沂河流域水沙变化趋势及成因分析

为了揭示变化环境下沂河流域径流量和输沙量减少的原因，选取反映该流域水沙变化趋势的代表水文站——临沂站，利用50余年来的实测年径流量及年输沙量资料，采用滑动平均法、Mann-Kendall非参数秩次相关检验法，对该流域水沙变化趋势进行了研究。结果表明:在一定显著性水平下，沂河流域径流量与输沙量在多年变化中均呈明显下降趋势。最后，针对影响水沙变化的降水与人类活动因素，应用不同时段的雨—水—沙关系，定量计算了不同时段的水沙衰减量以及由于雨水衰减影响和水土保持影响的减沙量所占比重。针对临沂的实际情况，应继续加强水土保持工作，实施流域综合治理。

Analysis of Variation Trends and Cause of Runoff and Sediment in Yihe River Basin

In order to reveal the cause for reduction of runoff and sediment in the changing environment, bases on the observed data in the past 50 years at Linyi hydrologic sation that reflects the hydrological variation trends of runoff and sediment in the Yihe River Basin, through several non-parameter statistical methods such as the moving average check and the Mann-Kendall test, we analyzed the trends of runoff and sediment in the river basin. The results showed that the runoff evolvement and sediment transport at the Linyi Hydrologic station presented the significant decrease trend. In view of the major factors correlated with the runoff and sediment transport changes such as the rainfall, soil conservation, the sediment descending proportions caused by the reduction of rainfall and soil conservation were valuated based on the relationships between rainfall, water and sediment. According to the actual situation of Linyi City, the work of soil conservation and implement comprehensive management in the river basin should be continued to strengthen.