The lake behind the dam wall has a surface area of about 320 square kilometres (120 sq mi)[1] and is 47 meters deep.

[2] It has over 800 kilometres (500 mi) of shoreline and is South Africa's second biggest dam by area and the fourth largest by volume.

An inflow of over 4,700 cubic metres per second (170,000 cu ft/s) was measured into the Vaal Dam which was already at full capacity due to good rains and it was only through the expert management of the Hydrology staff at DWAF that the maximum flood released from the dam was limited to 2,300 cubic metres per second (81,000 cu ft/s).

Flows above 2,300 cubic metres per second (81,000 cu ft/s) would have caused serious damage downstream of Vaal Dam and the situation during the 1996 flood became extremely tense as the storage in the reservoir peaked at 118.5% of Full Supply Capacity on 19 February 1996 i.e. only 194,000,000 cubic metres (6.9×109 cu ft) of flood absorption capacity remained before the full inflow would have been released causing massive damage.

[3] On 4 May 1948 BOAC introduced Short Solent flying boats on the UK (Southampton) to South Africa (Vaaldam) service.

Due to the large lake size reservoir there is a problem with evaporation, see Sterkfontein Dam for more details.

[6] Egyptian geese and blacksmith lapwing are abundant shore birds, and Caspian terns also occur in large numbers.