Modelling soil detachment by overland flow for the soil in the Tibet Plateau of China

Abstract

The overland flow erosion is common and became more serious because of the climate warming inducing more runoff in the Tibet Plateau. The purposes of this study were to evaluate the effects of flow rate, slope gradient, shear stress, stream power, unit stream power and unit energy of water-carrying section on the soil detachment capacity for the soil in the Tibet Plateau of China due to the information is limited. To achieve this aim, laboratory experiments were performed under six flow rates (5, 10, 15, 20, 25 and 30 L min −1 ) and six slope gradients (8.74%, 17.63%, 26.79%, 36.40%, 46.63 and 57.73%) by using a slope-adjustable steel hydraulic flume (4 m length, 0.4 m width, 0.2 m depth). The results indicated that soil detachment capacity ranged from 0.173 to 6.325 kg m −2 s −1 with 1.972 kg m −2 s −1 on average. The soil detachment capacity increased with power function as the flow rate and the slope gradient augmented (R 2 = 0.965, NRMSE = 0.177 and NSE = 0.954). The soil detachment capacity was more influenced by flow rate than by slope gradient in this study. The relation between soil detachment capacity and shear stress, stream power, unit stream power and unit energy of water-carrying section can be described by using the linear function and power function, the power function relationship performed better than the linear function in generally. The stream power exhibits the best performance in describing the soil detachment capacity among shear stress, stream power, unit stream power and unit energy of water-carrying section in this study. The erodibility value in this study was larger than and the critical shear stress was less than those for soil in the eastern China. There has a huge potential for the soil in the Tibet Plateau eroded by the water erosion when enough runoff exiting. More attention should be payed to the water erosion process and mechanism in the Tibet Plateau area in the future.

Formation of stable aggregates by fluid-assembled solid bridges

“…It is possible that the formation and strength of soil aggregates has more to do with size than with material composition. The wetting behavior of soils is of fundamental importance for soil collapse (47,48), creep and liquefaction in landslides (28,49), and slaking erosion that results from disintegration of aggregates (27,29). Modeling frameworks consider only granular friction, fluid drag, and pore pressure effects.…”

“…In the natural environment, soil cohesion determines the erosion susceptibility of landscapes, including riverbanks, marshes, hillsides, and agricultural fields (25)(26)(27). Cohesion is an important factor in geotechnical applications (28,29), and a crucial parameter in transport of contaminants and microorganisms in the environment (30,31). Many natural and industrial materials are composed of particles of various size, shape, and surface charge, and are subject to intermittent cycles of wetting and drying.…”

Effect of Freeze-Thaw Cycles on Soil Detachment Capacities of Three Loamy Soils on the Loess Plateau of China

“…Obviously, soil properties in this experiment proved to be the most important factor that significantly influenced soil detachment capacity, determined by soil types and the number of freeze-thaw cycles. The process of soil detachment in the Qinghai-Tibet plateau was significantly lower than that of other regions of China, which was related to the degree of freeze-thaw and soil properties, but the specific mechanism of the effect was unclear [49].…”

The Influence Mechanism of Freeze-Thaw on Soil Erosion: A Review

“…Different from the Loess Plateau, the permafrost in the Qinghai-Tibet Plateau was relatively thick, which required long-term field location monitoring and large scale indoor simulation tests for mutual verification [37]. Li et al [38] found that the erosion resistance of the Qinghai-Tibet Plateau was significantly lower than that of other regions, which was related to the degree of freeze-thaw and soil properties, but the specific influencing mechanism remained unclear.…”