It remained as a sandbank until the Christmas flood of 1717. After this flood the island Bosch was completely washed away by the sea.
It was always known that the island of Bosch once existed. Many maps showed it's presence. The Sunken History Foundation was founded after a pilot project about the island bosch in 2005/2006. In 2008 the geologists Karel de Vries and Albert Oost of the Sunken History Foundation, found the first real evidence of it's location. By using ground-radar they found at a depth of 3 meters different ground deposits. Because of the islands movement, Schiermonnikoog now lies above the former island Bosch.
The movement of the Wadden Islands
The Wadden Islands are constantly moving. The most important movement is called "walking": the islands are moving from East to West. Due to this process, islands disappear slowly into the ocean in the West, while large sandbanks appear on the East. This so called "walking" is also the main reason why al the islands towns locate themselves on the West side of the island. But when these towns were founded, they usually lay in the middle of the island. Due to this, many towns and villages disappeared into the sea during the last centuries.
- Wikipedia - Wikipedia on Bosch (Dutch)
Sunken History Foundation - Website of the Sunken History Foundation (Dutch/English/German).
Wikipedia - Wikipedia about the Wadden Islands (English).
- A. Buursma & H. Feenstra (red.), 2006. Bosch, eiland in de nevelen van de historie. In: Themanummer "Bosch boven water gehaald", Stad & Lande 15, nr 2: p. 4-33.