Integrated assessment of the societal welfare benefits of flood adaptation under different climate change scenarios: Evidence from northeastern Italy

Alpine regions in Europe are increasingly affected by short-duration, high-intensity precipitation events, leading to localised floods and flash floods that generate severe and spatially uneven impacts. In these contexts, where settlements, economic activities and critical infrastructure are often concentrated in narrow valley areas, such events pose growing challenges for regional adaptation planning. Moreover, climate change is expected to exacerbate both the frequency and intensity of convective precipitation extremes, amplifying flood-related risks in territories already characterised by complex topography and limited capacity to absorb hydrological shocks, partly due to high land-use pressures. Most flood risk assessments have traditionally focused on hazard exposure and physical vulnerability, often neglecting the welfare dimension of climate impacts. As a consequence, they provide limited guidance for comparing adaptation options in terms of their societal benefits. Based on these premises, this study firstly provides an integrated assessment of flood risk and adaptation benefits that combines high-resolution hydroclimatic impact modelling with stated preference valuation of avoided damages. Drawing on a case study in northeastern Italy, we quantified both the evolution of flood exposure under two future climate time horizons (2041–2050 and 2090–2099) and the economic value that residents assign to reducing flood impacts across five land-use domains: residential areas, productive areas, road infrastructure, agricultural land, and tourism-related facilities. The hydroclimatic impact modelling reveals a progressive intensification of flood exposure across all land-use domains. End-of-century projections indicate particularly severe impacts in mountainous zones, where the flooded surface reaching up to 21% for road infrastructure and 25% for agricultural land. The stated-preference valuation, based on a discrete choice experiment administered to a representative sample of 2,000 residents, shows that individuals assign the highest marginal economic value to the protection of residential areas, followed by productive areas, agricultural land and roads. Tourism-related facilities receive the lowest valuation, indicating that not all exposed domains are perceived as equally critical from a societal welfare perspective. Combining physical projections with economic evidence, we derived population-level estimates of the societal benefits of flood impact reduction. The resulting welfare indicators offer a transparent benchmark for evaluating the societal desirability of alternative adaptation strategies. We derived a monetary threshold against which the cost of an adaptation measure can be compared to determine whether the investment is socially justified. This study is the first integration of hazard modelling and stated preference valuation. Our findings enhance the operational relevance of climate risk assessment and supports the design of adaptation strategies that reflect both physical exposure and socially perceived value. It also provides insights to inform evidence-based climate governance in regions facing intensifying hydroclimatic risk.