长江支流嘉陵江水沙变化趋势及其驱动因素分析

近20年来，嘉陵江流域输沙量明显减少，其变化将对长江三峡库区水沙运动以及泥沙冲淤变化等产生重要影响。根据嘉陵江控制水文站实测水沙资料，采用定量分析的方法，分析了嘉陵江流域年降水量、河道径流量和输沙量的变化趋势及其发生显著变化的临界年份。结果表明:嘉陵江流域的径流量和输沙量都有显著的减少趋势；年降水量没有表现出明显的变化趋势。年径流量及输沙量发生显著趋势性减小的临界年份分别为1993年和1984年。同时，利用历时曲线和双累积曲线两种方法，量化了嘉陵江流域径流量与输沙量的减少量，定量分析了降水和人类活动对嘉陵江径流及输沙量的影响，进一步探讨了嘉陵江流域水沙变化的驱动因素。

Trend and Driving Force Analyses of Streamflow and Sediment Discharge in Jialing River

The sediment discharge in Jialing River basin has decreased significantly over the past 20 years.This change will have a major impact on the Yangtze River Three Gorges reservoir area of water and sediment movement and changes in sediment yield and deposition.The objectives of this study are to quantify the decreasing trends of precipitation,streamflow and sediment discharge during 1956-2008 and to statistically identify change points or transition years in the changing trends.Results showed that strong decreasing trends in annual streamflow (P=0.05) and sediment discharge (P=0.01) have existed since the late 1950s at Beibei hydrologic station of the Jialing River.Change point analysis reveal that more rapid declines for streamflow began in 1993,and sediment discharge began in 1984 at the stations (P=0.05).Two kinds of methods,namely duration curve and double mass curves,were applied to analyze change of streamflow and sediment discharge in Jialing River basin.The reasons for the trends and change-points in streanflow and sediment discharge were analyzed finally.