Impacts of rainfall intensity and slope gradient on rill erosion processes at loessial hillslope

•Impacts of rainfall intensity and slope gradient on rill erosion were investigated.•Rill erosion rate and critical runoff rate per unit width equations were generated.•Mean headward erosion rates varied between 2.2 and 8.2cmmin−1.•Hillslope rill erosion was sensitive to rill flow velocity and stream power.