Erosion resistance and scouring depth of fine-grained seabed of the Huanghe River estuary, China

Abstract

Numerical calculation is an effective method to predict the scouring depth of fine-grained sediments. However, as many soil properties affect sediment erodibility, numerically simulated parameters, such as critical erosion stress τ c , may result in wrong prediction. To understand the erosion resistance and scouring depth of fine-grained seabed in the Huanghe (Yellow) River estuary, China, the authors calculated the critical erosion stress τ c of the bottom sediments using regression equations that correlated physical properties to critical shear stress of silty fine-grained sediment of the research area and predicted the scouring depth of the study area using different available formulae. The results indicate that τ c ranges from 0.48 to 1.74 Pa. Comparisons show that the results calculated from the empirical formula proposed by Kandiah are close to the measured data, and choosing the right parameters of sediment in the formula decides the accuracy of the scouring depth calculation. With the Kandiah τ c value, the seabed scouring amplitudes in wave action periods of 5, 10, 25 and 50 years were simulated. The calculated results of scouring depth are between 0 and 0.23 m and the corresponding scouring center was predicted to be in the region of depths between 5 and 9 m. Meanwhile, the scouring center was found to be highly correlated with wave breaking and sediment properties.