Tidal divides

The Wadden Sea consists of a series of tidal basins which are connected to the North Sea by tidal inlets. Each lagoon has as boundaries the mainland coast, the barrier islands on both side of the tidal inlet, and the tidal divides behind the two barrier islands. Behind each Wadden Island there is a tidal divide separating two adjacent tidal basins. The locations of the tidal divides in the Wadden Sea are not fixed. Especially after a human interference, a tidal divide can move and thereby influences the distribution of area between the basins, which is important for the morphological development of the basins. Two types of tidal divides can actually be identified behind each island: the hydraulic tidal divide and the morphological tidal divide. These do not necessarily have the same position, and their location is an indicator for the equilibrium of the adjacent basins. This paper describes theoretical analyses meant for improve the insights into the location of the tidal divides and their movements, as are observed in the Dutch part of the Wadden Sea in the last 80 years.