三峡工程蓄水运用后太子矶河段右岸扁担洲附近河床近期冲刷明显,局部崩岸严重时将威胁堤防安全、影响附近河势控制节点和下游汊道分流比的变化及右汊东港主槽航道条件的稳定性。多年实测资料揭示了该河段近期河床演变特点及其变化趋势。结果表明:多年来岸线基本稳定;深泓线除长河口-幸福村顺直段变化较大外,其余河段变化较小;-5、-10、-15 m等高线深槽略有冲刷;铁铜洲汊道将继续维持左支右主的河势格局,右汊总体呈冲刷趋势;扁担洲附近局部河段河床累积冲刷明显。提出亟需对扁担洲局部冲刷严重段进行抛石防护,加强水文和险工段动态监测和跟踪分析等相关中长期防治措施建议,可为新水沙条件下该河段未来河道治理方案研究提供重要的技术支撑。

[Objective] Significant recent scouring of the riverbed has been observed near Biandanzhou on the right bank of the Taiziji Reach, potentially threatening dike safety, influencing river regime control nodes, and altering the flow distribution ratio of downstream branches. Meanwhile, the navigation conditions in the main channel of Donggang on the right branch remain unstable. [Methods] To ensure flood control and navigation safety, this study analyzed the recent riverbed evolution of the Taiziji Reach based on the latest original underwater topographic observation data and long-term measured records. The study also predicted river regime development trends and proposed corresponding preventive and control measures to address existing issues. [Results] The shoreline has remained generally stable over the years. Except for the straight reach from Changhekou to Xingfucun, the thalweg has shown limited variation. The most significant platform migration, with a maximum lateral migration of approximately 1.1 km, was recorded in the Biandanzhou-Xingfucun area. The thalweg elevation generally exhibited a lower upstream and higher downstream pattern, with alternating changes in elevation over time. The -5,-10, and -15 m contour lines showed a slight overall scouring trend in the deep channel. The Tietongzhou branch would continue to exhibit a pattern of left branch and right main channel, with the right branch showing a general scouring trend. Locally, severe scouring near Biandanzhou was evident inter-annually, with the right bank retreating by approximately 700 m between 1981 and 2021 and the maximum local depth of scouring in the riverbed about 12 m. [Conclusions] It is recommended to implement protective measures as soon as possible for the severely scoured sections near Biandanzhou. Continuous enhancement of hydrological and topographic monitoring and follow-up analyses is essential. Once issues are identified, engineering interventions such as river regulation works should be promptly adopted. The results of this study provide critical technical support for future river management strategies in the Taiziji Reach under new flow-sediment conditions.