A Review on Rainwater Harvesting in Sri Lanka

Freshwater scarcity is one of the emerging threats to human survival. There is a gap between availability and demand for freshwater due to urbanization, industrialization, overpopulation, contamination of groundwater, and unpredictable climatic conditions. Rainwater harvesting is an environmentally sound option to mitigate the water scarcity issue. Further, rainwater is a sustainable water source that can be utilized to satisfy the water demand considerably. This manuscript reviews the rainwater harvesting systems in Sri Lanka with particular emphasis on history and present status, different techniques and methods, climate change adaptation, quality and treatments, utilization of harvested water, health benefits and issues, and policy and strategies in the Sri Lankan context. Rainwater harvesting is not a new technology in Sri Lanka; it was even practiced by ancient Sri Lankans many centuries ago. Anyhow, special attention to the operation and maintenance of the rainwater harvesting systems should be paid to improve the quality of harvested water for further uses. In addition, the effectiveness of the policies related to rainwater harvesting should be ensured for the better functioning of rainwater harvesting systems all around the country.