Analysis on water-sediment transportation variation of Jingjiang River-Dongting Lake

The change of water-sediment transportation affects the flood control situation of the middle reaches of the Yangtze River.Based on the field data,the water-sediment transportation laws and effects are studied in this paper.Analysis results show that the variation caused the discharge increase of the Jingjiang River and the siltation in the Chenglingji-Luoshan reach.The water level of Chenglingji rises gradually,and it seriously imperils the flood control situation of the Jingjiang River and Dongting Lake.Using the river network's water-sediment mathematical model,the water-sediment transportation variation and its effects of the downstream river after the Three gorges reservoir completion are predicted.The results show that the highest water level of the Jingjiang River and Dongting Lake will lower,and that the flood control situation will be relieved due to the scour in the trunk stream water course.