Formal Methods in Flood Disaster Response: The Case of Porto Alegre, Brazil

This paper provides an account of the formal methods used to inform and examine the performance of Porto Alegre’s Metropolitan Region road-circulation network after the May 2024 floods. Comparisons between the pre-disaster configuration and three post-disaster scenarios are made, using configurational analysis, highlighting how the urban grid cohesiveness was affected by the inundations, both at a local and at a regional scale. Key findings showcase important overall system performance shifts in terms of relative accessibility and preferential routes’ choice, especially concerning vehicular movement. Results also indicate that local movement patterns tended to be preserved, despite the floods dimension, which aided to maintain the internal cohesiveness of the network. Furthermore, the paper also demonstrates how those formal methods were incorporated into pilot decision-support actions, co-designed through the engagement with local authorities, to provide the early-responders and decision-makers on the field with information about the network viability changes, useful to identify priorities in de-obstruction and which road-elements were to be preserved to avoid a larger system collapse.