Following two months of planned maintenance shutdown of the transfer and delivery tunnels, the Lesotho Highlands Development Authority (LHDA) jointly with her sister organization from South Africa, the Trans Caledon Tunnel Authority (TCTA) have successfully completed routine inspection and maintenance works, which commenced on the 1st October 2019.

The inspection and maintenance was a follow up on works undertaken in 2012. The focus was to ensure unimpeded performance of the tunnels in order to ensure sustainable operations of all electro-mechanical components of the Project from the Katse Intake Tower, through the ‘Muela Hydropower Station and the Ash River Outfall in Clarens, South Africa.
According to Mr. Reentseng Molapo, the LHDA’s Divisional Manager-Development and Operations (DM DOD), the current works are undertaken to ensure that the LHWP is able to deliver on its mandate of generating hydropower for Lesotho and transferring high quality water to South Africa. Molapo adds that; to gain access into the tunnels by maintenance workers, water transfer and electricity generation were stopped, and water was gradually taken out from the tunnels and ‘Muela Dam. Thereafter maintenance works commenced from 7th October 2019 to 15th November 2019. This therefore means that during this period Lesotho did not generate her own electricity but relied on supply from ESKOM in South Africa and the Electricidade de Mozambique (EDM) in Mozambique.

Works carried out during the two months included inspection of the condition of the tunnels and ‘Muela Hydropower station surge shaft, installation of new state of the art water flow meters at Ngoajane flow measuring station, corrosion protection repair works on the tunnels steel linings, replacement of the valve at the ‘Muela Hydropower Station bypass and other annual maintenance works of the hydropower plant.

From 18th November 2019, the tunnels and ‘Muela Dam were slowly filled with water to get ready to start transferring water and electricity generation on the 1st December 2019.

In preparation for the outage, Molapo explains that a number of contracts were procured. Furthermore, several technical meetings and training sessions were held on safety in tunnels and use of portable breathing devices in cases where ventilation within the tunnel was insufficient.

The Lesotho Highlands Water Project (LHWP) is a multi-phased, multi-billion Maloti/Rand project between the governments of the Kingdom of Lesotho and the Republic of South Africa. It comprises water transfer and hydropower generation components with associated ancillary developments. The water transfer component entails the construction of dams and tunnels in Lesotho, enhancing the use of water from the Senqu (Orange) River and its tributaries by storing, regulating, diverting and controlling the flow to affect the delivery of specified quantities of water to South Africa, and utilizing the delivery system to generate hydro-electric power in Lesotho.

The major works of Phase I included the construction of the Katse Dam, the transfer and delivery tunnels, ‘Muela Hydropower Plant and the Mohale Dam. The Phase II water transfer component comprises a dam at Polihali and a gravity tunnel that will connect the reservoir at Polihali with the Katse reservoir. The further feasibility studies for the hydropower component of Phase II have concluded that conventional hydropower is the more feasible option to meet Lesotho’s energy needs.

The Lesotho Highlands Development Authority (LHDA) is the implementing and management authority of the Lesotho Highlands Water Project, on behalf of the government of Lesotho.