One of the world's top pumped storage schemes and is situated close to the Oliviershoek Pass. During construction, great care was taken to preserve the environment including regrassing of disturbed areas and the construction of the dams in a way that would attract birds.
Water is pumped from several smaller dams to Kilburn Dam below the wall of the escarpment. It is then pumped up more than 470 metres during off peak demand hours into an upper dam - the Driekloof Dam. At peak demand hours, the pumps that pumped the water turn into turbines that generate electricity as the water flows back down through the galleries.
There are four 250MW reversible pump turbines situated 52 storeys below ground. The pumped water that spills over the upper Driekloof Dam flows into the Sterkfontein Dam and thence to the industrial heartland of South Africa, the Gauteng area. Thus water is pumped from the Indian Ocean catchment to the Atlantic Ocean catchment.
The machine hall, the centre of the scheme is large enough to accommodate a block of flats 13 storeys high with 77 flats per storey. Visitors are recommended to wear flat footwear. No cameras are allowed.