A model of the morphological behaviour and stability of channels and flats in tidal basins

In this report, a model is derived which simulates the behavior of channels and flats in a tidal basin after a change in the exogenous parameters. In chapter 1, a short introduction is given about the context in which this research has been done. Chapter 2 discusses the general features of the tidal inlet system as well as its formation and classification. Also, an overview is given of the empirical relationships that have been derived. In chapter 3, the shoaling process in a tidal basin is analyzed. Because of a slight deformation of the tidal wave, the tide-integrated residual transport flux causes the tidal basin to fill in. The continued influx of sediment will induce the growth of tidal flats, which are inundated during only part of the tidal cycle. These tidal flats in turn produce a mechanism which stops the import of sediment into the tidal basin. This means that an equilibrium relative tidal flats area exists. In chapter 4, a model is derived based on the assumption that the behavior of the basic elements, the channels and the flats, is controlled by certain variables which try to attain their equilibrium value. These variables are the channel's cross-sectional area, the flats' surface area and the depth over the flats. With this model, four different scenarios, namely a partial closure of the tidal basin, a sea level rise, an increase in tidal range and a periodicity in the tidal range amplitude have been simulated. All these scenarios have been stacked to reproduce the morphological behavior in the Zoutkamperlaag , the Netherlands , which has undergone great changes since the closure of the Lauwerszee in 1969. Finally, a short assessment is made of the influence a changing tidal basin has on the other elements in the tidal inlet system.