Channel Changes of the Makou-Tianjiazhen Reach dur ing the Past 40 Years in the Middle Yangtze River
长江中游马口—田家镇河段40 年来河道演变

Quantitative analysis was performed on filling and scouring process for the river reach between Makou and Tianjiazhen,the middle Yangtze River with the help of GIS and DEM technology.The research results indicate that the river reach between Makou and Tianjiazhen was dominated by the scouring process,and the magnitude of scouring is increasing over time.The intensity of scouring process is more in the deep and narrower river reach than shallower and wider ones.The river reach in the Makou and Tianjiazhen river knot is in frequent scouring and filling process,however the river reach upper to the Makou and lower to the Tianjiazhen river knot is in moderate scouring and filling process.The river reach just upstream or downstream to the river knot(e.g.Makou and Tianjiazhen river knot in this research) is dominated by filling process and the river reach in the river knot is dominated by scouring process.Research results indicate no changes happen in the boundary of the river but the scouring and the filling magnitude in specific river channel is strong.The filling and scouring process of the study river reach is greatly impacted by the sediments and water from the upstream of the study river reach.The construction of the Three Gorges Dam just upstream to Yichang will cause further decrease of the release of sediment load to the middle and the lower Yangtze River basin,which will further intensify the scouring process of the river channel in the study river reach.