The British Dam Society
A growing, inclusive and vibrant society; sharing knowledge and improving reservoir safety

About Dams

Back to TypesTypes of Dam - Buttress Dam

Stwlan Dam in Wales

Stwlan Dam in Wales

Buttress dams are made from concrete or masonry. They have a watertight upstream side supported by triangular shaped walls, called buttresses. The buttresses are spaced at intervals on the downstream side. They resist the force of the reservoir water trying to push the dam over.

The buttress dam was developed from the idea of the gravity dam, except that it uses a lot less material due to the clear spaces between the buttresses. Like gravity dams, they are suited to both narrow and wide valleys, and they must be constructed on sound rock.

Since 1945, 14 buttress dams have been constructed in the UK, mainly for hydroelectric schemes in Scotland.