甘肃瓜州榆林窟历史洪水及其重现期研究

Historical Floods and Their Recurrence Intervals in Yulin Cave,Hexi Corridor

野外实地考察了河西走廊榆林窟1911年历史洪水,对洪水断面进行测量,采用积分的方法恢复其过水断面,分别用比降面积法和水位流量法重建其洪峰流量,并用历史洪水排位法推算其重现期。比降面积法重建洪峰流量结果为879 m3·s-1,水位流量法重建结果为738 m3·s-1,两种方法推求结果相差不大,取其均值809 m3·s-1作为最终流量推求结果。重现期的推算结果表明,榆林窟1911年的历时洪水重现期为105 a。研究结果延长了榆林河的洪水记录尺度,为榆林窟在全球变暖背景下的防洪减灾提供了依据。

Field observations and measurements of historical floods at Yulin Cave in the year of 1911 were conducted. The flood area was measured using a Leica TS06 Total Station,and the integration method was used to calculate flood area. The stage-discharge and slope-area methods were applied to calculate the peak discharge,and the rank method was used to calculate the recurrence intervals. Peak discharge values calculated by the stage-discharge and slope-area methods were 879 m3·s-1 and 738 m3·s-1 respectively. These two results were similar,and their difference was only 9. 6%. Therefore the mean value of 809 m3·s-1 was taken as the estimated peak discharge.Furthermore,the calculations using the rank method suggested that a recurrence interval for the flood magnitude in the year of 1911 was 105 years. This work extended the flood record period for the Yulin River,and could provide a reliable basis for constructing flood control facilities at Yulin Cave in the context of global warming.