Lesotho Highlands Water Project Phase II to boost water supply to South Africa

23 Jan 2023 by The Water Diplomat

Katse Dam in Lesotho

With the awarding of major contracts, Lesotho and South Africa are satisfied that phase II of the Lesotho Highlands Water Project (LHWP) is now underway. The LHWP is a multi-phase international project between Lesotho and South Africa established through a treaty signed by the two countries in 1986. Phase I involved the construction of a 185-metre-high dam and augmenting South Africa’s freshwater supply by transferring water from the Maluti mountains into the Vaal River system through a 48 km long tunnel and a tail pond. Already augmented by water supply from from Mohale dam, completed in 2002, contracts have now been awarded for the construction of the Polahali Dam and the Polahali Transfer Tunnel, which suignal the commencement of phase II of the project.

The Polahali dam is to be constructed at the confluence of the Senqu and Khubelu rivers. The dam is designed as an additional supply dam which will augment the supply of the existing Katse dam, also in Lesotho and part of the LHWP phase I. Through the Kaste dam , which has enabled the transfer of almost 18 billion cubic metres of water to South Africa since 2004.  Through phase II of the LHWP, the annual supply capacity will increase from the current 780 million mᶟ to 1.2 billion mᶟ. A 38 km transfer tunnel will enable water transfer through gravity flow to Katse Dam. Additionally, phase II will enable the addition of 80 MW of electrical power to the existing 72 MW produced at the Muela hydropower plant.   

Additionally, a Lesotho-Botswana Water Transfer Scheme is envisaged by the Orange-Senqu River Commission (ORASECOM) on behalf of The Republic of Botswana, the Kingdom of Lesotho, The Republic of Namibia and the Republic of South Africa for Lesotho’s lowlands. This would involve the construction of a dam on the Makhaleng River and a 712 km bulk water conveyance system.