This is the largest natural permanent lake in Slovenia, measuring 318 ha. It is 4100 m long, 1200 m wide and 45 m deep. Located in a glacial hollow, the lake comprises over 100 million cubic metres of water and according to a traditional jest - no more than a bucket if it is large enough. 65 algae species, 8 mollusc species and 5 fish species live in the lake. The main tributary is the Savica that springs at the waterfall under the rock wall of Komarča. Lake water that flows in from numerous other sources is restored three times per year. Water level rises 2 - 3 m at heavy rainfall. In summer, the temperature of the water rises to 22 oC; in winter, Bohinj Lake often freezes.