Progress is being made on the maintenance and repair of the Lesotho Highlands water tunnel, which was shut down more than a month ago to undertake the critical work that will ensure longevity of the infrastructure.

Since the total shutdown on October 1, for a duration of six months, the tunnel, which transfers a contracted 780-million cubic metres of water a year into South Africa, has been emptied of water and general inspections were conducted – essential activities that were required before repair works started on November 1.

The Trans Caledon Tunnel Authority (TCTA), which is responsible for implementing the maintenance in conjunction with the Lesotho Highlands Development Agency (LHDA), appointed a contractor to execute maintenance operations for the 38 km of the Lesotho Highlands tunnel project on the South African side.

The LHDA is focusing on the transfer tunnels at the Muela hydropower station in Lesotho.

Both the implementing agents will conduct the maintenance work concurrently until completion on March 31, 2025.

Maintenance work on the tunnel takes place every five years to ensure longevity, reliability and integrity of the tunnel for continuous transfer of water from the highlands of Lesotho into South Africa.

TCTA CEO Percy Sechemane said that this maintenance period is the longest to be undertaken yet since the tunnel came into operation in 1998. As the infrastructure was relatively new, it did not need extensive maintenance until now.

The tunnel is still in good condition and the TCTA does not foresee any challenges in meeting the targeted completion dates, he told Engineering News during a media tour of the dewatered tunnel in the Ash River Outfall, in Clarens, Free State.

TCTA project management and implementation executive manager Johannes Mavuso explained that the repair work on the tunnel started on November 1 and is scheduled to end on February 28, 2025, to enable the release of water from Lesotho to reach South Africa by March 31.

The work underway includes various technical, civil, mechanical, and electrical engineering work, as well as sand sandblasting, including recoating of steel lining of the tunnel and removing corrosion that has built up for many years. The repair work will also be done on the precast concrete segment lining within the tunnel.

During the media tour, Water and Sanitation Deputy Ministers David Mahlobo and Sello Seitlholo expressed satisfaction with the progress made.

“The maintenance will enable the parties to sweat the asset for the next 20 years and guarantee assurance of supply. It is necessary inconvenience, a small pain over a short period,” said Mahlobo, commending the progress made regarding the maintenance work.

Water from the Katse dam in Lesotho flows through the tunnels into the Ash and Liebenbergsvlei rivers in the Free State, then into the Wilge river and eventually spills into the Vaal dam. The Ash and Liebenbergsvlei rivers supply water to the local municipalities of Dihlabeng, Nketoana and Mafube in the Free State, as well as to the agricultural irrigators in the area.

“I must add that we are proud of the TCTA, which has employed South African expertise in maintenance operations of this nature, both engineering and technical in nature. We are confident that the operations will take place as planned until the tunnel is reopened again next year in March,” he added.

While there are some risks that could potentially delay the project, including rain, poor performance by contractors and local labour expectations, Mavuso said that work is being performed in a controlled environment in tunnels, with only work on the Ash river expected to be impacted by rain, while several other control measures are in place, including a war room to monitor progress, daily progress meetings with contractors, weekly progress updates against baselines schedules, monitoring of deviations to schedules and implementing recovery plans if required, monthly interface meetings between TCTA and LHDA and quality assurance provided on sites.

The war room, which includes the Free State Department of Cooperative Governance and Traditional Affairs, TCTA and municipal managers from the Mafube, Nketoana, Setsoto, Dihlabeng and Mantsopa local municipalities, keeps track of the developments or progress on the maintenance work done on the tunnel.

The war room is also constantly taking stock on progress of municipalities on dam levels, leak repairs, construction of water infrastructure and drilling of boreholes to ensure sustainable water supply to communities, particularly those that are affected by the tunnel shutdown.

“There was proper planning before the tunnel shutdown and the assessment was made for the affected municipalities in the Free State as well as in Gauteng province,” Mahlobo commented.

About 700-million cubic metres of water had been transferred in anticipation of the closure, with 2024’s balance of 80-million cubic metres of water to be transferred once maintenance has been completed.

This enabled South Africa to receive most of its yearly water deliveries, ensuring that both the water supply and the royalties revenue that Lesotho receives from those deliveries are minimally impacted.

Mahlobo further assured that there will be enough water supply until the completion of the maintenance operations – with a three-month buffer beyond the initial six months – with Sterkfontein dam on standby to release water into the Vaal dam should it reach a low level of 18%.

“There are contingency measures in place to ensure that the Vaal dam, which mainly supplies Gauteng, will be topped up from other storage dams within the Integrated Vaal River System (IVRS), if it reaches critically low levels.”

The DWS-managed IVRS, which comprises 14 interconnected dams through a system of rivers, canals, tunnels, pipelines and pump stations, has enough water for the duration of the maintenance period, and, if needed, water can be transferred from one part of the system to another.

The IVRS includes the Vaal, Sterkfontein, Grootdraai and Bloemhof dams, besides others, which are augmented by the Katse and Mohale dams in Lesotho.

Seitlholo said that, although the municipalities are taking strain, the Department of Water and Sanitation (DWS) will continue to provide support to ensure sustainable water supply to communities. He has, however, encouraged municipalities to be responsive to issues of water supply and also address the problem of water losses owing to illegal connections and aging infrastructure.

“Issues of water supply challenges in municipalities should receive urgent attention and there should be continuous conversations about them. Loss of water to the ground before it even reaches our communities needs to be tackled in most municipalities because it results in unsustainable service delivery, particularly that we are a water-scarce country.

“If we do not fix local government, there will be more problems that will continue to persist in the country,” he warned.

Free State acting Premier Jabu Mbalula acknowledged the support that the province has been given by the DWS in matters of water security within the province.

“Today, we were exposed to the beauty of engineering and through our intergovernmental relations, we are certain that Free State province will not suffer in terms of sustainable water supply to our communities.”

“As Free State we reiterate the call to our communities to continue to use water sparingly, as we all know that water is a scarce resource. We are happy with the progress of the maintenance work which had minimal effect on water supply to our residents in the Free State,” he said.