Located about two kilometers from the capital Argostoli, on the coastal road to Lassi, are the island’s most well known sinkholes, known in Greek as katvothres. Seawater enters the sinkholes on the coast and re-emerges at Melisssani Lake and Karavomilo on the other side of the island. The existence of a karstic network across the island was proven in a 1963 experiment, in which Austrian geologists dumped green dye into the sinkholes of Katavothres and traced the course of the disappearing water with the use of radioisotopes.
The watermills were erected by the Englishman Stevens, who was the first to observe this fascinating geological phenomenon. The diagram below illustrates the course of the water:
1. Seawater enters the sinkholes near Argostoli.
2. The water passes beneath the harbour and mountains of the island.
3. Rainwater is added to the seawater.
4. The seawater and rainwater mix together.
5. The brackish waters re-emerge at Melissani Lake and Karavomilo at Sami.