Abstract:

For hydrological regime,Jingjiang segment is the most dangerous part of the Yangtze River.Due to elevation of Jingjiang beach,warping of Dongting Lake,heightening of water level at same discharge and thus the silting of Jingjiang on one hand,and structurally controlled subsidence of basin on the other hand,the potential difference between flood level and basin ground keeps increasing continuously,and high embankments and high flood stage(more than 13 m above the embank ground)along Jingjiang Segment is formed.Although establishment of the Three Gorges Reservoir has brought about great regulation and storage capacity against the flood in the Upper Yangtze River,it has not changed the geological process.This leads to the formation of high flood stage in Jingjiang Segment.Heightening of the levee and the flood stage are accompanied with disastercausing geological processes such as embankment piping,shore collapse,earthquake etc..The Jingbei Plain is severely threatened because Jingjiang river segment has a natural streaming tendency to burst from the Yangtze River,and the Yanka section at the Shashibay is more dangerous.To avoid great geological and environmental disasters and to harmonize the relationship of human,land and water,strategies for giving way to river water and sand as well as for utilization of flood resources are urgently needed.