Researchers in Chile are launching a project to combat water scarcity in the Atacama Desert by setting up fog collectors in and around Alto Hospicio. These fog collectors will be used in practical experiments and computer models to calculate the potential of supplying the city with water. This initiative aims to test the viability of fog harvesting as a sustainable water source for urban environments, particularly in rapidly growing cities facing severe water shortages.
Alto Hospicio, situated at an altitude of 500 meters, has experienced rapid growth to approximately 110,000 inhabitants. Of the many residents living in unregistered areas lacking infrastructure only 1.6 percent are connected to the water network. As a result, most inhabitants depend on water deliveries by truck, and the poorest residents often have no direct access to clean water networks.
The Atacama Desert in Chile is considered one of the driest regions in the world, receiving less than five millimeters of rainfall per year. Fog is a regular phenomenon in Alto Hospicio from May to October, forming over the Pacific Ocean when warm, moist air currents pass over cold water and then traveling towards the mountains. As these moisture-laden clouds pass through, they offer a crucial potential water source that has been overlooked so far.
Fog harvesting involves using fine mesh nets as interception surfaces to catch moisture from passing fog clouds. The droplets of moisture collected on the mesh panels flow into a trough and are channeled into storage tanks without the need for external energy, making fog collection a passive and energy-efficient system. This method can yield several liters of water per square meter daily, providing a sustainable source of drinking water for some of the world's driest cities.
Dr. Virginia Carter Gamberini of Universidad Mayor, who is leading the study, believes that fog harvesting could serve as a complementary urban water supply in dry lands where climate change exacerbates water scarcity. "Collecting water from unconventional sources like fog offers a valuable way to improve quality of life," she said, according to BioBioChile. Gamberini added that while fog nets do not solve all challenges with clean water, "it is a start."
The research team calculates that, based on an average water collection rate of 2.5 liters per square meter per day, a net area of 17,000 square meters would be sufficient to provide 300,000 liters of water weekly for the urban slums of Alto Hospicio, which is currently delivered by truck to locals in the area. According to ORF Science, this amount of water could alleviate the reliance on trucked water deliveries and improve access to clean water for thousands of residents.
For fog harvesting to be effective, optimal geographic and atmospheric conditions are required, including fog density, suitable wind patterns, and well-oriented elevated landforms. Seasonal variability in fog also needs to be accounted for.
Moreover, large storage systems, good piping networks, and well-thought-out ways of distributing the water would be necessary to utilize the collected fog water effectively and transport it to where it is most urgently needed. The implementation of such infrastructure is essential for the success of fog harvesting projects in urban settings.
While fog harvesting holds potential, the research team cautions that it should not be targeted as the sole solution to water scarcity. Instead, it must be integrated into a more comprehensive water strategy. This approach could enhance urban resilience to climate change and rapid urbanization while improving access to clean water.
In addition to providing drinking water, the collected fog water could be used for irrigating green spaces and local food production. Fog water could support soil-free hydroponic agriculture in Alto Hospicio, producing between 15 and 20 kilograms of green vegetables per month. This would contribute to food security and improve the overall quality of life in the community.
The concept of fog harvesting is not entirely new. It has been used on a small scale in some rural areas of South America and Africa with suitable conditions for fog. However, Gamberini's research represents a shift in the perception of fog water use—from a rural, rather small-scale solution to a practical water resource for cities.
Local researchers, including Gamberini and her colleagues, are also preparing a "fog water harvesting map" across Chile, which will show data for all locations where fog collectors could potentially contribute to providing clean water. This map will be released in May and accessible to both private companies and local governments.
The challenges faced by Alto Hospicio are indicative of broader issues in arid regions where climate change exacerbates water scarcity. Many Chilean cities rely on groundwater sourced from aquifers that were last replenished 10,000 to 17,000 years ago. BBC News points out that these aquifers are now drying up due to increased urban population and industrial use.
The article was written with the assistance of a news analysis system.