Planning Decision Support System for the Transition to Circular and Green Scaled Urban Water System

Abstract

Climate change and urbanization are intensifying pressures on urban water, energy, food, and ecosystem resources, manifesting in more severe challenges—such as floods and water scarcity—that threaten urban well-being. To address these issues, cities should transition from conventional water management to circular schemes that recover resources and mimic natural processes to restore the water cycle. This study introduces a planning support system using GIS and MCDA to optimize the siting of Water Management Units (WMUs) designed for circularity and greening, integrating supply, wastewater, and stormwater systems. The methodology uses R and QGIS to integrate 15 green infrastructure and 10 circularity criteria. The prioritization framework supports decisions at macro (neighbourhoods) and micro (allotment) scales, promoting equitable resource distribution and maximizing environmental benefits. The case study in Girona, Spain, explores 62 city sectors and 997 allotments to assess context suitability and identify priority sites. Transition scenarios are then analysed to evaluate their impact on the water-energy-food-ecosystem nexus and the social dimension of hydrosocial urban systems. The findings provide actionable insights for urban planners and policymakers, supporting the shift to resilient, circular urban water systems.