Engavatnet is a mysterious lake that suddenly disappears underground. The water has no surface outlet but is connected to an underground area with caves and times.
The seabed in Engavatnet consists of clay that usually closes the holes of the cave systems. When the groundwater level drops, the camp can suddenly loosen. The water in the sea then disappears into the cave systems very quickly while the fish often remain on the seabed. Usually the water returns after a few weeks when the groundwater level rises again.
The special landscape around Engavatnet is called karst and is formed when calcareous calcareous ground, buried and cracked on the surface. The result is caves, underground times and pits in the surface. Northwest of Engavatnet lies Karstgrotta Aunhola. The furthest in the cave probably comes from the underground outlet to Engavatnet.