Abstract: To address the challenges of energy dissipation and scour prevention downstream of the sediment flushing gate at the Peruvian San Gabán Ⅲ Hydropower Station, this study integrates the unique hydrogeological conditions of the headwork area of project and employs a combined approach of theoretical calculations and physical model experiments to conduct an in-depth research on the energy dissipation and scour prevention design scheme downstream of the San Gabán Ⅲ hydropower station sediment flushing gate. The results demonstrate that the adoption of rib-roughening and a layered, partitioned protection scheme effectively resolves scour issues caused by high-velocity flow in steep-slope river channels. The research outcomes provide valuable references and practical insights for similar engineering projects.