The sixteen lakes are separated into an upper and lower cluster formed by runoff from the mountains, descending from an altitude of 636 to 503 m (2,087 to 1,650 ft) over a distance of some eight km, aligned in a south-north direction.
Currently, 16 lakes can be seen from the surface. These lakes are a result of the confluence of several small rivers and subterranean karst rivers. The lakes are all interconnected and follow the water flow. They are separated by natural dams of travertine, which is deposited by the action of moss, algae, and bacteria. The particularly sensitive travertine barriers are the result of an interplay between water, air and plants. The encrusted plants and bacteria accumulate on top of each other, forming travertine barriers which grow at the rate of about 1 cm (0.4 in) per year.
