Integrated methodology for environmental-urban diagnosis and prioritization of drainage interventions to enhance urban flood resilience

Rapid global urbanization has intensified challenges related to unplanned growth, inefficient land use, and increased flood risk. Flood impacts, exacerbated by urban densification and land-use change, currently threaten approximately 1.81 billion people worldwide, affecting infrastructure, ecosystems, and human lives. This context highlights the need to integrate urban and environmental planning through sustainable approaches. Nature-based solutions and blue-green infrastructure offer strong potential to enhance urban flood resilience by combining ecological and hydraulic functions, while delivering co-benefits such as biodiversity enhancement, microclimate regulation, and improved urban livability. Aligning urban development with natural processes is particularly critical in vulnerable areas where conventional drainage systems are under pressure. In response, this study proposes an integrated environmental-urban diagnostic methodology that defines objective functions, identifies priority intervention areas, clarifies the role of each drainage project, and enables the measurement and comparison of intervention efficiency for flood risk reduction. Designed to be quantitative, accessible, and adaptable, the framework bridges scientific knowledge and municipal decision-making. The methodology was tested in Maricá (Rio de Janeiro, Brazil), focusing on the Bambu River basin, demonstrating its effectiveness in supporting integrated, resilient, and sustainable urban flood management.