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Cheddar River Cave


ST 468.540

by Richard Stevenson

The three most obvious sites for gaining entrance to the main river cave are Skeleton Pit in Gough’s Cave entrance, Sayes Hole and the actual risings.  The first recorded dives were in May 1955 and in the cases of Skeleton Pit and the Cheddar Risings no material progress has been made since those original dives.


21.5.55 R.E.DAVIES

Using an aqualung, the diver reached a depth of 74 ft. at which point the rift became too narrow for further progress; size 20" by 4ft.  No side passages were observed in the poor visibility but possibilities were thought to exist at a higher level.

CDG Rev, 6 (1953/5)
WCC Jnl.(51), 17 (1955)

First Feeder


The divers explored under the arch and found many small holes; the biggest was about 5 ft deep and would admit a body, but at its lowest point would only just admit a pair of feet.  No progress was made.

CDG REV, 6 (1953/5)
WCC Jnl.(51), 17 (1955)

None of the other risings are of any interest to the group, being all too tight to dive.

Conclusion. Many tons of rock would have to be removed from the First Feeder before any progress can be made.

The first dive in Sayes Hole on 31st May 1955 by J S Buxton terminated at a slot in the floor at 25-30 ft depth and 40 ft from base.  This slot was passed by Messrs Drew, Savage and Woodlng in the autumn of 1965, who emerged in the main river.  Upstream this passage was reported blocked at 150 ft by boulder chokes and downstream becomes impenetrable after 40 ft.

Subsequent dives have reported the upstream distance to be approximately 70ft and no further progress has been made.

During late 1985 Mike Duck and I expended considerable effort digging into the second rising where we passed a very tight squeeze and dropped into a small underwater chamber with a flow of water.  The way upstream is very tight and may be blocked with boulders.

The first Somerset Sump Index produced by Ray Mansfield in April 1964 contained the following introduction to Gough’s Cave.

This cave contains three sumps, all of which fall into the class that has been called Reservoir.  Of these three water surfaces only the so called 'Skeleton Pit' is large enough to dive.  The level of all three sumps is approximately the same, and like that of Saye's Hole, they rise when, in times of flood, the resurgences become over laden. At such times water rises within the cave from gravel in the floor of the passage at its lowest point; considerable flooding of the cave then occurs.

Andy Sparrow suggested to me, in his own inimitable way, that I might like to have a look at the sump in the oxbows.  It was getting near to closing time, I was in no fit state to argue and it seemed like a good idea at the time!  The dive was fixed for the following Monday evening.  I looked back at my old newsletters, and found a log for the site which did little for my enthusiasm.


ST 467.539

18th May 1980

Diver: M.J. Farr

Aim: to examine the recently discovered sump about 200m from the entrance.

The sump pool is approached via a narrow (1.5 x 0.75 m.) pot, ten metres deep.  In clear water the sump (0.75 m. in diam) appeared to level off into a larger passage after a couple of metres.

On diving, feet first, any horizontal development was ruled out.  The pot continued on down over a small ledge.  Visibility nil.  The passage dimensions together with excessive sediment left a lot to be desired, and at -10m. the diver was concerned as to the position of his line, plus the fact that his valve was not performing satisfactorily.  The pot continued.  Little difficulty was experienced on the ascent and a further dive using a large cylinder could well be a good idea.

Monday evening came (11th November) and I set off with Quackers and an ebullient Sparrow.  The approach had all the makings of a Sparrow delight, awkward and very muddy.  The descent to the sump is a fairly difficult climb with loose rocks on the ledges.  We took a rope to assist on the climb and I dived on a single set of kit using the end of the rope as base fed diving line. I descended 45ft in totally zero visibility in a tight pot to bottom on a mud bank.  There was an impression of a void on my left but I had run out of rope and was unwilling to drag it sideways with such a difficult descent.  I returned to the surface with only moderate difficulty.

A return dive was made a week later with a line reel and lead weight.  In view of the restricted nature of the sump and its approach coupled with a desire not to be overly optimistic I dived on a single set without fins.  The descent was accomplished without problem (other than it feels about a hundred feet deep) and the line belayed to the lead weight on the mud bank.  A traverse of about ten feet to the left resulted in a noticeable temperature drop and I emerged into a large river passage of crystal clear water with visibility of approximately twenty feet.  What a contrast from the tube I had descended, and what a fool I felt without fins or a second set of diving equipment.

Diving was out of the question from mid December until early February as a result of flooding.

