The Zwin originated around the beginning of our era, when as a result of a rise in sea level breakthroughs occurred in the dunes along the North Sea coast. As a result of these breakthroughs are scoured deep trenches in the hinterland of. The at that time arising Zwingeul expanded considerably in the twelfth century, when there occurred back major floods. In the hinterland created a ramified channel system, making cities like Damme and Bruges are accessible to shipping.
Pretty soon, however, began to silt up the channels, and despite all measures the navigability of the Zwin became less and less. The siltation also brought a considerable advantage with it. Increasing share of the Zwin could be reclaimed. The embankments were favored by the dunes at Knokke proliferated in an easterly direction, so that eventually could take place in the estuary embankments.
The estuary is 200 hectares remaining hoarse. This bark is on the seaward side bordered by a row of dunes, and on the landward side by the International embankment built in 1872. The Zwingeul enters the field through an opening in the dunes. Directly behind the trench mouth are sandy beach plains, passing farther inland lake silty marshes.
The salt marshes are important as a nesting area for birds. In addition to a large colony of gulls as a breeding bird i.a. to see redshank, avocet and oystercatcher. From the seawall, the little egret observe almost daily during his search for food in the flood left behind after urination. The bark is a lot of sea lavender.