Unlike the old Caserne dam, the new dam inaugurated on the Couesnon in 2009 is reversible. It opens to allow the tide to flow up the river and then releases water at ebbing tide. Its action has already made a significant contribution to desilting the bay surrounding Mont-Saint-Michel. The old road dike has been demolished and replaced by an elevated footbridge which allows the sea to flow through. All these works were carried out to give back its maritime character to the Mont. This has now been achieved and one can admire the reflections of the Mont on the bay from the surrounding grasslands.