Day Zero still looms in the Cape
Winter rain is falling in the Cape but experts warn it’s not nearly enough to stave off a water crisis next year
BLURRY snaps of rain-spattered windscreens, pictures of grey skies and open umbrellas – these days when it’s raining in Cape Town the whole world knows about it because it instantly triggers a deluge of weather-related posts on Twitter and Facebook.
With the city narrowly avoiding Day Zero – the day the taps were due to run dry – it makes sense that residents want to share their sense of relief. So does this mean they can celebrate by taking a hot bath instead of a bucket shower?
Not so fast – the rain hasn’t washed the crisis away, it’s merely postponed it, say city officials and weather and water experts. With serious concerns around rainfall prospects and dams remaining at crisis levels there’s still a threat that Cape Town could become the world’s first major city to have its taps run dry. Here’s why everyone should be worried.
JUST A DROP IN THE OCEAN
After three years of below-average rainfall the Cape Town metropole – where most people in the Western Cape live – has pinned its hopes on the winter rain to help it play catch-up. But based on rainfall figures so far, it seems hopes for an above-average year were in vain.
Hydro-climatologist Dr Piotr Wolski at the University of Cape Town’s Climate Systems Analysis Group (CSAG) spells it out.
“In March we could’ve hoped for a wet year. Now we know it’s unlikely,” he says.
Figures going all the way back to 1930 show that the amount of rainfall by the end of April gives an indication of what kind of rainy season can be expected. If that rainfall is above average, there’s a good chance the rest of the season will also be above average.
But sadly it seems we’re in for another below-average year. The SA Weather Service says the long-term average for its Kirstenbosch station in April is 88,3mm. This year it was at 75,4mm.
Then there’s the especially significant example of Theewaterskloof, the biggest of the Western Cape dams serving the metro. Only 19,1mm has been recorded there this April, compared with the longterm average of 56,4mm, according to the City of Cape Town.
Based on the rain so far, Peter Johnston, Wolski’s research colleague, recently told News24 there’s only a 5% chance that the metropole will receive substantially above-average rain for this year – which is exactly what’s needed to avoid the dreaded Day Zero.
Dr Willem de Clercq of the Stellenbosch University Water Institute is also predicting Cape Town won’t have above-average rainfall this season – but he thinks the annual rainfall will be higher than in the past three dry years.
“We’ll only be able to tell by the end of July whether we’ll have enough . . . because that’s usually when rainfall starts declining again,” he says.
DAM LEVELS
By the middle of May, water levels in the six main dams that supply the metro and other parts of the Western Cape were sitting at an average of 21,4% – compared with 72% at the same time in 2014. The province as a whole is doing worse, with dam levels at an average of 16,9%.
And to make matters worse, after the first May rains, water consumption in Cape Town increased by 6,7% to 554 million litres a day in the week ending 14 May. That’s 104 million litres more than the savings target of 450 million litres a day set for the city by the national department of water and sanitation.
A projection in the City of Cape Town’s Water Outlook report forecasts the metro can avoid Day Zero in 2019 if this is the scenario: if winter rain is 85% of 2017’s rainfall and collective use is limited to 450 million litres a day, dams should be on average about 32% full by October, and by June next year dams should be just above 13,5% full – the level at which Day Zero would take effect.
But if citizens ignore the problem and allow their usage to creep back up to, for example, 600 million litres a day, dams
could hit the 13,5% mark as early as February or March next year.
Water will be an issue in Cape Town for many years to come, deputy mayor Ian Neilson warns.
“The situation remains serious,” he says. “It’s not possible to predict how much rainfall we’ll get. Even if we get aboveaverage rainfall, which is unlikely, our dams will take years to recover.”
BACK-UP PLANS
The city has been developing plans to bolster dwindling dam supplies. Butthese augmentation schemes, which include the construction of desalination plants and harvesting groundwater, will boost water supply by only 12% in the short term, according to the Water Outlook report.
Although the Western Cape water supply system’s next augmentation project, which will relay water from the Berg River into Voëlvlei Dam at about 60 million litres a day, has been fast-tracked it’s unlikely it will be completed before 2021.
So Cape Town, which gets more than 90% of its water from dams, will still be heavily reliant on dam water.
Current and short-term augmentation projects include a plan to harvest 150 million litres of groundwater a day. Of this, 80 million litres a day will be from the Cape Flats aquifer, 20 million litres from the Atlantis aquifer, and later also 50 million litres from the Table Mountain group aquifer. In addition, 16 million litres a day will come from temporary desalination plants and about 10 million litres a day from temporary reclamation schemes. The metro is also investigating permanent, large-scale desalination. The most cost-efficient option seems to be a plant that produces 120-150 million litres a day. A large reclamation plant that would produce 70-90 million litres a day may also go into operation by 2020.
PROPOSED TARIFF HIKES
Residents were up in arms when the City of Cape Town announced steep water tariff hikes to make up for the shortfall in revenue caused by the drop in consumption.
In terms of the plan, households using less than six kilolitres were going to be charged an extra 55% on their rates bill. It was seen as a slap in the face for waterwise consumers and there was such an outcry that the city had to go back to the drawing board.
In terms of the new proposal, households using less than six kilolitres a month will pay 10% more – so from paying R26,25 a kl they’ll now fork out R28,90 a kl. If monthly usage exceeds 10,5kl it will cost R120,27 a kl, and if it’s more than 35kl, a punitive tariff of R1 000/kl kicks in.
The city insists it needs the money to continue existing water services and finance its water-augmentation plans. Whereas it costs about R5,20 to bring a kilolitre of dam water to taps, a project to set up a temporary desalination plant sees this rocket to up to R40 a kl. It’s an expensive business – and unfortunately it’s the consumer who has to pay.
THE NEW NORMAL
Experts say a key reason Cape Town’s taps didn’t run dry this year was because many residents heeded the call to limit water consumption to 50 litres a day.
“What’s now needed is to sustain it until better rains come,” Wolski says.
He warns people not to think the city’s water-augmentation plans will magically take the problem away.
“Augmentation is problematic because of scale,” he explains. “You can’t replace within a year a water supply system that was built in the course of a century. There’s some progress on the augmentation side, and that should create some security in the next year. But sustained low demand remains the key.”
De Clercq adds that because Cape Town is such a fast-growing metro there’s a chance that water will continue to be a problem for years to come.
“That’s why we encourage people to make long-term adjustments to their water use. For example, people need to adapt their gardens and get enough rainwater storage tanks linked to their household supply so they can use that water directly in the home.”
He reckons if enough people choose to go that route, it can significantly ease the pressure on dams.
‘In March we could’ve hoped for a wet year. Now we know it’s unlikely’