Evaluation of Rainwater Harvesting Systems in Three Major cities of New South Wales

Abstract

Rainwater harvesting (RWH) systems are becoming more popular to reduce pressure on mains water as well as to serve as a sole freshwater supply system in rural areas. Australia is a large continent with highly variable rainfall and hence performance of a RWH system varies from location to location. This paper presents reliability and water-saving potential of a RWH system in three major cities namely Sydney, Newcastle and Wollongong of New South Wales (NSW) State of Australia. A python-based daily water balance model is built to analyse the performance of a RWH system, which uses rainfall, loss, water demand and roof catchment data. To enable selection of ideal rainwater tank size for the selected locations, three different water uses (toilet and laundry, irrigation, and combined use) and five tank sizes (1, 5, 10, 20 and 30 kL) are considered. It is found that the rainwater tank size is influenced by roof area, number of users, water demand and rainfall characteristics. This study will help in decision-making regarding implementation of a RWH system in these Australian cities. This research also contributes towards achieving water related sustainable development goals (SDG).