Grootdraai emergency Project

In 1983, a major crisis stared the South African economy in the face: an intense drought which resulted in virtually all the dams supplying the Escom power stations and SASOL being close to empty. This included the Vaal Dam. The latter could, however be supplemented by the Tugela water stored in the Sterkfontein reserve storage. The trouble was that this water was not available to Grootdraai and thus not to the Komati-Usutu link system. Since 1978, river flow had been below average and was exceptionally low in the 81/82 and 82/83 seasons. It was projected that all the dams supplying the Highveld would run dry by September 1983. This threatened the whole country’s electricity supply! High level discussions took place on 21 March 83 between DWA and Escom and on 18 April 1984, the Grootdraai Dam Emergency Supply Scheme was announced by the Minister of Water Affairs. I was personally very involved. The challenge was to get 1 million cubic metres of water per day from the Vaal Dam to Grootdraai. To implement a 90 km, 2m diameter pipeline scheme with high-pressure pumps in the time available was totally unfeasible. The only feasible was a temporary scheme consisting of seven weirs in the Vaal River between the low water level in the Vaal Dam reservoir and Grootdraai. A pumping station downstream of each of these weirs would lift the water, resulting in the river running upstream over a distance of 208 km against a total head of 61,5 m. The lower of these weirs had to be built in the reservoir water of the Vaal Dam. Water Affairs built the weirs and Escom had the pumps flown in from Sweden and installed them. The works from Grootdraai to Trichardtsfontein were also to be extended to be able to transport the full demand of SASOL and all the Escom power stations in the area. Extra pumps and a 26 km pipeline able to carry 8,6 cubic water per second were required. All these works had to be and were completed within four months. Ironically, after operating for a while, the temporary part of the scheme could be abandoned due to heavy rains filling the dams, which even washed away some of the weirs.