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In 2018, following a historic three-year drought, the water sources in Cape Town, South Africa ran dry. It was the first major city to face Day Zero: when you’d turn on the faucet—and nothing would come out.
The town leaders discussed expensive, environmentally disruptive projects like pipelines and desalination plants. But then an environmental nonprofit, the Nature Conservancy, proposed a radically different approach that could win Cape Town 13 billion gallons of water a year, cheaply and perpetually, using a method that worked with nature instead of against it. All they needed was a helicopter, some ropes and saws, and some of the poorest women in Cape Town.
Guests: Louise Stafford, Director of Source Water Protection in South Africa, The Nature Conservancy. Thandeka Mayiji-Rafu and Asiphe Cetywayo, Greater Cape Town Water Fund tree-cutting contractors.
Unsung Science: Cape Town Drought
In 2018, Cape Town, South Africa became the first major city to run out of water. The drought was so bad, nothing but muddy water came out of your faucet.
Louise The residents would go and collect their daily supply of seven gallons of water every day, seven gallons of water per person per day.
So the scientists at a nonprofit proposed a solution that worked with nature instead of against it. All they needed was a helicopter and an army of women with chainsaws.
Thandeka Those areas are very mountainous. Verrrry steep. Very steep. So just imagine.
And here’s the crazy thing: It worked.
I’m David Pogue, and this is “Unsung Science.”
Season 1, Episode 10: How women with chainsaws saved Cape Town.
That would be Cape Town, South Africa, a rapidly growing city of 4.7 million people.
The continent of Africa looks like a dog’s head, nose down, like it’s drinking from a bowl. Well, it looks like that if you squint. And you haven’t had much sleep. There’s even a lake where the eye should be—Lake Victoria.
Anyway, Cape Town is on the southernmost tip of South Africa, on the west side. It’s basically the dog’s mouth.
It’s a gorgeous, gorgeous city. I mean, it’s parked right at the union of two oceans, and it’s bordered by majestic mountains. It looks like a CGI city somebody made for a “Lord of the Rings” sequel or something.
Anyway, like everywhere else on earth, Cape Town has been feeling the effects of the climate crisis. The city’s water comes from its mountains. In the winter, it rains, and the water runs down the slopes into six huge reservoirs.
In 2014, the reservoirs were in great shape—97% full. But that year’s rainy season was a not-very-rainy season; the reservoirs fell to 71% full.
Hmm… could this be anything to worry about?
2016: Another dry rainy season. Now the reservoirs are 60% full. Uh-oh.
2017: 38% full. That got people’s attention. Especially when that summer was baking hot and brutally dry. The city logged six inches of rain over the entire year 2017—that’s only 2 inches more than the Sahara Desert gets. The news wasn’t good:
News: Last year was one of the driest on record here, in the midst of a 3-year drought that officials say was impossible to predict.
By the beginning of 2018, the reservoirs were below 20% full. The biggest one, the Theewaterskloof reservoir, usually supplies about half of the city’s water; it was about 12% full. You can find pictures on Google. It looked like a huge, gross, sandy mud puddle, with these naked branches sticking up from what once had been the underwater floor.
And keep in mind that at about 10%, the reservoirs are basically worthless; the dregs of that water are too muddy to be useful.
Cape Town was becoming the first major city in the world to completely run out of water. The countdown had begun to a scenario called Day Zero: when you’d turn on the faucet—and nothing would come out.
Newsman: The city has entered a phase where it is anticipated a real possibility of Day Zero.
Nobody could talk about anything else.
Helen Zille video message Jan 2018:
Zille: “The projection is that Cape Town will run out of water sometime early in April. That means you have to save water as though your life depends on it.”
This is Helen Zille, premiere of the Western Cape district, in a 2018 news broadcast.
News: There are fears of anarchy and chaos as people, of course, begin to scramble for water. Have you talked about how that will be managed?
Zille: Yes, absolutely. There’s a safety and security plan, involving the Metro police, the police, private security, and the South African Defense Force.
If anyone understands Cape Town’s water situation, it’s Louise Stafford. She’s the Director of Source Water Protection in South Africa for the Nature Conservancy. She’d spent decades studying and managing water use in Cape Town, but she’d never witnessed anything like this.
