Agua '86

by Gavin Newman and Julian Walker.

Originally appeared in Caves and Caving No. 36.


The summer of '86 saw 5 British caving expeditions visit the Picos de Europa in Northern Spain. Over the past decade this area has been host to the deepest British explorations in the world, with OUCC pushing Xitu to -1147m in 1981 and LUSS following just 2 years later with 56 to -1169m. The resurgence to 56, La Cueva del Agua, some 1500m below, also happens to be the 2nd longest cave in Spain.

Picture: Agua Mainstream

Agua was originally explored by LUSS in the late 70's until they had discovered 10km of fine passage. The way on eventually eluded them when both the main streamways sumped and no bypasses could be found, despite a strong draught. Other caves in the area told a similar story. Marniosa, a dye traced stream inlet to Agua, ended in a downstream sump whilst Chico, a flood overflow to Agua did the same.

So it was with this potential in mind that a smallish cave diving expedition was put together. In addition to diving the sumps we also intended to push any dry leads that came our way and so a team of 18 cavers and divers spent 3 weeks in Tresviso. Armed with a small compressor and a mountain of diving, climbing, underground camping and rigging gear, we set about rigging into Agua and Marniosa.


Marniosa was the first to yield. The cave was rigged on our first day, and Colin Boothroyd passed the sump on day two. A 35m sump lead to 650m of spectacular stream passage ending in 15m pitch. Colin returned after 4 hours beyond the sump to a cold and bored Steve Jones.

Steve was at the sharp end the following day, when he and Gavin Newman went back to descend the pitch whilst Colin and Ian Rollands surveyed. At the bottom of the pitch a deep pool was crossed, but tight rifts led to another sump. It appeared that an easier lead was in the roof, so an aid climb was undertaken opposite the 15m pitch.

This was completed after a number of trips by Colin, Ian, Steve, Fran Hampton, Rich Barker and Rob Parker. A further 600m of stream rift was found, terminating in yet another sump. Unfortunately, a lot of this section was tight and sharp and particularly unconducive to bottle carrying. A total of 1.5km of new passage was surveyed in Marniosa, and a through trip to Agua in years to come is definitely possible.

The first aim in La Cueva del Agua was to put Rob Parker into a major sump at the top of the Road to Certain Death (the Certain Death sump). This is the upstream point of Agua's second streamway, situated at the top of a 10m pitch. The diver has to kit up before climbing the pitch and finish fitting whilst treading water. Despite this it is a superb dive site, with large passage and superb visibility.

Rob had dived the sump in '85, laying out 120m of line and ending at a depth of just -5m. The sump was not to surface, however, as on his first dive this year it dipped immediately back down and Parker turned at a depth of -30m some 170m from base.

The next dive was a different affair, with Rob taking 250 cu.ft. of air and using a dry suit. This time the ceiling forced him down to 54m at a point 210m from base. This was the limit of Rob's decompression tables, and so he had to return. A 47 minute decompression schedule allowed the diver to surface.

One final dive was made. Using the same kit as on the previous dive, Rob made a 240m penetration to 64m. At his far point, he reached a vertical shaft up which he could see his bubbles ascending for at least 20m. It was not practicable for Rob to surface beyond the sump with the complicated decompression this would require so this point now marks the limit of exploration in Certain Death.

The Back End

At the back end of Agua a complicated maze of passages is entered. The main stream disappears into an upstream sump whilst the strong draught is lost. We had three leads to follow in this area and so set up a four man camp in Consort Hall.

The first of our leads was an open downstream passage leading back towards the entrance. It was hoped to follow this to any inlets such as Marniosa that might lie between the entrance and here. Nic Airey and Julian Walker pushed down the cascading stream, using a combination of techniques such as pendulums, tyroleans and swimming. A magnificent final chamber was found with a 20m gour pool ramp above the inevitable sump. In all 300m of passage was followed.

