The Katse Dam, part of the Lesotho Highlands Water Project. Maintenance on the Lesotho Highlands Water Project starts next month and will last until March 2025. (Photo by Adrian Greeman/Construction Photography/Avalon/Getty Images)
Maintenance on the Lesotho Highlands Water Project starts next month and will last until March 2025, but the effect of the tunnel closure on the Integrated Vaal Reservoir System (IVRS) will be minimal, because most dams are relatively full, the department of water and sanitation has said.
But consumers are urged to use water sparingly, said department spokesperson Mandla Mathebula.
The reservoir system consists of 14 interconnected dams including the Katse and Mohale dams in Lesotho and the Vaal, Sterkfontein, Grootdraai and Bloemhof dams in South Africa.
“The dams are linked to each other by a system of rivers, canals, tunnels, pipelines and pump stations. [The department] manages the IVRS as a system, in which water can be transferred from one part of the system to another, as and when required,” said Mathebula.
A statement from the department said the closure of the tunnel for maintenance “will not result in any disruption of water supply to Rand Water, and to the municipalities in Gauteng and other provinces which are customers of Rand Water”.
But there are concerns for the Free State, Mpumalanga, KwaZulu-Natal and North West, according to WaterCAN, a network of citizen science activists advocating for clean, safe and sustainable water supply.
“These provinces and many of the municipalities until now have performed very poorly in terms of water and sanitation, so it is hard to have confidence that things will be managed to mitigate people having no water,” WaterCAN executive manager Ferrial Adam said.
“And this is a very worrying issue. The [water and sanitation] minister has said that the Free State for example is running behind in preparing for the maintenance.”
Mathebula said contingencies such as drilling boreholes in vulnerable towns to augment water supply were in place for certain areas.
“In the Free State province, the affected municipalities are Dihlabeng local municipality (specifically the town of Clarens and surrounding farms), Nketoana local municipality (specifically Reitz), and Mafube local municipality (specifically Tweeling),” he said.
“A risk assessment was conducted to determine the impact of the shutdown on water availability to the affected towns and surrounding farms.”
Adam called for “very clear communication every week on the state of maintenance and areas being affected by no water”.
“This also needs to be a pre-emptive communication and not wait for problems to happen and then only communication is received. Government needs to put in place a clear method that allows people to report no water so that they can be provided with water timeously. It is during this time that the government needs to be visible and on the ground,” she said.
“There must be clear details of alternative water sources and municipalities must assist vulnerable people and communities to get water — if supplying water tanks they must be vetted and communications with time tables provided to people for when tanks will be in areas affected.”
Adam said another concern was the risk of corruption, with some people being made to pay for water from tankers.
Both Adam and Mathebula said it was important to plan the maintenance for summer because the rainy season would help in managing any shortfall. In the worst-case scenario the Sterkfontein Dam, which is full, will act as a reserve for the Vaal Dam.
“The standard operating rule is that Sterkfontein Dam releases water to the Vaal Dam when the Vaal Dam reaches a level below 18%. In the unlikely event that the Vaal Dam reaches 18%, Sterkfontein Dam will be used to top up the Vaal Dam,” Mathebula said.
The maintenance work is being overseen by the Lesotho Highlands Water Commission, a joint governance body of South Africa and Lesotho, the department of water and sanitation said.
The work will include grit-blasting the steel-lined section around the circumference of the tunnel and re-applying corrosion protection on the lining. There will also be other maintenance that should protect the infrastructure for “20 to 30 years”.
“The six-month period required to conduct maintenance is thus crucial to avoid any catastrophic event which may result from a lack of maintenance,” the department added.