/ 11 July 2024

Cape Town needs to spend well over R2 billion to achieve water security in the next decade

Cape Flats Aquifer Drilling
Aquifer drilling on the Cape Flats. Photo supplied by CoCT

The City of Cape Town needs to spend R2 billion on building and refurbishing water infrastructure, as well as spend on developing new water sources, to achieve water security for the next 10 years.

Any delays in implementing the water plan will increase the probability of water restrictions as it closely monitors demand for the scarce resource over the next 12 months.

This is according to the city’s water and sanitation directorate’s March 2024 Water Outlook Report released this week, which also highlights the need to swiftly implement its New Water Programme (NWP) that aims to diversify water sources to ensure sustainability of future supply. 

The proposed diversified water sources include plans to develop a desalination plant in the vicinity of the Port of Cape Town, the recycling of wastewater, the drilling of new boreholes, and the sourcing of groundwater from aquifers.

Water experts this week welcomed the plans outlined in the report, which also highlights the risks facing water security – climate change and weather incidents such as drought and flooding that threatens the quality of surface water, as well as rising demand, but have warned that more attention should be paid to the environmental impact of the plans to diversify water sources.

According to the report, initial scoping has indicated that the city’s infrastructure stability programme, which involves refurbishing infrastructure and building new capacity, will require funding of R2 billion over the next 10 years, a sum that has already been incorporated into its budget.

Among these projects is the refurbishment of key pipelines, some of which are more than 100 years old, and the refurbishment of five main water treatment plants to ensure they operate at their full design capacity, which is critical to meet demand to produce an additional 300 megalitres (ML) per day by 2035. Some plants are currently operating at 75% capacity.  

The target of supplying an additional 300 ML per day is in line with the Cape Town Water Strategy (2019) which was implemented after it beat the “Day Zero” drought from 2017 to 2019, when level seven water restrictions would have meant the municipal water supply would be shut off because of water shortages.

Since then, Cape Town’s total water demand has increased steadily from a low point of 500 million litres per day in June 2018, the report noted. During peak demand season in February 2024, demand exceeded 1000 ML per day.

According to the report, the rebound in demand for water after the Day Zero drought has risen above the rate of population growth of around 2% per annum between 2011 and 2022.

“It would appear, therefore, that either the rebound has not ended (most likely), the population figures are underestimated …or there is an increase in system losses, which is considered unlikely. The city will carefully monitor water demand over the next 12 months to see whether the growth in water demand tends towards the population growth rate,” the report noted.

“Should the growth in demand remain above what was projected, it will be necessary to revise the timing of the new water programme, revision of the planning assumptions, or accept a higher risk of restrictions.”

As part of the R2 billion investment, additional infrastructure will also be built to ensure the flexibility and robustness of the bulk water supply system. Work on some of these projects, which are expected to “address the identified backlogs, capacity challenges and constraints” is expected to begin in the 2024/2025 financial year.

According to the report the city’s Bulk Water Master Plan highlights that non-surface water options will dominate future water resources – particularly desalination and water reuse.

National Treasury’s Government Technical Advisory Centre is providing transaction and specialist advisory services to the city to determine the optimal implementation method for the development of a permanent desalination plant.

The advisors considered the viability of the proposed site, which is undeveloped land at the intersection of the R27 and N1, next to the Bidvest container depot in the port vicinity and compared it to alternative sites.

“The transaction advisors reviewed the various mechanisms that can be used to implement this scheme and assessed the city’s internal capacity to implement and operate the desalination plant in terms of Section 78(1) of the Municipal Systems Act (MSA),” the report said.

The findings of the assessment were shared with the city council which granted approval to proceed with a detailed feasibility study of alternative options for the implementation and operation of the plant in March 2024.

“The transaction advisor is currently busy with this detailed feasibility study of the alternative options (including the possibility of a public private partnership). The detailed feasibility study also includes a financial assessment of the different implementation mechanisms,” the report noted.

The environmental impact assessment process has also started, and the project remains on track to deliver approximately 70 megalitres per day by 2030. Other possible desalination sites are being assessed on the West Coast, including Melkbosstrand and Witzands.

The Water Reuse Strategic Study has identified 10 wastewater treatment works (WWTW) sites with potential for water to be recycled for direct potable reuse (DPR) and indirect potable reuse (IPR), while a further 16 were excluded due to a high proportion of industrial effluent or because the WWTW are too small to be a viable, or all the treated effluent has already been committed to other uses. The 10 sites are in Greenpoint, Hout Bay, Wildevoelvlei, Cape Flats, Mitchells Plain, Bellville, Athlone, Potsdam, Fisantekraal and Macassar.

Groundwater is also a critical component of the city’s strategy to diversify its water resources, and an essential resource for developing drought resilience, the report noted. Over the last year, the city has continued with the development and commissioning of all three groundwater schemes, namely Table Mountain Group Aquifer (TMG), Cape Flats Aquifer (CFA) and Atlantis Aquifer. This has included the drilling of more than 10 boreholes.

The report warned that delays in implementing the city’s NWP “will increase the probability of imposing water restrictions, and the city will not deliver 300 megalitres a day by 2030.”

“The likelihood of restrictions, in the short to medium term, exists due to concerns surrounding ageing infrastructure and possible changes in raw water quality. This risk will take several years to address,” the report noted.

“Growth in water demand needs to be carefully monitored over the next 12 months. Should demand growth not reduce, schemes will need to be brought forward, or adjustments will need to be made to the targeted assurance of supply,” the report warned.

Wits University development specialist Mike Muller said it was “good to see Cape town has learnt from its Day Zero debacle”.

“Back then, there was an over-reliance on water conservation, and the development of new supply infrastructure was not prioritised. The current programme to develop infrastructure to increase supply is an essential complement to the ongoing efforts to improve distribution and promote water use efficiency. It’s the only way to ensure resilience to climate variability and change,” Muller said.

University of Cape Town Future Water Institute Associate Professor, Kevin Winter, said  managing future water supplies was far more complex than a decade ago.

“Uncertainty abounds in how climate and weather variability will affect supplies. In addition, the city’s population is growing by 1.6 to 2%, effectively increasing by 1 million people every 10 years. It is about increasing population and per capita water use with lifestyle choices and habits, especially during long, dry summers,” Winter said.

“The city is moving in the right direction with its plans for augmenting its water programme and advancing its programme for replacing pipelines and ensuring that bulk infrastructure plants are performing at their design capacity,” Winter said.

“I am sure that managers in water and sanitation are nervous about how to raise the capital and operational budget to deal with a pressing commitment to supply at least 300Ml per day by 2030. Worst still is if we suddenly find ourselves in a drought again and far sooner than can be predicted. If so, the city will struggle to bring its master plan and implementation programme forward,” he said.

Winter said the report was “forward-looking and hard to fault”.

Wits University’s School of Civil and Environmental Engineering senior lecturer, Precious Biyela, said the report showed that the city is “in general” adequately preparing to meet future water demand.

“In my view, the biggest risks are ironically those linked to the environmental footprint of these new and proposed ways of ensuring water security. I am of the view that in the same way that the report mentions the monetary cost of such things as infrastructure development,  the report should have been more transparent and direct about the environmental cost of the plan,” Biyela said.

“I am sure that the city’s planners and their advisors have considered these things, so it will be great to see them addressed in future iterations of the outlook report.”