Working together towards water security
South Africa has always been challenged by water scarcity and, driven by rapid industrialisation following the discovery of gold in the 19th century, has its economic centre in Gauteng where there is little water locally available.
For those who might not know the history of water since the gold rush in South Africa, maybe I should summarise it.
Gauteng has a population of 15 million and is growing at 4% a year due to its large, sophisticated economy inherited from the mining era.
The Witwatersrand sits on the watershed of two river systems. The springs that supplied the initial sources of water were rapidly exhausted.
The Rand Water Board was established in 1903 to provide ground water to the Witwatersrand from Springs in the east and Randfontein in the west.
Read the latest Simply Green digital magazine below
The construction of the Vaal Dam was started in the early 1930s and was completed in 1938. Water was then pumped uphill by 400m and 80km to the Reef.
We have several other interbasin transfer schemes to get water to our coal-fired power stations and petrochemical complexes in the eastern parts of South Africa. The Orange River transfer scheme provides water to Eastern Cape farmers and Port Elizabeth from the Gariep Dam.
In a nutshell, South Africa has around half the annual rainfall of the global average and much of that water is in areas with relatively low demand.
To add to this, recent studies show around 50% of our rainfall is received over less than 10% of our land mass and that the western parts of the country have been receiving progressively less rain in the winter rainfall areas since the 1980s.
So, what we are experiencing are less predictable rainfalls, probably due to climate change, a rapidly growing population and, to top it all, no area left for damming up of our rivers as we are literally dammed out. The big questions are what can we do about it, what will it cost, and when will our water security be reinstated?
The solution is summarised as: • Reduce • Reuse • Rethink
Reduce is where we reduce our water footprint, inefficiencies in the system and pollution of our water resources which also serves to reduce the available reserves. Our municipalities lose 41% of the water in their delivery networks, where the global average is 25%, and the desirable target is less than 15%. This is a low-hanging option yet to be seized, except in Cape Town which embraced the concept a decade and half ago.
Reuse is where we reuse water for agricultural, commercial, industrial and urban sectors. This means recycling at industrial level and producing non-potable water from, for example, treated sewage for industrial and commercial purposes. Treated sewage has been used for drinking water in the city of Windhoek, Namibia, since 1966 and in Beaufort West and Ballito in the past decade or so with great success.
Rethink: We have to rethink our water resources and preserve what we have by not polluting it with untreated sewage, industrial and agricultural discharges. Then we have to access new sources of water, seeing that our traditional surface and groundwater reserves are fully allocated, with dams losing more and more to evaporation due to rising temperatures.
The last currently feasible option is to desalinate seawater, an infinitely renewable source and an integral part of the natural water cycle. This technology is now mature with prices touching on parity with traditional surface water prices due to energy reductions, engineering improvements and machine learning to optimise plant performances. South Africa launched its water and sanitation strategy last November with a hefty price tag of R900 billion due to at least two decades of underinvestment.
* Benoît le Roy is an environmental alchemist with 40 years of water engineering experience and chief executive and co-founder of the SA Water Chamber which was established to represent the private water infrastructure sector to collaborate with the government to implement the national water and sanitation master plan. This will re-industrialise the water sector, provide skilled jobs and the opportunity to again export water-related products and expertise globally.