不同因素对城陵矶水位变化贡献率的分析

Analysis of Variation Characteristics of Water Level at Chenglingji and Its Contribution of Influencing Factors

为分析不同因素对城陵矶水位变化的贡献率,基于1955~2014年实测水文资料,利用Mann-kendall检验法、回归分析等方法分析城陵矶水位变化特征及其成因。结果表明,下荆江裁弯和葛洲坝的运行对城陵矶水位流量关系造成较大影响,同流量下城陵矶水位增幅明显,而三峡水库对城陵矶水位流量关系影响不大;1972~2002年水位流量出现"此消彼长"的现象,主要是因为干流顶托作用加强和断面逐年淤高对水位的抬高值大于因流量减小对水位的减小值所致;城陵矶水位于1967年发生突变,这与1967年中州子裁弯有一定联系,而四水入湖流量的减少是1977年流量发生突变的主要原因;通过构建模型,计算得出下荆江裁弯、葛洲坝和三峡水库的运行在各自所在时期对城陵矶水位变化的贡献率分别为50.3%、50.5%、56.8%。

In order to analyze the variation characteristics of water level at Chenglingji and its contribution of influencing factors,Mann-kendall test,regression analysis and other techniques,were used to analyze the variation characteristics of water level and its causes,based on the observed hydrological data from 1955 to 2014.The results show that the cut bends of lower Jingjiang and the operation of Gezhouba have great impact on the relationship between water level and flow at Chenglingji,which lifted the water level of Chenglingji under the same flow conditions.However,the operation of Three Gorges Reservoir has little impact.The relationship between water level and flow during 1972-2002 occurred as the phenomenon of‘the flow has a general trend of decreasing while the water level has an obvious trend of increasing',which was mainly caused by the fact that the raising of water level owing to the reinforced backwater effect and the undergoing deposition year by year is greater than the fall of water level caused by the reduced flow.The water level of Chenglingji had a sudden change in 1967,which has a certain connection with the cut-bend of Zhongzhouzi.In addition,the reduction of the flow of Lishui,Yuanshui,Zishui and Xiangshui is the main reason for the sudden change in 1977.The contribution of four upstream branches and three water inlets to the changes of water level at Chenglingji were calculated by building the model,and cut bends of lower Jingjiang and the operation of Gezhouba and Three Gorges Reservoir contribute 50.3%,50.5% and 56.8%,respectively.