Making sure we’re wise with water
T ONLY took three years for Jan van Riebeeck and his men to pollute the Cape’s waters. By 1655 Van Riebeeck had to make laws against dumping and water pollution. The sailors who came on ships from Europe said they could smell the city before they could see the mountain.
This early legacy of changing waterscapes has become the norm as we have developed. We have redirected water, sending rivers out of the sunlight and into the concrete underground. We covered our naturally forest-free landscape with colonial trees which drink our water. From the 1940s onwards our rivers were not full enough in the dry season for our large population. So we began the great era of dam building, storing and supplying water across the country.
But by the 1980s, scientists began to notice the strangling effect of these dams on our rivers. Fish couldn’t migrate, banks were collapsing, dams were drying out quickly and water-borne diseases were increasing.
Experts say we are now entering a new water era where these existing problems combine with a new one – we simply do not have enough water.
“Like it or not the human population growth is outstripping supply of various natural resources,” says Anthony Turton, professor at the Centre for Environmental Management, University of the Free State.
The effects go beyond threats to river species or even sporadic municipal water outages. Earlier this year, Minister of Water and Environmental Affairs Edna Molewa said developments in Limpopo and the Eastern Cape had been halted because there was no water to allocate to them.
Turton says lack of water resources is already limiting South Africa’s economic growth and making us less attractive to international investors. No water may also mean we can no longer feed ourselves. Agriculture uses 66 percent of our available water; producing just one calorie of food on average uses one litre of water.
“The big issue ultimately – it’s not about not having water in your tap – it’s about not having enough water to produce your own food,” said Turton.
Climate change is predicted to hit South Africa harder than in other countries because of how we fit into world climate belts.
IHigh temperatures will mean that plants need more water, evaporation rates increase and algal blooms are more likely to destroy dams. According to a World Wide Fund for Nature (WWF) report, more droughts are predicted for the Northern and Western Cape. Gauteng and KwaZulu-Natal will experience flooding and erosion.
“Adapting to climate change is using less more efficiently,” says Christo Marair of the government’s Working for Water programme.
For most South Africans, the source of our water is the tap. But before water enters the municipal machine, it’s interacting with the land and environment it flows through. Research from the CSIR and WWF has shown that just 8 percent of our land area provides us with 50 percent of our water, meaning that degradation of these areas has widespread effects. Only 16 percent of these areas are legally protected.
How we use our land affects our water. Agriculture, hardening of ground with concrete and building dams all change the way water moves.
Battling alien vegetation is at the forefront of trying to get the most out of our water resources. Just 4 percent of South Africa’s utilisable water is being lost as a result of alien species but if we were to leave them unchecked this could grow to 16 percent.
Ultimately, mining remains one of the major threats to water sources. In Mpumalanga, a key water provider, a study last year found that 70 percent of water source areas were under application for future mining.
“Mining is not conducive to water health. No matter what, it will always lead to water degradation,” says CSIR water researcher Jeanne Nel.
Mining in Gauteng has had widespread effects. The Witwatersrand range of rocky hills forms a continental divide, with rivers to the north such as the Crocodile River draining off into the Limpopo River and Indian Ocean and the run-off to the south draining into the Orange River and Atlantic.
“Anything that happens in that concentrated industrial area can have an impact on the full length of the river’s flow,” says Professor George Ekama, Department of Civil Engineering, University of Cape Town.
Pollution, industrial waste and even the effects of acid mine drainage do not stay contained in the Witwatersrand but can spread throughout the water systems.
Acid mine drainage is highly acidic water, usually containing a heavy concentration of metals, sulphates and salts as a consequence of mining activity. Drainage from abandoned underground mine shafts into surface water systems (known as decant) may occur as the mine shafts fill with water.
The short-term intervention on acid mine drainage, which dates back to 1996 but which became a major public concern in 2002, has been extremely successful and has stopped decant in the Gauteng western basin. The water is being neutralised, which means it is safe in that it is not radioactive and does not contain heavy metals, and is being released in rivers.
But this method is not a longterm solution as the water still contains sulphates which are damaging to water infrastructure and stop plants from growing. Possible long-term solutions include trying to return the water to drinking quality through reverse osmosis. The costs of this are potentially as much as R25/litre of treated water and would leave us with a toxic sludge that would need to be stored.