Lesotho Highlands Water Project

The Lesotho Highlands Water Project’s (LHWP) assets, the LHDA jointly with the Trans Caledon Tunnel Authority (TCTA) have started routine inspection and maintenance works on the water transfer and delivery tunnels.   This is to ensure continued sustainable operations and service of the tunnels and all electro-mechanical components from the Katse Intake Tower, through Muela Power Station to the Ash River Outfall.

Neem kennis dat daar onderhoudswerk op die hele Lesotho Hooglandwaterskema projek gedoen gaan word gedurende September (wat reeds begin is) asook Oktober en November.   Dit geld ook aan die Suid-Afrikaanse kant.  Dit is uiters noodsaaklik dat onderhoud gedoen moet word, vir die voorsiening van water, sowel as elektrisiteit vir Lesotho se gebruik.   Eskom gaan Lesotho in hierdie tyd van elektrisiteit voorsien, met die hulp van Mosambiek en ook bestaande voorsiening.    Spaar water waar moontlik.

Agtergrond …


The Lesotho Highlands Water Project is an ongoing water supply project with a hydro-power component, developed in partnership between the governments of Lesotho and South Africa since 1980.


The concrete arch of the Katse dam, which is the highest double curvature, concrete arch, gravity dam in Africa at a 185 m height. The prefabricated ring segments of the Mohale tunnel, 31.6 km long, which links Mohale dam to the reservoir. It was designed to provide an outflow of water at the average rate of 9.5 m3/s.

This channel, 31.6 km long, is navigable and fully lined with a facing, half of which is underground and of a 4.66 m diameter, whilst the other half has a 4.25 m diameter.

The supply of the channel is located in the Mohale reservoir, two sections designed to be submerged. Two shafts, one at each extremity, allow the supply and discharge channels to be isolated from the main channel.

The latter is located underground. The weir is sealed by a metallic partition. A gravitational supply channel, 6.4 km long, takes water from the dam of the river Matsoku to the reservoir.

The main aim of the concrete realised is optimal water tightness.

Concrete formulation:
• Total volume of concrete: 2 600,000 m3 for the whole project, 200,000 m3 for the transfer tunnel.
• Specifications: Maximum water reduction associated with a workability suitable to place good concrete. Compressive strength: 3 MPa at 8 hours.Concrete to be pumped over a 200 m distance.

Project participants :

• Designer: Lesotho Highlands Consultants consortium.
• Owner: Lesotho Highlands Development Authority
• Contractor: Highlands Water Venture, Spie Batignolles, Campenon Bernard, Zublin, Balfaur Beatty & LTA
• Companies: Hochtief, Impregilo & Concor.



New water flow meters will be installed at Ngoajane flow measuring station and replace the valve at the ‘Muela Hydropower’ station bypass, while routine inspections and maintenance work will be carried out within the South African side.   All this maintenance need to be done to ensure that the Lesotho Highlands Water Project is able to deliver on its mandate of generating hydro-power in Lesotho and transferring high quality water to South Africa.    In order to ensure that inspection and maintenance workers can gain access to the tunnels, there would be a stoppage of water transfer to South Africa and electricity generation in Lesotho.    During this time, Lesotho will not be generating their own electricity, but will rely on supply from Eskom in South Africa and the EDM in Mozambique.  Hydro-power generation already stopped at 30 September 2019 and Katze repair work started on 19 September 2019.

Lesotho Highlands Water Project has started maintenance work


Lesotho’s Muela hydropower plant has been generating 72 mega watts of electricity daily since it was opened in 1999. It is part of the multi million rand Lesotho Highlands Water Project which transfers water to South Africa. Hydroelectric Power Generation


Lesotho will depend on imported electricity duirng routine maintenance within the whole Lesotho Highlands Water Project and specific the Muela Hydro power station.   South Africa is estimated to supply 30 percent of Lesotho’s power needs with Mozambique contributing 20 percent of the consumption.    The rest of the power comes from the ‘Muela Hydropower Station , which produces about 72 megawatts (MW).

A number of contracts for the work to be done and equipment to be replaced were awarded.   The maintenance workers have also been given training on safety in the tunnels, first aid and use of breathing apparatuses in cases where air within the tunnel is insufficient.   The change of power supplier would also not affect power charges.   H

Lesotho to rely on imported power


The Lesotho Highlands Development Authority (LHDA) in conjunction with the Trans-Caledon Tunnel Authority (TCTA) have successfully shut down the Lesotho Highlands Water Project (LHWP) water transfer and delivery tunnel and associated systems for maintenance work, South Africa’s department of water and sanitation said on 10 October.   The LHWP is an ongoing partnership between the governments of Lesotho and South Africa which comprises a system of several large dams and tunnels throughout Lesotho and delivers water to the Integrated Vaal River System (IVRS) in South Africa.

The water will be shutdown from 1 October to 30 November to allow them to perform inspections and maintenance work that would ensure that the conveyance system continued to operate optimally.    There would be no transfer of water into the integrated Vaal River System during this period.     The system — which consists of fourteen dams with catchments in the provinces of Mpumalanga, Free State, Northern Cape and North West — was at 74.8% of capacity.    The flow and use of water in the affected rivers/ dams will be monitored during the shutdown period.



The Lesotho Highlands Development Authority (LHDA) in conjunction with the Trans-Caledon Tunnel Authority have successfully shutdown the Lesotho Highlands Water Project (LHWP), water transfer and delivery tunnel and associated systems.    The two-month shutdown (01 October to 30 November 2019) is aimed at allowing the two entities to effectively perform inspection and maintenance work that will ensure that the conveyance system continues to operate optimally. Consequently, there will be no transfer of water into the Integrated Vaal River System in this period.



Various municipalities have urged their residents to use water sparingly after reservoir levels across the city dropped severely in the past days   Utility services MMC Abel Tau said Rand Water restricted had its water supply by 30 percent.   “The water demand is extremely high because of the high temperatures currently being experienced and the reservoirs cannot keep up,” he said.

Residents were reminded of the following hints provided in terms of the partial restrictions that the Tshwane metro announced in May last year:

* Water gardens before 06:00 or after 18:00 and only when necessary.

* Plant indigenous or drought-resistant shrubs in the garden.

* Use a broom instead of a hosepipe to clean driveways or patios.

* Use grey water to water gardens and flush toilets.

* Report water leaks and burst pipes.

* Install water-saving devices.

* Where possible, install a low-flow showerhead and tap aerators.

* Use a dual-flush toilet cistern.

* Collect rainwater to reuse in the garden or to wash the car.

* Cover the swimming pool to reduce evaporation.

* Take a quick shower rather than a bath.

* Close a running tap while brushing teeth or shaving.

* Regularly check toilets and taps for leaks.

“Residents are requested to remain vigilant in curbing wastage of this scarce resource and to make saving water a part of their lifestyles by following the above-mentioned tips,” the metro said.





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