Residents of Cape Town have managed to halve the amount of water they use compared with six months ago in what has been described as a “remarkable” effort.
City of Cape Town Utility Services: Water and Sanitation director Peter Flower this week said people had completely changed their way of thinking, helping Cape Town to survive the drought.
Neighbourhood groups had also worked together very effectively to drive down demand.
“It was essential for us to get through this. We are now well below the winter consumption rate before restrictions started,” Flower told African Utility Week in a special panel which focused on Cape Town’s water-saving culture.
Flower said the city deliberately focused on the residential sector, as it made up 70% of its total water consumption. Most people took this very seriously, while water management devices were installed for people who exceeded the limits.
He said the city had to rein in people who “felt they could afford to pay whatever we charged them”, as well as some people who were not paying for water and did not realise its value.
The flip side of the water saving is that the city needed to recover what it had lost in revenue.
“By halving our sales, we had to double the tariff to retain the income stream. Punitive tariffs discourage high water use and support a sustainable water service,” Flower said.
He also outlined why temporary desalination was sidelined as a viable option in favour of groundwater exploration and demand management.
“Augmentation schemes are a far more expensive source of water than runoff from rainfall. The cost of treating water conventionally is R5.20 per kilolitre compared to a short-term temporary desalination cost of R40 per kilolitre."
He said that, even with short-term desalination, companies could promise to get a plant up and running in a very short space of time, but “you could only get it a year later”.
“You cannot build infrastructure quickly and in a short enough time to get you through a drought.”
Flower said the city was still “fully committed” to building a desalination plant on a permanent basis, but with a much lower unit cost than temporary plants or barges.
“We’re looking at between R12 and R18 per kilolitre for a permanent basis. This would also be more effective and reliable.”
Flower said an optimum size for a plant which would suit the city would be one producing between 120 and 150 megalitres a day. It was considering the public–private partnership route, which would relieve it of arduous supply chain management constraints.
In the long run, the re-use of water would become increasingly important. He said many of the city’s wastewater plants were treating effluent.
“At plants where we have membrane technology, we disinfect it and send it out for use in industry and recreational facilities like golf courses.”
The city’s Water and Sanitation department has also announced that contractors will start rolling out pressure management technology to certain areas in Cape Town this week. It has identified 25 areas across the city that could benefit from the technology.
“Not only does pressure management generally lower consumption by reducing the rate at which water flows to properties, it also reduces leaks and pipe bursts by better ensuring that pressure remains within levels that the pipework can tolerate.”