A new model for long-term global water demand projection

Abstract

Rational projection of water demand is critically important to the future development of society. Achieving the desired accuracy for long-term water demand projection (WDP) is challenging due to the complex and uncertain relationships between water demand and various socio-economic indicators. At the same time, traditional forecasting methods, such as multivariate statistical analysis and time series analysis methods, are not adequate for long-term WDP because of the limitations in modelling structures. In this study, a five-staged WDP model is proposed and applied to the global WDPs. The hypothesis for the new model is that water demand is related to socio-economic development level. From the historic data in the Western Europe and United States, the five stages of water demand can be clearly observed. These stages are marked by evident change in water demand trend, and are categorized by the per capita GDP at that stage. The proposed WDP model is then validated with historic water consumption data in United Kingdom and Hong Kong, and the proposed model can explain the historic water consumption well. The developed five-staged WDP model is applied to the WDPs in Hong Kong and Pearl River Basin. Further, using the newly developed water consumption algorithm, this study investigates the global future water demand.