It consists of 1600ha of marshland reclaimed from the sea (called a Koog in German) and protected with a dike in 1696 to secure the land connection between Büsum and Wesselburen.
It encompasses 1600ha of coastal wetland that has been redeveloped (a Koog in German) and is shielded by a dike built in 1696 to connect the communities of Büsum and Wesselburen.