Quantitative Assessment of Future Sustainability Performance in Urban Water Services using WaterMet²

Abstract

Urban water services are likely to face challenges in the future, mainly due to population growth, climate change, increasing urbanization and ageing infrastructure. These factors are expected to impose significant strains on the performance of urban water services. This would subsequently decrease the capacity and quality of services in the urban water system (UWS) and thus negatively affect different dimensions of the sustainability framework (i.e. economic, environmental, social, asset and governance) presented by Alegre et al. (2012). Performance of future sustainability in the UWS can be evaluated by using simulation of metabolism-based processes in the urban water cycles over a pre-specified horizon. The WaterMet² model developed in the TRUST project quantifies the metabolism-based performance of the integrated UWS. The integrated modelling of the UWS implies the whole processes and components in an urban area related to water flows as a complex and interrelated system. A mass balance approach of water is followed within the system. WaterMet² enables the calculation of quantitative key performance indicators (KPI) of urban water services over a long-term planning horizon. These KPIs encompass various aspects of water systems sustainability such as cost (economic), GHG emissions (environmental), water supply reliability (social) and leakage (assets). WaterMet² can support various intervention strategies by calculating the relevant quantitative KPIs which can be used for a multi-criteria decision analysis in a decision support system framework. The overall KPI values (calculated on a per-capita basis) obtained from the UWS can be used for comparing sustainability indicators of water services among different cities. The comparison of KPI values in the main UWS components reveals the critical components for which appropriate intervention options should be undertaken.