by Peter Shepherd

Public - Private Partnerships

PPPs can bring heads together to solve both water shortages and floods

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As South Africa’s rapid urbanisation places a growing burden on municipalities, both to supply enough treated water in dry seasons and to control run-off in wet seasons, public-private partnerships (PPPs) will be vital in finding and implementing innovative solutions.

This challenge is not getting easier, as climate change is creating a greater variability in our rainfall patterns.

We have seen more frequent droughts on the one hand, while rainfall in some areas becomes heavier but less frequent. This places a huge strain on the local government’s water infrastructure, as we now have to conserve water more efficiently but at the same time, manage increased run-off and the flooding of rivers.

In the case of severe drought, where high-capital water treatment solutions like reverse osmosis plants may be required, PPPs offer considerable opportunities for viable partnerships. If the government was able to offer the private sector the off-take agreements required to raise capital, for instance, then independent developers may be attracted to invest; this would have the benefit of removing the capital constraints that the government often faces when trying to implement these projects alone.

The good news is that there have been a number of advances made in the field of water management, which can be further leveraged by public-private collaboration and the considered implementation of cost-effective methodologies.

In the case of urban rivers and streams, the densification of residential and commercial developments leaves less space for rainwater to percolate into open ground; the result of more paved or tarred surfaces is greater run-off, leading to higher flow velocities in streams—which, in turn, can erode banks, damage bridges, deposit sediment and even flood the surrounding area. When downpours become heavier—as they have done in many regions—these consequences are exacerbated.

An important way of addressing the growing levels of run-off is to slow down the flow of water at the source. We have seen the benefit of residential developments being designed with attenuation ponds, as these catch water running off the extensive roof space and paved areas—slowing down the water’s entry into the river system. Of course, these interventions need to be carried out at the time of building, as they are difficult to incorporate later; but if these kinds of opportunities were encouraged by the local government, town planners, developers and other stakeholders, the impact would be significant.

The expertise is readily available to take scientific steps towards measurable progress; SRK works with clients to understand these water-related processes at a local level and address them in sustainable and cost-effective ways. We have access to up-to-date methodologies for analysing flow velocities and depths in rivers, for instance, and can provide a detailed picture of flood risk potential. We can, therefore, identify and prioritise the most effective mitigation methods, applying economical and targeted interventions.

These lessons are also relevant to the problem of water supply in dry times, when municipalities often struggle to meet the demand for water from their growing urban populations. One opportunity here is for the public and private sectors to work together to promote the importance of capturing more of our rainfall run-off so that it can be re-used, either in the home or in industry.

Already, there has been progress on this front, with more people using tanks to store water running off their roofs. If residents can store rainwater for use as irrigation in the days between rainfalls, this would help to conserve the more expensive and scarce potable water that has been treated by the municipality. It is also possible for larger users—like residential complexes—to install boreholes for irrigation purposes.

SRK works regularly with clients on identifying where boreholes may present the best solutions for water supply; this option is also a common response to provide water for smaller towns and rural villages. Effective monitoring systems and equipment are vital to the sustainability of these systems, however, as are the right treatment solutions to create an affordable supply of potable water.

The upgrading of sewage works at many municipalities is also a priority, as inadequately treated water was still being discharged into rivers, affecting the health of communities and the river quality. This is often the result of sewage plants that are not operating properly, which, as a technical issue, is not difficult to address.

PPP opportunities also exist for the government to support research and the testing of new methodologies for making better use of the country’s water resources. If South Africa could be more innovative in its design and implementation of reticulation systems, for instance, we might be surprised at the positive results. Some countries have experimented by using two types of reticulation to end-users; one line will carry potable water, while the other carries non-potable water for purposes like irrigation and industrial processes. This has the effect of optimising the use of treated water, so that potable water is not ‘wasted’ on applications like irrigating gardens.

It should also be remembered that bulk water supply projects are vital to supporting and accommodating the country’s continued growth; long lead-time initiatives—such as the expansion of the Lesotho Highlands Water Project—need to be rolled out without further delay. It’s imperative that innovative ways of managing water use are implemented until such bulk water projects come online. 

By Peter Shepherd, partner and principal hydrologist at SRK Consulting (SA)

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