Daren Cilau


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Sunday 14th July 09:30am, two divers begin to amass diving equipment at a quiet Welsh resurgence ready for the days diving/ caving activities. The water flowing down the valley appeared clear and little flow was coming out of the resurgence due to the lack of recent rains.

The plan for the day was to reach the current terminal boulder choke at the divers end of Daren Cilau, thought to lie very close to the downstream end of Agen Allwedd. This had received some attention in the past, circa 10-15 years ago but it doesn't appear to have been looked at since.

The previous explorers certainly gave it a good go by all accounts and as is the way it seems the previous generations often pushed harder than those currently undertaking such trips so our objective was primarily to reach the boulder choke and see it for ourselves.

The trips begins with a vertical descent to a mobile slope of stones which is turn leads to a narrow gap that often needs some clearing for a laden diver to get through, once through this obstacle the swim to the dry cave beyond can begin. Depending on the visibility the diver might have a single wall or a single bit floor for company but seldom more than one owing to the size of the passage and the usually murky waters found here.

A swim of around 30 minutes is usually enough to reach the end of what must be the longest known cave dive South of the Northern Regions, many sumps in the North eclipse this but in the South we are not blessed with such long known underwater sections. Surfacing at the end the square form of the passage leads off into the distance and the sound of running water can be heard.

Depositing some of our equipment here we move up to the junction to the 'Kings Road' which in turn leads to the well known camp the 'Hard Rock cafe'. We begin the unpleasant task of removing out nice warm drysuits and putting on our nice cold wet wetsuits in which we will remain for the rest of the trip until returning to this point having carried them a in bag each through the sump.

Once this exchange had taken place we began up the stream way which is very slippery in places to St Davids Lake, a peat stained out of depth swim. This in turn leads to St Davids sump a mere 40 m in length compared to the 600 m swim of the preceding dive. This only takes a few minutes before we reverse the transition to become cavers again still laden with diving gear.

Walking in large passage sets the scene for the most part of the next 800 m of cave, occasional climbs in fossil sections break up the streamway and pools which are nice to cool off in occasionally. The roof begins to lower after leaving the water behind and you are forced into a crawl for the final 50 m or so before the slope down to the next sump, aptly named the GLOOM ROOM ! This can only be described as a muddy funnel in a giant cup of tea, much easier going down than coming back up.

Here we pick up another cylinder each which had be pre-staged on a previous trip and begin to unpack our gear and get ready for the next flooded section. The Gloom Room's muddy static pool is in fact a window into the active flow beneath. Once you have groped your way to around 13 m depth you find a slight improvement in visibility and a horizontal tunnel leading off upstream. This is followed for around 250 m before surfacing in a very similar shaped but much smaller passage than the end of the main sump to dive in Daren Cilau, the characteristic square shaped passage leading off upstream again.

Further adjustments with diving equipment here were made, primarily the ditching of rebreathers as the next two sumps are short, our reason for using rebreathers to this point was the unknown state of the dive line and murky conditions in which one would have to attempt repair or replacement of any missing line. We didn't want to get so far as to be turned around by not having enough time underwater to remedy this and rebreathers afford such luxury compared with traditional open circuit equipment.

The passage from here on had been named 'San Augustin Way' which is even grander than the passages before it, often over 5 m tall a large sweeping stream way cut into grey scalloped limestone. This was enjoyed for 20 minutes or so before the nature changed completely, it became very narrow and often with canals to shuffle through less than a shoulders width apart forcing us to turn sideways, the rock had become much darker at this point and of course of progress slowed dramatically.

The passage didn't relent, it took a number of very abrupt direction changes not far off 180? with each turn again in the much darker rock before finally reaching the next sump pool. A quick examination found the line to be broken so our line reel carried all this way for the purpose was attached and steadily laid out by myself.

I started off following the right hand side before reaching what appeared to be a  blank wall which I followed to the surface thinking I would be in one of the air bells I was expecting to come across, I could see lights back at dive base so slightly confused I reeled back in to my previous belay before I cast off in another direction hoping to find open passage. This was eventually found way over to the left then a very similar repeat of the process was made this time surfacing in an actual blind airbell rather than back where I had started.

I was now beginning to realise the more complex nature of this area of the cave than I had originally given it credit for but after a few more blind alcoves were searched I found some remaining line intact and tied into it before following it the remaining 40 m or so to surface pleased I had eventually managed to find the way.

A chilly 5 minutes were spent waiting here in deep water for the arrival of the dim glow of lights to appear signalling the arrival of Chris who had given me a decent head start. We swam up the passage against the flow and had to take our fins off for the last section before the line appeared for the final sump.

I had used more gas than I had planned relining the previous sump so thrust the line reel over to Chris (he had more than me having just swum through) in case any work was needed here, fortunately the line gods had been mostly kind and this sump still had its continuous line through it still well placed to the guide the diver through the muddy waters.

Gladly we removed all of our kit for the first time on the trip, and walked the short final section up to the boulder choke finally having reached what we had come to look at. The obvious holes on the left were first investigated noting the very loose looking nature of the place, a few smaller rocks disturbed raised my adrenalin levels slightly suddenly becoming aware of we where and the seriousness of any incident however minor that might take place here with falling rocks.

A few other holes were cautiously looked in, some areas were heavily calcited and were quite Mendip-esque in appearance. No major wall of obvious feature could be found that might guide the keen people who might one day take up a long term dig here, it is a very long way to bring scaffolding or similar to safeguard progress into the choke.

After a short time nosey-ing around we agreed to head out and pick the brains of those who had tried in the past as to what their thoughts were. Time to this point had been around 5 hours, so we slowly reversed our route gathering more and more equipment before making the rather more pleasant transition from wetsuit back into drysuits for the final swim to the outside world surfacing just after 9 hours from when we had left the sunny Sunday morning behind.

After some contemplation i'm of the train of thought that a more accurate survey of both caves would be of benefit so that the distance between the two ends might be more accurately known, this may further increase interest or further have the opposite effect of putting people off depending on the outcome. I would certainly go back and visit again and there are a few side passages along the way we didn't stop to look at being lazy and having to de kit each time was my excuse not to do so.

A thoroughly enjoyable Sunday out......................