Modeling non-residential urban water use: Case Study on two high water use schools in Melbourne

Modeling urban water use plays a key role in water resource planning and management. The urban water use consists of both residential and non-residential water use. As observed from the literature, a vast amount of research has been conducted on modeling residential water use. However, a significant portion (e.g. around 30% of total water use in Melbourne, Australia) of urban water use belongs to non-residential sector, and limited attention has been given to modeling non-residential urban water use. Therefore, this project aims to model non-residential urban water use. The method adopted was first to disaggregate water use based on the heterogeneous nature of water use customers (e.g. schools, hospitals and restaurants) and their annual water usage (e.g. >20ML, 15-20ML, 10-15ML, etc.), and then to develop multiple linear regression models for each user group. Two high water use schools in Melbourne, Australia were considered as case studies. The model was developed using independent variables of past water use, season and water restrictions. Quarterly billing data for the five years of 2005-2009 was used in this study to develop separate models for two schools. The models were calibrated using four years data from 2005 to 2008 and showed very good results with the coefficient of determination (R²) values of 0.93 and 0.96. The models were then validated using 2009 observed data, and again showed strong correlation with R² values of 0.87 and 0.89. Furthermore, the mean absolute error (MAE) and the root mean square error (RMSE) for both calibration and validation were low. These results show that the developed models have good capability of modeling water use of the two schools considered in this study.