Project Overview

A TUNNELLIN EXPERIENCE IN THE HEART OF THE KINGDOM OF LESOTHO.

Excavation of the tunneling required on Phase IA of the Lesotho Highlands Water Project (LHWP) has been an enormous undertaking. Hereunder is a study of the vital statistics that illustrates the scope of the achievements.

The bi-national, Lesotho Highlands Water Project (LHWP), between the Kingdom of Lesotho (KOL) and the Republic of South Africa (RSA), is one of the most comprehensive engineering projects of its kind in the world, aimed at harnessing the water resources of the highlands of Lesotho to the mutual advantage of South Africa and Lesotho. The whole concept of the LHWP can be traced as far back as around the 1930s§, in which the idea of capturing the Lesotho high summer rainfalls by dams and transferring to parts of RSA, enthused South Africa.

Preliminary Studies

The initial survey of the water potential of Lesotho was first introduced by the then British High Commissioner to Lesotho Sir Evelyn Baring around the 1950s. Ninham Shand of South Africa was appointed as consulting engineer to study the potential of harnessing the water of the Maluti Mountains for economic benefit of the Basotho people.
A study of the Oxbow project was undertaken for the Government of Lesotho from 1967 to 1968 (Ninham Shand and Partners, 1968). That study envisaged storage reservoirs at Oxbow and Pelaneng on the Malibamats’o River with tunnels northward to convey water to South Africa. In 1971 the Government of Lesotho (GOL) commissioned a further study (Binnie & Partners, 1971) which concluded that a 94m high Pelaneng dam could be constructed to divert a continuous supply of 8m³/s to South Africa.
In 1974 the Republic of South Africa (RSA) appointed Henry Olivier and Associates to carry out studies in connection with water and power projects in the neighboring countries. In a report submitted to the RSA in 1977 (Henry Olivier and Associates, 1977), ten alternative layouts for diversion of water from Lesotho to the Vaal basin and for possible hydroelectric projects associated with such projects were described.

Joint Preliminary Feasibility Study

A joint preliminary feasibility study of the project with each government appointing its own consultants to assist in the study was carried out in 1978. A preliminary Feasibility report (Olivier, Binnie, 1979) concluded that a constant flow of some 35m³/s could be transferred to South Africa using a phased construction of five reservoirs at Oxbow, Pelaneng, Soai, Polihali and Taung on the Malibamats’o and Senqu (Orange) rivers and approximately 102km of tunnel to transfer water to South Africa. The generation of hydroelectric power in Lesotho was an integral part of the project proposal.