The study investigates the urban drainage system of Turin, a historically stratified city of about one million inhabitants. Urban drainage networks (UDNs) are key components for stormwater management and flood risk mitigation. Understanding their structural characteristics, both topological and hydraulic, is essential to improve their hydrological response. This study investigates Turin’s UDN through two complementary approaches: (i) identification of scaling laws, inspired by river-basin geomorphology; and (ii) application of weighted and unweighted centrality measures (Betweenness and Closeness) from complex network theory. Results are interpreted through a historical lens, dividing the network into four urban development phases, and a hydraulic lens, assessing the response to two rainfall events. Three scaling laws were identified: Hack’s law ( L ∝ A h ), the scaling between maximum discharge and drained area ( Q ∝ A c ), and the relationship between cross-sectional area and drained area ( S ∝ A p ). Historical development influences the scaling exponents, while longer rainfall events increase c , suggesting links with storage capacity. Betweenness centrality is primarily controlled by topology, whereas closeness is strongly affected by weighting. A significant correlation between closeness ( C ) and maximum flow ( Q ) suggests potential predictive capability. These results highlight the benefit of combining geomorphological and complex network tools for analysing real UDNs, providing a framework applicable to other urban contexts. • Scaling laws characterize hydrological response in a real urban drainage network. • Historical development affects network scaling exponents. • Rainfall duration influences discharge-area scaling. • Betweenness centrality reveals a stable structural backbone of the network. • Weighted closeness correlates with peak discharge, suggesting predictive value.
Eberrini et al. (Thu,) studied this question.