Caves of South Wales Dragon

Ogof Rhyd Sych

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Ogof Rhyd Sych is a little visited cave with a fearsome reputation built on the tight, low, wet and arduous passages that you need to pass on the route into the cave. Beyond this however the cave suddenly changes character to reveal 500m of the finest river cave passage in the UK. A fine reward for those thin cavers determined enough to make a visit.
Length 1097m
Altitude 280m
Grid SO 04152 10221
The cave was first investigated by SWCC in 1950, with dye tests of the water from Ogof Y Ci shown to resurge at Ogof Rhyd Sych. The cave was extended by the British Nylon Spinners Sports and Social Club in 1957 and again by Cwmbran Caving Club in 1967.
Ogof Rhyd Sych is located in the very beautiful Nant Y Glais gorge, the waters of the Nant Y Glais stream cascade gently down a short waterfall that emerges from the stunning entrance to this cave. The cave is best approached from a car park overlooking the Taf Fechan on the road that forks off from the Aberglais Inn. Following the road across the Taf Fechan and then down to the bridge over the Nant Y Glais stream you can follow the footpath on the right hand bank of the stream. After about 400 metres the stream issues from a small gorge, this can be followed upstream after which the stream will be seen issuing down the small waterfall from the entrance to the cave. Alternatively from the start of the gorge you can head upwards to find a footpath following a fence along the top of the gorge. At the end of this fence is a stile that can be crossed to leave you at the top of a dry waterfall in the river bed below which the water of the Nant Y Glais stream can be seen cascading out of the cave entrance.
Central Northern Outcrop Google map showing the location of Ogof Rhyd Sych and other caves in the area.
Location map - click marker to show entrance photo
No known access restrictions.
The first 20m are a fine stream passage through calcite veined limestone until the passage abruptly changes character at a duck that will sump in moderately wet weather. Following the guide rope through the duck a small muddy chamber is found beyond, from which a squeeze down a hole leads into a crawl across a mud covered bedding plane. This reaches a larger sloping cross passage that should be crossed to reach a continuation of the bedding plane on the opposite side. This second bedding plane is accessed via a squeeze down over a calcite flow and then crawl through a pool of water. At the end of this bedding plane a second cross passage is reached with some fine gour pools and calcite flows in the floor of the passage. The way on is to enter the next bedding plane opposite the exit of the previous bedding plane. This bedding plane is very, very tight, the route across to the sound of water is taken by snaking through the only section that is big enough to allow you passage. Reaching the stream you head up slope against the flow of water in the bedding plane until you reach a small slot between boulders where the water emerges from. A short section of walking passage is followed that becomes a tighter and more rifty. This leads to the base of a tall cascade that is easily climbed. At the top of this cascade the the passage is a very tight rift, with a smaller cascade that is difficult to pass either by squeezing at stream level or via a tight traverse at a higher level. A second cascade is then met, which once climbed leads to a short low section and then a passage with deeper water. This stream continues for a short distance until a cascade is met on the right issuing from a bedding plane above. If the cave was not bad enough before, now in this bedding plane you have to crawl flat out over a floor of spiked rock, painful on the knees and it destroys your wetsuit as you go. After this bedding plane is crossed a more pleasant wide and low stream passage is encountered that can be followed becoming wider and lower as you go. On the left a climb up calcited boulders leads into a short taped section of fine formations. A hole in the floor leads back to the low stream for another section of crawling past calcite formations on the left until this breaks out into the magnificent First River Chamber. This is one of the finest decorated sections of stream passage you are likely to encounter in the UK. After a hundred metres or so, a climb through formations above the stream leads to a large passage with a scramble over boulders. This passage can be followed by climbing up and over the boulders with occasional descents to the river passage until eventually you find yourself on a calcite balcony overlooking the large and well decorated Second River Chamber. A climb down to the right drops you into this final section of impressive streamway where the cave ends as a large boulder choke believed to the the other side of Ogof Robin Goch.
A wetsuit is essential for this trip.
Ogof Rhyd Sych Video
Cambrian Cave Registry for Ogof Rhyd Sych
UK Caving Wiki Entry for Ogof Rhyd Sych
Caves of South Wales | Tim Stratford | ISBN: 1-871890-03-9 | Published by Cordee
The Caves of the Central Northern Outcrop | Tony Oldham
This cave should only be visited in dry settled weather as it rapidly floods following rain.
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.