Rainwater Harvesting Systems in Metropolitan Area Using Probabilistic Approaches

The efficiencies of rainwater harvesting systems (RHS) are often affected by temporal distribution of rainfall and water demand. Since natural precipitation is a random process and will have probabilistic characteristics, it is necessary to describe these probabilistic features of rainfall and its relationship with the design storage capacity as well as the supply deficit of the RHS. This paper aim at developing a methodology for establishing the probabilistic relationship between rainfall and the storage capacity of RHS. A simulation model was build to simulate the input rainfall and water release in the RHS. Historical rainfall records were then used as input for simulation and the results were used in probabilistic analysis for establishing the relationship between storage capacity and water supply deficits. The city of Taipei was used as the study area for the demonstration of this methodology.