Louise Agriculture was really affected quite badly. Many farmers lost their farms, and over 33,000 people lost their jobs on farms in the Western Cape or in this region. They have extended families. It’s whole all households that’s being affected.
DP So what —what did it feel like among the residents?
Louise There was elements of people saying, “This is a conspiracy theory.” Then you get a portion of the communities that felt really fearful with that reality. The majority of residents in Cape Town really was really concerned about it.
As of February first, 2018, you weren’t allowed to use more than 13 gallons of water per person per day. 13 gallons to cover everything: Drinking, cooking, showering, laundry, toilets, dishes, pets—everything. Get caught using more than that, and you’d be slapped with fines up to $700.
And if you had trouble even getting water…the government was happy to help out.
Louise The residents would go and collect their daily supply of seven gallons of water every day, seven gallons of water per person per day. There were about 200 pods, what they call pods, those temporary places. It’s almost like little gas stations where we would have to queue every day to get our daily supply of water.
Standing in those queues to fill up your water jug every day wasn’t just inconvenient; it was a major disruption to your day.
Louise: In addition, you know, children need to get to school, people need to get to work. And now you have to queue for your daily supply of water.
If you live in the U.S., you probably grew up taking water for granted. You consider it basically free. I mean, if you told someone from, like, Kenya that we take thousands of gallons of purified, filtered, chlorinated, fluoridated drinking water —and water our lawns with it…flush your toilets with it…they’d think we’re crazy.
But during the Day Zero episode in South Africa, water became incredibly precious.
Louise It became a status symbol to have a dirty car because it shows that you’re complying, and you are not wasting water. We couldn’t water our gardens. Many people just lost their lawns.
Radio and TV ads played, offering tips to save water:
Woman: We only flush after every three pees in our house. (laughs).
Woman: I make sure to boil just one cup of water, instead of filling the kettle to the max.
Ad: I save water …By not doing the dishes. If you lick the plates clean, then they look clean, and you can use them again.
Woman: Water is a limited resource, so we should all be aiming high to save it.
To take a shower, you’d stand in a plastic bin to catch your runoff. Later, you could lift up the bin and carry it over to the toilet to use for flushing. You didn’t wash your hands with soap and water; you used hand sanitizer. Women got shorter haircuts, so they’d need less water to rinse out the shampoo. If police caught you washing your car with municipal water, they’d hit you with a fine—and they’d confiscate your hose and your buckets, so you couldn’t do it again.
Pop singers recorded free, two-minute versions of their hits—just long enough for the two-minute showers the government encouraged citizens to take.
This YouTube video from The Guardian profiled more citizen tactics:
Man: “We had to take all the grass out. And this is the plastic grass, which has become very common in the neighborhood and everywhere. Plants that require water is just a no-no.”
Guy: If it’s yellow, let it mellow. If it’s brown, let it drown. Yeah, that. It’s a mess. It’s terrible. I hate it. (laughs)
In the end, Day Zero didn’t refer to one particular day. It referred to the whole period of desperate restrictions and panic. It lasted for about six months—and then finally, finally, it rained. The restrictions had made the water last just long enough for the rains to start refilling the reservoirs. Here’s Louise again:
Louise: And when it started raining that winter, so we received 70 percent of the rain, so it brought that relief. So it’s a combination of water savings, more weight of water, rainy seasons.
The city of Cape Town celebrated with TV ads.
Ad: It was tough. But together, we’ve refused to waste water. Now we’re the #1 water-saving city in the world. Come and see for yourself. It might just change the way you think about water.
But Louise says that Cape Town’s water emergency still isn’t over.
Louise We cannot say that the crisis ended. because we didn’t up until now, since the 2018, not one of the years, not one of the winters, Cape Town had its hundred percent rainfall. It’s on average between 70 and 80 percent of our annual rainfall that we had since, since 2018. That’s the first thing that we should know.
The second thing is that the population in Cape Town increases. The population is growing.
