Evaluation of the longshore current for a sector of the Portuguese west coast: Application of different methodologies

The aim of the study is to evaluate the longshore current in the coastal sector Figueira da Foz - Nazare of the Portuguese West coast. The knowledge of this hydrodynamic parameter along the coast allows to estimate the longshore sediment drift and also to predict the displacement of buoyant load. Three different types of methodologies were applied: two types of process-based mathematical models; several empirical formulations; and a field experiment. A monitoring data program (for waves and currents) was also implemented to support the field experiment and to provide input conditions for the numerical simulations and the empirical formulations. For typical wave conditions the longshore current found in this sector was up to 1.5 m/s. The technique used in the field to measure the wave-induced longshore current at the sea surface proved efficient. The empirical formulations and the numerical models have produced consistent results.