President Cyril Ramaphosa officially opened the Senqu Bridge in Mokhotlong, Lesotho, on Wednesday, hailing it as a symbol of enduring partnership between South Africa and its mountain kingdom neighbour.

The 825m structure, which rises 90m above the Senqu River gorge at an elevation of more than 2 100m above sea level, is the longest bridge in Lesotho and the largest of three being built to span the Polihali Reservoir.

Ramaphosa joined King Letsie III and Prime Minister Samuel Matekane at the ribbon-cutting ceremony for the bridge, which was constructed at a cost of approximately R2.4 billion over a three-year period.

“Rising high above the river valley, located more than 2 500m above sea level, this bridge has been built to endure. It will serve many generations to come,” Ramaphosa said at the inauguration.

The structure forms a critical component of Phase II of the Lesotho Highlands Water Project, a binational infrastructure initiative established under the 1986 treaty between South Africa and Lesotho.

Construction began in June 2023 and the bridge opened to traffic at the end of March this year.

The Senqu Bridge replaces an existing structure that will be submerged once the Polihali Dam is filled. It ensures continued access along the national A1 road network between Mokhotlong and Maseru.

The project employed over 1 200 people at its peak, with an average workforce of 800 over three years. Most workers were Basotho, with significant participation from women and youth. Lesotho firms received 29.6% of project expenditure, whilst South African black-owned enterprises accounted for 16.6%.

The bridge is an extradosed structure, a hybrid between a cable-stayed and prestressed box girder bridge, the first of its type in Lesotho. It features 17 piers, with 15 to be submerged up to 85 metres deep when the Polihali Reservoir reaches full capacity. The tallest pier stands 87.8m high.

Construction required 150 000 cubic metres of excavated rock, 10 000 tonnes of steel and 40 000 cubic metres of concrete. The deck was built using an incremental launch method from both abutments in 50-metre sections.

The bridge was designed by Zutari, formerly known as Aurecon Lesotho, working with White Life Consultants of Lesotho and Leporogo Specialist Engineers of South Africa.

The Lesotho Highlands Water Project is one of the most ambitious and successful transboundary water projects in the world.

The president acknowledged the challenges faced during construction. “The project has experienced a number of challenges. However, the project team stayed focused. It has worked to ensure that no affected communities and no households are left worse off by this construction,” he said.

Phase II of the Lesotho Highlands Water Project will increase water transfer volumes from 780 million to 1.27 billion cubic metres per annum whilst boosting Lesotho’s hydropower output. The overall project cost is estimated at between R42 billion and R53 billion.

The Polihali Dam currently stands at 44% completion, whilst the 38 km transfer tunnel connecting Polihali and Katse reservoirs is 51% complete. Water impoundment is planned for November 2026, with full commissioning expected in 2028.

“The Lesotho Highlands Water Project is one of the most ambitious and successful transboundary water projects in the world. It is the largest investment South Africa has ever made outside its borders,” Ramaphosa said.

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The president announced that South Africa will provide R30 million in humanitarian assistance to Lesotho from the African Renaissance Fund to strengthen the kingdom’s national response to HIV and tuberculosis.

“South Africans and Basotho will forever be bound together, shaped by a common destiny, grounded in history, geography, language and culture,” he said.

Water and Sanitation Minister Pemmy Majodina, Deputy Minister David Mahlobo and Deputy International Relations and Cooperation Minister Alvin Botes accompanied Ramaphosa to the ceremony.

On 20 April, Majodina and Natural Resources Minister Mohlomi Moleko unveiled a tunnel boring machine that will be used to drill the tunnel between the Polihali and Katse reservoirs.

ALSO READ: South Africa and Lesotho to open R2.4 billion Senqu Bridge