On the Atlantic coast, in the littoral of the department of Vendée, the beach of les Sables d’Olonne extends on 1500 meters on the bottom of a bay, well protected against the dominant west swells, by headlands and shoals.

Since the beginning of the nineteenth century, the level of the upper shore is lowered, due to the erosion of the beach. This erosion causes some risks on the foundations of the seawall and the seaside resort built behind, and the reduction of the usable beach at high tide for the tourists. The cross-shore transport, mainly and the long-shore transport make an erosion about 1.000 cubic meters each year.

The environment and the landscape of this famous seaside resort could not be disturbed by hard protections like groins, rocks, breaking-waves…The solution of a beach-nourishment has been studied, but the local authorities have decided to tried a beach drainage system called ECOPLAGE® in France (Beach Management System). A first drain (300 meters) has been installed in the east section of the beach in 1999, and a second has been installed in March 2002, on the west section (300 meters), and a third (700 meters) between the first drain and the seawall.

The result of the first operation is a stabilisation of the beach profiles treated while the untreated beach is continuing to be eroded. The drying of the beach, and a better recovery of sand by the system after storm events, have been verified. The results of the second operation seem to be better, with natural nourishment visible above the system.

• Study area: 1,5 km; Sedimentary cell: 3,5 km
• Type of coast: hard rock coast and beaches (with fine-medium sand)
• Tidal regime: macro tidal (around 5.5m)
• Range of waves : mean Hsig = 1-3 m