Our next aim was the upstream sump itself which appeared to be the only way on. Gear was carried into the camp by Rob, Ian and Howard Jones and the sump dived on a subsequent trip. Ian, supported by Colin was the first diver. He laid out all his 120m of line to a depth of -24m in passage varying from 10m to 20m diameter. Rob's dive followed, and a further 47m of line was added at -27m until the diver turned around because he was scared (he IS human after all). No more dives were made at this site. With all the other obvious leads at the back of Agua worked out we embarked upon our final hope of finding a route towards 56 and the caves of the the Andara region. The idea was to hunt the draught, checking out every lead from where it was last noticable. Nic, Julian, Roddy McLauchlan and Clive Gardener went in for the final camp before derigging began. It was in the Hall of the Green Dominoe that the draught was lost. At one end of the Hall, above the Bloody Lake, a hole could be seen in the roof. Rod made an exposed and unorthodox ascent up the wall of the chamber and into a steeply ascending passage. Some very necky soloing and 2 more aid climbs led Rod and Julian up into a complex of ramps with many leads which they could not follow up steep climbs. And there was a strong downwards draught! The ramps were followed for over 200m, ascending 192m above the starting point. The series earnt its name "Satan's Teeth" from a large stalagmite and stalagtite formation which the two climbers found at the top of a particularly frightening climb. The far point was both above and beyond any other point in Agua. This is now thought to be the major route out of the back end.

Picture: The Back End of Agua

Other Sites in Agua

Two sumps closer to the entrance of Agua were also dived. The first was the initial main stream sump just inside the entrance. This led through an airbell to a roaring stream passage after 45m, but unfortunately the passage had been entered from the other side.

Picture: Road to Wigan Pier Survey

Another main stream sump at the end of the Road to Wigan Pier is the first time the stream is seen again after disappearing into the downstream sump at the beck end, some 500-750m away. Colin and Jim Thomson set about diving this, later helped by Steve. They passed the sump after several attempts, surfacing into open stream passage 180m from base. This was followed to a 4m high waterfall and another upstream sump which remains undived.~ A bypass to sump 1 was found, and then a bypass to the bypass. In all some 400-500m of passage was explored.

Whilst climbing the waterfall Colin managed to split his finger open. Emergency first aid was administered underground by Steve, and some epic driving by Gavin got him to the "local" hospital in Oviedo some 100km away where 9 stitches were used to put it back together. This was the only accident of the expedition.

Chico is a flood overflow to Agua, some way along the Urdon Gorge. Shortly inside the entrance the first sump is met. This was dived some years previously by Colin who entered an airbell after 35m.

The second sump was attacked this year by Steve. On his first dive he dropped to 37m in a descending canyon. His second dive was accordingly planned to be a decompression dive, Steve setting himself a depth limit of 55m. At 55m the canyon was still descending so Steve prepared to return to his decompression tank and tables left at 9m. Whilst checking his gauges, however, he sank to 62m on account of being negatively bouyant. Realising his dilemma, he dropped the line reel and immediately began his ascent. He reached the 9m decompression stop only to find that his decompression tables were gone (they had fallen out of their housing!). Steve did not have a decompression metre with him, and was not familiar with the tables. However, he decided to used the rerriainder of his air before surfacing, and spent 45 minutes decompressing. Upon surfacing, he directly ran back up the 500m deep gorge to base camp to find that he had done the right times but in the wrong order! He spent the next two days worrying, but no signs of the bends were noticed and he's still alright now. A close one!


Cowshead Cavern

Tresviso is know for its cheese and they keep cheese in caves. This brought LUSS here 12 years ago, and it served us again this year. Gavin and Fran were returning from a prospecting trip when they passed the entrance to an old cheese cave which was resurging. They followed it to a choke, but the following day this was dug and 250m of passage followed to a sump. The skeleton of a cow(?) was also found, giving the place its name.

The sump was subsequently passed by Julian after a 100m dive and led to a further ?m of open stream passage and sump 2. This looked deep, but was only 4m long and easily passed by Rich Barker to 500m of open streamway and a large end chamber. The stream entered from a passage some 8m up the wall which Rob and lan scaled. Sump 3 was only a few meters beyond, but a few hundred meters of small oxbows were explored.

Picture: A diver in Cowshead Cavern

So the expedition returned with some 4km of surveyed and photographed discoveries and more leads than it started with. Another trip is planned for next year (The Agua Project eat your heart out, China) with Satan's Teeth and Cowshead as its primary objectives.

Agua '86 would like to thank the following for their support; Sports Council, Ghar Parau, Wookey Hole, SWCC, Steve Foster's Mum, Isca CC , Gavin, Varta batteries, Warmbac, Damart, Inglesport, Up and Under, Crickhowell Adv. Gear, Minerva Outdoor Centre, Agfa, Fuji, Dorset Diving Services, Tate and Lyle, Midland Bank, Brittany Ferries,