关键词: 径流变化, 趋势分析, 党河

Abstract: Based on the historical records measured from the Shazaoyuan hydrological station on Danghe river, the annual variation characteristics of the runoff into the Danghe reservoir have been studied by using the methods of Frequency Factor Ranking Classification and Spectrum Analysis. In general, the processes of multi-year runoff variation included 3 low water periods, 3 normal water periods and 3 high water periods. If at a decade scale, 1950s and 1960s were low water stages, 1970s and 1990s were normal water stages and 1980s were high water stages. Generally speaking, the appearing probability of low water and high water was similarly more, but that of normal water relatively less. Further, there were the 2~3 years, 6 years, 10~11 years and 22 years variation periods in the runoff processes into the reservoir, especially the 6 years, 10~11 years and 3 years were more evident. Based on the above analysis, the GM(1, 1) model of residual error series with modified period was built up with the Gray System Theory, by which the variation trend of the runoff into the reservoir in future is predicted. The research results show that the runoff will increase smoothly and the annual mean will be slightly greater than the multi-year average in the early some years of 21 Century due to the precipitation will be increased in the west of Qilian mountain that resulted from the change of weather system.

Key words: runoff variation, trend analysis, Danghe