The famous Katavothres (swallow-holes) are an extremely rare geological phenomenon. The sea water flows inland to enter sink holes below sea level. In this area the people used the sea water to run mills.
It is rather difficult to understand, where the water goes, when it disappears below sea level. Obviously there are some caverns underground, which the water enters. But after some time they are full and the water should stop flowing. Sea level is a physical border, following the law of communicating tubes, water should flow from the side with the high water level to the side with the low level until both were at the same height. So after some time all caverns should be filled the same height as sea level. In the Mediterranean Sea, there is only very little tide, so this force is no good explanation.
Over the time numerous theories were made up, how this could work. They all contributed some details to the modern theory:
* Mousson guessed the source of the movement in volcanic activity in the ground, heating up the water. Warm water has bigger volume and a lower specific weight than cold water, so it would move up to the surface again. This would explain where the water goes. However, there are two problems with this theory: there are no thermal springs around, and how should this lower the water level at Argostoli?
* Fouqué used the law of communicating tubes for his theory. If the physical attribute of the water changes from one side to the other, the water level would be different in both tubes. The tube with the heavier liquid would have a lower level. Possible ways to change the specific weight are heat, like Mousson guessed, but also addition of sweet water.
* Wiebel discovered the Ainos springs near Drapano, with their brackish water. He guessed that salt water from Argostoli was conducted through underground channels in a depth of 20m and mixed with sweet water before it
* The engineer Marketos discovered in 1940 a characteristic of fast flowing water: water flowing through a tube will produce a lower pressure. This principle is used to build pumps, which work when they are connected to a tap. But the theory that the water was pumped from Argostoli to Karavomilos is not very likely, as the necessary geometric shape of the cavern would have long been destroyed by one of the frequent earthquakes. But this principle explains the relatively low water level at Melissani Cave, as the low pressure in the water lowers the water level.
* An important hint for the modern explanation was the connection to springs at Karavomilos, northwest of Sami, on the other side of the island. This was proven by dyeing experiments, made by Ioannis Petrocheilos and the Austrian hydrogeologists Maurin and Zölt. On the 26-FEB-1963 they made a dyeing experiment by dropping 140kg of uranine, a very intensive green colour, into the Katavothres. The colour arrived at Melissani Cave and the springs at Karavomilos fourteen days later, on 12-MAR-1963.
* In 1989 the French scientist Drogue explained the situation with the existance of a cave system, the different level of the entrances on both sides of the island and the different specific weight of salt and brackish water.
Melissani Cave, Cave of the Nymphs
During the first exploration in 1951, an ancient lamp, which is now on display in the Archaeological Museum of Argostoli, was found there. The excavations of 1962 were made by S. Marinos and produced few but important relics of a former Minoan culture on Cephalonia. Oil lamps, plates and figures show the god Pan and several nymphs. This is, why the cave is sometimes called Cave of the Nymphs. The lake was named after one of the nymphs, the nymph Melissanthi.
Lake Melissani has an absolute invisible specialty, which sounds pretty strange. The lake water is brackish, a mixture of sea water and sweet water. The cave is about 500m from the sea, and the water level is a meter higher than sea level, and the brackish water rises from a 30m deep cave system on one side of the cave and flows silently to the other end of the cave, flowing through narrow crevices into the sea.Here the water from the Katavothres on the other side of the island reappears. This was discovered by dye tracing experiments in 1959.
The cavern, once two big chambers, caved in several thousand years ago. Today the cave has the shape of a B, with two big water filled halls and an island in the middle. The first hall has a big oval opening to the surface, where the sunlight shines in. When the sun is directly overhead, its rays strike the ultramarine water, lighting the cave with blue light. So the best time to visit the cave is on a sunny day at the middle of the day. Nevertheless, a visit at the morning or in the evening has its own atmosphere. The boats seem to hover on a lake of blue light.
Melissani Boat Trip
Melissani Lake The complete tour is done by boat, first making a round trip around the first hall with the hole in the roof. Then the boat passes the island on the opposite wall, where a small channel exists. This channel is too narrow to row, but there is a rope at the wall and the gondolier pulls the boat through. The second hall is a huge cavern with an arched roof, which was also formed by a collapse, but this cave is more to center of the island, and because of the slope of the hill, the overlying rock is still thick enough. The second chamber has numerous big stalactites and stalagmites.
Melissani Cave History
1951 first exploration by Ioannis Petrocheilos, discovery of an ancient lamp on the central hill.
1959 dye tracing experiments by Ioannis Petrocheilos, Maurin, and Zölt revealed the connection to the Katavothres.
1962 excavations on the central hill.
1963 entrance tunnel built, cave opened to the public.
Drogarati Cave – impressive limestone formations
Drogarati’s Cave, which is close to Sami, was discovered 300 years ago, when a part of it was destroyed because of a strong earthquake, and so the entrance was created. The cave’s depth is 60 meters from the ground level, the temperature is 18 C and the humidity is 90%. Initially, the cave was developed and used by the community of Haliotata, under the supervision of the speleologist Mrs. Petrocheilos,and since 1963 it is open for the public.
Speleologists have confirmed that the cave has an extention, that, however is not approachable. That means that the cave is probably connected with other caves in the area. It’s got many stalactites and stalagmites created from the rain, which comes through the rocky level of the cave, it corroses it and deposits its elements on the edge of the stalactites. A stalactite grows one cm every 100 years. Unfortunately, many stalactites are broken, some of them because of the earthquakes, some others because of human lack of sense for the magnificent natural piece of work. Tthe big hall of the cave (900m2), is called “Sala of Apotheosis” because of its perfect acoustics. It’s therefore also used for concerts and other shows.