Sterkfontein Dam, Large water reservoir in Harrismith, South Africa

Sterkfontein Dam is a large water reservoir in Harrismith with a massive earth-fill structure that spans the valley. The construction holds back an expansive water surface with steep banks that stretch between mountain slopes.

Construction started in 1969 and the first phase, a 69-metre earthfill embankment without a spillway, was commissioned in 1977. The wall was then raised to 93 metres and the extended dam commissioned in 1980, an 11-year construction period. The site on the Nuwejaarspruit was chosen over the Elands River valley for political reasons, to avoid partly flooding the planned Bantustan of Qwaqwa. The Department of Water Affairs designed and built it.

The dam takes its name from the Sterkfontein farm, where the construction workers' temporary township stood; in Afrikaans sterkfontein means "strong spring". The reservoir is fed mainly by water diverted from the upper Tugela River through the Drakensberg Pumped Storage Scheme, a 1,000 MW scheme moving up to 630 million cubic metres from KwaZulu-Natal, later released to the Vaal Dam via the Wilge River.

The dam is located at an elevation with viewpoints over the water and surrounding landscape, reachable by standard roads. Visitors should note that the area can be windy and paths around the site have varying accessibility depending on your location.

The Driekloof Dam sits inside the Sterkfontein reservoir, a dam within a dam. It is the upper reservoir of the 1,000 MW Drakensberg pumped storage scheme, so it keeps water for pumping even if Sterkfontein runs dry. At full supply, Driekloof is submerged to the top of its spillway.