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

5th June 2015

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 to 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 dam. The tunnel is sized to convey a peak power generation flow of 35 m3/s. 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, three kilometres 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 and 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 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. A primary school will be built.

The existing camp for construction workers at Mphorosane will be refurbished for use by the Polihali-to-Katse tunnel contractors. Improvements and expansions to the existing water and sewage treatment plants will be required. Other ancillary services will be constructed as determined during the design phase.  A satellite police station and accommodation facilities will be built and manned by Lesotho.

The upgrading of the existing hospital facilities at the Mamahau mission will be investigated and implemented to serve as a jointly managed project hospital, if deemed feasible.

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; socioeconomic and public health studies. The programme also includes environmental- and social-impact assessments, and the implementation of the subsequent environmental and social management and action plans.

Social development programmes
Social development 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. Their implementation will soon be agreed to by the parties to impose the absolute minimum disruption to the affected households and communities.

These 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.

Pumped-storage scheme
Phase II might also include a pumped-storage scheme and associated transmission lines and works using the existing Katse reservoir as the lower reservoir and a new upper reservoir in the Kobong Valley. The implementation of the scheme is subject to a joint decision by the two governments, which is still being debated.

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

Duration
Phase 2 of the LHWP is expected to start supplying South Africa with water by 2023.

Latest Developments
The LHDA has appointed three consultants for work packages as part of Phase 2 of the LHWP.

The contracts, worth a collective M40-million, have been awarded to the SMEC-FMA joint venture (JV); Jeffares & Green, in association with GWC Consulting Engineers; and the Maseru-based Maleka, Ntshihlele, Putsoa JV.

The contracts include the design and supervision of the construction of the Polihali North East access road; the supervision of geotechnical investigations for the Polihali dam and the Polihali–Katse water-transfer tunnel; and the demarcation of the Polihali reservoir.

The Polihali North East access road contract, overseen by the SMEC JV will entail the upgrade of the existing road for the safe movement of construction vehicles during the mobilisation of machinery and facilities for other advanced infrastructure contractors.

The Jeffares & Green JV will undertake the supervision of the geotechnical investigations for the Polihali dam and the Polihali–Katse water transfer tunnel. This wil involve extraction of rock and soil for testing to provide comprehensive data for the dam and tunnel design consultants.

The Polihali Reservoir contract, awarded to the Maleka, Ntshihlele, Putsoa JV, entails surveying and building beacons around the perimeter of the Polihali reservoir at a level 5 m higher than the full supply level.

Reservoir demarcation is critical for the acquisition of land and the resettlement and compensation of people in the district, whose homes and livelihoods will be affected by the construction of the dam.

The implementation of environmental and social mitigation measures will also start shortly, in ahead of the main access roads, and the dam and tunnel contracts.

On Budget and on Time?
Too early to state.

Key Contracts and Suppliers
C4/Seed joint venture (feasibility study); the TCTA (debt management and funding of the water-transfer portion of the project, as well as the operation and maintenance of the delivery tunnel north); Mops Civil (access road) and Aecon (construction of measuring weir).

Contact Details for Project Information
LHDA public relations manager Masilo Phakoe, tel +266 2224 6000 or email  phakoem@lhda.org.ls.

Edited by Martin Zhuwakinyu
Creamer Media Senior Deputy Editor

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