Influence of hydraulic properties on soil detachment rate at different slope positions during the spring thaw period

Abstract

Rainfall and snowmelt runoff are the primary drivers of soil detachment in cold regions. Understanding how hydraulic properties influence the soil detachment rate (D_r) is essential for accurately modelling soil erosion during the spring thaw period. This study aimed to clarify the relationship between hydraulic parameters and D_r at different slope positions. Experiments were conducted under four flow discharge conditions (4.5, 6.5, 8.5 and 10.5 L min⁻¹), two slope gradients (10° and 15°) and four thawing depths (2, 5, 10 and 15 cm). Results indicated Dr could be adequately described as a power function of the flow discharges increasing with shear stress, the resistance coefficient and stream power. Shear stress was identified as the most effective hydrodynamic parameter for predicting D_r at upslope (first slope) and midslope (second slope) positions, whereas stream power best predicted D_r at the downslope (third slope) position. Unit stream power was not a reliable predictor of D_r. These findings enhance the mechanistic understanding of soil erosion processes occurring during the spring thaw period and improve the predictive capabilities of soil erosion models.