IN DEEP WATER Are we doing enough to find solutions?
We asked climate scientist Dr Peter Johnston, futurologist Clem Sunter, and City of Cape Town Mayco member Xanthea Limberg for their takes on the water crisis in the Western Cape.
IS DESALINATION VIABLE FOR CAPE TOWN? Dr Peter Johnston
Desalination is magic. You take seawater, pump it into the machine and magically get fresh water. It’s what we call a black box. It’s a process of reverse osmosis: the salt is taken out, leaving you with pure water.
But you first have to get a dam full of water. Our empty dams are nowhere near the sea, so if we want to put seawater in those dams, we have to pump it uphill. This would use a lot of electricity, so cost becomes significant.
Because of the volumes of water we’re talking about, it’s a huge job to integrate desalination with the existing dams.
For the next 10 years, we have enough capacity in the dams. So if it rains normally, we won’t need desalination. If we instal a desalination plant, we must use it. If the plant is not used, people will ask, ‘Why did you waste money building the plant?’
Desalination is a really good option for us if we do it in small quantities. So new suburbs located near the coast could be connected to a small desalination plant that will produce enough for that area. Unfortunately, there isn’t really space for a new suburb near the coast, unless you go up the West Coast. It’s very dry anyway, so it’s ideal to use desalination plants – in fact, they’ve already done so. To construct a desalination plant for the whole of Cape Town is silly. It would cost billions and it’s not going to be needed.
Desalination is used in the Middle East and Australia to make up for the shortfall of water caused by lower average rainfall, which is mainly due to climate change. Both Perth and Adelaide have desalination plants.
I think the City has estimated that a plant capable of producing 500 million litres a day, which is the target being set by Cape Town at the moment, could cost as much as R16 billion, plus more than R1 billion a year to run. But it’s much better than running seriously short of water.
The city’s water and sanitation department has a 30-year water supply plan and desalination is listed as an option. Given the fact that we’re a coastal city, it would be the most obvious part of the broader solution. We haven’t implemented desalination yet because it hasn’t been required. It comes at a massive capital investment cost and there are also major operating and management expenses. We’d have to factor in and introduce this in a manner that is sustainable for the City, as an organisation, but also for residents who are carrying the burden of some of those infrastructural costs.
To minimise the impact of continued drought, we have a water resilience task team, made up of technical officials. We’re also in the process of establishing a water resilience committee, which will be made up of external advisory experts from academia, and business sector bodies, and desalination will be unpacked.
The City believes we need to focus on becoming water-sensitive and water-resilient. The new normal is water scarcity and we’re adequately planning for that. We’re looking for solutions that will provide between 100–500 million litres of water a day. We put out a request for ideas and information to understand what options there are in terms of alternative funding models and mechanisms to finance something like a water desalination plant, and to explore whether rental options are available. We’re considering rental options so the infrastructure doesn’t go to waste when there is adequate rainfall. We’re also considering the financial burdens and impact, and the longevity of a plant of that nature.
IS DRILLING INTO AQUIFERS AN OPTION? Dr Peter Johnston
So what’s an aquifer? Is it a big dam that runs under the surface that we can tap into? Is it a big hole in the ground that is full of water, like a cave?
The answer is no. It’s water trapped in the rocks under the surface that’s possibly available. If you dig a borehole, water flows under the rocks into the little hole and you can pump it out. We don’t know how long we can keep doing this because nobody can work out how much water is down there. The Cape Flats is exposed to an aquifer. The level rises and seeps out of the ground, then you get surface flooding from the water from the aquifer.
If we pump that water out, it has to be purified – it’s being polluted by all sorts of human activity. The City may decide to use that water for grey water purposes, such as cleaning streets or for putting out fires or gardening.
Aquifers have a role, but I don’t think they should necessarily be introduced into the domestic water supply.
There are aquifers in the Cape Flats and under Table Mountain, but if you take too much water away, it lowers the groundwater level and that can create other problems.
We have to diversify our water supply beyond our current base of surface water in dams to desalination, recycling waste water, and drilling into aquifers and other underground water bodies.
