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The Atacama Desert in Chile is one of the driest places on Earth; average rainfall is less than 0.1 millimeters per year. However, water does exist in this harsh climate, it's just rather difficult to catch.
A coastal fog, called "camanchaca" by the locals, is blown inland and coats the desert in a mysterious, white haze. Unfortunately, the water droplets that form in these delicate clouds aren't heavy enough to fall to the ground as rain.
While the water is frustratingly close but impossible for humans to use, some of nature's creatures have overcome this problem—for example, a tiny, unassuming beetle that lives in southern Africa's arid Namib Desert. The Namib beetle (Stenocara gracilipes) has a specially designed shell with bumps on it that attract and catch water droplets from the morning fog that rolls in. Grooves in the beetle's shell then channel the water to the its mouth for a tasty morning drink.
Taking inspiration from the beetle, Shreerang Chhatre of the Massachusetts Institute of Technology (MIT) developed a mesh with water-attracting and catching properties. Water clings to the surface of the mesh but doesn't absorb into the fabric, which would be wasteful. The net's surface also repels water so that the droplets can roll off the surface and subsequently be funneled into a storage tank located at the bottom of the net. The idea of netting fog isn't new, but Chhatre has been working on the efficacy of fog harvesters.
Carlos Espinosa Arancibia, a now-retired physics professor, has been testing the fog-catching nets in Chile's driest regions. His nets have tiny openings of about one millimeter, which water sticks to and subsequently accumulates around. When the drop eventually becomes heavy enough, it runs down the net into the collection tank. The nets themselves are cheap and durable: An average-sized fog catcher of 40 square meters (430 square feet) costs between $1,000 (£635) and $1,500 (£965) depending on the material used. It is a sustainable and cheap alternative to installing water pipes and pumping water into remote regions.
So far, the largest number of nets installed are in Tojquia, Guatemala, where 60 fog nets catch 4,000 liters of water a day.
Either by chance or through genius forethought, one of Espinosa's test sites is near the town of Pena Blanca, which is home to a local brewery. The brewery has been using the fog-captured water to make 24,000 liters of beer per year.
But it's not just brewers that are benefiting from the fog nets. When the nets were placed in areas the desert was expanding into, Espinosa said he was able to prevent the desertification of nearly a square kilometer of land, helping sustain local plant life in the process.
Top Image Credit: Danielle Pereira, Flickr CC by 2.0
