is the sea level rise magnitude beyond which De Slufter does not adhere to safety standards, is at a sea level rise magnitude of 1.70 m.