7 minute read
SPAIN
from The Edge #1
Southern Spain is not the first place you’d think of being home to a stunning sinkhole, but Murcia’s Cartagena has been a regular haunt for cave diver Garry Dallas for the last five years, and he is entranced by the Cave of the Water
PHOTOGRAPHS BY GARRY DALLAS
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In a quiet little town in the suburbs of Cartagena in southern Spain, Cueva del Agua - meaning Cave of the Water - resurges literally on the edge of the main road through Isla Plana and is one of the most-popular and most-accessible sinkholes in Europe.
This quaint little spot in the driest, warmest and sunniest region of Murcia has been my destination for the last five years where I dive and teach cave courses. The structure of this cave is similar to cenotes normally found in Mexico, where sinkholes in the ground naturally filled with water, or have water flowing through it. Originally the word ‘cenote’ was used by the native Mayans in the Yucatan Peninsula, Mexico, which they pronounced ‘seh-noht’, meaning ‘sacred well’. When the Spanish settlers came to Mexico in 1519, they interpreted the word as ‘seh-note’. Over the years, the pronunciation has been better known as ‘cenote’ by people around the world. The Spanish terminology for this type of sinkhole has been used around the world and here in Spain for this cave.
Cueva del Agua was formed in a geological Karst terrain, but unlike most solution caves where the colder water flow comes from the high mountains in these areas, extraordinarily, this cave is hypogenically and geothermally heated to 29.5 degrees C throughout the year, except for the first 6m of fresh drainage water from rainfall. As the water flows from the mountains, possible ancient seismic faults in the deep underground terrain cause this water to be heated and driven by hydrostatic pressure upward to the surface, where it meets the fresh/sweet-water halocline, before it goes out to sea.
The water table has never been low enough here for speleological formations like stalactites and stalagmites to evolve, however due to the abundance and composite nature of the minerals and ores within the cave, she reveals some pretty stunning colours.
Dive teams from all over the world arrive here throughout the year, usually in drysuits based on the dive times they intend to make. Parking isn’t ample, so it does mean getting there early doors and be cautious leaving anything around. Once you’ve rigged up your tanks, sidemount here being marginally preferred, the ‘steps’ down to the water consist of small secure boulders modified by local teams to make life a bit easier, so take care, or you could use the pulley system left there by the Spanish exploration team. Fernando Gázquez, José María Calaforra, Tomás Rodríguez-Estrella, Andrés Ros, José L. Llamusí and Juan Sánchez are members of that original exploration team, some of whom I’ve met over the years, which was an honour. It’s hard not to notice on the left-hand wall of the entrance there are two plaques, always decorated with flowers, in honour of three experienced recreational divers who didn’t make it back home to their families.
Kitting up in this crescent-moon-shaped pool is a doddle - ample surface light means buddy checks and final plans can all be made without any difficulties.
Mind you, just watch out for the occasional happy jumper from the overhanging rocks!
As you descend to make your primary tie-off out of sight from the tourists, visibility can be breath-takingly gin clear with a stunning light show piercing its way through the rock entrance and refracting through the water. Secondary tie-offs are plentiful in a few metres of water, large boulders provide reference with smaller rocks jutting out from them and the walls to attach your line to as you descend towards the dripline. At 6m you hit the halocline! What was charmingly warm suddenly feels like an emersion into a very warm bath. The temperature difference from 20-24 degrees C at the surface rises to 30 degrees C instantly as you descend past the 6m mark and continues for the rest of your dive throughout the entire cave system.
You realise the size of this huge cavern as you make your way towards the main line using the bearings you took from the map. There are a few short permanent lines around this cavern that are definitely worth investigating. After 80-100 metres swim at 10-12m depth, belaying along the way and depending on the route you take, brings you to the main line concealed slightly behind a large rock formation hanging from the ceiling. The big white notice attached to the main line is clear for those not trained in cave diving.
After connecting to the main line, a team confirmation of gases and attendance markers, you head off along the clear large passages or detour along some interesting smaller ones. All the main lines at junctions are clearly marked from each direction which is the way home. Slightly different marking system from other country’s methods, but nonetheless, clearly marked to indicate the direction of the main line home.
Around 200 metres from the entrance along the main line, as you look to your right and below, is a single tank attached to a BCD and regulators. This is a stark reminder of the misadventure of a diver who lost the line in zero visibility and didn’t have sufficient gas to return home. Training, practice and the realistic measure of one’s abilities and experience is something that can only be emphasised for this type of diving.
As you reach the next junction, the second ‘T’, you check gases and place a team marker on the exit line. Taking a left brings you onto a lovely circuit dive, illustrating large areas of brilliant white quartz mineral as well as other calcite deposits on the walls and ceiling. Turning right takes you further into the cave. Moving further into the cave, if you just stare at the diver’s fins in front of you, or focus entirely on the line, you’ll miss the pictures on the walls and ceilings that show other geology and minerals in the rock. They are quite spectacular and decorative and not really what you’d expect to see in some caves. There are plenty of markers identifying ‘jumps’ to
other passages along the way, but these are for the moreexperienced cave diver. Visibility can soon deteriorate when percolation from the diver’s exhaust bubbles hits the ceiling around you. For some unknown reason, the letters SAS have been inscribed in the silt floor in a wide open passage around 350 metres in, which can only be described as graffiti. This is entirely frowned upon in the cave-diving community and disrespectful. Elevations will change some 400 metres into the cave and there’s a chance to see more haloclines as you pass through fresh and ‘sweet water’ around 8m or so. Sweet water is the slightly salty version of fresh water, with the notability of being somewhat warmer too. Cave dimensions tend to change a little from here on becoming narrower and wider, before you hit a maze of multi-directional lines. Good solid navigation techniques are required here, as well as ample gas before continuing towards Juan Sanchez’s Pass at 860 metres.
It’s taken the Spanish exploration team several years and hard work to make the next part of the cave system ‘accessible’. The hole in the floor, where the hydrostatic pressure of the warmer water gives its name to this hypogenic cave system, is tricky to get through and this requires sidemount configuration, while reserves are left on the home side or planned and carefully transferred through. On the other side, it’s a different world. Temperatures are a little warmer still and the water has definitely got a more blue-ish tint to it. Rock faces are covered in stunning fern-like calcite deposits which are extremely delicate, especially to exhaust bubbles from the open circuit diver. Passages have a totally different shape to them: one I passed and noticed was the size of two double decker buses next to each other, while the main passage was becoming more fissure-like.
It was a wondrous and worthwhile experience to dive beyond the Juan Sanchez Hole with my buddy Victor and appreciate the work of the Spanish explorers before me to ascertain the phenomenon that resides in this cave.
Over 4km of passages have been have been surveyed, including deeper levels going down to 22m. The expedition and study continues to this day as the team members are getting excited to reveal more of the nature of this cave system. n
