黄河上游宁蒙河段平滩流量变化与水沙过程的响应关系

Variation of bank-full discharge and its response relationship with flow and sediment processes of Ningmeng reach in Upper Yellow River

平滩流量是表征河道排洪输沙能力的重要指标,开展宁蒙河段平滩流量变化机理的研究对于治理黄河意义重大,本文采用实测资料分析的方法,研究了黄河上游宁蒙河段平滩流量变化特征及其与汛期水沙过程的定量关系。研究结果表明:黄河上游宁蒙河段沿程六站平滩流量由1960年代中期的3600~5800 m^(3)/s减小到目前的1900~4000 m^(3)/s。2000年前宁蒙河段三湖河口平滩流量与汛期水沙过程关系点群与2000年后两者关系点群存在明显分区,说明2000年后宁蒙河段河床演变机理发生了变化,遵循不同规律。建立的宁蒙河段三湖河口平滩流量与汛期水沙过程的定量关系式表明,宁蒙河段平滩流量随着汛期平均水量的减小(增大)而减小(增大),随着汛期平均来沙系数的减小(增大)而增大(减小),随着汛期水流过程参数的增大(减小)而增大(减小)。

Using the methods of data analyses,Variation of bank-full discharge and its response relationship with flow and sediment processes of Ningmeng reach was researched in Upperr Yellow River.The result show that,the variation trend of bank-full discharge of Ningmeng reach is to decrease in Upper Yellow River.From^(3)600-5800 m^(3)/s in the mid-1960s to the current 1900-4000 m^(3)/s.Compared with before 2000 and after 2000,there are obvious subregions of the point group of relationship between bank-full discharge of Sanhuhekou and flow and sediment processes of flood season.The evolution mechanism of Ningmeng reach changed in Upperr Yellow River after 2000,and follows different rules.According to the established relationship between bank-full discharge of Sanhuhekou and flow and sediment processes of flood season,the bank-full discharge increases(decreases)with the increase(decrease)of water quantity of flood season,it increases(decreases)with the decrease(increase)of the coming sediment coefficient of flood season,it increases(decreases)with the increase(decrease)of the flow process parameter of flood season.