Action research study on rain water harvesting

Many areas in Sri Lanka offer a good potential for the introduction of rain water harvesting; however, as many people do not appreciate this method as a source of domestic and drinking water, the technology is undervalued. This report is the result of a feasibility study on rain water harvesting in Sri Lanka seeking to formulate a policy for the Community Water Supply and Sanitation Project to enhance the application of rain water harvesting methods. The study was comprised of four main steps: design and construction of trial storage tanks, visits to existing rain water harvesting places in Sri Lanka, field visits to selected pilot project villages, and the collection and analysis of rainfall data (maps, tables, and graphs included). In rain water harvesting, reliability of the supply depends on the size of the catchment area - often the roof -, the volume of the storage tank, and the management of the daily consumption, all in relation to the local rainfall pattern. The study attempts to develop a suitable technical and economical solution to the storage of drinking water, and as a result, proposes brick dome and ferrocement as the two most cost-effective options. Quality of rain water in storage is addressed on the basis of a literature study. Recommendations are given in respect of further trials and field monitoring. Promotion and awareness raising for greater appreciation of rain water harvesting is advocated.