Effects of Wind Speed on the Characteristics of Rill Erosion on Windward Slope Under Rainfall Conditions

Abstract

[Objective] This study was aimed to elucidate wind-induced rill erosion characteristics on the windward slope. [Methods] Artificial simulated wind-driven rain experiments were conducted. The study investigated changes in water and sediment processes as well as rill morphology under different wind speed conditions (0, 3, 5, and 7 m/s). [Results] Compared to slopes without wind, the windward slope exhibited a 20.59%~47.06% increase in flow generation time and a 33.10%~137.78% increase in the occurrence of falling ridges. The average slope flow velocity decreased by 12.86%~22.53%. Runoff and sediment production rates notably decreased with increasing wind speed (p < 0.05). The runoff production rate on windward slopes followed a similar trend under different wind speeds, gradually increasing with rainfall before stabilizing over time, with no significant differences observed among stages at different wind speeds. Sediment yield rates increased rapidly with prolonged rainfall duration, followed by a gradual decrease and stabilization. Nodes of sediment yield rate changes aligned closely with the occurrence of falling ridges. Rill dimensions (width, depth, fluctuation degree) decreased with rising wind speed. The width-depth ratio and rill inclination ranged from 1.40 to 1.69 and 13.47 to 14.76 degrees, respectively, increasing with higher wind speeds. Under various wind speed conditions, rill volume, splitting degree, and density ranged from 4.39 to 10.27 cm3, 0.024 to 0.042, and 2.03 to 2.92 m/m2, respectively, all decreasing with increasing wind speed. [Conclusion] The volume, density and degree of fragmentation of rills are all significantly positively correlated with the amount of slope erosion, making them the preferred indicators for characterizing the morphology of rills on windward slopes.

Keywords

• rill erosion
• wind speed
• windward slope
• rill morphology