Les Sables d'Olonne
Initial characteristics of the beach :
Both the DDE 85 Marine service, who has been monitoring Les Sables d’Olonne Beach since 1970, and SOGREAH, who carried out a survey in 1990, revealed that the beach profile was lowering due to erosion.
The threat of beach disappearance in the long run, coupled with the collapse of hard coastal protection, urged the municipality to consider different solutions.
- Erosion of 30cm per year
- Meaning 1000 m3 of sand carried
- Endangered infrastructures
- Beach saturated with water
Ecoplage® installation works - 1999 and 2002 :
700 meters of drains were installed on the upper part of the beach and 600 meters in the middle of the beach. The seawater captured by these two lines of drains flows by gravity to the pump station, equipped with 2 pumps of 250m3/h. This water is then rejected back to the sea thanks to a discharge pipeline.
Observations since the installation of the Ecoplage® system :
Erosion stoppage and natural beach nourishment
- Increase in beach width
- Natural nourishment of 40 to 50 cm (vertical)
- Drying up of the beach during low tide
- Less variations in beach profile
- Transfer of sand from the bottom part to the upper part of the beach (around 20 000 m3 )