Since 1858, a technique has made it possible to advance on the Baie du Mont-Saint-Michel. The Couesnon estuary was drained by diverting the river, and the lands were transformed into salt marshes (schorres). Once colonized by vegetation, a dyke protects them from the tides, and their carbonate-rich soil becomes suitable for agriculture. Such technique differs from that practiced in the Netherlands, which consists in damming and pumping salter water. Today, the bay is home to 7,660 acres (3,100 ha) of cultivated polders protected, maintained, and promoted by the Conservatoire du Littoral (Coastal Protection Agency).