City of Cape Town’s water and energy efficiency strategist Sarah Rushmere today revealed just how stressed the greater Cape Town water supply system is.
Speaking at a water-themed hackathon event at Woodstock’s Rise Cape Town, Rushmere revealed that even with the City’s current water restrictions, system maintenance and other measure in place, Cape Town still isn’t saving enough.
“People are using a third less water than they would a few summers ago. But it’s not enough,” she explained.
The city, which is currently under the blanket of Level 3B water restrictions, has just 28% capacity remaining in its 15 dams at the last count. More worryingly, just 18% of that is fit for consumption. These numbers are however pointless without context.
The City has faced droughts before — notably and most recently in 2009 — but the City cannot predict when the seasonal rains will begin this winter.
“The oceans haven’t sent the signal yet,” she quipped, citing meteorologists working with the City.
‘Intermittent supply’ will be implemented by the City of Cape Town if water storage dips below 15%
Additionally, 40% of the Western Cape’s combined catchment supplies the City of Cape Town with 40% of its water, with households in turn using between 50-60% of that total.
At present, current water consumption rates — which is well above the 700-million litres per day threshold — suggest that the current water stores will be flushed by June 2017. Current water restrictions hope to extend this deadline by another month.
Procedures are in place to alleviate the impact on citizens and to further save water. Rushmere explained that an additional 24 maintenance teams have been deployed in the city to fix leaks and other issues, while plans earmarked for 2020 have been brought forward in light of the drought.
If these measures don’t lessen the problem, the City does have a backup plan.
Below 20% storage, the City will “decrease water pressure in the network” and will increase the severity of water restrictions. Below 15%, “intermittent supply” is planned. Beyond that, the City of Cape Town will enforce “lifeline water supply” measures, which will involve “minimal supply pressures, intermittent supply, and very stringent restriction measures”.
On a long term basis, desalination is an “option” alongside others for the City, Rushmere explains, but “it’s the cost of the technology” that’s the inhibitor. And the cost for a plant, you ask? R15-billion.
The Water Hackathon will run until Saturday afternoon at Rise Cape Town, during which entrepreneurs will brainstorm possible solutions to the Cape Town water crisis.