According to the City of Cape Town’s water dashboard on Monday June 15, the aggregate dam levels for the City’s water supply dams stood at 21.2%. Since the last 10% of water in a dam is difficult, if not impossible to abstract {this is the correct term}, this means that we have 11.2% left, which at current consumption levels, equates to 98 days of usable water.
Depending upon who you talk to at the City of Cape Town, responses to the question “What happens when the taps run dry?” range from “We’re praying for a miracle” to “We’ll move water to strategic locations by tanker truck” to “We don’t have a plan. Basically, we’re f****d.”
Even if we could stick to the daily consumption target of 600 million litres a day, that is still a prodigious quantity of water which must be collected and distributed. Assuming that only drinking water is trucked in, say 20% of daily consumption, that is still a well nigh impossible task.
Do that maths. If a tanker truck carries 200 000 litres, 12 million litres of drinking water equates to 600 trips per day. And once a tanker arrives at its destination, what then? It can’t deposit the water somewhere. It will have to wait while people painfully slowly fill whatever vessels they have in which to carry drinking water.
Whereas the human body can do without food for between 21 and 28 and days, it can only survive between three and four days without water, but that presupposes that it is not overly hot, and that you do not exert yourself.
Human nature being what it is, the need for water will make people cranky and difficult.
If there is any hint that somebody is taking more than their faire share, tempters will flare and it could get very ugly.
If you’ve never been in a situation where the availability of drinking water is severely curtailed, you have no idea what to expect.
The talk of accelerating the Berg River Voëlvlei augmentation scheme is a red herring. All the scheme will achieve once it is operational, is to pump water from the Berg River to the Voëlvlei Dam, which equates to moving deckchairs on the Titanic, even assuming that you have sufficient water flowing down the Berg River to actually abstract, and as things stand now, that is simply not the case.
This project is expected to come on stream in 2021.
The City is also moving ahead with the purification of waste water to potable standards, a project that will yield 100 million litres a day, but that will only come on stream in 2023.
The other narrative is acceleration of the project to tap into the Table Mountain Group super-aquifer, the subject of a 10-year-long joint study, only set to come on stream in 2024, and in a limited capacity at that. Just how much it can be accelerated is unclear.
Desalination is also being touted as the solution to our current problem.
The ecological impact of a plant large enough to produce half the metropole’s daily water requirement – about 300 million litres – will be significant.
For every one litre of potable water, between three and four litres of brine, laced with chemicals needed to make the desalination process more efficient, must be returned to the ocean – between 900 million and 1.2 billion litres a day.
Best estimates indicate that it will take at least a year to construct the plant.
This estimate assumes all environmental regulations are suspended, in consideration of the exigency of supplementing water supply, obviating the need for an environmental impact assessment and record of decision process, which routinely takes two years or more.
Such a desalination plant will cost about R4.5 billion at current exchange rates, which the City will either have to find, or contract with a supplier that is prepared to build the plant on risk, and supply water to the City at a rate per kilo-litre, which will include the amortisation cost of the plant.
What that will do to the price of the water, is unclear.
None of these measure will do anything to alleviate the current crisis, but how likely are we to actually run out of water?
Well, at the Western Cape water indaba at Goudini, Worcester, last week, the experts noted that whereas their current forecasting models suggest that we ought to have a winter slightly wetter than last year, the impact of climate change has reduced the confidence level in their predictions to the point where they are not able to predict with any certainty, what our rainfall is likely to be.
On Monday Premier Helen Zille declared the Western Cape a disaster area because of the water crisis, launching project Avoiding Day Zero, which will focus on demand management, winter conservation, and groundwater management.
In the meantime, it is up to us, to make our remaining water last as long as possible.
By using as little as possible, for everything we normally do with water.
Drink what you need to remain hydrated, but in every other aspect of daily life, there are ways in which to cut water consumption.
The City reckons daily per capita consumption should be limited to 100 litres, but if we all make an effort and aim for 50 litres a day, our water will, in theory, last twice as long.
As the City said in its press realease last Monday announcing the advent of level four water restrictions: “This is not a drill.”
