Impact of morphologic anthropogenic and natural changes in estuarine tidal dynamics

In this paper is outlined the application of a hydrodynamic model for the assessment of tidal changes induced by the impact of estuarine morphologic man-made and natural modifications. In fact, anthropogenic activities and changes in natural environments affect tidally dominated coastal environments making it more vulnerable. Thus, the main aim of this work is to address the impact of these problems in coastal systems, studying the particular case of the Ria de Aveiro. A hydrodynamic model previous implemented for this system is used to investigate changes in tidal amplitude and phase and its sensitivity to three bathymetric settings: one representing the past conditions, other representing the present (corresponding to the inlet channel deepening) and a third bathymetry representing a future scenario assuming the enlargement of the lagoon flooded area. The amplitude and phase of the M2 and K1 tidal constituents were computed for twenty nine stations distributed along the main channels of the lagoon. The tidal prism was also computed for the three bathymetric settings for five cross sections in the central area of the lagoon. Generally, the model results suggest that over the last years, the amplitude of the tidal constituents has increased and its phase has decreased. When the enlargement of the flooded area is assumed, a slight decrease in its amplitude and an increase in its phase lag are observed. The tidal prism at the mouth has increased more than 6% over the last years and the enlargement of the flooded area further increases the tidal prism.