50年来灞河流域水沙变化特征分析

根据灞河流域水沙特点,选取反映灞河流域水沙变化趋势的马渡王水文站,利用灞河流域50年的实测年径流量和年输沙量资料,采用Mann-Kendall非参数统计检验法、小波分析法、双累积曲线法,结合流域降雨量分析了灞河流域水沙年际变化特点及突变的年份。结果表明:灞河流域水沙年内分配极不均匀,水沙总体下降趋势明显;水沙序列具有多时间尺度特征,但变化尺度并不一致;径流量和输沙量分别在1989年和1981年发生了突变,但突变时间具有差异性,且输沙量的敏感性更强;进一步分析表明,降雨量的波动是径流量年际变化的主要影响因素,而输沙量的减少则主要受到径流量和人类活动的综合影响。

Characteristics of flow and sediment of Bahe basin in recent 50 years

Based on observed data at hydrologic stations in recent 50 years,the variation trends of runoff and sediment discharge in the upper reaches of the Bahe River were analyzed.Non-parameter statistical methods of Mann-Kendal test,wavelet analysis and double mass analysis,combined with basin rainfall analysis,the interannual variability of flow and sand characteristics and mutation of the year in Bahe river basin.The results show that the distribution of flow and sediment in the Bahe River Basin is extremely uneven and the annual water and sediment transports take a significantly downward trend.Both the water and sediment sequences had particular multi-scale and multi-resolution attributes,but the scale of each was not completely consistent.The runoff and sediment transport rates were changed in 1989 and 1981,respectively,but the mutation time was different and the sediment load was more sensitive.Further analysis show that the fluctuation of rainfall is the main influencing factor of interannual variation of runoff,while the decrease of sediment load was mainly affected by the combined effects of runoff and human activities.