Preserving the past in a changing climate: an approach to assess the impact of urban flooding in cultural heritage cities

Urban floods are increasing due to the intensification of precipitation extremes in a changing climate and to the intensive expansion of urbanscapes. Therefore, flood hazards can potentially increase losses to historical buildings and cultural heritage. In this context, this study proposes a methodology to assess the impact of climate change on urban flooding at the district and building scale. The methodology is applied in the Santa Croce District, where an extensive collection of masterpieces of the city of Florence (Italy) is preserved and exposed, especially in the National Central Library. The flood hazard assessment is obtained by using a dual drainage hydraulic model to quantify the flooded area within the buildings due to the overflow of sewer systems. An ensemble of 34 climate model projections based on output from Phase 6 of the Climate Model Intercomparison Project (CMIP6) in two emission scenarios, or Shared Socioeconomic Pathways (SSP245 and SSP585) and two time windows (2021–2050, Near Future, and 2071–2100, Far Future) are considered as input of the model. The results show that the flood hazard will increase in all climate scenarios, especially in the SSP585 at the end of the century.