Augmenting Water Supply

The Stellenbosch Town Council, at its January 2023 meeting, authorised the municipal manager to enter into an agreement with the Department of Water and Sanitation to take up the municipality’s allocation in terms of the Bergriver-Voëlvlei Augmentation Scheme (BRVAS). Once completed this scheme will supply the municipality with an extra 1.640 million m³/annum water through the Theewaterskloof Dam at a favourable rate.

Stellenbosch Municipality receives water allocations from several sources. The allocations from the Theewaterskloof Dam (3.000 million m³/a) and from the Eerste River (7.224 million m³/a) are fed by gravity and treated by the Paradyskloof Water Treatment Plant (WTP) and the Idas Valley WTP, respectively.

The allocation from the City of Cape Town (CoCT) is 6.848 million m³/a and comes into the system from the Wemmershoek Line, Faure Water Treatment Plant and the Blackheath Water Treatment Plant. Water from CoCT mainly supplies the areas outside Stellenbosch town, such as Raithby, Jamestown, Klapmuts, Pniel and Franschhoek.

Parts of Franschhoek also receive water from the Mont Rochelle Nature Reserve.

The water supply to the municipal area can further be augmented with water from various borehole fields created during the last drought cycle. These fields in the Stellenbosch, Klapmuts and Dwarsriver areas can provide 2.041 million m³/a.

Stellenbosch Municipality’s allowance in terms of the BRVAS is 1.640 million m³/a through the Theewaterskloof Dam. The attraction of this scheme is that in the long term it will make Stellenbosch less dependent on water from the CoCT and do so at a lower cost than will be due to CoCT.

The BRVAS entails the construction of a low-level weir and pump station downstream of Zonkwas Drift on the Berg River and a 6,3km pipeline to deliver the water to the Voëlvlei Dam. During winter approximately 23 million m³/a will be abstracted to the Voëlvlei Dam, once the ecological water requirements of the river and the estuary have been met. Stellenbosch Municipality’s contribution to the capital cost of the project will be paid through a higher price for its allocated water for the first 20 years, after that the price drops dramatically. Even including the initial capital component, it is still cheaper than buying treated water from the CoCT. The municipality has recently warned that dam levels in the Western Cape are 25% lower than they were at the same time last year and that consumers should use water sparingly. Of further concern is that forecasts suggest the return of the El Nino weather phenomenon in 2023 which leads to lower winter rains in the Western Cape.

Text: Editorial Desk | Image: Wikimedia Commons