China's hidden caves.
Time was the triumphant enemy when the China Caves Project team tackled the linked Great Crack and Great Doline caves in Sichuan, but this year we are determined to even the score.
The prospect of making the connection is as tantalising as ever, even though our survey data shows a 50 metre difference in elevation between the two underground sections, with their smooth walls and raging torrents.
When the connection is made, and we are confident that it will be, the traverse along the base of the Great Crack and through the entire cave system from sink to resurgence will surely prove to be a great adventure.
The British first tried their hands at caving in China 16 years ago and the practice has been accelerated by the gradual movement of the bamboo curtain in the 1980s. Prior to this we could only study maps and geology from afar and dream of what lay beyond our grasp.
China covers a vast geographical area and consequently boasts unrivalled ranges of both altitude and latitude. This coupled with a greater abundance of cave-bearing limestone rock than the rest of the world makes the country something of a Mecca for cave explorers.
A small group of British cavers visited China in 1985. Working alongside members of the geography department of Guizhou Normal University and the Guilin Karst Institute they explored and mapped caves in both Guizhou and Guilin provinces. This cooperation between Chinese geologists and British cavers has formed the basis of the China Caves Project. To date the team has fielded 12 major expeditions to the Hidden Kingdom and has never failed to uncover ever more spectacular cave systems.
The past three expeditions have concentrated on an area of limestone high above the Yangtze gorges in the Sichuan province of central southern China. Based in the small rural town of Xing Long, the team has been concentrating its efforts on the exploration of a system of caves associated with two of the geological wonders of the world.
The Great Crack runs for a distance of over six kilometres, an incredible gorge varying in width from only two to five metres at its top, yet more than 220 metres deep. Access to the base of the Crack and the traverse of it has required an exciting combination of abseiling, climbing, swimming and caving skills.
As the very first humans to enter this strange and remote place, we found a seemingly lifeless world lit only by a thin strip of light from far above. Bare walls scoured smooth by the force of water served to remind us of the powers that shape these unique karst landscapes. They also made us acutely aware of the risks of being hit by a flash flood -- a risk all too graphically demonstrated to us only a few days prior to our first exploration of the Great Crack.
In 1996 a team of four cavers entered a cave system located in the side of a dry riverbed upstream from the Crack. The team split into two, one pair surveying the upper reaches of the cave while the other team pushed on down into unknown territory. The first group successfully completed their task and surfaced after six hours underground to find a major thunderstorm in progress. With no way to warn their colleagues now far below they could only sit and wait with a watchful eye on the still dry river bed. After a nail-biting 14 hours the second team surfaced blissfully unaware of the storm having explored the cave 135 metres below the dry riverbed.
The storm continued throughout the night and the next morning the "dry" riverbed was found to be in full flight with the cave entrance and obviously the entire cave system several metres below the water level.
It was only when we abseiled into the far end of the Crack where it is at its deepest that we realised that the entire feature continues underground, forming its own spectacular cave. Even more exciting was the fact that this cave was heading directly for another, several kilometres away, and the second geological wonder in this area has to offer -- the Great Doline.
Dolines are naturally enclosed depressions not formed by any surface features and the Great Doline near Xing Long is considered to be the world's largest. Here in the UK we are used to dolines that are a few metres across and deep. With this in mind a first sight of the Xing Long doline is truly awe inspiring. More than 500 metres across and 680 metres deep it is a huge natural hole.
The cave system that has formed it is one of the world's largest yet is dwarfed by its surroundings. A winding path clings to the sheer walls and leads after an hours steep climb into a world of eternal shadows. Many years ago the Chinese realised the potential of the huge volumes of water running through the cave and set about harnessing its power.
By building a small dam across the cave's entrance they created a lake from which the water is diverted via a tunnel. Dug 1.5 kilometres through the mountain to the valley beyond this tunnel feeds a hydroelectric power station that supplies power to this remote region.
When the first China Caves Project team visited the site in 1995 they made little progress upstream against the full force of the water and turned to exploring the cave leading downstream. With the hydroelectric scheme taking virtually all the water this proved an easier task leading eventually, after 3.5 kilometres underground, to the far side of the mountain and a spectacular 40 metre-high waterfall into the gorge below.
Having completed this part of the exploration we turned our attention to the spectacular 150-metre-high upstream cave and the tantalising possibility of a link with the similarly large cave at the end of the Great Crack. Progress was slow moving upstream against the force of the river, in passages up to 60 metres wide. Once beyond the entrance the roof is never seen again, giving a strange feeling of being in a huge canyon at night. The team were eventually halted at the base of a series of small waterfalls.
Fired by the prospect that the downstream Crack cave and the upstream Doline cave were almost certainly one and the same we returned to the area late last year to attempt the connection.
Our plan was for one team to work downstream from the Great Crack cave and another to push on upstream from the Great Doline hoping to meet somewhere in the middle. As ever, the theory was simple but the practical application proved somewhat harder. The Crack team dropped down the 22-metre shaft to the cave and started downstream.
Swimming across two long lakes they soon met a section of fierce whitewater rapids filling the passage width and threatening to carry them away on a suicidal journey through the mountain. We already knew from our survey data that there was a 50-metre difference in elevation between the two caves so there was a very real risk of encountering a major waterfall in the middle of the system.
It soon became clear that the entire downstream cave would have to be rigged with fixed safety lines, a task that required a huge amount of equipment and a great deal of time. At the other end of the system we forced our way upstream to the previous limit of exploration where we managed to climb out of the river onto a ledge system. Climbing and traversing along the walls 50 metres above the river we eventually managed to bypass the waterfalls and drop back down. Crossing the river repeatedly we soon reached a large, tranquil lake. We could hear the distant rumble of falling water, however, and crossing the lake led to a narrow section of passage carrying the full force of the river in a foaming white mass. Normal progress was impossible so we resorted to drilling expansion bolts into the smooth walls and climbing along the walls like spiders. After a period of slow but steady progress, the entire river suddenly dropped from above us, down a 12-metre-high waterfall.
With communication impossible against the noise we climbed on and reached a small ledge from where we could see the water approaching down yet another smooth walled lake, offering no sanctuary or warning before the big drop. Our fears for the downstream team had been fully justified and we consoled ourselves with making plans for our next assault. This time we will make it
Fellows of the Royal Geographical Society can hear Gavin Newman and his fellow cavers describe their adventures in China in London, on Monday 18 May. Contact Alison Glazebrook on 0171 591 300 for more details.