A new study published in the Frontiers in Environmental Science journal suggests that ‘fog harvesting’ a process where the water vapour in fog is collected and saved, could alleviate water shortages in some of the driest regions of the world.
The researchers explored the potential of fog harvesting as a water source in Alto Hospicio, a municipality in Chile’s Atacama Desert that receives less than 1mm of rainfall annually, instead sourcing its water from underground reserves.
To conduct the fog harvesting, a mesh is suspended between two posts to capture moisture from the air. Water droplets accumulate on the mesh and fall into a gutter that directs the water into storage tanks, a process that requires no external energy.
A practical resource
“This research represents a notable shift in the perception of fog water use—from a rural, rather small-scale solution to a practical water resource for cities,” commented Dr Virginia Carter Gamberini, an assistant professor at Universidad Mayor and co-author of the study. “Our findings demonstrate that fog can serve as a complementary urban water supply in drylands where climate change exacerbates water shortages.”
Alto Hospicio has a rapidly growing population, with approximately 10,000 people living in informal settlements, many of whom are not connected to municipal water distribution networks and rely on water deliveries by truck.
The year-long study suggested that in a 100 square kilometre area around Alto Hospicio, between 0.2 and 5 litres of fog water could be harvested per square meter each day, largely at higher altitudes.
During the study’s peak season, August and September of 2024, collection potential reached up to 10 litres per square metre a day.
“By showcasing its potential in Alto Hospicio, one of Chile’s most stigmatised yet rapidly urbanising cities, this study lays the groundwork for broader adoption in other water-scarce urban areas,” said Nathalie Verbrugghe, a researcher at Université libre de Bruxelles and a co-author of the study.
Weekly water demand
According to the study, approximately 17,000 square meters of mesh could produce enough water to meet the weekly water demand for the poorer communities in Alto Hospicio, while also being used for irrigation and local food production.
For the study to be replicated in other parts of the world, they add, the geographic and atmospheric conditions need to be just right.
“Key prerequisites include fog density, suitable wind patterns, and well-oriented elevated landforms. Additionally, since fog is seasonal in many regions, this variability should be considered,” Verbrugghe added. Read more here.
