Analysis of the Erosion and Deposition Process and its Influencing Factors in the Lower Watercourse in the Estuary of the Yellow River

During1964–2012 the estuarial reach of Yellow River underwent three avulsions, which brought significant changes in the erosion/deposition in the lower Yellow River. The initial stage of each avulsion included a decrease in the length of the lower watercourse in the estuary of the Yellow River and an increase in the gradient in the estuarine watercourse, which affected erosion and deposition in the lower watercourse of the Yellow River. To distinguish the extent of the effects of various factors on the evolution of the lower watercourse of the Yellow River, the correlations between discharge, sediment concentration and incoming sediment coefficient and erosion and deposition in the lower watercourse of the Yellow River were analyzed. The results show there was a weak correlation between erosion and deposition in the lower watercourse of the Yellow River and the water and sediment process. This suggests that changes in the water and sediment process were not the principal factor affecting erosion and deposition in the lower watercourse of the Yellow River. Instead, the occurrence of frequent avulsions in the lower watercourse of the Yellow River is the principal factor affecting erosion and deposition. At the initial stage of each avulsion of the flow path, there is a significant decrease in the flow rate in the lower watercourse of the Yellow River, resulting in the deposition of a significant amount of sediment. The closer the avulsion point is to the upstream region, the greater the change in the length of the flow path after the avulsion and the greater the impact of the avulsion on erosion and deposition in the watercourse.