Fog Nets: Harvesting Water from the Air

In some parts of the world, rain is unreliable, but fog is common. In these places, a simple technology pulls drinking water directly out of the air. Fog nets are made of fine mesh stretched across a sturdy frame. They are placed in the path of the wind that blows most often in an area. As fog drifts through the mesh, tiny water droplets in the air hit the fine fibers and stick to them. These droplets gradually build into larger drops. The drops run down into a collection trough below and flow by gravity into a storage tank. The largest working example of this technology is in Morocco's Anti-Atlas mountains. There, a German engineer designed a net loosely modeled on how a spider's web collects dew. His three-dimensional mesh replaced older, less effective flat mesh panels. A Moroccan nonprofit organization installs and maintains the network of nets near Mount Boutmezguida. The nets collect thousands of liters of water on an average day. This water is piped directly to households in several nearby Berber villages through prepaid meters. This spares residents, most of them women, the long daily walk once needed to fetch water by hand. The system needs no electricity and has no moving parts. It can also withstand strong mountain winds. Because of this, it has proven very durable since installation. It offers a low-maintenance water source in a region where normal infrastructure is difficult and expensive to build.