How to tackle SA’s sinkholes with better tech
By Bonga Ntuli, irector of the Infrastructure Business Unit at Royal HaskoningDHV Southern Africa. Royal HaskoningDHV is an independent, international engineering and project management consultancy with 140 years of experience and 6 000 colleagues across the globe.

In recent months, six of South Africa’s nine provinces have experienced the most rainfall on record since tracking started in 1921.

This is according to a recent Bloomberg report that cited how the La Niña weather phenomenon is a key factor driving this current trend. However, the report also indicated that climate change could be a bigger trigger when it comes to this exceptionally wet weather.

Just this month, the United Nations (UN) released a report stating that many of the severe impacts of global warming - such as floods and heatwaves - are now “irreversible”. The report highlights how Africa is among the most impacted regions in the world.

Impact on infrastructure

With more extreme wet weather, South African car owners are not only dodging burgeoning potholes, but also a growing number of sinkholes — which can be up to 125m in diameter and pose serious risks to safety.

In fact, there have been over 200 recorded sinkholes in Gauteng over the last five years with the most prominent example of this being a giant sinkhole that appeared along the important N1 highway corridor, in Centurion, Tshwane earlier this year after heavy rains.

Authorities and engineers are currently fixing the Centurion sinkhole. Owing to its size, several lanes of this strip of the N1 have been closed to traffic while engineers have said that repairs could take months.

Dolomitic rock across Gauteng is one reason behind the province’s sinkholes. However, engineers have also said that another factor is leaking water-bearing infrastructure, and poor stormwater management.

Prevention is better than cure

When it comes to managing issues such as poor stormwater drainage and waterlogging, this presents an opportunity to rethink the infrastructure management of our towns and cities.

Much of South Africa’s stormwater, water provision, and sewage infrastructure is decades old, and a lot of it is structurally compromised.

Monitoring this infrastructure is crucial to ensure that any problems are identified as soon as possible and addressed immediately - preferably before bigger issues emerge.

One solution to achieving a better level of monitoring is by using a technology called ‘Digital Twins’. A Digital Twin is a digital replica of physical assets, such as buildings or water pipe networks. By sharing data between the virtual and real-world environment; governments and key stakeholders can pre-empt issues through proactive maintenance. 

In a Digital Twin application, engineers would typically send sensors into a water pipe network to determine a pipe’s location, size, and capacity. Engineers then use this information to build an accurate digital replica of the existing system that can help to predict and manage demand and implement just-in-time maintenance.

Further to this, a Digital Twin’s live data features can help to identify issues more quickly when they happen, and even divert traffic for safety or efficiency reasons if a sinkhole appears in a particular area.

Other practical interventions of Digital Twins technology include using GPS services to reroute traffic around temporary congestion points caused by these sinkholes. All of this can help our towns and cities save money by managing their existing road infrastructure in a far better way.

More cities around the world — such as Singapore — are using Digital Twins extensively for purposes such as these.

But this tech is not just for the First World, and it can be equally applied in developing countries such as South Africa. This could become ever more important in a world where climate change will deliver more unpredictable and extreme weather patterns.