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 inicio > artículos de buceo > tecnicas de buceo

Introduction and History of Moraig

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The name of the subterranean river Moraig has its origin in the age of the Moors. The Arabs who came from North Africa occupied the south-eastern part of the Iberian Peninsula until 1492. The expressions "El Morach" in contemporary Spanish and "El Moraig" in Catalan derived from "Fuente del Moro"(source of the Moor). Catalan is still spoken by the older people who live in the area of the river Moraig, located in the region of Cabo de la Nao (the eastern promontory on the Mediterranean coast of Southern Spain).

Presumably the entrance to the cave was known by the Phoenicians as early as 1000 years B.C.. It was them who founded the towns Denia, situated 16 kilometers northwards and Calpe 12 kilometers southwards in a coastal area, which is in general very poor in drinking water. According to old legends they drew their water supplies with the aid of earthenware jugs from the shaft of Moraig's mouth. STRABO (a Greek geographer who lived from 63 B.C. to 20 A.C.) reported that the Phoenician sailors applied - compared to the knowledge of today's engineers - sophisticated techniques in order to draw drinking water from the underwater sources. We may presume that at that time the salinity of the water at the river mouth was lower than today, because of fluctuations of the sea level during the last 3000 years. Nowadays the river's proportion of sea-water is too high to be directly used as drinking water.

In the course of history the place where Moraig flows into the sea was forgotten, not least because of its nearly inaccessible location on the foot of a steep coast. However, numerous legends exist on the underground course of the river and its hidden shaft at the mouth. In the villages you often hear the explanation Moraig rises from a lake in the cave somewhere under the mountains of Costa Blanca, or from an underground waterfall which never dries up. Farmers from Benitachell say it runs through a flooded Phoenician harbour ...

As late as in 1950, the population started searching systematically for the course of the river. In the same year the agricultural structure of many fields was fundamentally changed (this affected an area near the Moraig river of approximately 4000 hectares/15 square miles): Instead of growing wine, olive and almond trees the farmers started planting orange and lemon trees which need much more water. However, the few existing fountains and wells were not sufficient to cover the increased irrigation. Fishermen frequently told about a current coming out of the steep coast and drifting their boats out on the sea. Gradually the farmers became aware of the huge amounts of freshwater flowing beneath the land into the sea and which are for ever lost for the population. In 1956, the villages Benitachell, Teulada, Javea, and Gata de Gorgos joined together in order to finance a test drill hoping to meet the subterranean river. Savador Conzales de Haro, a deviner, was asked to find an appropriate place for the drilling. He chose a spot on the western side of Montaña Llorensa at an altitude of 200 meters, from the technical point of view a very disadvantageous place. Nevertheless they drilled a 75 meters deep shaft and discovered a cavity filled with air. In order to prove there is a connection between the river Moraig and the shaft, a red liquid was poured in. According to the daily newspaper 'Información' the whole village of Benitachell came to the steep coast to watch the red colour that flowed out of the river's mouth into the sea. This is said to have been the most important day in the history of the village. After that, the farmers and their helpers, 700 people altogether, digged, with the aid of picks and shovels, a larger shaft which gradually became 110 meters deep. This means that there were still 90 meters missing to the ground-water level. The works had to be stopped for lack of government support.

In 1967, speleologists from Alicante took interest in this unsuccessful adventure. They explored the entrance to the cave, and drew up its topography. This enabled them to confirm to the mayor of Benitachell the existence of huge amounts of water (1.500 to 10.000 liters per second, depending on the season) flowing out of Moraig. At the same time, the speleologists Eloy Parra and Jaime Carbonell realized that the high salinity makes the drawing of drinking water directly from the river's mouth impossible. They hypothesised there would be pure drinking water deeper in the cave-system.

In 1974, Eloy Parra for the first time dared to dive into the depths of the cave, and this with very simple equipment. According to his memoirs, after the first few meters under water, he only saw a tunnel which dropped vertically. As late as 1978, he managed to venture as far as 200 meters. He brought back survey-drawings and water samples. Since the analyses showed a too high proportion of salt, even at a distance of 200 meters to the exit of the cave, he stopped his investigations.