Subsequent dives in the company of Rob Harper have resulted in 500 ft. magnificent river passage terminating in a chamber.  The chamber, which has no dry land, crosses the main river and is approximately one hundred feet long, forty feet high and fifteen feet wide.  The chamber has been called "Lloyd Hall", I know Oliver would have been very excited about these discoveries and it seems a pity that he died such a short time before.

Rob Palmer and I have continued exploration from Lloyd Hall.  A steeply descending drop through boulders to 40ft and difficult route finding lead in about 100ft to a wide bedding with a scalloped floor.  A further 100ft of awkward passage with huge deep cross rifts and rock bridges finally yielded a magnificent sandy floored ascending passage maybe 20ft wide.  This ascended up the bedding to break surface on a small sandy beach some 350ft from Lloyd Hall.  Two very small airbells were found and, in view of Martin and Sue Bishop's wedding, were named "Wedding Bells".  A climb over boulders from the beach led into a large chamber, the " Bishops Palace" which is approximately 400ft long, 80ft wide and 40ft high.  Carrying diving torches and wearing only wet sock boats we explored the chamber, climbing over loose rocks the size of small caravans, to eventually find the continuation of the river passage - a beautiful green sump pool in a rift.  It is hoped that we can put three divers in this pool in the very near future and actually film line laying  as it happens!  Some photographs and a survey should be available for the next issue together with any further news.

One of the more unfortunate aspects of underwater cave exploration 1is the effect it has on the cave environment.  Little blind white wriggling things can cope quite well with rising flood waters (they simply hide), but a sudden careless fin stroke, an unexpected stream of air bubbles across the roof, a silt-ploughing diver, all do them no good whatsoever.  Its not publicity that hurts caves, it's cavers, and there is great responsibility in exploration.  Already, in exploring the Cheddar River, we have noticed how many little animals are getting dislodged from their perches, and washed down the cave, simply by dint of our passage. Many of these may not re-establish themselves before being washed out through the resurgence.

So, there are a few guidelines we are using, to coin a pun.  The lines themselves are being laid along the left hand wall, tautly, to avoid divers straying off a given path.  Except for check-out examination on exploration dives, the other side of the passage is 'verboten'.  The concept of taped off sections is being applied for the first time in underwater cave exploration in UK (and possibly in the world).  Once the entrance is large enough, we hope that any divers who have the opportunity to dive here will use some form of buoyancy compensation, there is no need to snowplough through sediments, not only is it bad for conservation but it is simply bad technique.  Short of using re-breathers, which eliminate the bubbles, there is little else we can do at the moment, but at least the bubbles are being restricted to one side of the passage, leaving the real cave divers undisturbed in the rest. It would be nice to see this practice adopted elsewhere as a matter of course.  The wildlife in sumps is by no means obvious, and so far little notice has been taken by cave divers of the small creatures that share the water with them. At least this is being remedied at Cheddar.

The Cheddar River has proved extremely interesting in terms of cave biology. The populations of all the creatures mentioned above are high, and it could be that the phreatic zone is a lot more important than has hitherto been thought.

A preliminary collection has recorded three invertebrate species, each worthy of note.  Gammarus pulex,  a troglophilic amphipod appears in the cave, unusually lacking in pigmentation.  Many Gammarus in caves have started their life in surface and been washed underground, after daylight has had a chance to trigger pigmentation.  The Cheddar specimen has obviously spent its entire life underground.

A white flatworm, Dendrocoleum lacteum, is an unusual troglophile.  Its habitat is more usually in shallow, eutrophic, sluggish waters on the surface, quite the opposite to rock-floored underground river passages. It has been recorded elsewhere in the Mendip underworld, and is probably there because the food is good. Dendrocoleum munches its way through a troglobitic isopod, the only true cave animal so far recorded in the sump. This tiny isopod, Procellus cavitatus, is common enough in Welsh caves, but the Cheddar ones are comparative giants.  Almost half as big again as their Welsh cousins.  The Cheddar Procellus helps keep the cave clean, feeding on organic refuse swept down on the cave waters, and may well be partly responsible for the clean-up of many of the pollution events which have affected the system in the past, such as the discharge of slaughterhouse wastes into Longwood in the late 1970's, which made Longwood very unpleasant for a while, but which had no effect on the waters at the risings.  Procellus falls victim to the sticky trail left by the flatworms, which on retracing their wriggling way, make passing meals of the luckless isopods, who simply stick around waiting to be eaten.

I should like to thank Sandra Lee and Chris Bradshaw for their eager support, all the staff and cavers for the invaluable assistance they have given in portering equipment and making the approach somewhat less objectionable, and Quackers for his tireless efforts as dive controller.  The information on the wildlife and the survey were kindly supplied by Rob Palmer.