WHAT YOU NEED TO KNOW
A nonprofit in Peru is gaining attention for its work in developing a simple system that gathers moisture from fog and channels it to storage containers for use in areas where water is in short supply. The systems are dropping in price and increasing in efficiency, experts say. The “fog catchers” have been installed in several countries and were even considered for possible use in the San Francisco area.
At the highest point of Los Tres Miradores, a terrifyingly steep urban settlement with soaring views across Peru’s capital, Lima, there is a curious set of large structures that resemble a fleet of ships in the sky. They are so-called “fog catchers.”
About 40 of these netted devices, made of high-density polyethylene fabric and spanning several meters wide, are lined up atop a misty mound and linked by a network of tubes that lead to storage containers.
Lima is one of the driest cities in the world. It receives less than an inch of rain a year. And that drought is worsening due to climate change. Two million Lima residents do not have access to the municipal water network.
“The water is right under our noses,” says Abel Cruz, whose nonprofit led the initiative to install the fog catchers. “We need it. And we must learn how to take it.”
For Cruz, who grew up in Peru’s mountainous region of Cuzco, this fog represents a massive opportunity. As a boy, he had to hike for more than an hour every day across strenuous hills to collect water from the nearest source. But over time, he realized that during the rainy season, droplets of water would gather in the large leaves of banana trees. One day, he and his father built a canal system with the leaves to collect water.
“We used that water to wash and bathe ourselves and to grow things like tomatoes, lettuce, fruits, plantain,” says Cruz, who moved to Lima at the age of 25.
Shocked by the water shortages and expensive water supply that some of the city’s poorest residents were subjected to, Cruz set up his group in 2005. The idea was to deploy the method he learned in his hometown on a larger, better-adapted scale, which would provide free, independently sourced and easily accessible water to those who needed it the most. He began installing a traditional fog catcher model developed by a pair of Chilean and Canadian researchers in the 1980s.
In June, the project received a significant boost when it signed an agreement with the mayor of Lima to install 10,000 more fog catchers in the next four years. The municipality, which relies heavily on water desalination, said the project has the potential to “reforest, create ecological lungs, ecotourism and at the same time provide water for human consumption, for bio-orchards, botanical gardens, washing clothes, utensils and more.”
In Los Tres Miradores, the 40 fog catchers — which were installed in 2021 — provide enough water for 180 families or to irrigate crops on small garden patches. The nonprofit provided the materials for free, and the community put together the infrastructure themselves.
Gabriel Jaio, 31, lives nearby with his family. Together they use the water to wash clothes and dishes, bathe and cultivate pumpkin, with plans to soon grow carrots and beetroot.
“We need the water, we couldn’t live without it,” says Jaio.
The fog catchers go some way toward addressing the grim inequalities of water supply in Peru. Those outside the service area of the city’s water utility have to pay 10 times more for water that is delivered by trucks.
Proponents believe that fog catchers have the potential to improve water supply for communities around the world amid ever-challenging circumstances. The UN, which has targeted universal access to clean water by 2030, estimates that the global urban population facing water scarcity is projected to rise from 930 million in 2016 to between 1.7 and 2.4 billion in 2050.
German researcher Anne Lummerich says fog catchers “are cheap (and), easy to construct. In a world searching for water supply systems, it is one important puzzle [piece] that can make an essential difference locally.”
There are some issues, however. Fog catchers require space, which is not always easy to come by in cities. And they must be properly cleaned and maintained to stay effective.
Most crucially, appropriate climate conditions are required. Fog isn’t everywhere.
“It’s a very intriguing idea,” says Jay Lund, a professor of civil and environmental engineering and director of the Center for Watershed Sciences at the University of California-Davis. “But for fog catching you need areas with a lot of humidity and temperature change.”
Lund explored the idea of demisting fogs over San Francisco in the aftermath of the droughts in the Bay Area between 2012 and 2016, but concluded it would likely not be economically viable. “In some parts of the world it could be ideal,” says Lund. “But for a modern affluent community you wouldn’t want to do it.”
Yet technological advances could be quickly changing that picture. The fog catchers used in Lima cost about $300 each – down from nearly triple that price a decade ago. And Lummerich says some new designs she is developing can collect up to 2,500 liters of water per day – about 10 times the capacity of those in Lima.
Meanwhile, there are examples of fog catchers working in the Canary Islands and in Africa and Cruz has already helped install hundreds of fog catchers in other Latin American countries. He says that a pilot has even recently been rolled out in Taiwan.
“We have to take fog catchers to the global level,” says Cruz. “We have shown that they work.”
This story was originally published by Reasons To Be Cheerful, a nonprofit editorial project that strives to be a tonic for tumultuous times. It is part of Waterline, an ongoing series exploring the intersection of water, climate and food, told through the eyes of the people impacted by these issues. It is funded by a grant from the Walton Family Foundation.
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