WHEELS ALONG THE WEST FRISIAN SEAWALL

Dike breaches usually occur at weak spots in the dike that can occur due to poor maintenance or seepage. Seepage (discharge of groundwater at the earth's surface) is caused by an underground flow of water from a higher to a lower area. If the water then seeps under a dike, dike material can be washed away. In the event of dike breaches, the water churns with great force into the land behind, creating deep gullies (wheels or welen). Due to the depth of the wheel, the dike can no longer be repaired in the same place. Because the new part of the dike has been built around the wheel, the West Frisian Sea dike has gradually taken on a winding course. The twists and turns in the dike often refer to old dike breaches.
When the dike is repaired on the sea side, the wheel is diked inside. Inner dike wheels (figure 1)) are visible in the landscape as small deep pools around which the dike winds.
When the dike is repaired on the land side, the wheel is diked outside. Outside dike wheels (figure 2)) that have been filled with material deposited by the sea (so-called dry wheels), are recognizable as winding in the dike.

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