Fog water as an alternative and sustainable water resource

As the world's population and demand for fresh water increases, new water resources are needed. One commonly overlooked aspect of the water cycle is fog, which is an important part of the hydrology of coastal, high-altitude, and forested regions. Fog water harvesting is being investigated as a sustainable alternative water resource for drinking water and reforestation. Fog water harvesting involves using mesh nets to collect water as fog passes through them. The materials of these nets, along with environmental factors such as wind speed, influence the volume of water collected. In this article, a review of current models for fog collection, designs, and applications of fog water harvesting is provided. Aspects of fog water harvesting requiring further research and development are identified. In regions with frequent fog events, fog water harvesting is a sustainable drinking water resource for rural communities with low per capita water usage. However, an analysis of fog water harvesting potential for the coastal areas of northern California (USA) showed that fog yields are too small for use as domestic water in areas with higher household water demands. Fog water shows particular promise for application in reforestation. Fog water irrigation can increase growth rates and survivability of saplings in reforestation efforts in regions with frequent fog events. Using fog collectors, denuded areas once dependent on natural fog drip can be restored, benefiting local hydrology and ecosystem recovery. Improvement in fog collector designs, materials, and models to increase collection efficiency, perhaps by inclusion of ideas from natural systems, will expand the regions where fog harvesting can be applied.