The delta is located in a microtidal environment (maximum astronomical tidal range of 0.25 m) with predominant easterly waves (north-westerly waves are only able to act near the two lagoons due to the coastal orientation). The average significant deep-water wave height is about 1.0 m and the corresponding period about 4.0 s (Garcia et al., 1993).

A comprehensive study by a team with partners from several Spanish institutes and universities has clarified many aspects of the complicated delta behaviour. Fig. 132 shows that the shoreline rates of change (positive indicating shoreline advance and negative indicating shoreline retreat) have steadily decreased in recent decades as a result of an evolution towards a more stable configuration. See Fig. 133 and Fig. 134 for some morphological details. Existing information was analysed, field measurements have been carried out, calculations were made and a series of alternatives for protection works have been studied. It is certain that reaching a new equilibrium will take a long time. When and how to interfere in the ongoing (especially eroding) processes has not yet been decided. The decision process is a typical problem in Coastal Zone Management.