Potential Rainwater Harvesting: An Adaptation Measure for Urban Areas in Jordan

This study investigated the potential of harvesting rainwater from the roofs of nonresidential buildings in populated urban areas in Amman, Jordan, using geographic information system (GIS) techniques. Amman has a mean annual rainfall of 378 mm, which makes rainwater harvesting viable and feasible. The rainfall data recorded at seven different weather stations were processed statistically to produce reliable averaging surface and isohyetal maps for rainfall over Amman. The GIS layer was generated for roofs and catchments to identify the suitable rainwater harvesting sites. Results show that the potential water collected by rainwater harvesting is five times less expensive than that collected via the conventional water supply system. The net total water savings by rainwater harvesting is 3.45 × 106 m3/year, and this could reduce the nonrevenue water and other losses by ∼1%. Furthermore, rainwater harvesting has a potential positive environmental impact by reducing CO2 emissions by about 6.57 tons.