The South African Department of Water Affairs and Forestry (Dwaf) recently revealed that it would shelve the proposed R5-billion Thukela water project (TWP), as it was determined that new water to the Vaal river supply area would only be needed beyond 2020.
The water resource development project was to have been situated in KwazuluNatal, with a strategic intent to augment water supplies to the industrial heartland of South Africa, otherwise known as the Vaal river system (VRS).
The TWP, in the uThukela region of Kwazulu-Natal, was seen to have the potential to stimulate local and regional economic growth, and contribute significantly to government’s policy objectives, including security of water supply to the VRS; economic empowerment of previously disenfranchised people; poverty alleviation; and job creation.
While it was estimated that additional water would be required in 2005/6, the feasibility study for the project determined that the date could be pushed back to 2012—15, prompting a decision to proceed to the TWP decision support phase (DSP) at the end of the feasibility study.
However, during the early stages of the DSP, it was determined that augmenting water supply to the Vaal river supply area would only be required after 2020.
This prompted Dwaf to formally close the project for some time to come.
Meanwhile, the feasibility study indicated that the project is technically feasible, and environmentally and economically viable. It was also determined that the TWP stands as an attractive alternative to augment the water resources in the Vaal river system, following phase 1B of the Lesotho Highlands water project.
Investigations into augmenting water supplies to the VRS began in 1994, and involved evaluations of alternative interbasin transfers of water from four catchments to the VRS.
The Thukela catchment has a total area of approximately 29 000 km2 and an undeveloped (virgin condition) mean annual runoff (MAR) of 3 865 x 10(6) m3.
The MAR expressed as average unit runoff is about 133 mm, which is equivalent to 16% of the mean annual precipitation (MAP) of 840 mm. However, MAP varies from more than 1 500 mm in the Drakensberg to 500 mm and less in the dry central regions of the basin.
Although there are a few large dams and numerous smaller ones in the Thukela river system, they are mainly located in the upper reaches of the Thukela river itself and in some of its tributaries.
For the most part, the Thukela river remains comparatively unregulated.
Water resource developments within the catchment are generally small and relate primarily to the needs of individual towns. The largest components of existing water development infrastructure are those associated with four interbasin transfer schemes.
These include the Tugela-Vaal project through which water is transferred via the Drakensberg pumped-storage scheme to Sterkfontein dam in the Vaal river catchment; the Zaaihoek scheme through which water is transferred to Majuba power station and the Grootdraai dam in the Vaal river catchment; the Mooi-Mgeni scheme through which water will be transferred to Midmar dam in the Mgeni river; and the Thukela-Mhlatuze scheme through which water is transferred to Goedetrouw dam near Richards Bay.
The proposed TWP was to transfer some 15 m3/s of additional water through the existing Drakensberg pumped-storage scheme into Sterkfontein dam, from the proposed Jana dam in the Thukela river and Mielietuin dam in the Bushman ’s river.