Measuring sediment transport capacity in ephemeral gully through adjustment of sediment feeding

Abstract Sediment transport capacity (STC) is an important parameter for quantifying the erosion process in ephemeral gully. It is not practical to build a flume long enough to measure the STC in ephemeral gully through traditional soil erosion. Therefore, a methodology and a criteria were proposed to adjust the sediment feeding by regulating the length of main sediment supply section to achieve measurement of STC in ephemeral gully. The STC measurements were conducted under slope gradients of 5°, 10°, 15°, and 20° and unit-width flow rates of 5.33, 10.67, 21.33 and 42.67 m3 s−1 m−1. The measured STC in ephemeral gullies ranged from 1.19 to 38.29 kg s−1 m−1 with high accuracy. Also, the measured STCs were positively and well correlated with unit-width flow rate and slope gradient. According to the values of Reynolds number and Froude number, the water flow in experimental ephemeral gully can be categorized as a turbulent and supercritical flow. A multivariate non-linear model was developed to predict the STC with slope gradients and unit-width flow rates, which performed well under experimental hydraulic conditions. The proposed methodology and measuring setup provide a new and reliable approach for measuring STC in ephemeral gully.