147 / 2024-02-20 21:55:10

Evaluations of river channel evolution and impacts in the middle Changjiang River over the past two decades

Large reservoirs; Hydro-sediment regime; River channel evolution; multifaceted influences; Middle Changjiang River

Under the influence of human activities, particularly the construction of large reservoirs, the comprehensive impact on rivers has become a globally focal point of research. It holds crucial implications for reservoir planning, river conservation, and management. The construction and operation of the Three Gorges Reservoir (TGR), along with other mega dams constructed upstream, have resulted in significant alterations to the hydro-sediment regime, exerting multifaceted influences on river. This study focuses on the channel evolution and impacts in the middle reach of the Changjiang River over the past two decades, based on the analysis of measured data since the operation of TGR in 2003. This study elucidated the spatiotemporal variation in runoff and sediment flux. In the past 20 years, the overall runoff in the middle reach of the Changjiang River has remained stable, while the distribution has been flattened. Sediment flux has significantly decreased by over 85%, and the distribution within the year has become more concentrated. From 2003 to 2021, the middle reach of the Changjiang River experienced a scouring of approximately 2.6 billion m³, with an average scouring depth of about 2.8 m. Subsequently, an assessment of the comprehensive impacts of hydro-sediment regime changes and river channel evolution on flood control, navigation, and river infrastructure is conducted. The research findings contribute to supporting the conservation and management of the Changjaing River, and provide valuable insights for the management of similar river basins worldwide.