We have formulated an aggregated-scale behaviour-model for the interaction between a tidal basin and its adjacent coastal environment, without adopting a priory assumptions about their independent dynamic equilibrium behaviour. Necessarily so, the model combines observations and findings resuhing from analogical model applications. The model formulation is based on earlier concepts regarding the response of individual tidal system elements on a disturbance from their dynamic equilibrium state. Here, we have extended the earlier work by including interactions with the ebb-tidal delta and the directly adjacent coast. Results for schematized and real cases are discussed.