Družmirje Lake

Družmirje Lake or Šoštanj Lake (360 m a.s.l.) is an artificial lake in Slovenia belonging to the group of Saleska lakes. It got its name from the nearby settlement of Družmirje, whose surroundings filled with water due to coal extraction in the Velenje coal mine. The lake is a flow-through lake; the water in it is exchanged two to four times a year.
Družmirje Lake has two basins, one not exceeding a depth of 5 m, the other as much as 87 m, and thus Družmirje is considered the deepest lake in Slovenia, not counting the depth of the siphon of Divje Lake. Otherwise it has an average depth of 24 m. The lake's inflow is the Velunja stream. It is predominantly polluted.

Source: Wikipedia