The City of Cape Town is investing in groundwater schemes to secure its water supply for the future. Three new aquifers will add 105 million litres of water per day by 2036.
Investing in aquifers is one of the Water and Sanitation Directorate’s strategic interventions, towards introducing new water sources for the future.
To prepare for a growing population while navigating the unpredictability of climate change, the city is gaining momentum in adding three groundwater schemes as part of the roll out of the New Water Programme.
Groundwater abstraction is the removal of water from aquifers. It involves drilling a hole deep into the ground, followed by fitting a pump into the borehole and pumping up water from the ground.
The water is then filtered and treated to national water standards. Tapping into groundwater provides an additional source of water to stave off reliance on rain-fed dams.
During the previous financial year, the city invested R390 million in its groundwater schemes.
A further R445 million has been set aside in the current 2024/25 financial year, towards adding 105 million litres of groundwater to the city's drinking water supply per day, by 2036.
This groundwater supply target from aquifers was set as part of the Water Strategy, to fulfil the city's commitment to diversifying available water resources for improved water security.
Continuous developments are under way to commission three groundwater schemes: Table Mountain Group Aquifer, Cape Flats Aquifer and Atlantis Aquifer.
Steady progress has been made in the past year in the following areas:
Table Mountain Group Aquifer (TMG)
Table Mountain Group Aquifer is the biggest of the three aquifers comprising approximately 11 000 km².
There are currently eight production boreholes, which have pumped into Upper Steenbras Dam since August 2020.
They yield approximately 20 million litres of water per day.
"We are developing the Peninsula Aquifer, which will increase the wellfield yield to approximately 25 million litres of water per day," the city said.
This amount can provide 50 000 households (four people per household) with 125 litres of water per person, per day. "We aim to produce 50 million litres of groundwater per day from the various planned TMG wellfields."
A further three drilled boreholes will be equipped giving a production fleet of 11 boreholes.
A new water use licence for the Steenbras wellfield was issued by the National Department of Water and Sanitation (DWS), superseding the previous authorisation.
Preparations are being made for trial operations of a new production borehole, which has been fully equipped.
Electrical and mechanical equipment is being installed for an additional four boreholes, with completion expected by the end of August 2024.
Drilling of two, deep core boreholes in the Steenbras area has started and is scheduled to be completed by December 2024.
Current exploration efforts include drilling two additional core boreholes in the Groenlandberg area, which has the potential to become a future wellfield.
Cape Flats Aquifer (CFA)
The Cape Flats Aquifer stretches over 400 km², from False Bay in the south, to Brackenfell in the northeast and Milnerton in the northwest.
The Cape Flats Aquifer Management Scheme (CFAMS) consists of five groups of boreholes; Strandfontein West, Strandfontein North and East, Philippi, Hanover Park, Mitchells Plain.
As there are no dams in this area, water abstracted from the boreholes is piped directly to the closest water treatment plant.
"The boreholes are expected to produce 50 million litres a day starting in late 2022. In order to ensure the longevity of the aquifer, and to prevent over-abstraction, we plan to recharge the Cape Flats Aquifer through a process called managed aquifer recharge."
The 'six million litre per day' Advanced Water Treatment Plant (AWTP) in Strandfontein West is in the commissioning phase, with performance testing nearing completion.
Drilling for the final two production boreholes at Strandfontein West will be done after land transactions have been concluded, followed by equipment installation and commissioning.
Construction of the '10 million litres per day' Philippi Water Treatment Plant started in June 2024, with borehole drilling and pipeline construction under way.
A series of injection boreholes for aquifer storage and recovery are in progress.
The civil works on the CFA Managed Aquifer Recharge (MAR) advanced treatment plant are nearing completion, with major building roofs installed. Site work, such as services and roads, are expected to be finalised by September 2024, with electrical-mechanical components simultaneously starting in August 2024.
Atlantis Aquifer
The Atlantis Aquifer covers an area of approximately 250 km² along the West Coast.
The Atlantis Water Resource Management Scheme has supplied Atlantis with groundwater from the sandy Atlantis Aquifer since the 1970s.
Water is pumped from two groups of boreholes, namely Witzands and Silwerstroom wellfields.
The scheme also comprises wellfield and coastal recharge basins, which replenish the groundwater with treated domestic wastewater and stormwater, to maintain groundwater supplies and ensure environmental sustainability.
The AWRMS supplies between five million to nine million litres of drinkable groundwater per day, and around 0,5 of the city's supply comes from the Atlantis Aquifer.
Ongoing refurbishment, as well as optimisation of the wellfields and managed aquifer recharge (MAR) infrastructure is expected to increase the groundwater supply volume to 25 million litres per day.
A total of 25 boreholes in the Witzands wellfield are being equipped with the required infrastructure to integrate it into the water system and 17 of these have been commissioned and are ready for trials. The remaining eight boreholes are set to be commissioned by December 2024.
Drilling of additional boreholes in the Silwerstroom wellfield was completed in June 2024.
Construction of a 2 x 5 million litres groundwater storage reservoir at the Witzands softening plant is under way.
Improvements to aquifer recharge basins are being made to enhance recharge water quality and maximise scheme yield.
"In the face of climate change and exponential population growth, Cape Town cannot afford to remain solely dependent on dams for water supply in the long-term.
"Having multiple sources of water contributing to the city's supply, positions us to be more resilient and enables us to meet growing demand for water security in the future," said the city's Mayoral Committee Member for Water and Sanitation, Councillor Zahid Badroodien.
City of Cape Town New Water Programme (Aquifers)
Description | Water Strategy | Planned completion date | Anticipated yield(Ml/d) |
Table Mountain Steenbras P1 | 2020 | Jun 2023 | 25 |
Table Mountain Nuweberg P2 | 2022 | Jun 2040 | 15 |
Table Mountain Groenlandberg P3 | 2022 | Jun 2040 | 12 |
CFA Strandfontein West | 2020 | Jun 2024 | 6 |
CFA Hanover Park | 2021 | Jun 2026 | 4.8 |
CFA Strandfontein N & E | 2021 | Jun 2030 | 18 |
CFA Philippi | 2021 | Dec 2027 | 7.2 |
CFA Mitchells Plain WTP | 2021 | Jun 2030 | 24 |
Atlantis Aquifer | 2021 | Jun 2026 | 16 |
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