Improvement of urban water metabolism at the district level for a Mediterranean compact city

Cities are under constant and increasing pressure because of global changes, fast urbanization and growing resources demand. Those threats force urban systems to find development opportunities and solutions to minimize the demand and to shift from linear to circular economy, in which recycling and reusing are key activities [1]. Urban Metabolism (UM) analysis has become an important tool for the study of urban ecosystems. The problems of large metabolic throughput, low metabolic efficiency and disordered metabolic processes are a major cause of unhealthy urban systems. Nowadays, the most critical urban resource flow is water, followed by energy and materials: water is vital for our survival and the largest component in terms of sheer mass [2]. Furthermore, climate change increases geohydrological risks (landslides, floods and sinkholes), especially in Italy, causing damages and threats to the population, requiring a better management of the water cycle. However, due to the complexity of contemporary urban phenomena, it is difficult to understand what happens within those urban systems and to answer to these current pressures. Applying the UM at the city level presents some limitations due to the lack of data and the generalizations required at this scale. The traditional approach considers the city as a “black box”, quantifying in-flows and out-flows. Indeed, resources availability depends strongly on local context characteristics that enable the reduction of input water flows, maximizing the reuse of wastewaters and closing water loops. Along with the new challenges of sustainable design, it is possible to define different scenarios and roadmaps for compact cities, developing decision support systems that follows the principles of urban metabolism at the local scale. This research presents a project to evaluate the local water potential in a portion of the compact city of Rome in order to improve the local metabolism through a more efficient use of the resource. The innovative methodology will enable sustainable actions through the identification and assessment of a set of green projects to suggest pathways that enhance the modification of water metabolic flows.