This study explores the application of MPM in designing runout protection berms for debris flows, avalanches, fast-moving landslides, and mining structure failures. The analysis integrates both 2D and 3D simulations using Anura3D to provide a comprehensive understanding of debris flow dynamics and berm performance. In contrast to earlier studies of debris flow impacts on rigid structures, this work explored the benefits of a flexible berm that can deform or move to absorb debris flow energy. 2D run-out simulations were performed using data from a historical mining structure failure event to calibrate the model's contact friction coefficient between the debris and foundation. The simulations employed a one-phase single-point formulation with dry materials. This stage produced velocity-distance curves that characterize the behaviour of the debris flow as a function of run-out distance. Additional simulations included a 10 m-high berm located 600 m downstream from the initial debris front. Following the runout analysis, a parametric study was conducted to assess the effects of varying debris mass and impact velocities on berm performance. The retention berm was analysed for its ability to deform, displace relative to the foundation, and roll upon impact, capturing different energy dissipation mechanisms. The simulation results were compared with the runout analysis to identify the optimal berm height and location. A 3D analysis was performed to simulate the impact of a debris flow with limited width, providing a deeper understanding of how lateral confinement influences berm stability. This analysis revealed that the lateral constraints provided by the berm geometry enhance its resistance to debris flow impacts. The findings from the simulations informed the design of a protection berm, providing specific recommendations for its height and location to ensure optimal performance. The study demonstrates the potential of MPM, as implemented in Anura3D, as an effective tool for designing runout protection berms.