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黄河下游泥沙沉积汇在黄河流域系统的泥沙收支平衡(Sediment budget)中起着重要的作用。通过河床主槽中泥沙的淤积和冲刷,运动泥沙的组成发生变化;通过滩地上泥沙淤积和河岸坍塌,河漫滩上前期淤积的泥沙与洪水所挟带的泥沙发生交换,使悬移质泥沙的组成发生变化。泥沙冲淤量对不同粒径组入海泥沙百分比的影响是不同的。小于0.01mm细泥沙的百分比与下游河道淤积量呈正相关,0.0250.05mm和大于0.05mm的较粗泥沙的百分比与下游河道淤积量呈负相关。入海泥沙平均粒径与深泓年摆幅之间也存在着负相关关系。自20世纪60年代,中期以来,特别是自80年代中期以来,由于黄河下游径流量显著减小,黄河下游河道发生萎缩,河宽减小,因而主流线的摆动幅度也显著减小。这使得原来十分强烈的河岸侵蚀和滩槽泥沙交换强度大为减弱,主槽洪水得到的来自河岸侵蚀的细粒泥沙越来越少,因而使入海泥沙粒径变粗。
Abstract：The lower Yellow River can be regarded as one of the sediment sinks in the river drainage basin,which plays an important role in the sediment budget of the river system.Through sediment deposition and scour in main channel,composition of sediment in motion changes;through sediment deposition on floodplain and bank erosion,exchange occurs between the sediment on floodplain and the sediment in motion.Thus,composition of suspended sediment changes along the river.It is found that sediment deposition has different effect on various fractions in sediment flux to the sea.The percentage of fractions finer than 0.01mm in the sediment flux to the sea is positively correlated with sedimentation amount in the lower Yellow River,but negative correlations exist between sedimentation amount and the percentages of fractions in the range from 0.025mm to 0.05 mm and coarser than 0.05mm in the sediment flux to the sea.The average diameter of sediment flux to the sea is found to be negatively correlated with the annual shift of the thalweg of the lower Yellow River.Since the mid-1960s,especially since the 1980s,water discharges of the lower Yellow River decreased significantly and the channel shrinkage occurred,the channel width decreased and so did the annual shift of the river's thalweg.As a result,bank erosion weakened,and the sediment exchange between main channel and floodplain became less intensive than that in the previous period.Since the floods in the main channel could get less fine sediment from the floodplain,the grain size of suspended sediment flux to the sea tended to become coarser.
[1]Schumm,S.A.,The Fluvial System.New York:John Wiley,1977,138.
[2]Renwick,W.H.;Ashley,G M.Sources,storages,and sinks of fine-grained sediments in a fluvial-estuarine system.GeologicalSociety of America Bulletin.1984.95(11),pp 1343-1348.
[3]Asselman,N.E.M.,1999.Suspended sediment dynamics in a large drainage basin:the River Pdline.Hydrological Processes 13(10),1437-1450.
[4]Brasington,J.,Richards,K.,2000.Turbidity and suspended sediment dynamics in small catchments in the Nepal Middle Hills.Hydrological Processes 14(14),2559-2574.
[5]Milliman,J.D.,Meade,R.H.,1983.World-wide delivery of river sediment to the oceans.Journal of Geology 91(1),1-21.
[6]Milliman,J.D.,Syvitski,J.P.M.,1992.Geomorphic/tectonic control of sediment discharge to the ocean.Journal of Geology 100,525-544.
[7]Phillips;J.M.,Walling,D.E.,1999.The particle size characteristics of fine-grained channel deposits in the River Exe Basin,Devon,UK.Hydrological Processes 13(1),1-19.
[8]Walling,D.E.,Kane,P.,1984.Suspended sediment properties and their geomorphological significance.In:Burt,T.P.,Walling,D.E.(EdS.),Catchment Experiments in Fluvial Geomorphology.GeoBooks,Norwich,pp.311-344.
[9]Wailing,D.E.,Moorehead,P.W.,1987.Spatial and temporal variation of the particle-size characteristics of fluvial sediment.Geografiska Annaler 69A(1),47-59.
[10]Walling,D.E.,Moorehead,P.W,1989.The particle size characteristics of fluvial sediment:an overview.Hydrobiologia 176/177,125-149.
[11]Walling,D.E.,Webb,B.W.,1992.Water quality:I.Physical characteristics.In:Calow,P.,Petts,G.(Eds.),The RiverHandbook.Blackwell,London,pp.48-72.
[12]Xu,J.,1997.The optimal grain-size composition of suspended sediment of hyperconcentrated flows in the middle Yellow River.International Journal of Sediment Research 12(3),170-176.
[13]Xu,J.,1998.A study of physico-geographical factors for formation of hyperconcentrated flows in the Loess Plateau of China.Geomorphology 24,245-255.
[14]Xu,J.,2000.Grain-size Characteristics of suspended load sediment of the Yellow River,China.Catena 43(2),176-186.
[15]Xu,J.,2002.Implication of relationships among suspended sediment size,water discharge and suspended sedimentconcentration:the Yellow River basin,China.Catena 49(2002)289-307.
[16]钱宁,周文浩.黄河下游河床演变[M].北京:科学出版社,1965.
[17]钱宁,万光惠.泥沙运动力学[M].北京:科学出版社,1983.
[18]许炯心,孙季.黄河下游游荡河道萎缩过程中的河床演变趋势[J].泥沙研究,2003,(1):10-17.
基本信息:
DOI：10.16239/j.cnki.0468-155x.2005.06.003
中图分类号:TV148
引用信息:
[1]许炯心.黄河下游泥沙沉积汇对入海悬移质泥沙粒度的影响[J].泥沙研究,2005(06).DOI:10.16239/j.cnki.0468-155x.2005.06.003.
基金信息:
国家自然科学基金资助项目(40471017);; 中国科学院知识创新工程重要方向项目资助项目(KZCX2-20705)
2005-12-20
2005-12-20