A framework for urban planning structured by sustainable urban drainage: the proposal of a priority matrix for site selection

Urbanization transforms landscapes, increasing urban flooding risk due to changes in the water cycle. Urban planning should incorporate blue and green infrastructure (BGI) to integrate flood mitigation strategies within the landscape under a multifunctional approach. This work aims to develop, apply, and evaluate supportive tools to guide urban planning actions focused on effective urban drainage choices in a sustainable and resilient manner. An original multicriteria tool, named the Priority Matrix, combines gravity, urgency, and tendency assessments to define focal areas for drainage interventions. The index is applied to a selected watershed, leading to a critical analysis that generates guidelines for urban projects and identifies focal points for urban design. A multifunctional urban design intervention combining grey, blue, and green infrastructure was proposed for the site to achieve flood mitigation. The project was evaluated using a hydrological-hydrodynamic simulation tool, confirming the index's purpose and efficiency in selecting critical sites and informing discussions about local challenges. The evaluation demonstrated success in flood mitigation, illustrating the potential for creating multifunctional landscapes that incorporate social and ecological functions into effective urban drainage projects.