Modeling the sediment transport capacity on non-erodible frozen soil slope of overland flow

Abstract

Seasonal soil erosion is a common occurrence in severe cold regions. It is critical to establish the relationship between the sediment transport capacity of a frozen soil slope and its influencing factors. Thus, in this study, a scouring experiment with eight slope gradients (1.5°, 3°, 4.5°, 6°, 7.5°, 9°, 10.5°, and 12°) and six flow discharges (0.15, 0.25, 0.35, 0.45, 0.55, and 0.65 L s−1), was carried out to explore the effects of slope gradient and flow discharge on sediment transport capacity. Then, based on the experiment, sediment transport models were established and verified to quantify the relationships between sediment transport capacity and water erosion factors of overland flow on frozen soil. The results showed that sediment transport capacity increased with increasing slope gradient and flow discharge as a power function (R2 = 0.983, NSE = 0.970). The sensitivity of flow discharge to sediment transport capacity was more than that of the slope gradient on a non-erodible frozen soil slope. Sediment transport capacity increased in power by increasing the mean flow velocity (R2 = 0.918, NSE = 0.890). The mean flow velocity was the best hydrodynamic parameter for predicting the sediment transport capacity among stream power (R2 = 0.894, NSE = 0.911), shear stress (R2 = 0.823, NSE = 0.818), and unit stream power (R2 = 0.643, NSE = 0.537). In conclusion, the result of this research is helpful in measuring the sediment transport capacity of non-erodible frozen soil slopes and in investigating the sediment transport process of frozen soil in cold regions.