Harnessing Fog for Water: A Sustainable Solution for Arid Cities

Scientific studies in Alto Hospicio, Chile, demonstrate the viability of large-scale fog harvesting to provide essential drinking water to its urban slums, potentially benefiting both residents and agriculture.

Capturing water from fog is emerging as a promising method to address water shortages faced by arid cities, according to recent research conducted in Chile. The research led by Dr. Virginia Carter Gamberini of Universidad Mayor focused on Alto Hospicio, a desert city enduring less than 0.19 inches (5 mm) of rainfall annually and grappling with a host of socio-economic challenges, including poverty and inadequate access to clean drinking water.

In communities where access to conventional water supplies is limited, residents rely on truck deliveries for their drinking water. However, researchers emphasize that the regular formation of fog over the coastal mountains is a previously untapped resource ripe for harvesting. The fog harvesting technique involves hanging mesh panels that capture moisture-laden clouds, allowing droplets to collect and flow into storage tanks.

While fog harvesting has been practiced on a small scale in certain regions of South and Central America for decades, Dr. Carter advocates for a new wave of large-scale fog harvesting initiatives in urban settings where water scarcity is acute. To ascertain the water-harvesting potential, Dr. Carter's team assessed fog volumes and cloud formations using satellite imagery and weather forecasts, revealing that the Pacific-origin fog enveloping Alto Hospicio could offer a sustainable drinking water source for its inhabitants.

Their findings, published in the journal Frontiers of Environmental Science, highlight that a mesh area of just 17,000 square meters could yield enough water to satisfy the weekly demand of 300,000 liters, which is currently met by truck deliveries. Moreover, 110 square meters of mesh could fulfill the annual irrigation needs for the city's green spaces, while also enabling hydroponically grown crops.

The study underscores that water sourced from fog can not only meet immediate demands but also bolster urban resilience against climate change impacts. Given that Alto Hospicio lies adjacent to the Atacama Desert—one of the planet's driest regions with dwindling aquifers—Dr. Carter notes the critical need for sustainable water alternatives as urban populations continue to rise.

Her team is now embarking on a comprehensive mapping of fog harvesting potential across Chile, aiming to implement solutions that enhance access to clean water while fostering agricultural innovation. As Dr. Carter suggests, this "water from the clouds" initiative could play a vital role in creating sustainable communities in an age of climate uncertainty.