Water End Swallow Holes is a biological

site of Special Scientific Interest A Site of Special Scientific Interest (SSSI) in Great Britain or an Area of Special Scientific Interest (ASSI) in the Isle of Man and Northern Ireland is a conservation designation denoting a protected area in the United Kingdom and Isle of ...

Hertfordshire Hertfordshire ( or ; often abbreviated Herts) is one of the home counties in southern England. It borders Bedfordshire and Cambridgeshire to the north, Essex to the east, Greater London to the south, and Buckinghamshire to the west. For govern ...

, south-east England. Located in

Welham Green Welham Green is a village in the parish of North Mymms, Hertfordshire, England. It is situated a mile to the west of the Great North Road coaching route that used to run through the neighbouring hamlet of Bell Bar from London to York and the n ...

and under the planning authority of Welwyn Hatfield District Council, it has an area of . The site covers more than fifteen swallet holes, the only ones in

chalk Chalk is a soft, white, porous, sedimentary carbonate rock. It is a form of limestone composed of the mineral calcite and originally formed deep under the sea by the compression of microscopic plankton that had settled to the sea floor. 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 ''Glyceria maxima'' (syn. ''G. aquatica'' (L.) Wahlenb.; ''G. spectabilis'' Mert. & W.D.J. Koch; ''Molinia maxima'' Hartm.; ''Poa aquatica'' L.), commonly known as great manna grass, reed mannagrass, reed sweet-grass, and greater sweet-grass is a ...

. The site also has areas of woodland and grassland. From the sinkholes the waters become the River Colne. There is access to the site from Station Road.

References

Water End Swallow Holes Water End Swallow Holes Welwyn Hatfield {{hertfordshire-geo-stub

See also

References