Lagrangian experiments of particle tracking were carried out in the semi-enclosed Bay of Algeciras attached
to the Strait of Gibraltar in order to investigate the flushing patterns. A high resolution three-domain-nested
hydrodynamic model provided the velocity fields from a 61-d hindcast, with the aim of analyzing the flushing
efficiency of eight different docks under a variety of external conditions, namely, tide phase and strength, and
winds. The tracking algorithm was specifically developed to exploit the high spatial resolution of the model
that reproduces the local dynamics accurately. Winds are the dominant agent, with westerlies featuring e-folding
times one order of magnitude lower than easterlies. Fortnightly tidal modulation causes a counter-intuitive
effect, with spring tides promoting higher accumulation of particles inside the docks and higher e-folding times
than neap tides. Additionally to high resolution details on the flushing patterns of the Algeciras Port, the
model also confirms the Bay as a potential feeder of floating tracers for the nearby Alboran Sea. The proposed
approach is easily scalable and exportable to other similar locations worldwide.
