黄河干流头道拐水文站水沙运动特征及影响因素

Characteristics and Impacting Factors of Flow-Sediment Movement at Toudaoguai Hydrological Station of the Yellow River

为明确黄河干流头道拐水文站水沙运动过程、变化趋势及运动状态特征,以2006—2018年黄河干流头道拐水文站水沙数据为基础,基于累积距平法、R/S极差分析法、河道来沙系数与不协调度等研究方法,对头道拐水文站水沙运动过程进行系统分析。结果表明:头道拐水文站年际间径流与输沙量和年内月均径流与输沙量变化趋势均呈现良好的一致性,但两者的季节性差异特征显著,且输沙量的显著性较径流更突出;冬季径流与输沙量变化趋势同步性相比其他季节较差,季节性的极差Hurst指数揭示了冬季输沙量变化趋势的反持续性和水沙不协调性易引起河道的冲淤演变;以来沙系数为水沙状态的划分依据,春季、夏季和秋季水沙特征多呈现水少沙多的状态,而冬季水沙状态则为水多沙少,水沙协调状态会出现在春季个别年份;季节性水沙不协调度总体呈夏季>秋季>春季>冬季的变化特征,特殊的来水来沙过程、水文气候特征及人类活动变化是造成水沙不协调的主要影响因素。

To clarify the characteristics of flow-sediment movement process,changing tendency and movement state of Toudaoguai hydrologic station of the Yellow River,based on the flow and sediment data of Toudaoguai hydrological station in the Yellow River from 2006 to 2018,the flow-sediment movement process was systematically analyzed by using the cumulative anomaly,R/S range analysis,sediment coefficient and incoordination degree methods.The results showed that the inter-annual and monthly average variation of flow-sediment discharge in Toudaoguai station were well consistent,but the seasonal differences between them were significant,and the significance of sediment discharge was more prominent than runoff.Compared with other seasons,the synchronicity of variation trend of flow and sediment discharge in winter was worse.The Hurst index of seasonal revealed that the reverse persistence of the variation trend of sediment discharge,and the incongruity of flow and sediment in winter,could easily lead to erosion and deposition of the river channels.Based on sediment coefficient,which was the basis for the division of water and sediment states,the flow and sediment states were divided into three types,less water and more sediment was the characteristics of flow and sediment state in spring,summer and autumn,while in winter the state was more water and less sediment,and the flow-sediment coordination state appeared in spring of very few years.The incoordination degree of seasonal flow-sediment followed the order of summer>autumn>spring>winter.The special water and sediment inflow process,hydrological and climatic characteristics and human activities were the main factors influenced the imbalance of flow and sediment.