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Residents of Cape Town Are Counting Down to 'Day Zero'

ByAllison EckNOVA NextNOVA Next

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Editor’s Note: This article was originally published in an edition of NOVA’s email newsletter, NOVA Lens, and has now been repurposed for NOVA Next. Sign up for NOVA Lens here (select “NOVA Newsletters”).

Cape Town, South Africa might be paradise at the bottom of the world, but it’s quickly becoming

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the first major city in a developed nation to run out of water.

It’s somewhat ironic, too. Cape Town is generally thought of as a green city, and it has weathered previous droughts without too much struggle. But this dry spell is different. Officials say the city is inching toward a portentous “Day Zero” if no additional rain falls. On that day—April 12—the reservoirs that provide the city with water will be completely parched, and people will have to fetch water at one of 200 collection points to be guarded by the military .

In an attempt to avoid this fate, the government asked Cape Town’s 3.7 million residents on February 1 to start using no more than 13.2 gallons of drinking water a day. The average American uses about 80 gallons of water per day.

This image shows the dramatic depletion of Cape Town’s Theewaterskloof Dam—the largest reservoir and source of roughly half of the city’s water—between January 2014 and January 2018.

“It’s radical. My garden looks like a desert,” said Maura Lappeman, a clinical psychologist living in Cape Town. She says that the city notified residents about Day Zero sometime last year, but only now is reality starting to set in. It doesn’t help that February is Cape Town’s hottest month. “I haven’t taken a bath in two years, and we now have these 90-second showers. Our life is drastically different.”

Cape Town is far from alone. Many cities in California, especially, could have a Day Zero in their future, but the state is doing its best to save water. During its last drought, Los Angeles and several other major Californian cities cut consumption levels by 20–25% . Innovative projects are part of that mission—in particular, Las Vegas’s celebrity “water czar” Patricia Mulroy worked with major hotels on developing laundry-washing techniques that use less water. Now she’s moved on to other states to help them build better conservation practices.

More generally, cities can take steps like promoting use of low-flow showerheads and banning lawn watering or even car washing, said Joan Fitzgerald, a professor of public policy and urban affairs at Northeastern University. “Those kinds of conservation efforts can make a big difference,” she said.

Water quickly becomes political when it’s scarce. For years, Alabama, Florida, and Georgia have fought over water in the shrinking Lake Lanier. But elsewhere, water-sharing agreements have eased hardships, like the one between Phoenix and Tucson , Arizona. (In fact, the World Wildlife Fund has requested that Cape Town establish emergency groundwater sharing by-laws.)

Fitzgerald also points out the oft-overlooked link between water and energy—both how it’s used and how it’s produced. “In the United States, about 40-45% [of water use] is for producing electricity, so when you think about the cooling water needed for coal plants or nuclear plants or fracking and even for natural gas production—that’s a lot of it.” Switching to renewable energy sources like solar and wind, which aren’t as water intensive, could make a difference, she said.

On the other end of the plug, programs that maximize the efficiency of home appliances could save energy and thus water. “Those programs are going to dramatically reduce water consumption in a way that’s not intuitively obvious,” Fitzgerald said.

In the meantime, groundwater extraction and desalination methods are advancing, though they both have their downsides. Groundwater pumping can cause subsidence—cities like Shanghai and Jakarta are sinking because of the pace of extraction. And while desalination unlocks the 97.5% of the Earth’s water that’s salty, it also uses gobs of energy.

Tim H.M. van Emmerik, a water resources researcher at Delft University of Technology in the Netherlands, suggests water recycling as an alternative.

“Re-use of wastewater is something that’s not accepted everywhere around the globe,” he said. “In some places—for example, Singapore—there are plants that clean wastewater directly into drinking water. If astronauts can do it, we can do it, too.”

Could desalination be the answer? Not with most current implementations, but this week, Rachel Nuwer reported for NOVA Next on ultra-efficient solar desalination efforts in Africa. Here’s an excerpt:

Desalination took off in the late 1950s, when engineers developed reverse osmosis membranes. A pump exerts pressure of 600 to 700 pounds per square inch (psi) on salt water, forcing fresh water molecules to squeeze through the membrane, leaving behind a briny discharge.

“The technology is now hitting this inflection point where we can produce water at a much lower cost than you can buy bottled water.”

