Ringvaart
Ringvaart is the Dutch name for a canal with a circular course, mostly around a polder .
Ringvaarten were often created in the bank area of the lake, which was then drained. Since most of the Ringvaarten are still used to drain a polder, the water level in them is often higher than the bottom of the enclosed area.
Well-known Ringvaarten are the Ringvaart of the Haarlemmermeer Polder and the Ringvaart of Ghent .
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Commons : Ringvaart - collection of images, videos and audio files