PPPs: answer to SA’s droughts

As climate change impacts weather patterns, the private and public sectors should be looking more clsely at partnering on costly projects like reverse osmosis (RO) plants. By Kim Kemp

Peter Shepherd, SRK Consulting partner and principal hydrologist, says, “More could certainly be done in terms of public-private partnerships in the area of RO plants, which are becoming increasingly necessary – as the crippling drought in the Western Cape has shown.

“Private sector investment in these plants could be attracted by government off-take agreements, and this would remove the capital constraints that often delay government projects.”

 He highlighted that climate change was already making the country’s water supply more varied, leading to more frequent droughts and flooding occurring alternately.

 “The appropriate response to this really comes down to better management,” he said. “We need to continually reduce what we use, so that we can cope during those dry periods. At the same time, we need to apply a better understanding and modelling of water flow predictions – so that water transfers can be timeously made between our dams.”

 He also emphasised the urgent need for planned bulk water supply projects – such as the expansion of the Lesotho Highlands Water Project – to be implemented.

 “The authorities have put good plans in place, and these must be prioritised; the implementation has been delayed far too long, and the situation is now urgent,” said Shepherd.

 Another priority was the upgrading of the sewage works at many of the country’s municipalities, as this was affecting both the health of communities and the quality of our rivers.

 “South Africa is still challenged by water that is too dirty – and which is often discharged into our rivers,” he said. “This often comes from sewage plants that are not operating properly, so are not treating sewage to the required level of quality before discharging it.”

 It was important for government to support research and testing of new methodologies for making better use of the country’s water resources, he argued. Innovation in the design and implementation of reticulation systems, for instance, would be a productive area to explore. Certain countries have had some success with using two types of reticulation to end-users: one carrying potable water, and the other non-potable water for purposes like irrigation and industrial processes.

 “Government’s role could also include specifying that new developments install two sets of water pipelines instead of just one,” he said. “These sorts of changes are certainly justified by our water-constrained environment.”

 Despite the many concerns in the sector, there has been considerable progress made in a number of areas in response to South Africa’s perennial challenges of either too much or too little water. Rapid urbanisation continues to place a heavy burden on urban rivers and streams, as development leads to increased run-off and river flooding. Higher energy and more severe flows in rivers lead not only to flooding but to bridge damage, bank erosion and greater deposition of sediment.

 “As SRK, we work with clients to understand these processes and address them in sustainable and cost-effective ways,” he said. “By applying modern methodologies to analyse flow velocities and depths, we can grade the floodline and give a more detailed picture of flood risk potential; this allows us to identify and prioritise the most effective mitigation methods, applying targeted interventions that are more economical for the client.”

 Another important advance in addressing high run-off levels has been to slow down the flow of water at source. Residential developments – with their extensive roof space and paved areas – are now encouraged to establish attenuation ponds to catch water running off from these areas and slow down their entry into the river system.

 “It is important that this is done at the time of building the development, as there is seldom the physical space available for an attenuation pond if it has not been built into the original design,” he said.

 In terms of the problem of water supply in dry times, municipalities often struggle to meet the demand for water from their ever-increasing urban populations. Here, the challenge is to drive home the importance of capturing more of our rainfall run-off so that it can be re-used, either in the home or in industry.

 “It is encouraging to see more people using water tanks to store water that runs off their roofs, as this can be used for irrigation instead of the more expensive and scarce potable water that has been treated by the municipality,” said Shepherd. “Residential complexes are also tending to install borehole water for irrigation, which is a positive trend.”

 Boreholes are also common water sources in smaller towns and rural villages, and SRK is regularly involved in helping clients identify where boreholes may present the most suitable solutions for water supply.

 “We help clients in the design, implementation and management of borehole projects, emphasising sustainability and close monitoring,” he said. “There are also useful technologies available to deal with issues such as high calcium levels in borehole water, which can block reticulation pipes and lead to expensive and disruptive maintenance.”

"Government's role could also include specifying that new developments install two sets of water pipelines intead of just one."




SRK Africa