Lake Ganna

Lake Ganna is a small basin within Valganna, a U-shaped valley predominantly formed of relatively impermeable types of rock, on which sediments based on peat and clay loam accumulated.Even though it is at an altitude of just 452 metres above sea level, it shows characteristics typical of mountain lakes at about 1000 metres height. It has a surface area of about 6 hectares, a perimeter of about 1 km, an average depth of 2 m and a maximum depth of 4 m. The time over which the water in the lake is entirely renewed is relatively short at just over one month, and its principal supply is the river Margorabbia. The Lake Ganna area is subject to high rainfall and low temperatures, which have a significant effect on the flora and fauna.

Because there are no industrial plants, and the urban settlements within the lake's catchment area are small, the lake's water is exceptionally clean.