Evaluating the Role of Urban Drainage Flaws in Triggering Cascading Effects on Critical Infrastructure, Affecting Urban Resilience

The urban drainage system plays an important role in the urban infrastructure resilience discussion. Its functional failures can trigger cascading effects on other urban systems and critical infrastructures. The main aim of this work is to investigate and quantify urban flood resilience, offering an integrated methodological approach. In this process, the flooding consequences were quantified by hydrodynamic simulations, using a case study in an exploratory research method. A set of indicators was proposed to map the cascading effects generated by floods and the consequent quantification of urban flooding resilience. Two simulation scenarios were proposed to validate the methodological assessment framework proposed in this work. The first scenario represented the current flooding situation and showed the negative effects on the city systems resulting from disordered urban growth. The second scenario considered the improvement of the drainage behavior, considering a sustainable urban drainage approach supported by the concept of blue-green infrastructure integrated with the urban open spaces system. A comprehensive flood resilience assessment over time was conducted by analyzing the evolution of the System Integrity Index on both scenarios. The results showed that water dynamics play an important role in ordering land use and that preserving water spaces can efficiently respond to urban developing threats, dealing with floods in an earlier development moment, proving the importance of the drainage system as a preliminary structuring driver for supporting a sustainable urban planning, ordered according to environmental constraints defined by water dynamics.