Exploring the unknown depths of the remote and spectacular Turkish cave system of Altinbesik was the aim of the Dragon Cave Diving Expedition, although nothing ever turns out quite as planned.
Martyn Farr describes the adventure
The mules lurch from side to side, slipping and stumbling on the cobbled street. Strapped to their backs are 18 cylinders and a vast array of other technical hardware. It has taken us more than two years to prepare for this "high-tech" expedition and here we are employing one of the oldest forms of transport in the world - a muletrain - as the only way to get our kit to the site of our intended exploration.
In a team of six, we have come to the Taurus Mountains of south central Turkey to tackle some of the most challenging cave sites on the planet. Our quest is original exploration at the bottom of the 1000m-deep Manavgat Gorge. Set beneath deep-blue, cloudless skies, the river Manavgat has carved its way through incredibly tortured geology to form one of the most rugged, remote and inaccessible limestone valleys in the world.
At the foot of the gorge lies the renowned and perhaps most beautiful cave system in the country, Altin- besik Cave. This is a huge cave by any standard.
During the winter and spring, the water level in this cave rises by more than 80m, completely flooding most of the known system before thundering out into the Manavgat Gorge.
In early summer, the outflow suddenly ceases and a sombre silence settles on the underground galleries. It has been suggested that the water that disappears into the ground on the southerly shores of Lake Beysehir reappears in the gorge after a subterranean journey well in excess of 30 miles. This is certainly one of the longest underground drainage conduits in the world, and to date remains wholly unexplored. It would appear that Altinbesik Cave is associated with this network in some way.
Into the underworld
Altinbesik could almost be described as a fantasy world. As we discovered on a reconnaissance trip in 1997, the underground terrain and frequent obstacles could have come right out of an Indiana Jones film.
Set beneath towering cliffs, the entrance is vast - perhaps 40m wide by 40m high. It is occupied by a deep and tranquil lake, a pool of turquoise water running away into the blackness.
Some 200m from the entrance, the waterway terminates abruptly in a cul-de-sac. On three sides the walls rise sheer for as high as the eye can see, and draped into the vastness of this "terminal" cavern are flows of calcite, containing crystals that sparkle like gems in the light of our lamps. This place has the atmosphere of some vast flooded cathedral.
The only way forward is by climbing. This ascent is the key to accessing the major part of the system, and involves a 44m vertical climb directly above the lake.
From this lofty balcony, we look out on the twilight world of the lake far below. Ant-like, the boats carrying the rest of our team glide across the mirror-like surface and disappear beneath the overhanging walls.
Unclipping from the rope by which we scaled the climb, we turn to be confronted by the next lake, another deep, wide and black waterway that disappears into the vastness below.
The cave continues in this vein: lake after lake interspersed with slippery, razor-sharp rocks and short climbs. After the fourth lake, the profile of the cave changes. We emerge into an enormous hall where the floor falls away steeply. Black, brittle rock gives way to wet mud, then sand, and ultimately to shingle.
About a mile from the cave entrance and 80m below the level of the last lake, we arrive at the sump. This is the first objective of the Dragon Cave Diving Expedition and is the most serious obstacle in the cave so far.
Geared up
The dive logistics are immense. To field a team of three through the first sump and on to the "end" of the cave requires very careful preparation. From the outset, we planned the undertaking so that, if necessary, we could camp beyond the first sump.
To this end, the transport of equipment both through the cave and through the flooded section became crucial. Apart from conventional steel cylinders, we used ultra-lightweight carbon-fibre "composite" cylinders. But, despite being significantly less than half the weight of steel bottles of similar capacity, a considerable quantity of lead must be carried to counter their buoyancy.
However, by this approach the overall weight of equipment can be spread more evenly between the divers and some lead can be abandoned at the furthermost dive site and not have to be brought out of the cave at the end of the trip.
SCI-EFIC at Nottingham supplied the expedition with a variety of cylinders up to 300 bar, fitted with special cylinder valves manufactured to a high specification by Midland Diving Equipment.