The Cape Town drought was the worst in 100 years. But everybody knows that it won’t be the last. Even during the Day Zero episode, city leaders held urgent meetings to consider ways to avoid another crisis. They launched construction of two desalination plants, designed to convert sea water into drinking water. They began digging deeper to reach even more remote aquifers—underground water stores.
And—even before the crisis was over—they were meeting with The Nature Conservancy, the nonprofit environmental charity where Louise Stafford works. They had a crazy idea that could buy Cape Town two months of water a year, cheaply and perpetually, using a method that worked with nature instead of against it. All they needed was a couple of helicopters, some ropes and saws, and some of the poorest women in Cape Town.
After the break, I’ll tell you about it—and whether it worked.
As you now know, the 4.7 million people who live in Cape Town, South Africa, get their water from the mountains around the city. It runs down and eventually flows into six giant reservoirs—that by February 2018, were essentially empty.
Thandeka: We were quite panicking. I don’t want to lie to you.
That’s Thandeka Mayiji-Rafu, who lives in a small town near Cape Town.
Asiphe: [00:10:40] You would open your tap, and then you would get water that smells muddy. Sometimes the color of the water, you would see that it’s brown, meaning that it’s coming straight from the bottom of the river or the dam. So it was really a difficult time for us, really.
And that’s Asiphe Cetywayo. I’ll tell you what Thandeka and Asiphe are doing in this story in just a moment.
Anyway, the first solutions that occurred to Cape Town’s engineers were what environmentalists call gray infrastructure: Stuff you build, like desalinization plants. Pipelines. Deep drilled wells to aquifers.
But Louise Stafford at The Nature Conservancy raised her hand to propose a different approach: Green infrastructure. Work with nature, instead of against it.
To understand the gist of the idea, we need to shift our focus from the city of Cape Town—to the magnificent sandstone peaks surrounding it. These mountains draw a million tourists a year—but they’re also host to a remarkable ecosystem called fynbos. That’s F-Y-N-B-O-S—loosely translated from Afrikaans as fine bush. It’s a narrow belt of incredibly diverse plant life, spectacular weird flowers, shrubs, grasses that give the mountain a sweet herby smell.
According to Louise Stafford, the fynbos is really something special.
Louise It’s got about nine and a half thousand different plant species. Over 70 percent of those plants are found nowhere else on Earth.
As a handy bonus, the fynbos isn’t very thirsty.
Louise: [00:21:33] Because it was evolved over time for this environment, it also lives with the environment. It doesn’t take too much water and it’s in balance.
But something else grows on the mountain slopes around Cape Town—something that shouldn’t be there. Ominous music please?
Thank you. Those mountains have been pretty much taken over by an invasive species that might not strike you as especially evil: Pine trees.
Back in the 1800s and early 1900s, European colonists brought pines and acacia trees to Cape Town and grew them in plantations. They couldn’t very well build their homes and repair their ships with Fynbos shrubs. So they set about growing their own timber.
But in the process, they triggered a classic story of unintended consequences: an invasive species running wild.
Louise It’s human induced. They arrive, they’re without natural enemies. That gives them a competitive advantage, because they can grow without any predators or insects that eat them or pathogens.
So what happens is that the trees, the pine trees escape from the plantations. And it started growing up high up in the mountainous areas.
These pines have huge root systems. They’re incredibly thirsty trees—a single tree can drink 400 gallons of water a day. 400 gallons—remember, the people down below were trying to get by on 13 gallons a day.
Louise: If it rains, the pine tree roots take that water up and —and evaporate. It evaporates and it doesn’t allow the water to get into the streams.
DP So the trees are stealing the water up high in higher elevations mountains before it can reach the city?
Louise Yeah, the invasive trees steal water from high up in the mountains and from lower lying areas where they would infiltrate aquifers and replenish the rivers.
Louise and the Nature Conservancy put together a public-private partnership—a coalition of environmental groups, government departments, and corporate donors—called the Greater Cape Town Water Fund.
Its proposal to the city was simple but incredibly ambitious: Hit Undo on the 150-year-old pine-tree mistake. Cut them all down.
Louise Looking at the trees is a science that’s been coming for a long time. We always knew that invasive trees steal water.
