Taohe River Main Current Runoff Change Characteristic Analysis

This according to the Tao River basin, the middle and lower reaches of the Chin groove, Minxian lijiacun, Red flag control hydrological stations measured four months, the annual flow of information, unified data series for the 1956-2006 period total of 51 years, on the Chin groove station and Minxian station runoff data series for interpolation, and the red point on the lijiacun station runoff data series for the natural runoff reduction. Utilized the different method to the Tao river runoff year, the year border change rule and the tendency has carried on the analysis.In the 50s until now, the Tao River basin runoff is increasingly uneven distribution of low, gradually from upstream to downstream change in uniform to uniform. The use of annual distribution uniformity coefficient, the year distribution of total adjustment coefficient, concentration and focus on the changes on the runoff rate and other indicators of change, the index change in the Tao River basin runoff for many years showed decreases in the trend, in the basins, middle and lower reaches show a growing trend. Tao River runoff throughout the year mainly in the flood season 7,8,9,10 months, rainfall is the main supply source of runoff Tao.Tao large annual variation of runoff, the overall trend showed decreases, the abundant even waterless year appears alternately.50,70,80's runoff flow period for the Tao River, Tao wet period for the 60's,90's to the early 21st century as the Tao continuous dry season; the average year on behalf of stations have appeared most often, dry conscription age of the high flow for at least. Coefficient of variation in the Chin groove stations upstream and downstream red points are equal, a larger middle coefficient of variation, that Tao River upstream and downstream inter-annual changes in runoff stability; middle reaches of some tributaries of import, inter-annual changes in runoff increased. Extreme than the annual runoff and annual change rate decreases gradually from upstream to downstream; Worse than the positive alues of model coefficients middle Minxian station and lijiacun station larger than the chin groove stations upstream and downstream Red point, that Tao River Runoff changed dramatically, in drought periods the process significantly. Tao rainfall runoff process and present the corresponding relation, changes in runoff varies with rainfall, runoff lag.MK rank through the traditional test and the latest Tao EMD method and the cyclical flow of mutation, the results show that:overall annual runoff of the Tao River basin has no significant decreasing trend, a significant jump; cycles show multiple time scales characteristic alternation of wet. Runoff reduction occurred mainly in the years 1969-1972 and 1986-2002; 1967-1968 and 2003-2006, a significant increase in runoff, dry the wet year of extra years. Tao River runoff in 2003 by the decreasing trend to the increasing trend of mutation; 1988,1989,1991, 1991, respectively, Chin groove station, Minxian station, lijiacun station, the Red point to reduce runoff from the cyclical trend of mutations year, from upstream to downstream mutations in the year to show the phenomenon of the gradual delay.Tao River basin, the middle and lower runoff consistent trend, cyclical fluctuations in the law. Runoff series there is 2-4a,4-12a,10-28a-scale fluctuations in three cycles, of which 2-4a and 10-28a time scale stronger. Forecast in 2006, after 2～7a there is a relative partial Tao River runoff period after the annual flow of abundance to be dry, a steady downward trend.