流量过程对平滩流量的影响

在分析年平滩流量与来水来沙关系的研究中多关注当年或多年水量、沙量、水沙系数等总量特征参数, 部分研究中增加考虑了洪峰峰值等特征参数, 而针对流量过程对年平滩流量影响的研究较少。通过花园口断面 1954- 2000 年实测流量过程及大量实测断面资料, 采用流量历时曲线法来描述流量过程, 采用改进的 WOL 方法估算实时平滩水位, 进而估算年/实时平滩流量, 分析流量历时曲线特征参数与年/实时平滩特征之间的关系。分析认为, 在流量峰型扁平时, 断面的年/实时平滩水深基本不变, 断面形态变化不大; 当流量峰型尖瘦时, 断面的年/实 时平滩水深变化较大, 断面形态变化较大。分析认为, 影响年平滩流量的水沙特征参数除水量、沙量、水沙系数等表征总量特性的参数外, 还应该适当考虑流量过程的影响, 即流量过程峰型相对尖瘦时年/实时平滩流量均变化较大。 The analysis of the relationship between annual bankfull discharge and inflow mainly focuses on the quantity of runoff and sediment loadat the annual scale (such as water amount, sediment load, and water-sediment coefficient) . Some researchers may also consider some specific characteristics such as peak discharge. However, few studies focus on the discharge hydrograph. We collected measured data of discharge and cross-sections at Huayuankou Hydrology Station during 1954-2000, and adopted flow duration curve (FDC) to describe the discharge hydrograph. Then, we used improved MOL method to estimate the bankfull discharge at different temporal scales, both annual and real-time. The relationship between the coefficients of FDCs and bankfull depth ( annual and real-time) was investigated. The analysis showed that when the discharge changed dramatically, the bankfull discharge was more likely to change, and so was the morphology of cross-sections. In conclusion, in addition to the quantity of runoff and sediment load, discharge hydrograph may also influence the bankfull discharge ( annual and real-time) . 国家自然科学基金( 51109198; 51579230)