Rainwater harvesting in North Africa: A novel method for reservoir sizing

In North Africa water is becoming a scarce resource, fragile and unevenly distributed across different areas. Because ofeconomic and human growth considerations, water demand is continuously increasing. Johns Hopkins University, USA,states that in 2025 the annual quantity of water per person in Algeria will be less than 500 m3; hence the need to seek newresources to substitute or complement existing ones. Unconventional resources are positioned well as possible solutions.These include groundwater recharge, desalination of seawater, water recycling, reuse of treated wastewater, and rainwaterharvesting. Rainwater harvesting is an old method used almost anywhere in the world. The main drawback of this methodis the calculation of the reservoir volume, which is approximate at best. This article presents a novel approach for theestimation of required reservoir volume as a function of roof surface area, number of household inhabitants, and rainfalldistribution