These Nets Harness Water From Fog

Fog-collecting CloudFisher nets on Mount Boutmezguida, Morocco.
Fog-collecting CloudFisher nets on Mount Boutmezguida, Morocco. Photo: Copyright aqualonis

Mount Boutmezguida, a mountain in southern Morocco that is part of the Anti-Atlas range, gets less than 5.2 inches of rainfall a year. For context, last year New York City got 45. The region is still feeling the effects of a devastating drought in 1986, compounded with increasingly frequent drought cycles due to global warming.

Historically, local communities have collected rainwater in household cisterns, and supplemented their water supply in the summer months by collecting water on foot from wells as far as three miles away. Over the past few decades, however, cisterns and wells have begun to run dry, with most households now having to buy water to be delivered by truck, even during the wettest months.

What Boutmezguida lacks in rainfall, though, it makes up for in fog. Thanks to the cold air current coming off the Canary Islands mixing with the high-pressure Azores High system over the Atlantic Ocean, just off the coast of Morocco, there is an abundance of stratocumulus clouds that hang low to the ground, enveloping the mountain in a thick coat of fog.

And so, in a nation that is leading the push for renewable energy in Africa, it’s no surprise that a local organization has taken stock of the natural resources and found a new way to bring water directly into households — by harvesting fog.

It sounds futuristic, but the practice of harvesting fog can be traced back to precolonial times on the Canary Islands, a short 62 miles offshore from Morocco. And the technology being used, in the simplest terms, is pretty easy to envision — giant nets collecting precipitation from fog into troughs, that then use gravity to send pure, potable water through miles of piping and straight into people’s homes.

The first modern fog-harvesting nets were built in the Atacama Desert in Chile, after a severe drought in the 1950s. A retired physics professor from the University of Chile started experimenting with sheets of nylon as a way to collect condensation, and found that fog could provide sustainable water alternatives for desert communities. The nets in the Atacama Desert are now more sophisticated, and the water is used not only for homes, but also to brew beer for a local brewery.

When Dar Si Hmad, a nonprofit based in Sidi Ifni, in southwestern Morocco, first learned about the fog nets in Chile, members immediately thought of their own Mount Boutmezguida, which averages 143 fog-coated days a year. Dar Si Hmad was originally founded to promote educational opportunities and strengthen basic infrastructure in the region, but its members recognized the increasing importance that renewable resources would play in years to come, and the basic necessity of more sustainable water practices in local communities.

“It was started with the idea that we need to have a much larger kind of reach with many issues, infrastructure and education being our most important,” said Jamila Bargach, the director of Dar Si Hmad.

They created a new branch focused on fog research, and in 2006 began studying the possibility of bringing fog nets to the mountain. After pairing with WasserStiftung, a German organization that works to provide clean and accessible water to communities around the world, the first nets were installed in 2013.

The nets themselves are large, standing almost 20 feet tall with four mesh panels that span a combined 581 square feet, and held up by metal frames anchored to the ground with steel cables. Condensation builds up on the mesh netting and drips into a trough below, which is then funneled into reservoirs through a vast network of piping. While fog collection varies depending on the time of year, in June nets regularly produce 50 liters a day.

During the first iteration of the fog harvesting project, Dar Si Hmad ran into a major problem. Winds on the mountain can reach up to 75 miles an hour, and the nets were being severely damaged. The mesh panels were frequently ripped, and the poles would be bent out of shape, forcing Dar Si Hmad to replace nets every three or four months.

Each time the nets needed to be replaced, Dar Si Hmad faced the logistical nightmare of getting parts imported and then transported up the steep mountain. WasserStiftung went back to the drawing board, and engineer Peter Trautwein created CloudFishers, fog nets that can withstand the winds on Mount Boutmezguida. While designing the new nets, he also kept future maintenance in mind — the CloudFisher nets only require a wrench and a socket wrench for all assembly and upkeep.

At first, local communities were skeptical.

“Having the water from fog was a bit of a stretch for them in the beginning,” said Bargach. Fog had long been a nuisance, seeping into homes and clothing to create a pervasive dampness that was seen as something only worth enduring, not celebrating. “It was difficult to have the communities be part of the implementation, because of their attitude towards fog as being something negative, not a positive.”

All it took to get locals on board, though, was turning on the first tap. The project began by servicing four villages in 2015, but word spread quickly and now around 800 people in 15 villages have fog water pumped directly into their homes. With 5,520 square feet of netting, Mount Boutmezguida is now the largest fog-harvesting park in the world, and villages across the region have been asking Dar Si Hmad to connect them to fog water.

Today, individuals in homes connected to the fog nets each receive about 18 liters of water a day, a huge jump from the eight liters they were confined to before. Bargach frequently gets requests from other organizations for advice on how to implement their own fog-harvesting parks, and she’s especially excited about the talks she’s had with prospective organizations in Lebanon and Afghanistan. As research into fog harvesting continues, she hopes that people will look into harvesting not only in areas of dense fog like Mount Boutmezguida, but ways to harvest the thin fog that can be found in most regions of the world.

“[It has become] so normalized, opening a tap for water and not thinking about where that is coming from and whether it is sustainable within 10 years or 20 years,” said Bargach. For her, the fog project isn’t just about finding alternatives for water collection. “[It’s about] being in a real relationship with our natural world and not having that separation … a sort of integral and holistic approach to water.”

An earlier version of this article incorrectly calculated the size of WasserStiftung’s fog nets.

These Nets Harness Water From Fog