Abstract: Indoor artificial rainfall experiment was conducted to address the soil and water loss of deposit slopes caused by the construction of power transmission projects in typical red soil region. Three rainfall intensities (2, 2.5 and 3 mm/min) and two slope gradients (10°and 15°) were designed in the experiment. The relationships between rainfall intensity, slope gradient, sediment yield characteristics and rill erosion features (density, fragmentation, tortuosity complexity, and width-depth ratio) were analyzed. Results manifest that under different rainfall intensities, both sediment yield and infiltration rate on the red soil deposit slope decreased with the increasing of rainfall duration, while runoff yield increased with the elongation of rainfall. The density, fragmentation, tortuosity complexity, and width-depth ratio were 0.77-1.35 m/m², 0.04-0.08, 0.91-1.40, and 1.01-2.39, respectively, among which the width-depth ratio reduced with the increase of rainfall intensity and slope gradient, whereas the former three parameters exhibited the opposite trend. The erosion rate was mostly correlated with the tortuosity complexity of rill, and less correlated with the fragmentation, density, and width-depth ratio of rill in sequence. The research findings provide technical parameters and a basis for preventing soil erosion in red soil areas induced by the construction of power transmission projects.

Key words: rill erosion, power transmission projects, engineering deposits, simulated rainfall, runoff and sediment yield