| dc.description.abstract | The Wadden Sea contains the largest contiguous area of intertidal flats in the world,
stretching along the coasts of the Netherlands, Germany, and Denmark, and is marked
as a UNESCO World Heritage Site due to its unique ecological value. With rising sea
levels, the intertidal habitats are at risk of drowning. However, it remains unclear
how the morphology within the tidal basins will react.
In this study, detailed hypsometric characterization of the Dutch Wadden Sea is carried
out to gain a better understanding of the dynamics within these tidal basins.
Hypsometry is the distribution of elevation over area within a morphological unit.
The shape of this curve can be parameterized and area, volume, and height of depth
zones can be calculated. Therefore hypsometric characterization allows for strong
data reduction. In estuary research, predictability to the pattern in concavity-convexity
of the curve has been found. This raises the question whether similar predictability is
present for tidal basins.
Results show that curve convexity and presence of intertidal habitats increase from
west to east and from the inlet to the land. The mean height of the flats decreases
away from the inlet. Furthermore, the pattern of intertidal flat area shows a negative
exponential relationship with basin size between and within tidal basins. These patterns
provide insight into the distribution of intertidal habitats in the DutchWadden
Sea and can be linked to changes in tidal range, sediment availability, wave energy,
and basin size. This is a starting point for further temporal analysis and for finding
predictability in the shape of hypsometric distributions.
Moreover, the proportion of tidal flat area is predominantly dependent on basin size,
suggesting a certain degree of self-organization in the underlying formation processes
leading to a scale-dependence of this proportion. This argues against the assumption
that the Marsdiep and Vlie basins would grow to exhibit a proportion of intertidal
flat area similar to that of the small basins in the easternWadden Sea under sufficient
sediment supply. This is often considered an equilibrium condition and strongly influences
the magnitude of predicted sediment deficits and drowning of tidal flats.
Predominant scale-dependency implies lower sediment deficits and less drowning in
the western Wadden Sea than assumed in previous studies. | |
