Lake Tovel

Situated in the Adamello Brenta Nature Park, Lake Tovel occupies a Dolomite basin delimited to the north- west by “marocche”, detritus left behind when the glaciers withdrew. Rio di Santa Maria Flavona, which divides into a large number of springs just before reaching the lake, and Rio Rislà feed the lake while the Torrente Tresenga flows out of it. In November the lake freezes with the ice reaching thicknesses of around half a metre. The average transparency in the summer months is in excess of 10 metres using the Secchi disc. The planktonic fauna is not very rich; the waters are oligotrophic. Amongst the fish species present, the Arctic char deserves a special mention. This fish was mentioned in chronicles dating from the sixteenth century, when it was described as a delicacy served at the tables of the highest-ranking citizens. But Lake Tovel is especially famous for the reddening phenomenon that used to take place in summer, which regularly turned the lake a deep red colour. The reddening was caused by the intense multiplication of a unicellular seaweed belonging to the Peridineum species: the Glenodinium sanguineum March. The bloom is still present but in much smaller quantities. The lake has no longer changed colour, apart from very occasionally, since 1964. Many people believe that the reason for the disappearance of this phenomenon is due to cattle, which provided mineral and nutrients, no longer being grazed here, though more research needs to be carried out to verify this hypothesis.