Zoom in to the Google Map to find the points of interest.
The Devil’s Punchbowl may look like a meteorite impact crater, but it originated as a depression formed by dissolution of Chalk bedrock over thousands of years. The water levels in it are linked to the rise and fall of groundwater. It is one of a local group of ‘Breckland meres’, including nearby Ringmere and Langmere, all designated Sites of Special Scientific Interest (SSSI).
An interpretation panel explains the origins of the Punchbowl.
Chalk bedrock acts as an aquifer, holding massive amounts of groundwater. Chalk is prone to dissolve, particularly in cold climatic periods, so underground cavities may develop and later collapse. These may lead to the appearance of solution holes and depressions (dolines) at the surface. This process is explained on a site panel on the western lip of the Punchbowl. The British Geological Survey map for Thetford (no.174) shows a cluster of dolines in this part of the Brecks.
The Punchbowl is a doline landform. [Image courtesy Natural England]
The beginning of a doline on farmland at Snetterton, Norfolk?
A well-established doline on Ringmere Heath
Water levels in the Devil’s Punchbowl go up and down with the seasons, and often cheat expectations – surprisingly full in summer or unexpectedly dry in winter. The water is linked to levels in the Chalk aquifer; it may be recharged by winter rain, but take several months to trickle through to fill the basin. Have a look at nearly Fowlmere (see map): sometimes there are marked differences in water level between the two lakes, showing that they have separate hydrological systems.
The Punchbowl was almost dry, March 2010. [© Copyright Keith Evans and licensed for reuse under Creative Commons Licence]
Fowlmere. In Victorian times turnips were sometimes grown on the dry lake bed.
The site is marked on Ordnance Survey Explorer map no.229 ‘Thetford Forest in The Brecks’ (c. TL 878 892). There is an informal car park near the road. The Punchbowl is on private land but is viewable from the public footpath. Ringmere and Langmere (part of the Norfolk Wildlife Trust’s East Wretham Heath reserve ) are also worth visiting, some 3 km (2 miles) to the east.