近50年来乌江水沙特征变化研究

Evolution Processes of Annual Runoff and Sediment Changes in Wujiang River in Past 50 Years

为了评价乌江流域近50余年来河流径流泥沙变化特征,运用Mann-Kendall非参数检验、均值差异T检验、双累积曲线法和小波分析等方法对武隆水文站长时间实测径流泥沙数据进行探究表明,年径流量无明显下降趋势,而年输沙量下降趋势显著;研究期间内年径流量未发生突变,年输沙量在1992年发生突变;年径流量和年输沙量存在以25~28 a为主周期的变化规律;武隆站年径流量和年输沙量可划分为1956年~1976年,1977年~1993年,1994年~2015年3个阶段,水沙关系在1974年~1993年变化最为明显;水库拦沙是导致年输沙量显著减少的重要原因。

In order to evaluate the evolution characteristics of river runoff and sediment in Wujiang River Basin in past 50 years,the methods of Mann-Kendall nonparametric test,average difference T test,double cumulative curve method and wavelet analysis are used to analyze the long-times series data of annual runoff and sediment at Wulong Hydrological Station.The results show that:(a)the amount of annual runoff shows a slight decreasing trend and the amount of annual sediment shows an obvious decreasing trend;(b)during the study period,there is no abrupt point for runoff,but the amount of sediment has a abrupt change in 1992;(c)there are periodicities of 25 to 28 years for annual runoff and sediment processes respectively;(d)the variation of annual runoff and sediment transport at Wulong Hydrological Station can be divided into three stages of 1956-1976,1977-1993 and 1994-2015,and the relationship between water and sediment changed most obviously from 1977 to 1993;and(e)the significant reduction of annual sediment transport is mainly contributed from water conservation engineering.