Sediment Scouring and Silting Threshold in the Middle and Lower Reaches of the Yangtze River Before and After the Three Gorges Project
Year: 2025
Type: article
Abstract: Understanding sediment transport under varying flow regimes and its associated scouring–silting responses is fundamental for analyzing the coupled dynamics of hydrology and river morphology. However, in large alluvial rivers strongly modified by human interventions such as dam operations, identifying critical thresholds of scouring–silting transitions remains a major challenge. This study examines sediment transport dynamics and flow frequency patterns through statistical analysis and the coefficient of determination method, using daily discharge and suspended sediment concentration records from eight hydrological stations along the middle and lower Yangtze River, China, covering 1990–2023. The results demonstrate that the impoundment of the Three Gorges Reservoir substantially altered downstream hydrological and sediment regimes, leading to a more uniform flow frequency distribution, suppression of extreme flows, and increased prevalence of moderate discharges. These adjustments stabilized river flows and improved sediment transport efficiency. Distinct spatial variations were identified across seven river sections: upstream reaches shifted from bimodal scouring–silting patterns to scouring-dominated regimes, whereas downstream reaches exhibited weakened sediment deposition. Moreover, critical thresholds of both flow and sediment coefficients displayed systematic longitudinal shifts. Collectively, these findings provide new insights into water–sediment interactions under large-scale regulation and offer practical implications for sediment management in highly engineered river systems.
Source: Sustainability
DOI: 10.3390/su17219606
Language: English
Subfield: Ecology
Field: Environmental Science
Domain: Physical Sciences
Open Access status: gold
Estimated APC paid: $2,896
Funder: China Three Gorges Corporation
OpenAlex ID: W4415685075