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Lesotho Highlands Water Project – Phase II

19th August 2016

By: Sheila Barradas

Creamer Media Research Coordinator & Senior Deputy Editor

  

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Name of the Project
Lesotho Highlands Water Project (LHWP) – Phase II.

Location
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 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 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 on 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.

Jobs to be Created
Not stated.

Value
As of November 2015, the estimated cost of the Phase II water transfer component was R22.9-billion at completion.

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

Latest Developments
Construction of the Polihali dam – an integral part of the LHWP Phase II – is expected to start in 2019.

The Polihali dam, the Polihali–Katse transfer tunnel and other infrastructural aspects of the LHWP Phase II should be completed by 2024. Once Phase II has been completed, the amount of water supplied to South Africa through the LHWP will progressively increase from 780-million cubic metres yearly to about 1.27-billion cubic metres yearly over the following 20 years.

LHWP implementing body LHDA CEO Refiloe Tlali says that, as construction of the dam is expected to begin in 2019, its impoundment should start in the second half of 2023. Water delivery will follow once the reservoir has filled sufficiently, which will take at least one or two rainy seasons.

The procurement process for the design and construction supervision of the Polihali dam and the Polihali transfer tunnel includes a prequalification process, which has been concluded. Tender documents to the four shortlisted bidders for the dam and the three for the tunnel will be issued by the end of August.

Construction of the dam and transfer tunnel will be preceded by the construction of advance infrastructure works, including roads, bridges, housing and telecommunications.

To date, five contracts have been awarded for various elements of the advance infrastructure works. Further, the awarding of a contract for the ESIA of the construction of Phase II is imminent.

Tlali notes that the advance infrastructure work contracts include Contract 3017 for the demarcation of the Polihali reservoir. This entailed the construction of more than 1 300 beacons to mark the 230 km perimeter of the reservoir. It was awarded in April last year to Lesotho-based consultancy the Maleka, Ntshihlele, Putsoa Joint Venture (JV).

Contract 3014 for the design and construction supervision of the Polihali north-east access road was also awarded in April last year. SMEC-FMA JV (comprising the Bloemfontein branch of international engineering consultancy SMEC and Lesotho-based civil engineering firm FM Associates) is still completing the designs. Tlali says construction of the access road is expected to begin next year.

Contract 3015 for the evaluation, optimisation and site supervision of geotechnical investigations was awarded to consultant Jeffares & Green (now called JG Afrika) and Lesotho-based GWC Consulting Engineers.

Contract 4016 for geotechnical investigations was awarded to geotechnical drilling company Diabor. Geotechnical work will, therefore, be conducted by Diabor, but be overseen and analysed by JG and GWC.

Tlali says the geotechnical investigations have been divided into stages. The first stage involves conducting seismic refraction surveys, core drilling and logging of the cores retrieved from the boreholes. It will also include the extraction and testing of rock samples, as well as sampling sand in the area to establish that the material at the quarry sites is suitable for use in the making of concrete. The first stage is under way, with results expected at the end of the year.

Contract 3009 for the planning, design and construction supervision of housing and associated infrastructure was awarded to Polihali Infrastructure Consultants – a JV comprising South Africa-based engineering consultancy Mott MacDonald and Lesotho-based Khatleli Tomane Moteane.

This contract, awarded in June last year, comprises accommodation facilities for the staff and workforce, site offices, workshops, plant yards and other work areas. “Work on the planning and design of this aspect of the advance infrastructure is well under way,” says Tlali.

Phase II also includes a hydropower aspect. The Phase II Agreement determined that a hydropower-generation component – to be used to supplement Lesotho’s power supply – will comprise the 1 200 MW Kobong pumped-storage scheme or any other similar scheme.

The scheme, consisting of a hydropower station between two reservoirs will, theoretically, use the existing Katse reservoir as the lower reservoir and a new upper reservoir in the Kobong valley or any other similar scheme subject to agreement on the outcome of a feasibility study to generate power.

Tlali says the LHDA is negotiating with one of the firms that submitted its bid to conduct the feasibility study. Negotiations should conclude in the third quarter of this year, with the study starting by the fourth quarter. The study is expected to take about two years to complete.

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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