The Lesotho Highlands Development Authority (LHDA) has appointed the Matla a Metsi joint venture to oversee the R445-million design and construction supervision of the Polihali dam.

The dam is one of the two main water transfer components of Phase 2 of the Lesotho Highlands Water Project (LHWP), with work expected to start this month.

The JV comprises South African construction companies GIBB and Mott MacDonald Africa, Tractebel Engineering and Coyne et Bellier of France, and Lyma Consulting Engineers of Lesotho.

The scope of services includes reviewing the geotechnical and other project information, the engineering design of the Polihali dam and appurtenant structures, the procurement of construction contracts and supervising the construction on behalf of the client.

Skills development and technology transfer to Lesotho and South African nationals and the training of LHDA staff for the purposes of operating the dam are also components of the consultancy contract.

The Polihali dam comprises a 164-m-high concrete faced rock fill dam (CFRD) on the Senqu river, a 50-m-high CFRD saddle dam, a concrete side-channel spillway, a free-standing compensation outlet tower and appurtenant works.

The design period will take around 18 months and will be followed by the procurement of the construction contractor.

Construction on the dam is expected to start in December 2019 or January 2020, with the dam envisaged to be completed in the wet season of 2023.

Phase 2 of the LHWP builds on the successful completion of Phase 1 in 2003. It delivers water to the Gauteng region, using the water delivery system to generate hydroelectricity for Lesotho.

Phase II will incrementally increase the current supply rate of 780-million cubic metres a year to more than 1.27-billion cubic metres a year.

Simultaneously, it will increase the quantity of electricity generated in Lesotho and is a further step in the process of securing an independent electricity source to meet Lesotho’s domestic requirements.