Mud, Mud, Glorious Mud… An Otterly Filthy Trip to the Wye Valley.

Trip date: 17th June 2017

Team: Tarquin Wilton-Jones, Helen Stewart, Dave Coulson, Nigel Jones. Warden: Pete Mason

This cave very quickly made my wishlist when I heard about it over 20 years ago. For various reasons, access had traditionally been quite difficult and the opportunity for a visit never came up. I recently decided to join SWCC after many years with some of the other local clubs, and within a few months, I was on a trip to Otter Hole.

The View Over the Wye Valley

Widely regarded as Britain's best decorated cave, it has a lot to live up to, compared with the likes of Dan-yr-Ogof and Ogof Craig a Ffynnon. Certainly the helictites in Ogof Draenen would be tough to beat. But Otter Hole manages to hold its head above the rest when it comes to the grand, continental-style stal decorations. So much so that it has been designated a SSSI with a warden system controlling access, and making sure that the cave manages to remain in extremely good condition despite the impressive mud encountered on the way in.

The “Clean” Energetic and Enthusiastic Team 

Almost unique, the entrance series is something of an endurance test, beginning with a choke and series of low, muddy crawls, followed by a tidal sump that presents its own timing issues. It opens only during the lowest parts of the tide, so the standard trip times are either the 6 hour racing game - getting in and out during a single low tide - or the 12 hour over-tide trip - going in at low tide, and coming out at the next low tide. The latter allows for longer, more relaxed trips, so this was the option we had selected. The wardens are given a carefully planned set of tide times to work with, taking into account how long it takes the cave to respond to the tide, but even these can be complicated by the timing of the tidal flow within the Wye estuary, and the flow of water in the cave's own river. Many trips are abandoned because of tidal issues, and one friend had tried 5 times before finally getting into the cave. During winter, floods are too frequent, and the entrance series can be partly or completely blocked by flood water or silt for months at a time, so access is restricted to the calmer months.

Formations in The Extensions

Tarquin at Grotto Just After Long Straw Gallery

Of the 5 of us (four plus leader), only Helen and I had caved together before, with most of us meeting in the car park for the first time. Our warden (Pete Mason) appeared in an unwashed oversuit and introduced himself - there's no point in washing kit before a trip into Otter. Sadly, one of our party confused their calendar and failed to appear, but because of the tide times there was no option to delay, and we left the car park only a few minutes after the agreed time.

Hall of Thirty

A lengthy trudge down the valley sides, sweltering in the heat even beneath the trees, brought us to the entrance, located in a cliff just above the tidal banks of the Wye. On our way in, we quickly dropped through the choke into the bedding planes, liberally coated in the tidal mud that gets washed in during floods and high tides. 150 metres later, beauty treatment fully applied, we squirmed our way into the lengthy choke that fills what would have been a larger passage, where an otter had once been encountered some decades before. Giant, elaborate stals were everywhere, but so covered in mud that they were nearly impossible to make out. This would have been a beautiful place before the tidal mud took over.

The mud became deeper and deeper, frequently stealing wellies and hiding the rocks so that each step and climb was a guessing game, until we reached the river, which flowed out of the tidal sump and into an impenetrable rift. From there it makes its own way to the Wye a short distance downstream. Depending on conditions and recent floods, the sump can be a very lengthy sump, a squeeze-sized eyehole requiring a swim and tricky climb, completely blocked with mud, or just a nice, open rift with a sandy floor. It was fully open, and we breathed a sigh of relief; the trip was on. Beyond the sump, the mud became even worse, until a ladder offered a glutinous route up into the top of a tall choke. A rescue dump and rescue phone access point made a small chamber feel safer, but in flood, a high tide can cause the cave's river to fill this section to the roof. The river passage continued beyond in very enjoyable style, with a grand curtain display hinting at the splendour to come, eventually passing through chokes and ending at Sump 2. As we reached this point, the tide would already be rising up and preparing to fill the tidal sump.

Tarquin and Dave at Gour Passage

Several scrubbing brushes tied to a rock indicated that it was time to clean ourselves and each other off in the cold river, to avoid dragging tidal silt into the rest of the cave. The cave is a great example of ongoing conservation. Now the difficult part begins, through Mendipian Way's narrow rifts, squeezes, and lengthy choke. Plastered in regular cave mud, squirming through the choke, and climbing up and down several little climbs, we eventually dropped into a large, fossil passage, and the real cave began.

