An old dam across the Couesnon River in front of the mount protected agriculture and nearby town Pontorson from floods, but had also stopped the river's vigorous outflow during low tide that had flushed sediment out into the bay and for centuries helped Mont-Saint-Michel remain an island during high tide.
Gradually, the island was turning into a rocky hill in the sand, surrounded by water only during spring tides a few times a year and connected to the mainland with a causeway that further slowed the water's flow and served as an unsightly parking lot.
"In order to transmit, one must preserve, but for decades Mont-Saint-Michel threatened to silt up completely, which would have realised the old dream of English generals, to take the mount as if it was a hilltop amid fields," Macron said during a visit to celebrate the monument's 1,000th anniversary.
Macron said a new hydraulic dam project started in 1995 and completed in 2015 was now proving it is able to gradually flush sand out of the bay.
"In just a few years, the silting up of the bay has been stopped and we have restored the possibility of an island," Macron said.
In recent years, the parking lot has been moved inland, and visitors can now access the site only with shuttle buses, on foot or by bicycle via a new bridge on stilts that lets the water pass under it.
A UNESCO world heritage site since 1979, the Mont-Saint-Michel is one of France's top tourist attractions, with nearly 2.8 million visitors in 2022.
(Reporting by Noemi Olive in Mont-Saint-Michel, France; Writing by Geert De Clercq; Editing by Matthew Lewis)
By Noemie Olive
