Steel baffle installed on footing is commonly used to resist and dissipate the impact energy from boulders carried by debris flow. However, the deformation of a baffle and the resulting energy transfer to the footing during the impact process compound the challenges of predicting the impact force and size of the footing required. In this study, full-scale experiments were conducted to simulate a boulder impacting a steel baffle installed on a square footing. The experimental data were back-analyzed using a three-dimensional (3D) finite element model, which was then used to conduct a parametric study to examine the effects of a range of impact energies and footing sizes. New design charts are developed to assess the required size of a square footing, embedded up to 2 m depth, for a steel baffle subjected to boulder impact with energy in the range of 10–100 kJ. [ABSTRACT FROM AUTHOR]