Maintenance Work At The Lesotho Highlands Water Project Tunnel Complete, Water Refilling Process Is Underway.
The maintenance work of the Lesotho Highlands Water Project (LHWP) water transfer and delivery tunnels have been completed and the process of refilling the tunnels with water is currently underway, with water from Lesotho arriving this morning at the Little Caledon tunnel and is expected to arrive at the Ash River Outfall Works, in Clarens Free State on 22 May 2025.
LHWP tunnel system was closed on 1 October 2024 for a period of six months for a joint maintenance operation undertaken by Trans Caledon Tunnel Authority (TCTA) on a Delivery Tunnel North within South Africa, and the Lesotho Highlands Development Agency (LHDA) on the Transfer and Delivery South Tunnels in Lesotho. The tunnel was scheduled to reopen in March this year, but due to maintenance work delays experienced in the Delivery Tunnel South on the side of Lesotho, the closure was extended to allow the maintenance work to be completed. In South Africa, the maintenance work was on schedule and was finalised on 19 March 2025.

The filling of the tunnel started with the filling of Muela dam in Lesotho between 13 – 17 May 2025, and the Department of Water and Sanitation (DWS) and the TCTA are closely monitoring the flow of water filling of the Delivery Tunnel North in South Africa.
Water has subsequently reached the Little Caledon tunnel this morning and is expected to reach Ash River Outfall on 22 May 2025. The tunnel plays a crucial role in supplying water to Free State and Gauteng provinces and supplies more than 400 million cubic meters (mᵌ) of water to the Vaal Dam annually. The Ministry of Water and Sanitation is expected to witness the tunnel water outflow at the Ash River Outfall Works on Sunday, 25 May 2025 after more than 7 months of the tunnel closure due to maintenance.