Rainwater harvesting systems for a high quality, supplementary water supply in Nepal

Although Nepal is rich in water resources, in 2011 it was estimated that water supply coverage across Nepal is only 80.4 % of which only 17.9 % of water supply systems are considered to be functioning well. Nepal Water for Health (NEWAH) is a Nepali non-government organisation that has implemented several rainwater harvesting systems (RWHS) in the rural hilly regions of Nepal. Hydrological modelling and analysis of NEWAH’s RWHS allowed for the development of a strategy to improve the effectiveness of the systems. RWHS will always be limited in Nepal due to monsoonal rainfall patterns however this high quality water supply should be prioritised for cooking and drinking. Increasing catchment areas to at least 30 m ² instead of increasing tank volumes can efficiently increase the water supply. A literature review on the quality of harvested rainwater was completed, and recommendations were made for maintaining the high quality of water throughout collection, conveyance, storage and use. Monitoring and evaluation of installed systems is necessary and recommendations need to be further investigated and considered in Nepal where the social and cultural context can be fully understood. Appropriate use of this technology can provide a high quality supplementary water supply that can directly improve the health of consumers and provide those living in the hilly regions of Nepal with the foundations for further development.