Kolk lakes Zuid-Beveland

This geosite consists of a cluster of several scattered lakes in the landscape of Zuid-Beveland. The lakes were originally gully holes formed as a result of a dike breach. They lie directly in front of or behind the dike and are about 100 meters in diameter. Such kolkholes are called "welen" or "wielen". In the 13th century, central Zeeland consisted of a series of islands with a vast tidal area between Walcheren and Zuid-Beveland consisting of salt marshes, mud flats, gullies and slabs. At the site of the geosite, two tidal channels ran from north to south. In between were large sandbars and some salt marshes: Heinkenszand and Ovezande. Where the channels met in the south and curved off to the east, they merged into one large channel that connected to the Western Scheldt: the Zwake.

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Bochten in dijken door dijkdoorbraken, Welen Zuid-Beveland

Reclamation

The reclamation of the region began in the 13th century. In the year 1441, between the Schenge and the Zwake, about 1530 ha of salt marsh had been diked. Halfway through the 15th century the connection of De Zwake with the Western Scheldt was also closed. Poldering of the tidal area west of the Looyve followed only in the following centuries. But this reclamation did not happen without a struggle. Pieces of newly reclaimed land always ended up with their dikes on open water. Weather and tide sometimes caused the sea dikes to break. As a result, the water rushed forcefully into the area behind the dike. Where the dike failed, a gully hole formed: a weel.

Dijken Zak van Zuid-Beveland

Recognizing dike breaches

Most dikes are built in relatively straight lines. But after a dike breach, people usually chose the easiest way to repair the dike: curving around the deep gully hole. Thus, earlier dike breaches can be recognized both by round lakes just behind or in front of the dike, and by erratic bends in the dike itself. A clear example is the Brilletjesdijk northwest of Ovezande. Two of the breaches occurred so close together that the welen now form one eight-shaped lake together. In other places, too, such overlapping welen are called "brilletjes".