Highest gravity dam

Constructed in 1950–1961, Grande Dixence, on the river Dixence in Switzerland, is the highest gravity dam, rising 285 m (935 ft). Gravity dams have the shape of a right-angle triangle in vertical cross-section, with a very wide base tapering to a very narrow crest. This maximizes their weight, enabling them to withstand the pressure of vast quantities of water – in the case of Grande Dixence, 400 million cubic metres. Grand Dixence is 200 metres wide at the base, 15 metres at the top and weighs 15,000,000 tonnes (16,535,000 US tons), heavier than the Great Pyramid of Giza in Egypt.

There are four basic designs of dam, chosen according to where they will be sited and the volume of water to be contained and stored. Grande Dixence is located at an altitude of 2,365 metres and is at the heart of a hydroelectric complex that supplies one-fifth of Switzerland’s storable energy. It was built in annual stages because of the relative shortness of the Alpine working season.

Grande Dixence is also the highest concrete dam.