Investigation of the potential of fogwater harvesting in the Western Mountainous parts of the Yemen

The Republic of Yemen is located in an arid to semi-arid region. Rainfall rates range from none at certain parts of the country to about 400 mm/yr in its mountainous parts. Rainfall has been harvested and collected in cisterns existed in the mountainous region for generations. In the dry season (October-February) and after the stored water is consumed, people mainly women and children have to travel long distances down wadis to fetch water from the nearest water source which is often not suitable for human consumption. This is the case in the western mountainous region, namely Hajja Governorate, which heavily depends on rain water for drinking, animal watering, domestic uses and irrigation. However, during the dry season this region experiences foggy conditions. This has prompted conducting a fog collection field study in this region to investigate the potential of providing an alternative source for water supply during the dry season. The study consisted of installing 26 standard fog collectors (SFC) of one m2 of polypropylene mesh at 19 sites in Hajja and measuring the daily fog water amounts collected during the period from 1 January to 31 March, 2003. The results indicated that fog collectors located closest to the red sea with an elevation ranged between 2000-2200 meters above sea level and winds from the west direction have produced the highest water output, reaching a maximum of about 4.5 liters per square meter of mesh per day over the three winter months period. The conclusion drawn is that though this technique is cheap, simple and promising, more investigations are still needed on the various parameters contributing to fog collection, such as, relative humidity, temperature and SFCs technologies. (author)