People still remember Lago di Tovel as the red lake. Until 1964, in hot summers, its waters really did turn blood red with the bloom of a microscopic alga, Tovellia sanguinea, which coloured the most sheltered bay and drew the curious from half of Europe. Then the phenomenon stopped, almost certainly because of the drop in nutrients coming down from the high pastures, and the red never came back. What remains is still a spectacle: emerald green water, clear for several metres down, framed by scree and woodland, with the walls of the Brenta closing off the horizon.
The lake sits at 1,178 metres, at the far end of the Val di Tovel, a side valley climbing above the Val di Non, in the heart of the Adamello Brenta Nature Park. It is one of the largest natural lakes in Trentino and one of the most untouched: no bathing resorts, no motors, just a trail that circles it in a scant hour of easy walking, with little beaches of white pebbles where you can stop and watch the water change colour with the light.
Precisely to protect it, car access is restricted at the height of summer: when the car parks up the valley are full, the road closes and you go up on the park shuttle from the valley floor. It pays to arrive early in the morning, or simply take the bus and be done with it. Out of season, in autumn above all, the valley empties and the blazing beech trees around the lake give you what may be the finest days of the year.
On the shore you'll find the Casa del Parco Lago Rosso, a small visitor centre that tells the story of the alga and the valley's environment, perfect if you have kids along. The Val di Tovel is also bear country: the brown bear's return to Trentino came through these forests, and the panels along the trails explain how to behave. That's no reason to stay away, quite the opposite: it's the sign that you are walking in one of the wildest valleys in the Brenta Dolomites.
Frequently asked questions
Why did Lago di Tovel turn red?
Because of the summer bloom of a microscopic alga, Tovellia sanguinea, which in hot summers stained the lake's most sheltered bay red. The phenomenon stopped in 1964, in all likelihood because of the drop in nutrients linked to reduced grazing at altitude, and it has never happened since.
How do you get to Lago di Tovel?
You drive up from the Val di Non along the Val di Tovel road to the car parks near the lake. At the height of summer access is restricted: when the spaces run out the road closes and you continue on the Adamello Brenta Park shuttle from the valley floor. Best to arrive early in the morning.
Can you walk around the lake?
Yes, an easy, well-marked trail circles the whole lake in about an hour of walking, with almost no climbing. It works for families with children too, with pebble beaches and viewpoints to stop at along the shore.
Can you swim in Lago di Tovel?
The lake is a protected environment inside the Adamello Brenta Nature Park and swimming is not allowed. The water, which is largely spring-fed, stays freezing cold even at the height of summer anyway. You enjoy the lake from its shores, which is the best way to respect it.