Team: Tarquin Wilton-Jones, Morgan Specht, Dave Coulson. Warden: Mike Kushy
Another of those caves on my wishlist, Reservoir Hole had traditionally had access problems, but access is now possible with a formal warden system. Once again, the trip was set up by our club meets secretary. With a last minute substitution of warden, a change from morning to evening, and three separate changes in team members, it really does help to have someone patiently taking care of the arrangements.
Dave, Mike, Tarquin and Morgan at the entrance - picture by Morgan Located below the tallest cliffs of the Cheddar Gorge in Mendip, its presence had first been suspected when the construction of a small covered reservoir was plagued by water sinking through its walls. A draughting hole at the foot of the cliffs above the reservoir was the start of an extremely long digging project, which eventually uncovered a streamway, enormous rift passages aligned on a series of faults, and then finally the crowning glory of one of the largest chambers in Britain, adorned with spectacular formations.
This was to be my first attempt at cave photography in over 9 years, and by far the largest underground space I have ever tried to photograph. Definitely a little rusty. My two flashguns were rated for 30 metre and 15 metre use, which would not be enough for a chamber that size, but Morgan had the foresight to bring a second 15 metre flashgun. With two slave units, it should have been possible to take the pictures on bulb setting and manual firing of the first flashgun. However, one of the slave units consistently failed to operate, so we resorted to using manual firing of two of the flashguns. Without a tripod, shaky hands and slight timing differences between flash firings meant that there might be some unexpected duplication and ghosting in certain areas, but this is a limitation we would have to live with - it only affects a single picture. Unless otherwise stated, camera, setups and edits by Tarquin, flash and modelling by Morgan, Dave and Mike.
The trip began at dinner time on a bank holiday weekend, competing with the droves of sightseers for parking space. We handed over our signed liability waivers and access fees, and headed into an oddly placed hole above the reservoir - the hole which must once have been a sink taking water from the gorge before the gorge was cut deeper below it. Surrounded by a host of cave spiders, their eggsacs and shed skins, and a single sleeping lesser horseshoe bat who seemed not to know what time of year it was.
Dave at the Main Dig spiral staircase, flash by Mike and Morgan The sloping little passage soon reached the Stanton's Drive dig, and the beginning of the finest example of underground engineering that Britain has to offer. The boulder choke had been neatly rearranged into a perfect dry stone wall, leading into Moonmilk Chamber, whose walls were covered in a thick coating of soft, white moonmilk, with a pristine bobbled surface texture. In the floor, the Main Dig began, following a seemingly insane path downwards through a boulder choke for a depth of some 45 metres. Step after step, climb after climb, all neatly arranged into dry stone walls, and perfect spiral staircases of rocks. Mostly with no scaffolding or shoring (though one section had a few sleepers). Every bit as impressive as the final chamber.
Dave in the Grand Gallery, flash by Morgan 
Dave with the Three Wise Men formation in Topless Aven, flash by Morgan and Tarquin
A tiny inlet brought a sudden change in character, as the cave broke into a large phreatic tube; Grand Gallery. This short-lived spectacle ended at the climb into Topless Aven, the first immense rift soaring some 30 metres up into the darkness. A handline served to deter cavers from accidentally touching the formations. From here, the route split, with the original digger trying ahead into Hard Times, then giving up and trying upwards instead, eventually finding Golgotha rift. The most impressive extensions were then found by retrying at the end of Hard Times, with the original digger sadly missing out on the major breakthrough which had been so well earned. In order to avoid tracking mud into the decorated parts of the system, we went ahead first, through the Hard Times crawl, and into Resurection, another immense aven lying on the original fault. A ladder climb part way up the rift gave access to a balcony where a double ladder pitch dropped into an immense fault rift.
Resurection 
Columns in the Frozen Deep This is the beginning of the Frozen Deep, the largest chamber in Britain by surface area at 2981 square metres, but second by volume at 39328 cubic metres (after Gaping Gill's Main Chamber). Ahead, the far point of the chamber was some 79 metres away, with calcite flows decorating almost every part of the rift walls, and a superb grotto in the rift ahead. Morgan set up the ladders and lifelines, and we took our turns to enter the vast space. As we dropped into the rift, it became apparent that this was just one end of the chamber. To the right, a 40 metre wide archway adorned with two stupendous stal colums and a lengthy stalactite, gave access to the vast open space of the chamber, disappearing for 71 metres into the darkness. This was no ordinary space, and lighting it would certainly be a challenge.
