Assessing the feasibility and sustainability of fog water harvesting as an alternative water resource

Iran is experiencing an escalating freshwater crisis due to factors such as population growth, drought, and inadequate water resource management. Atmospheric water, which is six times the volume of all global rivers, presents an untapped potential. This study assesses Iran's potential for fog water harvesting (FWH) by analyzing atmospheric conditions-including relative humidity, fog density, and frequency-along with technical feasibility and a cost-benefit analysis. Data from 120 synoptic stations identified regions with high fog water potential, notably the southern areas, exhibiting yields up to 65 L/m²/day, and northern and eastern regions with potentials between 25 and 45 L/m²/day. Compared to similar global projects, Iran's relative humidity (78%-96%) and the cost of fog water harvesting ($0.25/m³) demonstrate superior feasibility over desalination ($0.6/m³). Additionally, this study highlights the importance of fog type (e.g., advection vs. upslope) and region-specific limitations that may impact implementation. Sustainability considerations-economic, environmental, and social-are addressed, alongside proposed pilot areas such as Kish and Chabahar. Fog water harvesting is positioned as a promising supplement to Iran's national water strategy.