Rainwater harvesting in Jordan: potential water saving, optimal tank sizing and economic analysis

This paper presents an integrated approach regarding rainwater harvesting that includes investigating potential water savings, optimal tank sizing and cost-benefit analysis at different rainfall zones in Jordan. It is found that a maximum of 30.5 x 10(6) m(3)/year of rainwater can be collected from the roofs of residential buildings which is approximately 8% of the total supply for the year 2015. In addition, water harvesting yields and optimal tank size are calculated for any roof area in different rainfall zones in Jordan. Benefit-cost analyses results revealed that pear shape tanks will be economically feasible in all rainfall zones when a 1 $US/m(3) is assigned as a cost of water saving. Concrete tanks will not be economically feasible at this cost. Payback period analysis indicates that the costs associated with the installation of rainwater harvesting systems could be equalized within 5-45 years depending on the rainfall condition, roof size, price of water savings and tank type.