Methodology of Heritage Impact Assessment for World Heritage nominations: balancing impacts of the new Douro River bridge on Álvaro Siza’s Faculty of Architecture in Porto, Portugal

Abstract Heritage Impact Assessments (HIA) are essential tools for heritage management, balancing potential development plans with heritage safeguarding. This is especially important in what concerns the evaluation of impact on Outstanding Universal Value (OUV) of World Heritage (WH) properties. This paper aims to present how an HIA was adapted to access the possible impacts of the construction of the “New Metro Bridge over the Douro River” in the immediate vicinity of the Faculty of Architecture of the University of Porto (FAUP). This demonstrates an integrated methodology supported on ICOMOS and UNESCO Guidelines, as well as on a cross-cutting analysis of different techniques and tools: documents, interviews, fieldwork and landscape simulations. Hence, this case study provides a valuable pilot reference to be implemented in other case studies, demonstrating HIA as a tool that can be applied in different stages (upstream advice, preliminary assessment, nomination preparation and management planning) of a nomination process, strongly contributing to the credibility and consistency of the WH List.