Grootdraai Dam is a composite structure comprising a central concrete gravity section 360 m long and two earthfill flanks giving a total crest length of 2180 m and a maximum wall height of 42 m above lowest foundation level.
The dam also provides some flood attenuation for Standerton and stores up to 100 million m3/annum pumped into the upper reaches of the Vaal River basin from Heyshope Dam in the Usutu River basin.
The hazard potential of the entire dam construction has been ranked high (3).
During the serious drought of 1983, the water resources in the adjacent Komati River and Usutu River basins were badly depleted, leading to serious concerns that the water supplies to various power stations could be affected.
Although the emergency scheme was never used, it was completed and received an award for the Most Outstanding Civil Engineering Achievement of 1983 from the South African Institute of Civil Engineers.