DOWNSTREAM GRAIN-SIZE VARIATION TO INTERPRET RIVER-CHANNEL PROCESS-FORM IN THE MIDDLE-LOWER YANGTZE RIVER, CHINA
In 2000 and 2003, five-hundred and twenty (520) riverbed sediment samples were taken from the middle-lower Yangtze trunk channel to examine the river hydromorphological nature. Analytical result shows that the riverbeds mostly consist of mostly medium to coarse sands, but silty fine sand near the river coast. The result further indicates 12 zones (I-XII), identified as alternated coarse-fine-grained riverbed, except zone Ⅰ-Ⅲ. Grain-size associated hydrological parameters indicates higher values in the Jingjiang Reaches (Yichang to Chenglingji) (unit stream power: 5-18 N/ms, boundary shear stress: 14 N/m2 and mean flow velocity: 2-3.2 m/s), while the values obtained from Chenglingji downstream are considerable lower (＜5 N/ms, 1-4 N/m2 and ＜0.7-1.5 m/s). These, when comparing with on-site measured ADP flow column velocity, revealed the erosive riverbed sediment transport in the Jingjiang Reaches, and the accumulative riverbed transport downstream, especially from Wuhan to the river coast. Hydrological parameters together with grain size distribution saw a coarsening riverbed in the Jingjiang river course, largely due to damming since the last half-century. This corroborates the weakening sediment zonation in the Jingjiang Reaches, which we believe will further extend downstream to the river coast in the coming decades.
Grain size erosive and accumulative riverbeds sediment transport Damming effect Yangtze River
Zhanjiao Wang Zhongyuan Chen
G5-3, Tokyo Institute of Technology, 4259 Nagatsnta-cho, Midori-ku, Yokohama,226-8503, Japan East China Normal University, Shanghai 200062, China
国际会议
第16届亚太地区国际水利学大会暨第3届水工水力学国际研讨会(16th IAHR-APD Congress and 3rd Symoposium of IAHR-ISHS)
南京
英文
939-944
2008-10-20（万方平台首次上网日期，不代表论文的发表时间）