But what is new is the urgency, the fact that the dams and the reservoirs ran dry, the urgency and the realization changed.
DP What was the hardest part of getting this to happen?
Louise The hardest part was to convince a city that was facing a situation of taps running dry …to think beyond the short term of getting of a rainy season and of pipes and reservoirs. But to think that nature can become part of the solution.
DP So the hardest part wasn’t the engineering or getting people into rough, dangerous mountainous areas to cut down trees. It was the people part…the political part.
DP You make it sound like anybody would need to be convinced. I mean, who wouldn’t want an inexpensive nature-based solution compared with building a desalination plant?
Louise I think the reason why is because the figures aren’t there. Municipal manager or municipal water utility, their main function is to make sure that the taps are open. And it’s mostly run by engineers.
How do you convince engineers, whose first instinct is to build stuff, that the better, cheaper, longer-lasting solution is to cut down stuff?
You meet them on their own turf: With surveys and research. In 2018, the Nature Conservancy conducted a study.
Louise: We said, “ if we clear the invasive trees in certain areas, how quickly can we get the water back in the system, and at what cost?”
And the business case, I believe, was a game changer.
The study revealed an astonishing statistic: Within five years of clearing the invasive trees, the city would gain over 13 billion gallons of water …every single year.
Louise The city would gain two months water supply every year if we clear 157,000 acres. Two months water supply every year, into perpetuity, for as long as we maintain the areas.
And by 2050, keeping the invasive trees cleared would gain the city of Cape Town four months of water every year.
And I’m guessing that this is the part that caught the eye of the city engineers: the price.
Louise: Cutting down those invasive trees has shown a return on investment of 351%. In other words, it’s 351% per cent more cost effective to clear invasive trees from the watersheds than it is to set up and manage and operate the desalination plant.
As a handy bonus, clearing the trees is a more or less permanent fix. As long as you stop by every couple of years for a little cleanup, Louise says that…
Louise: It will carry on forever. Whereas if you look at an engineered infrastructure, they have dams or reservoirs have a lifespan, pipes have a lifespan. So one always have to maintain or rebuild.
DP And did nobody say, “wait a minute, this is the first time in history that the Nature Conservancy is suggesting cutting down a lot of trees?”
Louise We understand that it’s important to have trees to—to help with carbon sequestration and mitigate climate change. But if you have the wrong tree, or the right tree in the wrong area—In other words, the tree that doesn’t evolve in an area, and become invasive, the cost of having that tree in a watershed is outstrips the benefit. where we remove trees, we allow the native vegetation to restore. And by doing that, you— you enhance the environment as the natural environment rather than then looking at it just simply removing trees.
Now, you might consider cutting down 250 square miles of pine forest on steep, dangerous mountain slopes, in blazing heat and whipping winds, to be a fairly ambitious project. But Louise and her team decided to make it just a little more ambitious yet.
And to understand the significance of this twist, we have to acknowledge a particular dubious distinction held by South Africa: On the list of the world’s countries, sorted by wealth inequality, South Africa is in first place. Or dead last, depending on how you look at it.
Until 1994, of course, South Africans lived under the legal and political system called apartheid: official racial segregation and economic discrimination for the benefit of the white population. Strict laws literally dictated separate neighborhoods for each skin color. If you were black, you lived in what are called townships: very poor, ramshackle, crowded neighborhoods, on the outskirts of town.
Apartheid ended 27 years ago—but the townships are still there. Each neighborhood does have running water now—a single public spigot out by the road. They have toilets, too: one porta-potty for each dozen families or so.
Now you have the context for the choice of workers that Louise and her team chose for the tree-cutting project:
Louise We target women and young people under 25. And through creating these job opportunities, we improve livelihoods. We help alleviate poverty. We give additional skills and dignity to people who don’t have work.
That’s right: The plan was to hire women—poor women—from the city to do the work.
Louise So the added benefit of the work that we do is job creation and poverty alleviation.
DP Wasn’t that considered an added complication to an already complicated project? Because you’re— you’re hiring people who have no experience in forestry.
Louis: But people are highly trained. We make sure that safety is first. And we’re really very excited about this opportunity that’s been created for small businesses and for women.
