On the relationship between the Óbidos lagoon inlet migration path and the offshore wave power

Abstract

The inlet of the Óbidos Lagoon is a wave-dominated tidal inlet located on the Portuguese coast. It is known for its unstable behaviour, which often leads to erosion issues on its margin or to its complete closure. Over twenty years of satellite data were compiled to document this behaviour. The reconstructed behaviour was compared to the contemporary offshore wave climate. The comparison showed that the inlet’s preferred migration direction could differ from the relative orientation of the offshore wave power; it was particularly the case when the longitudinal component of the wave energy flux strongly or durably deviated from its long-term average. In contrast, the inlet closed more frequently when this deviation was smaller.