Opportunities in rainwater harvesting

Water scarcity is a major problem in many developing countries. Depending on precipitation intensity rainwater constitutes a potential source of drinking water. In addition, its proper management could reduce water and food crisis in some of these regions. Rainwater harvesting (RWH) is a technology where surface runoff is effectively collected during yielding rain periods. In order to support such technologies RWH systems should be based on local skills, materials and equipment. Harvested rainwater can then be used for rainfed agriculture or water supply for households. Unfortunately, rainwater might be polluted by bacteria and hazardous chemicals requiring treatment before usage. Slow sand filtration and solar technology are methods to reduce the pollution. Membrane technology would also be a potential disinfection technique for a safe drinking water supply.

Rainwater harvesting seems to be a beneficial method for minimizing water scarcity in developing countries. It is essential that local materials and manpower is to be used to spot catchment areas and build up harvesting systems. For agricultural use most of the harvested water can be stored underground in natural systems protecting it from evaporation. On the other hand, rainwater harvested for domestic use may be polluted by bacteria and hazardous substances requiring a vigilant choice of the catchment area. For disinfection purposes there are many techniques available, some of these utilizing natural sources such as solar energy. GIS technology might enhance locating potential areas for RWH.