In 1982, the speleologists Juan José Palmero and Vicente Alegre attempted to continue Parra's works. On July 11th, 1982, they crossed the 200 meters frontier reached by Parra, and went as far as 260 meters. With more sophisticated equipment, they started another attempt on July 18th, which they did not survive. After having waited an agreed time, one of the security divers, who was waiting at the exit, followed the guide line into the interior of the cave. He found Palmero at 160 meters from the exit entangled in the rope without his bearings and his compressed air bottles being empty. Alegre's body was found and recovered at a distance of 470 meters on July 20th, thanks to the cooperation of 9 rescue teams. The exact cause of their death remained unknown.

In October of the same year, the speleologists of the 'Grupo Standard de Madrid' started an expedition in order to enter even further into the cave-system and to find freshwater. All attempts had to be stopped at a distance of 550 meters from the exit, for defiles and the increasing depth of the water making any advancing impossible.

In 1985 and 1986, because of heavy rains, the river's current was too strong to enter the cave.

In 1987, the speleologists Mateo Gonzales and José Cortes of the 'Grupo Espeleologico Alicante' suggested to several governmental authorities a research project for Moraig: A topography should be drawn up of the subterranean course of the river and its geological origin should be analysed. However, the project could not be realized for lack of governmental aid.
The Course of the Moraig Project:
At the end of 1987, I ventured for the first time into Moraig following the former guide-line of Eloy Parra. I was absolutely fascinated by the huge dimensions of this cave, but also aware of the great dangers. For serious investigations, I soon realized the necessity of appropriate cave diving equipment and experience. A long time of preparations was lying ahead ...On the other hand, the importance of Moraig's exploration was obvious: The course of the subterranean river is situated near to the most arid region of the Mediterranean Europe. Owing to annual precipitations of less than 200 millimeters in places, the farmers have not enough water for their terrains and even the well's drinking-water supply is not sufficient for the population. The river Moraig could prove to be the solution to this great problem that has existed for generations.

In 1988, I was preparing adequate cave diving equipment that had to be adjusted to the difficult conditions inside the cave. With the help of the Norwegian design engineer Louis Nielson and the German technician Gunther Kopp, an underwater vehicle was constructed taking up months of labour in the workshop. This vessel enabled us to reach greater depths in Moraig, and transport extensive parts of the equipment such as illumination-systems, supplementary air tanks and cameras for documentation purposes. All material was meticulously tested in swamps and water filled caverns in Germany. Deep tests were made in the fjords of Norway.

Jochen Hasenmayer, a worldwide known cave diving pioneer, gave final advice to our project. For safety reasons, he emphatically recommended to go on cave dives alone, even if this is not usual for open-water diving. In extrem dangerous situations, the diver can only take responsibility for his own life. Trying to save his companion in the risky circumstances of the cave will endanger himself inevitably.

In the beginning of 1989 we received all necessary permits from the various Spanish ministries affected by our forthcoming project. After final tests of the vessel in the open sea, the first dives were made in collaboration with local speleologists. The transportation of expedition material from our base camp to the harbour and from there on a dinghy along the coast to the cave-entrance cost almost 6 hours of time respectively. Then, inside the cave, we prepared a deposit of air tanks at a water depth of -9 meters. They contained 10.000 liters of compressed air as security for my return in case of decompression. During the dive I carried 4 back-mounted tanks with an air supply of 6800 liters calculated for an average diving time of up to 4 hours.

The expedition aim consisted in the drawing up of a detailed topographical map. This one should enable a precise drilling to a localized freshwater occurrence inside the cave system. In the longest dives, I could reach an extended labyrinth lying beyond the 650 meter point. After months of intensive cooperation of meanwhile 15 team members, we have not yet achieved any positive result. All of the water samples, taken up from different distances, still showed a too high content of salty sea-water. At the end of march 1989 we had to break off the expedition, because of unexpected storms. Furthermore the dinghy was destroyed and an essential part of our equipment was stolen.

Before recommencing the project in July 1989, we took occasion to repair and improve our equipment in Germany. In Spain again, I tried to continue the exploration in Moraig. But I didn't manage to find the main passageway of the river, because of the complexity of the labyrinth with its numerous crater-like holes. Although the recent water samples again didn't contain any freshwater, we could observe that the salinity in all of them is not varying at all. (The water's conductivity amounts to approximately 17.900 µS/centimeter at all examined places in Moraig.) This means that the sea is definitively not intruding by the entrance, but somewhere beyond the up to now explored sector of the cave system. Quite by chance, I discovered an example to this assumption at the end of an unusual sediment funnel: A source of saltwater. At this point the sea, due to the higher density of its salt containing water, flows into the river. In order to explain the formation of the river's percentage of 10 g/liter, the existence of several other such sources has to be suspected. Thus, the occurrence of drinking water in the Moraig-system can only be found at greater distances... In September 1989, the project was interrupted because of the annual autumn storms.

