Cascading impacts of individual failures across critical infrastructures: The case of upper dam breach in pumped-storage hydropower schemes

The assessment of critical infrastructures vulnerable to cascade failure phenomena requires a holistic viewpoint accounting for the full cause-effect chain. A key case is the upper dam failure in pumped-storage hydropower (PSH) systems, which can severely impact downstream infrastructures. This study proposes a generalized framework to examine the potential consequences of this catastrophic event, which is then showcased to a planned pumped-storage system in the Aliakmon River basin, Greece. It integrates hydrodynamic simulations and semi-empirical approaches to assess dam failure mechanisms and flood wave propagation, impulse wave generation, flood routing through the lower reservoir, and resulting risks. Several scenarios are deployed through HEC-RAS and BASEbreach models, accounting for the influence of terrain on wave dynamics and flood propagation. Impulse waves generated by sudden water inflows are modeled using theoretical and semi-empirical methods, with key parameters such as wave amplitude, run-up, and attenuation evaluated under both 2D and 3D propagation conditions. The core scientific question is whether wave heights and run-up remain within safety thresholds, and how resilient PSH systems are under cascading failures. The framework supports enhanced risk assessment, resilient hydropower design, and sustainable water-energy infrastructure planning.