Assessing the potential of rooftop rainwater harvesting in a rapidly urbanizing suburb -

Abstract

The Hazmieh-Hadath-Baabda area is a rapidly urbanizing Beirut suburb suffering from chronic water shortages. This research examined the current sources of water supplying the area through a household survey and assessed the socioeconomic feasibility of using rainwater harvesting systems on rooftops. A water quality assessment program was carried out in parallel whereby samples from network water, municipal water, well water and rainwater were tested for specific quality indicators. Findings revealed that the quality of network and municipal water supplied to households largely conformed to the Ministry of Environment standards and World Health Organization guidelines. The major problem faced in the area was the deficit between the available supply and actual demand. In the face of chronic shortages, households in the area expressed interest in participating in rainwater harvesting programs. Examining the socio-economic factors affecting the willingness of people to participate in a RWHS, it was found that education and the availability of outdoor space affected the rate of participation positively, while age and the number of floors in a building decreased people’s keenness to participate. The results revealed that on average, a household with a monthly income $1500 was willing to pay $ 0.54 -m³ to install a RWHS as compared to $ 2.34-m³ for those whose monthly income is more than $6000. A technical assessment of the feasibility of a rainwater harvesting system (RWHS) revealed that while it is advantageous for a single household with 5 occupants, the harvested volumes for a multistory residential building (50 occupants) were small as compared to demands. The study concludes with a management framework that aims to assure the proper implementation and monitoring of rainwater harvesting practices.