Where does Johannesburg get its water
Joburg’s water footprint extends from the Atlantic Ocean on the west coast of Africa to the Indian Ocean on the east coast
Where does Johannesburg get its water
Joburg’s water footprint extends from the Atlantic Ocean on the west coast of Africa to the Indian Ocean on the east coast3rd Mar 2020
Johannesburg is a unique city because it was built without a local water supply. It has become the only major city in the world totally reliant on water sourced from distant rivers and pumped across mountain ranges. This creates a vulnerability that few appreciate when buying or developing real estate.
The city that shouldn’t be
Johannesburg is really a city that shouldn’t be. When gold was discovered in 1886, a dusty mining camp was born. This was just another place name on a map during the gold rush era – Mina Gerais, Brazil (1690); Victoria, Australia (1851); Otago, New Zealand (1861); Pilgrim’s Rest, Mpumalanga (1873); Kalgoorlie, Australia (1885); Klondike, Canada (1896); Nome Alaska (1899). Each of these events created a migration of people from across the world, all hoping to strike it rich, but mostly destitute and desperate. None of these places ever grew to more than a dusty mining town, and this is the difference between them and Johannesburg – the city that shouldn’t be.
Pumping water uphill to power and money
Located in the highveld, with rainfall of around 600mm per annum, the primary gold reef struck to surface at the Witwatersrand Ridge, along Main Reef Road. This is also the continental watershed dividing rivers from the Atlantic and the Indian Ocean, both very far away. The name of the ridge refers to the water cascading from natural springs, the reason for the existence of early hominids, but this is also reflected in the names of mining camps: Doornfontein; Braamfontein; Brakpan; Springs; Randfontein.
After ownership of this resource was determined by the South African War, the triumphant British military established the Rand Water Board, with the sole purpose of accelerating the extraction of gold, and the subsequent repatriation of wealth to England. Rand Water performed hydraulic miracles, pumping water from ever-distant sources. First Fordsburgspruit and Natalspruit, then a spring in Parktown, followed by Doornfontein. Pollution shifted attention to the well fields at Zuurbekom to the west. Still the city grew, so the engineers worked more miracles, building Vaal Barrage in 1923, and the Vaal Dam a decade later – all to slake the thirst of the growing city that shouldn’t be.
No electricity, no water
The Vaal Dam is in an area that receives around 600mm of rain per annum, but it loses three times that amount to natural evaporation off the open surface. This fundamental reality lies at the heart of Johannesburg’s viability as a city after mining ends. More water is lost to evaporation off the surface, for 11 months of the year, than flows in under natural conditions. That’s our nasty little secret. We are vulnerable to the vagaries of the climate.
This means that, to sustain the growing population, water had to be sourced from ever more distant rivers. One of those is the Tugela in KwaZulu-Natal, which was diverted via a complex engineering masterpiece involving four dams and massive pump stations powered by surplus electricity from the Eskom grid. This scheme stores that energy in the Sterkfontein Dam, releasing two-thirds of it to the national grid during peak electricity demand, as the water is released into the Vaal through turbines. This project expanded Johannesburg’s water footprint, by capturing the flow of the Tugela, at the expense of development in KZN. The Sterkfontein Dam provides multi-year strategic storage in a location that has a low loss to evaporation, so its level is more important than that of the Vaal Dam.
But, if there is no electricity, then there is no water released from the Tugela, so there is insufficient for Johannesburg to conduct its normal business if Eskom is distressed. This makes Johannesburg vulnerable.
Importing water from a foreign country
In 1986 the Lesotho Highlands Water Project began. This used the highlands of Lesotho for strategic storage, also to prevent loss to evaporation in the Vaal Dam. Instead of pumping water over the mountains, the engineers drilled a massive tunnel 45 kilometres through the mountain to the Muela power station that generates electricity for Lesotho, followed by a second tunnel of 37 kilometres that delivers the water to the Ash River. It then flows by gravity into the Vaal Dam. This project expands the water footprint of Johannesburg all the way to the Atlantic Ocean on the west coast.
Every drop that sustains Johannesburg today is there thanks to professional planners, capable of projecting into the future and responding timeously to risks that are not yet evident to others, and highly competent engineers that have performed hydraulic miracles by pumping water uphill and through mountains to power and money. Those smart people converted a dusty mining town that was never supposed to survive longer than a few decades into the only major city in the world that is not on a river, lake or the ocean: a city with the biggest artificial forest in the world; a city vulnerable to climate change and the technical capacity of a young nation still finding its way as a democracy; a city dependent on surplus electricity to pump water over mountains; a city that should never have been – but is still standing.