The formations started almost immediately, with even the first set justifying all of the work required to reach them. But with each corner, the displays surpassed the previous ones. Curtains upon curtains, straws with arrowheads and carrot-bottoms, enormous columns, flowstone, crystal pools, ancient broken stals calcited into new creations. Most immaculately white, and only a small, muddy path leading around their edges. A final turn, and the Hall of Thirty's grandeur outshone everything before it. It is hard for a picture to convey just how much there is to look at. Everywhere had something: giant stalagmites, perfect stalactites, orange, white, flowstones, more stalagmites, and yet more stalagmites. The stalagmites are certainly not as large as their namesakes in the Salle des Treize in the Gouffre Berger, and the giant gour pools were absent, but they made up for it with sheer numbers and variety. This is where the shorter trips end.

The next section of cave had yet more grand stal, but several showed the jet black staining from historical petroleum pollution, the stink of which filled the air in one place, with cavers warned not to touch the toxic byproducts which could cause illnesses. Then the stal vanished as we reached the camp. An inlet was captured in a tarpaulin, with a bad smell and furry growth in the water hinting of an ongoing problem with part-digested sweetcorn pollution. The kind you don't want to drink, but formerly the only water in the cave that was safe to do so.

Gour Passage

Hall of Thirty

Beyond a large chamber and muddy crawl, the stal began again, firstly with smaller decorations, but rapidly filling the passage with yet more continental-style flowstone and abundant curtains. These culminated at the incredible display of Long Straw Gallery, sporting several straws some 4 metres long, and a wall covered in translucent helictites, overshadowed by several immense stal columns and crystal pools. The passage continued through nearly continuous stal, to where gour pools became the dominant formations. Many sported large lily-pad platforms, elevated at several levels above the current water level, and formerly underwater formations similar to those in the famed Lechuguilla Cave. A sudden abrupt end to the formations at the start of an ancient phreas marked the Tunnels junction. Tunnels Right was off-limits to protect the very vulnerable stal (flowstones and a large crystal pool), so we headed towards the far end of Tunnels Left. The formations decided to start again, and although less grand than before, would still have been considered an admirably fine display in any other cave, with several superb grottos. The passage then descended deep into a former sump to reach a small inlet and outlet. The inlet was rather a meagre end to such a grand passage, and its sump marked the end of our route.

Nigel at Tunnels Left

Returning through the stals, while no longer a surprise, was still a magical, unforgettable experience. With the sump now open, the petroleum smell had dispersed within the cave, and we only caught up with it at Mendipian Way. A navigation error nearly took us into the start of Crystal Balls Passage instead, but sadly its pom-pom formations are off limits, and the mistake had to be corrected. We had seen so much stal already that it didn't really hurt to miss a little more. The squeezes in Mendipian Way seemed to have shrunk, but we all made it through to the river, and shared a drink of bottled tap water. Heading downstream, the tide line could be seen on the muddy walls, becoming deeper as we approached the glutinous mud of the tidal sump. Much of the preceding passage had been flooded to a depth of 3-4 metres metres during the high tide. The mud proved quite tiring, and most of the party were happy to reach the beddings. Less happy when reminded that 150 metres of flat-out crawling in mud was in store before the entrance. Squelching and splattering, squeezing, climbing, slipping, and occasional face-kicking, until the heat-wave of the surface finally hit us. Otter Hole, there and back again, 10 hours.

Long Straw Gallery

I paid a quick visit to the tidal banks around the resurgence, and the choked lower entrance to the cave, but only found deer hoof prints instead of otters. The final trudge up to the car park seemed much longer on the return, with a detour to the "bath" (an elevated pipe dribbling stream water which can be used for washing faces in preparation for the pub). Refreshments and garlic bread in the sun at St. Arvans, and the day was over. 20 years I waited for that, and it was everything I had hoped for, and more. Massive thanks to our warden Pete for guiding us around this superb cave, to the meets secretary Claire for arranging it all, and to Helen, Dave and Nigel for the company!

Trip report: Tarquin Wilton-Jones, photos by Helen Stewart