Effects of initial water content on hillslope rainfall infiltration and soil water redistribution

Under preventing soil erosion and controlling evaporation after rainfall, the effects of initial water content on hillslope rainfall infiltration, wetting front movement and soil water redistribution were studied with simulated rainfall. The results show that when initial water content is higher, runoff generation is earlier, average infiltration rate is smaller, and the time to be stable infiltration rate is shorter. Rainfall infiltration into a planar hillslope with homogeneous isotropic soil could be simply regarded as one-dimensional infiltration process, and wetting front is nearly parallel to the soil surface and moves down vertically during rainfall infiltration and soil water redistribution, when the distribution of initial water content is uniform. Wetting front moves faster with higher initial water content during soil water redistribution, but its movement depends on the wetted degree and scope of soil during rainfall infiltration, when the distribution of initial water content is non-uniform. Runoff from upslope has little effect on wetting front movement but helps to increase infiltration. Moreover, soil water would move downslope after rainfall infiltration was terminative.