Evaluation of Harvested Rainwater Quality As a Drinking Water Source in Urban Land Uses in Western Province Sri Lanka

Increasing of population around the world has imposed considerable strains on the water resources. Hence, regulatory authorities have faced significant challenges to expand their water supply schemes not only due to financial constraints but also due to limited water resources. Consequently, there has been a growing interest, especially in developing countries, in harvested roof run off as an alternative source of drinking water. However, in determining the end use and the potential success of such an option, the possible problems associated with water quality need to be analyzed and the feasibility of using rainwater as a source of water for household use should be determined. Therefore, this research study was focus on evaluating roof runoff as a drinking water source in different urban land uses where different urban activities are present. For this purpose, a roof runoff samples were collected from three selected land uses namely industrial, commercial and residential. The samples have collected from each land use with three selected roofing materials which are common to the area. This is to evaluate the roof runoff quality based on the variability of land use pattern as well as the variability on roofing materials. All the collected samples have tested for a range of water quality parameters namely, pH, alkalinity, Hardness, Turbidity, TS, COD, Nitrogen (Ammonia), chloride and biological contaminations. Both uni-variate and stacked area analysis techniques were used in the analysis of test results. Based on the outcomes, recommendations are provided to use harvested roof runoff as a drinking water source in urban land uses in Sri Lanka. Keywords urban land uses; drinking water quality parameters; rainwater harvesting