Water End Swallow Holes

Water End Swallow Holes is an 11.3 hectare (27.9 acre) biological site of Special Scientific Interest in Welham Green in Hertfordshire. The planning authority is Welwyn Hatfield District Council.

The site covers more than fifteen sinkholes, the only ones in chalk which are a permanent feature of the landscape. Next to the holes is a swamp area of willow carr which is biologically important, and in deep water there is Reed Sweet-grass. The site also has areas of woodland and grassland. From the sinkholes the waters become the Colne.

There is access to the site from Station Road.