For the underwater "ferrying" of equipment, we were using Draeger Dolphin semi-closed-circuit rebreather units. These give clear advantages in terms of gas duration, and were ideally suited to the project due to their ease of maintenance.
One of the more interesting difficulties we experienced concerned nitrox, which is generally unavailable in Turkish recreational diving. Thanks to advice from the Ekol Diving Services, we were ultimately able to blend our own supply. Things are just that little bit different in Turkey - oxygen, for example, comes in lovely blue cylinders, and fittings are far from standard.
Reaching the end
We have allowed three weeks for the project, which, if all goes to plan, will be ample time to reach the terminal lake and mount one or more missions into the unknown. Within 10 days, we have rigged the cave with a full complement of equipment and passed the first sump.
The flooded section is vast - a huge tunnel perhaps 30m or more wide and 5-7m tall. From air to air, the dive is more than 120m in length, with an average depth of 17m. The floor is littered with the largest cobbles I've ever seen, while the roof is plastered with fine sediment that quickly reduces visibility to less than a metre.
This obstacle had first been passed by a Czech expedition in the early '90s which had subsequently returned to progress the exploration to a point approximately two miles from the cave entrance.
Given the sheer immensity of the place, a compass bearing proves to be the most effective navigational aid, as the original guideline has long since been swept away in the dramatic winter floods. To lose the line in a site such as this doesn't bear thinking about!
The terrain beyond the sump gives little respite from difficulty as the cave rises steeply from the sump pool through an absolute chaos of muddy boulders. This area contains the largest cavern in the system, which quickly takes us once more to a height of 70-80m above the level of the sump pool.
Only at the very highest point can any footprints be faintly discerned in the sediments. Evidently, this whole section of cave is completely flooded in the winter - a sobering thought. From the high point, an equally steep slope takes us down to what proves to be another sump.
A shredded length of old line is a clear indication that this is in fact the route forward, while a climb directly above shows that in all probability this barrier is very short. From the vantage point 15m above the sump, we can see another large cavern just ahead, but on this occasion without the necessary equipment to descend the drop, or to dive through the flooded section, we are forced to withdraw.
At this point, the fickle hand of fate comes into play. It transpires that part of our political "permission" is not in order. Despite lengthy - and expensive - undertakings before the expedition, we now find ourselves compelled to secure the necessary paperwork, or risk the same fate that had befallen our predecessors. The Czechs had returned to continue the exploration of the cave in 1997, only to be refused access. In fact, they were turned away (out of the country) without being able to venture underground at all.
We spend several days trying to resolve the problem before we can resume activity. Given the delay, all our plans are thrown into the melting pot. The limited time we now have renders it impractical to continue with the original objective.
New discoveries
But every cloud has a silver lining - when two of the team discover a far more exciting project at Martal Cave, the decision to withdraw from Altinbesik becomes suddenly much easier. Turkey is experiencing a major drought, and in a flooded, undived cave just a mile away the water level has dropped to such an extent that an airspace has been created. A gap of around 50cm has now appeared over a deep lake, and through this opening a gale-force wind is now blowing!
Our expedition is back on track. In the days to follow, we explore Martal Cave and discover more than a mile of immense cave passages, including one of the largest underground caverns in the world - a void some 100m in diameter that generates distinct feelings of agoraphobia. Huge boulder blockages eventually obstruct the way, but there is, as is often the case, a distinct possibility of being able to bypass such obstructions by diving.
The Dragon Cave Diving Expedition, sponsored by the Sports Council for Wales and others, was a hugely rewarding venture. It explored a major new and previously unknown cave system, and gained a wealth of information about a number of other sites. And, as for Altinbesik Cave, which will probably be proven to extend for an incredible distance under the Taurus Mountains, diving is assuredly the key to its exploration.
Certainly, the Manavgat Gorge is one of the most attractive exploratory propositions of our time, and today is an even greater challenge to those who will follow in the future.
