Caves of South Wales Dragon

Ogof Clogwyn

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Ogof Clogwyn is a short but easily accessible cave in the Clydach Gorge that exhibits some fine examples of phreatic shelving in the main stream passage.
Length 352m
Altitude 235m
Grid SO 21299 12388
The stream cascades down from the large obvious entrance forming a small waterfall. This obvious and easily accessisble cave has long been known. The first documented exploration was by the SWCC in 1951. The sump has been explored for 40m to a depth of 5m. A dive by Duncan Price in 1996 found the flow to emerge from beneath a rock flake at the base of a gravel slope.
The cave is located in the side of the South side of the Clydach Gorge 400m upstream from the Devil's Bridge. The safest approach to the cave is from the South side of the gorge. After crossing the Devil's Bridge the footpath can be followed up the side of a steep sided tributary to the Gorge to reach a old tramroad at the top. Following this to the right and passing some disused tunnels on the left, a building is reached on the right. A footpath beside the building descends into the gorge with a steep section near the end before it leads to the cave entrance.
Clydach Gorge Google map showing the location of Ogof Clogwyn and other caves in the area.
Location map - click marker to show entrance photo
No known access restrictions.
Ogof Clogwyn is an interesting and easy cave that is popular with novices and outdoor centres. A small waterfall cascades out of the main entrance 1.5m up in the cliff face. The cave consists predominantly of a single stream passage with some fine phreatic shelving that leads to a low silted sump. On entering the cave the stream can be followed as the passage meanders. Several small passages can be seen on the right which either are oxbows or lead to smaller entrances in the cliff face overlooking the gorge. In the main passage on a pronounced right hand bend is a pile of boulders in the floor that can be climbed to access a high level passage above. This is the High Level Series that starts as a crawl and leads over a series of traverses ahead, a too tight rift leads to daylight before veering right and reaching a small chamber close to the entrance passage. At the start of the traverse a low crawl on the left leads to a passage that emerges in the roof of the passage near the entrance.
Back in the main passage heading upstream the roof height eventually lowers until the main sump is reached. Just before the main sump is reached a low passage on the right leads to a second smaller sump.
No tackle is required in the cave.
If approaching the cave from the South side of the Clydach Gorge a handline can be rigged from the anchor points on the steep descent to the river level and cave.
Cambrian Cave Registry for Ogof Clogwyn
UK Caving Wiki entry for Ogof Clogwyn
Caves of South Wales | Tim Stratford | ISBN: 1-871890-03-9 | Published by Cordee
Selected Caves of Britain and Ireland | Des Marshall - Donald Rust | ISBN: 1-871890-43-8 | Cordee
The Caves of Clydach | Tony Oldham
A Caver's View of the Clydach River | Theo Schuurmans | Cwmbran Caving Club
An Exploration Journal of Llangattwg Mountain | Chelsea Spelaeological Society Records V19 - 1992
Welsh Sump Index | Welsh Section CDG
Care should be taken if crossing the river to access the cave, and avoided in high water conditions
Belay points are installed beside the steep footpath down to the cave on the South side of the gorge. This will allow protection to be rigged to protect novices on the descent.
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.
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