Potential Impulse Wave Analysis for Sejiang Deforming Slope on the Near-Dam Reservoir Bank of Bala Hydropower Station of China

Landslide-generated impulse waves in deeply incised gorge regions pose significant risks to hydropower infrastructure, particularly under fluctuating reservoir water levels. This study investigates the potential global instability sliding of the Sejiang deforming slope on the left bank of the Bala Hydropower Station, Sichuan Province of China. A three-dimensional numerical simulation of the landslide–water entry, wave generation, and propagation processes conducted using computational fluid dynamics (CFD) shows a maximum wave height of 5.57 m on the opposite bank. Moreover, the CFD results were compared with those derived from Pan′s empirical formula method. In contrast, Pan′s empirical formula only provides conservative predictions for water-entry velocity and wave height, with a maximum wave height of 13.60 m on the opposite bank. Notably, the CFD numerical simulations precisely characterize complex topographic effects, such as the approximately 156% wave height amplification at the spoil disposal bend due to reflection and superposition, as well as the localized energy convergence in front of the dam. Furthermore, the impulse wave destructive potential is positively correlated with reservoir water levels. While the assessment confirms no risk of dam overtopping under the current scenarios, it highlights the necessity for differentiated protection strategies targeting three critical zones, i.e., the initial wave impact zone, the multi-directional superposition zone at the spoil disposal area, and the localized energy convergence zone near the dam. This study provides a reliable quantitative basis for refined hazard assessment and disaster mitigation in complex reservoir topographies.