Construction | Powering tomorrow


IWP&DC provides information on a selection of hydropower and dam projects currently underway across the globe, updating on construction over the last 12 months


Above: Asphalt paving of the northern access road as part of the construction work for Lesotho Highlands Water project (LHWP)


2023 WAS A BUSY year on Phase II of the Lesotho Highlands Water Project with the start of the water transfer main works and final steps on advance infrastructure, bringing the promise of increased water supply to South Africa one step closer. The first signs of site establishment activity at the Polihali dam and transfer tunnel sites early in the year, following the awarding of the construction tenders at the end of 2022, were a welcome sight and confirmation that the Phase II water transfer main works had moved into the final and most critical construction stage. Simultaneously, procurement for the hydropower component is underway while several advance infrastructure construction programmes like bulk power and telecommunications infrastructure, housing, diversion tunnels, roads, Katse Lodge upgrade, operations centre and commercial centre have been completed or are nearing completion. This was reaffirmed in May at the formal sod turning


Below: Construction of the Senqu bridge as part of the LHWP commenced in late 2022 and is expected to be completed in 2026


ceremony at Malingoaneng, Mokhotlong for the water transfer main works and the Senqu Bridge. Officiated by His Majesty King Letsie III and the President of South Africa, His Excellency Cyril Ramaphosa, and attended by cabinet ministers and senior officials from both countries, it demonstrated the warm relations between the two countries and their commitment to a project that delivers much needed water to the Gauteng region and simultaneously provides hydropower to Lesotho and is considered to be one of the most successful cross-border water collaboration schemes between two sovereign states in the world. Early milestones in the dam and tunnel construction include the diversion of the Senqu River by the pre-cofferdam, and the subsequent diversion of the


river into and through the diversion tunnels ahead of the construction of the cofferdam upstream of the Polihali Dam wall in early August. Both the upstream and downstream cofferdams are expected to be completed by January 2024. Diverting the river through the transfer tunnels which


were constructed as part of the advance infrastructure creates a dry working area for the construction of the Polihali Dam. Excavations of the main dam and intake structure have commenced. A transfer tunnel milestone was the first blast making way for excavation works at the tunnel boring machine access adit in September 2023. The Polihali reservoir will inundate a large area which includes existing roads and bridges. Three major bridges are being built along the Maseru to Mokhotlong A1 road at the Mabunyane, Khubelu and Senqu rivers. Construction of the Senqu bridge commenced in


late 2022 and is expected to be completed in 2026. Construction of the other two bridges commenced in August 2023 following the construction tender award to the Concor-Nthane Brothers M&K Bridges Joint Venture. The three major bridges will provide access to Mokhotlong town across the reservoir even at full supply and retain connectivity to the national road network along the A1, the main road between the Mokhotlong district in the mountainous north-east of the country and Maseru. The major bridges programme is complemented by the construction of four pedestrian bridges and six vehicle bridges under the feeder roads and bridges programme to maintain access and ensure mobility for communities across and around the reservoir area.


10 | January 2024 | www.waterpowermagazine.com


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