Date contructed:
Water uses:
The 50 m high Knellpoort Dam was completed in 1988. It was the first arch gravity Roller Compacted Concrete (RCC) dam in the world and comprises almost 64 600 m3 rollcrete and 14 200 m3 concrete with a gross storage capacity of 137 million m3. In order to prevent similar siltation problems to those experienced at the Welbedacht Dam, the Knellpoort Dam functions as an off-channel storage dam with a relatively small catchment area of only 798 km2 and corresponding MAR of approximately 20 million m3/a . Water from the Caledon River is pumped to Knellpoort Dam from the Tienfontein Pumping Station via a 2 km long canal which is equipped with a silt trap to reduce siltation in the main reservoir. The Knellpoort Dam is currently used to supplement the water in the Welbedacht Dam for abstraction to Bloemfontein via the Caledon Bloemfontein pipeline. As the Bloemfontein demands increase, however, the capacity of the pipeline will become the limiting factor. Water will then be transferred directly from the Knellpoort Dam into the Rustfontein Dam catchment via the Novo Transfer Scheme which is currently in the detailed design stage (Ref.1)
