The Cleuson dam is a building built between 1947 and 1959 in the municipality of Nendaz, very close to the ski resort of Siviez or Super-Nendaz. Measuring 87 metres high and more than 400 metres long, it is part of the Grande-Dixence hydroelectric complex.
Le barrage depuis le bisse Vieux au début du val de Nendaz.
- 📍 Location: Nendaz VS
- ⚙️ Initial operation: 1951
- 🔍 Type: Buttresses
- ⛰️ Summit Altitude: 2187m
- 🦅 Heigth: 87m
- 🐘 Thickness (top-bottom): 80m – 3.5m
- 🐍 Length: 420m
- 🌊 Reservoir name: Lake Cleuson
- 🍔 Volume: 20 Millions m³
- ⚪️ Area: 0.5 Km²
- 🏞️ River: Printse
- 🏃 Lake tour: 4km / 1h15
Access to the dam
Access to the dam by car is officially not possible until its crowning but stops shortly after the Super-Nendaz ski resort at the end of the paved road. Two traffic ban signs remind of this. From there, the ascent to the crown of the Cleuson Dam and its turquoise waters takes just over an hour along a small dirt road.
However, the Torpille team noticed that in summer, the cars did not respect the prohibition sign and climbed to the top of the dam. We therefore also recommend doing so rather than walking along the road, which will often be disturbed by the constant stream of cars on a weekend day in good weather. The unpaved road is in good condition but very narrow and care should be taken when crossing with another vehicle or pedestrian.
The visit of the dam is optimal from July to October because it is at this time that the level of the reservoir is the highest and the temperatures the most pleasant. We can try to climb as early as mid-May as La Torpille did, but at that time, access can only be done on foot and parts of the road are still largely snow-covered on the top and the road, which can be dangerous with small children because of the risk of slipping.
The tour of the Cleuson dam can be done in a little more than an hour along a path with no real difference in altitude.
Crowning of the dam
the crowning of the dam is located at an altitude of nearly 2200 meters and allows you to enjoy a beautiful view.
- Downstream side. View of the Val de Nendaz with the ski resort of Super-Nendaz to the Bernese Alps.
- Upstream side. View of Cleuson Lake, the surrounding mountains and the Printse stream that flows into the lake.
The Saint-Barthélémy chapel is built in 1951 during the construction of the dam. The old chapel is built before the 15th century but was swallowed up by Cleuson Lake.
Tortin water intake
On the west side of Cleuson Lake, near the dam, there is a tunnel leading to the lake. It is the water intake collecting water on the other side of the mountain in Tortin.
A pretty picnic area overlooking the lake with fireplaces for BBQs is located very close to the car park at the top of the dam’s crown. All you have to do is follow a small road along the lake for 100 metres. If you wish to barbecue, you should not forget to take wood as the dam area is located at an altitude of 2200 metres above the tree line.
The Cleuson dam is the only large dam in French-speaking Switzerland whose water is not directly turbined by an electricity plant. Indeed, four pumps bring water from the Cleuson dam to the reservoir of the Grande Dixence dam through an underground gallery. The Cleuson Dam watershed is relatively small with an area of 23 km2, of which 7 km2 comes from a collector bringing water from Tortin.
In terms of its shape, contrary to what one might think, it is a buttress dam and not a weight dam as in Salanfe and Grande-Dixence. This is because the spaces between the buttresses are filled with concrete to strengthen its strength in 1950, not to fight against water pressure, but to improve its resistance in the event of bombing. Indeed, the end of construction took place a few years after the end of the Second World War and images of the destruction of some dams during the war, particularly in Germany, are still very much in evidence at that time.
A drone video on the Cleuson dam.