Hike around Mauvoisin lake

The Lac de Mauvoisin is a man-made reservoir in a setting of breathtaking natural beauty. The trail begins below the foot of the Mauvoisin dam: at 250 metres, the second-tallest in Switzerland. Illustrated panels show how a network of tunnels deep in the rock connect the reservoir with hydro stations as far away as the floor of the Rhône valley, to maximise electricity generation. Around fifteen double-sided panels are erected on the concrete giant to present thirty large-scale works of art during the summer months.

The trail soon disappears into an opening in the mountainside and follows a former construction gallery for 392 metres through the rock, decorated with photos telling the story of the dam. Walkers emerge at the top of the structure – in summer an open-air art gallery featuring large-format photographs by international artists.

Today’s reservoir is man-made, but lakes have formed here naturally in the past – with catastrophic results. In 1818, ice falls from the Glacier du Giétro to the east had blocked the river, eventually creating a lake 200 m long and 60 m deep. Attempts to drain it failed, and on 16 June the ice dam gave way. A wall of water devastated the valley, killing more than 40 people; the subsequent investigations mark the birth of glaciology.

The trail leads high above the eastern shores of the reservoir and deep into the heart of a vast wilderness: the Haut Val de Bagnes nature reserve, the second largest in Switzerland (150 sq. km). An exceptional variety of flora includes rare alpine flowers as well as chamois, marmots and ibex.

The southernmost point of the trail is the Cabane de Chanrion, offering a welcoming stop for refreshments. From here, the trail leads along the western shores of the reservoir back to the dam and the start of the walk.

Highlights

• Barrage de Mauvoisin – 2nd tallest dam in Switzerland
• Dramatic ascent to the summit through former construction tunnels
• Haut Val de Bagnes wilderness – Switzerland’s 2nd largest nature reserve