Zwin creek remnants and Passageule

About 2,600 years ago, the coastal barrier created by the decrease in the rate of sea level rise was broken. A decreasing surface area and the scouring action of the tidal channels created several islands in the area, but these often lasted only a few centuries due to tidal dynamics. Medieval embankments played a major role in the development of the creek and gully area. Before the embankments, tidal action naturally caused the land surface to rise above the high tide due to the siltation of salt marshes. As a result, the land was high enough to live on and was mostly used for sheep farming. From various settlement centers, earthen berms and low dikes were constructed on the salt marshes as a preventive measure to counter extreme high water. But this also caused water to rush up against the dikes and sometimes even through dike breaches. In addition, it also caused silted up channels because the sand brought in during low tide could no longer leave the tidal channel.

During the Eighty Years' War (1568-1648), the Zwin region was in the front line between the Northern (State) Netherlands and the Southern (Spanish) Netherlands. The Zwin dikes southwest and east of Sluis were breached in 1583. The sea penetrated the polders and scoured out several new gully systems. Their mostly rectilinear course indicates that the incoming water largely followed the existing dug waterways. In 1611, part of the flooded area was reclaimed. After the Twelve Year Truce, however, the dikes were breached again. A large area became marshy and uninhabitable. fortifications by both Spanish and State troops and important fortifications were constructed. By 1700, almost all of the inundated area had been reclaimed and only the Zwin estuary with connecting tidal channels remained open. Large parts of the former main course of the Zwin were reclaimed in the 19th century and navigability in the area was increased by the construction of new canals. This put a definitive end to the large tidal channel of the Zwin. Only the creek remnants remained visible in the landscape as dammed, water-filled beds.