Extended Closure of Lesotho Highlands Water Project Tunnels Due to Technical Challenges

The Lesotho Highlands Development Agency (LHDA), responsible for maintenance on the Lesotho side, encountered several setbacks.

The Department of Water and Sanitation (DWS) has announced an additional three-week extension for the closure of the Lesotho Highlands Water Project (LHWP) water transfer and delivery tunnels due to technical challenges. Originally scheduled from 1 October 2024 to 31 March 2025, the maintenance work has been delayed primarily due to unforeseen complications in the Delivery Tunnel South on the Lesotho side of the project.

Technical Issues and Causes of Delay

The Lesotho Highlands Development Agency (LHDA), responsible for maintenance on the Lesotho side, encountered several setbacks. A significant factor contributing to the delay was a change in the sandblasting technique used within the tunnel. The initial manual approach was replaced with an automated process, but high humidity levels adversely affected the new method, resulting in higher than anticipated seepage inside the tunnel.

In response, the contractor procured additional equipment to manage the seepage challenge more effectively. Despite implementing a recovery plan to accelerate the work, the delay proved unavoidable.

Progress on the South African Side

Meanwhile, maintenance activities overseen by the Trans-Caledon Tunnel Authority (TCTA) on the South African side are proceeding as scheduled and are expected to be completed on time.

Impact on Water Availability

With the Vaal Dam currently at full capacity (101.51%) due to recent above-normal rainfall, the DWS has reassured water users that the extended closure of the LHWP tunnels will not impact the availability of water within the Integrated Vaal River System. Similarly, municipalities along the Liebenbergsvlei River in the Free State will not experience disruptions.

Furthermore, the Sol Plaatje (Saulspoort) Dam, currently at 82.1%, remains at satisfactory levels and can provide water to downstream communities if required. The dam is capable of supplying Bethlehem, Reitz, and Tweeling for up to nine months, exceeding the originally planned six-month LHWP shutdown period.

Future Mitigation Strategies

To prevent further delays, DWS and LHDA have committed to ongoing assessments and the use of enhanced equipment and techniques to expedite the maintenance work. The department has assured stakeholders that all necessary measures are being taken to ensure minimal disruption to water supply services in affected areas.

The DWS will continue to provide updates as the maintenance work progresses.