Everything old is new again. Even water.
Fog harvesting, a technique used by nature and ancient civilizations to wring water out of the air, is getting a second look as modern technology tackles an age-old problem. Drought-parched communities around the world are running out of options. As water tables drop, populations grow, and the climate changes, having sustainable sources of water in relatively arid regions has taken on new urgency.
Fog harvesting, used by beetles and redwoods alike, is a chance to pour fresh, clean water into empty cisterns.
The technology works by creating surfaces where tiny airborne water droplets condense on a surface. These flow into the ground or waiting vessels. Redwoods on the Pacific Coast use pine needles, while West African beetles have specially evolved shells that attract water droplets then channel rivulets toward their mouth.
For humans, the answer is mesh (we covered how MIT is borrowing the beetles’ technology for its own design). Huge nets are hung in the air where foggy air currents pass, usually ocean breezes. The mesh captures water droplets that are redirected to water livestock, plants, and supply drinking water. Fog harvesters can capture one liter of water per one square meter of mesh, with recorded yields as high as five liters in parts of Africa.
Now, the research is getting more serious, with organizations such as the nonprofit FogQuest dedicated to fog and rain harvesting in rural areas. It has set up projects in Guatemala, Ethiopia, Nepal, Eritrea, and Chile, where the first first large-scale applications of this technique were built in the late 1980s.
But the technology is still in the experimental stage. The environmental effects are not fully understood, and the best way to be build these nets has not been settled. One of the next research sites will be the Moroccan town of Sidi Ifni, where residents spend hours to visit a local well, while seasonal droughts force many of the villages’ men and livestock to move elsewhere. Little has been reported on how these systems work in practice: Reporter Lindsey Hoshaw plans to visit Sidi Ifni for a story in The New York Times if sponsored through the journalism crowdsourcing site, Spot.Us, to gauge the technology’s chance of success.
The coming decades should see plenty of researchers exploring ways fog harvesting can free communities from the vagaries of drought.