赣江上游章水流域水沙变化的驱动力分析

为揭示赣江上游流域输沙量急剧减小过程中各影响因子的相对贡献率，以上游的章水流域为代表区域，采用流域控制站坝上水文站1956~2015年流域面雨量、径流和输沙数据，并结合趋势检验、Pettitt突变检验等方法，计算并分析了该流域多年降雨量、径流量和年输沙量的变化趋势和突变。采用累积量斜率变化率比较法分析了自然因素和人类活动在章水流域水沙关系变化中的相对贡献率。结果表明：流域降雨和径流60 a间无显著变化趋势和突变点，年输沙减少趋势显著，在1994年发生有超过显著性水平0.001的突变。相对于1956~1994年，在1995~2015年，人类活动对章水流域水沙关系的贡献率为99.4%；研究表明水利工程建设和水土保持等人类活动对赣江上游章水流域输沙量变化影响及其显著。研究对于准确评价水利工程和水土保持效益具有重要的指导意义。 关键词： 水沙关系；赣江上游流域；人类活动贡献率；双累积曲线

Contribution Rate Analysis of Driving Factors on the Rainfall-Sediment Relationship of Zhangriver Watershed in the Upper Region of Ganjiang Watershed

The sediment load dramatically decreased at Zhangshui River watershed,the upper Ganjiang River of China.Quantitatively analyzing the contributions of anthropogenic and climatic factors on the reduction would be helpful of better understanding the dynamic of hydrological processes.Based on the long-term hydrological and meteorological series,this study was aimed to analyze the trends and change points of annual precipitation and sediment loads from 1956 to 2015 at Bashang gauging station of Zhangshui River watershed.It was realized by the help of the trend test,Pettitt test,and comparision of changes in the slope of cumulative annual measured data vs years between the two connected periods.Consequently,a significant decreasing trend was revealed in annual sediment loads,whereas insignificant decreasing trends were detected for annual precipitation and annual runoff,respectively.Meanwhile,there was a change point of annual sediment in 1994.By the benefit of the double accumulative curve (DMC) method between the accumulative annual rainfall to sediment,the relative change point was recognized to be 1995.According to this relative change point,the whole period was divided into two connected parts of 1956-1994 and 1995-2015.The contribution rate of remarkable decline of sediment load in the upper region of Ganjiang River watershed in 1995-2015 was also obtained when the rainfall was taken for the indicator of natural factor.As a result,the contribution rate of the human intervention to sediment load was 99.4％ in 1995-2015,when the period of 1956-1994 was taken as a fundamental baseline.Integrating all these results,this paper could prove clearly that human intervention has a significant impress on rainfall-sediment relationship of Zhangshui River watershed.Also it has an useful meaning as a method to evaluate the benefit of soil and water conservation measures.The study provides scientific foundation for understanding the causes of water resources decrease and significant information for water resources management under the influence of climate change and human activities.