Fog collection as a source of fresh water supply in the Kingdom of Saudi Arabia

In order to harvest water contained in fog, the topographical features and the climatic conditions of 27 cities in the Kingdom of Saudi Arabia were studied. The topography, altitude and orientation are some of the factors that determined the selection of the site. It was identified that the southwest of the region in the kingdom was the most suitable location for the fog-collection process. In order to evaluate the effectiveness of fog water collection and the site, three identical standard fog collectors (SFCs) with two different local collection materials were designed and manufactured. Experiments were conducted at two different locations in the area close to Abha, namely Soodha. The maximum amount of water collected was 22.9 L/m(2) in a day and 7.25 L/m(2) in a 2-h period. It was found that there was a high probability of fog when the relative humidity was higher than 95%. The results from the chemical analyses of eight sets of fog water samples collected were compared with World Health Organization drinking water standards. It was found that the level of heavy metals was negligible and the level of Fe was marginally high for the first flush only. The study indicates that in terms of both quality and magnitude of yield, fog is a viable source of water and can be successfully used to supplement water supplies in the fog-prone regions of the kingdom.