Construction analysis of rainwater harvesting systems

We present the results of a simulation to assess the optimal design characteristics of rainwater harvesting systems to be used in a semi-arid region of the United States. The simulation leverages a stochastic, non-parametric rainfall generator based on 64-years of daily historical data. The assumption of non-stationarity of rainfall is also thoroughly investigated for this paper. Of specific interest to this simulation was the estimate of roof capture space and cistern capacity required for a 100% reliable system capable of supporting family sizes of two or three for a 30-year time horizon. Considerations included rainfall supply, system capture efficiency, household occupancy, as well as individual demand variation. The optimal design characteristics in terms of roof surface area and cistern volume necessary for 100% reliability are presented using two response surface plots and separate multiple regression modeling based on expected occupancy.