Jeffares & Green’s (J&G’s) geotechnical division, in association with Lesotho-based consulting firm GWC Consulting Engineers,
has been appointed to supervise the geotechnical investigations for the Polihali dam and a 38.2-km transfer tunnel to the Katse dam, which form part of Phase 2 of the Lesotho Highlands Water Project (LHWP).
Construction of the dam and tunnel is expected to start towards the end of 2018, with water delivery and hydroelectricity generation expected to begin in 2024.
With Phase 2 still in the early stages, the 2015/16 focus of the Lesotho Highlands Development Authority and the Trans-Caledon Tunnel Authority will be on the procurement of consultants and contractors, such as J&G and GWC Consulting Engineers, for the advance infrastructure works and the main works of the water transfer component of the project.
Further feasibility studies will confirm the format and location of the hydroelectricity component of the project, notes J&G, adding that work volumes in Lesotho have necessitated it registering an office in Maseru.
The LHWP is a binational project by the governments of South Africa and Lesotho.
It is a multiphased project aimed at transferring up to 70 m3/s of water from the Senqu river, in Lesotho, to the Vaal river in Gauteng, while using the water delivery system to generate hydroelectric power for Lesotho.
The first phase, completed in 2004, comprised constructing two dams – Katse and Mohale – a hydropower station, an interconnecting tunnel between the dams and a delivery tunnel into South Africa.
Population increase in the Lesotho Lowlands, compounded by industrial development, has put pressure on the area’s limited groundwater and the available river-flow extractions.
J&G collaborated with UK-based consultants Parkman in 2002 to undertake a feasibility study on improving the area’s bulk potable supply system. Completed in 2004, the study recognised that, in addition to constructing the Metolong dam as part of the LHWP, river-extraction systems should also be established to serve the Lowlands areas. This led to the Lowlands Bulk Water Supply Scheme.
In 2009, the Metolong Programme Implementation Unit signed a contract with the Lesotho Waterworks Joint Venture (LWJV) to undertake the master planning, detailed design, tender documentation, procurement and construction supervision for Phase 2 of the advanced infrastructure programme to serve the Metolong dam, water treatment works and conveyance system works.
The LWJV comprised J&G, SSI Engineers & Environmental Consultants (DHV Netherlands), and GWC Consulting Engineers, of Lesotho.
