The main water supply to South Africa’s economic hub, greater Johannesburg in the Gauteng province, and to the country’s breadbasket in the Free State, is scheduled to be cut off for six months. Maintenance work on the 37 kilometre Lesotho Highlands Water Project tunnel is due to begin in October 2024. Ifedotun Victor Aina, a senior researcher at the Water and Production Economics Research Unit at the University of Cape Town, takes a critical look at who could be affected by the shutdown and what might happen.

What is the Lesotho Highlands Water Project? Why is it so important?

It is a large-scale water supply scheme in which water is diverted from the highlands of Lesotho to South Africa’s Free State and the greater Johannesburg area. The project is designed to transfer over 1.27-billion cubic metres of water annually from Lesotho to South Africa, providing a vital water supply to the Gauteng region’s cities and industries. To visualise this amount, imagine about 508 000 Olympic-sized swimming pools filled to the brim every year.

Launched in January 1998, it was developed in partnership with the governments of Lesotho and South Africa. It involved the construction of a series of dams, reservoirs and tunnels throughout Lesotho. These all deliver water to the Vaal River system in South Africa.

The Lesotho Highlands Water Project is a lifeline to millions of South Africans. For example, it:

• satisfies 60% of Gauteng’s water demand

• supplies the irrigation water for commercial farms

• supplies water to regions with irregular rainfall patterns and frequent drought

• plays a role in public health by delivering clean water to millions of people

• contributes to environmental conservation.

The influx of fresh water helps reduce the acidity of the Vaal River reservoir, which has long been polluted by industrial activity, sewage and gold mines.

The project is also a crucial water source for the country’s industrial heartland. Any slowdown to water-intensive industries would have economic repercussions.

What’s behind the planned tunnel shutdown?

The tunnels need essential and critical maintenance and repairs. This is due to take place between 1 October 2024 and 31 March 2025.

The work will be conducted in phases. In the first month, the tunnels will be emptied in preparation for four months of maintenance and repairs. The last month will be taken up by inspections and refilling the tunnels with water.

This maintenance is critical for ensuring the integrity of the tunnel systems. It will allow technicians and engineers to check the tunnel thoroughly, fixing any problems they find, and making detailed reports. They cannot do this when it is full of water. They will repair the steel walls that were found to be in urgent need of attention during the last maintenance shutdown in 2019.

The temporary shutdown will be managed by the Lesotho Highlands Water Commission, a joint governance body between South Africa and Lesotho.

What will the impact be?

The impact on residential and agricultural users could be significant.

Firstly, it could exacerbate current water scarcity that’s affecting millions of people in Gauteng. The combination of limited water resources, population growth, climate variability and inefficient water management has led to a situation where water scarcity is a chronic and widespread problem.

Residential areas that rely on the tunnels for their water may experience water restrictions. These include Mafube, Nketoana and Dihlabeng in the Free State and Gauteng provinces. There might also be reduced water pressure, and the periods during which water is available may be shortened.

Secondly, depending on the severity of the water shortage, people may need to rely on alternative water sources such as underground water and bottled water, which cost more.

Thirdly, people’s water consumption habits are likely to change. Water may be restricted and residents may need to plan their consumption accordingly.

Fourth, severe water restrictions could lead to people seeking out water from alternative sources, like streams or boreholes, which could cause health problems.

Lastly, agriculture depends heavily on consistent and reliable water sources for irrigation, livestock watering and other farming activities. The shutdown may result in reduced agricultural productivity, crop failure, and financial losses for farmers who rely on the Lesotho Highlands Water Project. This could affect food security, livelihoods, and the overall economy of affected areas.

The tunnel closure might also lead to a series of unexpected issues such as disruptions to hospitals, sanitation systems, and other essential services that rely heavily on a consistent water supply. If business experiences an intermittent water supply, this could have a ripple effect with production slowdowns in one sector leading to shortages and price hikes in others.

If people start extracting groundwater, this could put additional strain on already stressed ecosystems. Factors like unexpected low rainfall or technical problems with backup systems could make the situation worse.

Can anything be done to soften the impact?

Proactive planning and mitigation measures could help. Public awareness campaigns about the need to save water should be carried out well in advance of the shutdown. Creating awareness that there will be less water may significantly reduce water demand during the closure. The government could also offer financial incentives for people to adopt water-efficient appliances and irrigation practices.

The Department of Water and Sanitation must work with the affected municipalities on wide ranging plans to maintain a continual water supply for the six months. This must include back up plans that can immediately come into play in severe scenarios. The government has said that plans are being made, but no concrete information has been released.

Overall, the impact of the tunnel closure will be determined by three key factors:

• government’s strategy to alleviate the water shortage

• individuals’ efforts to save water

• the availability of alternative water sources.

Effective planning, responsible water use and innovative solutions will be needed.

Written by Ifedotun Aina, Senior Researcher and Postdoctoral Research Fellow in the Water and Production Economics Research Unit, University of Cape Town

This article is republished from The Conversation under a Creative Commons license. Read the original article.