Here’s where Thandeka and Asiphe come in. They were among the workers hired to undertake the tree-cutting on Cape Town’s mountain slopes.
Thandeka When I started with the program, I didn’t have any other job. I was always jobless, so I didn’t have a choice. When Nature Conservancy came along, they advertised, and they say they are looking for people that will be doing invasive species clearing in the catchment areas.
Asiphe This is new for me, especially of the nature conservancy. Because in the town that I am from, the only kind of jobs that we could do, it’s farming or in farms. So alien invasive plant removal was the new, was a new project for us.
Thandeka was hired as a contractor, charged with building a team of other women to join her up on the mountain.
Thandeka: I’ve got chainsaw operators, the people that are operating the machines, ladies operating machines.
David This idea of hiring women is not something that might occur to a lot of people.
David Are there some ways that you would rather have women on your team than men?
Thandeka We do need men in our teams, but I prefer more ladies than men. I’m not —I’m not like a feminist, but they are loyal. I don’t want to lie to you. They are very loyal. And they are so reliable. Women are reliable.
The people that can stand on anything are women. I promise you. And if things are getting tougher, you will stand with women. Most of them, they are single parents that are the heads of the houses. So even if somebody is —feels like I can give up, who is going to assist?
And so, early in 2018, the work began—to clear 250 square miles of invasive pines from the mountains of Cape Town.
Now, there are no roads up into those mountains. The only way up there—is by helicopter.
The pilot flies each team high up into the mountains, where they’ll live and work for two weeks at a time. They set up low, wind-resistant pup tents, with solar panels to power the radios and lights.
They use clippers to snip the baby invasive trees; chainsaws to cut down the ones they can walk to; and hand saws to cut the ones on steep slopes or sheer vertical walls. (It was considered inadvisable to equip workers with chainsaws while hanging by ropes from the cliff side.)
The process begins with training, where Thandeka introduces prospective workers to the work they’re signing up for.
Thandeka It’s sort of an orientation. You teach the person about their job, from, from the beginning. And you do some awarenesses about like snakes, the steep areas that you are working—going to work on—
David It sounded like you said snakes. (laughter)
Thandeka I did mention snakes, because when you are working in the veld, there is snakes.
That word there is veld, V-E-L-D. It’s the Afrikaans word for field—in this case, the work areas up on the mountain.
Thandeka You must be aware that there will be snakes. you must also be able to identify the snake. What kind of a snake that you saw? Also how poisonous is the snake? Even if maybe somebody has been bitten by the snake, you must know what —what was what kind of snake was it?
And do you know what they teach them to do to a snake when they find one? Nothing.
Thandeka You can’t beat the snake, because the snake belongs in the velds. That’s where it belongs. You can’t take anything from the velds. And you mustn’t chase snakes as well.
David Wow. So they’re not allowed to hurt the snake?
Thandeka No, they are not. They are not. We are we are conserving the nature. because it’s their territory. It’s us that are coming to them, in their own space.
David OK, well now the good stuff. Tell me about the work.
Thandeka OK, all right. In the morning, the team leader or the crew leader, will brief the people about the hazards on the site and which area, then they will present the plan of how are we going to tackle the site?
[radio sounds and preparations run under]
Then after that, they put on the harnesses, it’s a belt, and then they put on all the equipment on, and then the health and safety of the group. We’ll take each and every person before they go that they’ve got everything with them, because it’s safety, safety, safety all the time.
because those areas are very mountainous. They are very high—high areas.
David And steep sometimes?
Thandeka Verrrry steep. Very steep.
David Is it like a wall? or is it just more of—
Thandeka No, it’s like a wall. It’s like a wall. It’s like five-thousand feet from the from— from the sea level. It’s five thousand feet up. So just imagine. Sometimes the ropes that they use, it’s two hundred meters going down.
[sounds of buckle and rope]
David Yes, so are you are you basically hanging from this rope?
Thandeka Yes. Like you can move around, but a little bit from this side to this side and also, yeah, a little bit sideways, but not too much. Just like, for instance, you have a portion that you can clear, like maybe two meters. That’s your area.
