Rainwater Harvesting in a Southern California City

This paper presents a case study of rainwater harvesting potential in a small residential city located in the semi-arid Southern California through implementation of low impact development (LID) devices. To model the rainwater capture potential, a storm water management model of the existing storm system is developed using PCSWMM, a modeling platform based on the EPA SWMM model. The model looks at the effect of the 2-year and 10-year 24-hour design storm under 3 different scenarios considering–(1) a single rain barrel, (2) five rain barrels, and (3) a storage tank in each residential lot. Results show that using either a single or five rain barrels captures a relatively small amount of rainwater. However, a storage tank per lot increases the city’s rainwater capture efficiency and from a single storm the city can collect more than 3.5% of its annual reclaimed water volume.