The City of Cape Town’s Water and Sanitation Directorate’s March 2024 Water Outlook Report underscores the critical need for the New Water Programme (NWP) to diversify the city’s water sources.

The eleventh edition of the report highlights the pressing challenges posed by climate change, population growth, water quality, increased water demand and declining water availability,

It further shows that, with traditional water sources under unprecedented pressure, innovative solutions and diversified water sources are important strategies to secure water availability for a growing city.

The Western Cape Water Supply System (WCWSS) is currently Cape Town's primary water source and will remain so until the (NWP) diversifies the city's water sources, said Water and Sanitation MMC Councillor Zahid Badroodien.

The WCWSS is currently entirely reliant on surface water, sourced from six large dams, namely Theewaterskloof, Wemmershoek, Voëlvlei, Berg River and Steenbras Upper and Lower.

“In light of the seasonal forecast, supply from the WCWSS may become constrained, and is likely to continue to be constrained in a projected drier future,” he continued.

During the 2022/23 hydrological year to October 2023, the WCWSS experienced above-average rainfall, largely driven by two significant storm events.

However, at the time of publishing the 2023 edition of the Water Outlook, the long-term forecasts predicted a dry winter, while, a month later, the reviewed forecasts revealed a wet winter.

“In light of this inherent uncertainty, and learning from the drought, the city continues to take a conservative approach to ensure that early interventions are made,” the report outlined.

“[Further,] there is uncertainty as to the exact scale of the impact that climate change will have on the water resources on which Cape Town relies. It remains to be seen whether climate change will be gradual or be a step-change.”

It is, however, clear that temperatures will increase, resulting in an increased risk of fires and driving increased water demand, and that evaporation and evapotranspiration will increase. Rainfall may decrease, impacting the yield of the WCWSS, and rainfall could also intensify as the system experiences more extreme events and consequent flooding.

“As such, the city has committed to taking action to diversify and augment Cape Town’s water supply and increase water security through investment in NWPs,” said Badroodien, noting that maintaining and upgrading existing infrastructure was crucial for ensuring the long-term resilience and reliability of Cape Town's water supply system.

While the NWP will ensure adequate water is available to meet demand, bulk water master planning has identified several backlogs, capacity challenges and constraints in the short-, medium- and long term.

“Addressing these challenges is equally important as developing new infrastructure to ensure long-term water supply resilience in Cape Town.”

An Infrastructure Stability Programme has been developed and includes the refurbishment of key pipelines, some of which are more than 100 years old, the refurbishment of the city’s five main water treatment plants to recover their full design capacity, and the development of additional infrastructure interventions to ensure the flexibility and robustness of the bulk water supply system to ensure the supply to certain areas is not constrained to individual water treatment plants.

“Initial scoping has indicated that the Infrastructure Stability Programme will require about R2-billion over the next decade to be invested in refurbishing existing water treatment plants. This investment will fund projects aimed at addressing identified backlogs, capacity challenges, and constraints,” he commented.

Through the NWP, the city continues to pursue various water augmentation projects outlined in its Water Strategy, aiming to develop an additional 300-million litres of water supply from diversified sources by 2030.

This will include water reuse, with the implementation of purified recycled wastewater adding 70-million to 100-million litres a day, and desalination, which will yield 50-million to 70-million litres a day.

The clearing of invasive plant species and various management interventions will contribute an additional 30-million litres a day, while leveraging groundwater, through drilling boreholes and tapping springs, will secure over 100-million litres a day.

“Ensuring a reliable and safe water supply is a priority for us. Our NWP aims to diversify water sources and implement sustainable practices to safeguard our water future. By effectively planning for alternatives such as water reuse and desalination, we can ensure that our city remains resilient and is well-prepared in case of below-average rainfall,” Badroodien concluded.