David And is your heart just racing, or are you used to that now?
Thandeka When we started the heights, some of them, they were afraid of heights. they are used to it now. Sometimes when they are working, you will even hear them singing.
David Is it chainsaws? Is it —is it handsaws?
Thandeka In some areas where it’s not that steep, they use chainsaws. Otherwise, if the area is too steep, they do a ringbarking.
Ringbarking is removing a band of bark from all the way around a tree, like a belt. Once you’ve ringbarked a tree, it can’t drink water anymore—you’ve basically cut its water-intake pipes—and it dies where it stands.
David So Asiphe, when you’re —when you’re up there, can you give me a list of all the things you have to be careful of?
Asiphe: When you are in the mountain, first of all, you can get into a rock and then you slip and then you fall. It can be very hot, that maybe one worker falls because of dehydration.
Also, you can be up there and then fire starts. And then there’s no escape routes, that you will have to wait for the Rangers to come and get you. And also it sometimes happens that your chainsaw operator is busy cutting a tree, then a worker is passing while the tree is falling, so they don’t see. Also, I can say maybe when one person is busy cutting a tree and then they cut their fingers, like maybe just open a small cut, and then they start bleeding.
There are reptiles up there and there are other animals, wild animals that can be scary. For example, there are baboons and stuff. Those are the things that happens up there.
David OK, I’m never going to complain about my job again. (all laugh)
In 2020, the COVID pandemic slowed the Cape Town work only slightly; the teams cleared 90% of the area they’d targeted for that year. Now, the work is getting back up to speed.
But there have been other Day Zero crises in recent years; Cape Town’s not alone. In 2008, the Spanish drought was bad enough that the city of Barcelona had to import water from France. In 2014 and 2015, São Paulo in Brazil the biggest city in the Western Hemisphere faced a similar crisis; citizens were given water only two days a week. And, Australia, of course, has been in more or less perpetual drought since the 2000s, which led to the devastating 2020 wildfires. Those fires killed over three-billion animals, and burned an area the size of Connecticut, Delaware, Maryland, New Jersey, New Hampshire, Vermont, Massachusetts, and Hawaii—combined.
That’s why, in the last 20 years, the Nature Conservancy has set up similar green-infrastructure projects in 40 cities around the world, producing more water, cleaner water, at a fraction of the cost of building gray infrastructure—and conserving habitats in the process.
By the way, I have no connection to the Nature Conservancy, other than being a fan; I just love the ingenious way they work. They come up with environmental projects that operate within the system instead of against it—devising ways to make it more profitable for stakeholders to conserve land and sea than to continue destroying it.
From a water perspective, the Cape Town project has been a splashing success.
David And how much progress have you made so far? Can you —can you see it?
Thandeka Yes, because in some areas, when we started working there, you could see the area is a wetland, but it’s dry. But now —now that we’ve cleared, it’s damp now. You could see that there is a difference. It is damp.
The water now are running down to the rivers to the dams, to the rivers, because also when —when there is invasive plants, they like to grow like together like this, then the area is dense. So now the penetration of water, it doesn’t go —like easily. But now— now that they are cut down, then the water will penetrate easily.
And from a social and economic perspective—well, here’s Thandeka to bring it all home.
David You spoke earlier about empowering women.
David: Does it work? Do you see growing confidence? Do you see women earning a living?
Thandeka Yes, I can see they, they are —they they are confidence. And also they they, they, they are leadership skills that I couldn’t see before. And yeah, they’ve changed a lot. And also like, they can afford other things that they couldn’t afford before. this program has made a difference in their lives.
David How about your life, Asiphe —any changes?
Asiphe This program has changed me a lot. And also women in my town. For them, it’s like a new life has began. I’ve listened to them when they were planning what they are going to do, how they’re going to achieve most of the things that they wanted in life. So this program really, really changed a lot of people’s lives.
David And the last question, how long will this go on? How long will you keep doing it?
Thandeka At the moment, there is no end point. I will do it as long as I still— I still can, like I’m until my pension. (laughs) I’m— mentoring other people so that it doesn’t end with me.