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Back to TypesTypes of Dam - Gravity Dam

Claerwen Dam in Wales

Claerwen Dam in Wales

A gravity dam is made from concrete or masonry, or sometimes both. It is called a gravity dam because gravity holds it down to the ground stopping the water in the reservoir pushing it over.

Cross-section through gravity dam

Cross-section through gravity dam

A cross-section (or slice) through a gravity dam will usually look roughly triangular.

Gravity dams are suited to sites with either wide or narrow valleys, but they do need to be built on sound rock.

There are more than 250 gravity dams in Britain. Masonry was used in many early dams, as far back as the 17th Century. However, concrete became more common from about 1900.