Analysis of river-course evolution on the Changjiang-Lujiahe river after water impoundment of the Three Gorges

Since the impoundment of Three Gorges reservoir,water and sediment to the downstream reach has changed,resulting in the process of river transformation on the Changjiang-Lujiahe river and erosion of the bed.Based on the latest prototype observation data of the reach after construction of the Three Gorges project,we analyzed the silting and erosion of river bed of this micro-bending and bifurcated reach.The result shows that the river bed has eroded in general and the right branch of shingle flat scours more than the left.the tail part of shingle flat scours in large area,and it has an unpredictable effect on the diversion ratio and navigation on this reach.Some part of this reach eroded only a little,they have a strong anti-scour ability,which is one of the main reasons for the less drop of dry water level after the mpoundment of the Thress Gorges reservoir.