Zelenci is a nature reserve which is known by a ground springs of Sava
Dolinka River. (Sava River has two sources branches: Sava
Bohinjka and Sava Dolinka). The majority of water flows underground
from Tamar valley where is the first spring - Nadiza - white
waters of Nadiza. Lake of Zelenci has intensive green color (that is
how it got its name - 'zelen = green'). Present lake is situated on the
edge of a swamp which is a remainder of the greater lake which was created
after the last glacial period. In that time torrents from the Karavanke
Alps heaped up rubble which made a barrage for the waters flowing from
the West - so the lake (Podkorelško jezero) was accumulated.
Temperature of the lake is constant (5~8 °C) in all seasons.
Area of the nature reserve is 14 hectares; the deepest part of the
lake is 3 m.