Application of hydroinformatic tools to assess flood flow conditions under a medieval masonry arch bridge

Medieval arch bridges are important heritage that requires a continuous effort for their preservation. Hydrodynamic actions during flood events have to be properly assessed in order to evaluate their safety status. However, behind the structural aspects, the characterization of their interference in the river flow during extreme events constitutes a challenge task. This paper discusses the hydraulic aspects of a comprehensive study that is being developed to study a medieval masonry arch bridge over Cávado River at the city of Barcelos, Portugal. A set of models were implemented involving different spatial scales in order to characterize different river hydrodynamic scenarios including floods and normal regimes to be considered during the planned restoration work. A river basin model was implemented in Sobek software to propagate flood hydrographs from the upstream reservoir until the bridge river section. A two-dimensional hydrodynamic model was implemented to simulate the bridge river area using Delft3dFM software. Finally, a 3D model was set-up in FLOW-3D software to analyze the loads of the river flow over the masonry bridge. Details of the methodology used in the modelling approaches are presented together with simulated results. These results will be analyzed together with the observed consequences for the bridge structure damages that are precious testimonials of the intensity associated with historical flood events