καταβοθρες

Katavothres - Katabothres

Useful Information

the sea water enters an artificial channel.

Location:	Argostoli, Island Kefalonia, Ionian Islands. Follow the coast road to the northern tip of the peninsula. From the center of Argostoli signposted. Alternative route: follow road to airport across peninsula, 200m after sign "Airport 7km" turn right. Follow road to the northern tip of the peninsula.
Open:	no restrictions
Fee:	free
Classification:	Ponor, sink holes.
Dimension:
Guided tours:
Photography:
Accessibility:
Bibliography:	T R Shaw (1992): History of Cave Science, The Exploration and Study of Limestone Caves to 1900, 2nd edition. Sydney: Sydney Speleological Society, p 89 Ernst W. Bauer (1974): The Mysterious World of Caves, Collins, London. pp 108-112
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History

1835	corn mills built by Englishmen.
1868	site visited by Heinrich Schliemann.
1952	last water wheel destroyed by an earthquake.

Description

the water flowing with some speed through the artificial channel sets a water wheel in motion, which symbolizes the historic water mills.

the water wheel does not do any work, but it is still impressive.

The famous Katavothres (=swallow-holes) are an extremely rare geological phenomenon. To be honest, we do not know of any other place on Earth, where this could be found! 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.

the swallow hole unfortunately collects any kind of floating rubbish, especially the empty mineral water bottles.

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.

Our explanation is a bit more detailed, but this natural phenomena is rather difficult to explain. You will find it here.