|
|
|
|
The history of the Vaal Dam is quite interesting. The Vaal Dam was built as a joint venture by the former Department of Irrigation (now known as the Department of Water Affairs and Forestry) and Rand Water. The construction of the Vaal Dam commenced during the depression years in the early thirties and was finally completed in 1938. Originally at a height of 54,2 metres upon completion, it was raised to 60,3 metres in the early fifties and to 63,4 metres by 1985. Due to the increase in height, the Vaal Dam’s capacity also increased each time. With a full supply capacity of 994,000,000 cubic metres in 1938, it increased to 2,188,000,000 cubic metres in the fifties and eventually to 2,536,000,000 in the eighties. Something significant about the Vaal Dam is the fact that it can also temporarily hold a further 663,000,000 cubic metres for flood attenuation.
The flood attenuation properties of the Vaal Dam were tested severely on two occasions during its history. The first of these was in February 1996 and the second during December 2010/January 2011. The consequent result of this was severe flooding downstream, causing massive damage to infrastructure.
The Vaal Dam lies on the Vaal River, which is one of South Africa's strongest-flowing rivers. The Vaal Dam has over 800 km of coast line stretching over three provinces, including Gauteng, Mpumalanga, and the Free State. This fact makes the dam quite unique. The Free State is the largest by area, Mpumalanga has a beautiful but rural coastline and the most active by far is the Gauteng coastline. The Vaal Dam covers an area in excess of three hundred square kilometres. It is South Africa's biggest dam by area and the third largest by volume.
Something that few people know about is that the Vaal Dam has its own island (approximately 5km long) that was used during the apartheid era to hold secret meetings.
Due to drought conditions experienced in the early years of the Vaal Dam, it became necessary that a continuous supply of water be maintained in the dam. Two water schemes, the Lesotho Highlands Scheme and the Tugela-Vaal Scheme have ensured that a minimum level of water is maintained at all times in the Vaal Dam. The Lesotho Highlands Water Project pumps water into the system in order to supply water to the people and industrial complex of Gauteng. This water is piped from Lesotho into the Liebenbergsvlei and Wilge Rivers. The Sterkfontein Dam forms part of the Tugela-Vaal water transfer scheme for the interbasin transfer of water from the Thukela River in KwaZulu-Natal to boost the levels in the Vaal River System. Water from the Sterkfontein Dam is released once the Vaal Dam drops to below 16%.
