Prediction of sediment transport capacity using thawed depth deduced from temperature measurement

Abstract

In cold regions, changes in thawed soil depth induced by temperature fluctuation are commonly observed and can affect sediment transport capacity of meltwater flow and erosion processes. In this paper, a method based on laboratory experiment was proposed to predict sediment transport capacity using the thawed soil depth derived from temperature at different soil depths measured during the experimental time period. A saturated soil column with platinum resistance sensors at depths of 5, 10, 15, 20, and 25 cm from the soil surface was placed in a freezer at -25, -20, and -15 °C until it was totally frozen and then placed in an incubator with a constant temperature of 25, 30, and 35 °C. The thawing processes of the frozen soil column were monitored by the sensors that measured temperature during the experimental time. Based on soil heat conduction mechanism, the relations among soil depth, temperature, and time were deduced as a function to predict thawed soil depth giving the frozen temperature, soil temperature inside the incubator, and time after being placed in the incubator. The sediment transport capacity was then calculated by combining the deduced thawed soil depth function and an existing model. The predicted sediment transport capacity was compared with laboratory measurements in literatures. The results show that the model has the ability of predicting sediment transport capacity ranged from 0.019 to 0.598 kg s−1 m−1 with high R2 of 0.99 and 0.98. It suggests that the proposed model can be used to predict the sediment transport capacity by concentrated meltwater flow on different thawed soil slope. This research contributes to our understanding of soil erosion processes by meltwater on partially thawed soil slope.