Lesotho Highlands Water Project

Katse Dam reservoir and intake tower

A 320 m long WIRTH 529 tunnel boring machine used on the project

Lesotho Highlands Water Project

The Lesotho Highlands Water Project (LHWP) is an ongoing water supply project with a hydropower component, developed in partnership between the governments of Lesotho and South Africa. It comprises a system of several large dams and tunnels throughout Lesotho and South Africa. In Lesotho, it involves the rivers Malibamatso, Matsoku, Senqunyane and Senqu. In South Africa, it involves the Vaal River. It is Africa's largest water transfer scheme.

The purpose of the project is to provide Lesotho with a source of income in exchange for the provision of water to the central Gauteng province where the majority of industrial and mining activity occurs in South Africa, as well as to generate hydroelectric power for Lesotho (currently almost 100% of Lesotho's requirements).

History

Efforts to create a dam in the location were spearheaded by then British High Commissioner Sir Evelyn Baring in the 1950s. After a complete feasibility study was conducted between August 1983 and August 1986 (German-British Lahmeyer MacDonald Consortium was appointed for this task), the project eventually began to realize.

The project has also been alleged to have had negative social and environmental effects. While compensation was provided in kind and paid to the few hundred households affected by the dams, there is criticism that it was insufficient. It was not intended to address the water supply problems in Lesotho, but by paying royalties to the Lesotho Government for development purposes benefits have reached much of the population.

In recent years, water from the scheme has been discharged into the Mohokare (Caledon) river to provide water to Maseru in times of critical shortages. The new dams have filled as anticipated and discharge of water from the dams into the downstream rivers continues in a scheme devised to preserve ecological balances. This discharged water flows to the Senqu (Orange) and while preserving the ecological status quo benefits only those communities along the rivers.

The project has had an important impact on Lesotho's infrastructure, as hundreds of kilometers of engineered paved roads were built in order to improve access to the different construction sites, and, together with engineered unpaved 'feeder' roads around the dams, continue to provide much improved communication for many villages in the mountainous interior.

Since its inception the project has been dogged by corruption which has resulted in a number of court cases involving both individuals and multinational corporations.

Project features

Below is an overview of the main features of the first three phases of the project.

	Phase IA	Phase IB	Phase II	Phase III
Name	Katse Dam	Mohale Dam	Polihali Dam	Tsoelike Dam
Dam height (m)	185	145	163.5	155
Power generation* (MW) (installed capacity)	110	N/A	N/A	N/A
Water transfer capacity* (m³/s)	16.9	10.1	28.0	8.6
Transfer tunnels	Yes	Yes	Yes	No
Completed	Yes	Yes	Under Construction	No (On hold)

* The values are estimates based on the feasibility study, and may differ from the current or eventual values, respectively.

Phase I

Phase IA: Katse Dam

This phase of the project was completed in 1998. It consisted mainly of the construction of the Katse Dam on the Malibamat'so River in Lesotho. A 45 Kilometre transfer tunnel was built from the Katse Dam to the Muela Reservoir. The Muela Reservoir is considered to be the tailpond, which supplies hydro-electric power for Lesotho. Stemming from the Muela Reservoir is a 37 Kilometre transfer tunnel to the Vaal Dam. Although the Katse Dam has power generation capability for local use, the primary purpose is as the storage reservoir for Phase IA, and to provide discharge into the transfer tunnel.

Phase IB: Mohale Dam

Mohale Dam and reservoir

This phase of the project was completed in 2002. It consisted mainly of the construction of:

• The Mohale Dam, a very large rockfill dam, located on the Senqunyane River.
• A 32 kilometer transfer tunnel between the Mohale Dam and the Katse Dam.
• Construction of the Matsoku Diversion Weir
• A 5.7 kilometer tunnel from the Matsoku Diversion Weir to the Katse Dam

The system is interconnected in such a way that water may be transferred in either direction for storage in Mohale or ultimate transfer to South Africa through the Katse reservoir.

Phase II

• In 2005, an agreement between the Governments of South Africa and Lesotho was signed to proceed with feasibility studies.
• In 2006, the feasibility study was commenced and completed in late 2008.
• The agreement to implement Phase II was signed in Maseru on 11 August 2011.
• The launch of Phase II construction took place at Tlokoeng on 27 March 2014

Later phases

As initially conceived, three further dams were proposed further downstream after the Malibamatso joins the Senqu river, at Mashai, Tsoelike, and Ntoahae.

In 2007, further studies resulted in a modification, proposing instead a dam on the Senqu upstream from the confluence with the Malibamatso. This is currently the preferred extension of the scheme, although construction has not yet begun (as of December 2007).

See also

• Lesotho Highlands

External links

• Lesotho Highlands Development Authority
• Trans Caledon Tunnel Authority
• Lesotho Highlands Further Phases Feasibility Study