Dam Heightening as a Climate Adaptation Strategy in the Italian Alps

The increasing frequency and severity of droughts in southern Europe are placing growing pressures on interconnected water-energy-food-environment systems. In Alpine regions, climate change is intensifying hydrological variability through declining snowpack and glacier storage and by altering runoff seasonality, thereby widening the temporal mismatch between water availability and multisectoral demands. In this context, the expansion of existing water storage capacity is emerging as a potential adaptation strategy to buffer hydrological variability and mitigate drought impacts.This study assesses the synergies and trade-offs of expanding water storage in the Italian Alps through dam heightening. We first apply a multi-criteria evaluation framework to screen and prioritize alternative dam heightening projects. The multisector impacts of the selected alternatives are subsequently evaluated using a distributed hydrological model that explicitly integrates reservoir operations and water transfers related to hydropower operations. Our results demonstrate that dam heightening can substantially improve drought resilience in the region by reducing the gap between water availability and demand under current and projected climate conditions. Overall, this work provides a transferable and policy-relevant framework to support climate-resilient water infrastructure planning in Alpine systems under increasing drought risk.