110 / 2024-02-06 10:50:08

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

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

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 sandbars and river channel 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. ②Many sandbars had shrunk and the most branches were deposited at the Jingjiang River in the past twenty years. ③The low channel was eroded deeply and the water lever in the dry season drastically dropped after the impoundment of TGR. ④The changing of the water and sediment transport was the main influencing factor on evolution of the sandbars and river channel after the impoundment of TGR.⑤The human activities such as the river sand excavation and the construaction of the channel improvement project had greatly influenced on evolution of the sanbars and river channel at the Jingjiang River in the past twenty years.