The Lesotho Highlands Water Project

Mutually Beneficial Regional Integration and Cooperation - An African Success Story

By Shumirai Chimombe

Lesotho Highlands Water Project (LHWP) At A Glance

Harnesses the water resources of the Lesotho highlands through the construction of a series of dams and tunnels for the mutual benefit of Lesotho and South Africa, supplying water to the Gauteng region of South Africa and hydropower to Lesotho.

Phase 1A - Katse Dam

Comprises 185m high Katse Dam (a double curvature concrete arch dam on the Maliba-mats’o River and second largest dam in Africa), Muela hydropower station, Muela Dam, the transfer tunnel and delivery tunnels (South and North) .

The hydropower plant at Muela, situated mid-way between the Katse Dam in Lesotho and the Ash river outfall in South Africa now enables Lesotho to generate its own electricity needs.

Phase 1B - Mohale Dam

Comprises 145m high Mohale Dam - the highest concrete-faced rock fill dam in Africa located at the confluence of the Senqunyane and Likalaneng Rivers. Built as a backup reserve to the Katse Dam, the two dams are connected by a tunnel that ensures there’s enough water to meet South Africa’s everincreasing demand.

The Matsoku Weir and Tunnel comprises a 19m high, 180m long mass concrete structure together with the adjoining electro-mechanical equipment on the Matsoku river. This weir will divert flood waters through a tunnel into the Katse reservoir at Kutu-Kutu.

Phase 2 - Launched in 2023 and Estimated Completion In 2028

Molihali Dam and appurtenant works

Like the majestic Mohale Dam, both the Polihali Dam (166m) and the saddle dam (43m) in height will be concrete faced rockfill dams.

Polihali transfer tunnel

Just as water from Phase I’s Mohale reservoir flows through the interconnecting Mohale Tunnel to the reservoir at Katse, so will water from the Polihali reservoir flow by gravity through the Polihali transfer tunnel on its way to Katse.

Hydropower

Article 8 of the Phase II Agreement determined that the hydropower generation component would comprise a pumped storage scheme utilising the existing Katse reservoir as the lower reservoir and a new upper reservoir in the Kobong valley, or any other scheme to generate hydropower. It is expected that the Oxbow Hydropower Scheme which will be constructed in Botha Bothe will increase Lesotho’s renewable energy. The environmental and social impact assessment (ESIA) as well as the design and construction supervision contracts were already awarded in 2024.

Source: Lesotho Highlands Development Authority

The Lesotho Highlands Water Project (LHWP) is a multi-phased, multi-billion Maloti/Rand binational partnership between the governments of the Kingdom of Lesotho and the Republic of South Africa. The project is based on a treaty agreed upon in 1986 and the ensuing 2011 Agreement signed between the two governments to supply water to the Integrated Vaal River System (IVRS) which ensures water security for Gauteng, the Free State, the Northern Cape and the North West. The project harnesses the water resources of the Lesotho highlands through the construction of a series of dams and tunnels for the mutual benefit of Lesotho and South Africa, supplying water to the Gauteng region of South Africa and generating hydropower for Lesotho.

The project is implemented by the Lesotho Highlands Development Authority (LHDA), which is a public entity of the government of Lesotho, and the Trans-Caledon Tunnel Authority (TCTA), a South African state-owned agency of the National Department of Water and Sanitation (DWS),charged with financing and implementing bulk raw water infrastructure projects. Phase One, consisting of the Katse Dam, Muela power station, Mohale Dam and 82km of tunnels, was completed in 2003 and transfers 780 million cubic metres of water per annum into the IVRS comprising of 14 dams that provide water to the Gauteng province and to key industries within the province.

The Katse Dam, described as “a striking piece of modern engineering”, is one of less than 30 double curvature concrete arch dams in the world; one of the world’s 10 largest concrete arch dams in terms of its volume; and the second highest dam in Africa. The dam has since its construction in 1991 been attracting thousands and thousands of visitors and tourists who come to see this engineering marvel, according to the LHDA.

Boosting Water Supply to South Africa and Stimulating Lesotho’s Economic Growth

In May 2023 President Cyril Ramaphosa, His Majesty King Letsie III, and Lesotho’s Prime Minister, Samuel Ntsokoane Matekane, launched Phase 2 of the Lesotho Highlands Water Project.

In a statement, the South African Presidency indicated that the launch was a critical step on the journey to greater water and energy security for South Africans and Basotho, and is a demonstration of the strong relations between the two countries. “It is also a demonstration of the human capital and technology that is shared and deployed jointly as neighbours, in the interest of improving the lives of citizens and economic development in both nations. South Africa and the Kingdom of Lesotho share a close historic relationship whose substance today entails strengthened economic cooperation between our two countries.”

The project will cost approximately R43 billion and is scheduled to be completed in 2028. Once completed it will transfer an additional 490 million cubic metres of water per annum from the Orange (Senqu) River in Lesotho into the IVRS. The work involves the construction of a 165m high concrete-faced rockfill dam at Polihali and a 38km concrete-lined gravity tunnel connecting the Polihali Dam reservoir to the Katse Dam.

“This is not just a water transfer tunnel, it will serve as an umbilical cord that connects our two countries.” - Her Excellency Constance Seoposengwe, South African High Commissioner to Lesotho. Phase 2 will also see other parallel civil works such as the construction of roads and housing, the expansion of power lines and telecommunications, as well as environmental and social mitigating measures taking place.

Director: Cluster Communications in the SA Government Communication and Information system (GCIS), Josias Pila wrote: “This partnership between the countries dates back many years and will benefit both countries. Lesotho will benefit by collecting royalties [from South Africa] and jobs have also been created for local people in Lesotho. The Lesotho Highlands Phase 2 project is the biggest water infrastructure investment outside our borders in which South Africa is involved. It also forms part of government programmes aimed at sustainable water development and ensuring that everyone has access to water as enshrined in the Constitution.” The LHDA said that the Lesotho Highlands Water Project remains a one-of-its-kind cornerstone and benchmark for larger-scale engineering and construction on the African continent and beyond.

More importantly it contributes immensely to broad-based economic development across multiple pillars, including infrastructure development, business opportunity, job creation, environmental protection and many more livelihoods elevation programmes.

“Through the advancement of this water resource, the LHWA must stand as a shining example of regional integration demonstrating how collaborative efforts can lead to harmonious co-existing and mutual benefit.”