Grande Dixence Dam - Characteristics

Characteristics

The Grande Dixence Dam is a 285 m (935 ft) high, 700 m (2,297 ft) long concrete gravity dam. The dam is 200 m (656 ft) wide at its base and 15 m (49 ft) wide at its crest. The dam's crest reaches an altitude of 2,365 m (7,759 ft). The dam structure contains approximately 6,000,000 m3 (211,888,000 cu ft) of concrete. To secure the dam to the surrounding foundation, a grout curtain surrounds the dam, reaching a depth of 200 m (656 ft) and extending 100 m (328 ft) on each side of the valley.

Although the dam is situated on the relatively small Dixence River, water supplied from other rivers and streams is pumped by the Z’Mutt, Stafel, Ferpècle and Arolla pumping stations. The pumping stations transport the water through 100 km (62 mi) of tunnels into its reservoir, Lac des Dix. Water from the 87 m (285 ft) high Cleuson Dam, located 7 km (4 mi) to the northwest, is also transported from its reservoir, the Lac de Cleuson. Three penstocks transport water from Lac des Dix to the Chandoline, Fionnay, Nendaz and Bieudron power stations, before being discharged into the Rhône River below. All the pumping stations, power stations and dams form the Cleuson-Dixence Complex. Although the complex operates with water being pumped from one reservoir to another, it does not technically qualify as a pumped-storage scheme.

Most of the water comes from glaciers when they melt during the summer. The lake is usually at full capacity by late September, and empties during the winter, eventually reaching its lowest point around April.