IS THE CITY OF CAPE TOWN DOING ENOUGH? Dr Peter Johnston
There are two ways of looking at it. One is the City’s internal process; clearly they’re worried about the situation, and the other is the external process: they don’t want people to panic and think that they’re doing nothing. Internally, they’ve been doing a lot, for a long time. There is the Western Cape Water Management Strategy, which the city is part of. We’ve had three unusually low rainfall years in a row. It’s a one in 100 or one in 50 years’ situation. You can’t plan for that; but you have to deal with it, and the contingencies are the water restrictions, which the City has put in place.
The problem is the situation got worse and restrictions had to get fiercer. People think it’s not their responsibility, so they don’t do it until they’re forced to. The City is working out a supply plan. They now have to wield the stick and keep asking people to use less water. It’s going to be made a lot more expensive so that people actually feel it. Water is never going to be cheap again. I don’t think water should be cheap.
We need information to change the behaviour of people towards water. I think it’s still something that is taken for granted, rather than seen as an increasingly precious resource. Obviously, the City of Cape Town is providing information – they’re sending it out with the water bills, but we need considerably more. We need a weekly drought bulletin. Perhaps some academics who are into water affairs and climate could put this together to give us a feel of how dire the situation is. At the moment, we get the weekly dam percentage and how much water the city has used.
The City has been honest about the current situation. To drive down consumption, we’ve had water restrictions in place for two years. The fact that we’ve been so stringent on demand management shows we have been trying to make people steadily aware of the water crisis. We’ve achieved those saving requirements and have been proactive by implementing restrictions way before the National Department of Water and Sanitation indicated we should. Week on week, we communicate the dam levels on the electronic billboards on the highways, on our website, and through radio and video inserts and media releases.
HOW CAN WE DEAL WITH THIS CRISIS PRACTICALLY? Dr Peter Johnston
The first thing is not to think that because it rains our problems are over. The temptation is to look outside and say, ‘Oh, look how nice and green it is. It’s been raining. I can run the tap a little longer. I can have a longer shower…’
We have to keep thinking about how precious water is. Look at the water bill and try to keep water usage down to less than 87 litres per person per day. It’s not difficult to do that.
The second thing is to look at infrastructure: check whether your garden is water-wise, whether you’re storing water off your roof that’s just rushing away, etc. Some options are costly and some aren’t. A water tank is not going to kill you financially, and if you can use that water, great – but don’t put one up without finding out how to use it.
Lastly, when it does rain, people shouldn’t say: ‘It’s such terrible weather.’ All weather is good – rain is good. Someone wrote that they’d cancelled an event because of bad weather. I said, ‘You didn’t cancel it because of bad weather; you cancelled it because the weather didn’t suit you.’
We’ve got to have some kind of education programme, maybe, as I said, a weekly bulletin, to give people a good idea of where we stand. There’s a lot more that can be done just to show people how they can conserve water.
You’ve got to make people more excited about getting creative. They need to get their own water solutions. It’s all going to require a real change in mindsets and you want that change before you have a shock event.
We’re currently under level 4b water restrictions, which require individuals to consume no more than 87 litres a day. There’s also a water inspectorate unit that goes out to ensure that people adhere to restrictions. We monitor high consumers and have been issuing warning notices, fines and notices to appear in court. All of those interventions will be ongoing. The latest warning notices sent out focused on high consumers who haven’t reduced consumption. We’ve given them time to reduce, and failure to do so will result in the installation of water demand management devices on their properties that will restrict their consumption until it reaches acceptable levels. Of course, we’ll be mindful of the number of people living on the property.
You can also report contraventions via the call centre. And we’ve launched a Whatsapp number for water complaints to ensure that residents monitor one another – a large portion of water wastage happens behind closed doors. It’s your toilets flushing constantly, your showering and bathing, doing your dishes, the amount of water you consume with cooking… the City has very limited control over those things. We’ve broken down what 87 litres of water actually means for you. It means you can flush your toilet only twice a day. We’ve broken down those savings contributions into easy step-by-step guides on how everyone can play their part. I think it’s important for residents to understand that we all form part of the holistic solution.