269 / 2024-02-28 21:06:54

Research on the Impact of Downstream Sandy Riverbed Erosion and Incision on the Diversion at Songzi Kou

Three Gorges Project, Songzi Kou, Sediment Diversion and Distribution, Fixed-Bed, Physical Model

The Songzi River serves as a critical diversion channel in the Jingjiang Reach, being the foremost among the "Three Outlets in Jingnan." Alterations in its diversion patterns significantly influence flood control, water resource utilization, shipping, and the water environment and ecology of the Songzi River System. This study employs a fixed-bed physical model test to investigate the impact of downstream sandy riverbed erosion and incision on the diversion at Songzi Kou. The findings reveal that when the water level at Yangjianao, Zhicheng station, decreases by 2 and 3 meters with a flow rate of 6000m³/s, the diversion flow at Songzi Kou diminishes by 5 and 10m³/s, respectively, representing 10% and 20% of the current diversion flow. Similarly, a drop in the water level at Yangjianao by 1 and 2 meters with a flow rate of 30000m³/s leads to a reduction in diversion flow at Songzi Kou by 180 and 270m³/s, accounting for 5.4% and 8.1% of the current diversion flow, respectively. Notably, a more significant decrease in the water level of Yangjianao at Zhicheng station, under the same flow conditions, leads to a more pronounced reduction in the dry river water level near Songzi Kou, thus resulting in a larger decrease in the diversion flow. Similarly, an increase in flow at Zhicheng station causes a more substantial drop in the dry river water level near Songzi Kou, given the same reduction in the water level of Yangjianao, further amplifying the reduction in the diversion flow.