Assessment of rooftop rainwater harvesting in northern Jordan

Abstract

Rooftop rainwater harvesting is of high priority for Jordan and drylands because it helps people cope with water shortages during drought conditions. However, there is lack of comprehensive studies that analyze public perception about rooftop rainwater harvesting. The objective of this research is to investigate factors affecting the usage of rooftop rainwater harvesting, quantify the quality of rainwater, and provide preliminary estimate for the volume of rainwater storage tanks and integrate it in the building design. A public questionnaire revealed that 46% of people do not have rooftop rainwater harvesting largely because of the high costs of storage tanks. About 80% of the people surveyed chose an arbitrary volume for the tank based on the recommendation of a building contractor. The current study presented a preliminary estimate for the tank volume using historic monthly rainfall data and various combinations of rooftop area and monthly water demands. The tank storage volumes for all Jordan's northern governorates were then calculated and plotted as contour maps. Laboratory tests on rainwater samples showed that rainwater quality parameters such as TDS, Hardness, and Turbidity were high for the first storms of the rainy season, but decreased progressively afterword. Results obtained from this research suggest that more should be done to encourage the adoption of rooftop rainwater harvesting by decreasing the cost of tank installation and by adopting first-storm flushing systems and integrate that in the building design.