Today, an estimated 300 million people get some or all of their freshwater from nearly 18,500 desalination plants operating around the world. San Diego , for example, relies on “drought-proof” desalination to reduce dependency on the Colorado River, while Israel has used the technology to transform its nation from water scarce in 2008 to water abundant today, producing 55% of its water from desalination. The results are considered such a success that Israeli scientists are in discussions with drought-plagued neighbors like Egypt, Jordan, and Turkey about exporting the technology, in the hopes that desalination may pave the way for improved diplomacy in the region.

The technology, however, is not suited for every environment. For starters, access to groundwater or seawater is a prerequisite, and desalination can’t be significantly more expensive than other available options. Then there’s the matter of cost and infrastructure. “Will desalination help if it’s the right system of the right size for the right use in the right location? Absolutely it will,” says Yoram Cohen, director of the Water Technology Research Center at the University of California, Los Angeles. “But there’s no such thing as one magic solution that works for all.”


In response to our question , “What did you think of ‘The Impossible Flight?'”, Sally Cluth wrote :

Adidas’ new Futurecraft 4D shoes run for $300 a pair.

Thanks, Sally! It’s true—innovation isn’t a solo adventure. It takes a mind meld to accomplish what the pilots and engineers did in “The Impossible Flight.” That’s why these stories matter, and you’re exactly right that science is a process.


NOVA’s Development Producer David Condon offers this reflection on a 3D printing story he heard about recently:

3D printing first got on my radar about six years ago, when I was doing research for our Making Stuff miniseries. One episode, called “ Making Stuff Wilder ” included the fascinating field of biomimicry, which mines nature for new ways to make things better, faster, and cheaper. It’s a simple yet powerful idea: evolution has been grinding away for about 4 billion years, generating clever engineering solutions to all kinds of problems through a trial-and-error process. Why wouldn’t we make use of all that elegant design?

As it gains steam, 3D printing promises to create a new paradigm for manufacturing, one inspired by nature. For centuries, pretty much all human-made objects have been produced by cutting, bolting, gluing, soldering, or otherwise mashing parts together. 3D printing, part of a larger field called “additive manufacturing,” works more like nature does: by building things all in one piece, layer by layer.

So why talk about 3D printing today? Adidas just announced it’s going to start selling running shoes with 3D-printed midsoles, the shock-absorbing part of the sneaker. Who cares? Well first, I like running and running shoes, and these things are beautiful. Second, it’s an example of the kind of “mass customization” this new technology allows: Imagine sending an image of your foot along with your order, resulting in a perfect fit from your custom-printed sole. And coolest of all, the technology behind this was inspired by the T-1000 robot rising out of the pool of metallic liquid in the 1991 classic, Terminator 2: Judgment Day. Instead of depositing a material out of a nozzle layer by layer, it uses UV light to create a hard polymer as it slowly emerges from a bath of light-sensitive liquid.

What’s different now, versus in 2012, is the context around it. I think additive manufacturing is cool and will result in all kinds of great products. But it has the potential to put many people out of work. Those old assembly lines that connected small parts together may have been inefficient, but they put food on a lot of dinner tables. Today, the workers on those assembly lines are being rapidly replaced by robots. And with additive manufacturing, the assembly line itself could become a relic of the past.

A Hopi Indian hoop dancer

So in a few years when I go on a run wearing my 3D-printed shoes (not yet—I’m way too cheap), I’ll be thinking about two things: how great my bespoke shock absorbers feel; and how we’re going to retrain or otherwise take care of the workers who used to make them.

—David Condon, NOVA development producer

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Is musical truly a universal language? As a self-professed music nerd, I was delighted to see this study in Current Biology investigating whether or not distinctive musical features transcend culture. For example, do love songs always have a certain lilt to them? Do lullabies carry certain rhythms? Take this quiz on The New York Times ’ website to see if you can tell a Rwandan love song from a Hopi hoop dance (see the photograph below).

While the study has been praised by cognitive scientists, it has been refuted by many ethnomusicologists (who study the intersection of music and culture) for overlooking some basic assumptions. They’re saying that scientific inquiry can’t necessarily pinpoint or quantify things like social or political context, which factor into our understanding of what function a particular song or piece plays in a society. Perhaps, then, analyzing music scientifically is a worthwhile endeavor, but broad conclusions can’t be made without consulting those who study cultural context. It’s sort of like human biology—we have to take both genetics and environment into account. In this case, there are a lot of factors that go into what makes a song or piece serve a certain role, and analyzing those factors from multiple perspectives is better than looking at it from just one.


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See you next week,

Allison and the NOVA team

Photo credits: NASA, Adidas, Alexander C. Kafka / Flickr (CC BY-ND 2.0)

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