Flood vulnerability and risk assessment of historic urban areas: Vulnerability evaluation, derivation of depth‐damage curves and cost–benefit analysis of flood adaptation measures applied to the historic city centre of Tomar, Portugal

Abstract

Around 45% of natural hazards reported worldwide are related to floods, and current indications show that exposure to floods and inherent losses will keep escalating. Historic centres are particularly vulnerable in this context due to the structural and material characteristics of the buildings and because they embrace social and cultural values that must be safeguarded. This article aims to contribute to this research area by presenting and discussing the application of an index-based methodology specifically tailored to assess flood risk in historic urban centres. The historic city centre of Tomar, Portugal, an area that encompasses over 500 buildings and has a rich history of floods, is used here as a case study. Vulnerability data resulting from the application of the vulnerability assessment approach are then combined with flood hazard-that is, water velocity and depth obtained from flood peaks estimated for 20-and 100-year periods of return-and used to identify the buildings at risk. Finally, a set of depth-damage curves is derived and used here to carry out a costbenefit analysis for different flood adaptation measures.exposure, flood risk, historic urban centres, sensitivity, vulnerability assessment | INTRODUCTIONEvery year the world faces many climate-related and geophysical hazards. And although low-income countries tend to be particularly affected by those hazards due to poor infrastructure systems, disastrous floods in countries like Pakistan, Puerto Rico, the United States, and the United Kingdom prove that floods are a global threat (Rentschler et al., 2022). In Europe alone, reported economic losses due to disasters amount to 281 billion US$, of which 52% are due to floods. It is estimated that exposure to floods, and consequently damage losses, will grow

Preparing for severe flooding: Flood risk management research leading to better flood preparedness

“…New approaches are also being continually applied and developed to help identify flood‐vulnerable areas. Davis et al (2023) applied an index‐based method to identify buildings at risk to flooding in vulnerable historic urban centres and examined a cost–benefit approach for implementation of flood adaptation measures. Machine learning techniques, applied by Vojtek et al (2023), evaluate riverine flood potential and identify areas at the highest risk of riverine flooding.…”