Monitoring of the evolution of a nourished beach in San Sebastian (N. Spain)

The Spanish General Directorate of Coasts, belonging to the Secretaria de Estado de Aguas y Costas, Ministry of Environment, has replenished the former existing beach of "Zurriola" in San Sebastian. The nourishment works on the beach ended in May 1995, and since then a comprehensive monitoring scheme has been defining the behaviour of the newly replenished beach. The monitoring of the evolution is being sponsored by the MAST3-SAFE programme, held by the UE (General Directorate for Science, Research and Development and by the General Directorate of Coasts). The surveillance studies of the beach system include bathymetry and topography, sedimentology, tides, currents and wave measurements and a video camera system recording one snapshot of the beach every hour. The authors show the techniques and instrumentation used for the different tasks, and the results of the two first years of surveillance. In general the beach has shown to behave similar to what was expected, and major sand losses have been found to be due to storms, being these dramatic changes slowly compensated by minor gains throughout favourable sea states.