The 24th IAHR-APD Congress (24th IAHR-APD Congress)

508 / 2024-06-05 21:49:37

Evolution Mechanism of the River Channel and Sandbars at the Jingjiang Reach of the Yangtze River under the New Conditions of Water and Sediment

Three Gorges Reservoir,Jingjiang River,Sandbar,River channel,Evolution mechanism

Subtheme 7: Sediment Regulation and Management > Topic 1: Sediments Transport Dynamics

The impoundment of the Three Gorges Reservoir (TGR) has changed the characteristics of water and sediment transport in the downstream channel after the impoundment of TGR. Based on the latest measured hydrological data and prototype channel observation data, we analyzed the evolution characteristics and mechanism of the river channel and sandbars at the Jingjiang River after the impoundment of TGR. Results indicate the following: ①The suspended load concentration was largely decreased and the riverbed was eroded observably at the Jingjiang River after the impoundment of TGR. ②The low channel was eroded deeply and the water lever in the dry season drastically dropped after the impoundment of TGR. ③Many sandbars had shrunk and the most branches were deposited at the Jingjiang River in the past twenty years.④The changing of the water and sediment transport was the main influencing factor on evolution of the river channel and sandbars after the impoundment of TGR. ⑤The human activities such as the river sand excavation and the construction of the channel improvement project had greatly influenced on evolution of the river channel and sandbars at the Jingjiang River in the past twenty years.