Variations of the Hydrological Characteristics and Driving Factors in the Yihe River Basin
2011, 30 (11):
Taking the Yihe River basin as a study region, this paper analyzes the variations of hydrological characteristics such as precipitation, runoff and peak discharge, during the period 1951-2002. Time series analysis methods, such as the Kendall method and orderly cluster analysis are used to test the change trend and the mutation of precipitation-runoff. The influences of climate change and human activities on runoff were examined quantitatively based on the comparison between the observed runoff and regression simulation data of the natural runoff at Linyi hydrological station. Some conclusions are drawn as follows. (1) During recent 50 years, the Kendall test value of the annual precipitation is -1.028 at Linyi hydrological station, showing that the precipitation decreased slightly. However, the value of annual runoff is -3.689, decreased evidently, and monthly runoff shows the same trend. That is the responses of runoff to precipitation tend to be weak. But the change trend of rainstorm runoff shows that single storm-runoff keeps strong consistency with rainfall. (2) Based on the runoff mutation, the annual precipitation-runoff process can be divided into three periods, 1951-1964, 1965-1975, and 1976-2002. In the 10-year scale, the observed runoff shows a relatively consistent trend with rainfall. To some extent, precipitation controls the evolution of runoff. (3) Since the mid-1960s, the mean annual runoff at Linyi hydrological station decreased by 148.8 mm, accounting for 51.6% of the mean annual natural runoff. The contribution rate of climate change and human activities to runoff reduction is 39.3% and 60.7%, respectively. The human activities, such as hydraulic engineering construction, land use and land cover change and water resources development, have a profound impact on runoff. The river basin sustainable development requires reasonable constraints to human activities to comply with the nature law of hydrological cycle.
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