LE BOULEVARD DE L'OCEAN

The erosion of the coast Faced with the numerous assaults of the sea, in 1851 a coastal defense syndicate was created. In 1800, the dunes still rose from 50 cm to 3 m. But in 1889, there were already no more dunes worthy of the name between the Pré-Vincent and Lyarne. It has always been necessary to build and rebuild dikes and groins to protect the salt marshes, the town and the inhabitants of Les Moutiers. It was first in the Middle Ages that the owners of the salt marshes tried to protect their property by raising causeways with pebbles and stones. It was only in the 18th century that the real works of defense of the coast began, and it was necessary to wait until the end of the second world war to see the progress of the techniques relative to this kind of construction. The history of the embankment: Boulevard de l'Océan After the storms of 1938, the Ponts et Chaussées decided to build a dike between Coëf-Barreau and Pré-Vincent. Because of the high cost, they settled for a clay dike, which was quickly damaged. So it was consolidated with piles, branches and stones and 6 groynes were erected in front of this dam. It was washed away in 1845. In 1855, a new dike was built and lined with earth and dry stones, and new groynes were planted, but this was still insufficient. In 1880, it was rebuilt with a masonry facing: it became the perré de la Maincelle. In 1889, there were only 4 houses whose owners asked for a practicable road established along the sand dyke to serve their property. In 1933, the road became a "carriageway" with traffic limitation according to the weight of the vehicles. In 1962, the road was extended from the village to the coëf-barreau. Between the two wars, at the intersection of the promenade and the Avenue de la Mer, there were two "discotheques" that attracted "foreigners" and a casino. This casino which was in fact only a hotel was replaced by the public school of girls which burned in 1923 and 1960. *Extracts from the book "Flâneries aux Moutiers-en-Retz" by Monique Albert. The last "big" storm was the Xynthia storm in 2010. The sea submerged the houses of the boulevard, destroyed many fisheries and flooded part of the town. In total, 200 houses were flooded. Since then, many works have been undertaken: the embankment has been completely redesigned. The low wall in front of the sea has been raised, with a form called "sea-catcher" on the whole boulevard of the ocean. The rear walls were made of visible stones to preserve the "character" of this space. This embankment reserved for pedestrians is today the joy of walkers. The groynes The commune of Moutiers-en-Retz, located at the bottom of the Bourgneuf Bay, extends over 6 kilometers of coastline and receives the sea from the side and not from the front. Thus, the waves, at the end of their course, are strangely oblique. Result: this inclination of the currents would have stripped the beaches if wooden groins had not been installed to retain the sand. Today, there are about 80 groynes. Their role is to break the waves and thus protect the beaches. These groins have caused an effect that is one of the particularities of Les Moutiers: at the end of these wooden braids, the ocean has rolled out a long carpet of blue mud. Another effect of this "fattening" of the beach is the warming of the water as it passes over the sand. Since 2006, an action of reasoned cleaning of the natural beaches is engaged on the site Natura 2000. The beaches are cleaned manually during the summer season, in order to preserve the fauna and flora. The cleaning with the help of mechanical machines is forbidden on the whole commune. Thus the biodiversity is respected.