Each year it holds back over 400 million cubic metres of water, a capacity achieved by the use of no less than 6 million cubic metres of concrete in its construction. With exactly the same quantity of concrete, it would be possible to build a wall 1.5 metres high and 10 centimetres wide, running all the way round the equator!
At its base, the dam is 200 metres wide. At its peak, it narrows down to 15 metres. The impermeability of the foundations is ensured by the grout curtain which surrounds the dam down to a depth of 200 m. It extends 100 m into the riverbank on each side of the valley. The wall itself consists of 16 metre thick concrete blocks with special joints that ensure maximum -cohesion, resistance and impermeability.
Any movement of the Grande Dixence dam and the condition of the surrounding cliffs are constantly monitored. Watchmen regularly check the 32 kilometres of tunnels and wells inside the dam. They also monitor the exterior of the dam and the banks to immediately identify any new developments.
| Construction | 1951 – 1961 |
| Commissioning | from 1961 |
| Height | 285 m |
| Crest | 15 m wide, 700 m from one bank to the other |
| Volume of concrete | 5 960 000 m3 |
| Length of visitor tunnels | 15 200 m |
| Length of injection well | 14 500 m |
| Volume of reservoir | 400 000 000 m3 |
| Reservoir surface area | 4,04 km2 |
| Length of reservoir | 5,3 km |
| Length of meltwater, drainage and thalweg tunnels | 2160 m |