Fog Harvesting Requirements

According to Dr Anthony Turton, an environmental advisor and water specialist, fog harvesting sites must be at least 1,000 metres above sea level and receive a minimum of 90 days of fog precipitation per year. The water content of the fog should be high, and the fog must be accompanied by wind to ensure that a large enough volume of moist air is blown through the collecting screens. The downside of such a project is that it yields relatively small amounts of water, which, depending on the area, may have to be treated as a result of contamination. The equipment needed, however, is simple and requires little maintenance. A netting structure is erected between two poles and placed perpendicular to the prevailing wind. Wind blows the low mist cloud into the nets where the water is intercepted. The water droplets gather here until they overcome gravity and slowly trickle into a gutter attached to the bottom of the net. A simple sand filter removes solid impurities, and the water is then channelled via pipes to water containers close by. Turton, however, cautions that we cannot fog harvest the volume of water we will need in South Africa. “Instead we need to change our citizens from water consumers into water stewards. Greater emphasis needs to be placed on educating children about water, and the country in general about respecting our wetlands, which play a critical role in keeping river systems healthy.”Agrifood_SDE