Analysis Of Components Of Streamflow Evolution Characteristics And Driving Factors In Xinshui River On Loess Plateau

Xinshui River is the representative river in the Loess Plateau Region,which is one of the most severe areas suffering from soil erosion.It is necessary for developing researches on the variation of baseflow and surface flow under climatic variation and human activities.We separated baseflow with eight baseflow seperation methods.With the comparison of the discharge curve,reliability and stability,we found out the most suitable baseflow separation method and calculated the baseflow and surface flow in Xinshui River Basin.After that,trend analysis method,mutation analysis method,periodic analysis method and the nonuniform coefficient method were used to ca culate the annual and interannual variation of baseflow and surface flow.The double curve method and linear fitting analysis method were used to calculate the relative contribution rate of the various meteorological and non-meteorological factors.The result indicated that DF one(0.925,three times)method was the most stable and reliable one among all selected methods.The average depth of the baseflow and surface flow was 11.29mm and 19.40mm,respectively.The distribution of baseflow and surface flow was not uniform in each month and season.On the multi-year average scale,the distribution of baseflow was relatively uniform,and the distribution of surface runoff was extremely uneven.The concentration period of annual baseflow and surface flow distribution was consistent with the actual distribution in a year,while the concentration period in different periods was consistent.Baseflow and surface flow in Xinshui River showed a significant downward trend from 1955 to 2015,with the mutation points appearing in the year 1985.Both baseflow and surface flow showed a periodic change with 27a.In the base period,precipitation was the main factor which affected the baseflow and surface flow.When it comes to the disturbed period,non-meteorological factors mainly affected the baseflow and surface flow in the disturbed period.In the 21st century,vegetation factors were more than that of meteorological factors on baseflow and surface flow.Other factors were the main factors that affected baseflow and surface flow variation.In the disturbed period,the relative contribution rate of meteorological,vegetation and other factors was 16.7%,3.3%and 80.0%and 19.2%,4.0%and 76.8%to the baseflow and surface flow.