Thórisvatn Lake

Þórisvatn is the largest lake of Iceland, situated at the south end of Sprengisandur highland road within the highlands of Iceland.It is a reservoir of a surface about 88 km2 and uses the energy of the river Þjórsá, which comes down from the glacier Hofsjökull. Here in the south, it is exploited in a power station. It is like other Icelandic lakes, which are mostly glacial lakes or volcanic lakes.

The lake grew from about 70 km² to 86 km² with the construction of the power station and was previously only the second largest lake in the country.

Source: Wikipedia