Taking drought on board


Roads aren’t exactly an endangered species, but certainly the range of changes to which they must adapt is increasing. Heavy trucks have meant that road surfaces had to become more resilient; the impending future of electric cars will also mean road adaptation – as will climate change, which is upon us.

Very few sensible people these days question the reality of climate change. In South Africa, temperatures have been rising consistently for almost 70 years and continue to do so – going up by some 2% in coastal regions and about 4% inland by 2050. And double that by the end of the century. Clearly that has an effect on what we

Aproduce – as well as where we produce it, how we produce it and at what cost. As rain patterns change, fruit and cereal crops from winter-rainfall areas will be affected, as will maize in summer-rainfall areas. Food security will become an issue.

Part of climate change is that in very many areas of the country, rainfall will diminish and drought or near-drought conditions will increase. The dire situation in the Western Cape should remind us that water is a rare and diminishing commodity – and that we should take it seriously and work with it as a fact.

SANRAL does take it as fact and has fully taken onboard the implications of climate change in everything it does, not only where its own staff is concerned but also in the way it builds roads.

Extreme heat or too much water can have devastating effects, but the main concern now is how to manage our scarce water resources.

SANRAL, together with other institutions, has come up with three different approaches to unlock new and long-term sources of water. These include water augmentation, material modification and water conservation, as well the desalination of seawater.

Water augmentation is exactly what it sounds like – increasing groundwater supplies through acid mine drainage, shale gas fracking and deep-seated geothermal water. Essentially, this means adding water into the ground using recharge boreholes, which then reaches the water table.

Material modification entails the use and modification of construction

It is now standard practice for SANRAL to expect its contracting partners to find alternative sources of water and use the bare minimum of municipal water during construction.

Yes, drought does affect roads and road construction. In California, it is accepted that roads during a long-term drought will warp, buckle and crack. In Mississippi, the concern is about the shrinkage of underlying road-bed materials and in South Africa, the shortage of water poses a hazard to construction.

materials that use minimal amounts of water, while the desalination of seawater simply means taking dissolved salts out of the water to make it potable. The advantages of taking these preemptive steps are clear: no construction delays during droughts or water shortages, because there is secure

ground water supply for contractors as well as longer-term water security for communities.

It is now standard practice for SANRAL to expect its contracting partners to find alternative sources of water and use the bare minimum of municipal water during construction, while at the same time maintaining the highest standards of quality and safety on the country’s road network.

This means that any construction methods used must take into account the changing availability of water. For example, underlying road-bed materials have to be selected to minimise warping and cracking; it might mean providing wider shoulders to support the edge of the pavement structure and possibly provide gentle side slopes that are less prone to sliding.

Individuals and companies all have to adapt. SANRAL’s offices are already all eco-friendly. Its Western Cape building took additional measures when the drought hit – toilets were connected to rainwater tanks and when the rainwater ran out, they were filled with recycled and treated effluent water; fresh water supply to hand basins has largely been cut off and the irrigation system outside the building also uses treated effluent water.

Climate change – and drought – should now be a permanent part of future planning for all companies. The drought in the Western Cape should be a wake-up call for everybody.

Mpati Makoa is
SANRAL’s Environmental Manager
Building South Africa through better roads