Continuing in October, I could detect the river's main course diving at 710 meters into the hugest crater-like hole of the labyrinth. This vertical shaft drops to a depth of -40 meters leading to a passageway that descends gradually to further depths of -50 meters and finally to -62 meters. There, the increased water pressure means the coming on of nitrogen narcosis which affects the concentration on the dive and the complicated steering of the underwater vehicle. To elevate the security, a second stage of air tanks was prepared at 700 meters. Furthermore two additional tanks were connected to the vessel extending the autonomy of the diver considerably. Till the end of the year, 1085 meters were reached, but the analyses of the water samples remained negative.

As a small aside-result, a crustacean was discovered in one of the passageways, propably belonging to an undescribed species. We are still working on its zoological classification.

A change of mood in the expedition-crew came unfortunately with the unexpected death of our team member Mateo Gonzales in a cave diving accident. A long period rethinking the diving mission and research activities followed this mishap ...

In January 1990, our project went through another setback: In the base camp the stored equipment was flooded and damaged by infiltrating rainfalls.

Early in May, provided with new material, we set the wheels of our investigation turning once more. Equiped with an extended air supply of 16.000 liters and a dry-suit with better isolation qualities, I was able to shift the borderline of exploration deeper into the cave. The prolonged diving times of 7 to 8 hours required on account of a higher nitrogen absorption, additional attention to the decompression. At the entrance, we completed the air tank deposit up to 18.400 liters for safety reasons. After nearly 100 dives, 1160 meters were reached and the total length of the explored passages in Moraig covered 2075 meters. Nevertheless, all of the water samples still resulted in a too high proportion of saltwater. It was soon obvious to me, that deeper dives were not reasonable anymore. We found ourselves at the limit of our technical possibilities. The Moraig project seemed to come to an early end.

But there was still one phenomenon I couldn't understand: How was it possible for the Phoenicians to draw drinking water out of Moraig's mouth at that time? In the library of my home-university, I met with a solution to this mystery looking at a diagram of the U.S. geologist Rhodes W. Fairbridge. According to him, in 1000 B.C., just in the time when the Phoenicians landed in Southern Spain, the world sea levels were about 3 meters lower than today. Perhaps this may explain the former drinkability of Moraig's water. Perhaps this also could lead to a solution of our main problem: We have to recreate artifically the hydrostatic situation that existed once in Phoenician times by means of a construction of a wall in front of Moraig's mouth. The river-water could then rise behind this wall to a certain height where it forms a counterpoise against the sea-water which is heavier due to its salt content. Thus, the wall will effect a higher water pressure inside the cave system and consequently stop the intrusion of the sea through the saltwater sources.

So far a theoretical solution. But which altitude the wall must have? For its calculation we have to count with sources of saltwater appearing at depths of down to -100 meters beneath today's sea level. They date from the most recent Ice Ages functioning as off-leading channels for the river down to ancient sea levels that were situated about 100 meters lower than nowadays. (During the Ice Ages, voluminous amounts of the water in the world's oceans were frozen into solid glacial ice at the Poles.)

The necessary altitude of the planed wall is directly dependent on the deepest possible intrusion point of the sea into the Moraig system, that means at approximately -100 meters. There, the pressure of the river-water must be equalized to that of the denser sea-water by raising the river's surface up to the height of 2,75 meters above the sea. This is calculable as follows: The pressure represents the product of the water's density and altitude. A 102,75 meters high column of freshwater (possessing a density of 1,0005 g/cubic centimeter) develops the same pressure as a 100 meters high column of saltwater (density of 1,028 g/cubic centimeter). Consequently the construction of an at least 2,75 meters high wall at Moraig's mouth will be necessary to dry up our deepest presumed saltwater sources.

In the course of 1991 - 92 the governmental authorities of the district of Alicante gave all necessary permits for the planed construction at the coast. In order to conserve the original aspect of the coastal landscape, the dam is scheduled for the inside of the cave's entrance-hall. The building-plans have been already calculated by engineers of the university of Alicante and Valencia, the construction itself is proposed to be realized by local architects in the coming years.

Bernhard Pack, March 5th, 1992
Bitte beachtet das Copyright:
© Bernhard Pack, Weiterverwendung nicht gestattet!

 

*Contenido extraido de la Web http://www.weber-joerg.de/moraig.htm

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