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

The assessment of critical infrastructures that are prone to cascade failure phenomena should be addressed from a holistic viewpoint that accounts for the entire cause-effect chain. A characteristic case is the upper dam failure in pumped-storage systems that can significantly affect all 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. This 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. Key question is whether wave heights and run-up at critical locations remain within safety thresholds. By providing insights into the cascading effects of upper dam failures in pumped-storage systems, the proposed framework not only contributes to improved risk assessment methodologies, but also to resilient hydropower design and sustainable water-energy management.