The two lakes lie in glacial hollows separated by a narrow neck of land which contains a mound which is a Norman motte. A narrow canal allows water to flow from the upper lake to the lower, and allows the movement of fish and eels. The lower, northern lake extends for some 27 acres and exhibits a complete vegetational sequence from open water, through reedswamp to Alder and Willow carr. The lake is  ideal for overwintering wildfowl, breeding ducks, grebes and swans.

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