**1. Introduction**

Floods are among the most widespread climate-related [1] and frequently occurring natural hazards. In the past decade alone, the annual reported economic losses from floods have reached tens of billions of US dollars, with their repercussions affecting thousands of people. More specifically, historic city centers and heritage buildings are particularly vulnerable to the destruction caused by flooding. This can be attributed to the fact that ancient settlements tend to be located within the vicinities of water sources, attesting to the important role water plays in the development of

these communities. Unfortunately, this also means that the locations of present-day heritage structures and buildings are primarily within flood-prone areas, giving them a preexisting disadvantage of being exposed to hazardous conditions.

All these reasons demonstrate the necessity to develop further studies and methods to understand and manage the flood risk, especially for historic sites and structures. They have the propensity to present certain singularities, such as construction typologies and traditional building materials, that can lead to an increase in their vulnerability to flooding hazards. The potential loss of buildings with high and irreplaceable cultural value, as well as the consequent economic impacts from which a city could suffer, stresses the urgency to develop systems of indicators for managing the risk to heritage assets. These systems aim to provide valuable information for the assessment of the impact of natural hazards on cultural, social, economic, and environmental conditions. As such, historic centers are critical areas of study and deserve special attention.

To this end, the present study discusses the application of a recently developed flood risk-assessment approach that combines flood hazard and building vulnerability indicators to identify and classify risk while also defining intervention priorities. This methodology [1] is implemented in the Historic City Center of Aveiro, Portugal, particularly in the Beira Mar neighborhood, one of the most picturesque of the city. Due to its proximity to the Ria de Aveiro and the system of canals throughout the historic center, the city is highly prone to flooding. The selection of Aveiro's historic center as the subject of this large-scale risk assessment is further supported by the city's unique history and architecture, widely recognized to be of high heritage value and significance.

This study involves the survey and evaluation of 495 buildings, completed on-site as well as through remote survey methods, which are usually the go-to methods for the vulnerability assessment of post-earthquake events [2–5]. The results were integrated into a Geographic Information System (GIS) tool, alongside prepared flood hazard data, for subsequent analysis of the respective flood vulnerability and risk. Through this macro-scale risk assessment, it is hopeful that valuable insight is generated into the manner in which each building is affected by the flood events. Discussions also include proposals of effective risk management and mitigation strategies, comparison of results with an existing case study, as well as adaptions of the methodology for utilization in different contexts.
