Lesotho Highlands Water Project – Phase II, Lesotho and South Africa

7th January 2016

By: Sheila Barradas

Creamer Media Research Coordinator & Senior Deputy Editor

  

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Name and Location
Lesotho Highlands Water Project (LHWP) – Phase II, Lesotho and South Africa.

Client
The Lesotho Highlands Development Authority (LHDA) and the Trans-Caledon Tunnel Authority (TCTA) are the implementing authorities.

The Lesotho Highlands Water Commission has an oversight function, advises the two governments and monitors the activities of the LHDA and TCTA.

Project Description
Phase I of the LHWP was officially completed in 2004.

Phase II of the LHWP will be implemented in terms of two distinct components: a water delivery system to augment the delivery of water to South Africa and a hydropower generation system.

Polihali dam
The Polihali dam will be built downstream of the confluence of the Senqu and Khubelu rivers and will be a 163.5-m-high concrete-faced rockfill embankment dam wall.

The crest length will be 915 m, with a full supply level of 2 075 m above sea level. A 49.5-m-high saddle dam and a side channel spillway will also be built.

Polihali to Katse tunnel
The 38.2-km-long, 5-m-diameter Polihali-to-Katse dam tunnel will be constructed to transfer water from the Polihali reservoir to the Katse reservoir.

Water will be abstracted from the Polihali reservoir through two separate concrete bell-mouth intakes on the western side of the Polihali reservoir, in the Khubelu river, 3 km upstream of the confluence with the Senqu.

Water will be transferred through the lower and upper intake tunnels to the intake gate shaft. Both tunnels will be constructed using drill-and-blast methods and will be fully concrete-lined. Hydraulic control will be effected by the valves in the intake structures.
The Polihali intake gate shaft will be used only for maintenance and water-quality control functions.

Advance infrastructure
Where possible, the existing infrastructure constructed in Phase I will be used. This includes access roads, power supply, telecommunication systems and camps.

Significant additional works contracts will be awarded for the construction of all-weather access roads, a bulk power supply network, telecommunications systems and project housing, as well as labour camps, on both ends of the transfer tunnel.

A permanent housing development will be established near the Polihali dam and transfer tunnel, which will consist of project offices, and residential and community facilities.

This will require extensive infrastructure development before the mobilisation of contractors for the two main works contracts of the Polihali dam and transfer tunnel.

The Polihali intake site will use the infrastructure required to construct the Polihali dam and the transfer tunnel. This includes feeder roads and bridges around the reservoir to connect affected communities, power supply systems, construction camps and communications.

The facilities at Katse dam will be used for the Polihali-to-Katse tunnel construction. Existing facilities will be used to house consultants and construction management teams. Improvements to the water and sewage treatment plants, clinic and lodge will be undertaken.

Other infrastructure
In addition to the main access roads to service the construction phase, other access and feeder roads will be constructed around the reservoir to connect affected communities using pedestrian and light-vehicle bridges, while a pair of major road bridges will be built over the Polihali reservoir at Tlhakola, crossing the Khubelu river, and, near Mokhotlong, crossing the Senqu river.

Environmental measures
Environmental mitigation measures, including environmental flow matters and baseline studies, will be implemented.

The full extent is being studied in detail for implementation.

An environmental and social management programme is being implemented to address potential environmental and social impacts associated with Phase II activities.

The programme comprises baseline studies, including those pertaining to environmental flow requirements, biological and archaeological (including heritage) studies, as well as socioeconomic and public health studies.

The programme also includes environmental- and social-impact assessments (ESIAs), and the implementation of the subsequent environmental and social management and action plans.

Social development programmes
These programmes, mitigation measures, resettlement requirements and baseline studies, as well as public relations and awareness campaigns, will be implemented.

The full extent of these measures are being studied and discussed.

Infrastructure developments might include medical clinics, feeder roads and bridges around the reservoir to connect affected communities, and social development projects such as schools, churches and community halls.

The above will be informed by the outcome of the baseline studies, as well as the sustainable development programmes to be designed.

Pumped-storage scheme
Phase II might also include a pumped-storage scheme, associated transmission lines and works using the existing Katse reservoir as the lower reservoir, and a new upper reservoir in the Kobong Valley.

The exact form of the hydropower component is still to be agreed by the governments of South Africa and Lesotho. The decision will be informed by further feasibility studies, with a request for proposals (RFP) having been issued for the additional studies required.

Value
The project is expected to cost R17.5-billion at completion.

Duration
Water delivery is expected to begin in 2024, based on the current project programme.

Latest Developments
Engineering and environmental consulting firm Jeffares & Green’s (J&G’s) geotechnical division, in association with Lesotho-based consulting firm GWC Consulting Engineers, has been appointed to undertake the supervision of 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 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 implementing authorities, namely 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 to advance infrastructure works and the main works of the water transfer component of the project.

The format and location of the hydroelectricity component will be confirmed pending the outcome of further feasibility studies, notes J&G, adding that the volume of work in Lesotho resulted in an office being registered in Maseru.

J&G’s geotechnical investigations will involve rock and soil extraction for testing purposes to provide comprehensive data for the dam and tunnel design consultants. The investigations will also identify the suitability, quality and quantity of construction material found at all investigated quarries.

Key Contracts and Suppliers
Maleka, Ntshihlele, Putsoa JV (reservoir demarcation); Jeffares & Green, in association with GWC Consulting Engineers (geotechnical engineers); SMEC-FMA JV (Polihali north-east access road – consultant) and Polihali Infrastructure Consultants, a joint venture between Mott MacDonald PDNA and Khatleli Tomane Moteane (planning, design and construction supervision of the housing and associated infrastructure – Phase II).

On Budget and on Time?
Water delivery is expected to begin in 2024, based on the current project programme.

It is too early to comment on the hydropower component, as it is being subjected to feasibility studies and its exact form is still to be determined.

Contact Details for Project Information
LHDA responsible manager – divisional manager Phase II Tente Tente, tel +266 222 46000 or email tentet@lhda.org.ls.
LHDA public relations manager Masilo Phakoe, tel +266 2224 6000 or email phakoem@lhda.org.ls.

Edited by Creamer Media Reporter

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