Surface stones affect erosion rates by reducing raindrop-driven detachment and protecting the original soil against overland flow induced-hydraulic stress. The aims of this study were, (i) to quantify how the stone characteristics affect the total sediment concentration and the concentrations of the individual size classes, (ii) to test if stones affect preferentially a particular size class within the eroded sediment and (iii) to determine whether the 1D Hairsine-Rose (H-R) erosion model can represent the experimental data. To achieve these goals, experiments were conducted at (i) the 2-m × 6-m EPFL erosion flume, different rainfall intensities (28 and 74 mm h-1) and with a gentle slope (2.2%), (ii) for different initial conditions, and (iii) with two stones coverage proportions (20 and 40%).