Measuring urban water circularity: Development and implementation of a Water Circularity Indicator

Urban Water Management (UWM) involves balancing the inflows and outflows of water such that water enter-ing and leaving the system boundary reduces with time. Several frameworks and indicators have been formu-lated for UWM with a limited focus to achieve circularity of water flows at all the phases of the engineered urban water cycle. A novel indicator called 'Water Circularity Indicator' (WCI) is developed in this study to assess, monitor and improve the circularity of urban water flows. The WCI is derived from Material Circularity Indicator developed by Ellen McArthur Foundation and Granta design. In the current study, WCI is initially validated using 100 scenarios considering the variation of 5Rs, i.e., reduce, reuse, recycle, reclaim and restore. Further, WCI is compared with other indicators focusing on urban water management from the literature. The evaluation of re-sults indicate that WCI correlates with most of the indicators selected for comparison. The WCI uses the water mass balance principle in its derivation and distinctively captures reuse, recycling, reclamation and restoration strategies in a single indicator value compared to other indicators. The WCI provides maximum information in a single indicator value ranging from 0 to 1.0. A higher value of WCI indicates lesser extraction of virgin water re-sources and wastewater disposal with maximum water circulation within the city under consideration. The nov-elty of WCI lies in its unique approach of considering all 5Rs and easy interpretation for decision-makers across multiple domains. WCI is recommended to be used by city authorities and policy makers for achieving water goals and for Circular Economy (CE) implementation. Policies can be formulated based on WCI to enhance CE in the water sector and reduce virgin water consumption, ultimately leading to water conservation.(c) 2022 Institution of Chemical Engineers. Published by Elsevier Ltd. All rights reserved.