Acta Geographica Sinica ›› 2000, Vol. 55 ›› Issue (3): 309-317.doi: 10.11821/xb200003007
LI Li juan, ZHENG Hong xing
In this paper, stochastic hydrologic methods are applied to analyze the characteristics and driving forces of annual runoff changes of Chaobaihe River, which is regarded as a typical river in North China. To find out the trend of annual runoff changes, the Kendall method was adopted. The results showed that the amount of annual runoff in the Chaobaihe River tends to decrease exponentially from the 1920s to the 1990s. Moreover, with the application of change point searching technology, it can be concluded that the runoff change history of the river can be divided into five periods, i.e., before 1960, 1960～1970, 1971～1980, 1981～1990 and after 1991. Besides that, the auto correlation function has shown that the runoff series is not an independent one. The auto correlation coefficients of its first, second and third orders are all quite significant. Furthermore, from the annual runoff records, it is found that since the phenomena of flow drying has become more and more serious in the region, the Chaobaihe River tends to be a seasonal river. In order to find out the driving forces of the annual runoff changes, we have analyzed the relationship between precipitation and runoff. Through correlation analysis, it is quite clear that the change in annual runoff was partly dependent on rainfall. However, the rainfall is not the only major driving force of the changes, for changes in annual runoff and rainfall are not entirely the same. Comparing the history of water resources utilization and development with change in annual runoff, we found that the annual runoff responded directly to human activities, especially after 1960. According to the investigation, it was obvious that the annual runoff change is mainly caused by human activitives rather than under the impact of the climate change, though the climate serves as the background of the change. Since the relationship between rainfall and runoff was quite well before 1960, a regressive function is built based on the series of rainfall and runoff from 1920 to 1960. And then, the function is used to extend the series of natural runoff by relying on the records of rainfall after 1960. Thus the estimated rates of water utilization and development of different periods were calculated. The results showed that the rate of water utilization and development has been increasing continuously and has been far beyond the limited rate of 40%. It brooks no delay to control water resources development and utilization in the Chaobaihe River.
LI Li juan, ZHENG Hong xing . Characteristics and Driving Forces of Annual Runoff Changes for Rivers in North China ——A case study in the Chaobaihe River[J].Acta Geographica Sinica, 2000, 55(3): 309-317.
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