中文摘要：

利用河道断面测量数据计算了1960～1990年渭河下游河槽和滩地冲淤量及其分布的时空变化，分析了变化发生的原因。结果表明：1960～1990年问共淤积泥沙8．88x10^8m^3且泥沙主要分布在渭淤11断面（WYll）以下河段。滩地淤积量是河槽的1．83倍，滩地冲淤过程以1968年和1982年为转折点分为3个阶段，依次经历了快速淤积、缓慢淤积和侵蚀3个过程。其中淤积以滩面垂向加积为主，侵蚀主要表现为河岸侵蚀后退或坍塌。河槽以1969年为转折点分为快速淤积和轻微淤积（冲刷淤积交替）两个阶段。年内滩地和河槽在汛期整体上淤积，非汛期滩地侵蚀（主要以河道侧向侵蚀形式），而河槽表现为微淤，滩地在汛期堆积和非汛期侵蚀的倾向较河槽明显。三门峡水库在蓄水拦沙（1960年9月-1962年3月）和滞洪排沙（1962年3月～1973年10月）阶段，泥沙淤积上延到渭淤17（WY17）和渭淤27断面（WY27）间河段；实行蓄清排浑（1973年11月～1990年）后溯源淤积大为减弱，淤积未再上延，河道冲淤趋向于平衡。潼关高程是影响河槽和滩地泥沙淤积和释放的主要原因之一。此外，滩地的冲淤量与当年汛期来沙量相关性最高，而河槽冲淤量与当年汛期径流量相关性最高。

英文摘要：

Cross section measurements were used to calculate the amount and patterns of sediment accumula tion and erosion on floodplains and in channel at various spatial and temporal scales in the lower reaches of the Weihe River in 1960-1990, and the causes for the changes in the amount and patterns of sediment accumula- tion were investigated. Result showed that the total sediment storage amounted to 8.88 × 10^8 m^3 in 1960-1990. The amount of sedimentation on floodplain was 1.83 times larger than that in channel and sediment deposition mainly happened in the reaches down the cross-section WYll. By two break points in 1968 and 1982, sedi mentation process on floodplain was divided into there stages characterized by fast deposition, slow deposition and sediment release in sequence, in which deposition occurred mainly in the form of vertical accumulation and sediment release mainly resulted from the retreat of river banks. The sedimentation process is channel changed abruptly in 1969. The stage before the year 1969 was featured by fast deposition and with some alter mations between deposition and erosion that after the year 1969 was characterized by slight deposion. Sedi ment aggradation occurred in both floodplain and channel during flood periods, and sediment was released from the floodplain in the form of river bank erosion and weak aggradation took place in channel during the low flow periods. The sediment trapping and releasing was more significant in floodplain than in the channel during these two stages. The sediment deposition extended upstream to the reach between WY 17-WY27 when the operation mode of Sanmenxia Dam was storing all water and sediment during 1960-1963 and detaining the floods and sluicing sediment from March 1962 to October 1973, but no more serious further headward sedi ment deposition occurred when the operation mode was detaining clear water and releasing muddy water from November 1973 to 1990. Sediment deposition on floodplain and in channel was affected mainly by Tong- guan elevation, which i