Influence of tides and river inputs on suspended sediment transport in theRia de Aveiro lagoon, Portugal

In this work the influence of tides and river inputs on suspended sediment distribution in the Ria de Aveiro, a shallow lagoon situated in the Northwe st of Portugal, has been studied. Particular emphasis has been placed on La ranjo Bay, a sub-system of the lagoon from a bio-geophysical point of view. The study is based on both data analysis and sediment transport modelling. Tides are the major factor influencing the hydrodynamics of the lagoon. Th eir effects are important even at the upper reaches of the different channe ls, where salinity, temperature and sediment concentrations change during t he tidal cycle. Sediment concentration shows both semi-diurnal and fortnigh tly periodicity. Highest values are found in the northern channels due to e rosion induced by high current speeds in shallow areas. Erosion and deposit ion are the dominant processes determining suspended sediment transport in the lagoon. (C) 2001 Elsevier Science Ltd. All rights reserved.