Caves of South Wales Dragon

Cwm Dwr Two

↓ Further information

Despite it's close proximity to the South Wales Caving Club this a little visited active stream cave that provides a quite interesting trip.
Length 370m
Altitude 330m
Grid SN 85720 15627
The cave was first discovered in 1938 and then rediscovered in 1990 and extended by the SWCC.
Cwm Dwr 2 is located in the centre off the same disused quarry as Cwm Dwr Cave beside the Headquarters of the South Wales Caving Club. The entrance is gated for safety reasons, the key being kept at the adjacent SWCC Headquarters.
Swansea Valley Google map showing the location of Cwm Dwr Two and other caves in the area.
Location map - click marker to show entrance photo
There is a locked lid on the entrance shaft in the quarry. A key is available from the South Wales Caving Club.
The entrance is in the floor of the Cwm Dwr quarry just past the Cwm Dwr entrance to OFD. The entrance is protected with a locked lid that opens onto the top of a 6m deep shaft into a small chamber. A fixed steel ladder drops you into the rubble floored chamber where a descending rift passage leads off. The rift passage is well scalloped and there are areas of nice calcite flows on some of the walls. Beyond a dam the passage reduces in height to a crawl and stoop to reach a pool that was once a short sump named Helen's Horror. This sump had some modification made to it in 2010 and now is a short wet crawl.
Beyond the wet section the passage continues for a short distance as a sand and gravel floored crawl that leads to a T junction with a small stream issuing from the right. Upstream to the right leads to Ping Pong Passage named after the ping pong balls that were dropped down a borehole that was used to locate the cave in 1990. Ping Pong passage can be followed for about 60 metres to reach a choked area with boulder fill ahead and to the right. Back at the Junction the way on is to follow the water in the passage to the left which gains height as you approach the head of the pitch. Two anchors of unknown age in the right hand wall allow the pitch to be descended. A 10m ladder drops you just short of the floor of Default Chamber to land on a pile of rocks that allows easy access to the lower rungs of the ladder. At the bottom of the pitch the boulder floor of the chamber rises to the right to reach a 20 metre long sandy passage that ends at a perched sump that can be syphoned off in about three hours. The way on is to follow the flow of the water at the lower end of Default Chamber. A narrow streamway is followed, to start with at stream level, but after about 50m you will need to traverse until after about another 100m you can drop back into the stream. The passage continues to meander for another 100m with the passage height reducing until eventually you are wading in water as the roof drops to meet the sump. This sump feeds the first stream inlet to Cwm Dwr Jama.
Pitch into Default Chamber 11m
Cambrian Cave Registry for Cwm Dwr Two
Descent 100 Article p38-40 on Cwm Dwr II Rediscovery | Malcolm Herbert - Helen Langford
Caves of South Wales | Tim Stratford | ISBN: 1-871890-03-9 | Published by Cordee
A small stream feeds the duck in the entrance series. In wet weather this will fill the pool faster than it can be syphoned.
The photographs and information of this page has been provided to help cavers planning trips. Caving can be a dangerous activity, if you are interested in exploring caves please join a caving club so you can enjoy a safe introduction to this sport. Local caving clubs are listed on the links page or you can visit the 'New To Caving' website for more options.
If you feel that any of the information is incorrect or should be updated please contact us.