Table Mountain Group Aquifer
Providing a sustainable water supply in the Western Cape
“Cape Town is experiencing a severe drought. The engineering strategy, coupled with digital innovations that were developed for the Table Mountain Group Aquifer project, intend to help ensure that residents of the Western Cape have an adequate, sustainable water supply well into the future,” says Stephan Kleynhans, Zutari Civil Engineer.
The City of Cape Town started developing a series of wellfields to abstract groundwater from the Table Mountain Group (TMG) aquifer, a potentially high yielding regional aquifer. The project forms part of the city’s water strategy to provide a more diversified and resilient water supply in response to the severe drought that occurred in the Western Cape in 2017.
The TMG aquifer is a major aquifer system that can provide large bulk water supply for local municipalities and irrigation water for agriculture in the Western and Eastern Cape Provinces.
In 2002, Zutari was appointed for the project management and conceptual infrastructure planning for the exploratory phase of the feasibility study and pilot project. The five-year exploratory phase of the project determined that the aquifer held tremendous potential, but needed to be studied. For the second phase of the project, Zutari was appointed as the consultant for the TMG aquifer, which included project management, infrastructure planning, an environmental impact assessment (EIA), and the design of the aquifer.
Zutari has undertaken the feasibility, conceptual and detailed design and site supervision for the wellfield development. The first wellfield developed is located within the catchment of the Steenbras Dam and is estimated to yield up to 30 Ml/d of water. The Steenbras wellfield will be extended northwards towards Nuweberg, adding up to 15 Ml/d of water. Other wellfields are being investigated in the Theewaterskloof (Groenlandberg), Wemmershoek and Voëlvlei areas.
The Steenbras wellfield is located within the Steenbras Nature Reserve, which is an environmentally sensitive area. As a response to provincial and national disaster declarations issued during the 2017 drought, a Section 30(A) directive was issued to the city in terms of the National Environmental Management Act, Act No. 107 of 1998 (NEMA).
“Cape Town is experiencing a severe drought. The engineering strategy, coupled with digital innovations that were developed for the Table Mountain Group Aquifer project, intend to help ensure that residents of the Western Cape have an adequate, sustainable water supply well into the future”
We foresee that the first phase of the Table Mountain Group aquifer project will make approximately 10 Ml/d of water available for use.
This waived the need for an EIA process, subject to strict environmental conditions. Implementing the wellfield under the Section 30(A) directive, with Day Zero looming, was uncharted territory and required an innovative, proactive approach from all stakeholders.
Zutari established an environmental focus group to involve interested and affected parties as well as appointed environmental specialists to provide input on botany, freshwater ecology, search and rescue, offsets, visual impact and groundwater. Zutari, in conjunction with the governmental organisation responsible for maintaining wilderness areas and public nature reserves in the Western Cape, Cape Nature, joined forces to create a new specialist screening tool that enables the project team to screen boreholes from their computers. Before the development of the tool, the team would have to physically research each area to determine whether borehole drilling would be environmentally acceptable. The tool creates multiple layers of GOS data from various environmental sources to obtain information on where the boundaries of world heritage site developments are, which types of botanical species exist on the potential site, and other critical environmental information that is needed to determine the potential risk of impact.
“We foresee that the first phase of the Table Mountain Group aquifer project will make approximately 10 Ml/d of water available for use. The digital innovations that are used are helping us to prevent over-abstraction and environmental damage, and the result will assist the City of Cape Town in making additional water supply available in the region,” says Stephan Kleynhans.
*The Aurecon Africa business has been officially renamed Zutari as at 21 July 2020. Zutari acquired Aurecon Middle East on 20 November 2020.