Droughts are a major feature of the climate of South Africa. As a result of the country’s location at the southern tip of Africa between cold and warm sea currents, as well as its topography, South Africa has an extremely variable climate over space and time. Because of these characteristics, the country is considered to have one of the most variable river flow regimes in the world – with drought being one manifestation of this variability.
Along with this climatic variability the country is naturally water scarce. South Africa’s average annual rainfall falls well below the world average of 860 mm a year. Further, the distribution of rain varies widely across the country – generally reducing from east to west, with 65% of the country receiving less than 500 mm of rain a year.
The country’s semi-arid nature results in much water being lost to evaporation, and in many areas evaporation from the surface exceeds the average annual rainfall. It is estimated that less than 9% of the precipitation that falls on the ground eventually finds its way into South Africa’s river systems. This natural water scarcity makes South Africa particularly vulnerable to drought and water stress.
Historically, South Africa has constructed sophisticated bulk water storage and conveyance systems to store water in times of surplus for use in times of need. By the early 2000s, the total storage capacity of the major dams in the country amounted to around 34 million m3 – or 70% of the mean annual runoff from the land surface of the country.
Rising water demand as a result of population growth and socio-economic development is placing pressure on many of these systems. As pointed out by the Second National Water Resource Strategy, most of the economically viable yield from surface water resources has already been fully developed and utilised, and opportunities for developing new and economic dams are few.
The Department of Water and Sanitations Water Reconciliation All Town Study has shown that water resources in 30% of South African towns are already in deficit, with water resource shortages expected in another 13% of towns within the next five years, and a further 12% of towns in the next five to ten years. This situation has the country’s water resource managers walking a constant tightrope between balancing supply and demand, and leaves little room for extreme situations, such as drought.
Climate change is expected to exacerbate the occurrence of drought in South Africa. If we are to expect more intense droughts more frequently, interlude by bouts of high rainfall over short periods, South African water resource managers will have to become smarter about the way they manage and operate the country’s water systems. This is especially true for the country’s municipalities directly responsible for service delivery to communities at the ground level.
It was as a result of an intense drought that the Water Research Commission (WRC) was established decades ago to seek solutions via research to South Africa’s most pressing water questions. The Commission has developed a range of tools and guidelines to assist local authorities to optimise their water systems and reduce water wastage.
These guidelines – a number of which have been included electronically at the back of this publication – cover various topics, such as water conservation and water demand management, operations and maintenance, reducing water losses, and changing behaviours of communities. Guides towards the selection of appropriate alternative water-supply technologies, such as water reclamation and reuse, are also included.
It is hoped that these guidelines will not only add to municipalities’ drought armoury, but assist them on the path towards long-term water security.
For more information on droughts visit our drought portal www.droughtsa.org