Towards the grotto, note the vertical scratches at the left edge 
The grotto, flash by Mike and Morgan
We started by heading towards the grotto, passing a stal slope climbing 30 metres up the wall, topped with a giant stalactite. The grotto itself was quite stunning, though in order to preserve the floor, the only possible viewpoint is a little obscured, and it is hard to photograph, with no way to provide a sense of scale. It is definitely best seen in person rather than in a picture. Scratches on the overhanging fault wall from falling boulders at first seemed to make no sense, until they were explained as the scratch from a boulder slowly descending on the surface of a melting ice plug, constantly being pushed into the wall by the ice. Something none of us had seen anywhere else before. The dustings of mud on the rocks all over the chamber were revealed to have a similar origin, essentially the moraines from the underground glacier, which filled the space that must have existed for eons before the last ice age.
Morgan and Mike in the first quarter of the Frozen Deep 
The phreatic two thirds of Frozen Deep Heading through the archway into the other three quarters of the chamber, the size could be really appreciated. The stal became less prominent, though still admirable. The paths climbed down little ladders and created a looping route through the phreatic arches, where the oversized scallops on the walls showed that this colossal chamber was an active phreas in its largely original state, and not the result of a collapse. At the far end of the chamber, a hole in the floor dropped to the lowest point of the cave, which we avoided because of its mud. Up in the ceiling, some 52 metres above, avens accessed a series of roof passages, climbing high up to separate tops, including the highest point in the cave. On the right at the end of the chamber is the ascent into High Country, whose passage ends very close to the floor of the gorge, apparently close enough to hear the traffic. We avoided this so that we would not bring its mud back into the chamber. It would have needed SRT kit to do the roof passages anyway.
 |
| The bottom half of Golgotha |
Tarquin with skull-shaped stal in Herbert's Attic - camera and setup by Morgan, lighting by Dave, edits by Tarquin
At Topless Aven, we climbed up another set of grand dry stone walls, rising 25 metres through a boulder choke. No scaffolding, no cement. Just dry stone walls, vertically climbing through a boulder choke. Crazy. Suddenly another change, and we were in Golgotha rift, the old main destination of the cave, and truly impressive in its own right. It climbed far into the distance above us, becoming steeper and steeper. We left the main camera at the bottom, and climbed up the roped climb through the hole far above us. This led to another rope climb, followed by a ladder and another rope ascent leading over an enormous boulder. At last we could see the muddy roof, where a final climb through a hole reached a dry-stone walled walkway, ending at a dig - Herbert's Attic - and one of the highest points in the cave. A large stalagmite is supposed to look like a skull (the reason for the name of the rift), where Morgan's compact camera took over from my DSLR.
The return through the boulders seemed a waste of height, since we would have to drop 90 metres back to one of the lowest parts of the cave just to re-ascend over 65 metres through the entrance chokes. The bats appeared at Topless Aven, flying around us as we made our way through the cave. At the bottom of the Main Dig choke, the sounds of the bats flying through narrow tubes created a very odd effect, combined with a strange roaring noise that sounded more like a collapsing choke. Once we emerged from the cave, these sounds were identified as the engines of the cars racing up and down the gorge, some 20 metres above where we had been standing. Clearly the cave had more surface connections than were currently known.
This really was a fascinating and very beautiful cave. Not just for the huge size of the chamber, and not just for the stal, but for the fault controlled rifts, the phreatic tubes, and the underground glacial moraines of the Frozen Deep. It is possible that the chamber may at some point have a route created for tourists, so that it can become another show cave like the others in the gorge. But the original entrance has its own attraction for cavers; the engineering has to be seen to be believed.
Thanks to Morgan and Dave for the company, to Mike for showing us around this awesome cave at such short notice, to all for making the pictures possible, and of course, a massive thanks to Claire for arranging yet another excellent trip.
Trip report: Tarquin Wilton-Jones
